On August 21, Japan Atomic Power Co. (JAPC) announced an additional survey plan to confirm compliance of the Tsuruga Nuclear Power Plant Unit 2 (PWR, 1160MWe) with the new regulatory standards, as part of efforts to restart the reactor. On the same day, SAKAI Takeshi, head of the company’s Tsuruga Division, visited the Fukui Prefectural Government and the Tsuruga City Office to explain the outline of the plan and report it to the authorities.
In November 2024, the unit failed to obtain approval in the safety review by the Nuclear Regulation Authority (NRA), a prerequisite for restart. The NRA determined that the activity and continuity of the K fault, identified within the site’s D-1 trench, could not be ruled out.
The company intends to spend about two years from as early as September to conduct surveys and assessments of the faults and crush zones on the site, taking into account the opinions of external experts, with the aim of resubmitting its application for review to the NRA.
In the additional survey, JAPC plans to conduct deep drilling beneath the D-1 trench, where the K fault has been confirmed, in order to clarify the distribution and characteristics of the fault. The goal is to accumulate data on strata extension and sedimentation ages to demonstrate that the fault is more than 120,000 to 130,000 years old.
Furthermore, in order to demonstrate that the fault is neither active nor continuous, the company plans excavation down to the bedrock and the installation of survey piles toward the reactor building, seeking to prove that the K fault does not extend directly beneath critical facilities.