Research on a super-long-term test of overpack materials in geological disposal environment

Wada, Ryutaro*; not registered; Nishimura, Tsutomu*; not registered; not registered; not registered; Fujiwara, Kazuo*

The overpack is expected to have long-term soundness, and corrosion behavior models of the overpack have been constructed. To verify validity and maintainability of the models, this study conducted a research on a super-long-term test of overpack materials for several decades. (1)We designed a testing device that would allow long-term monitoring of the corrosion behavior of carbon steel, an overpack candidate material, and the condition in the buffer material in an environment corresponding to the environment immediately after disposal. (2)We examined and prototyped a test container that would allow long-term immersion tests of carbon steel without maintenance operations such as solution exchange. (3)We proposed super-long-term tests (about 20 years) that would contribute to future geological disposal projects and safety rules. (4)We investigated a method for managing and preserving the records of the super-long-term test for the test period (20 years).