Tokyo Electric Power Company says power cables caught fire at the Kashiwazaki-Kariwa nuclear power plant on the Sea of Japan coast on Thursday morning, but the fire has died down.
The plant operator reported the fire at around 6:28 AM. TEPCO said a worker had detected smoke in a pit housing power cables.
Firefighters later confirmed the fire had died down.
All 7 nuclear reactors at the plant are currently offline. Local government officials say monitoring posts have not shown any changes in radiation levels.
They will ask TEPCO about the cause of the fire.