DOE OSTI2018
With funding from the Government of Canada, and support from the U.S. Nuclear Regulatory Commission's (NRC's) Office of International Program and many others, the International Atomic Energy Agency (IAEA) is supporting the field deployment of the Borehole Disposal Concept (BDC) for secure disposal of radioactive sources in Ghana, the Philippines and Malaysia. This is a first-of-its-kind implementation. Though small in volume, disused sealed radioactive sources can be intensively radioactive and create a significant safety and security liability for the majority of the 168 Member States in the IAEA. Millions of sealed radioactive sources have been manufactured since 1901, and it is estimated that hundreds of thousands are now unwanted. The irony is that some of the countries with the smallest inventories have the greatest difficulties managing their radioactive wastes. The BDC was originally conceptualized in an IAEA-study undertaken by the South African Nuclear Energy Corporation (NECSA) for countries with small inventories of disused sealed radioactive sources. There are multiple, passive engineered and natural barriers in the BDC design, including an inner stainless-steel capsule (which holds the wastes), an inner cement containment barrier, an outer stainless steel container and outer backfill cement, as well as the surrounding geosphere. In common subsurface geochemical environments, these barriers will isolate the wastes from the biosphere, provide effective containment and ensure long-term safety. To greatly limit the likelihood of inadvertent human intrusion (safety), and deliberate human intrusion (security), these waste packages will be disposed of in a narrow diameter borehole (26 cm) at depths greater than 30 m. This type of borehole disposal creates an exceptionally small footprint, removes the wastes from normal human surficial activities, and isolates the waste packages from near-surface processes. Over the past 20 years, the IAEA, NECSA and many others have advanced the BDC on the shoulders of the IAEA's broader work supporting safe and secure disposal of radioactive wastes and management of sealed radioactive sources. With recent funding and support from many others, the IAEA has assisted Ghana, Malaysia and the Philippines in assessing their inventories and conditioning their disused sealed radioactive sources, in drilling investigation boreholes and characterizing their proposed sites, and in designing their disposal systems. These countries plan to place the uppermost waste package at depths greater than 100 m. While activities in the Philippines remain focused on-site characterization, Ghana is in the latter stages of developing their Safety Case for operational and 'post-closure' safety and Malaysia has completed their Safety Case and submitted a license application to construct and operate a BDC facility. Though this paper identifies the support provided to Member States by the IAEA, it is the Ghana Atomic Energy Commission and the Malaysian Nuclear Agency that are responsible for the safety and security of the disposals and that have been responsible for carrying-out their disposal programs. Once the BDC is licensed by the relevant national regulatory bodies, these first-of-a-kind disposal approaches will provide a template for other countries to safely dispose of their disused sealed radioactive sources - permanently eliminating their safety and security liabilities. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗