Why I am not worried about Japan’s nuclear reactors.

morgsatlarge.wordpress.com ^ | 12 March, 2011 | Dr Josef Oehmen

[Errant]

Thanks for posting what you've found. That's the kind of information the general public should be receiving so that they can better understand. The best antidote for fear and ignorance is knowledge.

[theBuckwheat]

You are exactly right. But this is really more a story about bureaucratic and institutional momentum, risk-aversion and operating experience than it is about technology.

The first reactors were built to create U-235 and plutonium for nuclear weapons as part of the arms race against the Soviets and later the Red Chinese threats. When the Navy started to look for ways to power submarines with nuclear reactors, this was the design that we had the most operating experience with. After the Navy started running these power plants in subs, technicians who were experienced at running them came into the civilian work force. Thus, this design had the least risk for public utilities to use and the regulatory bureaucracy was also staffed with such people. So, this design was comfortable to everyone and other designs had a far higher burden of proof of safety and reliability.

The problem is that the BWR fueled with uranium must have active safety. Even when scrammed, it must have active cooling. In this horrible catastrophe in Japan, we are seeing beyond the worst-case. Not only a failure of the backup of one reactor, but of all three. The hydrogen explosions are the result of core temperatures so high that water is getting disassociated. This is pretty bad.

And as I showed, there are reactor designs that cannot fall into this failure mode. We have even had one of them running, a thorium design that was shut down for weekends by turning off the cooling system and allowing the overtemp plug to melt! (Thus proving its fail-safe mode operation every weekend)

Yet, I just read last week of a new fail-safe reactor design from a US company that is **looking for another country to allow a test reactor to be built** because the US regulatory bureaucracy is unable to process applications for new reactor designs!!