In June 2008 a 100-page white paper on ‘managing radioactive waste’ devoted about 50 lines (a little over one page) to spent fuel. Yet spent fuel contains by far the greatest quantity of radioactivity that is created in the waste from nuclear power. Its disposal has not been achieved anywhere in the world, and its indefinite storage on each reactor site will increase our vulnerability to accidents and attack.
When fuel is removed from a nuclear reactor it is intensely radioactive and hot, so it is stored in cooling ponds. In 2006 a US committee reviewing the safety of spent fuel storage concluded that the cooling and shielding: “…could be compromised by a terrorist attack that partially or completely drains the spent fuel pool.”
Such an event would lead to the rapid heat-up of spent fuel in a densely-packed pool to temperatures at which the zirconium alloy cladding would catch fire and release many of the fuel’s fission products. The fire could spread to the older spent fuel, resulting in long-term contamination consequences worse than those from the Chemobyl accident. The two reactor designs being assessed for use in Britain have ‘containments’ designed to prevent the escape of radioactivity, but their spent fuel pools are located in the building outside the containment. Above ground level, with voids to the sides and below, any objects that breach the pool wall would allow some or all of the water to escape.
To boost the efficiency of new reactors, operators plan to increase the enrichment of uranium in the fuel so it can be left in the reactor for longer. This gets more output, but increases the dangers of radioactive releases as the fuel cladding gets thinner. The increased risk persists throughout the storage and disposal of the spent fuel. The “burn-up” rate, a measure of the amount of electricity extracted from a given amount of fuel, is expressed in thousand megawatt-days per tonne of uranium (MWd/tU). High burnup spent fuel is twice as radioactive and twice as hot as spent fuel from reactors such as Sizewell B (the green line in Figure 1). Despite this the nuclear industry claim that the deep geological repository planned for Britain’s legacy of radioactive waste “could readily accommodate the smaller volumes of easier-to-handle wastes from that new generation of nuclear plants.”
High burnup spent fuel needs much longer to cool, perhaps thirty years in ponds instead of five, before it can be stored dry. The deep underground repository ‘concept’ as intended for disposal of Britain’s legacy waste – all the radioactive waste accumulated from Britain’s existing nuclear industry – cannot accommodate spent fuel that has twice the thermal power. A build up of heat would affect the waste, its containers, the engineered barriers and the ‘host rock’ formations. Even if it was spread out to avoid overheating, the geology of the UK lacks the homogeneity for such a large facility. High burnup spent fuel will be left on-site indefinitely if encapsulation and disposal prove impossible.
Far from being ‘easier to handle’, no plans for the safe storage of high burnup spent fuel have been put forward and the industry wants the taxpayer to take the raw spent fuel off their hands as soon possible, at a price fixed in advance, so that they don’t have to build expensive encapsulation plants at each site.
New reactors would impose huge additional hazards on existing nuclear sites. The use of high burnup (60,000MWd/tU) fuel is in its infancy and there is no experience of its long-term management after discharge.
High burnup spent fuel is twice as hot and twice as radioactive as ‘legacy’ spent fuel
It emits ten times as many neutrons per second as ‘legacy’ spent fuel
Dense-packing of high burnup spent fuel in the pools increases the likelihood of a fuel fire and meltdown should the pool water be lost in an accident or terrorist attack.
The on-site accumulation of high burnup spent fuel will greatly increase the radiological hazard and vulnerability of existing nuclear sites.
High burnup spent fuel will require greater radiation shielding during encapsulation and deep underground emplacement, and no designs for its safe encapsulation and emplacement exist.
It cannot be accommodated in the same ‘deep geological repository’ as that intended for legacy spent fuel and high-level waste.
The peak of radioactivity from a new programme of reactors will occur at least seventy years later than legacy waste (see Figure 2).
Uncertainties about high burnup spent fuel mean any level of disposal charge fixed now would expose the future taxpayer to the risk of huge uncovered liabilities.
As high burnup spent fuel would be far more hazardous and we don’t even know what to do with it, its creation is ethically unacceptable.
Since 11 September 2001 we have learned to be suspicious of prospective pilots who want to learn to take-off and fly aeroplanes but show no interest in learning to land them. There is an appalling resemblance in an industry that wants to build and operate nuclear power stations but shows little interest in what it is going to happen with the lethal waste that results. The possibility that these dual threats could smash together should preclude the development of nuclear power. Indifference to the possibility is a dereliction of the primary duty of government to ensure the security of the nation.
Hugh Richards is a member of the Nuclear Consultation Working Group and has been involved in the environmental movement since 1972. He stood as a Green Party candidate in the 1992 general election. His detailed report, Too Hot to Handle, is available at: www.nuclearconsult.com
