Nuclear fusion has been a long-held ambition of the nuclear industry and governments who support nuclear power for decades. Since the end of the Second World War, governments around the world, backed by elements of their scientific communities, have always lauded fusion power as the ‘next step’ above and beyond fission that is almost within reach, yet many billions has so far been spent over the past seven decades on what has often been called by its critics an ‘energy pipedream’.
Nuclear Free Local Authorities (NFLA) has rarely commented on nuclear fusion, given such energy projects have yet to be commercially realised. All have foundered around the complex challenges in developing such technology, many of which in the third decade of the 21st century remain unsolved.
In summary, to date, none of the experimental reactors in operation have produced more energy than was put into them.
However, given the current UK Government’s declared intent to invest further money in fusion reactor development with the aspiration to develop a commercially viable design within two decades, it would be remiss of NFLA not to comment on this consultation.
Operating a fusion reactor presents many challenges and risks.
In response to concerns expressed by member authorities, the NFLA itself commissioned a special briefing on this subject (Edition 62, published in September 2020) ‘NFLA New Nuclear Monitor Policy Briefing – NFLA Response to the UKAEA call for potential sites to host a nuclear fusion reactor in England’.
The Committee on Radioactive Waste Management (CoRWM) has also recently published a preliminary position paper ‘Radioactive Wastes from Fusion Energy’ (6 December).
Many of the following comments are taken from the NFLA paper, particularly from pages 4-6, but reference is also made to specific sections of the CoRWM report.
As Earth lacks the intense pressure generated by the Sun’s gravity, and so cannot replicate the conditions favourable to fusion found there, there would be the requirement to super-heat the interior of the reactor to 100 million degrees centigrade, or six times the Sun’s temperature, to generate the reaction. Such a temperature and the subsequent reaction would have to be safely contained with the reactor vessel.
In addition, a fusion reactor has high operating costs as the system itself ‘gobbles up’ much of the energy that it generates to run its coolant, containment, pumping and other engineering systems. Any failure of these systems at any time would compromise the safe operation of the reactor.
The reaction generated through the employment of neutron-rich isotopes of deuterium and tritium would produce harmful by-products such as:
Progressive radiation damage to structures impacting on their long-term integrity. The neutron radiation produced knocks atoms in the surrounding structure out of alignment creating swelling, embrittlement and fatigue, and prolonged exposure would put the very integrity of the reactor vessel in peril. CoRWM said: ‘The primary components of the fusion reactor system are likely to require disposal, including the activated front wall, blanket, divertor and vacuum vessel materials.’
The generation of radioactive waste. Fusion will generate huge masses of highly radioactive material that must eventually be safely disposed of. Many non-structural components inside the reaction vessel (and, in liquid-metal cooled fission reactors, the lithium blanket) will become highly radioactive by neutron activation. In addition, molten lithium represents a fire and explosion hazard. While the radioactivity level per kilogram of waste would be much smaller than for fission-reactor wastes, the volume and mass of wastes would be many times larger. CoRWM also challenged the presumption in the consultation paper that fusion does not generate significant nuclear waste: ‘Nuclear fusion technology is advocated as not being compromised by the burden of generating long lived nuclear wastes. It is evident that this claim is challenged by the expected generation of some significant volumes of LLW and likely ILW arisings.’
The ever-present threat of the release of radioactive tritium. Tritium will be dispersed on the surfaces of the reaction vessel, particle injectors, pumping ducts, and other appendages. 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. The release of even tiny amounts of radioactive tritium into groundwater would significantly compromise public health.
The possible production of weapons-grade plutonium 239, adding to the threat of nuclear weapons proliferation. The open or clandestine production of plutonium 239 is possible in a fusion reactor simply by placing natural or depleted uranium oxide at any location where neutrons of any energy are flying about. Fusion reactors will also have an inventory of many kilograms of tritium, providing potential opportunities for diversion for use in nuclear weapons. Just as for fission reactors, IAEA safeguards would be needed to prevent plutonium production or tritium diversion.
In addition, as plant workers would be otherwise exposed to significant doses of radiation the plant would require heavy biological shielding even when it is not operating.
In our response specifically to Consultation Questions 5 and 7 in the consultation, the NFLA is gravely concerned that the government appears intent upon ‘watering down’ the regulatory regime applicable to fusion and demands that fusion power plants should be considered to be nuclear installations under the terms of the Nuclear Installations Act 1965, and so subject to the same licensing and regulatory regime overseen by the Office of Nuclear Regulation that applies to fission reactors.
The paper concedes that ‘with the uncertainties involved in fusion power plants, it is possible that the regulatory approach based on NIA 1965 could become more appropriate as the regulatory basis of fusion power plants if fusion design choices in the future involve a considerably higher degree of radiological hazard’ (p46).
Given the challenges and risks associated with operating fusion reactors, the NFLA has no doubt that the same regulatory approach to fusion should apply from the onset as it does to fission, and that this should extend to operations and the treatment and transport of arisings.
There is no logical reason to exclude fusion on safety grounds, and the NFLA can therefore only conclude that the government’s motive is to reduce the administrative and cost burdens placed upon commercial operators entering the market.
The NFLA believes that consideration for the safety of plant operators and the public should come far above plant operators’ profits.
In addition, the paper makes several proposals which are of concern to the NFLA:
+ A lesser regulatory regime has the potential to compromise security, as well as safety, at fusion plants. We have already highlighted the proliferation risks and believe that sites should be subject to greater levels of security and IAEA safeguards.
+ The waiver of licensing and the proposed cap on liability appears only to give ‘carte blanche’ and reduce costs to operators and runs contrary to the usual policy of making the polluter pay.
+ Companies involved in nuclear transportation will have no liability as the government claims this will be a ‘disincentive to supply’.
+ It is unclear how the long-term responsibility and costs of decommissioning will be apportioned between plant operators and the UK Government. CoRWM also shares these concerns: ‘It may be noted that the recent call for expressions of interest to accommodate siting the STEP facility makes no mention of management of the arising radioactive waste. Future dialogue with local communities needs to ensure it is as open and transparent as possible on such matters.’
+ The Government seems intent upon permitting operators to dispose of waste in shallow disposal sites. Though this may be an attractive and less-costly option for commercial operators, the NFLA remains unconvinced that this will represent a disposal method that is safe and secure for the long- term.
This view was again supported by CoRWM in its recent report:
‘From a radiological perspective, it is reasonable to consider that, conceptually, wastes from a nuclear fusion power programme should be compatible with geological disposal, however, they may prove challenging for disposal in a near surface facility, given the long half-life and potential mobility of 14C and 94Nb.’
‘…some key activation products of concern, such as 14C and 94Nb, which are long lived, should be limited in near surface disposal facilities, given the reliance on engineered barriers to assure containment. 14C poses a particular challenge given its potential mobility in the near subsurface.”
My NFLA colleagues and I look forward to reading the outcome of the consultation in the hope that our suggestions will be accepted.
The above is the text of a letter sent by email by Councillor David Blackburn, Chair of the Nuclear Free Local Authorities Steering Committee, to the Department if Business, Energy and Industrial Strategy (BEIS) Fusion Team on December 15, 2021, in response to the BEIS public consultation.