Hokkaido reactor needs construction work to satisfy new regulations

Kyodo

One of the reactors owned by Hokkaido Electric Power Co. doesn’t comply with the new nuclear regulations and will have to undergo construction work to come up to code, regulators said.

The work required for the No. 3 unit at the Tomari power plant “will not finish in several months,” the utility said Tuesday, indicating that the Nuclear Regulation Authority’s safety assessment will be protracted and the reactor’s return to operations could be facing a significant delay.

The No. 3 unit is one of 16 reactors up for NRA inspections under the safety requirements introduced last July in the wake of the 2011 Fukushima disaster.

The problem with the No. 3 reactor is in the emergency system that cools the interior of the reactor’s primary containment vessel by spraying water from a ring-shaped pipe.

The reactor only has one pipe, but the NRA said in a meeting in December with Hokkaido Electric Power officials that they need a backup system in case the pipe should break and can’t function.

Hokkaido Electric Power has insisted that such an event is extremely unlikely, but the NRA rejects this claim, saying the new safety criteria “should be strictly applied.”

It is the only pressurized water reactor undergoing the safety assessment that doesn’t have double-layered spray pipes, according to the NRA.

All 48 commercial reactors in Japan have been taken offline. To resume operations, reactors have to satisfy the new regulations.