The information coming out of Japan right now is very piecemeal and very incomplete. We are also depending on an organization without a stellar reputation when it comes to telling the truth[1], and a culture programmed to downplay very bad things. It has really pained me to see people rush to believe that everything is fine.
Conclusions at any stage of this crisis have been premature, but HN seems to want a heavy dose of finality to a crisis that isn't even over yet. Apparently people don't want it to be a big deal, but it's slowly turning into a big deal. It just is. Instead of big essays and conclusions about how the powers-that-be have it under control complete with inaccurate depictions of how a reactor works, why don't we focus on facts?
With that in mind, we do not know how bad it is. Anyone who says they do is lying to you. It isn't over, and it is a basic fact of logic that we will not be able to reflect on how bad this is or was until it is over.
At the risk of a neener-neener I told you so, I presented some of this viewpoint[2] on the self-aggrandizing risk management Ph.D.'s everything's fine piece, but my viewpoint was drowned out by people wanting to rush to a conclusion so they can put the crisis out of sight and out of mind.
Whether you like it or not, the beliefs of most intellectual engineer types is that the nuclear power plant dangers have been solved.
It's inconceivable (cue sound clip from Princess Bride) to most of us that extremely extensive and effective contingency plans are not in place.
The nuclear risk is obvious, and so any nuclear construction's main emphasis must be on handling all possible contingencies... right?
If Fukushima does end up being a "Big Deal" that is going to forcibly shift the world view of many many engineers and hackers. It will represent a piece of data that is fundamentally at odds with our view of the world.
The facts will eventually win out, but for the short term, it is necessary that we go through these cycles of disbelief and then shock. Because that's just reality.
I will be shocked if Fukushima causes serious harm to humans because until now it has been inconceivable to me that people making nuke plants could possibly underestimate the risks. If my inaccurate beliefs are shattered by the harsh reality of nuclear related deaths then... that's just how it will have to be. I'll have to eat my hat. I'm not looking forward to it.
In the meantime I have to go with what I know. Which is that this should not be an issue that threatens human life.
But, okay, as you wish. I have the crisis firmly in mind now. I will not "rush to believe that everything is fine" or anything.
So.
Do you have any advice about what action I should take next? I live twelve time zones away, am a citizen of a different country, and have only a passing acquaintance with nuclear engineering.
I can't accomplish anything useful by panicking. I can't change building codes from N years ago, I couldn't prosecute anyone in Japan for negligence even if I had any evidence of same (which I do not), I can't dictate to Japanese industry even if I knew what to do (which I obviously don't), I can't run the Japanese government, I can't even vote in Japan. Neither I nor anything else we know can stop radioactive elements from decaying, and I can't unwind time and stop the earthquake.
I suppose I can raise my blood pressure, and raise the blood pressure of everyone else I know, and we might even achieve mass hysteria. Is that really a good idea? Why? Like every citizen of the USA, I happen to have some experience with mass hysteria. It didn't turn out well in 2001. I'm not anxious to see more of it.
What would you like me to do, instead of waiting for events to unfold, staying away from certain portions of the Japanese coast, hoping that various Japanese nuclear engineers have done their duty well, and meanwhile focusing on other things?
While it is true that there are many people attempting to call the crisis "over" without adequate evidence that this is the case, I think it is equally obvious that there are many people who are doing the opposite: namely, attempting to make the case that the crisis is far worse than the incomplete facts indicate.
I applaud your more measured approach, but I must say that, as someone who has read most of the stories and comments regarding this topic that have hit the front page, I do feel that you are decidedly in the minority. There are plenty of people rushing to call this a horrendous disaster, who are privy to the same limited information, and who are likewise doing very little to contribute to the discussion.
> Apparently people don't want it to be a big deal, but it's
> slowly turning into a big deal.
I think that people's reactions here are because they view this as the new beachhead in the 'nuclear is evil and will destroy the world' argument.
I think that the reality probably boils down to:
It's possible to do nuclear in a safe way. It's even possible
for humans to build such a system (i.e. the complexity
is not out-of-reach), but it's possible that (like economics)
this fails to take into account how illogical humans are (e.g.
cutting corners on something that is *really* dangerous).
I think a lot of the nuclear defensiveness attitude has to do with anti-leftist conspiracy bias. There are a lot of people that think that there are giant conspiracies run by environmentalists/hippies/peaceniks etc. that are blocking human progress, such as our ability to create nuclear power utopias. Forming your worldview around these types of ideologies can be uncomfortable when it clashes with reality.
I'm not sure whether it's that "HN seems to want a heavy dose of finality..." or if we're just naturally inclined to want good news in the face of overwhelmingly bad news.
I keep on thinking of Akira Kurosawa's "Dreams..." (One of the segments deals with just this kind of scenario. The protagonist finds himself in hell after a nuclear disaster.) A horror like this has been in the cultural subconscious of Japan for decades. They always knew that there was a possibility of something like this, but they chose to gamble against it happening.
They didn't do it because they were foolish, or naive. They did their best to avert that disaster. The people had faith in the talent and skills of those engineers responsible.
It's our nature to want to see the good... even in a horror like this. (Especially a bunch of people who are willing to risk everything to start a business.)
Turns out the optimistic reports upvoted by hacker news were polyannish. There appear to be 2 borderline catastrophes right now -
1. In reactor 4 spent fuel rods are burning and radioactivity is being freely vented in to the air. NONE of the optimistic reports suggested this possibility but I see a prophetic article at http://www.nytimes.com/2011/03/15/world/asia/15fuel.html.
2. Reactor 2 has had an explosion that has damaged the core containment structure - something we were assured would not happen.
Why were engineers so optimistic, while the ground reality is so much worse? Probably the complexity of the system escapes us and look at small parts of the issue and assume they are under control. In reality many things are interacting and the combination can overwhelm defences. For eg. as water is being routed to reactors 1, 2 and 3 to prevent meltdowns, the spent fuel rods are overheating.
Yes, the upbeat reaction to Fukushima outside Japan has been disturbing. The fact that it would be hard to equal Chernobyl doesn't diminish the reality that this is easily the second-worst disaster in the history of nuclear power. People have been killed, and the entire complex is effectively trashed. One reactor at TMI took 14 years and a billion dollars to clean up; Fukushima is going to be a nightmare to set right even if things don't get worse.
Of course, this is assuming that things aren't worse than the official statements let on. The sordid history of the Japanese nuclear industry, including falsification of safety records at Fukushima, doesn't inspire confidence. Japanese nuclear officials are notoriously slippery in front of the press, and the lack of reliable information from Fukushima has been very frustrating. No one really knows what's going on there, and every time the officials claim to have it under control another building explodes.
Well put. This is a highly chaotic situation unfolding as we speak. If any of that fuel catches fire, those of us sitting on our couches in silicon valley may very get a nice early spring gift from jet stream.
Even if AT THIS POINT the chances of such a fire are <1% (which quite frankly seems optimistic) we should be very very concerned...
Software engineers especially, but engineers in general, have a tendency to love complex machines. But engineers of all kinds SHOULD know best: that there are ALWAYS bugs, and where you least expect them.
We ought to put aside the politics here: whether you like nuclear power or you don't: we've all been very much dependent on it, and benefited from it greatly. It's impact on life is different, but not clearly better or worse than other sources.
Let's hope the engineers on the ground in Japan are getting very very creative.
I think a big part of it is we've had it drilled into us that fears of nuclear meltdowns are irrational. That people are just misinformed & scared of something they can't see or possibly understand. And we like to think we're smarter than the general population.
But clearly no one knows how bad this situation is going to get.
Alternative explanation: Being a pessimist is not productive. Woo-hoo, you were something in the ballpark of right. Is the world better because of it? If you look at every situation and assume the worst, you'll be right sometimes, but you'll never accomplish anything.
I'll step in and defend nuclear power. This crisis looks horrible and might even lead to multiple core melts with containment breach. But let's not forget this was a horrible natural disaster first. We engineers never said a meltdown could never happen but that we have done everything possible to minimize the risk. I can predict that the amount of lives lost and property damaged due to this accident will pale when compared to other forms of energy including coal, gas or oil when things go wrong -- a price we pay every single day and is so common it hardly registers as news. What was cost of the BP oil spill? Read your local news for local gas explosions, oil spills, injured workers, etc. People are killed in the coal industry every single year. These are such every day occurrences they don't even register unless many people are killed or it involves barrels of oil. This accident is like a plane crash that draws attention to the horrors of flight when things go wrong -- but we still fly and flying is orders of magnitude safer then getting in your car.
All energy sources have risks and I believe that nuclear can be safe and reliable and better than any of the alternatives. In the end we will build nuclear power plants because there is no other large scale source of energy that can power an industrial civilization. (If you think so-called green energy and solar power can save us you need to learn some math. You are an environmentalist dupe). Need I remind all the ambitious hackers on HN that computers and the internet do not run on pixie dust -- it is running on oil, gas, coal and, yes, nuclear power right now. We know that at some point the oil will run out or become too expensive to mine. At that point its nuclear or turn off the lights and the drastic drop in living standards that implies.
This accident will teach us a lot about how to design and build reactors and nuclear power stations and maybe will delay the construction of those new plants which would be the real tragedy of this accident. We need to start building them now.
It's instructive that we've already engineered ways of preventing the problems TEPCO is experiencing at their Fukushima. Many newer reactor designs have a passive residual heat removal system that removes decay heat even without electrical power to run cooling pumps.
Good answer. I actually don't know the figures, but I know what sort of argument it would take to convince me: some numbers showing that nuclear power production takes a substantially higher toll on life and health than other forms of energy production, measured by kWh. This number determines whether producing the same amount of power by other means is going to save people, or kill people. (Yes, it's not out of the question that environmentalist activism kills people. Good intentions don't protect from bad consequences.) Maybe the people who advocate stopping nuclear power should cite their acceptable figures of death toll per kWh produced, and then we can compare with oil and coal. Emotional arguments only get us so far.
As regarding sustainable energy, here's my favorite book on the subject: http://withouthotair.com . It takes the approach I like: "let's just sit down and calculate".
From the Japanese Prime Minister and Chief Cabinet Secretary. My source is NHK World (Japan News):
People up to 30km from Dai-ichi (number-1) plant are being asked to remain indoors. ALL people within 20km of PLANT 1 are being asked to evacuate.
The Japanese Govt. have asked the Japanese people to act calmly. (My comment: Watch the stock market now.)
Here we go (information for PLANT 1 - Dai-ichi):
Number 4 reactor: is on fire. There has been a hydrogen explosion there. There was an implosion of the building structure. Radiation is being released into the environment. Note reactor 4 was not in operation, but the fire has caused spent fuel to heat up generating hydrogen.
Number 2 reactor: there was a blast 30 minutes after number 4's explosion. A hole/crack (trans?) has been observed in the reactor. Radioactive material has been released to the environment.
At 10:22am between reactor 2 and 3, 30milliSievert and at reactor 4, 100 milliSievert. At reactor 3 the reading was 400 MILLI Sieverts. Note MILLI, not micro.
They believe the fire at reactor number 4 is likely the main cause of the dramatic increase in radiation.
The roof of a containment facility for spent fuel has also been damaged. It is possible that a leak exists there too.
> A hole has been observed in the reactor. Radioactive
> material has been released to the environment.
I was just watching the press conference, and I could have sworn they said that the hole was in the reactor housing, and that little to no radiation was being released from this reactor. I was only paying half-attention though.
I keep hearing about seawater being pumped into the reactor chamber but apparently the chamber is still very hot. Where is all this seawater going? Steam? How big is this chamber?
EDIT: Also I've heard of at least two explosions. Does this mean that containment vessels are compromised? What exactly exploded?
The water heats up, building pressure, and then they vent some steam to try and lower the pressure (and then, obviously, have to re-add water). The explosions happen because the steam separates into Hydrogen & Oxygen due to a reaction, and once outside that is an explosive mix.
The chamber is pretty large, several meters deep around the core.
The explosions are as a result of the release of the hydrogen/oxygen mix - which does not take much to catch - but they occurred outside the pressure vessel. Such a situations is technically planned for, the building structure "fails outward" allowing the blast out and away from the pressure containment. It is relatively unlikely to damage the integrity of the vessel in such a situation; they are very very strong pieces of kit (at three mile island the explosion took place inside the vessel and I believe it did not compromise its integrity).
At this stage is somewhat unclear but it appears that the third explosion has damaged one of the pressure vessels. However the technical explanations I am seeing are stating that it hasn't compromised the integrity of the containment; instead it appears to be saying that parts of the mechanism inside the containment are damaged (in this case the "torus" which is used as an emergency pressure relief system).
This is actually, though, a significant problem, if true, because it could affect what happens if it finally does meltdown (as I mention in another comment, my working knowledge of this form of reactor is incomplete, but IIRC the torus also forms part of the final emergency response to a meltdown).
Bottom line is; at this stage we know there have been 3 hydrogen explosions at 3 of the units, and one fire at another of the reactors. But it is still unclear the level of damage and risk with each unit - TEPCO (and indeed Japanese companies in general) tend to play down or not discuss details and risk publicly. Take this fire; no one really picked it up until it was out - at which point TEPCO appear to have started mentioning it.
If I had to lay a claim I suspect that reactor 2 at this stage will probably meltdown; loss of the torus is significant enough that it raises the risk of what they are currently doing (i.e. trying to cool the core).
Whilst I can't claim to know the answer to your question, my guess/understanding is that it goes around the circuit and condenses in the heat exchange. It is then recycled.
Some steam is lost when they vent hydrogen, presumably.
Regarding the explosions, according to http://mitnse.com/, the Fukushima explosion occured in the ventilation system, outside of all containment vessels.
Just a note - all radiation levels reported from around the plant are measured in milli(m)/micro(u)-sieverts(Sv) per hour. For comparison, the worldwide average background radiation level is approx. 0.274 uSv/h, and the usa recommended continuous occupational limit is 5.71 uSv/h. For example, the highest level I've seen reported is 400 mSv/h, or 70000x the recommended limit. Info from wikipedia.
I've seen lots of things reported, but I'm always leery of things that have gone through two or three languages to get to us. We've all played that translation party where things get translated into gibberish. I'm going to have to take it with a grain of salt when people get their news from the French embassy (which, last I knew, was not known for nuclear expertise, but feel free to prove me wrong).
Kyodo News (http://english.kyodonews.jp/) are reporting that radiation levels in Chiba are twice to 4 times normal level and 33 times normal level in Utsunomiya, Tochigi.
Japan's warning that all people within 30 kilometers from Fukushima should stay indoors and that the radioactive winds may reach Tokyo in as little as 8 hours
[+] [-] jedsmith|15 years ago|reply
Conclusions at any stage of this crisis have been premature, but HN seems to want a heavy dose of finality to a crisis that isn't even over yet. Apparently people don't want it to be a big deal, but it's slowly turning into a big deal. It just is. Instead of big essays and conclusions about how the powers-that-be have it under control complete with inaccurate depictions of how a reactor works, why don't we focus on facts?
With that in mind, we do not know how bad it is. Anyone who says they do is lying to you. It isn't over, and it is a basic fact of logic that we will not be able to reflect on how bad this is or was until it is over.
At the risk of a neener-neener I told you so, I presented some of this viewpoint[2] on the self-aggrandizing risk management Ph.D.'s everything's fine piece, but my viewpoint was drowned out by people wanting to rush to a conclusion so they can put the crisis out of sight and out of mind.
[1]: http://edition.cnn.com/2003/WORLD/asiapcf/east/06/17/tokyo.s...
[2]: http://news.ycombinator.com/item?id=2319305
[+] [-] forensic|15 years ago|reply
It's inconceivable (cue sound clip from Princess Bride) to most of us that extremely extensive and effective contingency plans are not in place.
The nuclear risk is obvious, and so any nuclear construction's main emphasis must be on handling all possible contingencies... right?
If Fukushima does end up being a "Big Deal" that is going to forcibly shift the world view of many many engineers and hackers. It will represent a piece of data that is fundamentally at odds with our view of the world.
The facts will eventually win out, but for the short term, it is necessary that we go through these cycles of disbelief and then shock. Because that's just reality.
I will be shocked if Fukushima causes serious harm to humans because until now it has been inconceivable to me that people making nuke plants could possibly underestimate the risks. If my inaccurate beliefs are shattered by the harsh reality of nuclear related deaths then... that's just how it will have to be. I'll have to eat my hat. I'm not looking forward to it.
In the meantime I have to go with what I know. Which is that this should not be an issue that threatens human life.
[+] [-] mechanical_fish|15 years ago|reply
Because we don't have any actionable ones?
But, okay, as you wish. I have the crisis firmly in mind now. I will not "rush to believe that everything is fine" or anything.
So.
Do you have any advice about what action I should take next? I live twelve time zones away, am a citizen of a different country, and have only a passing acquaintance with nuclear engineering.
I can't accomplish anything useful by panicking. I can't change building codes from N years ago, I couldn't prosecute anyone in Japan for negligence even if I had any evidence of same (which I do not), I can't dictate to Japanese industry even if I knew what to do (which I obviously don't), I can't run the Japanese government, I can't even vote in Japan. Neither I nor anything else we know can stop radioactive elements from decaying, and I can't unwind time and stop the earthquake.
I suppose I can raise my blood pressure, and raise the blood pressure of everyone else I know, and we might even achieve mass hysteria. Is that really a good idea? Why? Like every citizen of the USA, I happen to have some experience with mass hysteria. It didn't turn out well in 2001. I'm not anxious to see more of it.
What would you like me to do, instead of waiting for events to unfold, staying away from certain portions of the Japanese coast, hoping that various Japanese nuclear engineers have done their duty well, and meanwhile focusing on other things?
[+] [-] icarus_drowning|15 years ago|reply
I applaud your more measured approach, but I must say that, as someone who has read most of the stories and comments regarding this topic that have hit the front page, I do feel that you are decidedly in the minority. There are plenty of people rushing to call this a horrendous disaster, who are privy to the same limited information, and who are likewise doing very little to contribute to the discussion.
[+] [-] pyre|15 years ago|reply
I think that the reality probably boils down to:
[+] [-] guelo|15 years ago|reply
[+] [-] tres|15 years ago|reply
I keep on thinking of Akira Kurosawa's "Dreams..." (One of the segments deals with just this kind of scenario. The protagonist finds himself in hell after a nuclear disaster.) A horror like this has been in the cultural subconscious of Japan for decades. They always knew that there was a possibility of something like this, but they chose to gamble against it happening.
They didn't do it because they were foolish, or naive. They did their best to avert that disaster. The people had faith in the talent and skills of those engineers responsible.
It's our nature to want to see the good... even in a horror like this. (Especially a bunch of people who are willing to risk everything to start a business.)
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] pessimist|15 years ago|reply
1. In reactor 4 spent fuel rods are burning and radioactivity is being freely vented in to the air. NONE of the optimistic reports suggested this possibility but I see a prophetic article at http://www.nytimes.com/2011/03/15/world/asia/15fuel.html.
2. Reactor 2 has had an explosion that has damaged the core containment structure - something we were assured would not happen.
Why were engineers so optimistic, while the ground reality is so much worse? Probably the complexity of the system escapes us and look at small parts of the issue and assume they are under control. In reality many things are interacting and the combination can overwhelm defences. For eg. as water is being routed to reactors 1, 2 and 3 to prevent meltdowns, the spent fuel rods are overheating.
Hubris strikes again.
[+] [-] gamble|15 years ago|reply
Of course, this is assuming that things aren't worse than the official statements let on. The sordid history of the Japanese nuclear industry, including falsification of safety records at Fukushima, doesn't inspire confidence. Japanese nuclear officials are notoriously slippery in front of the press, and the lack of reliable information from Fukushima has been very frustrating. No one really knows what's going on there, and every time the officials claim to have it under control another building explodes.
[+] [-] redwood|15 years ago|reply
Even if AT THIS POINT the chances of such a fire are <1% (which quite frankly seems optimistic) we should be very very concerned...
Software engineers especially, but engineers in general, have a tendency to love complex machines. But engineers of all kinds SHOULD know best: that there are ALWAYS bugs, and where you least expect them.
We ought to put aside the politics here: whether you like nuclear power or you don't: we've all been very much dependent on it, and benefited from it greatly. It's impact on life is different, but not clearly better or worse than other sources.
Let's hope the engineers on the ground in Japan are getting very very creative.
[+] [-] hartror|15 years ago|reply
2. The hydrogen explosion on 2 may have damaged containment.
[+] [-] btucker|15 years ago|reply
But clearly no one knows how bad this situation is going to get.
[+] [-] sp332|15 years ago|reply
[+] [-] pessimist|15 years ago|reply
[+] [-] gnosis|15 years ago|reply
There are way too many people on here who've been drinking too much of the radioactive koolaid doled out by the nuclear industry.
The general consensus here tends to be that nuclear power is wonderful and amazingly safe.
Well, we're seeing them being proven wrong yet again. How much more proof are they going to need? How many more nuclear disasters is it going to take?
[+] [-] chc|15 years ago|reply
[+] [-] dmfdmf|15 years ago|reply
All energy sources have risks and I believe that nuclear can be safe and reliable and better than any of the alternatives. In the end we will build nuclear power plants because there is no other large scale source of energy that can power an industrial civilization. (If you think so-called green energy and solar power can save us you need to learn some math. You are an environmentalist dupe). Need I remind all the ambitious hackers on HN that computers and the internet do not run on pixie dust -- it is running on oil, gas, coal and, yes, nuclear power right now. We know that at some point the oil will run out or become too expensive to mine. At that point its nuclear or turn off the lights and the drastic drop in living standards that implies.
This accident will teach us a lot about how to design and build reactors and nuclear power stations and maybe will delay the construction of those new plants which would be the real tragedy of this accident. We need to start building them now.
[+] [-] mmaro|15 years ago|reply
It's instructive that we've already engineered ways of preventing the problems TEPCO is experiencing at their Fukushima. Many newer reactor designs have a passive residual heat removal system that removes decay heat even without electrical power to run cooling pumps.
http://www.ap1000.westinghousenuclear.com/ap1000_psrs_pccs.h...
[+] [-] cousin_it|15 years ago|reply
As regarding sustainable energy, here's my favorite book on the subject: http://withouthotair.com . It takes the approach I like: "let's just sit down and calculate".
[+] [-] piguy314|15 years ago|reply
[deleted]
[+] [-] brazzy|15 years ago|reply
You need to learn some reality. You are a nuclear lobby dupe.
[+] [-] wbhart|15 years ago|reply
From the Japanese Prime Minister and Chief Cabinet Secretary. My source is NHK World (Japan News):
People up to 30km from Dai-ichi (number-1) plant are being asked to remain indoors. ALL people within 20km of PLANT 1 are being asked to evacuate.
The Japanese Govt. have asked the Japanese people to act calmly. (My comment: Watch the stock market now.)
Here we go (information for PLANT 1 - Dai-ichi):
Number 4 reactor: is on fire. There has been a hydrogen explosion there. There was an implosion of the building structure. Radiation is being released into the environment. Note reactor 4 was not in operation, but the fire has caused spent fuel to heat up generating hydrogen.
Number 2 reactor: there was a blast 30 minutes after number 4's explosion. A hole/crack (trans?) has been observed in the reactor. Radioactive material has been released to the environment.
At 10:22am between reactor 2 and 3, 30milliSievert and at reactor 4, 100 milliSievert. At reactor 3 the reading was 400 MILLI Sieverts. Note MILLI, not micro.
They believe the fire at reactor number 4 is likely the main cause of the dramatic increase in radiation.
The roof of a containment facility for spent fuel has also been damaged. It is possible that a leak exists there too.
[+] [-] pyre|15 years ago|reply
[+] [-] radicaldreamer|15 years ago|reply
Previous measurements were in micro sieverts.
Source: https://twitter.com/#!/timeouttokyo/status/47480888463859712
[+] [-] burke|15 years ago|reply
[+] [-] jfoley|15 years ago|reply
[+] [-] ronnier|15 years ago|reply
http://imgur.com/L8WKW?full
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] ashbrahma|15 years ago|reply
http://news.ycombinator.com/item?id=2318980
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] dmm|15 years ago|reply
I keep hearing about seawater being pumped into the reactor chamber but apparently the chamber is still very hot. Where is all this seawater going? Steam? How big is this chamber?
EDIT: Also I've heard of at least two explosions. Does this mean that containment vessels are compromised? What exactly exploded?
[+] [-] ErrantX|15 years ago|reply
The chamber is pretty large, several meters deep around the core.
The explosions are as a result of the release of the hydrogen/oxygen mix - which does not take much to catch - but they occurred outside the pressure vessel. Such a situations is technically planned for, the building structure "fails outward" allowing the blast out and away from the pressure containment. It is relatively unlikely to damage the integrity of the vessel in such a situation; they are very very strong pieces of kit (at three mile island the explosion took place inside the vessel and I believe it did not compromise its integrity).
At this stage is somewhat unclear but it appears that the third explosion has damaged one of the pressure vessels. However the technical explanations I am seeing are stating that it hasn't compromised the integrity of the containment; instead it appears to be saying that parts of the mechanism inside the containment are damaged (in this case the "torus" which is used as an emergency pressure relief system).
This is actually, though, a significant problem, if true, because it could affect what happens if it finally does meltdown (as I mention in another comment, my working knowledge of this form of reactor is incomplete, but IIRC the torus also forms part of the final emergency response to a meltdown).
Bottom line is; at this stage we know there have been 3 hydrogen explosions at 3 of the units, and one fire at another of the reactors. But it is still unclear the level of damage and risk with each unit - TEPCO (and indeed Japanese companies in general) tend to play down or not discuss details and risk publicly. Take this fire; no one really picked it up until it was out - at which point TEPCO appear to have started mentioning it.
If I had to lay a claim I suspect that reactor 2 at this stage will probably meltdown; loss of the torus is significant enough that it raises the risk of what they are currently doing (i.e. trying to cool the core).
[+] [-] wbhart|15 years ago|reply
Some steam is lost when they vent hydrogen, presumably.
[+] [-] dmm|15 years ago|reply
[+] [-] cdellin|15 years ago|reply
[+] [-] Natsu|15 years ago|reply
"As of 0:30 pm, the measured value of radiation dose near MP6 was 4μSv/h. The increase of the radiation dose cannot be confirmed at this time."
http://www.tepco.co.jp/en/press/corp-com/release/11031405-e....
I've seen lots of things reported, but I'm always leery of things that have gone through two or three languages to get to us. We've all played that translation party where things get translated into gibberish. I'm going to have to take it with a grain of salt when people get their news from the French embassy (which, last I knew, was not known for nuclear expertise, but feel free to prove me wrong).
[+] [-] gnosis|15 years ago|reply
...if the fuel pools are not cooled, they will melt down, in which case we’re going to have Chernobyl on steroids."
http://www.democracynow.org/2011/3/14/japan_facing_biggest_c...
[+] [-] Element_|15 years ago|reply
Rough translation of the prime ministers speech on reddit: http://www.reddit.com/r/worldnews/comments/g3zel/breaking_ex...
[+] [-] ronnier|15 years ago|reply
http://www3.nhk.or.jp/nhkworld/r/movie/
[+] [-] squidsoup|15 years ago|reply
[+] [-] chailatte|15 years ago|reply
Nikkei Flash Crash - Futures Plummet 16%
http://www.zerohedge.com/article/nikkei-flash-crash-futures-...
[+] [-] unknown|15 years ago|reply
[deleted]
[+] [-] hartror|15 years ago|reply