The IC is an emergency cooling system.
Shortly after the quake hit the plant, engineers used the IC to cool the reactor core and turned it on and off for three times.
The government panel’s report said the engineers turned off the IC because they were trying to control the speed of the temperature drop inside the reactor no faster than 55 degrees per hour, which is stated in the manual for the IC.
But the Diet panel said the engineers told the panel that they wanted to see how the pressure level would change because they were concerned if the pressure was escaping from some cracks caused by the quake.
“It seems Tepco does not admit that the workers turned off the IC to check the leakage because it will bring up the unfavorable matter of the possibility of quake damage,” said the Diet panel, adding that it is also conceivable that the pipeline for the IC might have been damaged by the quake.
The Diet panel asked Tepco if it could send investigators inside the reactor 1 building to view the quake damage as much as possible.
But Tepco declined because the utility did not want its employees to be exposed with more radiation more than was necessary.