Sunday, March 13, 2011
Hydrogen Explosion at Daiichi Reactor Three
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.
Update: 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
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
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.
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.
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?
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.
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.
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.
You were right about the cascade, too, it seems. I'm not sure how to judge the risk going forward, now.
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.
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.
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.
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.
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.
Let's hope the boric acid and the "liquid control rod" works.
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.
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.
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.
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.
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.
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.
It happened. They now cannot work in the plant for very long. They should now try to entomb 1, 2 & 3 reactors.
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.
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.
What really matters more are isotopes, surely?
But they also have confirmed the roof blew off the spent fuel pool at 3.
It's a simple explanation of the site and possible outcomes.
Which is NOT good.
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].
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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