The Mystery of Japan’s Growing Stockpiles of Separated Plutonium -Nuke Info Tokyo No. 168

by Masafumi Takubo, Kakujoho Website Operator

At a regular meeting of the Atomic Energy Commission (AEC) of Japan on July 21, the AEC secretariat presented a report saying that Japan’s separated plutonium stockpile had increased by 0.7 tons to 47.8 tons as of the end of 2014, from 47.1 tons the year before (about 37 tons held in Britain and France and 10.8 tons in Japan). The report explains that the 0.7 ton increase was the amount separated during 2014 and added to the stockpile, and that, including this, approximately 20.7 tons of separated plutonium are stored in Britain, with the remainder of about one ton of plutonium scheduled to be separated and added to the stockpile by about 2018.

This means that Japan’s stockpile has, in fact, reached nearly 49 tons. This happens to be about the same as the amount of plutonium separated in the U.S. nuclear weapons program that the government has declared to be in excess of military needs. While the U.S. is struggling to find ways to dispose of its surplus plutonium, Japan’s plutonium stockpile continues to grow, although the Rokkasho reprocessing plant is still not operating, and despite completion of physical reprocessing of Japan’s spent fuel in Europe. This article examines the reasons for that increase.

When reporting on September 16 of last year that Japan’s plutonium stockpile as of the end of 2013 had increased by about 3 tons to about 47 tons from 44 tons at the end of 2012, the AEC secretariat explained the net increase of 2.3 tons as follows: “We have been told that because reprocessing has proceeded at Britain’s reprocessing plant, about 2.3 tons was added newly to the allocation … of plutonium scheduled to be returned to Japan, or to the stockpile, in 2013.” In response to the question “Would this mean that the reprocessing plant in England is still operating?” from acting chairperson Nobuyasu Abe, they said, “Yes, the U.K. reprocessing plant is still operating.” This sounds as if they were explaining that 2.3 tons of plutonium were actually separated in the reprocessing of Japan’s spent fuel in 2013. (The remaining 640 kilograms of the approximately three ton increase are in the mixed oxide (MOX) fuel of Genkai NPS Unit 3. AEC had made this amount disappear from the data just because it was loaded into the reactor in 2011, but it reappeared in the data when it was retrieved unused from the reactor in March 2013, so there was no actual increase.)

At that time, the acting chairman seems to have accepted the secretariat’s explanation, but in fact, we know from Britain’s records that reprocessing of spent fuel from Japan’s light water reactors at THORP (the Thermal Oxide Reprocessing Plant) was completed in September 2004 (reprocessing at the B205 facilities of the particular kind of spent fuel from the Tokai Daiichi NPS was completed in January 2006). According to the contract, the “allocation” of plutonium to the client is performed with no regard to the actual time of the physical reprocessing, and that is how an allocation of 2.3 tons to Japan came to be added in 2013.

In response to a query on this issue from the office of House of Representatives member Tomoko Abe, the secretariat admitted on November 13, 2014 that it had received an explanation from the Federation of Electric Power Companies that the 2.3 tons had not actually been reprocessed and separated from Japan’s spent fuel in 2013. They went on to state, “According to the nuclear power plant operators, as of 2013 there was about one ton of plutonium remaining to be allocated to Japan from spent fuel sent to Britain.” Regarding France, on December 1 the secretariat finally responded that they’d heard from the operators that no additional allocation was scheduled in the future. What the above story signifies is that not only has the total of 3.3 tons (2.3 tons plus 1 ton together) not been touched upon by the government’s plutonium supply and consumption plans revolving around the pros and cons of initiating operations at the Rokkasho Reprocessing Plant, but also that the AEC secretariat itself does not understand the situation.

Let’s take another look at this year’s explanation. “In the U.K, approximately 20.7 tons of separated plutonium is held including approximately 0.7 ton which was separated and added to the stock in 2014. Approximately 1 ton of plutonium from the remaining spent fuel consigned to the U.K. will be separated and added to the stockpile by 2018, when the reprocessing facility in the U.K. is scheduled to be closed” (original English statement). This sounds as if the amount actually reprocessed and separated from Japan’s spent fuel in 2014 was 0.7 tons; and that the amount, in addition to that, that still remains to be separated from Japan’s spent fuel is about one ton. It also means that as of the end of 2013, an allocation of a total of 1.7 tons remained. This is clearly inconsistent with last year’s reply from the secretariat, including their explanation of the actual timing of reprocessing.

In a statement on November 20, 2014 to a local group monitoring the British reprocessing plant, the Nuclear Decommissioning Authority (NDA) of the U.K. clarified that the reprocessing of Japan’s “standard” light water reactor fuel had been completed in 2004, but that there was a very small quantity of Japanese material – in the form of fuel that has undergone Post Irradiation Examination (PIE) at Sellafield and, because of its ‘difficult’ form, will now undergo ‘virtual reprocessing’ rather than being put through THORP. In NDA’s proposal for virtual reprocessing, rather than physical reprocessing, “a radiologically equivalent amount of waste” and “an equivalent amount of nuclear materials” “will be allocated and then returned to the customer as if the fuel has been reprocessed.” The U.K. government agreed to this procedure officially on October 16, 2014. According to data the British Department of Energy and Climate Change presented at a stakeholders meeting on January 9, 2015, there were 1.39 tons of unprocessed spent fuel belonging to Japan. The plutonium content should account for less than one percent of that amount, although the degree to which virtual reprocessing is related to the mystery described above is unclear.

Unfortunately, it cannot be said that there is a high level of concern among Japan’s citizens about the fact that Japan is planning to start operations at the Rokkasho Reprocessing Plant, which has a capacity to separate eight tons of plutonium a year—enough for 1,000 nuclear warheads under the calculation method used by the International Atomic Energy Agency (IAEA), without even providing a clear explanation of why its plutonium stockpile has been increasing.

Under an agreement with Russia in 2,000, the U.S. promised to dispose of 34 tons of surplus weapons grade plutonium. Intending to make MOX fuel from it for irradiation in light water reactors, it began building a MOX fuel production plant in Savannah River, South Carolina in 2007. The plant has been subject to construction delays and cost overruns, so on September 8, 14 former U.S. governmental energy and national security-related officials and specialists requested the Secretary of the U.S. Department of Energy to scrap the plan and introduce different disposal methods.* The letter emphasized that from a nonproliferation point of view such a policy would put the U.S. in a much better position to urge Japan to put off its startup plan for the Rokkasho Reprocessing Plant. The signatories included former U.S. Assistant Secretary of Defense Joseph Nye, who has also been a candidate for ambassador to Japan and has great influence on U.S. policy toward Japan. How will Japan’s government and anti-nuclear movement react to this?

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