Safety review of reactor at Tsuruga nuclear plant halted over data tampering

The Nuclear Regulation Authority on Wednesday decided to suspend its safety screening of a reactor at Japan Atomic Power Co.’s Tsuruga nuclear power plant in Fukui Prefecture after data tampering was found in documents submitted to the regulator.

The NRA will maintain the suspension of screening, which is a prerequisite for restarting the No. 2 reactor at the plant, until it confirms the credibility of data provided by the company and the effectiveness of preventive measures.

The data tampering was discovered in a diagram containing geological information obtained from a drilling survey conducted at the plant’s premises.

A team of experts set up by the NRA had pointed to the possibility of an active fault underneath the No. 2 reactor building at the nuclear plant.

When the diagram was presented at an NRA screening meeting in February last year, it came to light that descriptions seen in the previous version had been deleted or modified without any explanation.

The agency halted screening after the data tampering was discovered, but decided to resume the process in October after the nuclear operator presented raw data from a company that had conducted the geological survey.

Although Japan Atomic denied any intention of falsifying the data, the NRA secretariat conducted an on-site inspection of the company’s headquarters and said in an interim report that the company’s task management was inappropriate. The agency began to consider halting the screening process again in July following the interim report.

At the NRA’s regular meeting on Wednesday, Chairman Toyoshi Fuketa said materials for its reactor screening meetings must be based on basic scientific methods.

“As long as there is scope for further checks, we cannot hold a screening meeting,” Fuketa said.