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T O P I C R E V I E W
Posted - 07/16/2007 : 17:19:00 It is true that nuclear power as it exists today is a non-starter, not as a safety issue, but because of the thousands of tons of radioactive wastes it produces each year. While it is true that the light-water, thermal fission reactors that we have today should be scraped and light water reactors not considered in future energy generating plans, there is perhaps another type of fission reactor that we should take another look at.
Back in the 70's we experimented with breeder reactors. The idea was that breeder reactors could be made to produce fuel, namely plutonium, as they were burning fuel. Unfortunately, plutonium is what we can use to make bombs, and only two breeders were ever built in the US. However, a variant of the breeder might prove to be a viable part of future energy planning in the US.
How could a potential weapons reactor be suitable for power generation? It turns out that "fast" liquid metal cooled reactors with a special kind of fuel reclamation have many advantages over slow, light water thermal reactors, not the least of which is that they can be made to produce 1/100th the radioactive wastes of current reactors. That is to say that a 1Gig-watt nuclear plant today will produce roughly 100 tons of radioactive waste per year, some of which might take 10,000 years to become only moderately radioactive, while an equivalent fast metal reactor will produce about 1 ton per year. 10,000 years is basically the time it took people to get from the stone age to our present day! Nothing that man can do can be guaranteed for such a span of time. Not only that, but fast liquid metal reactors can be made to consume 95% of their fuel, while our present reactors consume about 5% before they must be refueled--the rest is waste!
The most attractive aspect of fast liquid metal reactors is that they can be made to eat much of our current wastes. This means that the thousands of tons of spent fuel can actually be burnt by a new breed of reactor with 95% efficiency! And finally, the ultimate wastes of fast liquid metal reactors need only be stored for hundreds not thousands of years--these new reactors eat some of the really bad stuff like strontium 60 and cesium 137 leaving some transuranic elements and fission products that are not suitable for making bombs.
Along with these aspects of fast metal reactors is the fact that they produce no other environmental pollutants, C02, CH4 and alike. They are also low pressure reactors that make them inherently safer to run. Although the wastes from fast liquid metal reactors are relatively small and not suitable for weapons, they must still be stored for a couple of hundred years. This is the greatest drawback and the aspect of using even advanced fission reactors for significant power generation that must be carefully considered.