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


With all things wizardly being topical, what better time to examine one of the practical skills that every self-respecting wizard should master: alchemy? But this near-magical ability to turn base metals into gold is not confined to fiction.

The quest for the philosopher's stone that has the power to transmute one substance into another has been the obsession of many great thinkers throughout history. The wealth and power that would come to anyone who mastered alchemy seduced many great scientists and philosophers, including Isaac Newton, Robert Boyle and John Locke. All tried to change one element into another, and all failed.

Then in 1919, the secret of alchemy was finally revealed in the physics department at Manchester University. The world's first successful alchemist was the New Zealand scientist and Nobel prize winner Ernest Rutherford, and his discovery was almost accidental. It began when one of his students noticed that when radioactive materials such as radium were placed in a sealed box of air, small amounts of hydrogen, which doesn't exist in ordinary air, began to mysteriously appear. Rutherford realised that in the presence of the powerful radioactive rays, nitrogen, which makes up more than three-quarters of the air we breathe, turns into two other gases -- hydrogen and oxygen.

The alpha particles being produced by the radium were embedding themselves within the nuclei of nitrogen atoms while knocking out single protons. What remained was an oxygen nucleus, while the protons themselves were actually nuclei of hydrogen. All that is needed then is for these nuclei to accumulate the requisite number of electrons and they become atoms of the respective gases.

Today, changing one element into another through such nuclear reactions is routine. What is exciting, and yet not widely known, is that such subatomic alchemy might end up playing a vital part in the way we produce clean energy in the future.

A loose interpretation of the second law of thermodynamics is that "there is no such thing as a free lunch."

And so it is with electrical energy production. If you burn fossil fuels, you generate carbon dioxide; if you build dams, you destroy the ecology of entire valleys.

Nuclear power is no exception. If you carry out controlled fission in a nuclear power station, you get long-lived radioactive waste, and that poses a long-term hazard to the environment unless it is dealt with properly. This has justifiably caused concern among many who would otherwise welcome nuclear power as a source of clean, carbon-free energy.

The favored option is to store the treated and vitrified waste in deep geological repositories. Understandably, people don't want this in their backyard, because material such as plutonium remains radioactive for tens of thousands of years. In the throes of deciding future energy policy, such concerns are a serious issue.

I find this a very strange concern; here we are trying to figure out how to avert the disaster of climate change, and yet the long-term problem of nuclear waste still worries us. Human civilization started less than 10,000 years ago, so to worry whether we'll be technologically advanced enough to deal with this buried waste thousands of years in the future, assuming we survive climate change, is utterly irrational. And, what if there was a way to incinerate the nuclear waste, destroying nearly all that plutonium and dramatically reducing the need for long-term storage?

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