BOREHOLE DISPOSAL OF SPENT SOURCES: IMPROVING SAFETY ASSESSMENTMETHODOLOGIES THROUGH INTERNATIONAL EVALUATION

摘要

In 1997, the International Atomic Energy Agency undertook a Coordinated Research Programmeto review and enhance postclosure safety assessment approaches and tools for near-surface wastedisposal facilities. The new Programme was appropriately called Improvement of SafetyAssessment Methodologies (ISAM). One objective of the ISAM Programme is internationalapplication of the elements of the safety assessment approach to three test cases. Specifically,methodologies developed under three work groups-- scenario generation and justification,modeling and data, and confidence buildingare applied to three safety cases: (1) anengineered VAULT disposal design; (2) a RADON type facility, such as that in Russia; and (3) adisposal BOREHOLE design studied as an Africa region project. This paper focuses on theapplication of the methods developed in ISAM to the later Borehole Safety Case (BSC). TheBSC is based on the Borehole Disposal of Spent Sources concept intended to provide Africancountries with a solution for the long-term management of their spent sources. The BSC is beingconsidered for intermediate-depth borehole disposal, 40 to 100 meters, of an inventory rangingfrom short- to long-lived radionuclides. The hypothetical geosphere and biosphere