Study plan on biosphere assessment for geological disposal of radioactive waste; 5-year plan for fiscal years 2010-2014

Kato, Tomoko ; Itazu, Toru; Suzuki, Yuji*

As the biosphere assessment of geological disposal covers an extremely long time period, it is difficult to predict the future human environment and lifestyles. IAEA-TECDOC addresses that a stylized approach is proposed for selecting critical groups and biospheres in future situations where human behaviour or biosphere conditions cannot be known with any certainty, although it is possible to construct biosphere models based on the characteristics and evolution of the surface environment at the actual site in shorter time period. BIOMASS methodology is especially effective for treating uncertainty of biosphere in these situations. To address the approaches of biosphere modelling, time period after closure of repository was divided; period 0 to 100 years, 100 years to 10,000 years and beyond them. Critical issues of biosphere modelling were specified through summarising the past progresses in domestic and foreign institutes. Based on the critical issues specified, 5-year research plan on biosphere assessment were identified.