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Sunday, March 13, 2011

Hydrogen Explosion at Daiichi Reactor Three

AND LAST UPDATE, YES, REALLY LAST - Big spike in radiation readings at Daiichi. End update, this is it folks. Again no US danger, should be no European danger, very little danger China/Koreas with this type of reactor, but people outside the evacuation area in Japan are now at risk of meaningful exposure, and the worst possible circs on the ground exist to mitigate. Very, very difficult circumstances to control this situation at Daiichi plant. Three reactors melting down at once has horrific potential.

MELT DOWN CONFIRMED AT Reactor 2 - TEPCO press conference interrupted "debris at bottom of vessel" (IMO VERY LIKELY THAT REACTOR VESSEL IS BREACHING NOW.) Also press conference confirms that if containment violation (containment vessel at 2 fails) then work to stabilized reactors 1 and 3 must cease. They will have to vent containment vessel anyway, so I would think it is too hot to continue working on reactors 1 and 3.
End last update, watch news, there is gonna be plenty of it. Pray for these people. No danger in US, but spare fuel rods were stored at 3 and apparently exited the building when it exploded. Therefore dirty bomb conditions around the area in Japan???

It's going, folks. The fuel rods at Reactor 2 are fully exposed again.
(TEPCO attributes this to a closed steam vent in the reactor) And what about reactors 1 and 3, which need constant cooling and aren't getting it? By now reactor 1 should be in trouble again.

Reactor 2 is Going To Melt Down
Fuel rods at the quake-hit Fukushima No. 1 nuclear power plant's No. 2 reactor were fully exposed at one point after its cooling functions failed, the plant operator said Monday, indicating the critical situation of the reactor's core beginning to melt due to overheating.

The rods were exposed as a fire pump to pour seawater into the reactor to cool it down ran out of fuel, Tokyo Electric Power Co. said. The firm had reported the loss of cooling functions as an emergency to the government.

TEPCO said water levels later recovered to cover 30 centimeters in the lower parts of the fuel rods.

The seawater injection operation started at 4:34 p.m., but water levels in the No. 2 reactor have since fallen sharply with only one out of five fire pumps working. The other four were feared to have been damaged by a blast that occurred in the morning at the nearby No. 3 reactor.
Just watch the news networks. This thing is going to meltdown through the reactor casing now, I bet. It's never happened before.
PS: If any of you are getting the idea that I know anything worth knowing about nuclear energy, forget it. My gig is the study of complex interrelated systems - how they work and how they fail. Which is why I try to buy the simplest cars possible.
End Update.
We are out of the failure cascade and into total disaster mode. Japan now needs to expand the evacuation area, bring in other workers who don't know the systems, bring in assets they don't have, and work in a totally hot environment.

: Yesterday the supply of seawater in the pit used to get water to pump into reactors 1 & 3 failed. Pumping was halted for about 2 hours and then resumed on 3. Today the plot thickens; the Reactor Core Isolation Cooling system failed. TEPCO press release. Reactor 2 was the one with low but stable water levels. At this point they should try the seawater/boric acid route with 2, but can they? NISA reported some much larger observed radiation figures yesterday around the perimeter at Daiichi in update 22. NISA also reports eleven injured in the hydrogen explosion at reactor 3, and claims that the evacuation is just about complete. At this point, attrition of the workers is starting to set in. There are reports out that they are venting reactor 2 to ease pressures there. Well, they're going to have to pump water in also! The hotter that thing gets the more likely hydrogen explosion number 3 is. End update.

No details yet. Reuters. Kyodo Wire. This was almost doomed to happen. More info. Info at World Nuclear News. TEPCO press release:
At approximately 11:01am, an explosive sound followed by white smoke
occurred at the reactor building of the Unit 3. It was believed to be a
hydrogen explosion.

According to the parameter, it is estimated that the reactor containment
vessel remains intact. However, the status of the plant and the impact
of radioactive materials to the outside environment are presently under

Some workers have sustained injuries. Ambulances are on their way to care
for them.

TEPCO continues to take all measures to restore the safety and security of
the site and are monitoring the site's immediate surroundings.

Other sources report eleven injuries.

another good link from neo neocon:http://morgsatlarge.wordpress.com/2011/03/13/why-i-am-not-worried-about-japans-nuclear-reactors/
Nice link,, Teri.
What's worrisome in all this is not what has happened so far. They've gone through most of the backup systems, but never had a complete meltdown. It's possible the reactor vessel on Daiichi #1 was breached, but the containment shell was not. The contaminants released have been minor, and caused by intentional venting. Daini #1, #2, and #4 might still be marginal, according to the last TEPCO press release, depending on whether they managed to cool the containment shell and restore their suppression pool function.

What concerns me at this point is what happens if there's another 7R or 8R aftershock in the next 8 hours, before they manage to achieve cold shutdown on the six problem reactors. They've lost so many systems already.
Daiichi #2 is in trouble. Lost cooling, flooding with sea water. There's far too much happy-talk in those TEPCO press releases, if you ask me.
Neil - yeah, I just saw that. I actually went to sleep.

Also, yesterday they stopped pumping seawater in both 1 & 3 for a while because the level of water in the pool was too low. Then they resumed on 3.

So now they've got to pump seawater into 1, 2 & 3?

TEPCO report
It's confusing for sure. At one point, I read that they had three of the six offline before the earthquake hit. Then they reported two were stable, and next thing we know, they're working on three? No wonder people are confused.
Teri - 3 of the 6 reactors at Daiichi were down for regular inspection. However, with this type of reactor, "down" is a relative term. You always have to have some cooling circulating because of waste products that will heat it back up.

Now of the 3 ones that were active and were shut down at the quake, all three have had exposed rods.

In Reactor 2, the rods were fully exposed for over 2 hours. The reactor 2 building is supposed to be vented to the outside, so they do not think that there will be another hydrogen explosion. However, they were having difficulties pumping the seawater/boric acid mix into just 1 and 3, so now their troubles have doubled. After they paused pumping for a couple of hours, they resumed on 3. Now they are doing 2. In the meantime, what do you think is happening on 1?

NISA is monitoring radioactive isotopes.
They are making progress on Daini, though. On the 14th they achieved cold shutdown of one and restoration of regular cooling on two, and are now working on restoring cooling function on the last of the four. They have offsite power.
I wish I could find a reliable source to monitor. I found a story that was heded "Nuclear experts (blah blah blah)." The "experts" they quoted were a nuclear arms policy guy and some flak from an anti-nuke organization. From the quotes even I could tell that neither one knew what they were talking about.

The Japanese have a cultural thing about not always telling the truth when it comes to bad news. I wonder if that's in operation here.
Gordon, it is over. They have just admitted that 2 is melting down, and since the water levels dropped, and there is debris at the bottom of the vessel, it is probably breaching now into the containment vessel.

In any case, it's very possible that work to control reactors 1 and 3 is essentially impossible. Also spare fuel rods at 3 went into the sky.

MOX fuel melts at lower temperatures!! This is good if you are trying to keep it in the reactor vessel, but it is also more toxic, so if it is already in the containment vessel I just don't know.
M_O_M, I think you're right to wonder about personnel issues. My wife's reaction to the problems on #2 was to say "they must be getting tired". They've probably got families and friends in the earthquake/tsunami zone, too. I wonder how many BWR-qualified people they've got at other facilities that can sub in?

You were right about the cascade, too, it seems. I'm not sure how to judge the risk going forward, now.
Yeah. Here you have these people who have been working in the most difficult conditons. Initially there was one death at Daini from the quake. Then there seem to have been over 15 injuries since.

Radiation levels at different times have spiked enough to mean that they should be rotating them through the area quickly. Also, there are multiple big aftershocks rocking the area, and multiple tsunami alerts.

Worse conditions cannot be imagined.

The Japanese have now asked for an international team to be brought in. But it will take a while, and I don't know that they have the time. They're still trying to cool 2, but I bet those pumps fell out when internal debris blocked them after the explosion on 3 last night.

I don't know what the pressure implications are; if the reactor vessel is breached (probably the control rod teflon seals went) then there is the hydraulics issue. A news blackout has descended, the the next 12 hours will be trying to contain the containment and control panic.

It is very important to preserve the lives of the workers who know these facilities. Their knowledge will be crucial later on.
With the problems at two separate facilities, both well inside the severe damage zone, it's got to be very difficult to even get people to the plants. And yes, the engineers have to be exhausted.

Red Cross UK supposedly blogged some of the figures for people affected in various ways by the whole event, but apparently the RCUK server has been swamped, because I can't get the page to load.

Having the Reagan battle group on site helps. A carrier battle group can succor a lot of people. But it sounds like they need another five CBGs.

Today's videos inside the stricken towns remind me of videos of German cities after the surrender in 1945. The roads are being cleared, but are lined with rubble that stretches in every direction.
Theoretically you should be able to contain this still. But theory and practice have the potential to diverge in situations such as this, and it really depends on how hot the stuff is that they are venting.

Because suppose 2 - which shouldn't have been that badly off to start with - is just a minor leak. Then they can keep working if they can get enough equipment and fuel in. They say they fixed the water supply problem.

Anyway, with any luck they'll fix the last circulation pump today at Daini, which gets that in much better shape. If they could bring people in from other facilities to operate that facility, it would free up more for Daiichi.
Gordon - the Reagan fled after chopper crews came back radio-dusty. They disposed of their clothes, washed them off with soap and water, and washed down the choppers. Then they headed out to sea further. That was probably from contamination from the explosion at reactor 3.
MoM, why do you believe there's no US danger? Here in the PacNW. I'm certainly concerned about our milk supply at least through Mother's Day if I'm counting right.

And every week this goes on is another week of suspect dairy.

We have three small children, extra heavy dairy consumers and extra sensitive to radio-iodine. In other words, a double-whammy. To be clear, I'm not panicking, but I don't think this is a non-issue either. Very glad it's spring, with lots of rain and cows not in-pasture anyway.
Allan - because the highest level of radiation yet reported right in the plant at Daiichi is 3,130 microsieverts, which is 3.1 millisieverts. Supposedly it is not staying at that level.

That is close to the total exposure an average person receives in a year, and 1/2 to 1/5th the exposure you would get in a CAT scan with well-maintained equipment. Most intercontinental flights on the northern loop give you way more than a CAT scan. People live long lives and have healthy families in places with annual exposures above 40 millisieverts annually.

But that is right in the plant itself. Just outside it is much, much less. There are no detectable levels of radiation in Tokyo, 150 miles away. You have a considerable buffer zone.

Assume the worst. Assume that all three melt down, and all three melt through the bottom of the containment vessels. (I do not believe this will happen.)

At that point, radiation exposure would be considerably higher locally. They would dump boron, concrete, sand and so forth on top, and you still wouldn't get any detectable radiation exposure.

If you want to worry about radiation exposure, check your home for radon.

The greater danger to locals is that fires or some other explosions may eject more contaminated isotopes which get in the soil and water. That is a lesser probability than meltdown of all three. We do not really know the total contamination of the area currently.

Your only worry is if somehow a significant proportion of all the stuff that's inside the reactor vessels, which are inside the containment vessels, which can be entombed if necessary, ends up in the jet stream. I cannot figure out how that could happen. Unless some idiot dropped a major bomb on the plant, which is why I do not like places like North Korea and Iran having those types of weapons. It is sure that North Korea wouldn't be participating, though, because it would get the fallout.

Whatever else we are looking at, we are not looking at a Chernobyl-type incident. It is the quakes and flood which will end up killing over 10,000 Japanese.

This is very dangerous to the people who are working to contain it. So far the radiation exposures seem limited in their effect even on those people.

Also, please remember the inverse square law.

I can almost promise you that your family's cumulative exposures from previous nuclear testing will be orders of magnitude higher than any exposure your family will get from this tragedy. Certainly exposure to medical care will be far, far higher than anything they could possibly get from this situation.
M_O_M, the one thing to worry about would be a steam explosion inside the containment vessel that blows the top off, or requires rapid venting of steam with fuel particulates in it. This requires that the molten fuel drops into a pool of water at the bottom of the containment vessel. I've no idea how to assess that likelihood at the moment.

Let's hope the boric acid and the "liquid control rod" works.
I don't think they are using liquid control rod. Just seawater and boric acid when they get enough seawater in. I don't think they had even started with the boric acid on reactor 2, because they hadn't gotten enough seawater in.

I was wondering what happens if there is a small leak in the reactor. Pressure shoots out into the containment vessel. I guess it should equalize naturally, right?

But suppose there is a small leak, and they are trying to pump seawater in, and the rods are pretty hot, so they basically vaporize it and most of it gets pushed back out?

They said they had a closed steam vent in the reactor that they thought was preventing them from getting the seawater in. I don't know. Steam should go up, even inside the reactor. But a cloud of trapped boiling steam might make it very difficult to refill with seawater.

Given that we already had cesium/iodine releases, some of the steam being vented from at least reactor one had to have some radioactive particles. The noble gases should just dissipate, but I was wondering if the gradually increasing radiation levels reported inside the plant were due to an accumulation of particles.

I have to hand it to the nuclear workers. They are being heroic about this.
World Nuclear News has a short article up about this. Pressure in the containment vessel at 2 reached 700 kpa. It's supposed to not exceed 400, I think, although other high pressures have been reported on the other containment vessels.

According to the article TEPCO told NISA that they assumed that at least some of the fuel rods had lost their cladding based on radiation levels. (At least, I'm assuming that's what "broken fuel rods" means.)

So when they vent 2 they are going to be getting some yuck back out.
PS: TEPCO says it was a battery problem that kept the steam vent closed, and by now that's supposed to be fixed.

But the 3,130 microSieverts was close to the main gate at Daiichi, which makes one wonder what the workers are getting. That was before the venting, I think. So no news isn't necessarily good news.

All Edano is now saying is that it won't be as bad as Chernobyl.
MoM, I agree with everything you say, except for treating all background radiation sources as equivalent.

The general, whole-body exposure from flying, or Homeland scanning, or dental x-rays, to pick three obvious sources, I don't think is the same as the localized thyroid exposure from radio-iodine.

And again, I'm not panicking. And I agree to-date there's nothing that's happened that would be a problem for the US, but I don't think that means we are free and clear in the PacNW.
Allan - but how does the iodine get to you across the ocean without the material reaching the jet stream?

There is definitely trace iodine around the Daiichi plant now. People in the area should be taking iodide, although not outside the evacuation area until they have readings showing a problem.

I'm waiting for the next NISA update, which should be a doozy. It's the 15th there now.

In order to pump seawater into the reactor, they need to have a pump capable of output pressures greater than the pressure inside the reactor. As the hot fuel generates steam, the pressure inside the reactor goes up and eventually exceeds the outlet pressure of the pump they're using. At that point, they have to vent steam to the containment in order to get more seawater in.

I'm not sure why they're using pumps, rather than steam injectors. Injectors may be part of that mysterious backup coolant injection system they talk about.
Well - it sounds like the management team has been changed, and given the circumstances, that's probably a good thing.
But it's too late. The containment vessel on 2 is leaking.

High radiation levels spreading out.

Kyodo News flashes that workers are leaving reactor 2 now. Some sort of explosion????

The suppression pool is at the bottom in the containment vessel.
Is that the reactor vessel or the concrete containment outside the reactor vessel?
The reported radiation levels in the plant of over 8,000 microsieverts make it appear that the containment vessel is breached. There is at least some leak. Also a sudden drop in pressure after the blast was reported looked very bad.

It happened. They now cannot work in the plant for very long. They should now try to entomb 1, 2 & 3 reactors.
You have to admire them, because the TEPCO people were still working in there trying to inject seawater in reactor 2. Some workers left, some stayed.

But it is too dangerous for them to be there very long. They announced that they got some water in, but....

It seems like only leaks and not massive breaches.
On NHK, they're using diagrams to show that the explosion breached the containment shell. No idea whether the reactor vessel is also breached, they're injecting water but not able to get the level above 50% coverage of the fuel rods.

There was a bang, and the pressure dropped from 3atm to 1atm (equal to ambient). The outer containment building does not visibly show damage, unlike the other two explosions. Supposedly, pressure is back up now--I have no idea what that means.

I'm watching NHK World. The commentators are visibly frustrated with the information they're getting from TEPCO and the JG. That's remarkable--there may be more than one kind of aftershock to all this.
Well, the valve had closed and it sounds like when they started to open it, there was sort of an explosive release.

What really matters more are isotopes, surely?

But they also have confirmed the roof blew off the spent fuel pool at 3.
Neil - more alarming, TEPCO said it saw some smoke this morning from the No 3 building.
Kan is going to talk to the public and Edano is giving a press conference. Within the hour. They're going to talk turkey, I guess.
Nother good link:
It's a simple explanation of the site and possible outcomes.
Because the timing of the radiation jump was ill-correlated with the explosion in 2 (or call it decompressive release), it seems more likely to be related to the situation in reactor 3.

Which is NOT good.
It appears that reactor number 4, (which was not operating at the time of the quake) has had a hydrogen explosion similar to numbers 1 and 3, however, rather than just blowing out the outer shell of the building, this appears to have damaged either the reactor vessel or the spent fuel pool (not clear from broadcast)and caused a fire which is now spewing radioactive material into the atmosphere. So much for the Chernobyl scenario being off the table.

They cited amounts of 100-400 millisievert (as opposed to the microsieverts used earlier). They believe it is reactor 4 that is driving this level of radiation.

They seem to be downplaying the damage that occured to reactor 2 and believe the reactor 4 is the real culprit.

They are telling people that live between 20-30km from the plant to stay indoors and not hang their laundry outside [no instructions on kissing your *ss goodbye though].
Number 4 reactor fire!!!
Yup. That's the smoke.

The cascade moved into the crash and still they do not hang it up and do what they must.

Still it should not be anywhere near Chernobyl, which was truly special.

But no one can work in those conditions. I can no longer figure out whether they are heroic or just stubborn. The whole facility is gone. Tomorrow there will be significant radiation levels in Tokyo if the wind turns. Not horrifying, but significant.
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