Development of safety assessment method for human intrusion scenario in Japan, 2; Development of a human intrusion scenario evaluation code in radioactive waste disposal (Contract research)

Takeda, Seiji ; Sasaki, Toshihisa*; Nagasawa, Hirokazu; Kimura, Hideo

In deep geological disposal or intermediate depth disposal, human intrusion, i.e. accidental excavation or drilling into the disposal site, may make a direct or indirect effect on the disposal system. Assessment of the human intrusion would need the examination of institutional control to reduce the probability of the intrusion occurring, the estimation of its probability, and the development of method to estimate its associated exposure of persons, as well as some foreign countries. Assuming that drilling action into the disposal site especially leads to the human proximity to the radioactive waste or the damage to the barrier system (drilling scenario), we have developed the evaluation code of radiological effect from the human intrusion into radioactive waste disposal system (HUINT). The evaluation code of human intrusion scenario, HUINT, can calculate the radiation exposure dose for the workers of a series of actions accompanied with drilling and for the workers and public people concerned with the reuse of drilling cores, identified with the actual information on drilling action in Japan. This report provides the descriptions of mathematical models on the drilling scenario, input specification and user information for execution of HUINT (user manual), and the result of verification for calculation with the models in HUINT.