I am astounded by all the wild misinformation bandied about here and in other political sites. Lots of people seem intent on making political points without actually understanding the technical facts. In this diary, I'll try to present a simple explanation of what's happening, without the hyperbole and innuendo that some people here on dKos can't seem to resist. I will clearly differentiate known facts from my own interpretations.
First, some credentials: I hold an MS in physics. My thesis work was on visual binary stars, but for two years afterwards I taught energy-related issues. As part of this I suffered through indoctrination by a group of pro-nuclear activists at Oak Ridge Associated Universities in Oak Ridge, Tennessee, where you could buy "Atom Burgers" at the local food joints. Fortunately, I was employed by and based at the University of California at Davis, where the local food joints sold "Solar Salads". By temperament, I was more closely aligned to the Davis weltangschaung, and nearly got thrown out of ORAU's training program for my lack of enthusiasm for nuclear. However, I also have a strong sense of intellectual integrity, and I've long felt that nuclear power is sorely misapprehended by the public. Nuclear power is the fourth-worst source of energy available to us, after coal, oil, and natural gas. I'm all for a gung-ho approach to renewables, but I'm not naive enough to believe that they can solve our problems in the next few decades. MAYBE in fifty years... my crystal ball doesn't see that far ahead. Anyway, on to the subject:
When the biggest earthquake in Japanese history hit on Friday, all the reactors in northern Japan immediately and automatically shut down. The reactor cores continued to generate perhaps 50 megawatts of "decay heat", slowing falling in power output. That's a hell of a lot of heat, so the cooling systems have to continue pumping cooling water through the reactor cores to keep them from overheating and melting down. The problem is, these reactors much rely on external power to feed those water pumps, and the earthquake knocked out power lines all over the area, so the water pumps had no power. No problem! They've got a backup generator on site that automatically fires up and easily generates enough power to keep the pumps turning and the water flowing.
But 20 minutes later the biggest tsunami in Japanese history swept over the power plants. This by itself was no problem: the buildings were strong enough to withstand an 9.0 magnitude earthquake, so the tsunami didn't damage them significantly. But the tsunami DID take out the backup generators. Oops! Well, they still had backup generators for the backup generators -- but those were knocked out by the tsunami, too.
So far, Lady Luck had been rolling snake-eyes for the nuclear plants, but they still had yet ANOTHER backup -- emergency batteries that can keep the pumps running for twelve hours. These kicked in and kept things in line for twelve hours. That SHOULD have been plenty of time to bring in emergency repair crews to fix the emergency generators but Lady Luck rolled more snake-eyes: the repair crews couldn't get the generators running because they were still swamped in water which they couldn't pump out fast enough -- and lots of ancillary electrical systems were heavily damaged as well. They'd need a major repair group with lots of time and equipment to get all that stuff operational again.
But the Japanese had yet another card up their sleeves: bring in emergency generators on trucks. Lady Luck slowed them down with a variety of damaged roads, but they got the trucks in place -- only to discover some incompatibility between the truck generators and the pumps. I don't know exactly what the incompatibility was -- somebody suggested that the plugs on the generators didn't match the sockets on the pumps, but I find that a rather simplistic explanation. It might have been a voltage mismatch or perhaps a switching problem (You don't just throw a switch when you're dealing with that kind of power -- the arc will blow the switch. You need a very special kind of switch to hook these things up, because the startup currents are strong enough to melt just about any cable in the universe.) It might have been any number of problems. My personal guess is that the power plant was designed for emergency generator systems as they existed when the plant was built, and sometime during the decades since design and earthquake, something changed in a small but crucial way to make the current generators incompatible with the pumps.
That was where things stood Saturday night when I went to bed. I was worried that, if they didn't get water into those plants soon, they'd suffer a full meltdown. Not that a full meltdown was particularly dangerous -- we had something close to a full meltdown at Three Mile Island thirty years ago and the primary containment structure performed exactly as designed and never released any serious amount of radioactivity. The Japanese containment buildings are built to be even stronger than the TMI containment structure. On the other hand, they were not built to withstand an earthquake 7 times more powerful than the most powerful earthquake in all of Japanese history. Perhaps they had suffered some structural problem that would leak radioactivity. So, yes, I was concerned, but not alarmed. My guess as of Saturday night at bedtime was that the reactors would be a total loss and there would be minor amounts of radioactivity released, but nothing terribly dangerous, and certainly nothing catastrophic.
When I read on Sunday morning that they were pumping seawater into the systems using fire engines, I knew that my guess was confirmed. The seawater would ruin the systems so that they'd never be usable again. But it also insured that the systems wouldn't melt down in any serious way. Indeed, I surmise that it was the discovery of cesium in the radioactive steam that forced their hands. Cesium can only get into the steam if the cladding on some of the fuel rods has failed, releasing nuclear fuel into the water. That means that meltdown has just begun. When they discovered the cesium, they knew that the reactor was a total loss, so there was nothing left to save. Pump in the seawater to prevent any further melting, which in turn would only make the cleanup more expensive.
At that point, I was willing to tell myself "It's over" -- except for the fact that there were still a few wild cards left in Lady Luck's deck. There could be a major aftershock to the earthquake, leading to another tsunami that might swamp the fire trucks pumping seawater. Were the fire truck pumps designed to operate for a week continuously? What if they got a big pump running and the pressure surge blew open one of the possibly weakened pipes? All of these problems can be anticipated and prepared for, but when people have been running for three days on caffeine, they make mistakes. The situation was stable, but still critical.
By this morning, the only news was the second hydrogen explosion. No big deal, I thought, although the public and press read the two words "explosion" and "nuclear" and went into full-press eyeball-bulging panic mode.
From this point forward, I predict that, barring some real creativity on Lady Luck's part, the situation will grow boring and the press will move on to other gory stories -- after all, they sell cheap thrills, not information. We'll have heartwarming stories of miraculous rescues, tragic stories of mountains of dead bodies, thrilling stories of close brushes with death, and there will never be any stories along the lines of "everything's safe at the nuclear power plants" -- although there will be plenty of "what if" stories and blood-curdling stories of how many millions might have died, but didn't.
Now to address some of the most egregious misinformation out there:
First, the usual reminder that a nuclear plant simply cannot undergo a nuclear explosion. No way. No how. Impossible. Anybody who tells you otherwise is a flat-out liar.
Second, there's no way this could be another Chernobyl. Chernobyl was a graphite-moderated reactor without containment. This is truly an idiotic design; it's like building a car engine using TNT for the engine block. When the thing caught fire, my immediate reaction was, "Well, it finally happened." We in the USA did manage to come up with something about half as stupid: the LMFBR (Liquid Metal Fast Breeder Reactor) which could, with extremely generous theoretical assumptions, actually undergo something like a small nuclear explosion (which was termed a "rapid disassembly" -- but that's an entirely different, and quite entertaining story). What made the LMFBR so stunningly stupid was its use of liquid sodium as a coolant. At room temperature, solid pure sodium reacts energetically with water vapor in the air -- in layman's terms, it burns. In grad school, it was fun to slice off bits of pure lithium (a close relative to sodium) and toss them into the toilet to watch them fizzle and pop in the water. Young chemists make stink bombs, young physicists play with lithium.
Anyway, the LMFBR was wisely shut down by Jimmy Carter, much to my relief. But there are STILL people in Oak Ridge who swear that it would have been just fine. Right.
Onto the third blatant falsehood: meltdown=catastrophe. Sheesh, we disproved that at TMI, where we had a large-scale meltdown. Thirty years later, numerous studies have shown absolutely no undesirable population health effects. They did find a decrease in miscarriage rates, but I don't think it's fair to claim that TMI is the source of that decrease. The only study that even suggested anything injurious was a calculation that some of traffic injuries during that week were statistically like to have been due to the increase in traffic caused by the undue panic surrounding the plant. FDR really was right: the only thing we had to fear then was fear itself.
It is already a near-certainty that two of the reactors have undergone minor meltdowns. A third might well go the same way. Those meltdowns may prove to be worse than minor; they might even prove to have been major. But none of these things mean that any of that radioactivity will get out, because the last card up the sleeve of the Japanese designers is an ace: the containment structure. Those things are really, really thick, and really, really strong. They can take a direct hit from a fully loaded, fully fueled Boeing 747 and not be compromised.
There's lots more misinformation out there; I have only scratched the surface of the craziness. I swear, the anti-nuclear enthusiasts are almost as bad as the tea-partiers when it comes to truth. Not AS bad, mind you -- I can't imagine anybody being as fast and lose with the truth as the tea partiers.
Some general advice for evaluating the tsunami of rumor inundating the web about this situation:
1. Don't trust anybody. Not me, not any other commentator on dKos, and CERTAINLY not any industry source. Accept only outright, objectively verifiable statements of fact, statements like "We turned on the pumps" or even "we measured this much radiation". Those things can and will be checked by the Japanese government, and you can be sure that they'll pounce on the opportunity to finger a scapegoat if they can. And no, you should also refuse to trust anything coming from any already-established anti-nuclear group. They have axes to grind, too.
2. You can trust the American National Academy of Sciences. They're zealous to protect their reputation for probity, and they're extremely cautious, usually declaring "More research is necessary" -- but when they DO make a statement, you can usually bet your bottom dollar on it.
3. Follow debates such as the one this will trigger (unfortunately, I doubt that I'll have enough time to respond to all the comments if this post gets recc'd -- but it probably won't get recc'd, so I expect I'll be safe.) Read both sides carefully and skeptically. Apply all the standard critical methods: who backs up their claims with some sort of facts? Who makes accusations rather than lines of reasoning? Who seems emotionally involved? Who seems to know what they're talking about? The best way to discover the truth is by seeing both the light and shadow. Good luck.
Updated by Erasmussimo at Tue Mar 15, 2011, 01:38:15 PM
Update, Thursday, 9:35 PDT
I have now had the opportunity to go through a goodly variety of sources. Unfortunately, I still can't get access to detailed technical information -- direct readings and such. I know that information is available somewhere and I'm working some contacts in the nuclear industry to find out where I can get hard numbers. I have reached a point of diminishing returns in that most of the information I find in any given article is merely a repeat of information I have earlier found, so I believe that, while the information I have collected is still unsatisfactory, it is at least adequate for some conclusions. I shall present that information in a format you probably haven't seen: reactor by reactor, the plant as a whole, the immediate region, and Tokyo. I warn you that all these statements (except where noted) are interpretations on my part, based in many cases on what has NOT been said.
Unit #1: situation is stable but delicate. No significant incidents. They continue to "bleed and feed" -- release steam as pressure builds up, thereby releasing small amounts of radioactivity, but preventing further damage. The reactor is a total loss. However, the reactor core continues to cool naturally, and so the danger is steadily receding. Barring some new radical development, we can put this one on the back burner of our concerns.
Unit #2. This generated a considerable amount of excitement yesterday when what was probably a hydrogen explosion localized to the lower part of the containment structure appears to have cracked the plumbing down there, releasing water from inside the plumbing to the bottom of the containment structure. The water inside the plumbing is highly radioactive, but by venting steam (which is much less radioactive), the operators were able to minimize the danger. Now that radioactive water is loose in the containment structure, the opportunities for release of radioactivity have increased. There was a burst of intense radiation at the same time, but it's difficult to say whether that radiation came from Unit #2 or Unit #4 -- see below. At this time, Unit #2 does not appear to be releasing dangerous amounts of radiation -- but I don't have individual reactor radioactivity release readings, only general site readings. All in all, Unit #2 is still in critical condition, but at this time the situation appears stable and improving. I wouldn't put it on the back burner of our concerns, but things aren't getting worse there.
Unit #3. This was the big scare Saturday and Sunday, but nothing alarming has happened since then. Like Unit #1, it is a total loss, and they're continuing "bleed and feed" with no difficulties. Like Unit #1, the core power generation is naturally diminishing with time. This one goes on the back burner for the time being.
Unit #4. The reactor itself was shut down for maintenance prior to the earthquake, so its core is in no trouble, but there was a big problem with the spent fuel pool. My hunch is that, with all the other problems they were facing, the operators gave little attention to Unit #4, and the water levels in the spent fuel pool fell far enough to expose the tops of the spent fuel assemblies, which subsequently overheated and caught fire. This was most probably the source of the intense burst of radioactivity recorded on site. They were able to quench the fire, but I don't know how they did it, so I can't say whether the situation there is stable; current reports say that the water is boiling, which suggests that their solution is a batch process rather than a continuous feed of water. They are trying to get helicopters in place to dump water into the spent fuel pools. Fortunately, this should be a straightforward process; if they use a regular firefighting helicopter equipped with a bucket, they can ferry water from any nearby fresh water source. Two problems: they don't want to use seawater because the salt will further degrade the cladding in the fuel assemblies, increasing the risk of radioactive release; and they don't want to simply dump the water into the pools, because that will splash radioactive water around, generating more mess. So they'll have to proceed delicately. Moreover, the propwash from the helicopter blades might scatter some stuff, making some more mess.
Yesterday I had opined that the spent fuel pools had some sort of covering. I now want to eat some crow over that; further research has indicated that whatever covering they have is likely a retractible plastic sheet of some sort, which would not have withstood falling debris of any weight. OTOH, it might be that this plastic covering was the main fuel for the fire, which would certainly explain why the fire was so short-lived.
All in all, I'd keep the Unit #4 spent fuel pools on the front burner of concerns.
Units #5 and #6. These units are in pretty good shape. The reactor cores shut down properly and are getting plenty of feedwater to keep them cool. However, the feedwater to the spent fuel pools has for some reason been curtailed -- at the moment, the best guess I saw was that there was an electrical problem. The temperature in the pools has risen from the normal 40ºC (about 105ºF) to about 80ºC (175ºF). So long as the temperature doesn't reach the boiling point, there's little cause for concern, but their safety margin has been reduced and there is definitely a problem here.
The plant as a whole: there was a huge spike of radioactivity yesterday, probably because of the fire at the spent fuel pool in Unit #4, but the explosion in Unit #2 probably contributed a small amount to that spike. The peak reading was about 12,000 msV/hr, which is very, very high -- the danger level is 100 msV/hr. However, this peak was short-lived; six hours later it had dropped to 500 msV/hour and was still falling. That's why they evacuated everybody but a skeleton crew of volunteers whom they're rotating out of there quickly. They'll now implement a rotation system, bringing in fresh workers to work for a short time and then get out before they get enough of a dose to be dangerous (I did something like that once at a cyclotron, and it never had any long term effects on me... on me... on me... where was I?)
The site radiation levels continue to fall but the most recent readings I have are about 12 hours old.
The general neighborhood has been evacuated and they're keeping everybody a goodly distance away, but this is more precautionary in nature; my guess is that people 10 or 20 km away are at little risk except for things like that huge burst of radioactivity. They're keeping everybody away just in case there's another huge burst of radioactivity.
Tokyo: the readings there are 0.6 msV/hour, which is ten times greater than normal and would constitute a population health hazard if it were to continue for, say, a few months, but for short term considerations is of no consequence.
After considering all this information, I have come to the conclusion that it is incumbent upon me to masticate a few crow feathers: I failed to take into account the likelihood that the spent fuel pool at Unit #4 would suffer a fire, because Unit #4 had been long shut down and should not have been any problem at all. I, like everybody else, was fixated upon the reactors that were actually in trouble. The explosion at Unit #2 was the worst of the hydrogen explosions, and its focal point low in the containment structure came as a shock -- hydrogen explosions are to be expected high up, because hydrogen rises. The plumbing is down low, so this explosion was more destructive. While there was some leakage of radiation, it does not appear that any major damage was done to the primary containment structure; my hunch is that we have a broken seal somewhere that's venting some radioactive gases.
Yesterday I was asked to present an overall assessment of the danger level on a 1 to 7 seven scale. I interpreted this to mean an assessment of the risk of non-worker casualties. Yesterday morning I would have put that risk at 1±1: essentially no members of the public suffering injury from radiation. The new explosion and the fire caused me to adjust my estimate upwards to 4±3, which was basically a statement that I couldn't draw any conclusions yet. My current assessment is down to 2±1: to be more explicit, I suspect that, over the next 30 years, we'll get probably a dozen or two deaths from the radiation that has been and will be released by this accident; possibly as many as a hundred.
This brings me to a different topic. Last night, while reading the newspaper coverage of the situation, I became rather angry. The situation in Japan is that something like 10,000 people have died from the earthquake and tsunami; vast devastation has been wrought by these events, half a million people are homeless, and people in the affected areas are scrounging for food, warmth, and potable water. And yet the damn newspaper can only talk about the nuclear reactors, which are very unlikely to generate even one-hundredth as much human suffering as the earthquake+tsunami. I am also irked by the callous political opportunism of some anti-nuclear people, who would rather spend their time overhyping the reactor troubles than concentrate on the real suffering going on elsewhere in Japan. In most wars, there are at least ten times as many civilian casualties as combatant casualties, but all we ever see in the media are stories about the soldiers. In the Israeli-Palestinian conflict, we see plenty of stories about suicide bombers, rocket attacks, and aircraft bombardments, but we never read about the steady line of hearses carrying old people who died of some stupid ailment because they couldn't get through the roadblocks fast enough to reach the hospital in time, or little kids who died of a fever for the same reason. People don't want information that matters, they want cheap thrills. It truly disgusts me.
But enough ranting for the moment. I'll respond to comments with facts if and when I have them.
Updated by Erasmussimo at Tue Mar 15, 2011 at 02:06 PM PDT
Here's a great example of how badly the news media are misleading the public. ABC news just today published a news story with this screaming headline:
Japan nuke crisis 'worse than Three Mile Island'
but in the interior of the story, they quote an IAEA official as follows:
"Nevertheless, the damage "is estimated to be less than 5 per cent of the fuel", he said."
TMI suffered almost 100% fuel melt. ABC must believe that 5% > 100%.
Updated by Erasmussimo at Tue Mar 15, 2011 at 02:26 PM PDT
I just discovered an excellent source of hard information: Wikipedia! I had always thought that their stuff was updated only occasionally, but the data they have there is only a few hours old! Here's the link, which I can't figure out how to embed properly in an update editor:
http://en.wikipedia.org/...
The Reactor Status summary table (about halfway down) puts it all down cleanly and clearly. The local radiation level is an astoundingly low 0.5 mSv/hour -- lower than they were in Tokyo a few hours earlier! I must confess to some suspicion of that number; I just can't believe that it could fall that dramatically. I suspect that it represents something rather different from the 12,000 mSv/hour I mentioned in a previous update.