Needed: Clear roadmap to phasing out nukes

April 23, 2015

Editorial: Thorough debate on restarting nuclear reactors needed

http://mainichi.jp/english/english/perspectives/news/20150423p2a00m0na007000c.html

Courts were split over whether the green light should be given to restarting nuclear reactors at two power stations that are deemed to meet new regulatory standards set by the government's Nuclear Regulation Authority (NRA).

On April 22, the Kagoshima District Court dismissed a petition filed by residents around the Sendai Nuclear Power Plant in Kagoshima Prefecture for a provisional injunction to ban resumption of operations at the power station's No. 1 and 2 reactors.

Less than 10 days earlier -- on April 14 -- the Fukui District Court had issued a provisional injunction banning reactivation of the No. 3 and 4 reactors at the Takahama Nuclear Power Plant in Fukui Prefecture.

Behind the split in the courts' decisions are differences in basic ideas on how to evaluate the risks of serious accidents like the one at the tsunami-ravaged Fukushima No. 1 Nuclear Power Plant in 2011 and the possible impact of such disasters. The two court decisions also highlight difficulties evaluating the country's nuclear power policy. As such, the government should help deepen discussions on its nuclear energy policy to win the understanding of the general public.

The main point of contention in the two court cases was whether the biggest possible earthquake motion that the two plant operators calculated based on the new safety standards is appropriate. The quake resistance of each nuclear plant is determined based on the biggest possible quake motion estimated to hit such plants.

In their petition, residents around the Sendai plant contended that the biggest possible earthquake motion that could hit the power station is well underestimated because the figure was calculated based on the average scale of limited earthquakes that occurred in the area hosting the plant. In response, the Kagoshima District Court deemed that there are "no irrationalities" in the NRA's new regulatory standards even in light of scientific knowledge that reflects the experiences of the Fukushima nuclear disaster. The court also upheld the NRA's approval of the estimation of the biggest possible earthquake motion that could hit the power plant on the grounds that the plant operator is taking into account uncertainties involving predictions of natural phenomena in the future.

In sharp contrast, the Fukui District Court required that regulatory standards be stricter to completely prevent any serious nuclear accident and ruled that the estimation of the biggest possible earthquake motion that could hit the Takahama plant has lost credibility.

In other words, the Kagoshima District Court believes that if a nuclear reactor meets the new regulatory standards, the risks of serious accidents can be reduced to permissible levels, while the Fukui District Court is of the view that restarting any nuclear reactor is impermissible if there is any minor risk of accidents. The difference corresponds with that between members of the public over whether idled nuclear plants should be reactivated.

The presiding judge at the Fukui court who dealt with the petition for a ban on restarting the Takahama plant had also issued a similar decision in May last year to ban resumption of operations at the No. 3 and 4 reactors of the Oi Nuclear Power Plant in Fukui Prefecture.

However, the judge's decisions should not be dismissed as an extreme argument. In November last year, the Otsu District Court deemed that restarting the Takahama and Oi plants is "impossible" unless local municipalities around these plants work out evacuation plans, while stopping short of banning the resumption of operations at the power stations. Judicial rulings on the safety of nuclear plants appear to have become stricter since the March 11, 2011 outbreak of the Fukushima nuclear crisis.

The rate of an accident occurring at nuclear plants cannot be lowered to zero even if the regulatory standards are stiffened to the maximum extent. Requiring an absolute zero risk is unrealistic.

The government has reiterated that it will go ahead with reactivating nuclear reactors that are deemed to meet the new regulatory standards, but such a stance will never win understanding from the general public. If the government wants to restart idled nuclear plants, it should show a clear road map toward phasing out atomic power.