"Cooling water injections into the No. 3 reactor of the Fukushima No. 1 nuclear power plant in northeastern Japan were halted for about an hour Monday morning ... Tepco was unable to inject a sufficient amount of water for cooling the No. 3 reactor, which suffered a nuclear fuel meltdown when the plant was damaged in the March 2011 earthquake and tsunami ... water injection pump for the reactor stopped operations shortly after 10 a.m. A secondary pump was activated about an hour later. ... pump went offline after a worker’s elbow hit the cover of a switch, damaging it and causing the switch to turn off ... also said that it suspended the cooling system for a shared spent fuel storage pool for reactors 1 through 3 after finding that an air removal valve was left open ... reactivated the cooling system about 6½ hours later ... There was no major change in radiation levels at the plant"
http://www.japantimes.co.jp/news/2016/12/05/national/fukushima-reactor-cooling-halted-staff-error/#.WEXLpFzp7rN