New Measurement Techniques Correct PU Inventory In Japanese Reprocessing Plant
PR 2003/02 (28 January 2003)
Vienna, 28 January 2003 – At its briefing to the Japan Atomic Energy Commission on 28 January 2003, the Japan Safeguards Office (JSGO) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT) announced that, due to the introduction of more precise sampling and analytical measurement techniques for measuring plutonium in the high active liquid waste (HALW) storage tanks at the Tokai Reprocessing Plant (TRP), the Japan Nuclear Cycle Development Institute (JNC) is correcting the amount of plutonium declared in past accountancy reports to the IAEA. The corrected amounts are expected to be in line with IAEA's own independent verification data and based on measurement methodologies endorsed by the IAEA.
The IAEA has recognized for some time that the amount of nuclear material transferred to waste storage had not been adequately measured in the past and has worked with the facility operators and State authorities to introduce improved measurement techniques. IAEA Director General, Dr. Mohamed ElBaradei stressed however, that "the Agency remains confident in its conclusion that no nuclear material has been diverted from the facility". This conclusion is based on a range of activities under the NPT Safeguards Agreement between the Agency and Japan, as well as under the Additional Protocol to that Agreement which gives the Agency broad access to nuclear fuel-cycle related information and locations.
TRP, in Tokai-mura, Ibaraki prefecture in Japan, was built in the early 1970s, using 1960s -era design and technology. The IAEA began inspecting the facility in 1977. In its annual evaluation of safeguards implementation, as reported to the IAEA's Board of Governors in the Safeguards Implementation Report, the Secretariat has regularly noted the need for strengthening safeguards implementation at TRP, particularly with respect to procedures used for the measurement of nuclear material in the waste produced.
In 1996, Japan and the IAEA reached agreement on IAEA sampling, on a random basis, of the HALW transferred in the past to the storage tanks. The results of the sampling activities, which were conveyed to the Japanese authorities in 1998, indicated differences between IAEA measurements of the material and the operator declarations. During the period in which TRP was shut down (1997-2000), studies were undertaken by the IAEA, State authorities and JNC, resulting in further improvements in the techniques used by the operator for sample preparation and analysis to more accurately measure the plutonium content of the material transferred to the HALW storage tanks. JNC began implementing these improved techniques in March 2002. The corrected accountancy reports on the inventory of the HALW are expected to be in line with IAEA verification data. In November 2002, a group of IAEA experts have performed a six-week review of historical data including a detailed analysis of operator declarations since 1977 to further increase the Agency's confidence in its conclusion that no nuclear material has been diverted from the facility.
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