The MOX fuel conundrum

MOX

nuclear fuel, which is a mixture of uranium and plutonium, arrived at the wharf of Kansai Electric Power Co.’s Takahama nuclear power plant in Fukui Prefecture on June 27.

Kepco plans to use MOX fuel in the Nos. 3 and 4 reactors of the Takahama plant, and Shikoku Electric Power will use it in the No. 3 reactor of its Ikata plant. The No. 3 reactor at Kyushu Electric Power Co.’s Genkai plant also has the capability to use MOX fuel.

These reactors are among the 12 pressurized light-water reactors, at five nuclear power plants, whose safety assessment under the Nuclear Regulation Authority’s new safety regulations was requested by four power companies in early July.

The attempt by power companies to restart nuclear power plants and use MOX fuel at some plants only deepens the contradiction that Japan’s power industry cannot escape. Use of MOX fuel is closely related to Japan’s nuclear fuel-cycle program, which is almost bankrupt. Yet, the government and the power industry stick to the program. They should change their thinking.

Under the nuclear fuel-cycle program, plutonium is extracted by reprocessing uranium fuel burned in nuclear power plants. The extracted plutonium is to be used as fuel for fast-breeder reactors. But there is no prospect that the prototype fast-breeder reactor Monju, which is out of operation, will become operative.

A mainstay reprocessing plant in Rokkasho, Aomori Prefecture, was to be completed in 1997. But its completion has been postponed due to a series of accidents.

To avoid the accumulation of plutonium, a core ingredient of nuclear weapons, Japan is commissioning most of the reprocessing of spent nuclear fuel to plants in Britain and France. The MOX fuel that arrived at the Tokahama nuclear power plant was manufactured in France. MOX fuel uses plutonium extracted from spent nuclear fuel and uranium.

As of the end of 2011, Japan had accumulated some 44 tons of plutonium in Britain, France and Japan. To reduce the amount of such plutonium, Japan’s power industry in 2009 drew up a plan to start using MOX fuel at 16 to 18 reactors by fiscal 2015

But so far MOX fuel has been used at only four plants. It is estimated that if MOX fuel is used for one year in a reactor, it will only burn 0.3 to 0.4 ton of plutonium. This will not contribute much to reducing Japan’s plutonium stockpiles.

It has also been pointed out that the effectiveness of control rods decreases when applied to MOX fuel and that MOX fuel is expensive. It is reported that in the case of MOX fuel for the Genkai plant, its cost is 4 to 6.5 times higher than uranium fuel.

The easiest way to reduce the accumulating plutonium should be to give up reprocessing spent nuclear fuel and the nuclear fuel- cycle project. As the Rokkasho reprocessing plant has been accepting spent nuclear fuel from the nation’s nuclear power plants, its storage capacity of 3,000 tons has almost been reached.

If the government and the power industry stop the nuclear fuel- cycle program, the Rokkasho plant will send spent nuclear fuel back to the nuclear power plants as industrial waste.

On average, on-site pools for spent nuclear fuel are reported to be already 70 percent full. To avoid having the Rokkasho plant send back spent nuclear fuel, the government and the power industry seek to continue the virtually bankrupt nuclear fuel-cycle project.

To get out of this conundrum, the rational solution should be to write a concrete timeline to end nuclear power generation.