Oi reactors face new NRA safety regimen

Pair can stay on till September if they get the OK


The Nuclear Regulation Authority will start the process Friday to assess whether the nation’s two operating reactors can meet new safety requirements coming into force in July.

If the NRA acknowledges that the reactors at Kansai Electric Power Co.’s Oi plant in Fukui Prefecture have no serious safety problems, they will be allowed to remain online through September, when they have to undergo mandatory inspections.

The new regulatory requirements are being introduced in response to the 2011 Fukushima nuclear crisis. The Oi reactors are the only ones that will undergo the safety assessments before the revisions take effect.

All commercial reactors were halted after the disaster started at the Fukushima No. 1 plant.

Reactors 3 and 4 at the Oi plant, however, were reactivated last July after they cleared provisional safety standards created by the government at that time.

They are still the only reactors operating, but they have to be checked to determine whether they can meet the new safety requirements to continue operating until their routine checkup period arrives, at which point they will be halted.

The fresh regulations, drafted by the NRA, urge utilities to take specific measures to protect their plants from tsunami and to prevent or minimize the consequences of severe accidents.

Preparing an emergency response center that will not be affected by any earthquake or tsunami are among the requirements, but Kansai Electric plans to use a quakeproof meeting room in Oi as a substitute until a seismic-isolated building is completed in fiscal 2015.

The two reactors are located on ground higher than the worst assumed tsunami in the area. Kepco also plans to complete a seawall by next March.

Utilities will also be asked to equip reactors with filtered venting systems to reduce radioactive substances when gas and steam need to be released to prevent damage to containment vessels. But they will be allowed to spend up to five years installing the systems for pressurized water reactors, including the two reactors in Oi.

Tepco restarts pumping

Tokyo Electric Power Co. on Tuesday started transferring radioactive water from one of the three leaky sunken reservoirs at the Fukushima No. 1 nuclear plant to a more reliable container.

Tepco plans by the end of June to empty four sunken reservoirs holding about 23,000 tons of heavily contaminated water.

The water, which has been seeping into the soil, will be transferred both to existing containers and tanks that will be newly installed above ground.