The Hiroshima High Court said the operators Shikoku Electric and the Japanese Nuclear Regulation Authority underestimated the risk posed to residents by a possible eruption of the Aso volcano, located about 130 km from the Ikata plant, Efe news quoted public broadcaster NHK as saying in a report.
In December 2017, the court had ordered the suspension of reactor no. 3 at the plant for the same reason, and became the first Japanese high court to question the new safety requirements implemented in the country in the wake of the Fukushima nuclear disaster in 2011.
However, in September 2018, the court accepted the operator's appeal because the risk of volcanic eruption was very low, thus allowing the company to restart operations in October of that year.
This time, the court took into account the allegations made by a group of residents from Yamaguchi prefecture - located adjacent to the plant - who again highlighted the risks arising from a possible eruption of Mount Aso.
Reactor no. 3 at the Ikata plant was one of the few in the country that had received permission to operate under post-Fukushima regulations, although it was temporarily shut down on account of an inspection by the operator.
Shikoku Electric said it would appeal against the court's decision that has dealt another legal setback to the plans of the Japanese operators and the government to gradually reactivate the reactors that meet the new safety requirements.
The Fukushima disaster triggered a massive review operation of all the nuclear plants and set off new and stricter security regulations in Japan.
Tokyo estimates 20 to 22 per cent of electricity in the country will be generated from atomic plants by 2030, slightly lower than the 30 percent before the 2011 tragedy, the worst nuclear accidents after the Chernobyl disaster in 1986.
Radioactive emissions and spills from the Fukushima disaster left around 110,000 people displaced and has severely affected agriculture, livestock, and fishing in the region.
The disaster was triggered by an earthquake and tsunami that hit northeastern Japan on March 11, 2011, leaving over 15,000 people dead and more than 3,000 others missing.
( With inputs from IANS )