Saturday, February 11, 2017

Fukushima Daiichi: Current Conditions and Past Accounts


Fukushima emissions up again February 12, 2017 2:43:



Dry streets at the Futaba Intersection


I was looking back through my materials on unit 2, given its been featured so prominently in the news media recently, and I found this article, which is interesting to read retrospectively (please note that the link is no longer active):

Crisis continues at Fukushima nuclear plant as fuel rods exposed again. TOKYO, March 15, Kyodo http://english.kyodonews.jp/news/2011/03/77943.html

A crisis continued Tuesday at the troubled No. 2 reactor at the quake-hit Fukushima No. 1 nuclear power plant, as fuel rods became fully exposed again after workers recovered water levels to cover half of them in a bid to prevent overheating. 
The plant operator, Tokyo Electric Power Co., said a steam vent of the pressure container of the reactor that houses the rods it was closed for some reason, raising fears that its core will melt at a faster pace. It said it will try to open the vent to resume the operation to inject seawater to cool down the reactor. 
Despite its earlier attempt to do so, however, water levels sharply fell and the fuel rods were fully exposed for about 140 minutes in the evening as a fire pump to pour cooling seawater into the reactor ran out of fuel and it took time for workers to release steam from the reactor to lower its pressure, the government's nuclear safety agency said. 
Water levels in the No. 2 reactor later went up to cover more than half of the rods that measure about 4 meters at one point. TEPCO began pouring coolant water into the reactor after the cooling functions failed earlier in the day. 
Prior to the second full exposure of the rods around 11 p.m., radiation was detected at 9:37 p.m. at a level twice the maximum seen so far -- 3,130 micro sievert per hour, according to TEPCO. 
To ease concerns, Chief Cabinet Secretary Yukio Edano said he believes the problem at the plant ''will not develop into a situation similar to the (1986 accident at the atomic power reactor in) Chernobyl'' in the Soviet Union, even in the worst case. 
Officials of the Nuclear and Industrial Safety Agency also said the worst case scenario will be less destructive than the Chernobyl incident, as TEPCO has depressurized the reactors by releasing radioactive steam. 
The utility said a hydrogen explosion at the nearby No. 3 reactor that occurred Monday morning may have caused a glitch in the cooling system of the No. 2 reactor.
Similar cooling down efforts have been made at the plant's No. 1 and No. 3 reactors and explosions occurred at both reactors in the process, blowing away the roofs and walls of the buildings that house the reactors.
 
Edano denied the possibility that the No. 2 reactor will follow the same path, as the blast at the No. 3 reactor opened a hole in the wall of the building that houses the No. 2 reactor. Hydrogen will be released from the hole, he said. 
The blast earlier in the day injured 11 people but the reactor's containment vessel was not damaged, with the government dismissing the possibility of a large amount of radioactive material being dispersed, as radiation levels did not jump after the explosion. 
TEPCO said seven workers at the site and four members of the Self-Defense Forces were injured. 
Since the magnitude 9.0 quake hit northeastern Japan last Friday, some reactors at the Fukushima No. 1 plant have lost their cooling functions, leading to brief rises in radiation levels.
As a result, the cores of the No. 1 and No. 3 reactors have partially melted.

 

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