After two days of meetings for the Fuel Cycle Subcommittee of the Blue Ribbon Commission on America’s Nuclear Future, the public had an opportunity to make statements before the commission. These public statements were meant to be less that five minutes and were allotted on a first come, first serve basis. So bright and early this morning, my friend Rod Adams and I were at the committee table signing up for our spot. I went first and delivered the following statement:
Commissioners, it is my pleasure to participate in this meeting and to address you today. Yesterday there were a number of discussions on the nuclear fuel cycle. These seemed to focus on whether or not fuel recycle should take place, and if it does, whether it should proceed in a thermal-spectrum reactor like our light-water reactors, or if it should proceed in a fast-spectrum reactor, of which the most commonly discussed type is based on solid fuel cooled by liquid sodium.
Another way to view these two options is that one represents the consumption of uranium-235, which is our only naturally-occurring fissile material, and the other represents the consumption of uranium-238 and its derivatives, primarily plutonium-239. Due to the specific properties of uranium-238, it can only be consumed in a sustainable manner in a fast-spectrum reactor.
There is another option that receives relatively little attention but has compelling attributes, and that is the use of natural thorium in nuclear reactors. Thorium is fertile and can be converted into a fissile nuclide, uranium-233, inside a reactor core. Uranium-233 has the compelling attribute of being able to produce enough neutrons in thermal-spectrum fission to continue the conversion of thorium to U-233 and then into energy.
Early in the nuclear age it was realized that this special property had superlative value. Early luminaries like Eugene Wigner and Alvin Weinberg worked to develop nuclear reactors based on liquid fuels. Research focused on a fluoride salt fuel form because it was the only appropriate liquid into which thorium could be dissolved as a true solution. Weinberg’s research and development program at Oak Ridge in the 1960s showed that it was possible to build and safely operate liquid-fluoride thorium reactors.
The fluoride fuel form is particularly compelling since it represents the most chemically stable form of nuclear fuel. In fact, all of our nuclear fuel goes through a fluoride form in today’s nuclear fuel cycle, preparatory to enrichment. We know how to turn uranium oxide into uranium fluoride and we do it every day at conversion plants. Then we successfully use uranium fluoride in enrichment plants. Many of these technological accomplishments are directly applicable to the use of thorium and uranium fluorides in fluid-fueled reactors.
Thorium’s performance means that it is possible to build a reactor that, once started on fissile material, requires no additional fissile input and runs only on thorium. This has profound consequences for our energy future.
Fluoride reactor technologies can also be used to help solve our current nuclear waste concerns. Our spent uranium-oxide could be fluorinated into a fluoride fuel form. Once converted, it is straightforward to remove the uranium that comprises roughly 95% of spent nuclear fuel into uranium hexafluoride gas that could be removed and potentially recycled.
The same nuclear technology that allows us to use thorium could also be used to destroy plutonium while extracting electrical energy. Fluoride fuels will not require the long and lengthy fuel qualification programs that solid fuel require. Fluoride fuels are impervious to radiation damage due to their ionic chemical bonds. They do not swell, crack, or undergo other property changes under strong irradiation. The base fluoride can be used and reused essentially forever, by adding fuel and removing fission products periodically.
I encourage the commission to strongly consider the potential benefits of using fluid-fueled reactor technology to solve our current nuclear waste concerns as well as to open a bright new energy future based on the effective use of natural thorium.
After I spoke, Rod Adams spoke about the importance of nuclear energy in realizing low-cost energy. Another gentlemen spoke about the importance of getting certified as a professional engineer.
By the time we had a chance to speak, the audience had dwindled considerably, from about 30 for the afternoon session to perhaps only 20 or so by the time we spoke. But a number of key people were in the audience, like Dr. Eric Loewen, the president of the American Nuclear Society. Of the original subcommittee members, only Per Peterson and Allison MacFarlane remained.
Previous to my statement I delivered a printed package of several “introductory” slides to the members of the commission.