patrick.net

Thanks msilenus, that was exactly the type of info I was looking for.

I came across this as well:
http://www.nytimes.com/interactive/2011/03/12/world/asia/the-explosion-at-the-japanese-reactor.html?ref=asia

Step 6 details the full meltdown scenario, and suggests that a complete breach of all structures is very unlikely and *probably* not possible.

I'm pretty sure the reactors are shut down, and the rods have been removed. What's left is residue half life material breaking down, creating heat on it's own. The cooling process was there to keep that process from getting too hot. The reactor itself should be off.

Much like when you turn off a car, many modern cars keep a fan blowing to cool it off. The reactors are off, but they're still hot and they need cooling.

pkennedy says

I’m pretty sure the reactors are shut down, and the rods have been removed. What’s left is residue half life material breaking down, creating heat on it’s own. The cooling process was there to keep that process from getting too hot. The reactor itself should be off.
Much like when you turn off a car, many modern cars keep a fan blowing to cool it off. The reactors are off, but they’re still hot and they need cooling.

I think you're right that the reactors are shut down, but according to that interactive demo I posted above, however, the fuel rods are still in the reactor. The control rods have been deployed, which should slow down (and eventually stop?) the residual reactor activity, but since the fuel rods are still producing heat, without adequate cooling they may eventually melt completely.

Again, it seems that these modern reactors are engineered to contain a full meltdown, but to my knowledge this is the first time they've been put to the ultimate test. I hope they hold.

terriDeaner says

Ok, so it looks like there was a series of emergency system failures. I can see how it is difficult to plan for a series of low probability disasters… but I have to say that it is surprising that there was not a more robust safety system in place. Sort of like the scenario you suggested in your earlier comment.

Well yes and no. I think we are getting the broad strokes here and not the whole picture.

That said, I read a fascinating set of articles recently about the history of Murphy's Law. Which in it's original forms was not intended to be fatalistic. "If it can happen, it will happen" is a useful reminder about paranoia in design, quite different from the more popular versions which vary slightly but all essentially say fatalistically 'Everything that can possibly go wrong will go wrong.'"

If anyone is interested, it's a series of 4 articles linked from here:

http://improbable.com/airchives/paperair/volume9/v9i5/murphy/murphy0.html

pkennedy says

A metldown won’t be Chernobyl style either, what a meltdown in these new reactors means is that the reactors won’t be usable afterwords and will basically be entombed in their reactors. They’re designed differently now, and don’t do the same things as the old reactors would.

These *are* old reactors.

msilenus says

There probably won’t be serious fallout in Japan, let alone the United States. They’re only halfway down their list of contingencies

They've run out of options and are just pumping seawater in now and venting it into the containment building (unit 2) or open air (units 1 & 3) when the pressure gets to great. They're now debating cutting a vent into building 2 so it doesn't blow up like its neighbors.

pkennedy says

Much like when you turn off a car, many modern cars keep a fan blowing to cool it off. The reactors are off, but they’re still hot and they need cooling.

Car engines can't turn themselves back on. Reactor cores can when they melt and pool at the bottom of the containment vessel. This is the "China Syndrome" and the Mark I (old school) containment vessels were not designed to handle this.

The plant people lost cooling to Unit 2 again and there is some (dubious) reports of inability to vent the containment vessel. I don't know what its bursting point is, but a burst containment vessel would be rather catastrophic, depending on which way the wind is blowing.

I don't think this is any worse than any one of the hundreds of nuclear bomb tests the US was doing in the 1950s, but if the wind is blowing towards Tokyo that would do a number on a lot of things, since this is a close analogue of what happened at Chernobyl -- a reactor sending a cloud of nasty radioactive particles downwind.

Complicating matters is that reactor 3 was running with a 5% mix of plutonium. This has a lower melting temperature and is more likely to restart fission after melting, plus its toxicity profile is about twice as bad as the other 2 plants.

I'm 95% sure the situation won't get any worse than it is now, but this event is not over yet.

Vicente says

“If it can happen, it will happen” is a useful reminder about paranoia in design, quite different from the more popular versions which vary slightly but all essentially say fatalistically ‘Everything that can possibly go wrong will go wrong.’”

This plant is a GE design and it may have been just plopped onto its site without fully realizing the risks this site involved.

For one, I've read that the backup generators were taken out by the tsunami, and replacement generators couldn't be hooked up because the electrical switching room was *in the basement*.

D'oh! Pretty stupid contingency analysis, given that this site has 150 miles of open sea to a very active subduction fault with 10,000 miles of moving plate behind it.

That said, I read a fascinating set of articles recently about the history of Murphy’s Law. Which in it’s original forms was not intended to be fatalistic. “If it can happen, it will happen” is a useful reminder about paranoia in design, quite different from the more popular versions which vary slightly but all essentially say fatalistically ‘Everything that can possibly go wrong will go wrong.’”

Agreed. It seems to me that the point of good system design (whether mechanical or other) is to build a robustness into the system that can stand up to low probablility/high impact events (i.e., a 'black swans'), and not just to anticipate and prepare for most likely events. Same goes for the futility of trying to plan for all possible events, for that matter.

Troy says

I’m 95% sure the situation won’t get any worse than it is now, but this event is not over yet.

And it is that tail, fat or thin, that concerns me.

Troy says

For one, I’ve read that the backup generators were taken out by the tsunami, and replacement generators couldn’t be hooked up because the electrical switching room was *in the basement*.

Thank you--I've been wondering this whole time why we just didn't fly in some new diesel generators... That would make sense.

Not good news:

http://www.bbc.co.uk/news/world-asia-pacific-12733393

oh fuck.

NHK says number #2 reactor leaking contaminated water -- "could be worst case scenario for BWR in Japan" -- container vessel damage possible. "Some operators evacuated to other locations"

"Explosion in pressure suppression room" at 6:14AM

Oh, and the wind is blowing towards Tokyo now. 4.4 m/s velocity.

Fuck.

It's not really "worst case" yet.

Right now there's Chernobyl-level contamination, but only locally, unless the explosion was bigger than just a "large sound".

Worst case is the spent fuel pools in the reactors somehow losing their water levels, allowing *them* to overheat, catch fire, and spew contaminants into the air for months.

In the press conference the press person is being a jerk.

"What is the nature of the accident at this time? We are not asking your feeling . . . We want the facts. . ."

"The blast was heard near the pressure vessel . . . suppression pool pressure falling, indicating damage to the suppression pool . . . causing evacuation of the operators"

"however, other parameters have not changed greatly, water level is 2.7m under the control rods."

"Partial staff evacuation started?"

Questions about how many, when and where did the staff go?

A: "We'll get back to you on that"

Still... not good by a long shot. I hope that they are able to evacuate the danger zone quickly.

"how many people remain on site"

A: "Around 50"

That transcript doesn't give me a great deal of confidence in their information. Just makes me wonder more about what they're not willing to detail.

Losing the suppression pool container is a secondary thing -- the suppression pool is where steam collects after leaving the primary pressure container. When the suppression pool pressure gets too high they vent it outside, into the containment building (or outside, as the containment buildings for reactors 1 and 3 have been lost)

Troy says

Losing the suppression pool container is a secondary thing — the suppression pool is where steam collects after leaving the primary pressure container. When the suppression pool pressure gets too high they vent it outside, into the containment building (or outside, as the containment buildings for reactors 1 and 3 have been lost)

Secondary in terms of safety level (as in the first level of the containment vessel breached) or secondary as in not important for containment/cooling at this point?

I guess that would be the former, and more ominous, meaning of 'secondary thing':

New Blast Reported at Nuclear Plant as Japan Struggles to Cool Reactor

http://www.nytimes.com/2011/03/15/world/asia/15nuclear.html?hp

Maybe it helps filter out contaminants from the steam before it exits the plant. But nuclear plants aren't supposed to vent their steam from the suppression chamber in the first place. It's an emergency back-up, to handle pressure overflow from the main pressure chamber, to condense the steam coming out of the primary pressure vessel..

Since they can't keep the water level high enough in reactor 2's core, this implies the steam pressure in the primary vessel is too high.

What probably happened was they couldn't vent the suppression pool, and so it vented itself by failing.

900 microsieverts per hour was measured after the explosion.

By way of comparison, the hot areas of Chernobyl exclusion zone measure 300 microsieverts/hr.

This is absolutely terrifying. I don't even want to imagine what might happen if radioactive particles are blown down to Tokyo... consider that Chernobyl was essentially in the middle of nowhere and is now a ghost town 25 years after the event.

Like Chernobyl, Cesium is the primary contaminant we have to worry about I'd guess. It's got a half-life of 30 years. Coastal Fukushima is certainly fucked now.

A further problem is the reported measurement of 8 millisieverts. TEPCO didn't say where that was measured, but it was probably associated with the rupture of the separation pool. Now if they need to vent the primary reactor pressure vessel they don't have any hard containment on that, the steam will just leak out into the containment building.

This makes it difficult for anyone to be working anywhere in the building since a worker can only take 8 millisieverts for several hours before getting a cancer risk.

All this is IN ADDITION to the first reactor that blew up on Saturday and the plutonium-fueled reactor that is now "smoking".

Oh fuck. Chief cabinet secretary is talking about millisievert releases.

This is Chernobyl now, with radiation poisoning and the people working in the plant are national heroes.

Troy, are you still considering Japan as your retirement place?

Things are too bad... just too bad for them... maybe to surrouding countries... and to you.

And this from the ny times:

"The sharp deterioration came after government officials said the containment structure of the No. 2 reactor, the most seriously damaged of three reactors at the Daichi plant, had suffered damage during an explosion shorly after 6 a.m. on Tuesday.

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 disaster 25 years ago. "

I can't believe this is happening.

Tokyo Governor Ishihara may be an asshole but he recently said the tsunami disaster might wake up Japan from its greed.

This is an interesting political direction for society to explore.

Prior to Friday, Japan was both fantastically wealthy and yet so much of the rural population was simply passed by with little hope of economic opportunity. Life was pretty hard in Tohoku, people living there had to work for their money.

I don't know how bad the nuclear disaster is going to get, and I don't know which reactor situation is worse! #1 failed first and then blew up, so it might be the hottest and hardest to cool, #2 apparently has a compromised secondary containment, allow vented steam from the core to escape directly into the containment building without further buffering, #3 has 5% plutonium and the building is still smoking after it blew up, yet #4 is "on fire" and has the highest radiation readings.

The area NE of Tokyo isn't that economically productive, but it does have some established industries that would be painful to move. If Tokyo has to be evacuated

This is however a golden opportunity for Japan to stop with the bullshit and start making the really tough decisions, basically declaring war on the recession and start applying itself to create a sustainable economy without the quintillion yen national debt hanging over it.

Troy says

Like Chernobyl, Cesium is the primary contaminant we have to worry about I’d guess. It’s got a half-life of 30 years. Coastal Fukushima is certainly fucked now.
A further problem is the reported measurement of 8 millisieverts. TEPCO didn’t say where that was measured, but it was probably associated with the rupture of the separation pool. Now if they need to vent the primary reactor pressure vessel they don’t have any hard containment on that, the steam will just leak out into the containment building.
This makes it difficult for anyone to be working anywhere in the building since a worker can only take 8 millisieverts for several hours before getting a cancer risk.
All this is IN ADDITION to the first reactor that blew up on Saturday and the plutonium-fueled reactor that is now “smoking”.

I'd have to agree, the plutonium and cesium would be the immediate concerns. Also, radioactive isotopes of iodine and strontium will likely be present. All present long-term problems.

Troy says

This is however a golden opportunity for Japan to stop with the bullshit and start making the really tough decisions, basically declaring war on the recession and start applying itself to create a sustainable economy without the quintillion yen national debt hanging over it.

Interesting perspective. Doesn't look like they took the first steps in that direction today, though:

http://www.bloomberg.com/news/2011-03-13/japan-readies-massive-liquidity-as-boj-gauges-risk-to-post-quake-economy.html

Hard to fault them for this in the short term though as they are just trying to protect their economy from collapsing after a natural disaster. Didn't seem to work too well, however. Guess we'll see what happens in the long term.

And an even worse worst case scenario surfaces:

In Stricken Fuel-Cooling Pools, a Danger for the Longer Term

http://www.nytimes.com/2011/03/15/world/asia/15fuel.html

Spent, combustible fuel rods stored in cooling pools ABOVE the reactors could become a problem in days-weeks. If their cooling water boils away, they will become exposed to the atmosphere and can catch fire, thereby releasing large quantity of radioactive materials. Could be "worse than a meltdown", according to the article. Scary shit, period.

crap. I hadn't thought of the possibility that the spent fuel pools would evaporate.

Right now NHK is saying that this might have happened, just the spent fuel rods emit enough heat to evaporate their pools.

Somewhere in the blur of the last few hours I came across a bit of information about the #4 reactor. That was the one that was most recently on fire. Seems that they were using it for spent fuel storage instead of power generation. Perhaps its cooling pool had more spend fuel rods than the rest?

Some good news:

Fire at No.4 reactor put down
http://www3.nhk.or.jp/daily/english/15_33.html

The end of this article is cryptic though...

And:

All Fukushima No.2 plant reactors safely halted
http://www3.nhk.or.jp/daily/english/15_24.html

Note that this is #2 plant and not #2 reactor.

terriDeaner says

Moving on, the issue is whether the released radioactive material will get pushed high enough into the atmosphere and/or get dumped into the ocean and make its way here to the Pacific coast. Further, the amount and type of material are a important considerations.

Above ground testing of Megaton Nukes/H-Bombs has been going on during the 50-60s. Others into the 70s. We are still kicking!!

terriDeaner says

Fire at No.4 reactor put down

apparently the US military had a hand in that.

Maybe that's why the USS Reagan was so close to Fukushima this week . . .

This definitely got out of control. I'm a little surprised with all this time, they couldn't get power to the pumps somehow, and/or injected a new pump into the system.

Although I just read this on CNN '"The level has come down to the level to cause no harm to human health, according to the report I have received," Edano said.' It seems that the half life is fairly short for most of what got out.

Now they've got rain and snow hitting those areas hit hardest. Ugh.

terriDeaner says

bob2356 says

terriDeaner says

…and that problems from exposure to radiation do not always manifest immediately, so washing with soap and water is just a first response treatment. Is is really paranoid to CONSIDER that, given the escalating problems at the Japanese nuclear facilities, things may get bad enough that we could be adversely affected, even across an ocean?

You need to gain a much better understanding of radiation, radioactive materials, exposure levels, and effects. There are many sources of information that can explain this material if you are actually interested in facts not hysteria.

PLEASE educate me bobby. Pretty please.

Harmful radiation from a ground level event crossing 6000+ miles of ocean is so unlikely as to be up there with being hit by an asteroid. So don't worry about being adversely affected if you are sitting in the US. People on the ground within 10 km of the reactors have real reason to worry, not you.

Washing the the US personal exposed to LOW LEVEL radiation with soap and water was the correct thing to do. You get more radiation exposure on a long plane flight than these guys got.

This situation is serious, very serious. But radiation isn't some monolithic death sentence. Everyone is exposed to radiation of many kinds every day. The type of radiation, the distance from the source, the dosage, the exposure time, etc. etc. all determine the danger level. The workers in the plant are at real danger of harm if total dosages aren't measured carefully. People in the immediate area, 10 km or less, could be in danger, and have been evacuated. Outside the immediate area, 10 to 50 km, radiation levels are elevated but still in the getting an xray range, people are advised to stay indoors. People in Tokyo are in very little danger, but under the right circumstances (strong wind from the right direction) could have elevated danger levels. Is it paranoid to consider harmful effects from this event in the Us? Yes.

I am back in Japan. BTW I flew back to Japan on Swiss Air today (First class upgrade since they needed me to translate). Anyway there were 3 experts on nuclear reactors on the flight from Switzerland heading to Japan to check out the reactor in Fukushima Pref.

elliemae says

ChrisLA says

That’s not the same thing nomo. You can’t equate nuclear reactor blowing up to a nuclear bomb.

Actually, I believe that you can. And the radiation from the nuclear tests in the 50’s & 60’s can directly be linked to cancers that are devastating people to this day. There are many “downwinders” sites that discuss the compensation for the victims - it’s an ongoing concern.
However, the atmosphere would probably help to dissapate the radiation to harmless levels. It is concerning that they’re talking about more than one reactor melting down, tho. If that happens, the Japanese people are totally screwed.

Ellie it would depend on how much radiation the plant(s) throws out. Environment may not dissipate it enough, for one thing half life of Uranium they use is 244,500 years. Which means it isn't going away on it's own in our lifetime.

It will spread around, and whoever wins that lottery is going to suffer a lot. When Chernobyl blew up, entire countries near by got hit by it. People in other countries became ill and died because their immune system became completely knocked out by radiation.

I know our media dummifies everything, but there is "NO" safe amount of uranium radiation. There are consequences.

Plant name Unit MW Mfr Status

Fukushima-Daiichi

1 460 GE filling with sea water

2 784 GE, Toshiba filling with sea water

3 784 Toshiba filling with sea water

4 784 Hitachi fire extinguished

5 784 Toshiba shut down for scheduled maintenance

6 1,100 GE, Toshiba shut down for scheduled maintenance

Fukushima-Daini

1 1,100 Toshiba cooled down safely

2 1,100 Hitachi cooled down safely

3 1,100 Toshiba cooled down safely

4 1,100 Hitachi cooled down safely

(Source: Tokyo Electric Power, govt agencies and media as of 0640 GMT on Tuesday)

The premise of this thread, worrying about US fallout, is a sign of the USA total preoccupation with itself and it's poor grasp of basic science. This is far more of a blow to the JAPANESE people, their economy, and by extension I suppose global economies. Ecological disaster or cancer hazard for US is WAY down the list. I am not Japanese, never been there, but obviously they have tragically more close up experience with fallout and they do not seem from afar to be in full panic.