Winding down operations in January 2009, Hamaoka-1 and -2 shifted to “decommissioning” status in November of the same year, making them the first light water reactors (LWRs) in Japan to start that process. Currently they are in the first stage of decommissioning, in preparation for demolition work.
In the materials research, to be carried out in the form of participation in an IAEA international project, samples will be taken of the structures of Hamaoka-1’s main reactor body, after which changes in the material characteristics of the reactor pressure and containment vessels will be studied and analyzed. It is very rare for such tests to be conducted while reactors are still in operation.
The results will be integrated with other information and knowhow on decommissioning generated worldwide, thus contributing to further improvements in nuclear safety.
Meanwhile, research on the state of reactor radioactivity — to be carried out with the EPRI — will involve the sampling and analysis of actual materials, allowing the radioactivity distributions in the reactors to be more precisely understood. It will also enable more rational and efficient demolition work, along with better planning for the treatment and disposal of the waste stemming from that work.
