EXPERIENCE ON RETURN SHIPMENTS OF RESEARCH REACTOR SPENT NUCLEAR FUELS IN JAEA-TOKAI

Research Reactor Spent Nuclear Fuel (RRSNF) has successfully been transported from Japan to the United States 16 times since the foreign Research Reactor Spent Nuclear Fuel Acceptance Policy began in 1996. Of these, the Japan Atomic Energy Agency (JAEA) has carried out shipments to the US nine times, totaling 1,463 fuel elements. Several types of spent fuels generated from three research reactors (JRR-2, JRR-3 and JRR-4) have been transported from the JAEA- Tokai site. For transportation, the operator must comply with many kinds of procedures and inspections. It takes about one year to complete a shipment, including preparation works and following necessary procedures. The preparation works include evaluation of the radioactivity, cutting off the fuel nozzle and handle for fuel element, weighing each element, decontamination of the cask, etc. Additionally, there is an obligation to explain the details of the spent fuel transportation to various organizations such as local governments and fishermen's unions. In 2004, the deadline for receiving RRSNF by the US was extended to May, 2019. At the JAEATokai, the JRC-80Y-20T shipping cask was modified in 2006 in accordance with changes following a new design approach. This modification was made for the lid of the cask to mitigate impact forces under a hypothetical accident scenario. In addition, new safety analyses and designs were based on “Regulations for the Safe Transport of Radioactive Materials 1996 Edition (as amended 2003) Safety Requirement No.TS-RS-R-1” by IAEA. We will continue safe RRSNF transportation using best practices in compliance with the international nuclear non-proliferation policy, and in consideration of applicable regulations. This paper describes the practices and procedures of JAEA-Tokai concerning RRSNF transportation.