Following Japan's recent announcement that it is correcting the amount of plutonium previously declared to the International Atomic Energy Agency (IAEA), the United Nations watchdog has acknowledged that the amount of nuclear material transferred to waste storage in that country had not been adequately measured in the past.
IAEA Director-General Mohamed ElBaradei stressed that the Agency "remains confident in its conclusion that no nuclear material has been diverted" from the Tokai Reprocessing Plant (TRP).
In a statement issued Tuesday, the IAEA said it has been working with Japanese authorities and the Plant's operators to introduce improved measurement techniques there. The corrected amounts are expected to be in line with the IAEA's own independent verification data and based on measurement methodologies endorsed by the Agency.
The Agency has been inspecting the facility since 1977 and in 1996, reached agreement with Japan on random sampling of the high active liquid waste (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 from 1997 to 2000 in which the TRP was shut down, studies were undertaken by the IAEA, State authorities and the Japan Nuclear Cycle Development Institute, 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.