An emergency battery was left unconnected to data transmission equipment at the Fukushima No. 1 nuclear power plant, which compounded the confusion in the early stages of the crisis, the Nuclear and Industrial Safety Agency said.
An emergency battery was left unconnected to data transmission equipment at the Fukushima No. 1 nuclear power plant, which compounded the confusion in the early stages of the crisis, the Nuclear and Industrial Safety Agency said.
The equipment was part of the Emergency Response Support System, which sends data, such as temperatures and pressure levels, about the No. 1 reactor to the central government’s reactor monitoring system, NISA said.
After power was lost at the plant at 2:47 p.m. when the Great East Japan Earthquake struck on March 11, data transmission stopped. If the battery had been connected, information from the reactor could have been obtained for the System for Prediction of Environmental Emergency Dose Information (SPEEDI), which forecasts radioactive fallout in accidents and is seen as vital in issuing evacuation orders, NISA said.
The agency said there was a 50-minute opportunity to receive such data before the entire system broke down after the tsunami hit the plant.
The battery was supposed to have been connected during Tokyo Electric Power Co.’s construction work at a building near the No. 1 reactor in November 2010.
But TEPCO said the cable was too short for the connection, and the data transmission equipment remained separated from the emergency battery because the company decided it wasn’t an urgent job, NISA said.
“TEPCO suggested installing an emergency battery,” said Junichi Matsumoto, deputy head of TEPCO’s nuclear power and plant siting division. “But there had been no clear-cut agreement on the power source for data transmission.”
NISA said it will consider making such work at nuclear power plants mandatory under law.
The connections between emergency batteries and emergency data transmission equipment were completed at the TEPCO’s Fukushima No. 2 nuclear power plant and its Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture.