patrick.net

I've only seen a couple of good news articles on TV and they didn't really repeat. Probably because they weren't doomsday scenarios, but dealt with how these reactors are built and what would happen.

The cores have been shut down. The uranium is no longer producing heat. What is left is material that uranium breaks down into, that is producing heat still. The half life of that material isn't measured in years, it's measured in minutes and seconds mostly.

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.

There are a few good articles out there from nuclear engineers who can explain exactly what's happening inside. They aren't that hard to find either.

These are not Russian 80's designs, and it's been 4 days now. They have pretty good odds on getting it all under control IMO although it's going to be a hell of a mess to clean up afterwards. All the damage plus emergency measures taken afterwards mean even understanding how to untangle it will take a while. Doubtless this site will be shut permanently, and it's remants hauled off to other locations. I wonder that they didn't have some sort of automated SAFE SHUTDOWN though. First sign of real troubles you'd think the systems would start retracting rods etc. automatically. Guess that's got it's own problems though in a really strong earthquake.

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.

There are a few good articles out there from nuclear engineers who can explain exactly what’s happening inside. They aren’t that hard to find either.

I sincerely hope this doesn't proceed to Chernobyl stage. My concern is that since most of the well-engineered safety mechanisms have thus far failed to some degree, no one can be certain of what happens next. Could you post links to the articles you've found by the nuke engineers?

Vicente says

These are not Russian 80’s designs, and it’s been 4 days now. They have pretty good odds on getting it all under control IMO although it’s going to be a hell of a mess to clean up afterwards. All the damage plus emergency measures taken afterwards mean even understanding how to untangle it will take a while. Doubtless this site will be shut permanently, and it’s remants hauled off to other locations. I wonder that they didn’t have some sort of automated SAFE SHUTDOWN though. First sign of real troubles you’d think the systems would start retracting rods etc. automatically. Guess that’s got it’s own problems though in a really strong earthquake.

My understanding is that the safe shutdown protocol was part of the problem. That is, when the earthquake hit, there was an automatic systematic shutdown for several hours then they tried to start normal reactor operations after the preset safety shutdown period expired. Unfortunately, the power to the cooling systems did not come back on line after the shutdown period, and the secondary measures they have been using to prevent a full meltdown have apparently not been too effective...

pkennedy says

The cores have been shut down. The uranium is no longer producing heat. What is left is material that uranium breaks down into, that is producing heat still. The half life of that material isn’t measured in years, it’s measured in minutes and seconds mostly.

Under ideal circumstances, yes. But the big concern is the possibility of other, nastier radioactive materials (with biological activity and longer half-lives) escaping in large quantities in particulate form. Very difficult to clean up and very dangerous. Some of these materials can be serious trouble even in smaller doses, if they persist in the environment and have the propensity to bioaccumulate.

Hmmm, I just got around to looking for details of the failure. There's a decent summary video on CNN about 3 minutes long that outlines the chain of cooling failures.

http://www.cnn.com/video/#/video/world/2011/03/14/dnt.japan.reactor.explainer.nhk?hpt=C2

Primary cooling system shutdown due to power failure.
Shutdown of secondary diesel-powered emergency cooling system one hour after the quake, right when the tsunami struck.
The tertiary emergency system was then unable to handle the job, perhaps due to leakage from the vessel.

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.

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.

Vicente says

Hmmm, I just got around to looking for details of the failure. There’s a decent summary video on CNN about 3 minutes long that outlines the chain of cooling failures.
http://www.cnn.com/video/#/video/world/2011/03/14/dnt.japan.reactor.explainer.nhk?hpt=C2
Primary cooling system shutdown due to power failure.

Shutdown of secondary diesel-powered emergency cooling system one hour after the quake, right when the tsunami struck.

The tertiary emergency system was then unable to handle the job, perhaps due to leakage from the vessel.

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.

There probably won't be serious fallout in Japan, let alone the United States. They're only halfway down their list of contingencies, and the simplest solutions are at the end of the list. Those cost about a billion dollars to clean up after if they're needed, but they contain the damage without serious public health impact. The containment structures on these plants are designed to contain any failure up to and including a complete core meltdown.

http://www.csmonitor.com/World/Global-News/2011/0313/Japan-s-nuclear-crisis-and-Chernobyl-key-differences

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.