Don't lose your cool

By Daniel Holz | March 16, 2011 11:54 pm

Japan is in the midst of a slow-motion nuclear meltdown. Each new day brings word of further problems. At this point three reactors have been flooded with seawater, and appear contained (at least for the time being). The news reports are incoherent and conflicting, and nobody seems to really know what’s happening. This may be because the information is not public. Or it could be because the situation on the ground is fundamentally incoherent. You can’t exactly walk up to reactor #2, open the door, and take a peek inside. Amazingly, the best up-to-date resource appears to be wikipedia (which incorporates the useful summary tables from the Japan Atomic Industrial Forum).

The earthquake happened at 2:26pm. Two minutes later, the Fukushima-Daiichi nuclear plant went into SCRAM mode, and shut down. The control rods were inserted. The diesel generators fired up. Everything worked to plan.

The Fukushima-Daiichi plants are boiling water reactors. In simplest terms, this is just a pile of radioactive material (generally uranium) which gets hot (literally hot, not just radioactive). You run water over it, generate superheated water and steam, drive a turbine, and produce electricity. Instead of burning coal, you use radioactive decay as the source of heat, but otherwise the basic mechanism is surprisingly similar to a conventional power plant. You turn off a nuclear reactor by inserting control rods, which absorb a lot of the neutrons, and inhibit further fission reactions. So, two minutes after the quake, the control rods were inserted, and the reactors were no longer undergoing nuclear fission. However, one of the peculiarities of nuclear power is that even after the reactor is shut “off” there is still a significant amount of residual radioactive material. This material continues to decay, generating significant heat (>10 megawatt; by now [almost a week later] it’s ~1 megawatt, enough to power a thousand homes). Thus, even after turning a reactor off, it still generates significant power for a few weeks, and the resulting heat needs to be removed and the radioactive core kept cool . And to do this, you need to pump in a lot of water (ideally thousands of gallons/min) at high pressure. And this requires a fair amount of power.

The plant was working perfectly for roughly 30 minutes after the earthquake. The tsunami was on its way, but the plant operators were blind to it. Had they known, they could have depressurized the nuclear cores in anticipation. But they were focused on riding out the earthquake, which they did admirably. And then the tsunami hit. Just a few years ago, after the tsunami in the Indian Ocean, the Fukushima-Daiichi plant was upgraded to deal with a worst-case, 5.3 meter tsunami. The wave that hit the plant last Friday was roughly 10 meters high. It swamped the diesel generators, as well as the fuel tanks and the switching station. The system was “live” because of the SCRAM, and the local electrical grid got fried. Fortunately there were backup batteries, which lasted another 9.5 hours. At around midnight the batteries ran out of power, and the plant was no longer able to cool its reactor cores. At this point, the Troubles began.

As the core starts to heat up, it boils off the surrounding water. Eventually the fuel rods are exposed to the air. This causes the core to heat up even faster, and also causes a reaction with the zirconium cladding (which holds the uranium fuel pellets in place), generating hydrogen gas. Without any cooling, the fuel gets hot (> 1500 K/2200 F), and starts to melt. The hydrogen gas collects, and eventually explodes (think Hindenberg). This happened in reactor #1 on Saturday, blowing the roof off of the reactor building, but leaving the containment vessel (which is ~1 meter thick steel) intact. On Monday a similar explosion happened to #3, and on Tuesday there was an explosion at #2. Both of their containment vessels were probably compromised. Rupturing a containment vessel is very bad. So long as most of the radioactive material is contained, the damage to the outside world is similarly contained (modulo venting of various radioactive gas, which has been happening, but not at profoundly dangerous levels). Once a containment vessel is ruptured, the radioactive material can end up anywhere; the sky’s the limit. Chernobyl did not have a containment vessel.

The current situation seems to be that seawater is being pumped into all three broken reactors (#1–3), and they are in thermal control. It seems likely that all three sets of fuel rods are partially melted and damaged. It also seems likely that the containment vessels in #2 and #3 have been compromised, although probably not severely. There are some concerns about spent fuel rods in pools near reactors #3 and #4. So long as the rods are covered in sufficient water, they are stable. If the rods are exposed, they heat up. And when they get hot, they start to burn through their cladding, and emit radioactive material. These pools are not within containment vessels, and therefore they are potentially even more dangerous than the cores of active reactors. Their radioactive emission goes directly into the surroundings. But so long as there is water in the pools, they should be fine. The latest claim (by the Chairman of the United States Nuclear Regulatory Commission) is that the storage pool at the #4 reactor has little to no water. If true, this is a very ominous development.

This is by far the most dire situation on the planet at the moment. It has the world’s attention. We’ve had almost a week. Why can’t we just fix it? There are a number of serious complications. First, there’s the issue of radiation. People are unable to walk up to most of the buildings and see what’s going on, lest they get immediate and severe radiation poisoning. There are remote sensors and cameras, but fundamentally everyone is guessing as to what’s happening inside. Even if we knew exactly how things looked, it’s still a major engineering feat to get the appropriate amount of water running through these highly complex systems to do the cooling. There have been explosions, there are stuck valves, there are broken pumps, there are ongoing fires. The world’s resources are focused on this problem. Millions of lives potentially depend upon the outcome. And, thus far, progress has been haphazard and halting, despite heroic efforts on the part of the Japanese crew. The engineering challenges may simply be too great.

The worst-case scenario for the Daiichi reactors plays out something like this: 1. the storage pool at #4 is indeed dry. Because it’s uncontained, the radiation levels in the area get very high. Everyone needs to evacuate the complex. 2. Without anyone manning the cooling systems, the cooling stops. Everything overheats. 3. There are various explosions, resulting in a breach to a containment vessel. 4. There is a subsequent steam explosion, and a plume of radioactive material is generated. 5. Wind carries the plume in the direction of Tokyo (world’s largest metropolis), a mere 140 miles (225 km) away. We can’t even contemplate trying to evacuate and treat a city of 35 million people. As far as I can tell, things do not appear to be headed in this direction. But such an outcome is unfortunately not outside the realm of possibility, and just contemplating this should freak you out. But, to reiterate, it’s very unlikely, and a lot of things would have to go catastrophically wrong. I’d love to quantify just how unlikely, but cannot. My guess is that nobody can, since there are too many uncertainties, and we’re fundamentally in uncharted territory.

The best-case scenario, and probably most likely, is that the Fukushima-Daiichi plant will limp along, but without any catastrophic events (such as a major Chernobyl-style radioactive explosion and fire). The fuel will continue to cool, the fires will be put out, the amount of radiation will subside, and eventually the entire site will be entombed and become a testament to human hubris.

CATEGORIZED UNDER: News, Technology, Top Posts
  • Susanne

    I partly disagree with what you’re saying. Sure, radiation is a problem. But the main problem is that the plant is cut off from all resources and located in a devastated region. They have no electricity and not even enough fuel to power emergency generators and pumps. But there is good news. A power line is presently being installed, and pump trucks are being brought there. Once the workers have all the access to resources they need, they are in a position to get things back under control.

    As for your unlikely worst-case scenario, I wish you hadn’t written this. I am a theoretical physicist living in Tokyo. These past days, media reactions have been way over the top and a *lot* of unease and fear has been generated, more than is needed. We have to live every day in this climate of panic that is being created around us. Do you want the 36 million people living in Greater Tokyo to freak out? I don’t. I’m one of them.

    As an aside, the latest radiation measurement I’ve taken on my balcony in Tokyo is 0.15 micro Sievert per hour, essentially background.

  • http://fixerdave.blogspot.com Fixerdave

    Also, don’t forget to factor in human failures… maybe Wikipedia can make a chart of that too. We’ve got people around here (on the other side of the Pacific, which is nearly the other side of the planet), self-medicating with iodine tablets. The Japanese, so far at least, appear to be quite sensible about the whole thing… so far. But, you don’t need an official evacuation of Tokyo, just a panicked mob-exodus will cause mayhem way up on the stupid-scale.

    Of course, the “we’re having a minor emergency” to “the emergency pump cooling the reactor ran out of fuel” plant owner announcements aren’t building a lot of trust either. Because of that, best case, nuclear engineering as a new career just got flushed down the toilet, unless you want to specialise in decommissioning.

    Best case… well, we’re already way past what I was considering best-case at the start. Best case now? How about the plant owners are actually telling us everything that’s gone wrong – and there are no more surprise best-case resets in the coming days. I’m getting tired of those.

  • Susanne

    Another thing: the predominant wind pattern is off-shore. That the power plant is on the shore was unfortunate for the tsunami, but probably not by chance. Like this, everything gets blown away from inhabitated places.

  • Susanne

    @Fixerdave: you think it’s the fault of the plant owners that the fuel reserves and backup systems and everything else has been swept away by a tsunami which surpasses everything in human memory for at least the last 1000 years?
    You have to realize that there has been a natural disaster surpassing the worst expectations. Given this circumstance, they are doing their utmost.

  • tudza

    Human hubris?

  • joe

    Aren’t *you* a testament to human hubris?

  • http://thebeautifulstars.blogspot.com/ Karen Masters

    tuzda – I wasn’t sure what ‘human hubris’ meant exactly either.

    From wikipedia: “Hubris (pronounced /ˈhjuːbrɪs/), also hybris, means extreme haughtiness or arrogance. Hubris often indicates being out of touch with reality and overestimating one’s own competence or capabilities, especially for people in positions of power.”

    So there you go. Not sure I agree with the sentiment though – seems like if the best case scenario happens it’s actually quite a success – that a nuclear plant could survive such an extreme natural disaster. I’m keeping my fingers crossed they’ll have it all under control eventually.

    (FYI I have a physics degree, not that that matters for looking up rarely used English words!).

  • James

    Out of interest, what form does the emitted radioactive material take? (ie. particulate or radioactive gas?) I ask because a lot of people in Tokyo appear to be wearing face masks, and I wonder how much good they will do.

  • MB

    For a significantly less pessimistic take on the “worst case” scenario, see

    http://www.theregister.co.uk/2011/03/16/fukushima_wednesday/

    (Click on “More from this author” for previous updates.) People keep talking about wind-carried radioactive plumes without any indication of the radioactivity level or the speed with which it decays away. You can measure such a plume not just to Tokyo but all the way to the States and it still doesn’t mean that it *ever* posed a real danger outside the areas already evacuated.

    See also

    http://ukinjapan.fco.gov.uk/en/news/?view=News&id=566811882

    again about another worst case scenario where any danger is still confined to within a few 10s of km.

  • http://mirror2image@wordpress.com Serge

    In more dire, but similar in principle situation, in Chernobyl Soviet authorities declared partial mobilization in several military districts (mostly chemical defense and transport troops) and just sent people in, trying limit exposure time where possible. Existing remote control vehicles weren’t working and even helicopters malfunctioned due to high radiation, and new rad-hardened robot development was just started. The thing is, army ultimately exists to protect people, whatever it cost to army personnel. If the situation become critical and civilian personnel would refuse continue to work Japanese army will probably be sent in. I don’t believe Japanese would sacrifice Tokyo because no one is manning reactors.

  • Pouria

    @8 James:
    I’m pretty sure I’ve seen pictures long before the accident where the people of Tokyo were wearing masks (big metropolitan area with poor air quality?). So I don’t think it’s something that’s popped up due to this.

    But to answer the question, I don’t think it will help against the radiation if it gets blown their way, the radiation will affect the body without having to be inhaled.

    /P

  • Chrysoprase

    @James: People in Japan wear facemasks because they believe it helps reduce the spread of contagious illnesses (false) and that it helps with allergies (true). People have heard that they are safe from radioactive isotopes if they do not inhale them or get them into open wounds (not sure), but I don`t think the facemasks will help with that (not sure).

  • http://telescoper.wordpress.com Peter Coles

    It seems clear to me that the operation to cool the reactors is not working – the helicopters sent in today look like desperation to me. They carry far too little water, and they are unable to place it accurately.

    What I don’t understand is why they don’t get a flotilla of ships up the plant (with crews in full radiological protection gear). After all, it’s right on the sea. Fire-fighting vessels or suchlike could pump seawater over the reactors directly from the sea and once in place the crews could leave them.

    It would even be worth running a big ship aground if necessary to get more water onto the reactors.

  • Pingback: Desperate Measures « In the Dark

  • XPT

    Thank you for this clear explanation! Maybe some details are missing as commenters are pointing out, but this is the first coherent report I’ve read.

  • Andy

    Dumb question about spent fuel rods: if the fuel in them is spent, why do they still get hot if they aren’t in water? Second, if they are still dangerous, why aren’t they in a containment building?

  • http://telescoper.wordpress.com Peter Coles

    Andy,

    Although the fuel in the rods is no longer participating in the chain reactions that go on inside the reactor, they are kept hot by radioactive decays going on within them and must be cooled continuously, usually with water, until the rate of decays falls sufficiently to allow them to be moved.

    The spent fuel ponds containing the rods are within the reactor building.

    Peter

  • http://theradioactivegan.blogspot.com radioactivegan

    @Andy – Spent fuel is a bit of a misnomer – there is still a good bit of uranium in the rods, but that is not the concern here. The rods heat up because of the decay products contained in them after being used in the reactor. Some of these isotopes are short-lived, some longer. Spent fuel is kept in a spent fuel pool for 10 – 20 years (depending on regulations) and then moved to dry cask storage after that. More reasonably, the fuel could be reprocessed to remove the still useful material, leaving us with a much smaller amount of true waste to deal with. As to the location of spent fuel pools, I’m not really sure where this is. I assume it is housed in some kind of containment building, but nothing like the primary containment surrounding the reactor.

  • Mandeep

    Great summary of the current situation Dan – and you don’t address it here, i guess because the circumstances are urgent, but of course the issue of nuclear power and safety will come up soon after this. I know it may seem i’m jumping the gun by addressing this, but it’s the part that’s most relevant going into the future, and as long as the *worst* case scenario doesn’t come to be in the coming weeks (which seems rather unlikely given what Susanne says above), this reactor issue should be settled relatively soon, and we should be able to get back to these important discussions of how best to make energy for our societies, in the future.

    And i’m sure the issue has already been raised in various places — because climate change is globally our *biggest* issue in the coming decades (along with oil running out, as it will, *someday* — and we may already have passed peak oil globally).

    So i was in recent times *just* starting to ‘warm up’ (hah) to the idea of nuke power again, though not too strongly — been not too supportive of it for a long time, for the always unforeseen dangers like this, for the unpleasantness of the waste, and of the mining itself, which is generally none too ecologically-minded (esp e.g. for the Navajo of AZ). But anyway, whatever my opinions — it’s quite clear this is going to turn US (and likely world) opinion very much against nuke power again.

    And i think that could be *good* for the burgeoning wind and solar industries, which is where in the US we have *vast* potential, and much more minimal env’l impact in their production, on the whole, as well as not having *any* of the inherent risks of nuclear, or carbon-based, energy production going into the future. This is why i’ve always felt these renewable sources are what truly what should be supported maximally within the US.

    European countries have been taking the lead on much of this (esp Spain, Portugal, the UK, the Netherlands, Denmark), in recent years, as well as China, but under the Obama Admin we’ve started to make *some* headway in the last couple of years.

    Yes, wind and solar are much less energy *intense* at the point of generation, generally — but this can be a very good thing in many ways, as we’re seeing with this reactor issue. Also — the decentralization of power, and the fact that *every* homeowner can create at least some of the energy h/her family uses, can be seen as quite positive, in the end, also.

    I know controlled fusion in the far (*far*?) future could be just what the doctor ordered, and building ITER in the next decade or so in France should be a big step in that direction — but as of now, it still looks to be a long way off. So we have to think of what to do in the meantime.

    Again — this may be seen to be ‘jumping the gun’ a bit, but we’ll all be having more of these discussions soon, so i thought this would be a useful little contribution, here.

    But in the meantime — i’ll be crossing my fingers for Japan, and that this whole thing get contained and settled, soon…

  • http://theradioactivegan.blogspot.com radioactivegan

    This is sensationalism at best. I think you are painting a much, much graver picture of the situation than needs to be, and the comment “such as a major Chernobyl-style radioactive explosion and fire” is outrageous and, frankly, irresponsible. It is IMPOSSIBLE for these reactors to do anything close to what happened at Chernobyl, and it is dangerous to suggest they might. I expect better from this blog.

  • cy

    Sounds like the media is really picking up on the “radiation reaching west coast” story.

    Here’s the analogy I came up with.

    You have a 5 gallon bucket of water. You drop in 5 drops of red food coloring. At first you have a concentrated area of coloring (radiation) at the top of the bucket (nuclear plant). Over time, it spreads out and eventually the food coloring gets to the bottom of the bucket (the United States), but by then its been diluted and spread out so much that you can barely notice a rose colored tint to the water.

  • Jason Dick

    While you have some good information here, Daniel, the tone really is fearmongering bullcrap. Three main points:
    1. The nuclear disaster will almost certainly be just a minuscule blip on top of the massive disaster of the tsunami. It is the earthquake and tsunami itself which are the major disaster at the moment, not this nuclear plant.
    2. The long-lasting fire at the Chernobyl plant was a result of using graphite for cooling. The graphite caught fire. There is nothing like that at the Fukushima plant.
    3. Even though individual nuclear disasters can be nasty, on average they tend to be significantly safer and less polluting than any other power generation method we have (except perhaps solar).

    Hubris this is not. Nuclear power is a very safe and clean power generation method. And furthermore, more modern reactor designs are dramatically safer than the Fukushima plant (which is 40 years old).

  • Low Math, Meekly Interacting

    Something that pales against the human toll of the tsunami, but that I can’t help but be haunted by is the fate of the small crew at the plant. Some of them may already be dead men and women walking. If so, they likely are well aware of of it.

  • http://danielholz.com daniel

    @susanne, @radioactivegan @Jason Dick: When I say “worst case”, I mean “worst case”. Yes, generally winds blow offshore, not in the direction of Tokyo. And yes, most of the radiation is contained, there won’t be a graphite fire, etc., etc. But, unless you have information that the rest of us don’t have, you don’t really know how things are going to play out. If the containment vessels rupture, or the spent-fuel rod pools fully evaporate, a significant amount of radioactive material could be produced. And, as far as I know, you can’t guarantee that the winds won’t head in the direction of Tokyo. I don’t claim any of this is likely, but it’s by no means outside the realm of possibility. And the repercussions are profound and disturbing. That is why everyone is making such a big deal about this. People in California taking Iodine is craziness. People in Tokyo starting to get nervous makes total sense. Note that the latest news says that the mixed-oxide (read: plutonium) rods may be exposed. Radiation levels of 250 millisievert/hour are present 100 ft above the plant.

  • Cathy

    I doubt the crew remaining on site are doing anything without wearing lead lined hazmat suits right now. The reason so many workers at Chernobyl died was because of inadequate protection against the radiation – they had face masks and shovels. Any time the radiation spikes high enough to penetrate their protective gear, the Japanese workers are being evacuated from the site.

  • http://danielholz.com daniel

    @Peter: Firefighting ships seem like a natural thing to try (they’ve tried firetrucks and helicopters, but ships can generate a significantly larger flow). I would also expect that there are radiation-hardened robots that could help? I imagine *every* contingency is being considered at this point. Desperate times call for desperate measures.

    @Andy: As Peter said, the spent fuel pools are within the reactor buildings, but outside (and above) the primary containment vessels. A sketch of the geometry can be found in the images at the BBC website.

  • http://danielholz.com daniel

    @Mandeep: I figured I’d let the current situation settle down before posting on the future of nuclear power. One message that is certainly being lost is that these reactors survived one of the biggest earthquakes ever, with hardly a scratch. It is remarkable how well everything was working. Until the tsunami hit, that is.

  • jpd

    “Nuclear power is a very safe and clean power generation method. And furthermore, more modern reactor designs are dramatically safer than the Fukushima plant (which is 40 years old).”

    in theory you may be right, in practice you are obviously wrong.
    GE engineers resigned in 1975 over concerns about the design of this reactor.

  • John

    Great post, Dan! You beat me to it! (This is your co-blogger, John)

    I have been following this story obsessively myself, and it has been damned scary. I am no expert in nuclear power plant engineering, just a high energy physicist. But it is abundantly clear that the biggest danger is that in one of the three fueled reactors, or one of the six spent fuel pools, the fuel rod zirconium claddings melt and/or burn and then the fuel itself melts and basically puddles at the bottom of the reactor vessel or spent fuel pool. Once it is in some sort of molten puddle, there may be no way to prevent the fuel from going critical once again, with dramatic, and yes, Chernobyl-scale, consequences.

    To say this scenario is impossible, radioactivegan, is exactly the type of hubris Dan means. In fact, it seems almost inevitable if the fuel and spent fuel is not kept cool. This new power line may allow them to much more reliably pump cooled water into the reactor cores, using the primary cooling systems. But the piping and valves and controls may have been damaged by the enormous hydrogen explosions that have taken place, particularly in reactor 3 (the one which has plutonium mixed-oxide fuel).

    So it may require getting people close to the spent fuel pools or reactors to get water into them, using external pumps and hoses, etc. To accomplish this could require literal suicide missions depending on how intense the radiation is near the reactors. I am sure there will be volunteers, and it is on these brave people that Japan depends. We are not out of the woods yet.

  • Georg

    1st, the fuel is not uranium, but uranium dioxide
    2nd the steam generated from contact with the fuel rods is not fed to turbines,
    but first transfers its heat in a heat exchanger to a second water system,
    which then drives the turbines afaik

  • http://facingzionwards.blogspot.com/ Luke Lea

    “But, unless you have information that the rest of us don’t have, you don’t really know how things are going to play out.”

    In that case, here is a worser than worst case scenario: in the aftermath of the magnitude 8.9 earthquake a volcanic eruption occurs directly beneath the Fukushima-Daiichi plant, blasting their contents into the atmosphere.

    The question is, should we prepare for this eventuality or admit that at some point we are succumbing to radiation hysteria? Some kind of cost-benefit analysis is in order, comparing the estimated costs of hysteria times the likelihood that we are in the midst of an episode of mass hysteria (an element of human nature not unknown to history) to the estimated costs of various “worst-case” scenarios in relation to their estimated probabilities.

    Among the possible costs of hysteria we should count, in the short-run, the needless human suffering created by the Japanese government’s evacuation orders around the plant, adding to the tens of thousands of people already left homeless in the aftermath of the Tsunami. In the long-run it would include the direct and indirect costs of forgoing the nuclear power option in supplying society’s energy needs.

    I submit we are way over the line short-run, based on available knowledge, and that the jury is still out long-run, though the signs are not promising.

  • ChuckWhite

    daniel, I have posted a very positive review of your article on Crooks and Liars and gotten at least on comment of thanks as a result.

  • ChuckWhite

    daniel, I have posted a very positive review of your article on Crooks and Liars and gotten at least one comment of thanks as a result.

    Thank you, daniel, for a clear, layman’s view of the principles, the chain of events and the possible outcomes … without hyperbole.

  • Cathy

    Just read in another article that the workers are being retired after 12-24 hours of work, and the biggest danger they’re going to be facing soon is a shortage of manpower. The maximum exposure each one can recieve has been raised from 100 mSv to 250, although the most anyone has been officially exposed to so far is one worker who hit 114 and was immediately retired. They are not “dead men walking” but they will certainly have to be monitored for the rest of their lives for potential after effects.

  • Nex

    Nuclear power is still the way to go, all this disaster shows is that we need better reactor designs, and better emergency response. All the problems which plague this plant are avoidable.

    First and foremost it is now clear that all nuclear power plants should be out of reach of even the most improbable tsunami.

    Second, plants need ways to safely dispose of hydrogen build up.

    Third we need national or international emergency response teams with radiation hardened robots, high capacity pumps, and generators capable of being airlifted to any destination and installing reliable emergency cooling in 48 hours.

  • http://togroklife.com Greg

    @jpd – only 1 of the reactors at Fukushima 1 is a BWR3, the other affected reactors are BWR4

  • algernon

    Honestly, I find your final comment about “human hubris” to be quite off mark.

    From the info I’ve gathered around the net, analysis of historical data about that fault indicated a scenario consisting in a future earthquake of about 8.0-8.3 magnitude. And as you stated, they were basically ready to deal with waves up to 5 meters as a result of the quake.

    What they got instead was the Big One, no kidding. This is a magnitude 9.0 earthquake and that 0.7 extra degrees over the worst-case prediction make a lot of difference: they got an event ELEVEN times bigger than the worst-case scenario, in terms of seismic moment.

    Because of that, I personally just don’t feel like I should place the blame on the Japanese, at any rate, for that incident. They’re doing what they can to deal with the situation, despite the fact that the surrounding coastal region lays devastated beyond imagination.

  • http://fixerdave.blogspot.com Fixerdave

    @Susanne says “you think it’s the fault of the plant owners that the fuel reserves and backup systems and everything else has been swept away by a tsunami which surpasses everything in human memory for at least the last 1000 years?
    You have to realize that there has been a natural disaster surpassing the worst expectations. Given this circumstance, they are doing their utmost.”

    No, but I think the plant owners are at fault for continually under-reporting the damage, then continually upping the best-case scale to the old worst-case scenario. I mean, if the initial report was a little more “we’re having very serious problems,” which, at this point, seems a little more realistic, then I might be a little more accepting of running out of gas.

    As it stands, what little industry trust that existed before this all started has pretty much been flushed. This is, in my opinion, a serious human failure. Their attempts to save face have cost a lot of people their future careers.

    I am (possibly had) planning (planned?) a trip to Japan in a few weeks… A few days ago, I was all “no big deal, we’ll still go.” Right now, my wife is holding off buying tickets, waiting for the next best-case reset by the plant owners. I’m getting frustrated, and I’m on the other side of the ocean. The people living in Tokyo must be getting very angry. If these owners keep hammering away at the trust the Tokyo people have, it has the potential to get very, very ugly – even without any significant radiation.

  • Brian

    So I shared your post on Google reader to all my friends and we all agreed that this was an excellent article. None of us had a really good grasp on what exactly is going on and what is going wrong over there. All we know is what CNN and the rest have showed which is mostly jumbled and wrong. You presented us with the info in a very useful way for non nuclear engineers. as my friend said, “It was incredibly informative and very well written to provide a simple explanation of the situation to someone who previously got all their knowledge of nuclear power from The Simpsons.” So, thanks for the great post.

  • dave chamberlin

    It is not fear mongering to explore the worst case scenario, if that worst case scenario is possible. To not explore what the ramifications shall be is just about as stupid as placing your back up diesel generators in the basement (flooded) and the stored fuel rods overhead .

    Now is not the time for ideology masked as clear thinking , and I appreciate efforts by many to approach this as a chess game thinking many moves ahead. I respectfully disagree that the worst case scenario (runaway meltdown too radioactive for anybody to get close enough to stop it) is highly unlikely. I have absolutely no confidence that the managers of this accident will at his point get it under control, and furthermore neither do a number of informed people at this point.

    My heart goes out to the 35 million people living in Tokyo. The six reactors at this site have considerably more uranium than Chernobyl and it is likely that it will transform into a number of molten globs each of 5000 degrees. Even though three of the reactors were not operating at the time of the earthquake all six have to be counted because they all had stored uranium in them. Do not kill the messenger, it is what it is. The worst case scenario is that if what is sitting below this uranium melts at a lower temperature than the uranium (it will) than the uranium will simply sink right on down through it until it hits the water table.

    People in Tokyo even in the worst case scenario will not receive lethal doses but many have chosen and will choose to leave for the duration of the catastrophe. Now is the time not just for realism but reaching out and helping those in need. In the days to come hopefully what I fear will be proven wrong, we will see.

  • Brad

    I’d like to ask the learned folks here a couple questions, if I may:

    My understanding is that radiation takes two forms: particulate and electromagnetic. Radioactive isotopes spontaneously emit particles like neutrons and electrons as well as X-rays, gamma rays, etc.

    My question is, when radiation levels are measured at some distance away from the plant, is that radiation largely due to particulate, electromagnetic, or both types of radiation?

    Relatedly, are the evacuation radii suggested by the U.S. and imposed by the Japanese derived from estimates of how far electromagnetic radiation could be emitted from the plant in the event of a major catastrophe and/or does it have to do with the potential spread of particulates via air currents?

    Thanks.

  • http://kforcounter.blogspot.com Cody

    I recommend arms control wonk for accurate assessments of the ongoing situation.

    Also, this post was very informative, but the worst case scenario does feel a bit like fear mongering, and I disagree with the hubris comment, though mostly this all seems like a matter of opinion…

    I am unhappy with arguments of the form, “this technology has had disastrous consequences -> therefore we should avoid this technology.” If more people understood science the conclusion could maybe be, “-> therefore we need more and better research into the nature of this technology, it’s risks, how to prevent them, deal with consequences of unforeseen events, etc.” And only after having a complete understanding of the technology should a decision be made. And those who don’t understand ought not to have much of a say in the decision.

    Which is why more and better education is so damned important.

  • http://facingzionwards.blogspot.com/ Luke Lea

    Onion headline: A TSUNAMI OF HYSTERIA SWEEPS ACROSS THE EARTH, Dwarfing Tsunami in Japan

  • Alice Moore
  • http://itia.ntua.gr/antonis/ Antonis Christofides

    @Susanne says “you think it’s the fault of the plant owners that the fuel reserves and backup systems and everything else has been swept away by a tsunami which surpasses everything in human memory for at least the last 1000 years?”

    I doubt it surpasses the 2004 in India, and it also does not seem to surpass Lisbon 1755 in terms of the devastation it brought. Note, also, that 1000 years is not really much. Major engineering works, such as dams, are designed to withstand disasters that happen, on the average, once in a thousand years. This seems OK until you realize the number of dams (or nuclear plants, for that matter) that exist in the world. The reason we don’t see a dam collapsing every year or so is that engineers habitually make the structures stronger than their specifications say – such as in this case, where, according to a reader above, Fukushima I was designed for 8.3 but it withstood 9.0.

    @Nex: “all nuclear power plants should be out of reach of even the most improbable tsunami.” There is no such thing as “the most improbable tsunami.” There is a once-in-a-thousand-years tsunami, a one in a million, a one in a billion, and so on. You choose a lower probability, and the cost increases. You have to draw a line somewhere.

  • Gregg
  • Charlie

    I wish that the media (or blogs like this) did a better job of explaining the difference between penetrating radiation (such as gamma and neutrons directly off the core or very short lived isotopes) and radioactive contamination (such as alpha emitters that don’t do much unless internalized). It’s all just called “radiation” on the news which is not very helpful. The resulting ignorance leads to individuals (or reporters) waiving Geiger counters around in Tokyo apparently at the air itself, which is complete madness. If there is enough contamination to see with your Geiger counter this way (rather than on a swipe or air filter) then things are very bad indeed.

  • Truly Anomalous

    Daniel, thanks for the objective and level-headed explanation of this important subject.

    I read about the following in Cat Dynamics, but you can follow the radiation level-Geiger counts – near Tokyo in real-time, online here (in Japanese):

    http://park18.wakwak.com/~weather/geiger_index.html

    I have faith that the Japanese will be able to eventually take care of this problem.

  • dave chamberlin

    When I mention worst case scenario it doesn’t mean that there isn’t enough time for the ingenious use of mechanical systems to guide water where it needs to go, Nobody knows what is going to happen.

  • http://rumblingsfromthespeaker.blogspot.com Bruce Cohen (Speaker to Managers)

    Jason DIck @ 22:
    4. The Chernobyl reactor was running (they tried to scram it and the control rods jammed, resulting in a pulse of heat output 10 times normal operating power), and the core blew up; all of the Fukushima reactors are shut down and have been for several days. So no explosion even remotely comparable to Chernobyl (equivalent to about 10 tons of TNT) can happen at Fukushima even if the spent fuel rods melt down completely and explode.

    I’d like to ask everyone here why they feel it necessary to obsessively contemplate the worst-case scenario. There’s nothing any of us can to prevent it, nor is it likely there’s anything we can do to prepare for it (unless we’re living in Japan, which most of us aren’t). And we really don’t know what contingencies the people dealing with the problem are considering, nor do we know what the detailed facts on the ground are, or what viable options actually exist (and I think there’s a great deal of hubris in assuming that we, thousands of miles away, can make useful determinations about what will or won’t work that would help them).

    Why shouldn’t we consider the worst? Well, doing so is creating a climate of panic, which is affecting the ability of people at the sharp end to deal with the problems. Already some of the drivers of the emergency supply trucks going to the evacuees have refused to make the trip because they think they people they’re supposed to help are radioactive, and will make the drivers sick from contact. And that sort of thinking really isn’t very different from the kind of panicked sensation-mongering that’s going out in most of the news media and on the blogosphere.

  • Pingback: Japan Nuclear Crisis « The Knowledge Board

  • Andrew

    The real reason nuclear power is a failure as nothing to do with this situation. It’s all about cost. Nuclear power is hugely expensive. I suggest reading the Union of Concerned Scientists’ site on nuclear power.

    Sure, it’s interesting technology and we should put more R&D into it, but paying boatloads for the nuclear reactors that are available today is folly.

    All these extra safety measures being suggested here put nuclear power even further out of range for a market competitive price.

    Tokyo will likely be safe. The probably bad-case is that a hundred thousand people will never be able to move back to their home. That’s a bad outcome, even if there are no deaths.
    Even strong supporters of nuclear power like the professor writing for Brave New Climate is admitting that he was wrong.

  • Nex

    Antonis Christofides: @Nex: “all nuclear power plants should be out of reach of even the most improbable tsunami.” There is no such thing as “the most improbable tsunami.” There is a once-in-a-thousand-years tsunami, a one in a million, a one in a billion, and so on. You choose a lower probability, and the cost increases. You have to draw a line somewhere.

    I used the term rather loosely, but a plant located, say, 500 meters above sea level should be safe from even a one-in-a-million-years tsunami, and building on a higher ground doesn’t necessarily mean higher costs.

  • AnonymousSnowboarder

    This is one of the better summaries of events I have read. Also recommend checking in with the armscontrolwonk.com for updates and commentary.

    The most egregious thing to come out of this (there are a few) is that the US and Japan apparently only mandate 8-12 hours backup battery power. Euroland is better, 24 (might be 48). Clearly nobody has thought out of the box to contemplate various disaster scenarios. Had there been 3 days backup (72 hours) we might not be in this mess or certainly anywhere near as deeply.

  • at

    There is a Tokyo government agency which publishes hourly readings for radioactive iodine and cesium isotopes in the air. Looking at the latest data, there is now a whopping … wait for it… ZERO Bq/m3 of the stuff blowing around the city.

    Move along, nothing to see here.

  • anon

    Seems ironic (by which I mean dumb) that the backup generators are at ground level while the pool for spent fuel rods, which must be kept covered with water is high up in the containment facility.

    Oh! If only that had been reversed.

    Srsly, 5 meter waves along the Pacific Rim and that’s that, we’ve done our job now.

    Can someone here tell me what language “Tsunami” comes from?
    Oh hey, Daniel, check this out, you won’t believe the irony:

    “Tsunamis are a frequent occurrence in Japan; approximately 195 events have been recorded.[4] Owing to the immense volumes of water and the high energy involved, tsunamis can devastate coastal regions.”

    IT TURNS OUT IT’s A JAPANESE WORD! WHO WOULD BELIEVE THAT COINCIDENCE?

    When I visited Rackspace in 2003, they kept their backup generators on the third floor of a parking garage, and that was in Austin Texas.

    So they had power from the nearby nukes, backed up with generators at ground level, but they had no plans for what happens when the backup generators fail for more than 8 hours? Not even a manual, just hook up the fire engine right here set of piping?

    And on top of that the reliable reports are that the fuel rods in the spent pool were restacked overloading the natural cooling of the pool.

    And Daniel, I’m supposed to be impressed with these idiots, it’s all working as planned, excellent Smithers, excellent. Stupid anti-vax, anti-agw idiots, I’m here at discovermag to tell ya the science!!!!!!

  • spyder

    Just a couple of new facts came in. The weather is about to change and the wind flow will sadly be from the Northeast over the coast in Japan. Tepco, in the last three hours, released the latest data from an overflight that the radiation levels have risen to 20 msvts per hour rate over the site. That is roughly a seven-fold increase given the previous readings. That is all.

  • http://danielholz.com daniel

    I’m surprised that people are taking umbrage with my use of the phrase “humanity’s hubris”. This is not meant to be a slight to the Japanese workers at the plant, nor the (American) plant engineers. Given that the plant is almost 40 years old, it’s a marvel of engineering, having withstood one of the most powerful earthquakes in history. The point is that humanity, no matter how clever we think we are, can always be unpleasantly surprised. We are playing with fire. The goal is to build something invincible. And yet, Nature will find a way through.

  • anon

    “You can’t exactly walk up to reactor #2, open the door, and take a peek inside.”

    I don’t understand exactly why we can’t do that.

    It’s 2011 not 1971 and not 1979, how come every nuclear power plant isn’t completely covered in webcams?

    If you even pretended to be a real journalist, you might not stop at wiki, but call up scientists, engineers, the plant owners, regulatory bodies and help us out: why aren’t there webcams, IR cams, and all sorts of remote sensing devices everywhere within the reactor building, by the spent fuel pol, and even within the steel containment vessel?

    It’s 2011 not 1986 why are there no rad-hard robots either Asimo, Packbot, or Crow permanently stationed within the building? A Packbot, or packbot like robot would assist in clearing paths, viewing occluded areas, or even taking the place of bio-bots.

    Like uh, Danny, how much does a nuclear reactor cost compared to a robot?

    Anyway, it’s good for us all you don’t even pretend to be a journalist.

  • Jimbo

    Daniel,
    Your synopsis of the current situation appears consistent & informed, but I have a question which you, a member of the technical staff at LANL, are well positioned to answer in detail, if you can.
    I would expect that LANL, LLNL, ANL, & ORNL, are a state of the art repository on issues pertaining to nuclear reactor safety, control, & radiation. What can you tell us about what the national labs are doing to assist the Japanese ? Is it just information or are scientists, engineers, & techs working on materiel and/or novel approaches to helping the Japanese nuclear industry gain some measure of control of this horrible disaster ?
    I would imagine many of CVs readers are as interested as I am….

  • http://telescoper.wordpress.com Peter Coles

    Here’s a thorough analysis of the situation by Frank Shu (with equations).

    http://www.asiaa.sinica.edu.tw/news/_upload/201103JapanNuclearAccident.pdf

  • Morbid

    Daniel,

    After SCRAM the effects of a tsunami would be felt within 30 minutes. Was a further problem initiated by the water flowing OUT TO SEA…all the seawater cooling pumps lost their ‘prime’, or sucked air – causing them to seize?

    Also, in a worst case, I have read (unsubstantiated) that if all six reactors melt down (including the spent fuel rods), the Fukushima-Daiichi nuclear plant would be 600 times more powerful than Chernobyl.

    Could you comment on these two speculations?

    Thanks

  • Tony Verow MD

    Daniel , Susanne et al. Thanks for an excellent discussion of this terrible situation. I am not a scientist, just a medical doctor. I have always been fascinated by nuclear power. Have there ever been any thoughts of reactor redesign so that in a “worst case scenario” (no ability to pump or control water, control rod manipulation lost, etc.) that fissile material could be physically separated in such a way as to generate much less heat ? It might not be practical or easy from a day to day power generation standpoint, but it could make things much safer in the aftermath of a situation that we are seeing.

    I have done some reading on the previous incidents /accidents involving fissile material (Idaho Falls reactor accident, Leo Szilards death, Chernobyl) and have been struck by the idea that comprehensive forethought in preventing accidental or uncontrollable subcritical generation of excessive heat might be possible.

    In my own profession of anesthesiology there have been a lot of hard won lessons in the design of our mechanical ventilators and oxygen delivery devices to prevent iatrogenic (human error ) causes of death. Machines are simplified, “dumbed-down” and have multiply redundant systems to prevent the operator from subverting safeguards. Our anesthesia machines are designed to always deliver oxygen in the absence of electrical power (AC or battery supplied) or after gross operator error.

    To wit: is there a practical reactor design possible that could incorporate a “dead man” switch that would immediately separate fissile material so that in the event of a loss of control, the catastrophic heat generation would not occur or be very short lived ?

  • Low Math, Meekly Interacting

    I don’t think that my assessment of the plight of the volunteer crew at the plant was so far off.

    http://news.yahoo.com/s/yblog_thelookout/20110317/us_yblog_thelookout/worker-at-japanese-nuclear-plant-were-putting-our-lives-on-the-line

    I also would like to commend Daniel on a thorough, unsensational, entirely realistic summary of the true situation of the Fukushima plant, as good as anyone in his position and with his access to accurate knowledge could be expected to produce. I think the accusations above of fearmongering are quite unjustified.

  • Roman

    I’ve re-read the story of Chernobyl recently and it is a chilling read. Even though I was in the fallout zone at the time (Poland) and my then 4 yo daughter was given iodine (in liquid form as I can remember) I didn’t know much about the mechanisms of the disaster for a long time.
    Two things that struck me were that in the Chernobyl case, it was of highest priority at some point to REMOVE the water from the reactor to prevent catastrophic steam explosion and that genuine safety concerns initiated the fateful chain of events.

  • Mel

    Thanks for the recap that is neither alarmist nor dismissive of possible outcomes. There’s far too little of that going around right now! I think our fear of the word ‘radiation’ is in part a hold over from Cold War fears. We’re no longer afraid that the Russians are out to get us, but any kind of nuclear threat remains disproportionately terrifying.

    One question for you concerning the hydrogen explosions: you said that the hydrogen gas was produced when the zirconium cladding on the fuel rods began to melt. If that were the case, wouldn’t the hydrogen collect inside the containment vessel , and any explosion would have to happen there?

    Other explanations I’ve read said that the hydrogen was a result of superheated steam splitting into its component atoms. When the workers vented steam to reduce pressure in the core, they released it into the building (outside the containment vessel, inside the building walls) so it would have a few minutes for the majority of its radioactive components to break down before releasing it into the atmosphere. These sources said that the hydrogen collected inside the building, and ignited there, thus blowing the roof off without damaging the containment itself. It sounded like the goal was to help calm the public by reducing the (already minor) amount of released radiation even further, unfortunately the explosions were far more frightening and damaging than the radiation would have been.

    Can you speculate on which chain of events is accurate, or if there’s a more complicated explanation that I’m not understanding?

  • dave chamberlin

    The New York Times is the best source of in depth news coverage and the following information is a summary of what I read there and found to be of the most importance. The excellent news is power has been restored to reactors 5 and 6. The good news is yesterday, 3-17 is there was not a further decline in the situation. When the US says that there is no water in the spent fuel storage tank #4 they should simply be taken at their word as they have the intelligence gathering means to look directly into the building. This is terrible. There are 1479 spent fuel rods in the overhead storage tank at reactor 4, 548 of which are not spent but placed there while maintenance was going on in the reactor itself. These rods are covered in a zirconium cladding that will burn at a very high temperature when they get hot enough. The tank cannot be refilled because it is leaking. Helicopters have tried to drop water on this but they can’t get close enough and if they could what is the point, it will leak out anyway.

  • réalta fuar

    I’m not willing to let TEPCO off the hook for not planning for a disaster of this magnitude, great as it was. Given the location of the reactors, a disaster of this magnitude was pretty much a certainly, on a timescale of a century or so. Build enough dangerous things in enough dangerous places and you’re going to get dam collapses, slurry spills, reactor meltdowns: things you haven’t planned for because you thought they were too unlikely and thus too expensive to plan for. As has been pointed out, nature really doesn’t care what you think. There comes a point where the worst-case-scenario is truly unthinkable and one should instead think about other solutions. The fact that sufficient coolant water couldn’t be supplied on loss of power after 12 hours or so seems like a major failure in design. Coolant water is the one thing you obviously have to have in any failure scenario. I’m not particularly impressed by the reactors “surviving” the initial quake since for a quake of that magnitude, in or near that location, a huge tsunami is essentially guaranteed. Would 10 km further inland really been that much more expensive? You’d never design a bridge with a safety margin of only a factor of two. Everyone should remember that these reactors are about 40 years old and that the Japanese nuclear industry’s safety record isn’t really any better than that of the U.S. or France.
    Andrew @52 has made the most important commentary on this disaster: it’s all about cost. nuclear power is hugely expensive and only cost competitive in countries that don’t really have a choice (or at least THOUGHT they didn’t have a choice), like Japan. Pick any fancy, new, presumably safer design you want, and the price only goes up once you’ve put in the decade of research needed to commercialize your design of choice. Nuclear power seems to only be a viable solution at a) the South Pole or b) aboard a submarine.
    Best idea I’ve ever heard for nuclear power: Ireland should build a nuclear power reactor, but build it in France!

  • John

    I read today that the fuel in the spent fuel pool at reactor 4 is not all “spent”: they had removed the active fuel from #4 for inspection and rearranging, storing it in the spent fuel pool. There are 1479 fuel assemblies in the pool, many of them quite fissile.

    To my mind it seems highly probable that when the fire broke out on Weds. that it must have been the zirconium cladding burning off on at least some if not all of the rods. I have yet to hear a better explanation. This also explains why they put the fire out then it popped back up again.

    The assemblies are each put in square pigeonholes which I assume are made of steel. I presume that the steel got hot enough to at least slump. They cannot seem to put water into the SFP and have it stay and in any case, they only squirted 50 tons today; that pool is huge: from the diagrams it appears to be 10 m x 10 m x 15 m deep. That would hold 1500 tons of water alone. You can see yourself that the helicopter drops are pretty useless. So we can safely assume there is little if any water in there. There are reports that the steel liner is cracked, also. I think we can forget getting water in there by any means other than someone carrying a fire hose up there.

    But why have they not tried using a fire truck with an extension arm, and shooting in water through the side of the building (which burned away)? I realize that the radiation levels are very high, so they are trying to stay a distance away, but still…

    Anyway we have a very hot, if not molten, mass of steel, uranium/spent fuel (which basically has “every atomic isotope there is”), and all held up by concrete. What happens next?

    I actually think that if the entire mass becomes molten, eventually it will be a big uranium/steel “lava lamp” and the higher density uranium will, inevitably, sink. Eventually the whole bottom layer of the SFP will be molten uranium and heavy metals, about half a meter thick. (Do the math.) It will be getting hotter, and hotter, and hotter. Maybe leaking out through cracks in the concrete. A million kilograms of partially depleted uranium. Maybe it will already have begun to go critical, well before this, giving us a mass of molten steel sitting on top of it.

    What is wrong with this analysis? Something, I hope.

  • dave chamberlin

    response to John # 69

    What you deduce makes sense. It wouldn’t have been a fire, just a quick violent explosion if it was hydrogen. What else in the building would be flammable? Whatever is happening is not going to be put in the papers, nor should it be. The poor people of Japan are freaked out enough. You can assume that thermal imaging cameras flown by the drone planes know the exact temperature and experts in Washington and Japan can predict not only what has happened but may even be able to project what will happen in regards to reactor #4. They may not know the exact timing but they know that Uranium mass cannot come in contact with the water table underneath the thick concrete foundation. Roman in #65 makes a point that there will come a time very soon when water just creates more radioactive steam.

    We will only read later about the crack team of experts that are working right now on what the best course of action is.

  • Stella Elliott

    The International Atomic Energy Agency (IAEA) website has all the facts if you want publicly available information.

  • dave chamberlin

    It blows my mind there are two completely different stories being handed to the public regarding how things are going regarding something as important as a nuclear meltdown near a metropolitan area of 35 million people and nobody is talking about it. The Japanese have one version and the United States and the New York Times have another. The Japanese are highly motivated to downplay the seriousness to keep their population from freaking out further and the US and New York Times have nothing to gain by spinning the story in a negative direction.
    The situation is now being called stabilized, which is just about the last word I would use to describe a huge quantity of uranium that (if you believe the US State Department) is not being cooled in any way. The zirconium cladding has probably not burnt off yet because when it does it is projected to give off a far larger radioactive burst than we have seen so far. Regarding the IAEA, they have not visited the site yet but they plan to in the very near future, unbelievable.
    What the US is now recommending is to bury the mess in boron, sand, and concrete, just like they did in Chernobyl. The russians didn’t have robots but they might have got their money’s worth out of their considerable fleet of bombers as they bombed the hell out of Chernobyl for ten days with the products listed above.

    meanwhile, time’s a wasting.

  • dave davis

    A worse worst-case scenario is that the radioactive cloud gets pushed by prevailing winds towards North Korea. Consider that..

  • John

    dave davis: If I were Daniel I would delete your comment. There are millions of innocent people – including children – who would be in the path of that cloud. You can’t wish this on anyone. Your statement reflects a diseased mind. The worst case scenario is that this event leads to great numbers of deaths, no matter whose.

  • John

    I’ve done a bit more calcualation based on what is out there on the intertubes:

    Reactor 4 SFP: 2 MW decay heat load (Wikipedia). Assume 10^6 kg uranium. Specific heat of uranium: 120 J/kg/K.

    If all the heat goes into the uranium, then

    2 MW/10^6 kg ==> 2 W/kg = 2 J/kg/s ==> 1 K/minute

    If the fuel rods are intact, but not in contact with water, then maybe the heat does not all go into the uranium. But suppose even a tenth of the heat goes into the uranium, that’s still 140 K increase per day! If there was no flow to the SFP in reactor 4, it is hardly surprising that it went dry (according to the NRC on Thursday).

    The heat of vaporization of water is 2.2 kJ/kg, and there are 10^6 kg of water, approximately. So we need 2.2 GJ of energy, and we have a heat load of 2 MW, meaning that once the pool reaches boiling, it takes on the order of a thousand seconds to boil off. Not long. You need water to keep flowing. I see no indication anywhere, in any report, that they have gotten a kiloton of water into the pool.

    If the pool is dry, the temperature in SFP #4 is going up by on the order of a hundred to a thousand degrees Kelvin a day, depending on how, if at all, heat gets out of the pool. It’s been a few days – let’s assume that the temperature was 100 C when the water boiled off, and that was on Wednesday. The temperature is now several hundred degrees C, and when it hits 1100 C the uranium will melt, not long before the steel does (1400 C). This means the uranium will melt, pool, and possibly go critical as early as a week from now, maybe sooner, maybe later unless they get cooling water – a kiloton of it – to the pool.

    It is really hard to believe that this has not already occurred. The good news is that there was no explosive release of radiation yet. But has the pool gone critical? Is there a uranium/iron/fission byproduct soup at the bottom of it?

    Would someone please tell us what is going on? The radiation at the plant gate continues to increase exponentially.

  • dave chmberlin

    I appreciate your analysis John. One point I would like to add is these kinds of conversations are probably best kept on a science blog, the poor folks in Tokyo are almost in full panic mode already. Japan is giving a mixed messege to their people. On the one hand the power company is painting a rosy picture but the impact of the Emporer addressing the public for the first time telling them to be deeply worried really shook the people up. I guess what I am saying is maybe it is best that the public recieve all the details later. As long as the people in charge are not deluding themselves and give the general population enough warning of what is coming, that may be best. I have another concern. If one reactor has fuel that has reached critical how in the hell are they going to manually control the other reactors? Robots can’t do it. Hopefully a better management team is now in charge.

  • John

    I should probably shut up at this point, you are right, dave chamberlin. I am sure those in charge know full well what is happened or will happen, and the good news is that it does not seem that explosive release of radiation from #4 has occurred. In that sense maybe it really is stable…

    This also made me feel a little better: http://atomicinsights.blogspot.com/2011/03/stop-worrying-about-spent-fuel-pool.html

    Maybe the zirconium cladding is intact?

  • dave chamberlin

    Well things are getting blowed up better in other parts of the world so the reactors have become second page news. That is from an old SCTV skit, “I like how dat blowed up, it blowed up real good. ”
    Two quotes to leave you with, the first from Leo Szilard who first patented the idea of a nuclear reactor and wrote the letter which he had his more famous friend Albert Einstein co sign which directly led to the Manhatten Project.

    The three Stages of truth for scientists
    1) It’s not true
    2)If it’s not true, it’s not very important
    3) We knew it all along

    The second from Peewee Herman

    There are some things you wouldn’t understand, there are some things you couldn’t understand, and there are some things you shouldn’t understand. HEHEHEHEHEHE

  • John

    The “US Army” is helping out at reactor 4, according to TEPCO. They read 0.1 Sv/h n the inland side of reactor 4, and four times that at reactor 3.

  • dave chamberlin

    The poor Japanese people are not being given the truth and it is scaring them worse than if they were. The news sounds a lot like war propaganda when your side is losing. A radiation leak from reactor three that forced the work force to retreat from on 3/21 is now being called “puffs of grey smoke”. On the one hand the news is the reactors are “verging on stability” (US report) or have been stabilized (Japan report) and on the other hand Kyodo News (the Japanese equivalent of the Associated Press) says reactor 4′s spent fuel pool is “feared to have renewed nuclear chain reaction.”

    If the crane and concrete pumping truck now in front of reactor 4 are doing what I think they are doing, continuously pumping water mixed with boron into this spent fuel pool, things should be OK. This is just my construction management speculation, I don’t know what they are doing. But no one knows because the news is scant and not to be trusted. The only reliable news is levels of radioactivity measured outside of the 18 mile concentric circle surrounding the plant. They have to give that information and even that you have to dig for.
    Just my opinion but if I were living in Tokyo I would be scared to death not from the facts but from way they have been presented.

    Kyodo News reports that Fufushima Nuclear Power plant was designed to withstand a tsunami of 5.7 meters but got hit by one of 14 meters. That is a 46 and a half foot high wall of water that hit that plant! Incredible.

  • Cody Wilson

    I’m sure they must be putting a great deal of containment rod material around the radioactive fuel rods to soak up the neutrons and prevent the water from evaporating, right?

    If a nuclear plant produces energy for such a long time after being turned off why isn’t that power used to cool the system as the first line backup?

  • John

    http://english.kyodonews.jp/news/2011/03/80539.html

    Words fail me, so I’ll only say this: NEUTRONS OVER A KILOMETER FROM THE PLANT??

  • dave chamberlin

    Congratulations to Daniel for accurately predicting what would happen. I was really really worried that the radiation would get so deadly at one plant that human control would not be possible at the others. The still isn’t talking about the eventual course of action that Daniel predicted way back on March 16th. They are going to entomb some if not all of these plants. This is why we trust the good folks at science blogs.

  • Pingback: Cómo funciona una central nuclear y por qué tiene que importarme. « Círculo Escéptico Argentino

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Cosmic Variance

Random samplings from a universe of ideas.

About Daniel Holz

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »