TOKYO (Kyodo) — A government task force on the Fukushima nuclear crisis was found Wednesday to have rewritten the starting time of venting radioactive vapor from a troubled reactor the day after the catastrophic earthquake and tsunami without any clear explanation.
The change was made March 27 on the website of the prime minister’s office to “10:17 a.m.” from “2:30 p.m.”
Hironombu Unesaki, professor at the Kyoto University Research Reactor Institute, said the change, without any adequate explanation to the public, poses a problem as information on venting is “important in connection with residents’ exposure to radiation.”
A spokesperson for the Nuclear and Industrial Safety Agency said the agency had maintained from the beginning that venting work started at 10:17 a.m. at the No. 1 reactor of the crippled Fukushima Daiichi nuclear power station.
As the prime minister’s office posted the time at 2:30 p.m. on its website, “We pointed it out and the office changed it,” said the spokesperson of the agency under the Ministry of Economy, Trade and Industry.
While the revised information on the website mentions 10:17 a.m. as the time when “venting procedures started” instead of “venting started,” the official said the agency will ask the office to clarify the difference.
Actual venting to lower pressure in the No. 1 reactor is believed to have started after the second valve of the containment vessel was opened at 2 p.m.
According to the agency, the first valve of the vessel was manually opened shortly after 9 a.m. and work to open the second valve started at 10:17 a.m. But as mechanical problems made it impossible to confirm that the second valve had been opened, a hastily procured air compressor was used and the release of vapor was confirmed at 2:30 p.m.
Although pressure in the No. 1 reactor dropped, the building housing it was subsequently damaged by a hydrogen explosion.
(Mainichi Japan) April 7, 2011
Source: The Mainichi Daily News