Safety assessment of TRU waste proposal

Recycle and MOX fuel fabrication plant generate radioactive wastes with transuranic (TRU) nuclide. The concentration of α nuclide is larger than the reference value (about 1 GBq/t), so that TRU waste fit for laying underground. For estimation, radioactive waste is reduced the volume and stabilized. We studied 18,000 m3 wastes with more than the reference dose (about 1 GBq/t) of α nuclide and waste with high concentration of I-129. The method is geological disposal. The waste is classified four groups by kinds of nuclide, concentration, chemical substances and solidification method. Engineered barrier, disposal system, underground facility, various kinds of environmental conditions and important events considered in nuclide migration analyses, conceptual models of nuclide migration analysis were investigated. The dose rates in the reference case and major nuclides and each waste group were calculated. The maximum dose of each analytical case (sedimentary rock and crystalline rock) showed one figure increased more than that of basic case (10-9m/s permeability coefficient and 100 m migration distance). (S.Y.)