LATEST: 3RD EXPLOSION - THIS ONE AT UNIT 2 | U.S. 7th Fleet repositioning after exposure to radioactive cloud | VIDEO shows flash, plume | 6 workers injured, residents 'on edge', ordered to remain indoors | Officials believe reactor vessel NOT breached in hydrogen explosion, control room at unit still operational...
See bottom of article for continuing detailed UPDATES...
By Brad Friedman on 3/13/2011, 8:09pm PT  

An explosion has occurred within the past hour at the Fukushima Daiichi Unit 3 nuclear reactor in Japan. It appears to by a hydrogen explosion similar to the one which occurred at Unit 1 on Saturday. There had been reports earlier in the day that radiation had been rising at the reactor, similar to what had been reported before the earlier explosion at Unit 1.

Yesterday, the emergency cooling system at Unit 3 had failed, prompting officials to announce another "nuclear emergency" following the earthquake and tsunami that occurred in Japan one day earlier. Officials had taken the unusual measure to cool the reactor with sea water, which means it's unlikely to be usable ever again.

The previous explosion at Unit 1 is said to have destroyed the building housing the nuclear reactor --- causing what was variously described as a "partial meltdown" or "deformation" of at least one of the uranium fuel rods --- but did not breach the reactor container itself, so the release of radioactivity is said to have been minor. Officials are signaling a similar situation here.

Additional reports, updates, photos and videos on the new explosion all now being added below. Newest UPDATES at bottom...

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8:20pm PT: CNN reports officials are saying the container vessel at Unit 3, just like at Unit 1 before it, was not been breached in the blast...

8:28pm PT: From The Daily Yomiuri on Twitter: "Authorities are prohibiting people from coming within 5km of the Fukushima No. 1 nuclear power plant after this morning's two explosions." ... "6 Self Defense Force personnel and one nuclear power plant worker are unaccounted for after this morning's explosions at the Fukushima plant"

Prime Minister's communication director Noriyuki Shikata tweets:

"Chief Cabinet Secretary Edano says, in spite of the blast at Unit 3, no damage has occurred to the primary containment vessel." ... "The blast at Unit 3 is deemed to be the same kind as occurred to Unit 1 of Fukushima Power Plant I on Saturday, judging from the situation.: ... "Regarding the blast at Unit 3, there is little possibility that a large amount of radioactive materials are released to the air - Mr. Edano"

8:38pm PT: IDG's bureau chief Martyn Williams says the reactor's owners, Tokyo Electric Power Co. (TEPCO) is reporting "Three injured in Fukushima nuclear plant explosion, 7 unaccounted for including 6 SDF members."

8:54pm PT: PM's office says: "At Unit 3 of Fukushima Power Plant I, after the blast, Central Control Room is now confirmed to continue to function fine."

• Very good streaming coverage online in English from NHK World here...

9:01pm PT: AP reports...

Yukio Edano says people within a 12-mile (20-kilometer) radius were ordered inside following the blast. AP journalists felt the explosion 25 miles (40 kilometers) away.

Edano says the reactor’s inner containment vessel holding nuclear rods is intact, allaying some fears of the risk to the environment and public.

9:04pm PT: DGI's Martyn Williams: "Update on Fukushima nuclear plant hydrogen blast: 6 injured. The 7 that were unaccounted for have been located."

9:29pm PT: Grainy video of new explosion from Sky News...

9:38pm PT: From the UK's Guardian...

A spokesman for Japan's nuclear and industrial safety agency spokesman said a worst-case scenario had been avoided. But he added that residents inside the 20km exclusion zone had been ordered to stay indoors and close all windows.

10:10pm PT: CNN is reporting that officials had expected this hydrogen explosion "all day". If so, it certainly begs the question as to why 6 workers, as of now, were reported to have been injured by it.

11:20pm PT: Likely more directly related to the previous explosion, than this new one, but the New York Times is reporting that U.S. troops headed to Japan to help out may have been dosed with some radioactivity from the troubled nuke plants in Japan...

The Pentagon was expected to announce that the aircraft carrier Ronald Reagan, which is sailing in the Pacific, passed through a radioactive cloud from stricken nuclear reactors in Japan, causing crew members on deck to receive a month’s worth of radiation in about an hour, government officials said Sunday.

The officials added that American helicopters flying missions about 60 miles north of the damaged reactors became coated with particulate radiation that had to be washed off.

There was no indication that any of the military personnel had experienced ill effects from the exposure. (Everyone is exposed to a small amount of natural background radiation.)

But the episodes showed that the prevailing winds were picking up radioactive material from crippled reactors in northeastern Japan.
Blogs were churning with alarm. But officials insisted that unless the quake-damaged nuclear plants deteriorated into full meltdown, any radiation that reached the United States would be too weak to do any harm.

The rest of the piece goes on to discuss U.S. monitoring of radiation clouds which could drift eastward towards the United States.

The U.S. Pacific 7th Fleet has just released an announcement that they have "temporarily repositioned its ships and aircraft away from the Fukushima Dai-Ichi Nuclear Power Plant after detecting low level contamination in the air and on its aircraft operating in the area."

"For perspective," the statement continues, "the maximum potential radiation dose received by any ship’s force personnel aboard the ship when it passed through the area was less than the radiation exposure received from about one month of exposure to natural background radiation from sources such as rocks, soil, and the sun."

It concludes, "As a precautionary measure, USS Ronald Reagan and other U.S. 7th Fleet ships conducting disaster response operations in the area have moved out of the downwind direction from the site to assess the situation and determine what appropriate mitigating actions are necessary."

On a related note, ABC News' Akiko Fujita tweets the photo below, along with this note: "At evac center in Fukushima prefecture where [people] are getting tested for radiation. Residents all on edge."

As to the new explosion, NYTimes' Hiroko Tabuchi and Matthew L. Wald have this report:

TOKYO — A second explosion rocked a troubled nuclear power plant Monday, blowing the roof off a containment building but not harming the reactor, Japanese nuclear officials announced on public television.
“I have received reports that the containment vessel is sound,” [Chief Cabinet Secretary Yukio Edano] said. “I understand that there is little possibility that radioactive materials are being released in large amounts.”

Twenty-two people who live near the plant are already showing signs of radiation exposure from earlier radiation releases at the plant, but it is not clear if they received dangerous doses.
The government was testing people who lived near the Daiichi plant, with local officials saying that about 170 residents had probably been exposed. The government earlier said that three workers had radiation illness, but Tokyo Electric said Monday that only one worker was ill.

The article concludes by offering an explanation of where things stand at this point, and what the general challenges are that are currently being faced by workers at a number of the troubled reactors...

Technicians are essentially fighting for time while heat generation in the fuel gradually declines, trying to keep the rods covered despite a breakdown in the normal cooling system, which runs off the electrical grid. Since that was knocked out in the earthquake, and diesel generators later failed — possibly because of the tsunami — the operators have used a makeshift system for keeping cool water on the fuel rods.

Now, they pump in new water, let it boil and then vent it to the atmosphere, releasing some radioactive material. But they are having difficulty even with that, and have sometimes allowed the water levels to drop too low, exposing the fuel to steam and air, with resulting fuel damage.

On Sunday, Japanese nuclear officials said operators at the plant had suffered a setback trying to bring one of the reactors under control when a valve malfunction stopped the flow of water and left fuel rods partially uncovered. The delay raised pressure at the reactor.

At a late-night news conference, officials at Tokyo Electric Power said that the valve had been fixed, but that water levels had not yet begun rising.

11:39pm PT: Another video of the explosion gives a better sense of the scale...

11:52pm PT: Another cooling system failure at yet another reactor?

Three separate news agencies, The Dialy Yomiuri, Jiji News Agency and NHK are all tweeting that the cooling system has failed at the No. 2 reactor at the Fukushima Daiichi nuclear power plant and that water levels there are falling.

I've been unable to find confirm of that yet in any article or statement online, however.

If the report is true, that could signal that Fukushima's reactor Unit 2 could now be on track for the same fate as seen at reactor Units 1 and 3, as they each had reported similar cooling system failures about 24 hours before hydrogen levels got high enough finally to cause explosions...

3/14 12:09am PT: Okay, Reuters now runs Jiji's report here:

Cooling functions stop at Japan nuclear reactor-Jiji
Mon, Mar 14 06:26 AM GMT

TOKYO, March 14 (Reuters) - Cooling functions have stopped and water levels are falling in the No.2 reactor at Tokyo Electric Power Co's Fukumshma (sic) Daiichi nuclear plant damaged by a powerful earthquake, Jiji news agency said on Monday.

3/14 12:29am PT: Okay, NHK's streaming video news just reported:

This just in: No. 2 reactor at Fukishima Daiichi nuclear plant has lost all its coolant. Pressure inside the vessel is rising.

3/14 12:53am PT: Another video of the Unit 3 explosion. Perhaps the best view yet, with sound...

12:57am PT: Deja Deja Vu Vu: Back to Fukushima Daiichi's reactor Unit 2 which, as noted above, has now had its cooling system fail like Units 1 & 3 before it. The Daily Yomiuri tweets that the government is announcing seawater will be injected into it as coolant --- just as we saw with 1 & 3 before they eventually saw hydrogen explosions.

2:04am PT: CNN's Tokyo correspondent reports (on TV) that the failure of the cooling system in Unit 2 is due to power knocked out by the explosion in next door Unit 3, leaving Units 1, 2 and 3 at the Fukushima Daiichi's nuclear plant (sometimes called Fukushima No. 1) all now facing serious cooling problems, with pressure rising in the so-far-unexploded No. 2.

The UK's Guardian offers this "Before & After" shot of Unit 3 in its coverage of today's events...

Finally, as this may have to be my final UPDATE before standing down here for the night, unless warranted, I'll point you to this (sort of) amusing late report from the Village Voice's Roy Edroso, in which I'm mentioned in the final graf: "Rightbloggers Find the Lesson of the Japanese Disaster: We Need More Nuclear Power Plants! (Plus Obama Sux!)"

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3/14 3:53pm PT: I cannot even imagine the hell that workers at Fukushima Daiichi are staring down into right now. Last night, after my final update to this item before standing down (though my updates continued on Twitter here from bed, until about 5am PT), news broke that the fuel rods at Unit 2 had become fully exposed for a number of hours after a human error as the generators being used to pump sea water into the reactor had run out of fuel. That was/is an incredibly dangerous situation.

Later, news came in suggesting that the injection of sea water into the reactor in hopes of cooling it down had restarted, somewhat mitigating the exceedingly volatile situation --- at least a bit. For the moment, that seems to be where things stand, in general, at least publicly.

So to get us quickly caught up on this thread, as to where things stand, at least for now, here are the key issues at the moment, as I've been able to stitch them together over the past several hours. NOTE TO NEWS OUTLETS: Please include time-stamps, not just date-stamps, on your articles --- particularly during fast-breaking stories like this one! Thank you!!!

The Kyodo agency and the NYTimes seem to be offering the most timely overviews at the moment.

The Kyodo report offers a quote from Chief Cabinet Secretary Yukio Edano late last night, which may win the Understatement of the Year Award: The reactor "is not necessarily in a stable condition," he said at an early morning press conference.

They go on to report that "Prime Minister Naoto Kan said earlier in the morning that the government and TEPCO will set up an integrated headquarters, headed by himself, to address issues at the Fukushima" Daiichi plant. and that, "With radiation levels around the facility up, TEPCO suspects the core of the No. 2 reactor has partially melted, a critical nuclear safety situation."

They say that the fuel rods were fully exposed "for around two and a half hours," before sea water was injected and levels "increased temporarily but late Monday night they started dropping, leading to full exposure of the rods again."

Not good.

In the meantime, the New York Times reports that "at least parts of the fuel rods have been exposed for several hours," at Unit 2, which "suggests that some of the fuel has begun to melt," according to both government and TEPCO officials.

"In a worst case," they report, "the fuel pellets could also burn through the bottom of the containment vessel and radioactive material could pour out that way — often referred to as a full meltdown."

They go on to say that workers at the plant are in "full-scale panic":

Industry executives in touch with their counterparts in Japan Monday night grew increasingly alarmed about the risks posed by the No. 2 reactor.

“They’re basically in a full-scale panic” among Japanese power industry managers, said a senior nuclear industry executive. The executive is not involved in managing the response to the reactors’ difficulties but has many contacts in Japan. “They’re in total disarray, they don’t know what to do.”

The Times also notes: "The United States Nuclear Regulatory Commission said Monday that the Japanese government had formally asked for assistance as it responds to the crisis in Fukushima."

And, as to Unit 3, they say:

But the situation a reactor No. 3 was being closely watched for another reason. That reactor uses a special mix of nuclear fuel known as MOX fuel. MOX is considered contentious because it is made with reprocessed plutonium and uranium oxides. Any radioactive plume from that fuel would be more dangerous than ordinary nuclear fuel, experts say, because inhaling plutonium even in very small quantities is considered lethal.

In a previous thread, we had asked a nuclear expert about that claim, and he generally poo-pooed the notion that plutonium MOX fuel was anymore dangerous than uranium-based fuel, saying that "if it was substantially worse than [uranium] fuel, they wouldn't be allowed to do it. Regulations forbid it," for whatever that's worth. To see his full comments on that, see the "3/12 6:58pm PT" update on this live blog thread, created to cover the first Fukushima explosion at Unit 1 over the weekend.

The Times also updates the number of those injured at No. 3 to 11 (from 6, as reported previously), "one seriously".

Finally, investigative journalist, and former "lead investigator in several government nuclear plant fraud and racketeering investigations," Greg Palast, offers this perspective today: "Tokyo Electric to Build US Nuclear Plants: The No BS Info on Japan's Disastrous Nuclear Operators"

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3/14 5:30pm PT: * * * EXPLOSION AT REACTOR UNIT NO. 2! * * * See this new live thread for details, updates...

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