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TEPCO Confirms Partial Meltdown of No.2 and No.3 Reactors 209

blau writes with an article in NHK World. From the article "The operator of the crippled Fukushima Daiichi nuclear plant says findings show that fuel meltdowns may have occurred at the No.2 and No.3 reactors within days of the March 11th earthquake. But it says both reactors are now stable at relatively low temperatures." TEPCO is also now blaming the tsunami for most of the damage rather than the earthquake.
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TEPCO Confirms Partial Meltdown of No.2 and No.3 Reactors

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  • by pablo_max ( 626328 ) on Tuesday May 24, 2011 @02:31PM (#36230712)

    Relative to what? The sun?

    • Re: (Score:3, Interesting)

      by _0xd0ad ( 1974778 )

      Relative to what they'll eventually admit they were.

      Seriously, is anybody else getting sick of this constant down-playing the severity of the situation? I understand the idea that you don't immediately run to the worst-case scenario and cry that the sky's falling, but this is ridiculous.

      • Is it downplaying, or simply a lack of insight as to what's going on inside there?

        • by Mindcontrolled ( 1388007 ) on Tuesday May 24, 2011 @03:30PM (#36231434)
          Well, if you followed the discussion over at physicsforum.org, which is populated by quite a lot of nuclear engineers, it seemed to be relatively clear from the onset that the cores at 1-3 had at least partially melted down. Reported water levels left not much room for speculation there. TEPCO is not exactly known for playing it straight, so yeah, I would call that downplaying.
          • by jd ( 1658 ) <{moc.oohay} {ta} {kapimi}> on Tuesday May 24, 2011 @03:50PM (#36231698) Homepage Journal

            Yeah, that was fairly obvious. You don't need to be a nuclear scientist (just someone who knows what historical accidents have been significant, which ones haven't, and what made the difference) to realize that TEPCO weren't being honest, but it helps if you are to understand what they were being dishonest about.

            What bothers me, more than TEPCOs dishonesty (which, frankly, is only to be expected when a company relies on image as much or more than products), is the number of people here who went around marking those questioning TEPCO statements in previous discussions as trolls. Sorry, but the science doesn't leave much room for debate. It seemed to be mostly by pro-nuclear fanbois who failed to understand you could be ok with the technology but suspicious of the implementors. I hope they are now willing to admit their errors and apologise for their abuse of the moderation system.

            • by EQ ( 28372 )

              I hope they are now willing to admit their errors and apologise for their abuse of the moderation system.

              Come on, low 4 digit ID, did you forget we are on slashdot?

              • by jd ( 1658 )

                Everyone is entitled to one fantastical hope beyond any possibility of it actually coming to pass. For example, there are still people on Slashdot who hope to form relationships or understand the more obscure Doonesbury cartoons.

            • by Luyseyal ( 3154 )

              You could be ok with the technology but suspicious of the implementors.

              Finesse has been a quality seldom seen here. Here, let me feed a troll: That position is like supporting the death penalty in theory but thinking the criminal justice system is far too primitive to mete it out fairly.

              In the end, you have gawker and freerepublic and the moderates are completely drowned out by the mouth foam.


      • Like that time Tepco ran a geiger counter on a piece of material and found a radiation spike 10 million times above normal? Then they realized the person running it had only made a single test which turned out to be inaccurate [bbc.co.uk], and everyone laid into Tepco for inducing panic?

        There are more dangerous things in the world than not knowing exactly what is meant by "relatively low".
        • Yeah, so you double- and triple-check it. But at some point "looks like things have been worse than we'd previously thought" starts to sound suspiciously like "looks like things have been worse than we'd previously admitted".

          • But at some point "looks like things have been worse than we'd previously thought" starts to sound suspiciously like "looks like things have been worse than we'd previously admitted".

            Then you run into the possibility that you are wandering into conspiracy theory land. They might not be admitting things, but at the same time they might have had no clue either.

            • at the same time they might have had no clue either

              When all the real nuclear experts are joining with the armchair nuclear experts and saying "you know, there could very easily be a much bigger problem here than they're admitting to", the people who are actually supposed to be experts who are operating this particular nuclear power plant (and who we're sort of relying on to properly handle the situation and hopefully foresee and deal with its complications) don't really get to use ignorance as an excuse when everyone finds out "hey, apparently things were m

          • by gdshaw ( 1015745 )

            Like that time Tepco ran a geiger counter on a piece of material and found a radiation spike 10 million times above normal?

            Yeah, so you double- and triple-check it.

            No, at the radiation level that they thought they had measured, you run.

          • by SETIGuy ( 33768 )
            I could swear that back at the time of the explosions they were saying that the low coolant levels had resulted in core damage and probable fuel melting. Or was I just getting a bad translation? They were saying it in a language I don't speak. The bigger question is whether the melted fuel went through the bottom of the reactor vessel, as it appears to have done at reactor #1, or whether it is still contained in reactor vessel. They seem to be implying that it is contained in the reactor vessel without
      • by kannibal_klown ( 531544 ) on Tuesday May 24, 2011 @03:38PM (#36231556)

        It's on both sides of the fence.

        Some article came out shortly after stating that the radiation being emitted into the atmosphere was X% that of Chernobyl... when it was really 1/10th the percentage stated. You have people spreading panic and fear, as well as people saying "see this is why nuclear power is evil."

        Meanwhile you have people there saying "no alarm, nothing to see here" and later that day we find out something major happened or people were being burned by the radioactive water.

        So you have fear mongers and people trying to sweep it under the rug. It makes it very hard to get an accurate picture of what's going on.

      • by DarkOx ( 621550 )

        I have to agree you don't spend your time talking best case or worst case, you spend your time talking about the most likely case. I think its pretty clear TEPCO went best case on just about every issue.

        You see this often when companies face these sorts of disasters, somehow they think its better to keep having to revise. All that does is make them look they not only don't have control over the situation but don't even understand it. BP did with the spill, its only leaking 20K barrels, well ok it might b

      • by sjames ( 1099 )

        What downplaying? We've known about the partial melt for quite a while now. This is just confirmation.

        When the more panicky parts of the populace and media are imagining smouldering glow in the dark radioactive zombis and millions of bodies being bulldozed into a mass grave, I suppose simple facts do come off as downplaying.

    • They said "stable at relatively low temperatures." "Stable" for a reactor generally means 100C or lower. Higher than 100C, if a pipe bursts and you lose pressure, the water can flash into steam, exposing the core to air again - an unstable situation. At 100C, a pressure loss would drop the temperature below 100C, the water remains liquid, and the situation is stable (at least until the water boils off).

      100C is relatively low compared to the temps required to melt the fuel. But it's still hot enough t
      • by Mindcontrolled ( 1388007 ) on Tuesday May 24, 2011 @03:33PM (#36231482)
        If you look at their temp gauges over at the TEPCO website, this is definitely not the case here. Especially at unit 3 there are still temperatures over 200 ÂC and they do not really get them down, even with constantly increasing water injection rates. For some reason, they started borating the water again last week - wonder why that is, if recriticality is not even remotely possible, as by their statements.
        • by jd ( 1658 )

          The heat has to be caused by the level of neutrons striking fissile material. It's the only source of energy beyond the natural decay. Ergo, to reduce the heat is going to require absorbing neutrons. At 200'C, the water will turn to steam but the boron won't be doing anything, giving you a nice coating. It might do something, depends on what it's like inside.

          • Nope. Pure decay heat without criticality is mostly caused by decay of fission products - going via alpha/beta/gamma decay routes. For example 131I -> 131Xe + beta + gamma + antineutrino. Free neutrons are only involved in the fission itself - be it at the natural rate, which will not be influenced by boron, or by a chain reaction. If you inject boron, you at least suspect the possibility of a chain reaction going on.
    • Termal camera measurements, and instrumentation show that the temps inside the reactor pressure vessels are at 270 C max, bad because that means that still is coming radioactive steam from the damaged reactors, good since that means that even if most fuel has melted, it didn't became a bloob of molten fuel damaging even more the reactor pressure vessels, meaning that as bad has is has get up to now, we are not dealing with the fuel out in the open like in the case of the Chernobyl disaster. The submission w

  • by Andy Dodd ( 701 ) <atd7.cornell@edu> on Tuesday May 24, 2011 @02:35PM (#36230750) Homepage

    Many of the status reports from early on indicated a partial meltdown. (It was described as "fuel damage" - but that's meltdown).

    So how is this news? We already knew the fuel rods had suffered from partial melting/damage. It's almost a given when you see status reports indicating fuel with only partial water coverage.

    • by LWATCDR ( 28044 ) on Tuesday May 24, 2011 @02:50PM (#36230964) Homepage Journal

      You don't get it. It melted down. That means that no one can live in Japan ever again. Millions will die, This disaster makes the actual Earthquake and Tsunami seem like nothing!

    • Fuel damage is not necessarily meltdown. The story was that the fuel damage was damage to the zirkalloy cladding, which they hardly could deny after the hydrogen explosions. In a suffciently cooled environment, that means that your fuel pellets drop out of the rods and collect at the bottom of the RPV, but do not necessarily melt. So far, that was the official story regarding the damage. Given the water coverage data, I completely agree that melting was a given from the first days, they just did not admit i
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      In the initial days of the reactor problems, there was concern that some of the core in reactor #1 might not have been fully covered by water, and that some fuel damage may have resulted -- as in a part of it. The claim was that a relatively small fraction was affected before they restored cooling water levels to normal levels, and that the core, while damaged, was largely intact. The "news" over the last week is that the entire core was uncovered for hours (the gauges were not functioning properly under

      • by wrook ( 134116 )

        I'm replying to too many posts in this thread, but again I feel compelled to do it. I watched the TEPCO news reports on TV. I live in Japan and I speak Japanese. It's possible that I misunderstood some things because it is a technical subject and while I am fluent in Japanese, these things are difficult. But your account of the events do not mesh with my recollection at all. This is from memory, but I recall them originally claiming that a large portion of the core had been left exposed for 5 hours. A

      • by ModelX ( 182441 )

        ...and it provokes serious questions about the ability to monitor exactly what's going on inside a reactor during a crisis. If you couldn't reliably tell that the reactor was actually in the process of melting down, then how can you react to the situation appropriately? It's like having faulty instrument readings while you're trying to safely land a plane with no visibility. The TEPCO crew could be the best reactor operators in the world, but if they don't know what is going on in there, they would be thoroughly borked.

        The sad part of the story is that TEPCO crew apparently knew enough to figure out what was going on (whiteboard photos prove this), but officially they pretended they didn't know and simply omitted strongly suggestive datapoints from public releases. Only now, when enough isotopes have been blown around northern hemisphere that any interested scientist can sample the isotope ratio in the air and work back the numbers they slowly admit some truth, while still covering up what really exploded in reactor numbe

    • How did we get "confirms" from "may have"?
    • I was kind of wondering why the "probably was a tsunami" thing was news, honestly. I thought everyone knew that starting 2 months ago.

      This entire story seems like a repost of a repost.

    • by wrook ( 134116 )

      There are two things that are news here (albeit a little bit late). The first is the extent of the melting. There was always a question as to whether the fuel had melted or if only the cladding had melted. Early on a British scientist wrote an opinion that the data indicated that the fuel had melted completely. TEPCO responded saying that it was a possibility, but that the data could also support the situation where only the cladding had melted. When they finally were able to get inside the building of

  • Now blaming? (Score:5, Insightful)

    by ustolemyname ( 1301665 ) on Tuesday May 24, 2011 @02:38PM (#36230778)
    As I recall, the blame was on the tsunami since day one. Sure, there was a brief moment of "The earthquake may have been more responsible than initially thought" a few weeks back, but that didn't seem to amount to much.
    • I think you're correct. The earthquake knocked out the main power lines, so the power switched over to the generators, and then the tsunami knocked those out. After that, the battery backups could only last so long. The only thing worse would be if an asteroid hit 10 minutes later. A perfect storm of "oh, hell...."

  • by BBF_BBF ( 812493 ) on Tuesday May 24, 2011 @03:17PM (#36231258)
    Tepco is shifting blame AGAIN.

    The Tsunami knocked out the power, but if it knocked out the valve control systems and pumps, why didn't all three reactors melt down at the same time?
    How come they started overheating when their back up batteries ran out of power. With the first reactor's batteries failing earlier due to tsunami damage. Mere coincidence? I think not.

    http://en.wikipedia.org/wiki/Timeline_of_the_Fukushima_I_nuclear_accidents [wikipedia.org]

    The reason the reactors overheated and melted down was because power was not restored to the reactors' emergency cooling systems before their batteries ran down. If Tepco didn't try to handle everything internally for the first few days, they would have gotten power hooked up to the cooling systems much sooner. The Japanese Self Defense forces could have flown in some generators if requested and if they didn't have any I'm sure the US Military would have been glad to help out and airlift a few generators to help avoid a nuclear meltdown.

    The key is that Tepco didn't request any aid from outside sources till it was too late and was forced to by the Japanese government.

    From what I can see it's a case of ineptitude by Tepco employees that made this situation much worse than it should be been.
    • by Solandri ( 704621 ) on Tuesday May 24, 2011 @03:33PM (#36231488)

      The Tsunami knocked out the power, but if it knocked out the valve control systems and pumps, why didn't all three reactors melt down at the same time?

      Unit 1 is a 460 MW reactor. Units 2 and 3 are 784 MW reactors. They have totally different ratios of heat generated to cooling capacity. This is why you're seeing reports for unit 1 coming separately, while reports for units 2 and 3 are (generally) coming concurrently. (The rest of your stuff about TEPCO being negligent, I agree with.)

    • by EdZ ( 755139 )
      They did request outside aid. The problem was that the country, and especially the surrounding area, had just been hit with the largest earthquake in 1000 years followed by a tsunami bigger than the design maximum for every sea defence built on the east coast. There was no way to lay new power lines in the space of time available with the batter backup, especially when most of your construction equipment has been washed out to sea or upended inside a house, and the rest can't get anywhere because the roads
  • Since when is "may have" the same as "confirms" ?

    • by JSBiff ( 87824 )

      You must have loved the title on another recent Slashdot article, "Swiss to End Use of Nuclear Power", which despite the very conclusive sound of the title, was really about some people in the Swiss Government *talking* about trying to get the Swiss to stop using Nuclear Power. Nothing had at all been passed into law or set as official government policy yet.

      I've long since given up worrying about Slashdot titles. They're almost worthless, except to give you a general sense of what sort of topic you're deali

    • Since when is "may have" the same as "confirms" ?

      .. since reactors world wide are run by an industry lobby, that tries to give out as little bad news as possible.

      Let me translate:
      An accident may have occurred: We had an accident, but don't know how bad it is.
      This might affect civilians: If for sure will affect civilians, but hopefully not at a scale significant enough to change things.
      We are looking into the possibility of evacuations: My family is already out of here, but getting you out is too expensive.
      Nuclear energy is still the safest energ

  • As I've watched the news about Fukushima, I have wondered if by trying to avoid fuel meltdown, did they make matters *worse*?

    I admit, I really have limited knowledge about what went wrong or could have gone wrong. I'm definitely not a nuclear engineer.

    But, from the news, it seems like the biggest source of problems was caused by hydrogen explosions. The hydrogen explosions happened because steam from the cooling water, under high heat and pressure, interacted with the Zircalloy fuel cladding, which caused t

    • by h4rr4r ( 612664 )

      The problems are multiple.
      1. Is the containment vessel solid? Will this burn through?
      2. If the melted fuel gets hot enough to burn you will get radioactive smoke, and such into the air.
      3. You are reducing the shielding to nearby people, by removing water that would be in the way.
      4. If you made the wrong and not industry standard choice, do you go to jail?

      Probably lots of other issues as well.

      • 1. Is the containment vessel solid? Will this burn through?

        If the answer to that is "no, yes", then it isn't a containment vessel.

        2. If the melted fuel gets hot enough to burn you will get radioactive smoke, and such into the air.

        If it's exposed to oxygen, or the air, it isn't in a containment vessel, or you blew it open by putting water in.

        3. You are reducing the shielding to nearby people, by removing water that would be in the way.

        The water is not for shielding. The water is for cooling.

    • The problem is that it could melt through the earth into the water table. Imagine what would happen if something that hot and dirty melted its way into the water table... untold radioactive steam explosions would then ensue!

      • by h4rr4r ( 612664 )

        Yeah, no. It would have to burn though a huge amount of earth. Not gonna happen. If it got through the concrete slab that would be bad enough. Contaminated water would then seep into the water table and the water supply might be made undrinkable.

    • by EdZ ( 755139 )
      A pile of molten Corium is still pretty nasty, and something that definitely needs to be actively cooled. The problem then comes with the very high-risk strategy of, completely blind, trying to raise the core temperature enough to initiate a core melt, then drop the core melt temperate again before it becomes dangerous. You've got a window of maybe a minute in which to do so, with little in the way of feedback, and no time to run an accurate simulation. And you better damn well hope your jury-rigged pumps r
  • I am wondering how many people have died from this disaster and add the deaths due to Uranium Mining. And I would like to compare it to people who have died in Coal mining and coal power plant accidents.

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