Photo: DigitalGlobe, CC
Heroic Efforts to Cool Reactor Cores Continues
The nuclear crisis at the Fukushima Daiichi plant in Japan is still ongoing two and a half weeks after a massive earthquake and tsunami struck the area. News from last week made us optimistic that thing were getting better, but since then the news has been mostly bad. Read on for more details.
Staff Sgt. Alicia Tucker explains how and when to take potassium iodide tablets March 22, 2011, at Yokota Air Base, Japan. U.S. Pacific Command officials directed distribution of potassium iodide tablets as a precautionary measure. Base officials are stressing there is no indication of increased exposure at Yokota AB. Sergeant Tucker is assigned to the 374th Medical Operations Squadron. Photo: U.S. Air Force photo/Osakabe Yasuo, public domain
Japan's prime minister, Naoto Kan, addressed the Japanese parliament yesterday. He said: "The earthquake, tsunami and the ensuing nuclear accident may be Japan's largest-ever crisis. We find ourselves in a situation where we can't let down our guard. We will continue to handle it in a state of maximum alert."
TEPCO, the operator of the nuclear reactors at Fukushima, has announced that it would decommission 4 reactors (units #1 through #4), and would consult the local population on units #5 and #6.
Radioactive iodine-131 above regulator limits was found in seawater. Kyodo News reports that "Radioactive iodine-131 at a concentration of 3,355 times the maximum level permitted under law was detected in a seawater sample taken Tuesday". Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, said that this does not pose an immediate risk to health because Iodine 131 has a half-life of eight days, but that it isn't yet clear why levels are that high, which is a bad sign.
More dangerous to the workers on site is the radiation-contaminated water that has been filling up the lower parts of buildings and trenches at the power station, "obstructing work to restore the lost functions."
Plutonium has been detected in soil at five locations at the crippled Fukushima Daiichi nuclear power plant, Tokyo Electric Power Co. said Monday. [...]
While noting that the concentration level does not pose a risk to human health, the utility firm said it will strengthen monitoring on the environment in and around the nuclear plant. [...]
high levels of radiation exceeding 1,000 millisieverts per hour have been detected in water in a trench outside the No. 2 reactor's building at the nuclear plant, with the contaminated water suspected to have come from the reactor's core, where fuel rods have partially melted, authorities said Monday. (source)
The presence of plutonium, even in extremely small quantities, could mean that one or many containment vessels could be more damaged than previously thought. Some experts even think that the core could have melted all the way through the containment vessel and unto the concrete floor of the containment building. But there are contradictory reports on this, so we'll probably have to wait a bit to find out what the situation actually is.
Some experts worry that all the water that has been dumped on the reactor units could have caused damage to equipment, making it harder to regain control of the reactors.
Masataka Shimizu, the CEO of TEPCO, was taken to hospital on Tuesday night suffering from exhaustion, according to the Guardian.
Previous Updates on Japan's Nuclear Crisis at Fukushima
-March 14: Mini-FAQ About Japan's Nuclear Power Plant Crisis
-March 15: 6 Important Questions About the Crisis at Japanese Nuclear Power Plants
-March 16: Update on Japan's Nuclear Crisis at Fukushima I
-March 17: Ongoing Crisis at Japan's Fukushima I Nuclear Power Plant
-March 18: Japan's Nuclear Crisis, One Week Later
-March 21: Limited Progress Cooling Fukushima's Nuclear Reactors
-March 22: Light at the End of the Tunnel for Japan's Nuclear Crisis?
-March 23: Japan Nuclear Crisis: External Power Reconnected at Fukushima 1
-March 24: Japan Nuclear Crisis: Slow Progress with Emergency Cooling Systems
-March 25: Japan's Nuclear Crisis: 2 Weeks After the Mega-Quake & Tsunami
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