Tohoku Electric Power Company announced on November 4 that the unit 2 reactor at its Onagawa nuclear power plant in Miyagi Prefecture was shut down after 8:30 a.m. on November 4 in order to inspect a problem with measurement equipment.  
The unit 2 reactor was resumed for the first time in 13 years and seven months on October 29.
It was scheduled to restart generating power on November 3. However, at around 11:00 a.m. on the 3rd, before resuming power generation, the equipment used to measure neutrons in the reactor stopped working during operations.  The company plans to check inside the containment vessel to investigate the cause after the reactor cools down.   
There has been no leakage of radioactive materials.  Tohoku Electric Power said that it does not know when it will be able to resume generating power.