Smoke is visible at TEPCO's Niigata nuclear plant but "no radiation" released: https://mainichi.jp/english/articles/20170223/p2g/00m/0dm/083000c
NIIGATA, Japan (Kyodo) -- Smoke emerged at a service building of the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture on Thursday but it quickly halted after a firefighting effort by workers, its operator said.
Tokyo Electric Power Company Holdings Inc. said there was no radiation leak in the incident. The utility has not identified the cause of the incident.
The plant operator confirmed smoke coming out around 3:25 p.m. from a locker room inside the service building, located near the No. 6 and No. 7 reactors at the plant. The building is not a radiation controlled area, according to the company.