A malfunctioning thermometer in the damaged No. 2 reactor at the Fukushima No. 1 nuclear plant was traced to human error, and operator Tokyo Electric Power Co. said Feb. 19 there was no cause for alarm.
A malfunctioning thermometer in the damaged No. 2 reactor at the Fukushima No. 1 nuclear plant was traced to human error, and operator Tokyo Electric Power Co. said Feb. 19 there was no cause for alarm.
TEPCO said a second thermometer on the bottom of the reactor is working properly. It said the one working improperly was thrown out of action after being short circuited.
TEPCO said human error was almost certainly behind the failure.
According to officials at the utility, workers discovered the damaged instrument on Feb. 18.
The thermometer was installed after the March 2011 earthquake and tsunami that triggered the triple meltdown at the plant.
Workers doing routine instrument checks mistakenly overloaded the device's circuits, resulting in the equipment failure, TEPCO officials said.
The other temperature gauge was fitted before the nuclear crisis unfurled. The broken indicator monitored melted nuclear fuel in the process of cold shutdown as part of efforts to keep it from going critical again.