Confusion spread, tempers flared and disaster loomed at two reactors of the Fukushima No. 1 nuclear plant, nearly two weeks after the crisis started in March 2011, footage of the plant operator’s teleconferences showed.
Confusion spread, tempers flared and disaster loomed at two reactors of the Fukushima No. 1 nuclear plant, nearly two weeks after the crisis started in March 2011, footage of the plant operator’s teleconferences showed.
At issue were whether to vent the No. 1 reactor after its internal pressure neared the limit and how to keep the temperature in the No. 5 reactor under 100 degrees.
Tokyo Electric Power Co. on Jan. 23 released to reporters 312 hours of videos of teleconferences between March 23 and 30 and April 6 and 12, 2011.
At 11:20 a.m. on March 23, 2011, Masao Yoshida, then chief of the Fukushima No. 1 plant, asked the Tokyo head office to confirm procedures for venting a containment vessel.
“It will be an extremely major issue, and we need to coordinate with the head office,” Yoshida said.
At that time, pressure at the No. 1 reactor was climbing to the maximum level the reactor was designed to withstand. The pressure did not fall until the night of March 24.
At 8:58 p.m. on March 23, another serious problem was revealed when a report said temperature could rise again in the No. 5 reactor. The temperature had fallen below 100 degrees three days earlier.
A cooling system stopped working when its power was being switched from a temporary-use diesel generator to a permanent outside source.
“Something may be wrong with a motor or a power source of a pump,” an official said. “We are trying to determine the cause.”
If such temperatures rise above 100 degrees, the pressure and water levels in the reactor must be re-adjusted.
Yoshida was furious because he had not received the report immediately.
“This is a very, very important issue,” Yoshida said. “If there is something abnormal, tell us without delay. It is the most basic of basic actions.”
At a meeting in the morning of March 24, another report said the No. 5 rector would be repaired by noon. But the repairs were not completed until past 4 p.m.
“The pump rotated at 4:14 p.m.,” an official said. “Water temperature remains low at 99 degrees.”
The videos also showed that TEPCO officials failed to take effective measures for two weeks after receiving a report that highly radioactive water could be flowing into an ordinary drain at the plant.
Plant officials reported to the Tokyo head office on March 25 that water was apparently flowing out of the No. 2 reactor building via a hatch for large equipment.
Officials detected radiation levels of 40 millisieverts per hour, four times higher than surrounding areas.
But traces of water were again found at the same location 13 days later. They appeared to show that water went through the hatch and fell into the drain.
The water had almost all evaporated, but radiation levels were 50 millisieverts per hour.
A plant official said the space under the hatch’s door would be sealed with concrete or through other measures the following day.
In the videos released on Jan. 23, TEPCO beeped out audio in 1,133 cases and blurred images in 347 cases.
The videos released by TEPCO so far cover the initial one month after the Great East Japan Earthquake and tsunami crippled the nuclear plant on March 11, 2011.
TEPCO said it is considering whether to release videos for the following period.
(This article was compiled from reports by Takashi Sugimoto and Toshihiro Okuyama.)