Posts Tagged meltdown

Unit 3 MOX likely melted through | The Japan Times Online

MOX fuel that was believed to have been kept cool at the bottom of one of the reactors at the crippled Fukushima No. 1 nuclear plant after its core melted is believed to have breached the vessel after melting again, a study said Monday.The study by Fumiya Tanabe, an expert in nuclear safety, said most of reactor 3’s mixed uranium-plutonium oxide fuel may have dribbled into the containment vessel underneath, and if so, the current method being used to cool the reactor will have to be rethought.

via Unit 3 MOX likely melted through | The Japan Times Online.

Tags: , , ,

‘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.

Tags: , , , ,

Theme of the day – faith in government is waning

The following excerpts pretty much speak for themselves, but because this is the media speaking, take a large lump of salt with all this. I’ll add my usual pearls of wisdom after you’ve read the quotes.

“It breaks my heart that they did nothing for the children,” said Sadako Monma, herself a mother of two, who has run the Soramame center for 15 years. “Our answer was to stop waiting for someone to help us.”

Slow action by the government has set off a revolt among the usually orderly ranks of Japanese bureaucrats.

“I don’t believe the government,” said Kanako Nishikata, 33, a mother of two elementary school children here. “The air here is dirty. The soil is dirty. They are leaving Fukushima to suffer and perish.”

via In Japan, Fukushima Parents Grow Angry Over Radiation – NYTimes.com.

The figure is equivalent to 20 times the annual radiation limit for ordinary people. When releasing the statement, the ministry also did not touch on any measures to decontaminate school facilities.

Parents voiced complaints and concern. “It is a figure too high for children,” said one parent. “No specific measures have been presented,” said another.

The city of Koriyama has decided to remove top soil from school playgrounds on its own. Even so, the central government brushed aside the local government’s move. Chief Cabinet Secretary Yukio Edano said, “Based on the guideline of the education and science ministry, there is no need for removal.” Read the rest of this entry »

Tags: , , , , , , , , ,

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).
    http://en.wikipedia.org/wiki/Nuclear_meltdownSee more

Tags: , , , , , , , ,

Twitter feed – iodine 131 in Tokyo water drops

Some tweets from today, related to the post-earthquake/tsunami/Fushima nuclear reactors (what else?). First, two items that I’m sure will make all Japanese everywhere heave a big sigh of relief:

Steve Herman
 
 JMA: Yellow substance on ground in Tokyo after rain is not radioactive, it’s pollen.
(This mysterious tweet was explained by the Daily Yomiuri Twitter feed:
The govt says it’s been flooded with calls about “yellow radioactivity” falling from the sky. It’s actually just pollen http://bit.ly/fTsMHe )

via Twitter / Home.

and

Steve Herman
 USFJ: No problems found with water, food on US military bases in
 

Steve Herman also links to an article by Michio Ishikawa (Chief Adviser of Japan Nuclear Technology Institute (JANTI) in the Denki Shimbun (that’s “denki” not “genki”). Long and technical but worth reading if you are interested in how the Fukushima is similar to Three Mile Island (TMI) and Chernobyl accidents (it’s quite similar to TMI but completely different from Chernobyl). Ishikawa was himself trapped in Hitachinaka City after the earthquake and only had a radio to tell him what was happening in the outside world:

By estimating what is happening in the reactor cores of Fukushima Dai-ichi Nuclear Power Station based on the facts and developments of the Three Miles Island (TMI) accident, I would like to urgently state what are expected to happen from now on and what measures can be taken.

However, I’m now living in a disaster area of Hitachinaka City. I could not contact the outer world for three days until March 14 because of a power outage. As for news sources, I only could listen to a radio. I could eventually watch TV the night before last and knew what was happening in the world like Rip Van Winkle. So, I’m barren of specific values (information about the realities). As this report is the outline of a story reasoned from facts, I think that there are many particulars that are wrong.

Read more.

And BraveNewClimate tweets an article in Nature, that is not behind a subscription screen.

Barry Brook
Great article on in Nature (but you might need a subscription – my Uni has one…): The meltdown that wasn’t:

It will probably be years before anyone knows exactly what happened inside the three reactors at Fukushima Daiichi that seem to have partially melted down in the wake of the tsunami. But from press reports, public statements and interviews with experts, it is possible to work out the most likely scenario. And already it is clear that decisions made in the initial 24 hours by the handful of operators in the control room probably averted a much greater nuclear catastrophe than the one that now faces Japan.

In the moments after the power was lost, the operators “would have literally been blind”, says Margaret Harding, a nuclear engineer in Wilmington, North Carolina. Harding worked for two decades with General Electric, which designed Fukushima’s boiling-water reactors, and she witnessed a similar outage in 1984 during a safety test at a boiling-water reactor in Switzerland. “Basically the emergency lights came on and all the panels went black,” Harding says.

During the Swiss test, the power returned in 5 minutes. At Fukushima, batteries ran a handful of emergency lights in the control room and a few instruments tracking the reactor’s vital signs, such as the pressure inside the core.

The core was next door.

And a few more tweets just in (15:44 JST, Thursday March 24, 2011):

W7VOA Steve Herman Kyodo: Radioactive iodine in Tokyo water drops below limit for infants. #Fukushima

W7VOA Steve Herman NISA: 3 workers at Fukushima-1 over-exposed to radiation.

24 minutes ago  »

W7VOA Steve Herman

TEPCO: Radioactive iodine level rising in sea water near #Fukushima-1.

25 minutes ago  »

TimeOutTokyo TimeOutTokyo by W7VOA Tokyo’s deputy governor says the levels of iodine have dropped, more contaminated water may remain in the pipes. http://bit.ly/dHMwUW

1 hour ago  

W7VOA Steve Herman NHK: Chiba Pref. Gov’t also issues advisory on halting drinking water to infants due to radioactive iodine level.

3 hours ago 

W7VOA Steve Herman Saitama reports level excessive for infants also detected in its water supply. #Fukushima 

4 hours ago  

Tags: , , , ,