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Meltdown Likely Under Way At Japan Nuclear Reactor


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Some useful links (old and new)

- NHK world Life streaming in English: http://www3.nhk.or.jp/nhkworld/

- SPEEDI radiation level reporting: http://www.bousai.ne.jp/eng/

(reports in nGy/h, divide by 1,000 to get μSv/h)

- Life streaming Geiger counter in Chiba http://www.ustream.tv/channel/geiger-counter-chiba

(reports in μSv/h)

- Life streaming Geiger counter in Tokyo http://www.ustream.tv/channel/geiger-counter-tokyo

(reports in cpm, divide by 100 (ballpark figure) to get μSv/h)

- Prediction of movement of the radioactive particles http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-16GMT09:50

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Elcent and others, I just checked the web sites of the Navy 7th fleet and similar military sites, and I saw no mention of the post info above about the military having ferried in special generators for the nuclear plant..

It seemed the original info on that here was from an Al Jazeera blog... Does anyone have an actual military announcement about that?

There was a post a couple days ago that GE in the U.S. was preparing to send generators to Japan, being scheduled to leave starting last Wednesday, if I recall correctly.

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U.S. asks [u.S.] citizens in 80-km radius of Japan nuke plant to evacuate [or stay indoors]

WASHINGTON, March 16, Kyodo

The U.S. Embassy in Japan has asked American citizens living within an 80-kilometer radius of the quake-hit Fukushima No. 1 nuclear plant in Japan to evacuate as a precautionary measure. ''We are recommending, as a precaution, that American citizens who live within 50 miles (80 kilometers) of the Fukushima Nuclear Power Plant evacuate the area or to take shelter indoors if safe evacuation is not practical,'' the embassy said in the advice issued Thursday local time.

Conditions such as weather and wind direction will affect the area of radioactive contamination in a complex way, the embassy said, adding that low-level radioactive materials can reach areas more than 80 km away from the damaged nuclear power plant.

The Japanese government currently sets the evacuation zone covering areas within a 20-km radius of the plant and advises those within a 30-km radius to stay indoors.

http://english.kyodo...1/03/78713.html

Edited by jfchandler
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Kyodo News recap on reactor damage:

Of the six reactors at the Fukushima No. 1 [Daiichi] nuclear plant, part of the No. 2 reactor's containment vessel, key to enclosing harmful radioactive substances, has been compromised. More specifically, the pressure-suppression chamber connected to the vessel was damaged following an apparent hydrogen explosion early Tuesday.

An estimated 70 percent of the nuclear fuel rods have been damaged at the plant's No. 1 reactor and 33 percent at the No. 2 reactor, Tokyo Electric said Wednesday.

The cores of the No. 1, No. 2 and No. 3 reactors are believed to have partially melted with their cooling functions lost in the wake of Friday's magnitude 9.0 earthquake and tsunami.

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Someone asked above about the issue of the cooling pools at the other reactors besides No. 4. A bit of info on that from Kyodo News this morning:

What appeared to be smoke coming from the No. 3 reactor in the morning led the top government spokesman to point to the possibility of damage to the reactor's steel containment vessel, but it seemed more likely later in the day that the smoke was radioactive steam coming from the No. 3 reactor's spent fuel pool.

Cooling down the spent fuel pools is a difficult task amid the high radiation level in the area, while fears of radiation among the public appeared to escalate as some companies refused to deliver relief materials to Fukushima Prefecture even outside of the government-designated warning zone.

The government's Nuclear and Industrial Safety Agency said the first priority should be pouring coolant water into the pools at the No. 3 and No. 4 reactors, which are apparently boiling. Unless the spent fuel rods are cooled down, they could suffer damage and emit radioactive substances.

If cooling operations do not proceed well, the situation will ''reach a critical stage in a couple of days,'' an agency official said.

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It's interesting that the discussion seems to be turning toward the cooling pools, as opposed to the reactors themselves...

I have read some reports the past day or so, that talk about the issue of the risk in the reactors themselves lessening the more time passes since they were shut down.. In other words, the fission activity and heat should be naturally, slowly lessening with time... even in the absence of adequate cooling.

The uncooled cooling pools, however, where the nuclear fuel rods are kept in proximity to each other, appears to be a different issue.

Comments?

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It's interesting...just the other day...we had media reports quoting the British PM as saying nuclear plants and power still needed to part of Britain's energy mix.

Britain advises nationals in Tokyo, areas north to consider leaving

LONDON, March 16, Kyodo

Britain on Wednesday advised its nationals living in Tokyo and areas north of the Japanese capital to consider leaving in light of the ongoing nuclear crisis at the quake-hit Fukushima No. 1 nuclear plant in northeastern Japan. It said the British Embassy in Japan plans to arrange free buses from Sendai, Miyagi Prefecture to Tokyo on Thursday for evacuating British nationals. It also advised against all non-essential travel to Tokyo and northeastern Japan.

''For those outside the exclusion zone set up by the Japanese authorities there is no real human health issue that people should be concerned about,'' the Foreign Ministry said in a statement.

''However, due to the evolving situation at the Fukushima nuclear facility and potential disruptions to the supply of goods, transport, communications, power and other infrastructure, British nationals currently in Tokyo and to the north of Tokyo should consider leaving the area,'' it said.

http://english.kyodo...1/03/78731.html

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Official: Spent fuel rods exposed, heightening concerns

Tokyo (CNN) -- Spent fuel rods in Unit 4 of Japan's stricken Fukushima Daiichi nuclear plant have been exposed, resulting in the emission of "extremely high" levels of radiation, the head of the U.S. Nuclear Regulatory Commission said Wednesday.

"What we believe at this time is that there has been a hydrogen explosion in this unit due to an uncovering of the fuel in the fuel pool," Gregory Jaczko told a House energy and commerce subcommittee hearing. "We believe that secondary containment has been destroyed and there is no water in the spent fuel pool, and we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures."

CNN--2011--03--17

Full Story Here

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Good post... thanks Jd

Some useful links (old and new)

- NHK world Life streaming in English: http://www3.nhk.or.jp/nhkworld/

- SPEEDI radiation level reporting: http://www.bousai.ne.jp/eng/

(reports in nGy/h, divide by 1,000 to get μSv/h)

- Life streaming Geiger counter in Chiba http://www.ustream.t...r-counter-chiba

(reports in μSv/h)

- Life streaming Geiger counter in Tokyo http://www.ustream.t...r-counter-tokyo

(reports in cpm, divide by 100 (ballpark figure) to get μSv/h)

- Prediction of movement of the radioactive particles http://www.zamg.ac.a...1-03-16GMT09:50

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NHK reporting the police and their water cannon truck have arrived at the Fukushima plant....

Also talking about Japanese Self Defense supposedly sending another helicopter this morning to try to put water on the No. 3 reactor...but not clear if they've already tried that yet or not.

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The big issue with these pools is that they are not contained at all, except by the now non-functional outer structure.

The fuel rods are far further apart then they would be inside a reactor core, so it is very unlikely the will reach criticality, but without water they will start melting and can spread their contents over a large area.

As all these rods have been cooling down for quite a while, this will be even more slow-motion then inside the reactor cores. So as long as they occasionally get some water in the pools it won't be acute.

The water-cannon approach will be starting any moment now, let's see how that goes.

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It's interesting that the discussion seems to be turning toward the cooling pools, as opposed to the reactors themselves...

I have read some reports the past day or so, that talk about the issue of the risk in the reactors themselves lessening the more time passes since they were shut down.. In other words, the fission activity and heat should be naturally, slowly lessening with time... even in the absence of adequate cooling.

The uncooled cooling pools, however, where the nuclear fuel rods are kept in proximity to each other, appears to be a different issue.

Comments?

IMO... concern is turning to the cooling pools (particularly #4 which has been repacked and contains not only old but current fuel rods) because there is absolutely no containment structure around the pools. They are open to the atmosphere and contain copious quantities of radioactive materials. Studies have shown that a run-away accident in a cooling pool can be equal or worse than a core meltdown.

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The big issue with these pools is that they are not contained at all, except by the now non-functional outer structure.

The fuel rods are far further apart then they would be inside a reactor core, so it is very unlikely the will reach criticality, but without water they will start melting and can spread their contents over a large area.

As all these rods have been cooling down for quite a while, this will be even more slow-motion then inside the reactor cores. So as long as they occasionally get some water in the pools it won't be acute.

The water-cannon approach will be starting any moment now, let's see how that goes.

Except that the #4 pool contains not only 20+ year of spent fuel rods, but all the current rods from the #4 reactor which had been removed for maintenance. Further, it is feared that the pool has been re-racked (perhaps more than once) and the spacing is unclear.

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