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