Nuclear energy is no panacea to world problems

According to an exhaustive study based on data from the nuclear industries, there are insufficient reserves of high grade uranium ore to deliver more than a small fraction of the world's energy needs based on present day, once through, no reprocessing, light water reactors. These are the conclusions of the studies conducted by Jan Willem Storm van Leeuwen and the late Philip Smith, emeritus Professor at the University of Groningen, as presented to a just held seminar at the Institute of Physics in London. What the Storm-Smith studies have done is to take a detailed look at the relative amounts of energy required to extract uranium from its ores, build plants, run them for 24 years at full power, which Jan Storm says, nobody has ever managed to do, decommission them and then look after the waste. At present, the only technology that looks economically attractive and is known to work without too many problems is to take uranium, enrich its U235 content slightly, burn it, and then take out the spent rods and store them. While fast breeders, which produce more fuel in the form of plutonium than they consume have successfully bred, the engineering problems associated with the liquid sodium heat extraction and the fuel containment cladding have never been fully solved despite decades of research and the expenditure of vast sums of money in seven countries. Reprocessing spent fuel is undertaken by BNFL but it adds to cycle cost, and nobody is at all keen on greatly expanding the amount put through such processes because of security worries and constant technical problems. The present world nuclear generating capacity is about 350 GW. This supplies about 16 per cent of the world's electricity requirement, which in turn meets about 16 per cent of the world's energy consumption, which is around 120 million GWh/year. If nothing is done, the nuclear contribution will fall to zero by about 2050. MIT, Storm said, estimates that it would be possible to install 1500 GW of nuclear electric generating capacity world-wide by the year 2050. This would require the consumption of 15 million tonnes of uranium using current technology. Unfortunately, known reserves of uranium ore are only about 4.5 million tonnes, much of it low grade. While nuclear power stations produce a very healthy energy surplus over their whole cycle when ore grades are 1 per cent uranium or more, this starts to fall off at 0.1 per cent and falls to nothing at 0.02 per cent. Below that, more energy is consumed to mine and process the ore than the power station produces. There is a lot of uranium in the world. Granite contains 4g of uranium per tonne, and since sea water contains 3.34mg of uranium per cubic metre and there are 1.37 billion cubic kilometres of it, the sea contains 4.5 billion tonne of uranium. Unfortunately despite best UK and Japanese attempts based on ion exchange technologies, nobody has ever come up with a remotely viable method of recovering it. The present situation in the UK is that 20 per cent of electricity comes from nuclear power stations and if nothing is done, only Sizewell B will still be working in 2020. In the world as a whole, we learned that there are 164 nuclear reactors on order, the largest proportion of which are to be built in China. However, Storm was of the opinion that the high grade Uranium ores will all be depleted in a decade, after which the world will have to turn to the lower grade Australian ores, which will be likely to have to be extracted using electricity generated by burning large quantities of low grade coal. The energy balance for wind turbines is such that they generate electricity equivalent to that used to construct them in about six months out of their eventual ten year life expectancy. Energy payback for photovoltaics is 4.4 years in the Netherlands and the UK, 2.2 years in Spain, and 1 year or less in the Sahara or Saudi Arabian deserts. Life expectancy is at least 20 years and as we have observed before, the entire world's energy demands could be met by photovoltaics covering a 600 km square area of desert. More information from www.stormsmith.nl