10 Mars 2016
March 10, 2016
A survey by the operator of the damaged Fukushima nuclear plant shows that information on a cooling system at one of the reactors was not shared by plant workers at the time of the 2011 accident.
Meltdowns took place at 3 of the plant's reactors, starting with the No.1 unit. The complete loss of power at that reactor stopped all of its cooling systems.
Surveys in the year after the accident by the government, Diet, and Tokyo Electric Power Company showed that staff at the reactor did not know whether an emergency cooling system was functioning after an indicator lamp went off following the loss of power.
Different findings were obtained in a survey carried out last year by TEPCO.
One worker said he himself stopped the cooling system just before the loss of power. Another said he thought the system had not been functioning, because pressure inside the reactor was rising after the power went out.
The manager on duty at the time said he had no memory of being informed that the complete loss of power had shut down the system.
Just before the loss of power, the system was turned on and off to cool the reactor in stages.
TEPCO officials say reactor staff may have failed to share important information on the status of the cooling system amid confusion over the loss of power.
A later analysis shows that the meltdown started at the No.1 reactor in the evening of March 11th, the day of the accident.
But members of a task force set up that day believed that the cooling system was working until midnight. They included then plant chief Masao Yoshida.
The 2015 findings suggest that the delay in sharing the correct information may have affected the response to the accident.