By Ed Pheil
I mentioned at the Thorium Energy Conference 2013 that accelerator driven systems (ADS) were likely to hurt the nuclear industry more than help it with the following discussion.
The ADS proponents are justifying their participation, including with thorium, on the basis of two concepts that cater to the anti-nuclear crowd.
A) ADS supporters imply that nuclear reactors can blow up like a bomb. They imply this by saying we should not allow reactors to go critical. They think ADS systems are needed because they allow the reactor to stay subcritical, and inject the extra needed neutrons to create power. In actuality, commercial nuclear reactors have NEVER had a problem with criticality problems coming any where near a risk to the public. Also, to minimize the power of the accelerator needed you need to keep the reactor very close to critical, so it still needs control rods. That means you can STILL have the same criticality accident risk with rods, plus a steam line rupture equivalent accident that could take you critical. If the keff is too high and you turn on the accelerator at too high a neutron generation rate, you could also take the reactor super-prompt critical; being able to shut down the accelerator as claimed by the ADS community would not help you.
B) ADS advocates also say that transuranics (TRU’s), also known as minor actinides (MA) in Europe, ARE a major problem, again catering to the anti-nuclear community. All of the MA’s in the world would not fill the room we were in at the conference center, barring criticality control and cooling systems. That is, only the MA’s after reprocessing by removing the air, cladding, useful fuel, and fission products (FPs). Spent fuel with all those things un-reprocessed would only cover 1 football field to a depth of 7 meters. So, there is no possible way that either spent fuel and, especially MA’s/TRUs, are a real waste problem because the volume of waste is SO VERY TINY.
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