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Chinese Eye Fast Breeders

And they'll likely regret it

2 min read

The Wall Street Journal reports that China plans to design and build an 800 MW fast breeder reactor to come online around 2020. The rationale is essentially the same as usual: concern that the country will not have enough uranium to fuel its growing reactor fleet, and a desire to stretch fuel by transmuting spent uranium  into new plutonium.  The trouble is, every country that has tried to do this by building breeders has failed: France, which runs what is by most accounts the world's most sophisticated nuclear industry, built a commercial-scale fast breeder only to close it down after a few troubled years. Japan's smaller-scale demonstration reactor suffered coolant leaks. A large Soviet breeder is believed to have caught fire.

The essential problems with breeders are easily stated. The fuel consists essentially of bomb-grade plutonium, which is highly reactive and very volatile. Cooling the reactor and transferring its heat to turbines requires use of liquid sodium, which is flammable and therefore must be even more rigorously contained than the water coolant used in conventional reactors.

In the very worst case, if there were a loss of liquid sodium coolant and the breeder's core started to melt, the reactor fuel could reconfigure itself into a critical mass and suffer what's called in expert jargon a "prompt critical burst"--that is to say, in plain English, a nuclear explosion.

I wish I could say to the Chinese, "Good luck," but actually I just hope they'll come to their senses and change their minds. One of the first things Jimmy Carter--a nuclear engineer--did after taking office was cancel the U.S. breeder program. He was right.

Earlier this year, a subsidiary of the Russian company Rosatom completed construction of a small 25 MW Experimental Fast Reactor in Beijing, fellow EnergyWise contributor Peter Fairley reported. It was to be loaded with fuel this summer, to test and demonstrate the basic technology of neutron capture. In a fast breeder reactor, fast neutrons emitted by fissioning plutonium are captured by non-fissile uranium-238, typically in a "blanket" surrounding the plutonium core. The U-238 transmutes to plutonium-239, which can be recovered and recycled as fresh fuel. Hence the claim that breeders produce more fuel than they consume.

Besides being hard to control, which affects design economics and public confidence, breeders suffer from the disadvantage that their fuel cycle depends on transportation of weapons-grade plutonium, an enticing target for terrorists. This was the main publicly stated consideration in Carter's decision to ditch the U.S. breeder program in April 1976 

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