JOIN USWhile India and China are keen on investing in nuclear energy, other countries are shying away thanks to the high risks involved. Nuclear safety is a major concern and so is the matter of safe disposal of highly toxic radioactive waste, writes C Sivaram.
There has been a resurgence of interest recently in setting up more nuclear reactors, especially by developing countries like China and India, despite countries like Japan and Germany deciding not to build any more reactors after the Fukushima incident which continues to spew out hundreds of tonnes of toxic radioactive water even now, resulting in the closure of all but two of the 50-odd Japanese reactors. South Korea too, which gets about 30 per cent of its power from nuclear energy, has had doubts about more than 20 of its 30 reactors coming under dubious maintenance. Also, after the Three Mile Island incident when an overheated uranium fuel caused a reactor meltdown, the US has built only one reactor in about three decades. The Chernobyl disaster was another grim reminder of what could happen if a reactor goes out of control.
The rising costs of fossil fuels and the global warming associated with the release of a teratonne of carbon dioxide over the two decades has led China and India to rethink their plan to meet future energy requirements. And this means considering increasing the share of nuclear power. Countries like India and China still get 70 per cent of their power from burning fossil fuels, especially coal. China sometime back was building a gigawatt power coal-fired plant every week with an annual coal consumption of about three billion tonnes, about 40 per cent of world total.
Annually, 40 billion tonnes of carbon dioxide is pumped into the atmosphere, which, in a few decades, would increase the greenhouse gas concentration by 30 per cent. So naturally nuclear power seems like the best alternative.
While the great advantage of nuclear power is that it does not add toxic chemical compounds and greenhouse gases to the atmosphere, it is imperative to stop and consider the disadvantages of generating nuclear power.
There are now around 450 nuclear reactors operating in some 30 countries totally generating less than 20 per cent of the total power consumed in the world. About 300 tonnes of uranium is required to power a gigawatt reactor over 10 years. Uranium is not easy to mine; nearlyone lakh tonnes are annually produced in more than 60 mines in 20 countries. After the uranium is extracted from the ore by acid or alkali solvents (extracting is a messy business!), the remaining liquid contains long-lived radioisotopes like radium that decays into carcinogenic radon gas. The toxic sludge residue, known as tailings, remains radioactive for thousands of years.
Disposal of this radioactive waste is a major concern. Kyrgyzstan — that produces a major chunk of uranium in the world —, Canada, Germany and the US have been facing major problems over the past decade in shifting and cleaning up millions of tonnes of uranium tailings that pose health hazards to inhabitants in their neighbourhood. The newer uranium mines are supposedly safer as far as environmental impact is concerned. Again, as the nuclear power industry has been running for 60-odd years now, the major problem has been handling the accumulated radioactive waste. For instance, the quantity of spent fuel accumulated by the US nuclear industry is more than 60,000 tonnes which is expected to double in the next three decades.
This is already exceeding the capacity of the cooling pools used to hold such materials. Annually, a single gigawatt reactor would produce 20 tonnes of such waste. One method adopted is to store such spent fuel in huge casks each costing a few crore rupees and storing only 10 tonnes! Again, extraction and processing of the waste has been found to cost much more than the new fuel is worth. Till recently Russia, France and the US earned money by reprocessing spent fuel of nations like Germany and Japan (the separated plutonium chemically combined to get the oxide is mixed with uranium to have a mixed oxide (MOX) fuel). However, the addition of highly radioactive fission products makes this plutonium difficult to use.
Also, the high processing fee of several crores per tonne and the stipulation that the plutonium and highly radioactive waste should be shipped back to the country of origin has convinced many countries to adopt the cask route. The US reprocessing plant, for example, in South Carolina is now occupied with cleaning up the resulting mess at an expected cost of about 10 lakh crore rupees!
Burning of tens of thousands of waste graphite from UK’s power stations as suggested would generate about a quadrillion-becquerels of radioactive carbon-14 in the atmosphere. Similarly, for the US, dumping of nuclear wastes in repositories like Yucca Mountains comes with attendant problems. Apart from the large capital needed at the start of a reactor’s life, a major problem is decommissioning of old reactors which again involve huge costs without generating any revenue.
In India, the Fast Breeder reactor is still in the test stage. Advanced designs like the pebble-bed reactor, where a large surface area is built with hundreds of layers of fuel, and the use of liquid metal or inert gas coolants are yet to be implemented on a full scale to study their performance over long periods.
If we have to generate 400 gigawatts over the next three decades, we have to build a gigawatt reactor every month! We just built around 20 reactors over the past 50 years! That apart, the use of thorium has its own problems, especially in the metallurgy aspect. Handling of vast quantities of toxic nuclear waste would be a very expensive and messy affair.
There are many issues involving nuclear safety that need to be addressed. The hope is on nuclear fusion power which may become a reality around 2030 but that too would lead to radioactive waste disposal problems. Nuclear fusion uses “clean” fuel like the hydrogen isotopes deuterium and tritium but this reaction, at a hundred-million degrees, generates mainly neutrons of high energy which would have to be moderated and this would, in turn, release radioactive waste that is likely to be even worse than fission reactors currently in vogue! Safety is a crucial aspect of nuclear power generation that needs to be considered. And there is still a long way to go to ensure safe and low cost of nuclear power in the long run.