Monday, August 18, 2014

http://www.globalpost.com/dispatch/news/kyodo-news-international/140813/workers-try-save-fukushima-no-1-reactor-through-ventin


Workers try to save Fukushima No. 1 reactor through venting mission


Less than 12 hours after the quake-triggered tsunami hit the Fukushima Daiichi nuclear complex on March 11, 2011, Tokyo Electric Power Co. sought government approval for the unprecedented step of releasing radioactive steam from troubled reactors to reduce a dangerous buildup of pressure.
Prime Minister Naoto Kan, however, would soon become increasingly distrustful of TEPCO because of delays in starting the so-called venting operations, which were aimed at preventing damage to the reactor containment vessels.
"TEPCO said it wanted to do venting. So I told TEPCO to do it, but it didn't," Kan recalled. "I asked why, but there wasn't a reply. I thought things would go wrong if they kept going on like this."
Frustrated by TEPCO's response, the 64-year-old prime minister said in front of reporters early in the morning on March 12 that he planned to speak directly with the person responsible at the Fukushima Daiichi plant to find out exactly what was going on.
On his way to the plant on board a Self-Defense Forces helicopter, Kan bombarded Haruki Madarame, 62, a nuclear adviser to the government, with questions, such as what would happen if a reactor core melted and whether there could be an explosion.
Kan arrived at the plant shortly after 7 a.m. But he had no idea at the time that fuel was already melting in the No. 1 reactor.
"What is going on?" Kan heatedly asked plant chief Masao Yoshida, 56, at a meeting room of the emergency response office building.
Yoshida explained that the power to remotely operate valves for venting the No. 1 reactor had been lost and that workers would quickly need to manually operate the valves because of the rising radiation level inside the reactor building.
"We will do the venting. We will do it even if we have to form a suicide corps," Yoshida said. ....

 In June 2012, TEPCO found the radiation level near the No. 1 reactor's suppression chamber stood at up to 10,300 millisieverts per hour, a level highly likely to be fatal if a person stays there for an hour.

Endo's team was tasked with three missions -- to open the valve, to measure the radiation level inside the reactor building, and to return safely.
After opening the door to the reactor's building, the reading on Endo's radiation measurement device jumped to 500 millisieverts per hour. As he lit up the inside of the building with a flashlight, he saw it was filled with what looked like steam or dust...

They heard a series of large bangs in the dark -- a type of noise Endo had never heard before. The radiation meter went back and forth between 900 and 1,000 millisieverts per hour...
If the radiation level was 1,000 millisieverts per hour, Endo would have exceeded the 100-millisievert radiation dose limit a nuclear power plant worker is allowed to be exposed to in five years in just six minutes...

When the two returned to the main control room, all eyes turned to them.
"It failed. The radiation meter scaled out," reported Endo. As Endo unloaded his air tank and took off his mask, he found that he was drenched with sweat all over. During the 8-minute journey, Endo was exposed to 89 millisieverts of radiation, while his colleague was exposed to 95 millisieverts.

 In June 2012, TEPCO found the radiation level near the No. 1 reactor's suppression chamber stood at up to 10,300 millisieverts per hour, a level highly likely to be fatal if a person stays there for an hour.