The Mainichi Shimbun answers some common questions readers may have about reusing plutonium for power generation.
Question: I heard that there were problems with a type of nuclear fuel used in power plants in Japan. It was called “plu-” something…
Answer: You have to think about “pluthermal” electricity production. Plutonium extracted from irradiated nuclear fuel and then processed can be reused as nuclear fuel. Generating electricity from this recycled nuclear fuel is called pluthermal power generation. In this method, conventional nuclear fuel and recycled nuclear fuel in a ratio of 2 to 1 are placed in nuclear reactors.
Q: Isn’t that called “generating energy from recycled fuel”?
A: This recycled nuclear fuel is called “MOX (mixed oxide) fuel”, and it is a mixture of recycled plutonium and uranium. “Pluthermal” is a Japanese-English word referring to the method of generating electricity using “plutonium” in a conventional “thermal” nuclear reactor.
Q: Why produce electricity using the pluthermal method?
A: MOX fuel is planned to be used in next generation ‘fast breeder’ reactors, but there is no set completion date for the new design yet. As a result, the amount of plutonium for MOX fuel held by power companies across Japan has increased to some 46 metric tons. That’s enough for thousands of nuclear bombs, and Japan would be criticized by the international community if it kept the plutonium instead of using it to generate electricity. This is why electricity companies in Japan seek to produce electricity by the “pluthermal” method: to consume their stocks of plutonium.
Q: Is the plutonium exhausted?
A: No. There are only four reactors in Japan that can generate electricity by the “pluthermal” method and that the Nuclear Regulatory Authority has allowed to resume operations, with only one currently in operation. The power industry had planned to operate 16 to 18 such reactors, but following the 2011 meltdowns at Tokyo Electric Power Company Holdings Inc.’s Fukushima Daiichi nuclear power plant, the industry revised its objective of a minimum of 12 reactors capable of operating with MOX fuel. commissioning by FY2030. Even if they come on stream, however, experts have pointed out that these reactors cannot be expected to consume as much plutonium as fast breeder reactors.
(Japanese original by Suzuko Araki, Department of Science and Environmental News)