A Japanese court on Tuesday issued an injunction to prevent the restart of two reactors citing safety concerns, in a blow to Prime Minister Shinzo Abe's push to return to atomic energy four years after the Fukushima crisis.
It is the second court ruling in less than a year against reactors operated by Kansai Electric Power, the country's most nuclear reliant utility before Fukushima.
Local residents had sought an injunction against the No. 3 and 4 reactors at Takahama, arguing that restart plans underestimate earthquake risks, fail to meet tougher safety standards and lack credible evacuation measures.
A court official confirmed the ruling to Reuters, but did not provide details.
Public broadcaster NHK Television said the ruling stated that safety at Kansai Electric's Takahama plant west of Tokyo cannot be assured and the regulator's standards "lack rationality."
The ruling places a question mark over Japan's beefed up nuclear safety after Fukushima.
The reactors, located on the coast of Fukui prefecture in western Japan, have met safety regulations set by Japan's nuclear regulator and were expected to be restarted some time this year.
Kansai Electric said it would appeal the decision, but it could mean months, even years of delays and hundreds of millions of dollars in losses for the utility, which is about to report a fourth annual loss since Fukushima.
Shares in the utility initially fell after ruling, before rebounding.
For Abe, resuming nuclear power - which supplied nearly one-third of Japan's electricity pre-Fukushima - is key to lifting the world's third-biggest economy out of two decades of anaemic growth.