The Nuclear Regulation Authority (NRA) has started working on legal revisions to effectively eliminate the limit on the operational life span of nuclear reactors.

The NRA appears to be responding to growing calls for the “revival” of nuclear power generation within the government and the business community. The NRA was set up as a highly independent nuclear safety watchdog in line with lessons gleaned from the 2011 Fukushima nuclear disaster. It should not forget its original mission.

The legal life span of a nuclear reactor is 40 years in principle but can be extended to 60 years at a maximum.

But the Ministry of Economy, Trade and Industry (METI), acting at Prime Minister Fumio Kishida’s behest, has proposed increasing the life span of reactors. Acting in tandem with the government’s move, the NRA instructed its Secretariat, a government agency, to review the current rules.

In a recent meeting on this issue, the NRA Secretariat presented a proposal which would require reactors that have been in service for 30 years to undergo inspections for signs of degradation at intervals of 10 years or less to win permission for continued operation. As long as they keep passing these periodical inspections, they can run beyond the 60-year limit.

The NRA is expected to work out, possibly by the end of the year, an outline of a draft revision of the Nuclear Reactor Regulation Law for the extended operations of nuclear plants.

The 40-year cap was a rule established under a bipartisan agreement reached through Diet debate that focused on the bitter lessons from the triple meltdown at the Fukushima No. 1 nuclear power plant in 2011. This rule, along with the suspension of new construction and expansion of nuclear power plants, played an important role in reducing the nation’s dependence on atomic energy, a policy goal adopted by the government. The rule must not be changed without national debate after only 10 years.

The NRA argues that whether to extend the legal life of reactors is a policy decision concerning the use of nuclear power that is outside its mandate. That means the NRA’s mandate is to ensure proper regulations of nuclear power generation according to the government’s policy.

At a glance, this position appears to be based on the principle of the separation of nuclear safety regulation from the government’s policy to promote nuclear power generation. But it is, in effect, regulation in line with promotion.

Nuclear power plants inevitably wear down over time. There are many plant parts that were not designed to be replaced. As the initial design philosophy for reactors has become outdated, the risk of unexpected problems and malfunctions increases. The 40-year rule was partly aimed at avoiding such unclear and unpredictable risks.

Extended life spans will inevitably increase the burden of inspections and raise the cost of electricity generated by aging reactors due to costs incurred by taking the necessary measures to pass inspections. This also raises questions about whether extended operations of reactors will make economic sense.

The NRA claims the regulations for reactors that have run for 30 years or longer would become “far more rigorous than now” under the proposed change. Some NRA experts have said the new system should make it harder for older reactors to pass inspections. Others have pointed out the importance of responding to the risks posed by natural disasters like earthquakes, tsunami and volcanic eruptions.

But the specifics of the new regulations and operational rules remain unclear. The ongoing policy debate on the issue, clearly driven by arguments for promoting nuclear power, raises doubts about whether the government could develop a new regulatory system that can win the support of the residents and administrations of host communities and the public as a whole.

To prevent another nuclear tragedy, it is vital for the NRA to remain solidly committed to maintaining its independence. Serious doubt about its independence would deliver a huge blow to its credibility with society.

If its independence is undermined, the NRA might be unable to resist future political pressure for relaxing the safety regulations or safety inspections of aged and risky reactors.

The NRA must realize that the situation poses a critical test of its commitment to its core mission as the nuclear safety watchdog.

--The Asahi Shimbun, Nov. 5