A Japanese court will rule later on Tuesday on an injunction request against reactors owned by Kansai Electric Power, in a case that could derail Japan's slow return to nuclear power after the 2011 Fukushima disaster.
The ruling will have ramifications for attempts by Prime Minister Shinzo Abe, a strong proponent of atomic energy, to revive the world's third-biggest economy after two decades of anaemic growth.
A panel of judges is due to rule on the injunction request against Kansai Electric's Takahama reactors west of Tokyo at 0500 GMT.
The head of the panel, Justice Hideaki Higuchi, is regarded as a maverick in the highly conservative judiciary and already ruled against the restart of another Kansai Electric plant in May last year.
Legal efforts by Kansai Electric to have Higuchi and the two other judges on the panel removed failed last week, when a high court rejected an appeal to overturn a lower court's dismissal of a move to unseat them.
Two of the Takahama reactors, with a capacity of 870-megawatts each, have received the first approvals in a three-step process and may restart later this year, unless the court blocks this.
A ruling against the reactors could keep the restart tied up in years of litigation as Kansai Electric is expected to appeal the courts decision but the appeals process takes time. It may also affect the outcome of other rulings in a country that was the third-biggest user of atomic energy before Fukushima.
Public Opposition
Kansai Electric, Japan's most nuclear dependent utility before Fukushima, is forecasting an annual loss of 161 billion yen ($1.33 billion) because of the cost of burning fossil fuels for power generation, bringing losses since Fukushima to 744 billion yen.
The company, which raised prices by 14 percent this month for its corporate customers, serves Japan's second most important economic region, where companies including Panasonic Corp and Sharp Corp are headquartered.
The country's biggest business lobby Keidanren is a strong supporter of a return to nuclear power and wants power bills cut, but Abe needs to tread carefully because opinions polls show consistent public opposition to nuclear power.
Japan's judiciary - which typically sided with power companies before the 2011 Fukushima nuclear disaster - may be shifting its attitude.
In ruling against Kansai electric's Ohi plant Higuchi delivered a scathing critique of the risk management of Japan's nuclear industry.
Judges are now considering injunctions that could halt the restarts and indefinitely extend the countrywide shutdown of Japan's 43 operable reactors that followed Fukushima.
Another court ruling is expected next week for two other reactors in southwestern Japan though legal experts believe that case may go in favour of the local utility.
Slowing down restarts would also further complicate Abe's plan to reduce imports of more expensive thermal fuels by reinstating nuclear power, which previously supplied nearly a third of Japan's energy.
Japan has been importing record amounts of liquefied natural gas (LNGLF) and coal to fill the gap for power generation, pushing the country into a record deficits.
Imports of LNG and coal are expected to stay high unless Japan moves to start more than a few reactors, analysts have said.
($1 = 120.6600 yen)
(By Mari Saito and Kentaro Hamada; Additional reporting and writing by Aaron Sheldrick; Editing by Ed Davies)