LATEST: Fire erupts again at Unit 4 | PM: 'Radiation levels now danger to human health'; All but 'critical' workers evacuated from plant; Evacuations expanded, citizens asked to remain indoors; Fire at Unit 4; PM asks for calm | Unit 2 explosion heard in suppression chamber | Fuel rods half exposed ; Core containment vessel may have been damaged...
Latest UPDATES added to bottom of article...
By Brad Friedman on 3/14/2011, 4:46pm PT  

[* * * 7:50pm PT UPDATE: PRIME MINISTER'S 'MESSAGE TO NATION': Radiation levels rising, now risk human health, evacuations expanded See THIS UPDATE below for full details]

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I was working on an UPDATE (not finished yet), concerning Fukushima Daiichi's reactor Unit 2 on last night's live blog thread following the explosion at Unit 3, when news just broke at 6:14am local time, that there has now been an explosion at the Unit 2 reactor.

The new explosion follows two others, said to have been hydrogen explosions first at Unit 1, and then Unit 3 a day later, and news late last night that the emergency cooling system at Unit 2 had been damaged during the Unit 3 blast, resulting in the uranium fuel rods at 2 becoming dangerously, and completely exposed for a number of hours before sea water injection was resumed in hopes of cooling the number 2 reactor.

Now, according to various reliable sources on Twitter over the last few minutes...

"@thedeadhandbook: NHK: "A big sound" at Unit No 2. Half of fuel rods 2.7 meter length is exposed."

"@thedeadhandbook: NHK: operators evacuated from the site 'just in case.' Damage to "pressure suppression room"

"@Reuters: Fresh explosion heard at stricken Japan reactor http://reut.rs/gQJl88"

"@norishikata: We need to very closely watch what is happening to Unit 2. Most workers on-site evacuated, with minimum staff remaining."

"@AkikoFujita: Explosion at Reactor unit #2 at 6:10am. Gov't: "Radioactive levels up, but level not immediately harmful to human bodies."

"NHK: NISA says rad levels not high to cause damage to human health, but if containment vessel damaged could be serious consequences"

In the case of Units 1 & 3, according to Japanese officials, the containment vessels housing the fuel rods were not breached, though "partial meltdowns" of at least some of the rods was being presumed. Whether or not that is the case again in Unit 2, now remains to be seen...

4:57pm PT: More now, still troubling, from NHK's coverage of the Tokyo Electric Power Co. (TEPCO) news conference, as tweeted by @TheDeadHandbook...

"NHK notes there is a danger of contaminated water leaking out. still need to bring up water level. "a very serious situation"

"NHK: TEPCO: reporters pressing for information about possible damage to containment, but answers were vague."

NHK: showing chart again that blast was in bottom of vessel, indicating something wrong in last line of defense"

"NHK: nuclear expert says plunge in pressure means there could be damage to vessel. the last line of defense. very serious"

"NHK: nuclear expert says does not mean immediate leak of radiation. water injection will continue."

"NHK: nuclear expert notes that pressure in vessel was brought down to accomodate injection of water"

IDG News Services Tokyo bureau chief Martyn Williams, also covering the TEPCO news conference, adds:

"Tepco erred by starting with apology - making it seem big increase in seriousness - then unable to follow with simple explanation"

The Daily Yomiuri adds:

"Water levels are reportedly being restored at the No2 reactor at the Fukushima No1 nuclear plant. Rods now 2.8m exposed."

"Radiation levels outside the main gate of the Fukushima No1 nuclear plant were reported as 16 times normal levels."

Very good video coverage in English on NHK World streaming here...

5:14pm PT: Communications Director for PM's office, Noriyuki Shikata, tweets:

"Please do not try to physically approach Unit 2 of Fukushima Daiichi for media coverage or other purposes.

"TEPCO says, the number of remaining workers on-site Unit 2 is around 50 people."

5:46pm PT: VOA's Steve Herman tweets that the Kyodo News Agency is reporting: "Fukushima's No. 2 reactor container damaged, radiation leak feared."

To explain that concern very quickly, there are several containers around the nuclear fuel for the reactor. The fuel itself is inside rods, which are, in turn, inside a steel reactor vessel currently filled --- or partially filled, in this case --- with sea water, to try and cool the fuel rods. The steel reactor vessel is inside a concrete containment structure. If the steel reactor vessel and the concrete containment structure, "the last line of defense from keeping the fuel from being released," have, in fact, been damaged by the explosion, radioactive fuel could leak into the environment."

Still trying to get hard confirm whether the vessel was breached (unlike at Units 1 & 3 before, where officials say the container was not breached when they had their own explosions previously.)

"This is a very serious situation" and could be a "worst case scenario", according to the TEPCO official who gave a press conference within the past hour.

"There seems to be some faults with the compression pool," which is the container vessel, reports NHK.

6:04pm PT: Here is Kyodo's actual, one line report on damage to the reactor Unit 2 container vessel:

TOKYO (Kyodo)--Radiation is feared to have leaked after the container vessel was damaged at the No. 2 reactor of the Fukushima nuke plant Tuesday morning, Tokyo Electric Power Co. (9501) said.

6:46pm PT: Here is AP's report on the suspicion of damage to the reator container at Unit 2:

Japan suspects nuclear reactor container damaged
March 14, 2011, 8:39PM

TOKYO - Japan's nuclear safety agency says it suspects an explosion at a nuclear power plant may have damaged a reactor's container and fears a radiation leak.

An agency spokesman, Shigekazu Omukai, says the nuclear core of Unit 2 of the Fukushima Dai-ichi plant was not damaged in the explosion early Tuesday.

But the agency says it suspects the bottom of the container that surrounds the generator's nuclear core might have been damaged.

Another agency spokesman, Shinji Kinjo, says that "a leak of nuclear material is feared."

IDG's Martyn Williams reports that NHK says Japan's Prime Minister Naoto Kan will have a "'message to nation,' rather than news conference" at 11am local time (2am GMT / 7pm PT).

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7:50pm PT: PM'S "MESSAGE TO NATION": FIRE NOW BLAZING AT FUKUSHIMA DAIICHI UNIT 4 | DANGEROUS LEVELS OF RADIOACTIVITY DETECTED 'HARMFUL TO HUMAN HEALTH' | MOST WORKERS EVACUATED FROM PLANT | EVACUATION ZONE EXPANDED TO 20KM | THOSE INSIDE 20KM TO 30KM ZONE ASKED TO STAY INDOORS

Here are the specific details, as I was able to tweet them during the live press conference by Prime Minister Naoto Kan, which just ended. The following are all direct quotes, or as close as I was able to get them, from the PM, as the presser was translated by NHK World news agency:

"Please listen to my message calmly" ... "Every possible method used to cool down all three reactors." ... "There is a fire at Unit 4 and we've had explosions at units 1,2 & 3" ... "Radiation has spread from these reactors and reading of levels seems very high" ... "Still further risk of radioactive material coming out" ... "We need now for everybody to move out of 20km from plant." ... "We would like to you to remain indoors at home or offices and avoid going outside from the 20km to 30km radius" ... "Everybody move out from 20km radius at Fukushima-2 (Daini) plant" ... [Note: As I understood that, references to Fukushima-2 (Daini) were first ones. Previous problems were at Fukushimi-1 (Daiichi)] ... "This is a situation of serious concern. But I request that you react very calmly." ... Takes 1 question: You have not talked about Unit 2 reactor. Kan: "Rather than talk abt each indvdl reactor, I talk about whole picture" ...

Kan then turned it over to Chief Cabinet Secretary Yukio Edano. Here is what he said:

"Some new developments since I spoke at a press conference this morning." ... "TEPCO will announce specific radiation figures" ... "Number 4 reactor is now seeing a fire. It had been out of operation at time of quake" ... "No fuel rods in reactor" in 4, but "used spent fuels are in the reactor, hydrogen generated, explosion, No. 4 burning." ... "Fallen objects fell inside reactor 4, so instead of burnoff like 1 & 3, now a fire in 4" ... "Since Hydrogen being released, wee assume that radioactive substances also being released" ... "With regard to No. 2, sound of blast heard this morning. 30 minutes after No. 4 reactor" ... "Hole observed in No 2, so little possibility of hydrogen explosion. Happened while I was holding press conf this morning" ... "We believe cooling is effectively being done at 1, 2 & 3, next prob how to maintain this cooling" ... [Note: Earlier I tweeted an AP report, quoting an expert who estimated 50 gallons of water per minute needed to cool EACH reactor] ... "As of 6am, 800 member staff, all but 50 needed to inject water have been evacuated" ... "Situation I'm reporting is of very high concern and I regret reporting this." ... "Now that we see these new developments, as PM said in msg, in 20-30km area, stay indoors" ... "When staying indoors, please keep the windows shut. Do not use ventilation equipment" ... "Further you move from plants, radiation will become lower. Beyond 20 km reduced much, human health minimal or none" ... "...But depends on wind direction. So please stay indoors." ... Q: Is vessel being damaged at this moment? "1,2,3 certain level of water has been maintained, pressure stabalized." ... Q: Is fire at 4 more serious than incident at 2? "It occurred first, so I mentioned it first" ... Q: Any damage to to vessel container? "High probability that some portion of vessel damaged" ... "Fire (at 4) is an ordinary fire. Eminating heat. Radioactivity likely to be released." ... "Not type of fire to ignite hazardous materials. Operators working to extinguish." ... "Experts say those w/in 30k radius should be to evacuate. Decision to stay indoors made by PM, based on experts." ... "Concerning current radiation level readings, asked those at 20k to evacuate, at 30km to stay indoors based on experts" ... "Spent fuel is not going to catch fire, in a general sense. Fire (at 4) is in bldg area." ... Refers to Tokyo Electric Power Co. (TEPCO) for current readings of radiation levels. ... RT @nytimes: Japan faces prospect of nuclear catastrophe. Workers leave Fukushima plant: http://nyti.ms/fw5tFO ... "Cities outside Fukushima area, keep calm and we can continue with our daily lives. Levels of radiation will not cause damage to human health."

9:05pm PT: VOA's Steve Hermans says Tokyo Electric Power Co. (TEPCO) reporting "Fire at No.4 reactor apparently put out."

9:50pm PT: This happened just after the press conference, but didn't get to post it here at the time. Komonews, via Akikofujita reports: "News outlets - ABC, CNN, Sky News, ITN, BBC - moving teams away from Fukushima plant as precaution."

A few minutes later, CNN's Anderson Cooper tweeted: "Due to safety concerns we are leaving this area an therefore not live for the second hour"

10:28pm PT: In their latest of what seem (to me anyway) to be very slow and very sparse updates, the International Atomic Energy Agency (IAEA) describes the Unit 4 fire, as announced by the PM, and what it is/was causing, like this:

Japanese authorities also today informed the IAEA at 04:50 CET that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant is on fire and radioactivity is being released directly into the atmosphere.

Dose rates of up to 400 millisievert per hour have been reported at the site. Japanese authorities are saying that there is a possibility that the fire was caused by a hydrogen explosion.

3/15 1:06am PT: This will hopefully be our final update for tonight.

Chief Cabinet Secretary Yukio Edano once again addressed reporters just now. This time, the news was a bit less grim. He said that radiation levels at the Fukushima Daiichi gate had come down to where one hour equals about one year of normal exposure. That, he said, should not be a danger to human health for now. He said he was "relieved" a bit by that news. Pressure in the containers was also not giving indications that radioactive substances were leaking more than before. He had to confirm, but believe it remains low. He also confirmed that the fire at Unit 4 was now out.

The New York Times covered the earlier "Message to the Nation" by the Prime Minister with the appropriately grim headline "Japan Faces Potential Nuclear Disaster as Radiation Levels Rise".

You can check their coverage, to see how it compares to ours above, but here is some important analysis from their article, of the challenges ahead as we wrap our own coverage tonight:

The two critical questions over the next day or so are how much radioactive material is spewed into the atmosphere, and where the winds carry it. Readings reported on Tuesday showed a spike of radioactivity around the plant that made the leakage categorically worse than in had been, with radiation levels measured at one point as high as 400 millisieverts an hour. Even 7 minutes of exposure at that level will reach the maximum annual dose that a worker at an American nuclear plant is allowed. And exposure for 75 minutes would likely lead to acute radiation sickness.

The extent of the public health risk depends on how long such elevated levels persist — they may have declined after the fire at No. 4 reactor was extinguished — as well as how far and fast the radioactive materials spread, and whether the limited evacuation plan announced by the government proves sufficient.
...
“We are on the brink. We are now facing the worst-case scenario,” said Hiroaki Koide, a senior reactor engineering specialist at the Research Reactor Institute of Kyoto University. “We can assume that the containment vessel at Reactor No. 2 is already breached. If there is heavy melting inside the reactor, large amounts of radiation will most definitely be released.”

Another executive said the chain of events at Daiichi suggested that it would be difficult to maintain emergency seawater cooling operations for an extended period if the containment vessel at one reactor had been compromised because radiation levels could threaten the health of workers nearby.

If all workers do in fact leave the plant, the nuclear fuel in all three reactors is likely to melt down, which would lead to wholesale releases of radioactive material — by far the largest accident of its kind since the Chernobyl.

Even if a full meltdown is averted, Japanese officials have been facing unpalatable options. One was to continue flooding the reactors and venting the resulting steam, while hoping that the prevailing winds did not turn south toward Tokyo or west, across northern Japan to the Korean Peninsula. The other was to hope that the worst of the overheating was over, and that with the passage of a few more days the nuclear cores would cool enough to essentially entomb the radioactivity inside the plants, which clearly will never be used again. Both approaches carried huge risks.

Finally, as we started today (see the "3/14 3:53pm PT" update in our previous live blog article) thinking of the workers, at the Fukushima Daiichi plant and "the hell" they are likely "staring down into right now", we'll end on a similar note. An earlier article from the New York Times today focused on the radiation exposure they are likely to be facing and how long they can keep it up.

That task is made even worse tonight, as the Prime Minister announced that the staff was being cut from 800 down to all but 50 of the most essential workers to continue pumping water into the reactors to try and cool them down, even now as the radiation levels could rise again as they were earlier tonight.

"The workers are performing what have been described as heroic tasks," Henry Fountain writes, "like using fire equipment to pump seawater into the three failing reactors to keep the nuclear fuel from melting down and fighting the fire at a fourth reactor. They are operating in places that have been contaminated by radioactive isotopes from all four reactors."

He then offers this said thought:

Arnold Gundersen, a consultant who worked in American plants nearly identical to the stricken Japanese ones, said it was likely that the company was calling in retirees and workers from unaffected plants for help. And perhaps for sacrifice, as well. “They may also be asking for people to volunteer to receive additional exposure,” he said.

"For sacrifice". For their country.

And we were beginning to get weary of blogging this mess for four days and nights straight. In light of the above, it seems the least we can do.

Hope it has been helpful to all of you as well.

Unless it's otherwise necessary, we'll stand for the night here. Though, as needed, we'll continue coverage on Twitter right here: @TheBradBlog. Night.

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3/15 4:06pm PT: NHK reports that fire erupts again at Fukushima reactor 4 in pool where spent fuel rods are stored, radiation levels rising following the hydrogen blast there, site inaccessible to fire fighters due to radiation...

3/15 8:06pm PT: Smoke seen billowing from Unit 3, government spokesman Yukio Edano says workers at the Fukushima plant evacuated. Details on that and his press conference now in this new thread...

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