The first images taken from inside the pressure vessel of the No. 4 reactor at the Fukushima No. 1 nuclear power plant show damage, although the amount of debris was not as much as officials had expected.
The first images taken from inside the pressure vessel of the No. 4 reactor at the Fukushima No. 1 nuclear power plant show damage, although the amount of debris was not as much as officials had expected.
Tokyo Electric Power Co. took the images on March 15 and released them the following day.
The No. 4 reactor was not in operation when giant tsunami inundated the plant a year ago because it was undergoing regular maintenance work and inspections.
All the nuclear fuel had been moved from the reactor to a pool for spent nuclear fuel.
The images show what appear to be boards that have fallen inside the pressure vessel, apparently due to the impact of an explosion March 15, 2011, in the building that houses the reactor.
TEPCO checked the inside of the pressure vessel of the No. 4 reactor for the first time since the accident by sinking an underwater camera about 20 meters to the bottom of the vessel.
Boards that were up to about 2 meters long and debris that appears to be concrete fragments were seen on the bottom portion and also around the lid of the pressure vessel.
“The volume of debris that had fallen (in the pressure vessel) was not as much as we had expected,” said Junichi Matsumoto, acting general director of TEPCO’s Nuclear Power and Plant Siting Division.
TEPCO plans to store spent control rods at the bottom of the pressure vessel. It will also remove spent nuclear fuel from the pool at the end of 2013.