MOX - But what for?

June 27, 2013

Japan unlikely to use MOX fuel in nuclear reactors

http://mainichi.jp/english/english/newsselect/news/20130627p2a00m0na014000c.html

The government is highly unlikely to go ahead with the use of uranium-plutonium mixed oxide, or MOX fuel, in nuclear reactors as it had planned, even though a freighter carrying nuclear fuel reprocessed in France has arrived back to Japan.

Japan possessed 44.3 tons of plutonium, including that stored in Britain and France, as of the end of 2011, according to the Cabinet Office's Atomic Energy Commission (AEC). If used for power generation, each reactor would spend only 0.4 tons of MOX fuel a year.

Therefore, Japan will likely fail to keep an international pledge it made not to possess plutonium that cannot be used because such fuel could be converted to nuclear arms.

Prior to the outbreak of the Fukushima nuclear crisis in 2011, the government had intended to introduce MOX fuel -- produced by extracting plutonium from spent nuclear fuel -- at 16 to 18 reactors by fiscal 2015. However, it is particularly difficult for the use of such fuel in 26 boiling-water reactors, the same type as those at the tsunami-hit Fukushima No. 1 plant, to meet new safety requirements.

Four utilities are expected to apply to the authorities for permission to reactivate 12 of their idled nuclear reactors beginning in July. All of them are pressurized water reactors.

MOX fuel could technically be used in only four of these reactors, according to government officials. The four reactors are the Nos. 3 and 4 reactors at Kansai Electric Power Co.'s Takahama power station, the No. 3 reactor at Shikoku Electric Power's Ikata plant and the No. 3 reactor at Kyushu Electric Power's Genkai plant.

Before the outbreak of the Fukushima nuclear crisis, utilities had gained consent from local communities for the use of MOX fuel in 10 reactors, including J-Power's Oma power plant that is under construction. Such fuel had actually been used at four of the reactors including the No. 3 reactor at the Fukushima No. 1 plant until the nuclear disaster.

But the Fukushima reactor was stopped following the disaster and the three others have been suspended for regular inspections. The three still cannot be reactivated in the aftermath of the nuclear crisis.

The use of MOX fuel is an important part of the government's nuclear fuel cycle project in which spent nuclear fuel is reprocessed and reused. While the use of such fuel allows efficient and effective use of plutonium, there are technical problems, such as a decline in the efficiency of control rods used in the operation of the reactors, according to experts.

The Monju prototype fast-breeder reactor, which produces electric power by causing the nuclear fission of plutonium and generates more plutonium than it consumes, had previously been the core of the nuclear fuel cycle project.

However, there is no prospect that the reactor, whose operation had been suspended following a sodium leak in 1995, will be resumed in the foreseeable future because it has come to light that since November last year workers failed to examine more than 10,000 parts of the reactor.