Nuclear watchdog calls on operators to install filtered venting systems

New NRA safety standards may impact reactor restarts

Kyodo

The Nuclear Regulation Authority said Wednesday its planned new safety standards to deal with serious atomic crises in the event of earthquakes and tsunami could affect the reactivation of the country’s reactors.

The NRA will solicit public comments on the standards as well as other regulations, including a process to give exceptional extension to reactors operating more than 40 years, as the country continues to grapple with the Fukushima No. 1 nuclear plant disaster triggered by the March 2011 megaquake and tsunami.

Public opinion will be courted for 30 days from Thursday and could be reflected in the standards, which will be enforced from mid-July.

The new standards will replace the current guidelines that the Fukushima catastrophe proved were insufficient.

Complying with the new standards will be a major precondition for power firms to apply for government permits to put their idled reactors back online. Amid heightened concerns over nuclear safety, only two reactors in Japan are currently operating.

Under the new safety regime, the NRA will require nuclear plant operators to install filtered venting systems that can reduce the amount of radioactive substances and lower the pressure inside a reactor container during an emergency. Fukushima No. 1 had venting systems but not with radiation-screening filters.

Earthquake-tsunami countermeasures face drastic changes. And no reactors will be allowed to be built or to operate above an active fault. The time frame used to gauge whether a fault is active will be reassessed with an eye to going back farther in history.

At present, active faults are defined as those that have moved in the last 130,000 years, but the NRA will move the benchmark to 400,000 years ago. Countermeasures for volcanic eruptions were also drawn up.

The nuclear body said a special safety inspection process for reactors running beyond 40 years will be in place, targeting one reactor at Japan Atomic Power Co.’s Tsuruga plant in Fukui Prefecture and two at Kansai Electric Power Co.’s Mihama plant, also in Fukui.

The government decided to limit the operation of reactors to 40 years in principle, but an exceptional extension of no more than 20 years is allowed when safety requirements are met.

The NRA has also revised nuclear disaster mitigation guidelines that would pave the way for local governments to brief residents and distribute iodine tablets. Doctors will explain when to take the pills and their side effects at the briefings.

The iodine tablets will be given to people living within a 5-km radius of a nuclear power plant so they can promptly take them in the event of a crisis to lessen the chance of contracting thyroid cancer in the event of exposure to radioactive iodine. The tablets will also be distributed to people beyond that radius if necessary.