Study on waste acceptance criteria for waste packages destined for near surface disposal containing radioactive waste from research, industrial and medical facilities; Minimization of the amounts of scattering radionuclides caused by dropping impact

Nakata, Hisakazu ; Okada, Shota; Amazawa, Hiroya; Sakai, Akihiro 

Radioactive waste packages, which Japan Atomic Energy Agency (JAEA) plans to dispose of, must meet the technical criteria specified by the Order of Nuclear Regulation Authority. One criteria is newly specified in 2019 such that it shall be impact resistant performance so as to be few in quantity of radionuclides released from the waste package in case of dropping from the maximum height assumed in the disposal process. Then, JAEA needs to prove the compliance of the waste package with the technical criteria by estimating the leakage of radionuclides. In this report, the amounts of scattering materials inside two waste packages caused by dropping impact from 8m height was estimated by numerical analysis, providing the ratio of the amounts of scattering materials to the weight of the waste package. The analysis objects were 1m cube container-filled and solidified waste package containing metal waste, which are expected to emplace into a vault-type disposal facility. Some considerations relating to the production method of the waste package using 1m cubic container and its waste acceptance criteria are provided on the basis of the drop analysis in this report.