Last August, I read an article that talked about hearing held in Washington, D.C. by Rep. Judy Biggert of Illinois on the subject of nuclear fuel reprocessing. Rep. Biggert would obviously have great interest in the subject, since Illinois has more nuclear power plants than any other state, and the spent fuel from these reactors has been piling up at each site.

She remarked in the hearings that today’s open-fuel cycle is “just plain wasteful.” I couldn’t agree more. She had recently traveled with Rep. Mike Honda of California and Rep. David Hobson of Ohio to inspect the La Hague reprocessing facility in France.

In the interest of presenting another option to these representatives, I took the occasion of these hearings to write a letter to each of them. I’m not sure if the letters were read, but in the hope that they might be useful, I am reprinting one of them here:

Dear Rep. Biggert,

I read with interest the recent hearings you held on the subject of the reprocessing of nuclear fuel as a mechanism for closing the nuclear fuel cycle. There is another option, that was actively pursued in the early days of nuclear energy but was not developed to its logical conclusion, that held tremendous promise for safe, economical nuclear power–the idea of the fluid-fuel reactor.

In the late 1940s, as luminaries like Enrico Fermi and Eugene Wigner debated the future of nuclear energy, one of the persistent arguments was over the form that the fuel should take. Many with a “mechanical” engineering background argued that a reactor was simply a machine to boil water, and for simplicity, should use solid-fuel elements. Others, specifically Wigner, with a “chemical” engineering background, argued that the reactor basically turns chemical elements from one form to another, and that all industrial chemical processes use fluid streams, and so should a reactor.

The two camps parted company, somewhat, with the solid-fueled breeder reactor work taking shape at Argonne National Lab and the fluid-fueled breeder reactor taking root at Oak Ridge National Lab. Well, to make a long story short, ORNL successfully built a number of fluid-fueled breeder reactor prototypes in the 50s and 60s. The most advanced was the Molten-Salt Reactor Experiment, which went critical in 1965 and ran for four years. The MSRE had superior safety capabilities, since it was the only reactor that could made completely safe from a loss-of-coolant accident….safe not only from accident, but from malice as well.

The idea of using a molten-salt reactor as a breeder revolved around using it to breed natural thorium to uranium-233, which is a very proliferation-resistant nuclear fuel (no operational nuclear weapon has ever been built from U-233, for very good reasons). The Argonne work in breeders focused on breeding U-238 to plutonium-239 in a fast reactor. As we know, Pu-239 is the favored form of fissile material for weapons.

The molten-salt reactor is extremely easy to reprocess, and the reprocessing can take place on-site, while the reactor is operating, by simply diverting a small stream of fuel and removing fission products and adding new fuel. Thus a molten-salt reactor does not need to shutdown for refueling and reprocessing. It is also an exceptionally good breeder for converting abundant natural thorium to power, but cannot do so for uranium-to-plutonium, which is why it was rejected in the late 1960s. The AEC wanted fast breeders to support the nation’s needs in weapons-grade fissile material, which the MSR could not do (it was a thermal reactor). But indeed, the reasons the MSR was rejected then would be its strongest selling points now.

Ma’am, you are unfortunately tasked with cleaning up the legacy of fifty years of short-sightedness of nuclear development, and from what I have read, you are trying hard to make good long-term decisions for the future. I would welcome any opportunity to explain further why future nuclear efforts based on molten-salt reactors can:

1. Provide us the safest reactor that has ever been built–and these safety features have already been demonstrated in actual operation.

2. Provide us with a reactor that has the high-temperature capabilities to generate electricity or hydrogen at > 50% efficiency. (current reactors produce electricity at ~35% efficiency and cannot generate hydrogen thermochemically).

3. Reduce the stream of nuclear waste by a factor of 100, and eliminate long-lived actinides from the waste stream, allowing us to build nuclear repositories that only need <1000yr isolation and have no proliferation risk. 4. Destroy long-lived nuclear waste from the nuclear reactors that have already been operating on the wasteful once-through cycle. Best Wishes, Kirk Sorensen