I have commented previously on the relative scarcity of uranium in terms of a viable fuel for nuclear fission, and which at current levels of usage worldwide will not last for more than about 50 years. I note that the Daily Telegraph yesterday published a letter extolling the virtues of fast breeder reactors, on the grounds that this way the uranium can be made to last far longer. This letter was supported by another one in today's Telegraph, but neither the author of this letter nor the editorial team have picked up on a notable error in the first case. However, there are often misunderstandings over such technical issues, in this case the estimate that 50 kilograms of uranium are sufficient to power a 1 GW fast breeder reactor for 40 years. As I explain below, the quantity is nearer 50 tonnes (not kilograms). The Telegraph have yet to print my letter on this matter, so I have copied it below, as it seems to me an issue rather central to the whole matter of nuclear power provision:
I think Paul Sutton (Letter, June 15) is being a little overoptimistic in his appraisal that just 50 kg of yellowcake would be sufficient to fuel a fast breeder reactor for 40 years. A closer estimate is 50 tonnes (not kilograms). Essentially, all the uranium (99.3% uranium-238) has to be converted ("bred") into plutonium in the fast breeder, rather than wasting it, and only using the 0.7% component, uranium-235 for fission as is usually done. 150 tonnes of yellowcake (mainly uranium oxide, U3O8) contains around 130 tonnes of uranium, which could (ignoring energy losses) fuel a fast breeder reactor for 130 years. Hence for a 40 year operational lifetime, 46 tonnes of yellowcake (call it 50 tonnes) would be required.
Despite the reassuringly good record of Dounreay over 20 years, there remain grave fears about the overall safety features of fast breeders: the liquid sodium coolant (used to avoid slowing down the fast neutrons needed to breed uranium-238 into plutonium-239) is a perceived potential fire hazard and the containment of plutonium, for fear of radioactive contamination and that it might get into the hands of terrorists, is a real public relations bugbear.
One alternative is to use thorium, which can be bred into uranium-233 as the nuclear fuel using slow neutrons, thus avoiding the liquid sodium coolant, and which has the following additional advantages. (1) Plutonium and uranium could still be consumed in such a reactor, but without the need to manufacture more plutonium. (2) While uranium-235 and plutonium-239 can be shielded to avoid detection "in a suitcase" to use that cliche, uranium-233 could not, because it is always contaminated with uranium-232, a strong gamma-ray emitter, which is far less easily concealed as a "bomb". These issues are discussed in detail at: ergobalance.blogspot.com, which your readers may find interesting.
My point is that there has been nothing explicit mentioned in the press as to whether the U.K.'s "new" reactors will be fast breeders or not. If not, the alternative fission reactors, implemented by around 2025, will have only 30 years worth of fuel left on the clock to run them. Is it worth the effort, given the enormous engineering effort and cost involved. Are they a stop-gap measure to keep the lights on in the country, while the potential of renewables is explored? I doubt it, since all discussion about our new generation of nuclear is presented as "the solution" to global warming by cutting CO2 emissions, with no reference to any time limit.
I am confused, and so is the general public, notwithstanding numerical faults in letters published in support of fast breeder reactors - an uncomfortable technology, in so many ways, albeit one potential means to make the uranium last for probably several hundred years, which might be a blessing or a curse depending on the show of hands into which it will ultimately find itself. In a poll conducted by The Sunday Telegraph, 47% of the sample were opposed to building new nuclear power stations, while 40% were in favour. Interestingly, 56% of men want nuclear, but only 26% of women share that view. It is encouraging that 79% of those surveyed had taken practical steps to reduce their own energy consumption, for example insulating the loft or fitting energy efficient light bulbs.
Politically, the nuclear issue remains a hot potato, with some Scottish Nationalist M.P.'s accusing Mr Blair of intending to dump radioactive waste in Scotland. Mr Blair insists that nuclear is essential to address the energy security needs of the country, stating that "we have to be prepared to take the decisions necessary to make sure that we don't end up in a situation where we are entirely dependent on foreign imports of gas."
Fair enough, but only 18% of our energy is provided in the form of electricity, which is the only form provided by nuclear in the U.K. so far, although other thermal processes, e.g. the sulphur - iodine cycle, to produce hydrogen are in principle possible. Only 20% of that 18% of total energy in the form of electricity is produced by nuclear. How does this get around the quantity of natural gas that is currently imported for electricity production, unless there is a second "new" generation of nuclear plants planned, to increase the share of nuclear in the electricity market? Additionally, much of the imported gas is burnt directly for space heating, and the new generation of nuclear plants will not substitute for this. We will surely still be dependent on imported gas for both electricity and direct heating, even with "new" nuclear. I remain confused.