Outline of the safeguards implemented at the Rokkasho uranium enrichment plant

The Rokkasho uranium enrichment plant is Japan's first commercial scale enrichment facility. Construction began in October 1988, and normal operations were launched in March 1992 with an initial capacity of 150 t separative work units per annum. Facility Attachment negotiations with the IAEA concerning material accountancy and the scope of inspections at the Rokkasho plant began in October 1990. An agreement was reached in September 1991. Regulations on material accountancy were also approved by the Government in September of the same year. The main features of material accountancy in the Rokkasho plant are: (a) two material balance area (MBA) structures, consisting of a storage MBA and a process MBA; (b) in-operation physical inventory taking by simultaneous switch-over of feed, product and tails flows; (c) evaluation of material balance by the uranium element balance method, which does not hamper operations at the plant. The Rokkasho plant has adopted several safeguards relevant designs to enable efficient and effective limited frequency unannounced access inspections in the cascade area. (author). 3 figs, 2 tabs