Japan’s Nuclear Regulation Authority (NRA) has approved an electric power company’s claim that faults running just below a nuclear plant are “not active,” without seeking further opinion from a group of experts that indicated the possibility of the faults being active in 2016.
After its decision to uphold the Hokuriku Electric Power Co.’s claim that faults running just below the Shika nuclear power plant in Ishikawa Prefecture are “not active,” the NRA on March 15 unanimously approved a proposal deeming it unnecessary to seek further opinion from a group of experts that had pointed to the possibility of the faults being active.
The new regulatory standards adopted in the wake of the 2011 Fukushima nuclear disaster defined “active faults” as faults whose possibility of having been active some time between now and 120,000 to 130,000 years ago “cannot be denied.” The new regulations forbid construction of key facilities such as a nuclear reactor building right above an “active fault.”
In 2016, an investigation team of experts compiled a report indicating the possibility that faults running below a key facility at the Shika nuclear plant were active, and this was received by the NRA. Afterwards, the Hokuriku Electric Power Co. managing the plant submitted additional material, including data suggesting that “the mineral veins of some 6 million years ago have not shifted due to the fault.” The NRA determined that Hokuriku Electric’s claim was valid in a meeting on March 3 this year.
The Shika nuclear power plant could have been decommissioned if the power company had not been able to present data showing that the fault is inactive. NRA chairman Shinsuke Yamanaka commented, “We believe the issues raised in the report have been sufficiently cleared (in the NRA’s inspection).”
(Japanese original by Junichi Tsuchiya, Science & Environment News Department)