Mon, Jul 30, 2007 - Page 9 News List

Nuclear waste: a necessary risk

Atomic power is crucial in the fight against global warming. When we need to deal with the leftovers, we'll have the technology

BY JIM AL-KHALILI  /  THE GUARDIAN , LONDON

One such strategy is known as accelerator-driven transmutation. The basic idea is to place the radioactive material in a machine and smash it up into much more stable products, with shorter half-lives using a beam of high-energy subatomic particles. The waste would still need to be stored, but would be much less hazardous. At the same time, the process of transmutation would eliminate other biologically toxic products that exist in "normal" nuclear waste.

The real beauty of the process is that it could generate more energy than is pumped in. The heat generated by splitting the waste nuclei can be used to generate electricity, part of which is used to run the accelerator and the rest fed into the national grid. The failsafe mechanism is that when the beam is turned off, the reaction stops. This type of plant is known as an "energy amplifier" and the idea has been around since the 1990s.

So how feasible is this ability to transmute our nuclear waste? More importantly, why is no one talking about it? After all, the nuclear waste problem is seen as one major obstacle stopping many people from embracing nuclear power as one of the key ingredients in carbon-free energy generation.

It is a source of deep concern that so many people still believe we can slash our reliance on coal and gas solely through renewable sources, such as wind and solar, along with energy conservation in buildings. These are vital, but if we are going to avert the disasters of climate change while enjoying the standard of living that most in the west would be unwilling to give up, we are going to have to continue our reliance on nuclear energy. If transmutation could be made to work, it would go a long way towards helping the world come to terms with it. Beyond this timescale, we are now finally and genuinely optimistic that the ultimate energy source will come online: nuclear fusion. But that's another story.

France has a well-funded program of research looking into transmutation. There are also initiatives in the US, Russia, Switzerland, Italy and Japan, which the UK government continues to "monitor." The reason no one has perfected the technology yet is that while in theory it should work, we still do not know exactly what the final transmutation products will be, and in what proportions.

The scientific community has to understand the science involved and the technology needed, its practicalities and potential impacts.

This takes years. The US and Europe have produced roadmaps of timescales of 20 to 35 years. Unfortunately, the nuclear industry does not see transmutation as viable and the onus is therefore on us to urge governments to act.

Many experts argue that while transmutation is a feasible future technology, there are several other options available too. The most widely touted is to use what is a called a fast-breeder reactor that would re-use the nuclear fuel over and over again until all the plutonium is burned up. Another option many nations are looking into is to use thorium as the basic nuclear fuel. It is more abundant in nature than uranium, and much less radioactive material is produced compared with uranium fuel cycles.

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