Posts Tagged IAEA

‘Melt-through’ at Fukushima? / Govt report to IAEA suggests situation worse than meltdown : National : DAILY YOMIURI ONLINE The Daily Yomiuri

Would the Japanese public have ever heard of this if the government didn’t have to submit this report to the IAEA? What do you think, boys and girls? I’ve been tagging these kinds of news articles as “news” and “Fukushima” and “nuclear”, but perhaps I should also be tagging them “culture”, as in “culture of secrecy, hiding, denial and lying.”

Nuclear fuel in three reactors at the Fukushima No. 1 nuclear plant has possibly melted through pressure vessels and accumulated at the bottom of outer containment vessels, according to a government report obtained Tuesday by The Yomiuri Shimbun.A “melt-through”–when melted nuclear fuel leaks from the bottom of damaged reactor pressure vessels into containment vessels–is far worse than a core meltdown and is the worst possibility in a nuclear accident.The possibility of the situation at the plant’s Nos. 1 to 3 reactors was raised in a report that is to be submitted to the International Atomic Energy Agency.

via ‘Melt-through’ at Fukushima? / Govt report to IAEA suggests situation worse than meltdown : National : DAILY YOMIURI ONLINE The Daily Yomiuri.

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2011/03/31 13:00 – No Immediate Plan To Expand Evacuation Zone Despite IAEA Findings: Edano

(2011/3/31 11:36 is the time stamp for the (original?) Japanese article. Nikkei English articles do not have a time stamp.)

TOKYO (Dow Jones)–Japan has no immediate plan to expand the evacuation zone around the Fukushima Daiichi nuclear power plant despite finding higher-than-permitted levels of radiation in a village 10 kilometers away from the current zone, chief government spokesman Yukio Edano said Thursday.

The International Atomic Energy Agency said overnight that one of its teams had detected radiation from cesium-137 that is double their recommended limit in the town of Iitate, 40-kilometers northwest of the Daiichi plant.

The IAEA said the sampling was done from March 18-26 in nine municipalities.

However, a spokesman for the Nuclear and Industrial Safety Agency said at a morning news conference that authorities are reviewing whether to evacuate residents from the town.

via 2011/03/31 13:00 – No Immediate Plan To Expand Evacuation Zone Despite IAEA Findings: Edano.

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IAEA Briefing on Fukushima Nuclear Accident (27 March 2011, 13:30 UTC) (3)

Again, I’m not clipping the whole report, here. No dramatic changes. Which is good news of a kind. I’m heartened to hear of the presence of IAEA teams. I don’t trust TEPCO. I think they’re out of their depth.

IAEA Briefing on Fukushima Nuclear Accident (27 March 2011, 13:30 UTC)

1. Current Situation

The situation at the Fukushima Daiichi plant remains very serious.

The restoration of off-site power continues and lighting is now available in the central control rooms of Units 1, 2 and 3. Also, fresh water is now being injected into the Reactor Pressure Vessels (RPVs) of all three Units.

Radiation measurements in the containment vessels and suppression chambers of Units 1, 2 and 3 continued to decrease. White “smoke” continued to be emitted from Units 1 to 4.

Pressure in the RPV showed a slight increase at Unit 1 and was stable at Units 2 and 3, possibly indicating that there has been no major breach in the pressure vessels.

At Unit 1, the temperature measured at the bottom of the RPV fell slightly to 142 °C. At Unit 2, the temperature at the bottom of the RPV fell to 97 °C from 100 °C reported in the Update provided yesterday. Pumping of water from the turbine hall basement to the condenser is in progress with a view to allowing power restoration activities to continue.

At Unit 3, plans are being made to pump water from the turbine building to the main condenser but the method has not yet been decided. This should reduce the radiation levels in the turbine building and reduce the risk of contamination of workers in the turbine building restoring equipment. Read the rest of this entry »

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Fukushima Daiichi Nuclear Accident Update (25 March, 15:45 UTC) (Facebook)

There is an interesting and apparently well-informed discussion going on on the IAEA facebook page.

Specifically, there is some discussion about entombment (I blogged about this earlier, but the discussion doesn’t end there, it continues):

  1. Unfortunately, you can’t entomb live/melting reactors—-they would have to explode/burn off a large amount of material before they could bury the rest without a criticality. For example, clean up crews at Chernobyl stated at least 70% of it’s reactor had vaporized before entombment(contrary to official reports).
  2. Chris Ilderton ‎”The Science Guy’ on CNN is still spouting about cementing/entombing the reactors(while they are in the process of melting) Anyone got data on maximum tempature a fully molten core CAN reach?? I’m not thinking concrete is going to hold up.
    11 hours ago ·  
  3. Chris Ilderton I’ve heard 4 to 6,000 Farenheit for a fully molten core
  4. Chris Ilderton Apparently, If the Uranium melts, 2800c, the carbon and stainless steel or any amounts of concrete isn’t going to stop it from heading toward a large enough underground water source to cool it. Not good. Besides the Cladding breaking down/melting, what are the next signs to look for, especially if we don’t have access to temp reading?
  5. ‎@Chris (and everyone else), if a meltdown occurs, it will stop at some point, and that should be well before it escapes the bottom of the containment, here’s why. As it heats up and melts the Zircaloy cladding, it’ll pool up in the bottom …of the RPV. It will also melt some of the control rods, which adds hafnium and boron, both asborb neutrons and slow the reaction. If it’s still hot enough to melt through the bottom of the RPV, it will fall into the dry well. Each time it melts something, all that additional material gets mixed in with the fuel making it harder to sustain a reaction. At some point, it has absorbed enough steel, boron, zirconium, hafnium, and other materials that the reaction stops and it begins to cool (very slowly). more

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Fukushima Nuclear Accident Update Log

This is very good. I’ve added the IAEA website to my list of sources.

Fukushima Daiichi Nuclear Accident Update (23 March, 20:00 UTC)

Brief update on state of Fukushima Daiichi reactors

Japanese authorities today announced a number of developments at Fukushima Daiichi nuclear power plant, where reactor cooling systems were disabled following the massive earthquake and tsunami on 11 March.

At Units 1, 2, 3, and 4, workers have advanced the restoration of off-site electricity, and the lights are working in Unit 3’s main control room.

Black smoke was seen emerging from the Unit 3 reactor building, spurring the temporary evacuation of workers from Units 3 and 4. The emission of smoke has now decreased significantly.

via Fukushima Nuclear Accident Update Log.

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