Two reactors on the Sea of Japan coast in Niigata Prefecture, run by the operator of the crippled Fukushima nuclear plant, cleared government safety standards on Wednesday, becoming the first of the utility’s idled units to pass tightened screening.
The Nuclear Regulation Authority endorsed a draft document that serves as certification that Tokyo Electric Power Company Holdings Inc.’s Nos. 6 and 7 reactors at the Kashiwazaki-Kariwa power station have met the new, stricter safety standards introduced after the 2011 Fukushima disaster.
The two reactors are the newest among the seven units at the complex, one of the world’s largest nuclear power plants, with a combined output capacity of 8.2 million kilowatts.
Despite the effective approval by the nuclear regulator, the actual restart of the reactors is unlikely for another few years, as Niigata Gov. Ryuichi Yoneyama says it will take “around three to four years” for the utility to win local consent for the restart.
Formal approval by the nuclear watchdog is expected after hearing public opinion and consulting with the economy, trade and industry minister to confirm that Tepco is fit to be an operator.
The clearance of the two units is likely to be a boost for the government of Prime Minister Shinzo Abe, which is keen to retain nuclear power generation despite Japan experiencing the world’s worst nuclear disaster since Chernobyl at the Fukushima No. 1 nuclear complex in March 2011, triggered by a massive earthquake and tsunami.
Tepco, facing huge compensation payments and other costs stemming from the Fukushima crisis, has been desperate to resume operations at its idled reactors so it can reduce spending on costly fossil fuel imports for non-nuclear thermal power generation.
It filed for safety assessments of the two idled reactors at Kashiwazaki-Kariwa in September 2013.
In addition to assessing technical requirements, the NRA review focused on whether Tepco is qualified to once again operate a nuclear power plant as it struggles with work to scrap the Fukushima No. 1 complex — an effort expected to take until around 2051 — and reduce contaminated water around the crippled plant where radiation levels remain high.
The two Niigata units are boiling-water reactors, the same as those that experienced meltdowns in the Fukushima crisis. No other reactors of this type have cleared Japan’s safety standards since the Fukushima disaster, partly as major refurbishments are required to boost safety measures.
Under the new safety requirements, boiling-water reactors must be equipped with filtered venting systems so that radioactive substances are reduced if gas and steam need to be released to prevent damage to containment vessels.
The venting facilities are not an immediate requirement for pressurized-water reactors as they are housed in containers larger than those of boiling-water reactors, which allows more time until pressure reaches problematic levels within the containers.
In the review, the regulator questioned Tepco on its approach to ensuring the safety of the units. The company last month agreed to a request from the regulator to include a safety pledge as part of its legally binding reactor safety program.
Safety programs drawn up for reactors need to be approved by the regulator. If it finds a grave violation, it can demand the utility halt nuclear power operations.