High-temperature gas-cooled reactors inc pebble-bed modular reactors

The checkered history of high-temperature gas-cooled reactors

Academic M.V. Ramana has written a useful summary of the troubled history of high-temperature gas-cooled reactors (HTGR) including the pebble-bed reactor sub-type. In the past, both Germany and the United States spent large amounts of money to design and construct HTGRs, four of which fed electricity into the grid. Other countries have also invested in HTGR technology. Ramana’s analysis is of more than historical interest as several countries are either considering the construction of new HTGRs or pursuing research into the field.

Ramana writes:

“Proponents of HTGRs often claim that their designs have a long pedigree. … But if one examines that very same experience more closely – looking in particular at the HTGRs that were constructed in Western Europe and the United States to feed power into the electric grid – then one comes to other conclusions. This history suggests that while HTGRs may look attractive on paper, their performance leaves much to be desired. The technology may be something that looks better on paper than in the real world …

“Although Germany abandoned this technology, it did migrate to other countries, including China and South Africa. Of these, the latter case is instructive: South Africa pursued the construction of a pebble-bed reactor for a decade, and spent over a billion dollars, only to abandon it in 2009 because it just did not make sense economically. Although sold by its proponents as innovative and economically competitive until its cancellation, the South African pebble-bed reactor project is now being cited as a case study in failure. How good the Chinese experience with the HTGR will be remains to be seen. …

“From these experiences in operating HTGRs, we can take away several lessons – the most important being that HTGRs are prone to a wide variety of small failures, including graphite dust accumulation, ingress of water or oil, and fuel failures. Some of these could be the trigger for larger failures or accidents, with more severe consequences. … Other problems could make the consequences of a severe accident worse: For example, pebble compaction and breakage could lead to accelerated diffusion of fission products such as radioactive cesium and strontium outside the pebbles, and a potentially larger radioactive release in the event of a severe accident. …

“Discussions of the commercial viability of HTGRs almost invariably focus on the expected higher capital costs per unit of generation capacity (dollars per kilowatts) in comparison with light water reactors, and potential ways for lowering those. In other words, the main challenge they foresee is that of building these reactors cheaply enough. But what they implicitly or explicitly assume is that HTGRs would operate as well as current light water reactors – which is simply not the case, if history is any guide. …

“Although there has been much positive promotional hype associated with high-temperature reactors, the decades of experience that researchers have acquired in operating HTGRs has seldom been considered. Press releases from the many companies developing or selling HTGRs or project plans in countries seeking to purchase or construct HTGRs neither tell you that not a single HTGR-termed “commercial” has proven financially viable nor do they mention that all the HTGRs were shut down well before the operating periods envisioned for them. This is typical of the nuclear industry, which practices selective remembrance, choosing to forget or underplay earlier failures.”

M. V. Ramana, April 2016, ‘The checkered operational history of high-temperature gas-cooled reactors’, Bulletin of the Atomic Scientists, http://dx.doi.org/10.1080/00963402.2016.1170395

Accident Scenarios Involving Pebble Bed High Temperature Reactors

Matthias Englert, Friederike Frieß and M. V. Ramana, Feb 2017, ‘Accident Scenarios Involving Pebble Bed High Temperature Reactors’, Science & Global Security, Vol.25 Iss.1, pp.42-55, http://dx.doi.org/10.1080/08929882.2017.1275320

Proponents of high temperature gas cooled reactors argue that the reactor type is inherently safe and that severe accidents with core damage and radioactive releases cannot occur. The argument is primarily based on the safety features of the special form of the fuel. This paper examines some of the assumptions underlying the safety case for high temperature gas cooled reactors and highlights ways in which there could be fuel failure even during normal operations of the reactor; these failures serve to create a radioactive inventory that could be released under accident conditions. It then describes the severe accident scenarios that are the greatest challenge to high temperature gas cooled reactor safety: ingress of air or water into the core. Then, the paper offers an overview of what could be learned from the experiences with high temperature gas cooled reactors that have been built; their operating history indicates differences between actual operations and theoretical behavior. Finally, the paper describes some of the multiple priorities that often drive reactor design, and how safety is compromised in the process of optimizing other priorities.

PEBBLE BED MODULAR REACTORS (PBMR)

2013 summary by Friends of the Earth Australia

Pebble Bed Modular Reactors (PBMR) are helium-cooled and graphite-moderated and intended to be built in small modules (Thomas, 1999; Harding, 2004; Hirsch et al., 2005). Pressurised helium heated in the reactor core drives turbines that attach to an electrical generator.

While the PBMR is in some respects innovative, it also shares features with high temperature gas cooled reactors (HGTR). The HTGR line has been pursued until the late 80s in several countries; however, only prototype plants were ever operated (in the USA, UK and Germany), all of which were decommissioned after about 12 years of operation at most.

A South African nuclear utility has been at the forefront of developing pebble bed reactors but the project was postponed indefinitely as a result of economic factors as well as technical factors, some with safety consequences. Unless the South African project is revived, that leaves only China developing pebble bed concepts (with one small prototype operating and one 200 MW ‘demonstration reactor’ planned or in the early stages of construction).

These articles discuss the demise of PBMR technology in South Africa:

PBMR proponents claim major safety advantages resulting from the heat-resistant quality and integrity of the small fuel pebbles, many thousands of which are continuously fed from a silo. Each spherical fuel element has a graphite core embedded with thousands of small fuel particles of enriched uranium (up to 10% uranium-235), encapsulated in layers of carbon.

The safety advantages of PBMR technology include a greater ability to retain fissile products in the event of a loss-of-coolant accident. While this configuration is potentially advantageous compared to conventional reactors, it does not altogether avoid the risk of serious accidents; in other words, claims that the system is ‘walk-away safe’ are overblown. The safety advantages can be undermined by familiar commercial pressures; for example there are plans to develop PBMR reactors with no containment building.

In relation to weapons proliferation (Harding, 2004):

  • The nature of the fuel pebbles may make it somewhat more difficult to separate plutonium from irradiated fuel, but plutonium separation is certainly not impossible.
  • Uranium (or depleted uranium) targets could be inserted to produce weapon-grade plutonium for weapons, or thorium targets could be inserted to produce uranium-233.
  • The enriched uranium fuel could be further enriched for weapons – particularly since the proposed enrichment level of 9.6% uranium-235 is about twice the level of conventional reactor fuel.
  • The reliance on enriched uranium will encourage the use and perhaps proliferation of enrichment plants, which can be used to produce highly-enriched uranium for weapons.

References:

Harding, Jim, 2004, “Pebble Bed Modular Reactors—Status and Prospects”, www.rmi.org/sitepages/pid171php#E05-10

Hirsch, Helmut, Oda Becker, Mycle Schneider and Antony Froggatt, April 2005, “Nuclear Reactor Hazards: Ongoing Dangers of Operating Nuclear Technology in the 21st Century”, Report prepared for Greenpeace International, www.greenpeace.org/international/press/reports/nuclearreactorhazards

Thomas, Steve, 1999, “Arguments on the Construction of Pebble Bed Modular Reactors in South Africa”, www.sussex.ac.uk/Units/spru/environment/research/pbmr.html

Fast neutron/breeder reactors

2013 Friends of the Earth summary

Fast neutron reactors generally use plutonium as the primary fuel. They do not require a moderator as the fuel fissions sufficiently with fast neutrons to maintain a chain reaction. The various possible configurations include ‘breeders’ which produce more plutonium than they consume, ‘burners’ which do the reverse, and configurations which both breed and burn plutonium. (World Nuclear Association, 2005.)

There are various possible configurations of breeder systems. Most rely on irradiation of a natural or depleted uranium blanket which produces plutonium which can be separated and used as fuel. (Hirsch et al., 2005, pp.33-35; von Hippel and Jones, 1997.)

Small R&D programs are ongoing in a few countries (e.g. India, Russia, France) but in other countries the technology has been stalled or abandoned (e.g. the UK, the US, and Germany) or never developed in the first place. Japan’s plans for breeder reactors have been limited and delayed by accidents including the sodium leak and fire at the experimental Monju reactor in 1995. (Leventhal and Dolley, 1999.)

One reason for the limited interest in plutonium breeder power sources has been the cheap, plentiful supply of uranium. That situation may change, but while breeder technology certainly holds out the promise of successfully addressing the problem of limited conventional uranium reserves, it is doubtful whether the wider range of technical, economic, safety and proliferation issues can be successfully addressed.

Breeder technology is highly problematic in relation to proliferation because it involves the large-scale production and separation of plutonium (although separation is not required in some proposed configurations). (Feiveson, 2001.) The proliferation of reprocessing capabilities is a likely outcome.

Interest in breeder and reprocessing technology in South Korea and China is arguably driven in part by concerns over Japan’s plutonium policies (which involve the large-scale separation and stockpiling of plutonium). (Burnie and Smith, 2001.)

References:

  • Burnie, Shaun and Aileen Mioko Smith, May/June 2001, “Japan’s nuclear twilight zone”, Bulletin of the Atomic Scientists, vol. 57, no.03, pp.58-62, https://www.tandfonline.com/doi/abs/10.1080/00963402.2001.11460458
  • Feiveson, Harold, 2001, “The Search for Proliferation-Resistant Nuclear Power”, The Journal of the Federation of American Scientists, September/October 2001, Volume 54, Number 5, www.fas.org/faspir/2001/v54n5/nuclear.htm
  • Hirsch, Helmut, Oda Becker, Mycle Schneider and Antony Froggatt, April 2005, “Nuclear Reactor Hazards: Ongoing Dangers of Operating Nuclear Technology in the 21st Century”, Report prepared for Greenpeace International, www.greenpeace.org/international/press/reports/nuclearreactorhazards
  • Leventhal, Paul, and Steven Dolley, 1999, “The Reprocessing Fallacy: An Update”, presented to Waste Management 99 Conference, Tucson, Arizona, March 1, 1999, www.nci.org/p/pl-wm99.htm
  • von Hippel, Frank, and Suzanne Jones, 1997, “The slow death of the fast breeder”, Bulletin of the Atomic Scientists, Vol.53, No.5, September/October.
  • World Nuclear Association, 2005, “Fast Neutron Reactors”, http://www.world-nuclear.org/information-library/current-and-future-generation/fast-neutron-reactors.aspx

The slow death of fast reactors

Jim Green, 2 Nov 2016, ‘The slow death of fast reactors’, EnergyPost, energypost.eu/slow-death-fast-reactors/

Generation IV ‘fast breeder’ reactors have long been promoted by nuclear enthusiasts, writes Jim Green, editor of Nuclear Monitor, but Japan’s decision in September to abandon the Monju fast reactor is another nail in the coffin for this failed technology.

Fast neutron reactors are “poised to become mainstream” according to the World Nuclear Association (WNA). But data provided by the WNA itself gives the lie to the claim. The WNA lists eight “current” fast reactors, but one of them hasn’t begun operating, and another (Monju) has just been put out of its misery. Let’s say there are six ‘operable’ fast reactors (one isn’t operating but might in the future ‒ hence the term ‘operable’). Here’s the historical pattern based on WNA tables:

1976 ‒ 7 operable fast reactors
1986 ‒ 11
1996 ‒ 7
2006 ‒ 6
2016 ‒ 6

Of course there’s always tomorrow: the WNA lists 13 fast reactor projects under “active development” for “near- to mid-term deployment”. But a large majority of those 13 projects ‒ perhaps all of them ‒ lack both approval and funding.

Fast reactors aren’t becoming mainstream. One country after another has abandoned the technology. Nuclear physicist Thomas Cochran summarises the history: “Fast reactor development programs failed in the: 1) United States; 2) France; 3) United Kingdom; 4) Germany; 5) Japan; 6) Italy; 7) Soviet Union/Russia 8) U.S. Navy and 9) the Soviet Navy. The program in India is showing no signs of success and the program in China is only at a very early stage of development.”

Japan wastes billions

The latest setback was the decision of the Japanese government at an extraordinary Cabinet meeting on September 21 to abandon plans to restart the Monju fast breeder reactor.

Monju reached criticality in 1994 but was shut down in December 1995 after a sodium coolant leak and fire. The reactor didn’t restart until May 2010, and it was shut down again three months later after a fuel handling machine was accidentally dropped in the reactor during a refuelling outage. In November 2012, it was revealed that Japan Atomic Energy Agency had failed to conduct regular inspections of almost 10,000 out of a total 39,000 pieces of equipment at Monju, including safety-critical equipment.

In November 2015, the Nuclear Regulation Authority declared that the Japan Atomic Energy Agency was “not qualified as an entity to safely operate” Monju. Education minister Hirokazu Matsuno said on 21 September 2016 that attempts to find an alternative operator have been unsuccessful.

The government has already spent 1.2 trillion yen (US$12bn) on Monju. The government calculated that it would cost another 600 billion yen (US$6bn) to restart Monju and keep it operating for another 10 years.

Decommissioning also has a hefty price-tag ‒ far more than for conventional light-water reactors. According to a 2012 estimate by the Japan Atomic Energy Agency, decommissioning Monju will cost an estimated 300 billion yen (US$3bn).

So Japan will have wasted over US$15 billion on the Monju fiasco. Perhaps those responsible will argue that the figure pales into insignificance compared to the estimated long-term costs of around US$500 billion arising from the Fukushima disaster.

Allison MacFarlane, former chair of the US Nuclear Regulatory Commission, recently made this sarcastic assessment of fast reactor technology: “These turn out to be very expensive technologies to build. Many countries have tried over and over. What is truly impressive is that these many governments continue to fund a demonstrably failed technology.”

Japan neatly illustrates MacFarlane’s bemusement. Despite the Monju fiasco, the Japanese government wants to stay involved in the fast reactor game, either by restarting the Joyo experimental fast reactor (shut down since 2007 due to damage to reactor core components) or pursuing joint research with France.

Why would Japan continue its involvement in fast reactors? Most likely, the government has no interest in fast reactors per se, but giving up would make it more difficult to justify continuing with the partially-built Rokkasho reprocessing plant. Providing plutonium fuel for fast reactors was one of the main justifications for Rokkasho.

Rokkasho has been an even more expensive white elephant than Monju. Its scheduled completion in 1997 has been delayed by more than 20 times due to technical glitches and other problems, and its construction cost is now estimated at 2.2 trillion yen (US$22bn) ‒ three times the original estimate.

Japan has wasted around US$37 billion on Monju (US$15bn) and Rokkasho (US$22bn) and plans to continue to throw good money after bad. According to the International Panel on Fissile Materials, if Rokkasho operates it is expected to increase the electricity bills of Japan’s ratepayers by about US$100 billion over the next 40 years.

India’s failed program

India’s fast reactor program has also been a failure. The budget for the Fast Breeder Test Reactor (FBTR) was approved in 1971 but the reactor was delayed repeatedly, attaining first criticality in 1985. It took until 1997 for the FBTR to start supplying a small amount of electricity to the grid. The FBTR’s operations have been marred by several accidents.

Preliminary design work for a larger Prototype Fast Breeder Reactor (PFBR) began in 1985, expenditures on the reactor began in 1987/88 and construction began in 2004 ‒ but the reactor still hasn’t started up. Construction has taken more than twice the expected period. In July 2016, the Indian government announced yet another delay, and there is scepticism that the scheduled start-up in March 2017 will be realised. The PFBR’s cost estimate has gone up by 62%.

India’s Department of Atomic Energy (DAE) has for decades projected the construction of hundreds of fast reactors ‒ for example a 2004 DAE document projected 262.5 gigawatts (GW) of fast reactor capacity by 2050. But India has a track record of making absurd projections for both fast reactors and light-water reactors ‒ and failing to meet those targets by orders of magnitude.

Princeton academic M.V. Ramana writes: “Breeder reactors have always underpinned the DAE’s claims about generating large quantities of electricity. Today, more than six decades after the grand plans for growth were first announced, that promise is yet to be fulfilled. The latest announcement about the delay in the PFBR is yet another reminder that breeder reactors in India, like elsewhere, are best regarded as a failed technology and that it is time to give up on them.”

Russia’s snail-paced program

Russia’s fast reactor program is the only one that could be described as anything other than a failure. But it hasn’t been a roaring success either.

Three fast reactors are in operation in Russia ‒ BOR-60 (start-up in 1969), BN-600 (1980) and BN-800 (2014). There have been 27 sodium leaks in the BN-600 reactor, five of them in systems with radioactive sodium, and 14 leaks were accompanied by burning of sodium.

The Russian government published a decree in August 2016 outlining plans to build 11 new reactors over the next 14 years. Of the 11 proposed new reactors, three are fast reactors: BREST-300 near Tomsk in Siberia, and two BN-1200 fast reactors near Ekaterinburg and Chelyabinsk, near the Ural mountains. However, like India, the Russian government has a track record of projecting rapid and substantial nuclear power expansion ‒ and failing miserably to meet the targets.

As Vladimir Slivyak recently noted in Nuclear Monitor: “While Russian plans look big on paper, it’s unlikely that this program will be implemented. It’s very likely that the current economic crisis, the deepest in history since the USSR collapsed, will axe most of the new reactors.”

While the August 2016 decree signals new interest in reviving the BN-1200 reactor project, it was indefinitely suspended in 2014, with Rosatom citing the need to improve fuel for the reactor and amid speculation about the cost-effectiveness of the project.16

In 2014, Rosenergoatom spokesperson Andrey Timonov said the BN-800 reactor, which started up in 2014, “must answer questions about the economic viability of potential fast reactors because at the moment ‘fast’ technology essentially loses this indicator [when compared with] commercial VVER units.”

China going nowhere fast

Australian nuclear lobbyist Geoff Russell cites the World Nuclear Association (WNA) in support of his claim that China expect fast reactors “to be dominating the market by about 2030 and they’ll be mass produced.”

Does the WNA paper support the claim? Not at all. China has a 20 MWe experimental fast reactor, which operated for a total of less than one month in the 63 months from criticality in July 2010 to October 2015. For every hour the reactor operated in 2015, it was offline for five hours, and there were three recorded reactor trips.

China also has plans to build a 600 MWe ‘Demonstration Fast Reactor’ and then a 1,000 MWe commercial-scale fast reactor. Whether those reactors will be built remains uncertain ‒ the projects have not been approved ‒ and it would be another giant leap from a single commercial-scale fast reactor to a fleet of them.

According to the WNA, a decision to proceed with or cancel the 1,000 MWe fast reactor will not be made until 2020, and if it proceeds, construction could begin in 2028 and operation could begin in about 2034.

So China might have one commercial-scale fast reactor by 2034 ‒ but probably won’t ‒ and Russell’s claim that fast reactors will be “dominating the market by about 2030″ is jiggery-pokery of the highest order and the lowest repute.

According to the WNA, China envisages 40 GW of fast reactor capacity by 2050. A far more likely scenario is that China will have 0 GW of fast reactor capacity by 2050. And even if the 40 GW target was reached, it would still only represent around one-sixth of total nuclear capacity in China in 2050 according to the WNA ‒ fast reactors still wouldn’t be “dominating the market” even if capacity grows 2000-fold from 20 MW (the experimental reactor) to 40 GW.

Travelling-waves and the non-existent ‘integral fast reactor’

Perhaps the travelling-wave fast reactor popularised by Bill Gates will come to the rescue? Or perhaps not. According to the WNA, China General Nuclear Power and Xiamen University are reported to be cooperating on R&D, but the Ministry of Science and Technology, China National Nuclear Corporation, and the State Nuclear Power Technology Company are all skeptical of the travelling-wave reactor concept.

Perhaps the ‘integral fast reactor’ (IFR) championed by James Hansen will come to the rescue? Or perhaps not. The UK and US governments have been considering building IFRs (specifically GE Hitachi’s ‘PRISM’ design) for plutonium disposition ‒ but it is almost certain that both countries will choose different methods to manage plutonium stockpiles.

In South Australia, nuclear lobbyists united behind a push for IFRs/PRISMs, and they would have expected to persuade a stridently pro-nuclear Royal Commission to endorse their ideas. But the Royal Commission completely rejected the proposal, noting in its May 2016 report that advanced fast reactors are unlikely to be feasible or viable in the foreseeable future; that the development of such a first-of-a-kind project would have high commercial and technical risk; that there is no licensed, commercially proven design and development to that point would require substantial capital investment; and that electricity generated from such reactors has not been demonstrated to be cost competitive with current light water reactor designs.

A future for fast reactors?

Just 400 reactor-years of worldwide experience have been gained with fast reactors. There is 42 times more experience with conventional reactors (16,850 reactor-years). And most of the experience with fast reactors suggests they are more trouble than they are worth.

Apart from the countries mentioned above, there is very little interest in pursuing fast reactor technology. Germany, the UK and the US cancelled their prototype breeder reactor programs in the 1980s and 1990s.

France is considering building a fast reactor (ASTRID) despite the country’s unhappy experience with the Phénix and Superphénix reactors. But a decision on whether to construct ASTRID will not be made until 2019/20.

The performance of the Superphénix reactor was as dismal as Monju. Superphénix was meant to be the world’s first commercial fast reactor but in the 13 years of its miserable existence it rarely operated ‒ its ‘Energy Unavailability Factor’ was 90.8% according to the IAEA. Note that the fast reactor lobbyists complain about the intermittency of wind and solar!

A 2010 article in the Bulletin of the Atomic Scientists summarised the worldwide failure of fast reactor technology: “After six decades and the expenditure of the equivalent of about $100 billion, the promise of breeder reactors remains largely unfulfilled. … The breeder reactor dream is not dead, but it has receded far into the future. In the 1970s, breeder advocates were predicting that the world would have thousands of breeder reactors operating this decade. Today, they are predicting commercialization by approximately 2050.”

While fast reactors face a bleak future, the rhetoric will persist. Australian academic Barry Brook wrote a puff-piece about fast reactors for the Murdoch press in 2009. On the same day he said on his website that “although it’s not made abundantly clear in the article”, he expects conventional reactors to play the major role for the next two to three decades but chose to emphasise fast reactors “to try to hook the fresh fish”.

So that’s the nuclear lobbyists’ game plan − making overblown claims about fast reactors and other Generation IV reactor concepts, pretending that they are near-term prospects, and being less than “abundantly clear” about the truth.

Dr Jim Green is the national nuclear campaigner with Friends of the Earth, Australia, and editor of the Nuclear Monitor newsletter published by the World Information Service on Energy.

Fusion

2013 Friends of the Earth summary

Fusion fuel ‒ using different isotopes of hydrogen ‒ must be heated to extreme temperatures of some 100 million degrees Celsius, and must be kept dense enough, and confined for long enough to enable fusion to become self-sustaining.

A major fusion R&D program is underway called the International Thermonuclear Experimental Reactor. (www.iter.org) It involves the European Union, Japan, China, India, South Korea, Russia, and the USA. An experimental plant is under construction at Cadarache in France.

Fusion power remains a distant dream. According to the World Nuclear Association (2005C), fusion “presents so far insurmountable scientific and engineering challenges”.

Australian proponents of fusion claim it is “intrinsically clean” and “inherently safe” (Hole and O’Connor, 2006). However, in relation to radioactive waste issues, the World Nuclear Association (2005C) states: “[A]lthough fusion generates no radioactive fission products or transuranic elements and the unburned gases can be treated on site, there would a short-term radioactive waste problem due to activation products. Some component materials will become radioactive during the lifetime of a reactor, due to bombardment with high-energy neutrons, and will eventually become radioactive waste. The volume of such waste would be similar to that due to activation products from a fission reactor. The radiotoxicity of these wastes would be relatively short-lived compared with the actinides (long-lived alpha-emitting transuranic isotopes) from a fission reactor.”

In relation to safety issues, the World Nuclear Association (2005C) points to potential problems identified by the American Association for the Advancement of Science (AAAS): “These include the hazard arising from an accident to the magnetic system. The total energy stored in the magnetic field would be similar to that of an average lightning bolt (100 billion joules, equivalent to c45 tonnes of TNT). Attention was also drawn to the possibility of a lithium fire. In contact with air or water lithium burns spontaneously and could release many times that amount of energy. Safety of nuclear fusion is a major issue. But the AAAS was most concerned about the release of tritium into the environment. It is radioactive and very difficult to contain since it can penetrate concrete, rubber and some grades of steel. As an isotope of hydrogen it is easily incorporated into water, making the water itself weakly radioactive. With a half-life of 12.4 years, tritium remains a threat to health for over one hundred years after it is created, as a gas or in water. It can be inhaled, absorbed through the skin or ingested. Inhaled tritium spreads throughout the soft tissues and tritiated water mixes quickly with all the water in the body. The AAAS estimated that each fusion reactor could release up to 2×1012 Bequerels of tritium a day during operation through routine leaks, assuming the best containment systems, much more in a year than the Three Mile Island accident released altogether. An accident would release even more. This is one reason why long-term hopes are for the deuterium-deuterium fusion process, dispensing with tritium.”

Some proponents of fusion falsely claim that fusion power systems pose no risk of contributing to the proliferation of nuclear weapons. In fact, there are several risks (Gsponer and Hurni, 2004; WISE/NIRS, 2004; Hirsch et al., 2005):

  • The production or supply of tritium which can be diverted for use in boosted nuclear weapons.
  • Using neutron radiation to bombard a uranium blanket (leading to the production of fissile plutonium) or a thorium blanket (leading to the production of fissile uranium-233).
  • Research in support of a (thermonuclear) weapon program.

Fusion power R&D has already contributed to proliferation problems. According to Khidhir Hamza (1998), a senior nuclear scientist involved in Iraq’s weapons program: “Iraq took full advantage of the IAEA’s recommendation in the mid 1980s to start a plasma physics program for “peaceful” fusion research. We thought that buying a plasma focus device … would provide an excellent cover for buying and learning about fast electronics technology, which could be used to trigger atomic bombs.”

References

  • Gsponer, A., and J-P. Hurni, 2004 “ITER: The International Thermonuclear Experimental Reactor and the Nuclear Weapons Proliferation Implications of Thermonuclear-Fusion Energy Systems”, Independent Scientific Research Institute report number ISRI-04-01, http://arxiv.org/abs/physics/0401110
  • Hamza, Khidhir, 1998, “Inside Saddam’s secret nuclear program”, Bulletin of the Atomic Scientists, September/October, Vol.54, No.5, www.thebulletin.org/article.php?art_ofn=so98hamza
  • Hirsch, Helmut, Oda Becker, Mycle Schneider and Antony Froggatt, April 2005, “Nuclear Reactor Hazards: Ongoing Dangers of Operating Nuclear Technology in the 21st Century”, Report prepared for Greenpeace International, www.greenpeace.org/international/press/reports/nuclearreactorhazards
  • Hole, Matthew and John O’Connor, June 8, 2006, ” Australia needs to get back to the front on fusion power”, www.theage.com.au/news/opinion/we-need-to-get-back-to-the-front-on-fusion/2006/06/07/1149359815047.html
  • WISE/NIRS, February 13, 2004, “The Proliferation Risks of ITER”, WISE/NIRS Nuclear Monitor, #603, https://wiseinternational.org/nuclear-monitor/603/proliferation-risks-iter
  • World Nuclear Association, 2005C, “Nuclear Fusion Power”, http://www.world-nuclear.org/information-library/current-and-future-generation/nuclear-fusion-power.aspx

Fusion scientist debunks fusion power

Nuclear Monitor #842, 26 April 2017, ‘Fusion scientist debunks fusion power’, www.wiseinternational.org/nuclear-monitor/842/fusion-scientist-debunks-fusion-power

The Bulletin of the Atomic Scientists has published a detailed critique of fusion power written by Dr Daniel Jassby, a former principal research physicist at the Princeton Plasma Physics Lab with 25 years experience working in areas of plasma physics and neutron production related to fusion energy.1

Here is a summary of his main arguments.

Jassby writes:

“[U]nlike what happens in solar fusion ‒ which uses ordinary hydrogen ‒ Earth-bound fusion reactors that burn neutron-rich isotopes have byproducts that are anything but harmless: Energetic neutron streams comprise 80 percent of the fusion energy output of deuterium-tritium reactions and 35 percent of deuterium-deuterium reactions.

“Now, an energy source consisting of 80 percent energetic neutron streams may be the perfect neutron source, but it’s truly bizarre that it would ever be hailed as the ideal electrical energy source. In fact, these neutron streams lead directly to four regrettable problems with nuclear energy: radiation damage to structures; radioactive waste; the need for biological shielding; and the potential for the production of weapons-grade plutonium 239 ‒ thus adding to the threat of nuclear weapons proliferation, not lessening it, as fusion proponents would have it.

“In addition, if fusion reactors are indeed feasible ‒ as assumed here ‒ they would share some of the other serious problems that plague fission reactors, including tritium release, daunting coolant demands, and high operating costs. There will also be additional drawbacks that are unique to fusion devices: the use of fuel (tritium) that is not found in nature and must be replenished by the reactor itself; and unavoidable on-site power drains that drastically reduce the electric power available for sale.”

All of these problems are endemic to any type of magnetic confinement fusion or inertial confinement fusion reactor that is fueled with deuterium-tritium or deuterium alone. The deuterium-tritium reaction is favored by fusion developers. Jassby notes that tritium consumed in fusion can theoretically be fully regenerated in order to sustain the nuclear reactions, by using a lithium blanket, but full regeneration is not possible in practice for reasons explained in his article.

Jassby writes: “To make up for the inevitable shortfalls in recovering unburned tritium for use as fuel in a fusion reactor, fission reactors must continue to be used to produce sufficient supplies of tritium ‒ a situation which implies a perpetual dependence on fission reactors, with all their safety and nuclear proliferation problems. Because external tritium production is enormously expensive, it is likely instead that only fusion reactors fueled solely with deuterium can ever be practical from the viewpoint of fuel supply. This circumstance aggravates the problem of nuclear proliferation …”

Weapons proliferation

Fusion reactors could be used to produce plutonium-239 for weapons “simply by placing natural or depleted uranium oxide at any location where neutrons of any energy are flying about” in the reactor interior or appendages to the reaction vessel.

Tritium breeding is not required in systems based on deuterium-deuterium reactions, so all the fusion neutrons are available for any use including the production of plutonium-239 for weapons ‒ hence Jassby’s comment about deuterium-deuterium systems posing greater proliferation risks than deuterium-tritium systems. He writes: “In effect, the reactor transforms electrical input power into “free-agent” neutrons and tritium, so that a fusion reactor fueled with deuterium-only can be a singularly dangerous tool for nuclear proliferation.”

Further, tritium itself is a proliferation risk ‒ it is used to enhance the efficiency and yield of fission bombs and the fission stages of hydrogen bombs in a process known as “boosting”, and tritium is also used in the external neutron initiators for such weapons. “A reactor fueled with deuterium-tritium or deuterium-only will have an inventory of many kilograms of tritium, providing opportunities for diversion for use in nuclear weapons,” Jassby writes.

It isn’t mentioned in Jassby’s article, but fusion has already contributed to proliferation problems even though it has yet to generate a single Watt of useful electricity. According to Khidhir Hamza, a senior nuclear scientist involved in Iraq’s weapons program in the 1980s: “Iraq took full advantage of the IAEA’s recommendation in the mid 1980s to start a plasma physics program for “peaceful” fusion research. We thought that buying a plasma focus device … would provide an excellent cover for buying and learning about fast electronics technology, which could be used to trigger atomic bombs.”2

Other problems

Another problem is the “huge” parasitic power consumption of fusion systems ‒ “they consume a good chunk of the very power that they produce … on a scale unknown to any other source of electrical power.” There are two classes of parasitic power drain ‒ a host of essential auxiliary systems that must be maintained continuously even when the fusion plasma is dormant (of the order of 75‒100 MW), and power needed to control the fusion plasma in magnetic confinement fusion systems or to ignite fuel capsules in pulsed inertial confinement fusion systems (at least 6% of the fusion power generated). Thus a 300 MWt / 120 MWe system barely supplies on-site needs and thus fusion reactors would need to be much larger to overcome this problem of parasitic power consumption.

The neutron radiation damage in the solid vessel wall of a fusion reactor is expected to be worse than in fission reactors because of the higher neutron energies, potentially putting the integrity of the reaction vessel in peril.

Fusion fuel assemblies will be transformed into tons of radioactive waste to be removed annually from each reactor. Structural components would need to be replaced periodically thus generating “huge masses of highly radioactive material that must eventually be transported offsite for burial”, and non-structural components inside the reaction vessel and in the blanket will also become highly radioactive by neutron activation.

Molten lithium presents a fire and explosion hazard, introducing a drawback common to liquid-metal cooled fission reactors.

Tritium leakage is another problem. Jassby writes: “Corrosion in the heat exchange system, or a breach in the reactor vacuum ducts could result in the release of radioactive tritium into the atmosphere or local water resources. Tritium exchanges with hydrogen to produce tritiated water, which is biologically hazardous. Most fission reactors contain trivial amounts of tritium (less than 1 gram) compared with the kilograms in putative fusion reactors. But the release of even tiny amounts of radioactive tritium from fission reactors into groundwater causes public consternation. Thwarting tritium permeation through certain classes of solids remains an unsolved problem.”

Water consumption is another problem. Jassby writes: “In addition, there are the problems of coolant demands and poor water efficiency. A fusion reactor is a thermal power plant that would place immense demands on water resources for the secondary cooling loop that generates steam as well as for removing heat from other reactor subsystems such as cryogenic refrigerators and pumps. … In fact, a fusion reactor would have the lowest water efficiency of any type of thermal power plant, whether fossil or nuclear. With drought conditions intensifying in sundry regions of the world, many countries could not physically sustain large fusion reactors.”

Due to all of the aforementioned problems, and others, “any fusion reactor will face outsized operating costs.” Whereas fission reactors typically require around 500 employees, fusion reactors would require closer to 1,000 employees. Jassby states that it “is inconceivable that the total operating costs of a fusion reactor will be less than that of a fission reactor”.

Jassby concludes:

“To sum up, fusion reactors face some unique problems: a lack of natural fuel supply (tritium), and large and irreducible electrical energy drains to offset. Because 80 percent of the energy in any reactor fueled by deuterium and tritium appears in the form of neutron streams, it is inescapable that such reactors share many of the drawbacks of fission reactors ‒ including the production of large masses of radioactive waste and serious radiation damage to reactor components. …

“If reactors can be made to operate using only deuterium fuel, then the tritium replenishment issue vanishes and neutron radiation damage is alleviated. But the other drawbacks remain—and reactors requiring only deuterium fueling will have greatly enhanced nuclear weapons proliferation potential.”

“These impediments ‒ together with colossal capital outlay and several additional disadvantages shared with fission reactors ‒ will make fusion reactors more demanding to construct and operate, or reach economic practicality, than any other type of electrical energy generator.

“The harsh realities of fusion belie the claims of its proponents of “unlimited, clean, safe and cheap energy.” Terrestrial fusion energy is not the ideal energy source extolled by its boosters, but to the contrary: It’s something to be shunned.”

References:

1. Daniel Jassby, 19 April 2017, ‘Fusion reactors: Not what they’re cracked up to be’, Bulletin of the Atomic Scientists, http://thebulletin.org/fusion-reactors-not-what-they%E2%80%99re-cracked-be10699

2. Khidhir Hamza, Sep/Oct 1998, ‘Inside Saddam’s Secret Nuclear Program’, Bulletin of the Atomic Scientists, Vol. 54, No. 5, www.iraqwatch.org/perspectives/bas-hamza-iraqnuke-10-98.htm

Fusion scientist debunks ITER test reactor

Nuclear Monitor #859, 15 March 2018, ‘Fusion scientist debunks ITER test reactor’, https://www.wiseinternational.org/nuclear-monitor/859/fusion-scientist-debunks-iter-test-reactor

The Guardian’s science correspondent reported on 9 March 2018 that the dream of nuclear fusion is on the brink of being realized according to a major new US initiative that says it will put fusion power on the grid within 15 years.1 Prof Maria Zuber, MIT’s vice-president for research, said that the development could represent a major advance in tackling climate change. “At the heart of today’s news is a big idea ‒ a credible, viable plan to achieve net positive energy for fusion,” she said. “If we succeed, the world’s energy systems will be transformed. We’re extremely excited about this.”

Sadly, is can be said with great confidence that the MIT is talking nonsense. Fusion faces huge ‒ possibly insurmountable ‒ obstacles that won’t be solved with an over-excited MIT media release.

In Nuclear Monitor #8422 we summarized an important critique3 of fusion power concepts by retired fusion scientist Dr Daniel Jassby. He has written another article in the Bulletin of the Atomic Scientists, this one concentrating on the International Thermonuclear Experimental Reactor (ITER) under construction in Cadarache, France.4

Jassby notes that plasma physicists regard ITER as the first magnetic confinement device that can possibly demonstrate a “burning plasma,” where heating by alpha particles generated in fusion reactions is the dominant means of maintaining the plasma temperature. However he sees four “possibly irremediable drawbacks”: electricity consumption, tritium fuel losses, neutron activation, and cooling water demand. 

Electricity consumption: The “massive energy investment” to half-build ITER “has been largely provided by fossil fuels, leaving an unfathomably large ‘carbon footprint’ for site preparation and construction of all the supporting facilities, as well as the reactor itself.” ITER is a test reactor and will never generate electricity so that energy investment will never be repaid.

And when ITER is operating (assuming it reaches that stage), a large power input would be required. For a comparable power-producing reactor, a large power output would be necessary just to break even. Power inputs are required for a host of essential auxiliary systems which must be maintained even when the fusion plasma is dormant. In the case of ITER, that non-interruptible power drain varies between 75 and 110 MW(e). A second category of power drain revolves directly around the plasma itself ‒ for ITER, at least 300 MW(e) will be required for tens of seconds to heat the reacting plasma while during the 400-second operating phase, about 200 MW(e) will be needed to maintain the fusion burn and control the plasma’s stability.

Jassby notes that ITER personnel have corrected misleading claims such as the assertion that “ITER will produce 500 megawatts of output power with an input power of 50 megawatts.” The 500 megawatts of output refers to fusion power (embodied in neutrons and alphas), which has nothing to do with electric power. The input of 50 MW is the heating power injected into the plasma to help sustain its temperature and current, and is only a small fraction of the overall electric input power to the reactor (300‒400 MW(e)).

Tritium: “The most reactive fusion fuel is a 50-50 mixture of the hydrogen isotopes deuterium and tritium; this fuel (often written as “D-T”) has a fusion neutron output 100 times that of deuterium alone and a spectacular increase in radiation consequences. … While fusioneers blithely talk about fusing deuterium and tritium, they are in fact intensely afraid of using tritium for two reasons: First, it is somewhat radioactive, so there are safety concerns connected with its potential release to the environment. Second, there is unavoidable production of radioactive materials as D-T fusion neutrons bombard the reactor vessel, requiring enhanced shielding that greatly impedes access for maintenance and introducing radioactive waste disposal issues.”

Tritium supply is likely to be problematic and expensive: “As ITER will demonstrate, the aggregate of unrecovered tritium may rival the amount burned and can be replaced only by the costly purchase of tritium produced in fission reactors.”

Tritium could be produced in the reactor by absorbing the fusion neutrons in lithium completely surrounding the reacting plasma, but “even that fantasy totally ignores the tritium that’s permanently lost in its globetrotting through reactor subsystems. “

Radioactive waste. “[W]hat fusion proponents are loathe to tell you is that this fusion power is not some benign solar-like radiation but consists primarily (80 percent) of streams of energetic neutrons whose only apparent function in ITER is to produce huge volumes of radioactive waste as they bombard the walls of the reactor vessel and its associated components. … A long-recognized drawback of fusion energy is neutron radiation damage to exposed materials, causing swelling, embrittlement and fatigue. As it happens, the total operating time at high neutron production rates in ITER will be too small to cause even minor damage to structural integrity, but neutron interactions will still create dangerous radioactivity in all exposed reactor components, eventually producing a staggering 30,000 tons of radioactive waste.”

Water consumption: “ITER will demonstrate that fusion reactors would be much greater consumers of water than any other type of power generator, because of the huge parasitic power drains that turn into additional heat that needs to be dissipated on site. … In view of the decreasing availability of freshwater and even cold ocean water worldwide, the difficulty of supplying coolant water would by itself make the future wide deployment of fusion reactors impractical.”

The pumps used to circulate cooling water will require a power supply of as much as 56 MW(e).

Conclusions: Jassby concludes with some critical comments on conventional, fusion and fast breeder reactors:

“Critics charge that international collaboration has greatly amplified the cost and timescale but the $20-to-30 billion cost of ITER is not out of line with the costs of other large nuclear enterprises, such as the power plants that have been approved in recent years for construction in the United States (Summer and Vogtle) and Western Europe (Hinkley and Flamanville), and the US MOX nuclear fuel project in Savannah River. All these projects have experienced a tripling of costs and construction timescales that ballooned from years to decades. The underlying problem is that all nuclear energy facilities ‒ whether fission or fusion ‒ are extraordinarily complex and exorbitantly expensive. …

“ITER will be, manifestly, a havoc-wreaking neutron source fueled by tritium produced in fission reactors, powered by hundreds of megawatts of electricity from the regional electric grid, and demanding unprecedented cooling water resources. Neutron damage will be intensified while the other characteristics will endure in any subsequent fusion reactor that attempts to generate enough electricity to exceed all the energy sinks identified herein.

“When confronted by this reality, even the most starry-eyed energy planners may abandon fusion. Rather than heralding the dawn of a new energy era, it’s likely instead that ITER will perform a role analogous to that of the fission fast breeder reactor, whose blatant drawbacks mortally wounded another professed source of “limitless energy” and enabled the continued dominance of light-water reactors in the nuclear arena.”

References:

1. Hannah Devlin, 9 March 2018, ‘Carbon-free fusion power could be ‘on the grid in 15 years”, www.theguardian.com/environment/2018/mar/09/nuclear-fusion-on-brink-of-being-realised-say-mit-scientists

2. ‘Fusion scientist debunks fusion power’, 26 April 2017, Nuclear Monitor #842, 26/04/2017, www.wiseinternational.org/nuclear-monitor/842/fusion-scientist-debunks-fusion-power

3. Daniel Jassby, 19 April 2017, ‘Fusion reactors: Not what they’re cracked up to be’, Bulletin of the Atomic Scientists, http://thebulletin.org/fusion-reactors-not-what-they%E2%80%99re-cracked-be10699

4. Daniel Jassby, 14 Feb 2018, ‘ITER is a showcase … for the drawbacks of fusion energy’, https://thebulletin.org/iter-showcase-drawbacks-fusion-energy11512

Pyroprocessing: the integral fast reactor waste fiasco

Nuclear Monitor # 849, 25 Aug 2017, ‘Pyroprocessing: the integral fast reactor waste fiasco’, https://www.wiseinternational.org/nuclear-monitor/849/pyroprocessing-integral-fast-reactor-waste-fiasco

In theory, integral fast reactors (IFRs) would gobble up nuclear waste and convert it into low-carbon electricity. In practice, the IFR R&D program in Idaho has left a legacy of troublesome waste. This saga is detailed in a recent article1 and a longer report2 by the Union of Concerned Scientists’ senior scientist Ed Lyman.

Lyman notes that the IFR concept “has attracted numerous staunch advocates” but their “interest has been driven largely by idealized studies on paper and not by facts derived from actual experience.”1 He discusses the IFR prototype built at Idaho ‒ the Experimental Breeder Reactor-II (EBR-II), which ceased operation in 1994 ‒ and subsequent efforts by the Department of Energy (DOE) to treat 26 metric tons of “sodium-bonded” metallic spent fuel from the EBR-II reactor with pyroprocessing, ostensibly to convert the waste to forms that would be safer for disposal in a geological repository. A secondary goal was to demonstrate the viability of pyroprocessing ‒ but the program has instead demonstrated the serious shortcomings of this technology.

Lyman writes:1

“Pyroprocessing is a form of spent fuel reprocessing that dissolves metal-based spent fuel in a molten salt bath (as distinguished from conventional reprocessing, which dissolves spent fuel in water-based acid solutions). Understandably, given all its problems, DOE has been reluctant to release public information on this program, which has largely operated under the radar since 2000.

“The FOIA [Freedom of Information Act] documents we obtained have revealed yet another DOE tale of vast sums of public money being wasted on an unproven technology that has fallen far short of the unrealistic projections that DOE used to sell the project to Congress, the state of Idaho and the public. However, it is not too late to pull the plug on this program, and potentially save taxpayers hundreds of millions of dollars. …

“Pyroprocessing was billed as a simpler, cheaper and more compact alternative to the conventional aqueous reprocessing plants that have been operated in France, the United Kingdom, Japan and other countries.

“Although DOE shut down the EBR-II in 1994 (the reactor part of the IFR program), it allowed work at the pyroprocessing facility to proceed. It justified this by asserting that the leftover spent fuel from the EBR-II could not be directly disposed of in the planned Yucca Mountain repository because of the potential safety issues associated with presence of metallic sodium in the spent fuel elements, which was used to “bond” the fuel to the metallic cladding that encased it. (Metallic sodium reacts violently with water and air.)

“Pyroprocessing would separate the sodium from other spent fuel constituents and neutralize it. DOE decided in 2000 to use pyroprocessing for the entire inventory of leftover EBR-II spent fuel – both “driver” and “blanket” fuel – even though it acknowledged that there were simpler methods to remove the sodium from the lightly irradiated blanket fuel, which constituted nearly 90% of the inventory.

“However, as the FOIA documents reveal in detail, the pyroprocessing technology simply has not worked well and has fallen far short of initial predictions. Although DOE initially claimed that the entire inventory would be processed by 2007, as of the end of Fiscal Year 2016, only about 15% of the roughly 26 metric tons of spent fuel had been processed. Over $210 million has been spent, at an average cost of over $60,000 per kilogram of fuel treated. At this rate, it will take until the end of the century to complete pyroprocessing of the entire inventory, at an additional cost of over $1 billion.

“But even that assumes, unrealistically, that the equipment will continue to be usable for this extended time period. Moreover, there is a significant fraction of spent fuel in storage that has degraded and may not be a candidate for pyroprocessing in any event. …

“What exactly is the pyroprocessing of this fuel accomplishing? Instead of making management and disposal of the spent fuel simpler and safer, it has created an even bigger mess. …

“[P]yroprocessing has taken one potentially difficult form of nuclear waste and converted it into multiple challenging forms of nuclear waste. DOE has spent hundreds of millions of dollars only to magnify, rather than simplify, the waste problem. This is especially outrageous in light of other FOIA documents that indicate that DOE never definitively concluded that the sodium-bonded spent fuel was unsafe to directly dispose of in the first place. But it insisted on pursuing pyroprocessing rather than conducting studies that might have shown it was unnecessary.

“Everyone with an interest in pyroprocessing should reassess their views given the real-world problems experienced in implementing the technology over the last 20 years at INL. They should also note that the variant of the process being used to treat the EBR-II spent fuel is less complex than the process that would be needed to extract plutonium and other actinides to produce fresh fuel for fast reactors. In other words, the technology is a long way from being demonstrated as a practical approach for electricity production.”

References:

1. Ed Lyman / Union of Concerned Scientists, 12 Aug 2017, ‘The Pyroprocessing Files’, http://allthingsnuclear.org/elyman/the-pyroprocessing-files

2. Edwin Lyman, 2017, ‘External Assessment of the U.S. Sodium-Bonded Spent Fuel Treatment Program’, https://s3.amazonaws.com/ucs-documents/nuclear-power/Pyroprocessing/IAEA-CN-245-492%2Blyman%2Bfinal.pdf

Generation IV nuclear waste claims debunked

Nuclear Monitor #866, 24 Sept 2018, ‘Generation IV nuclear waste claims debunked’,

https://www.wiseinternational.org/nuclear-monitor/866/nuclear-monitor-866-24-september-2018

Lindsay Krall and Allison Macfarlane have written an important article in the Bulletin of the Atomic Scientists debunking claims that certain Generation IV reactor concepts promise major advantages with respect to nuclear waste management. Krall is a post-doctoral fellow at the George Washington University. Macfarlane is a professor at the same university, a former chair of the US Nuclear Regulatory Commission from July 2012 to December 2014, and a member of the Blue Ribbon Commission on America’s Nuclear Future from 2010 to 2012.

Krall and Macfarlane focus on molten salt reactors and sodium-cooled fast reactors, and draw on the experiences of the US Experimental Breeder Reactor II and the US Molten Salt Reactor Experiment.

The article abstract notes that Generation IV developers and advocates “are receiving substantial funding on the pretense that extraordinary waste management benefits can be reaped through adoption of these technologies” yet “molten salt reactors and sodium-cooled fast reactors – due to the unusual chemical compositions of their fuels – will actually exacerbate spent fuel storage and disposal issues.”

Here is the concluding section of the article:

“The core propositions of non-traditional reactor proponents – improved economics, proliferation resistance, safety margins, and waste management – should be re-evaluated. The metrics used to support the waste management claims – i.e. reduced actinide mass and total radiotoxicity beyond 300 years – are insufficient to critically assess the short- and long-term safety, economics, and proliferation resistance of the proposed fuel cycles.

“Furthermore, the promised (albeit irrelevant) actinide reductions are only attainable given exceptional technological requirements, including commercial-scale spent fuel treatment, reprocessing, and conditioning facilities. These will create low- and intermediate-level waste streams destined for geologic disposal, in addition to the intrinsic high-level fission product waste that will also require conditioning and disposal.

“Before construction of non-traditional reactors begins, the economic implications of the back end of these non-traditional fuel cycles must be analyzed in detail; disposal costs may be unpalatable. The reprocessing/treatment and conditioning of the spent fuel will entail costs, as will storage and transportation of the chemically reactive fuels. These are in addition to the cost of managing high-activity operational wastes, e.g. those originating from molten salt reactor filter systems. Finally, decommissioning the reactors and processing their chemically reactive coolants represents a substantial undertaking and another source of non-traditional waste. …

“Issues of spent fuel management (beyond temporary storage in cooling pools, aka “wet storage”) fall outside the scope of the NRC’s reactor design certification process, which is regularly denounced by nuclear advocates as narrowly applicable to light water reactor technology and insufficiently responsive to new reactor designs. Nevertheless, new reactor licensing is contingent on broader policies, including the Nuclear Waste Policy Act and the Continued Storage Rule. Those policies are based on the results of radionuclide dispersion models described in environmental impact statements. But the fuel and barrier degradation mechanisms tested in these models were specific to oxide-based spent fuels, which are inert, compared to the compounds that non-traditional reactors will discharge.

“The Continued Storage Rule explicitly excludes most non-oxide fuels, including those from sodium-cooled fast reactors, from the environmental impact statement. Clearly, storage and disposal of non-oxide commercial fuels should require updated assessments and adjudication.

“Finally, treatment of spent fuels from non-traditional reactors, which by Energy Department precedent is only feasible through their respective (re)processing technologies, raises concerns over proliferation and fissile material diversion. Pyroprocessing and fluoride volatility-reductive extraction systems optimized for spent fuel treatment can – through minor changes to the chemical conditions – also extract plutonium (or uranium 233 bred from thorium). Separation from lethal fission products would eliminate the radiological barriers protecting the fuel from intruders seeking to obtain and purify fissile material. Accordingly, cost and risk assessments of predisposal spent fuel treatments must also account for proliferation safeguards.

“Radioactive waste cannot be “burned”; fission of actinides, the source of nuclear heat, inevitably generates fission products. Since some of these will be radiotoxic for thousands of years, these high-level wastes should be disposed of in stable waste forms and geologic repositories. But the waste estimates propagated by nuclear advocates account only for the bare mass of fission products, rather than that of the conditioned waste form and associated repository requirements.

“These estimates further assume that the efficiency of actinide fission will surge, but this actually relies on several rounds of recycling using immature reprocessing technologies. The low- and intermediate-level wastes that will be generated by these activities will also be destined for geologic disposal but have been neglected in the waste estimates. More important, reprocessing remains a security liability of dubious economic benefit, so the apparent need to adopt these technologies simply to prepare non-traditional spent fuels for storage and disposal is a major disadvantage relative to light water reactors. Theoretical burnups for fast and molten salt reactors are too low to justify the inflated back-end costs and risks, the latter of which may include a commercial path to proliferation.

“Reductions in spent fuel volume, longevity, and total radiotoxicity may be realized by breeding and burning fissile material in non-traditional reactors. But those relatively small reductions are of little value in repository planning, so utilization of these metrics is misleading to policy-makers and the general public. We urge policy-makers to critically assess non-traditional fuel cycles, including the feasibility of managing their unusual waste streams, any loopholes that could commit the American public to financing quasi-reprocessing operations, and the motivation to rapidly deploy these technologies. If decarbonization of the economy by 2050 is the end-goal, a more pragmatic path to success involves improvements to light water reactor technologies, adoption of Blue Ribbon Commission recommendations on spent fuel management, and strong incentives for commercially mature, carbon-free energy technologies.”

Lindsay Krall and Allison Macfarlane, 2018, ‘Burning waste or playing with fire? Waste management considerations for non-traditional reactors’, Bulletin of the Atomic Scientists, 74:5, pp.326-334, https://tandfonline.com/doi/10.1080/00963402.2018.1507791

Thorium

See also the Friends of the Earth web-page on thorium and WMD proliferation risks.

2013 Friends of the Earth summary

The use of thorium-232 as a reactor fuel is sometimes suggested as a long-term energy source, partly because of its relative abundance compared to uranium.

Some experience has been gained with the use of thorium in power and research reactors – but far less experience than has been gained with conventional uranium reactors. The Uranium Information Centre (2004) states that: “Much development work is still required before the thorium fuel cycle can be commercialised, and the effort required seems unlikely while (or where) abundant uranium is available.”

According to the World Nuclear Association (2006): “Problems include the high cost of fuel fabrication due partly to the high radioactivity of U-233 which is always contaminated with traces of U-232; the similar problems in recycling thorium due to highly radioactive Th-228, some weapons proliferation risk of U-233; and the technical problems (not yet satisfactorily solved) in reprocessing. Much development work is still required before the thorium fuel cycle can be commercialised, and the effort required seems unlikely while (or where) abundant uranium is available.”

Thorium fuel cycles are promoted on the grounds that they pose less of a proliferation risk compared to conventional reactors. However, whether there is any significant non-proliferation advantage depends on the design of the various thorium-based systems. No thorium system would negate proliferation risks altogether (Friedman, 1997; Feiveson, 2001).

Neutron bombardment of thorium (indirectly) produces uranium-233, a fissile material which can be used in nuclear weapons (1 Significant Quantity of U-233 = 8kg).

The USA has successfully tested weapons using uranium-233 cores, and India may have investigated the military use of thorium/uranium-233 in addition to its civil applications.

The proliferation risk is exacerbated with existing and proposed configurations involving uranium-233 separation from irradiated fuel. As the World Nuclear Association (2006) notes: “Given a start with some other fissile material (U-235 or Pu-239), a breeding cycle similar to but more efficient than that with U-238 and plutonium (in slow-neutron reactors) can be set up. The Th-232 absorbs a neutron to become Th-233 which normally decays to protactinium-233 and then U-233. The irradiated fuel can then be unloaded from the reactor, the U-233 separated from the thorium, and fed back into another reactor as part of a closed fuel cycle.”

(A research reactor in India operates on U-233 fuel extracted from thorium which has been irradiated and bred in another reactor.)

The possible use of highly enriched uranium (HEU) or plutonium to initiate a thorium-232/uranium-233 reaction, or proposed systems using thorium in conjunction with HEU or plutonium as fuel present the risk of diversion of HEU or plutonium for weapons production.

Kang and von Hippel (2001) conclude that “the proliferation resistance of thorium fuel cycles depends very much upon how they are implemented”. For example, the co-production of uranium-232 complicates weapons production but, as Kang and von Hippel note, “just as it is possible to produce weapon-grade plutonium in low-burnup fuel, it is also practical to use heavy-water reactors to produce U-233 containing only a few ppm of U-232 if the thorium is segregated in “target” channels and discharged a few times more frequently than the natural-uranium “driver” fuel.”

One proposed system is an Accelerator Driven Systems (ADS) in which an accelerator produces a proton beam which is targeted at target nuclei (e.g. lead, bismuth) to produce neutrons. The neutrons can be directed to a subcritical reactor containing thorium. ADS systems could reduce but not negate the proliferation risks.

References:

Feiveson, Harold, 2001, “The Search for Proliferation-Resistant Nuclear Power”, The Journal of the Federation of American Scientists, September/October 2001, Volume 54, Number 5, www.fas.org/faspir/2001/v54n5/nuclear.htm

Friedman, John S., 1997, “More power to thorium?”, Bulletin of the Atomic Scientists, Vol. 53, No.5, September/October

Kang, Jungmin, and Frank N. von Hippel, 2001, “U-232 and the Proliferation-Resistance of U-233 in Spent Fuel”, Science & Global Security, Volume 9, pp 1-32, www.princeton.edu/~globsec/publications/pdf/9_1kang.pdf

Uranium Information Centre, 2004, “Thorium”, Nuclear Issues Briefing Paper # 67.

World Nuclear Association, 2006, “Thorium”, http://www.world-nuclear.org/information-library/current-and-future-generation/thorium.aspx

Thorium ‒ a better fuel for nuclear technology?

Dr. Rainer Moormann, ‘Thorium ‒ a better fuel for nuclear technology?’, Nuclear Monitor #858, 1 March 2018.

Dr. Moormann’s article is online at the Nuclear Monitor website.

Thor-bores and uro-sceptics: thorium’s friendly fire

Jim Green, 9 April 2015, ‘Thor-bores and uro-sceptics: thorium’s friendly fire’, Nuclear Monitor #801, www.wiseinternational.org/nuclear-monitor/801/thor-bores-and-uro-sceptics-thoriums-friendly-fire

Many Nuclear Monitor readers will be familiar with the tiresome rhetoric of thorium enthusiasts − let’s call them thor-bores. Their arguments have little merit but they refuse to go away.

Here’s a thor-bore in full flight − a science journalist who should know better:

“Thorium is a superior nuclear fuel to uranium in almost every conceivable way … If there is such a thing as green nuclear power, thorium is it. … For one, a thorium-powered nuclear reactor can never undergo a meltdown. It just can’t. … Thorium is also thoroughly useless for making nuclear weapons. … But wait, there’s more. Thorium doesn’t only produce less waste, it can be used to consume existing waste.”1

Thankfully, there is a healthy degree of scepticism about thorium, even among nuclear industry insiders, experts and enthusiasts (other than the thor-bores themselves, of course). Some of that ‘friendly fire’ is noted here.

Readiness

The World Nuclear Association (WNA) notes that the commercialization of thorium fuels faces some “significant hurdles in terms of building an economic case to undertake the necessary development work.” The WNA states:

“A great deal of testing, analysis and licensing and qualification work is required before any thorium fuel can enter into service. This is expensive and will not eventuate without a clear business case and government support. Also, uranium is abundant and cheap and forms only a small part of the cost of nuclear electricity generation, so there are no real incentives for investment in a new fuel type that may save uranium resources.

“Other impediments to the development of thorium fuel cycle are the higher cost of fuel fabrication and the cost of reprocessing to provide the fissile plutonium driver material. The high cost of fuel fabrication (for solid fuel) is due partly to the high level of radioactivity that builds up in U-233 chemically separated from the irradiated thorium fuel. Separated U-233 is always contaminated with traces of U-232 which decays (with a 69-year half-life) to daughter nuclides such as thallium-208 that are high-energy gamma emitters. Although this confers proliferation resistance to the fuel cycle by making U-233 hard to handle and easy to detect, it results in increased costs. There are similar problems in recycling thorium itself due to highly radioactive Th-228 (an alpha emitter with two-year half life) present.”2

A 2012 report by the UK National Nuclear Laboratory states:

“NNL has assessed the Technology Readiness Levels (TRLs) of the thorium fuel cycle. For all of the system options more work is needed at the fundamental level to establish the basic knowledge and understanding. Thorium reprocessing and waste management are poorly understood. The thorium fuel cycle cannot be considered to be mature in any area.”3

Fiona Rayment from the UK National Nuclear Laboratory states:

“It is conceivable that thorium could be introduced in current generation reactors within about 15 years, if there was a clear economic benefit to utilities. This would be a once-through fuel cycle that would partly realise the strategic benefits of thorium.

“To obtain the full strategic benefit of the thorium fuel cycle would require recycle, for which the technological development timescale is longer, probably 25 to 30 years.

“To develop radical new reactor designs, specifically designed around thorium, would take at least 30 years. It will therefore be some time before the thorium fuel cycle can realistically be expected to make a significant contribution to emissions reductions targets.”4

Thorium is no ‘silver bullet’

Do thorium reactors potentially offer significant advantages compared to conventional uranium reactors?

Nuclear physicist Prof. George Dracoulis states: “Some of the rhetoric associated with thorium gives the impression that thorium is, somehow, magical. In reality it isn’t.”5

The UK National Nuclear Laboratory report argues that thorium has “theoretical advantages regarding sustainability, reducing radiotoxicity and reducing proliferation risk” but that “while there is some justification for these benefits, they are often over stated.” The report further states that the purported benefits “have yet to be demonstrated or substantiated, particularly in a commercial or regulatory environment.”3

The UK National Nuclear Laboratory report is sceptical about safety claims:

“Thorium fuelled reactors have already been advocated as being inherently safer than LWRs [light water reactors], but the basis of these claims is not sufficiently substantiated and will not be for many years, if at all.”3

False distinction

Thor-bores posit a sharp distinction between thorium and uranium. But there is little to distinguish the two. A much more important distinction is between conventional reactor technology and some ‘Generation IV’ concepts − in particular, those based on repeated (or continuous) fuel recycling and the ‘breeding’ of fissile isotopes from fertile isotopes (Th-232>U-233 or U-238>Pu-239).

A report by the Idaho National Laboratory states:

“For fuel type, either uranium-based or thorium-based, it is only in the case of continuous recycle where these two fuel types exhibit different characteristics, and it is important to emphasize that this difference only exists for a fissile breeder strategy. The comparison between the thorium/U-233 and uranium/Pu-239 option shows that the thorium option would have lower, but probably not significantly lower, TRU [transuranic waste] inventory and disposal requirements, both having essentially equivalent proliferation risks.

“For these reasons, the choice between uranium-based fuel and thorium-based fuels is seen basically as one of preference, with no fundamental difference in addressing the nuclear power issues.

“Since no infrastructure currently exists in the U.S. for thorium-based fuels, and processing of thorium-based fuels is at a lower level of technical maturity when compared to processing of uranium-based fuels, costs and RD&D requirements for using thorium are anticipated to be higher.”7

George Dracoulis takes issue with the “particularly silly claim” by a science journalist (and many others) that almost all the thorium is usable as fuel compared to just 0.7% of uranium (i.e. uranium-235), and that thorium can therefore power civilization for millennia. Dracoulis states:

“In fact, in that sense, none of the thorium is usable since it is not fissile. The comparison should be with the analogous fertile isotope uranium-238, which makes up nearly 100% of natural uranium. If you wanted to go that way (breeding that is), there is already enough uranium-238 to ‘power civilization for millennia’.”5

Some Generation IV concepts promise major advantages, such as the potential to use long-lived nuclear waste and weapons-usable material (esp. plutonium) as reactor fuel. On the other hand, Generation IV concepts are generally those that face the greatest technical challenges and are the furthest away from commercial deployment; and they will gobble up a great deal of R&D funding before they gobble up any waste or weapons material.

Moreover, uranium/plutonium fast reactor technology might more accurately be described as failed Generation I technology. The first reactor to produce electricity − the EBR-I fast reactor in the US, a.k.a. Zinn’s Infernal Pile − suffered a partial fuel meltdown in 1955. The subsequent history of fast reactors has largely been one of extremely expensive, underperforming and accident-prone reactors which have contributed far more to WMD proliferation problems than to the resolution of those problems.

Most importantly, whether Generation IV concepts deliver on their potential depends on a myriad of factors − not just the resolution of technical challenges. India’s fast reactor / thorium program illustrates how badly things can go wrong, and it illustrates problems that can’t be solved with technical innovation. John Carlson, a nuclear advocate and former Director-General of the Australian Safeguards and Non-Proliferation Office, writes:

“India has a plan to produce [weapons-grade] plutonium in fast breeder reactors for use as driver fuel in thorium reactors. This is problematic on non-proliferation and nuclear security grounds. Pakistan believes the real purpose of the fast breeder program is to produce plutonium for weapons (so this plan raises tensions between the two countries); and transport and use of weapons-grade plutonium in civil reactors presents a serious terrorism risk (weapons-grade material would be a priority target for seizure by terrorists).”8

Generation IV thorium concepts such as molten salt reactors (MSR) have a lengthy, uncertain R&D road ahead of them − notwithstanding the fact that there is some previous R&D to build upon.4,9

Kirk Sorensen, founder of a US firm which aims to build a demonstration ‘liquid fluoride thorium reactor’ (a type of MSR), notes that “several technical hurdles” confront thorium-fuelled MSRs, including materials corrosion, reactor control and in-line processing of the fuel.4

George Dracoulis writes:

“MSRs are not currently available at an industrial scale, but test reactors with different configurations have operated for extended periods in the past. But there are a number of technical challenges that have been encountered along the way. One such challenge is that the hot beryllium and lithium “salts” – in which the fuel and heavy wastes are dissolved – are highly reactive and corrosive. Building a large-scale system that can operate reliably for decades is non-trivial. That said, many of the components have been the subject of extensive research programs.”10

Weapons proliferation

Claims that thorium reactors would be proliferation-resistant or proliferation-proof do not stand up to scrutiny.11 Irradiation of thorium-232 produces uranium-233, which can be and has been used in nuclear weapons.

The World Nuclear Association states:

“The USA produced about 2 tonnes of U-233 from thorium during the ‘Cold War’, at various levels of chemical and isotopic purity, in plutonium production reactors. It is possible to use U-233 in a nuclear weapon, and in 1955 the USA detonated a device with a plutonium-U-233 composite pit, in Operation Teapot. The explosive yield was less than anticipated, at 22 kilotons. In 1998 India detonated a very small device based on U-233 called Shakti V.”2

According to Assoc. Prof. Nigel Marks, both the US and the USSR tested uranium-233 bombs in 1955.6

Uranium-233 is contaminated with uranium-232 but there are ways around that problem. Kang and von Hippel note:

“[J]ust as it is possible to produce weapon-grade plutonium in low-burnup fuel, it is also practical to use heavy-water reactors to produce U-233 containing only a few ppm of U-232 if the thorium is segregated in “target” channels and discharged a few times more frequently than the natural-uranium “driver” fuel.”12

John Carlson discusses the proliferation risks associated with thorium:

“The thorium fuel cycle has similarities to the fast neutron fuel cycle – it depends on breeding fissile material (U-233) in the reactor, and reprocessing to recover this fissile material for recycle. …

“Proponents argue that the thorium fuel cycle is proliferation resistant because it does not produce plutonium. Proponents claim that it is not practicable to use U-233 for nuclear weapons.

“There is no doubt that use of U-233 for nuclear weapons would present significant technical difficulties, due to the high gamma radiation and heat output arising from decay of U-232 which is unavoidably produced with U-233. Heat levels would become excessive within a few weeks, degrading the high explosive and electronic components of a weapon and making use of U‑233 impracticable for stockpiled weapons. However, it would be possible to develop strategies to deal with these drawbacks, e.g. designing weapons where the fissile “pit” (the core of the nuclear weapon) is not inserted until required, and where ongoing production and treatment of U-233 allows for pits to be continually replaced. This might not be practical for a large arsenal, but could certainly be done on a small scale.

“In addition, there are other considerations. A thorium reactor requires initial core fuel – LEU or plutonium – until it reaches the point where it is producing sufficient U-233 for self-sustainability, so the cycle is not entirely free of issues applying to the uranium fuel cycle (i.e. requirement for enrichment or reprocessing). Further, while the thorium cycle can be self-sustaining on produced U‑233, it is much more efficient if the U-233 is supplemented by additional “driver” fuel, such as LEU or plutonium. For example, India, which has spent some decades developing a comprehensive thorium fuel cycle concept, is proposing production of weapons grade plutonium in fast breeder reactors specifically for use as driver fuel for thorium reactors. This approach has obvious problems in terms of proliferation and terrorism risks.

“A concept for a liquid fuel thorium reactor is under consideration (in which the thorium/uranium fuel would be dissolved in molten fluoride salts), which would avoid the need for reprocessing to separate U-233. If it proceeds, this concept would have non-proliferation advantages.

“Finally, it cannot be excluded that a thorium reactor – as in the case of other reactors – could be used for plutonium production through irradiation of uranium targets.

“Arguments that the thorium fuel cycle is inherently proliferation resistant are overstated. In some circumstances the thorium cycle could involve significant proliferation risks.”13

Sometimes thor-bores posit conspiracy theories. Former International Atomic Energy Agency Director-General Hans Blix said “it is almost impossible to make a bomb out of thorium” and thorium is being held back by the “vested interests” of the uranium-based nuclear industry.14

But Julian Kelly from Thor Energy, a Norwegian company developing and testing thorium-plutonium fuels for use in commercial light water reactors, states:

“Conspiracy theories about funding denials for thorium work are for the entertainment sector. A greater risk is that there will be a classic R&D bubble [that] divides R&D effort and investment into fragmented camps and feifdoms.”4

Thor-bores and uro-sceptics

Might the considered opinions of nuclear insiders, experts and enthusiasts help to shut the thor-bores up? Perhaps not − critics are dismissed with claims that they have ideological or financial connections to the vested interests of the uranium-based nuclear industry, or they are dismissed with claims that they are ideologically opposed to all things nuclear. But we live in hope.

Thor-bores do serve one useful purpose − they sometimes serve up pointed criticisms of the uranium fuel cycle. In other words, some thor-bores are uro-sceptics. For example, thorium enthusiast and former Shell executive John Hofmeister states:

“The days of nuclear power based upon uranium-based fission are coming to a close because the fear of nuclear proliferation, the reality of nuclear waste and the difficulty of managing it have proven too difficult over time.”15

References:

1. Tim Dean, 16 March 2011, ‘The greener nuclear alternative’, www.abc.net.au/unleashed/45178.html

2. www.world-nuclear.org/info/Current-and-Future-Generation/Thorium/

3. UK National Nuclear Laboratory Ltd., 5 March 2012, ‘Comparison of thorium and uranium fuel cycles’, www.decc.gov.uk/assets/decc/11/meeting-energy-demand/nuclear/6300-comparison-fuel-cycles.pdf

4. Stephen Harris, 9 Jan 2014, ‘Your questions answered: thorium-powered nuclear’, www.theengineer.co.uk/energy-and-environment/in-depth/your-questions-answered-thorium-powered-nuclear/1017776.article

5. George Dracoulis, 5 Aug 2011, ‘Thorium is no silver bullet when it comes to nuclear energy, but it could play a role’, http://theconversation.com/thorium-is-no-silver-bullet-when-it-comes-to-nuclear-energy-but-it-could-play-a-role-1842

6. Nigel Marks, 2 March 2015, ‘Should Australia consider thorium nuclear power?’, http://theconversation.com/should-australia-consider-thorium-nuclear-power-37850

7. Idaho National Laboratory, Sept 2009, ‘AFCI Options Study’, INL/EXT-10-17639, www.inl.gov/technicalpublications/Documents/4480296.pdf

8. John Carlson, 2014, submission to Joint Standing Committee on Treaties, Parliament of Australia, www.aph.gov.au/DocumentStore.ashx?id=79a1a29e-5691-4299-8923-06e633780d4b&subId=301365

9. Oliver Tickell, August/September 2012, ‘Thorium: Not ‘green’, not ‘viable’, and not likely’, www.no2nuclearpower.org.uk/nuclearnews/NuClearNewsNo43.pdf

10. George Dracoulis, 19 Dec 2011, ‘Thoughts from a thorium ‘symposium”, http://theconversation.com/thoughts-from-a-thorium-symposium-4545

11. www.foe.org.au/anti-nuclear/issues/nfc/power-weapons/thorium

12. Jungmin Kang and Frank N. von Hippel, 2001, “U-232 and the Proliferation-Resistance of U-233 in Spent Fuel”, Science & Global Security, Volume 9, pp.1-32, www.princeton.edu/sgs/publications/sgs/pdf/9_1kang.pdf

13. John Carlson, 2009, ‘Introduction to the Concept of Proliferation Resistance’, www.foe.org.au/sites/default/files/Carlson%20ASNO%20ICNND%20Prolif%20Resistance.doc

14. Herman Trabish, 10 Dec 2013, ‘Thorium Reactors: Nuclear Redemption or Nuclear Hazard?’, http://theenergycollective.com/hermantrabish/314771/thorium-reactors-nuclear-redemption-or-nuclear-hazard

15. Pia Akerman, 7 Oct 2013, ‘Ex-Shell boss issues nuclear call’, The Australian, www.theaustralian.com.au/national-affairs/policy/ex-shell-boss-issues-nuclear-call/story-e6frg6xf-1226733858032

A thought for thorium

Nuclear Engineering International, 03 November 2009

www.neimagazine.com/story.asp?sectionCode=76&storyCode=2054564

The question of thorium fuel comes up every so often, says [Albert Machiels, senior technical executive at the USA’s Electric Power Research Institute]. “I really cannot claim that there is a great interest in thorium fuel – it is more a matter of curiosity. …

Experts disagree about whether thorium fuel is more proliferation-resistant than uranium. …

Many in the industry remain sceptical with regard to thorium. Now that uranium infrastructure is in place, developing a thorium fuel cycle is a  ‘big risk,’ ‘unnecessary’ and a ‘distraction,’ according to some in the industry.

I put the question to Thorium Power; if thorium fuel is so good why aren’t we using it? Their response:

“Essentially the answer is because the nuclear industry started using UO2 on a large scale first and they’ve had 50 years to improve it and become comfortable with it. Due to a highly conservative nature of nuclear utilities (‘why change something that works just fine’), there has been little incentive for a commercial utility to switch from UO2 fuels even though ThO2-based fuels have many advantages.”

For this reason, if thorium fuel is going to take off it will need to be introduced in light water reactors first, notwithstanding the interesting reactor concepts currently being developed that use thorium. In accelerator-driven systems, or ADS, a particle accelerator knocks neutrons off a heavy element such as mercury, and those neutrons cause thorium to breed fissile uranium- 233. In molten salt reactors, thorium dissolved in a 650°C fluoride salt coolant breeds uranium-233, which undergoes fission.

“ADS and breeder reactors, such as molten-salt reactors, are so far in the future that if thorium has to wait for one of those developments it’s not going to happen. The point of entry must be the existing infrastructure, at least for the United States,” Machiels says.

Comparison of thorium and uranium fuel cycles

UK National Nuclear Laboratory Ltd.

A report prepared for and on behalf of Department of Energy and Climate Change

Issue 5, 5 Mar 2012

http://www.decc.gov.uk/assets/decc/11/meeting-energy-demand/nuclear/6300-comparison-fuel-cycles.pdf

EXECUTIVE SUMMARY

The UK National Nuclear Laboratory has been contracted by the Department for Energy and Climate Change (DECC) to review and assess the relevance to the UK of the advanced reactor systems currently being developed internationally. Part of the task specification relates to comparison of the thorium and uranium fuel cycles. Worldwide, there has for a long time been a sustained interest in the thorium fuel cycle and presently there are several major research initiatives which are either focused specifically on the thorium fuel cycle or on systems which use thorium as the fertile seed instead of U-238. Currently in the UK, the thorium fuel cycle is not an option that is being pursued commercially and it is important for DECC to understand why this is the case and whether there is a valid argument for adopting a different position in the future.

NNL has recently published a position paper on thorium [1] which attempts to take a balanced view of the relative advantages and disadvantages of the thorium fuel cycle. Thorium has theoretical advantages regarding sustainability, reducing radiotoxicity and reducing proliferation risk. NNL’s position paper finds that while there is some justification for these benefits, they are often over stated.

The value of using thorium fuel for plutonium disposition would need to be assessed against high level issues concerning the importance of maintaining high standards of safety, security and protection against proliferation, as well as meeting other essential strategic goals related to maintaining flexibility in the fuel cycle, optimising waste arisings and economic competitiveness. It is important that the UK should be very clear as to what the overall objectives should be and the timescales for achieving these objectives.

Overall, the conclusion is reached that the thorium fuel cycle at best has only limited relevance to the UK as a possible alternative plutonium disposition strategy and as a possible strategic option in the very long term for any follow-up reactor construction programme after LWR new build. Nevertheless, it is important to recognise that world-wide there remains interest in thorium fuel cycles and as this is not likely to diminish in the near future. It may therefore be judicious for the UK to maintain a low level of engagement in thorium fuel cycle R&D by involvement in international collaborative research activities. This will enable the UK to keep up with developments, comment from a position of knowledge and to some extent influence the direction of research. Participation will also ensure that the UK is more ready to respond if changes in technology or market forces bring the thorium fuel cycle more to the fore.

Important French and US government reports pouring cold water on Gen 4 propaganda

US Government Accountability Office pours cold water on advanced reactor concepts

Nuclear Monitor #810, 9 Sept 2015, ‘US Government Accountability Office pours cold water on advanced reactor concepts’, https://www.wiseinternational.org/nuclear-monitor/810/us-government-accountability-office-pours-cold-water-advanced-reactor-concepts

The US Government Accountability Office (GAO) has released a report on the status of small modular reactors (SMRs) and other new reactor concepts in the US.

Let’s begin with the downbeat conclusion of the GAO report:

“While light water SMRs and advanced reactors may provide some benefits, their development and deployment face a number of challenges. Both SMRs and advanced reactors require additional technical and engineering work to demonstrate reactor safety and economics, although light water SMRs generally face fewer technical challenges than advanced reactors because of their similarities to the existing large LWR [light water] reactors. Depending on how they are resolved, these technical challenges may result in higher-cost reactors than anticipated, making them less competitive with large LWRs or power plants using other fuels. …

“Both light water SMRs and advanced reactors face additional challenges related to the time, cost, and uncertainty associated with developing, certifying or licensing, and deploying new reactor technology, with advanced reactor designs generally facing greater challenges than light water SMR designs. It is a multi-decade process, with costs up to $1 billion to $2 billion, to design and certify or license the reactor design, and there is an additional construction cost of several billion dollars more per power plant.

“Furthermore, the licensing process can have uncertainties associated with it, particularly for advanced reactor designs. A reactor designer would need to obtain investors or otherwise commit to this development cost years in advance of when the reactor design would be certified or available for licensing and construction, making demand (and customers) for the reactor uncertain. For example, the price of competing power production facilities may make a nuclear plant unattractive without favorable rates set by a public authority or long term prior purchase agreements, and accidents such as Fukushima as well as the ongoing need for a long-term solution for spent nuclear fuel may affect the public perception of reactor safety. These challenges will need to be addressed if the capabilities and diversification of energy sources that light water SMRs and advanced reactors can provide are to be realized.”

Many of the same reasons explain the failure of the Next Generation Nuclear Plant Project. Under the Energy Policy Act of 2005, the US Department of Energy (DoE) was to deploy a prototype ‘next generation’ reactor using advanced technology to generate electricity, produce hydrogen, or both, by the end of fiscal year 2021. However, in 2011, DoE decided not to proceed with the deployment phase of the project.

Small modular reactors

Four companies have considered developing SMRs in the US in recent years. NuScale has a cost-sharing agreement such that the DoE will pay as much as half of NuScale’s costs − up to $217 million (€194m) over five years − for SMR design certification. NuScale expects to submit a design certification application to NRC in late 2016, and may begin operating its first SMR in 2023 or 2024. (However the timeframe is unrealistic, and the project may be abandoned − as other SMR projects have.)

The other three companies are a long way behind NuScale:

  • mPower, a subsidiary of Babcock & Wilcox, enjoyed a cost-sharing agreement with the DoE but in 2014 scaled back its R&D efforts because of a lack of committed customers and a lack of investors.
  • Holtec says it is continuing R&D work, but does not have a detailed schedule.
  • In 2014 Westinghouse suspended its efforts to certify its SMR design, because of a lack of committed customers (and the lack of a DoE cost-sharing agreement).

The GAO report states that the development of light water SMRs may proceed without serious difficulties as they are based on existing light water reactor technology. That said, standardization is a key pillar of SMR rhetoric, and members of an expert group convened by the GAO noted that component standardization has proven challenging for the construction of the larger Westinghouse AP1000 that has some modular components.

Another pillar of SMR rhetoric is mass production (to make them economic), and the development of a massive construction chain to allow for mass production is a radically different proposition to NuScale’s plan to build just one reactor over the next decade.

Not-so-advanced reactor concepts

According to the GAO report, SMRs and new reactor concepts “face some common challenges such as long time frames and high costs associated with the shift from development to deployment − that is, in the construction of the first commercial reactors of a particular type.”

The report notes the US government’s generous financial support for utilities developing SMRs and advanced reactor concepts − DoE provided US$152.5 million (€137m) in fiscal year 2015 alone. Advanced reactor concepts attracting DoE largesse are the high temperature gas cooled reactor, the sodium cooled fast reactor, and to a lesser extent the molten salt reactor (specifically, a sub-type known as the fluoride salt cooled high temperature reactor).

DoE and Nuclear Regulatory Commission (NRC) officials do not expect applications for advanced reactors for at least five years. In other words, an application may (or may not) be submitted some time between five years and five centuries from now.

Advanced reactor designers told the GAO that they have been challenged to find investors due to the lengthy timeframe, costs, and uncertainty. Advanced reactor concepts face greater technical challenges than light water SMRs because of fundamental design differences. Thus designers have significantly more R&D issues to resolve, including in areas such as materials studies and fuel certification, coolant chemistry studies, and safety analysis. Some members of the expert group convened by the GAO noted a potential need for new test facilities to support this work. Furthermore, according to reactor designers, certifying or licensing an advanced reactor may be particularly time-consuming and difficult, adding to the already considerable economic uncertainty for the applicants.

The process of developing and certifying a specific reactor design can take 10 years or more for design work and nearly 3.5 years, as a best case, for NRC certification. Even that timeframe is more hope than expectation. Recent light water reactor design certifications, for the Westinghouse AP1000 and the GE Hitachi ESBWR, have taken about 15 and 11 years respectively. Both the AP1000 and ESBWR are modifications of long-established reactor types, so considerably longer timeframes can be expected for advanced concepts.

The cost to develop and certify a design can range from US$1−2 billion (€0.9−1.8b). Developers hope that costs can be reduced as they move from certification to the construction of a first-of-a-kind plant to the construction of multiple plants. But the GAO report notes that those hopes may be unfounded:

“[S]ome studies suggest that existing, large LWRs have not greatly benefitted from industry-wide standardization or learning to date for reasons including intermittent development and production. In fact, some studies have found that “reverse or negative learning” occurs when increased complexity or operation experience leads to newer safety standards. On a related point, another reactor designer said that the cost and schedule difficulties associated with building the first new design that has been certified by the NRC and started construction in the United States in three decades − the Westinghouse AP1000, a recently designed large LWR − have made it harder for light water SMRs to obtain financing because high-profile problems have made nuclear reactors in general less attractive. … The AP1000 was the first new design that has been certified by the NRC and started construction in the United States in three decades. However, construction problems, including supply chain and regulatory issues, have resulted in cost and schedule increases.”

US Government Accountability Office, July 2015, ‘Nuclear Reactors: Status and challenges in development and deployment of new commercial concepts’, GAO-15-652, www.gao.gov/assets/680/671686.pdf

(Written by Nuclear Monitor editor Jim Green.)


French government agency sceptical about Gen IV reactors

Nuclear Monitor #803, 7 May 2015, ‘French government agency sceptical about Gen IV reactors’, https://www.wiseinternational.org/nuclear-monitor/803/french-government-agency-sceptical-about-gen-iv-reactors

The French Institute for Radiological Protection and Nuclear Safety (IRSN) has produced an important critique of Generation IV nuclear power concepts.1 IRSN is a government authority with 1,790 staff under the joint authority of the Ministries of Defense, the Environment, Industry, Research, and Health.

There are numerous critical analyses of Generation IV concepts by independent experts2, but the IRSN critique is the first from the government of a country with an extensive nuclear industry.

The IRSN report focuses on the six Generation IV concepts prioritised by the Generation IV International Forum (GIF), which brings together 12 countries with an interest in new reactor types, plus Euratom. France is itself one of the countries involved in the GIF.

The six concepts prioritised by the GIF are:

  • Sodium cooled Fast Reactors (SFR);
  • Very High Temperature Reactors, with thermal neutron spectrum (VHTR);
  • Gas-cooled Fast Reactors (GFR);
  • Lead-cooled Fast Reactors (LFR) or Lead-Bismuth (LB) cooled Fast Reactors;
  • Molten Salt Reactors (MSR), with fast or thermal neutron spectrum; and
  • SuperCritical Water Reactors (SCWR), with fast or thermal neutron spectrum.

The report states: “There is still much R&D to be done to develop the Generation IV nuclear reactors, as well as for the fuel cycle and the associated waste management which depends on the system chosen.”

IRSN considers the SFR system to be the only one to have reached a degree of maturity compatible with the construction of a reactor prototype during the first half of this century − and even the development of an SFR prototype would require further preliminary studies and technological developments.

Only SFR and VHTR systems can boast operating experience. IRSN states: “No operating experience feedback from the other four systems studied can be put to direct use. The technological difficulties involved rule out any industrial deployment of these systems within the time frame considered [mid century].”

The report says that for LFR and GFR systems, small prototypes might be built by mid-century. For MSR and SCWR systems, there “is no likelihood of even an experimental or prototype MSR or SCWR being built during the first half of this century” and “it seems hard to imagine any reactor being built before the end of the century”.

IRSN notes that it is difficult to thoroughly evaluate safety and radiation protection standards of Generation IV systems as some concepts have already been partially tried and tested, while others are still in the early stages of development.

IRSN is sceptical about safety claims: “At the present stage of development, IRSN does not notice evidence that leads to conclude that the systems under review are likely to offer a significantly improved level of safety compared with Generation III reactors, except perhaps for the VHTR …” Moreover the VHTR system could bring about significant safety improvements “but only by significantly limiting unit power”.

The report notes that the safety of fast reactors can be problematic because of high operating temperatures and the toxicity and corrosive nature of most coolants considered. It says that issues arising from the Fukushima disaster require detailed examination, such as: choice of coolant; operating temperatures and power densities (which are generally higher for Generation IV concepts); and in some cases, fuel reprocessing facilities that present the risk of toxic releases.

The report is unenthusiastic about research into transmutation of minor actinides (long-lived waste products in spent fuel), saying that “this option offers only a very slight advantage in terms of inventory reduction and geological waste repository volume when set against the induced safety and radiation protection constraints for fuel cycle facilities, reactors and transport.” It notes that ASN, the French nuclear safety authority, has recently announced that minor actinide transmutation would not be a deciding factor in the choice of a future reactor system.

The reports findings on the six GIF concepts are briefly summarised here:

Sodium-cooled Fast Reactors (SFR)

The main safety advantage is the use of low-pressure liquid coolant. The normal operating temperature of this coolant is significantly lower than its boiling point, allowing a grace period of several hours during loss-of-cooling events. The advantage gained from the high boiling point of sodium, however, must be weighed against the fact that the structural integrity of the reactor cannot be guaranteed near this temperature.

The use of sodium also comes with a number of drawbacks due to its high reactivity not only with water and air, but also with MOX fuel.

It seems possible for SFR technology to reach a safety level at least equivalent to that of Generation III pressurised water reactors, but IRSN is unable to determine whether it could significantly exceed this level, in view of design differences and the current state of knowledge and research.

Very High Temperature Reactors (VHTR)
The VHTR benefits from the operating experience feedback obtained from High Temperature Reactors (HTR).
This technology is intrinsically safe with respect to loss of cooling, which means that it could be used to design a reactor that does not require an active decay heat removal system. The VHTR system could therefore bring about significant safety improvements compared with Generation III reactors, especially regarding core melt prevention.

VHTR safety performance can only be guaranteed by significantly limiting unit power.

The feasibility of the system has yet to be determined and will chiefly depend on the development of fuels and materials capable of withstanding high temperatures; the currently considered operating temperature of around 1000°C is close to the transformation temperature of materials commonly used in the nuclear industry.

Lead-cooled Fast Reactors (LFR)

Unlike sodium, lead does not react violently with water or air.

The thermal inertia associated with the large volume of lead used and its very high density results in long grace periods in the event of loss of cooling.

In addition, the high boiling point at atmospheric pressure is a guarantee of high margins under normal operating conditions and rules out the risk of coolant boiling.

The main drawback of lead-cooled (or lead-bismuth cooled) reactors is that the coolant tends to corrode and erode stainless steel structures.

LFR safety is reliant on operating procedures, which does not seem desirable in a Generation IV reactor.

The highly toxic nature of lead and its related products, especially polonium-210, produced when lead-bismuth is used, raises the problem of potential environmental impact.
IRSN is unable to determine whether the LFR system could guarantee a significantly higher safety level than Generation III reactors.

Various technical hurdles need to be overcome before a reactor of this type could be considered.

Gas-cooled Fast Reactors (GFR)

Given the current state of GFR development, construction of an industrial prototype reactor would not be technically feasible. GFR specifications are highly ambitious and raise a number of technological problems that are still a long way from being solved.

From the safety point of view, the GFR does not display any intrinsic quality likely to lead to a significant improvement over Generation III reactors.

Molten Salt Reactors (MSR)

The MSR differs considerably from the other systems proposed by the GIF. The main differences are that the coolant and fuel are mixed in some models and that liquid fuel is used.

The MSR has several advantages, including its burning, breeding and actinide-recycling capabilities.

Its intrinsic neutron properties could be put to good use as, in theory, they should allow highly stable reactor operation. The very low thermal inertia of salt and very high operating temperatures of the system, however, call for the use of fuel salt drainage devices. System safety depends mainly on the reliability and performance of these devices.

Salt has some drawbacks − it is corrosive and has a relatively high crystallisation temperature.

The reactor must also be coupled to a salt processing unit and the system safety analysis must take into account the coupling of the two facilities.

Consideration must be given to the high toxicity of some salts and substances generated by the processes used in the salt processing unit.

The feasibility of fuel salt processing remains to be demonstrated.

SuperCritical-Water-cooled Reactors (SCWR)

The SCWR is the only system selected by GIF that uses water as a coolant. The SCWR is seen as a further development of existing water reactors and thus benefits from operating experience feedback, especially from boiling water reactors. Its chief advantage is economic.

While the use of supercritical water avoids problems relating to the phase change from liquid to vapour, it does not present any intrinsic advantage in terms of safety.

Thermal inertia is very low, for example, when the reactor is shut down.

The use of supercritical water in a nuclear reactor raises many questions, in particular its behaviour under neutron flux.

At the current stage of development, it is impossible to ascertain whether the system will eventually become significantly safer than Generation III reactors.

References:

1. IRSN, 2015, ‘Review of Generation IV Nuclear Energy Systems’, www.irsn.fr/EN/newsroom/News/Pages/20150427_Generation-IV-nuclear-energy-systems-safety-potential-overview.aspx

Direct download: www.irsn.fr/EN/newsroom/News/Documents/IRSN_Report-GenIV_04-2015.pdf

2. See for example: International Panel on Fissile Materials, 2010, ‘Fast Breeder Reactor Programs: History and Status’, www.ipfmlibrary.org/rr08.pdf

Helmut Hirsch, Oda Becker, Mycle Schneider and Antony Froggatt, April 2005, ‘Nuclear Reactor Hazards: Ongoing Dangers of Operating Nuclear Technology in the 21st Century’, www.greenpeace.org/international/press/reports/nuclearreactorhazards

OECD: Generation IV R&D “a growing challenge”

Nuclear Monitor #860, 10 May 2018, ‘Generation IV R&D “a growing challenge”‘, https://www.wiseinternational.org/nuclear-monitor/860/nuclear-news-nuclear-monitor-860-10-may-2018

The OECD Nuclear Energy Agency noted in its March 2018 monthly bulletin that “maintaining existing facilities operational is a growing challenge” for members of the Generation IV International Forum (GIF).1

The Nuclear Energy Agency was reporting on a February meeting of the Forum’s new task force, established to identify R&D facilities needed for the development of Generation IV systems. Presentations were made by the representatives of the six systems that GIF member countries are exploring ‒ gas-cooled fast reactors, sodium-cooled fast reactors, lead-cooled fast reactors, molten salt reactors, supercritical water-cooled reactors, and very high temperature reactors ‒ highlighting existing R&D capabilities and also gaps.

Filling those gaps will presumably be difficult if, as the Nuclear Energy Agency states, just maintaining existing facilities operational is a growing challenge.

Industry bodies such as the Nuclear Energy Agency are typically more bullish about Generation IV prospects. However the timelines are repeatedly deferred: Generation IV reactors were 20 years away 20 years ago, they are 20 years away now, and they will likely be 20 years away 20 years from now.

The Generation IV International Forum states: “It will take at least two or three decades before the deployment of commercial Gen IV systems. In the meantime, a number of prototypes will need to be built and operated. The Gen IV concepts currently under investigation are not all on the same timeline and some might not even reach the stage of commercial exploitation.”2

The International Atomic Energy Agency states: “Experts expect that the first Generation IV fast reactor demonstration plants and prototypes will be in operation by 2030 to 2040.”3 A 2015 report by the French government’s Institute for Radiological Protection and Nuclear Safety (IRSN) states: “There is still much R&D to be done to develop the Generation IV nuclear reactors, as well as for the fuel cycle and the associated waste management which depends on the system chosen.”4

The World Nuclear Association noted in 2009 that “progress is seen as slow, and several potential designs have been undergoing evaluation on paper for many years.”5

1. OECD Nuclear Energy Agency, ‘Generation IV research and development’, NEA Monthly News Bulletin – March 2018, www.oecd-nea.org/general/mnb/2018/march.html

2. www.gen-4.org/gif/jcms/c_41890/faq-2

3. Peter Rickwood and Peter Kaiser, 1 March 2013, ‘Fast Reactors Provide Sustainable Nuclear Power for “Thousands of Years”‘, www.iaea.org/newscenter/news/2013/fastreactors.html

4. Institute for Radiological Protection and Nuclear Safety, 2015, ‘Review of Generation IV Nuclear Energy Systems’, www.irsn.fr/EN/newsroom/News/Pages/20150427_Generation-IV-nuclear-energy-systems-safety-potential-overview.aspx

Direct download: www.irsn.fr/EN/newsroom/News/Documents/IRSN_Report-GenIV_04-2015.pdf

5. World Nuclear Association, 15 Dec 2009, ‘Fast moves? Not exactly…’, www.world-nuclear-news.org/NN_France_puts_into_future_nuclear_1512091.html

Nuclear waste information by David Noonan

Papers and submissions by David Noonan B.Sc., M.Env.St., Independent Environment Campaigner

PROPOSED NATIONAL NUCLEAR WASTE DUMP IN SOUTH AUSTRALIA

Safety and security questions on ANSTO nuclear waste shipments to a port in SA (Dec. 2018)

Nuclear fuel waste: Extended storage at Lucas Heights or target SA (Nov. 2017)

Proposed national nuclear waste dump in SA – safety and security issues (2-pages-David Noonan, Nov. 2018

Submission to federal government re proposed national nuclear waste dump in SA (David Noonan, Nov. 2018)

David Noonan – Jan 2017 Briefing Paper – Nuclear waste store threatens Flinders Ranges

2015-16 PROPOSAL TO ESTABLISH A NUCLEAR WASTE IMPORT BUSINESS IN SOUTH AUSTRALIA

Briefing papers written by David Noonan in 2016, responding to the Royal Commission’s final report:

Radioactive Waste and Australia’s Aboriginal People

Jim Green, 2017, ‘Radioactive Waste and Australia’s Aboriginal People’, Angelaki: Journal of the Theoretical Humanities, Volume 22, Issue 3, pp.33-50.

Click here to read as a PDF (and here is a link to the journal webpage).

Abstract: The treatment of Australia’s Aboriginal people by the nuclear industry (broadly defined as private- and public-sector agencies pursuing uranium and nuclear projects) is a poorly researched topic. That is not merely a gap in the academic research on related topics (the history of the nuclear industry in Australia; the history of race relations in Australia; etc.), but it has “real world” consequences. Put simply, the paucity of information about the mistreatment of Aboriginal people makes it easier for nuclear interests to repeat past practices; and conversely, proper documentation and publication of past (and current) practices detrimental to Aboriginal people can make it more difficult for nuclear interests to repeat those practices. Over the past decade Friends of the Earth Australia (FoE) has sought to partially remedy the information deficit in the context of its work with Aboriginal communities involved in debates regarding uranium mining and proposed radioactive waste repositories (the author works for FoE). One thread of that work is the growing body of multimedia work (and a Master’s thesis) by FoE member Jessie Boylan covering the legacy of the atomic bomb tests, uranium mining and waste repository proposals (see <www.jessieboylan.com>). Another thread of the project is detailed written documentation of past and present incidents of mistreatment of Aboriginal people by nuclear interests (as well as multimedia presentations of this material – see, for example, <www.australianmap.net>). This article builds on that research and focuses on attempts to impose radioactive waste repositories on the land of unwilling Aboriginal communities in South Australia.