Tokyo Electric Power Company Holdings (TEPCO) postponed the restart of the No. 6 reactor at its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture.
The restart of the No. 6 reactor at the seven-unit complex was originally scheduled for Tuesday. An alarm system for the control rods, which are used to suppress the nuclear fission reaction, failed to sound during a test operation held on Saturday, TEPCO said.
The Kashiwazaki-Kariwa plant, about 220 km northwest of Tokyo, was among the 54 reactors shut down following the March 2011 core meltdowns at TEPCO's tsunami-stricken Fukushima Daiichi plant. The Niigata Prefectural Assembly approved in December the partial restart of the plant amid criticism.
Masako Murakami, secretary-general of the Citizens' Commission on Nuclear Energy in Japan, warned that TEPCO's handling of the Fukushima nuclear accident remains inadequate, leaving citizens deeply uneasy about the then planned restart of the Kashiwazaki-Kariwa Nuclear Power Plant.
"Tens of thousands of people remain in evacuation status since the Fukushima nuclear accident. There are indeed a large number of people impacted. Now, the company responsible for the accident wants to restart another nuclear power plant. What are the feelings of the victims? This is an unavoidable question," said Murakami.
In November 2025, local civic groups and governments conducted opinion polls on restarting the Kashiwazaki-Kariwa nuclear power plant. Despite a petition opposing the restart, it was rejected, and the restart proceeded.
Japan's TEPCO postpones restart of Kashiwazaki-Kariwa nuclear plant over safety concerns
