TOKYO -- A court ruling Tuesday takes a different stance from the government and electric utilities on the risk of operating decades-old nuclear reactors in earthquake-prone Japan.

The Fukui District Court's injunction against restarting two reactors at Kansai Electric Power's Takahama plant raises serious doubts about new safety guidelines that supposedly draw on lessons from the Fukushima Daiichi meltdowns.

The issue has economic consequences. A prolonged shutdown of much of the country's nuclear power capacity would drive up the already-high rates Japanese companies and households pay for electricity, experts say.

After the Fukushima disaster, Japan revamped its nuclear oversight. New safety standards adopted two years ago impose stricter requirements on reactor operators to prepare for earthquakes, tsunamis and the kind of catastrophic breakdowns that occurred at the ill-fated plant in March 2011.

The idea was to weed out unfit reactors while keeping viable ones in service to ensure dependability in the power supply and electric rates. The Nos. 3 and 4 reactors at Takahama in Fukui Prefecture had passed the Nuclear Regulation Authority's safety examination. Kansai Electric had hoped to restart them as early as November.

Enter the Fukui District Court, whose ruling Tuesday contends the new safety standards do not go far enough to prevent worst-case scenarios. As such, the reactors' safety "has not been established," the judge wrote in the ruling. Kansai Electric's assumptions of the maximum earthquake tremors "do not warrant trust" because more powerful quakes have struck other nuclear power plants, he wrote.

Although the two reactors are already among the most advanced in Japan in terms of safety measures, the court concluded that they are unfit for operation. Its ruling insists that Kansai Electric reduce the risk of accidents to virtually zero with extensive quake-proofing and other safeguards.

"Going by this ruling, no reactor in Japan could operate," a person familiar with Japanese nuclear regulation says.

The new standards require plant operators to ensure layer upon layer of fail-safe mechanisms. Even so, "there is no such thing as 100% safety," NRA Chairman Shunichi Tanaka has said.

The government's eagerness to start up idle reactors reflects a different kind of risk. Since the Fukushima disaster, Japan has imported more crude oil and liquefied natural gas as substitutes for nuclear power. Household electric rates have risen by 20%, while the price that companies pay for power has gone up roughly 30%.

"If electric rates go any higher, small and midsize enterprises and people of limited means will suffer a serious blow," warns Tadashi Narabayashi, a professor of energy and the environment at Hokkaido University.

Delayed indefinitely

The Fukui District Court's ruling marks the first judicial roadblock thrown against reactor operation in Japan.

The temporary injunction takes effect immediately. Kansai Electric may yet succeed in having the decision overruled. But at this point, there is no telling when the two reactors will resume operation. The appeal process could take a year or more and go all the way to the Supreme Court.

In addition to injunction requests, there have been three lawsuits in which residents seeking to suspend nuclear reactors prevailed against plant operators. But two of the rulings were overturned by higher courts.

(Nikkei)