Arnie Gundersen: Lethal Levels of Radiation at Fukushima: What Are the Implications?

In the latest video on Fukushima (8/4/2011), Arnie Gundersen of Fairewinds Associates thinks 10-plus sieverts/hour radiation at the base of the exhaust duct is from cesium that has been released from the Containment Vessel of Reactor 1, condensed and accumulated at the bottom over time.

I don't necessarily agree with his hypothesis, but that's not what I was surprised when I saw the video. He says that the highly radioactive debris have been "bulldozed under", and when the debris are unearthed in the future we will see more high radiation spots.

I don't remember reading the news that the radioactive debris at the plant were ever actually buried. I remember one person who did say "Dig a hole, bury the debris so that the workers can work", Michio Ishikawa of the Japan Nuclear Technology Institute, a strong proponent of nuclear power who expressed a very pessimistic view of the TEPCO/government response to the Fukushima nuclear accident in late April.

Ishikawa also said the core had melted down and probably out of the RPV. That was officially admitted 2 weeks later. He also said a bridgehead must be built do the reactor, and forget about the turbine building. That also happened. Workers entered the reactor buildings, and they installed the heat exchangers for the Spent Fuel Pools (Reactors 2, 3, 4, and Reactor 1's heat exchanger has just been installed).

Is it possible that Ishikawa's suggestion on radioactive debris was also carried out? Or Is Gundersen simply mistaken? Or does he have some insider source?

Anyway, here's Mr. Gundersen's video:

Lethal Levels of Radiation at Fukushima: What Are the Implications? from Fairewinds Associates on Vimeo.

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Arnie Gundersen: Japanese Should Limit the Radiation, Not the Information

Arnie Gundersen's latest video on Fukushima.

Ex Japanese Nuclear Regulator Blames Radioactive Animal Feed on "Black Rain" from Fairewinds Associates on Vimeo.

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Arnie Gundersen: Hot Particles From Japan to Seattle Virtually Undetectable When Inhaled or Swallowed

Arnie Gundersen's latest video talks about "hot particles". He mentions a metallic taste experienced by some people in Japan and on the west coast and says it is a sign of radiation exposure.

Hot Particles From Japan to Seattle Virtually Undetectable when Inhaled or Swallowed from Fairewinds Associates on Vimeo.

To defend TEPCO somewhat, though, it was not TEPCO who doubled the estimate of the radioactive materials released from Fukushima I Nuclear Power Plant; it was the government agency, the Nuclear and Industrial Safety Agency.

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Arnie Gundersen: "On-and-Off Recriticality Possible in Reactor 3"

I was listening the podcast of the interview Arnie Gundersen gave to Chris Martenson the other day (in order to translate into Japanese) and noticed something I had missed when I skimmed through the transcript for my post.

Gundersen is saying that 10% of the fuel core of the Reactor 3 may be repeating a re-criticality, on and off:

"Unit 3 may not have melted through and that means that some of the fuel certainly is lying on the bottom, but it may not have melted through and some of the fuel may still look like fuel, although it is certainly brittle. And it's possible that when the fuel is in that configuration that you can get a re-criticality. It's also possible in any of the fuel pools, one, two, three, and four pools, that you could get a criticality, as well. So there’s been frequent enough high iodine indications to lead me to believe that either one of the four fuel pools or the Unit 3 reactor is in fact, every once in a while starting itself up and then it gets to a point where it gets so hot that it shuts itself down and it kind of cycles. It kind of breathes, if you will.

"I think it's a relatively significant amount – maybe a tenth of the nuclear reactor core starts back up and shuts back down and starts back up and shuts back down. And that’s an extra heat load; you are not prepared to get rid of one tenth of a nuclear reactor’s heat by pumping water in the top."

Hiroaki Koide of Kyoto University suspected an on-and-off recriticality in the Reactor 1 back in early April when TEPCO announced, supposedly erroneously, chlorine-38 was detected. Dr. Tetsuo Matsui of Tokyo University suspected recriticality in the Reactor 2 and/or the Reactor 4 Spent Fuel Pool. Gundersen suspects an on-and-off recriticality in the Reactor 3 (or any of the Spent Fuel Pools).

Below is the chart of iodine-131 detection at the Federal Office of Radiation Protection in Germany, plotting the CTBTO station data from around the world. Station 38 is Takasaki, Gunma Prefecture in Japan, 218 kilometers (135 miles) from Fukushima I Nuclear Power Plant. I always thought it was rather peculiar that there seemed to be periodic spikes in the amount of iodine-131 (also of cesium-137 but to a lesser degree) followed by a relatively calm, steady decline.

Could these spikes indicate what Gundersen is talking about? On-and-off recriticality?

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#Fukushima I Nuke Accident: Arnie Gundersen's Interview with Chris Martenson

(h/t Helios)

"Exclusive Arnie Gundersen Interview: The Dangers of Fukushima Are Worse and Longer-lived Than We Think"

Part 1

Part 2

Gundersen thinks the melted fuel is at the bottom of Containment Vessels in Reactor 1 and 2; for Reactor 3, he thinks there may be some left in the Reactor Pressure Vessel, causing a local, on-and-off criticality:

Arnie Gundersen: Yes, once the uranium melts into a blob at these low enrichments, four and five percent, it can’t make a new criticality. If criticality is occurring on the site - and there might be, because there is still iodine 131, which is a good indication - it is not coming from the Unit 1 core and it's not coming from the Unit 2 core, because those are both blobs at the bottom of the containment.

Chris Martenson: All right, so we have these blobs, they’ve somehow escaped the primary reactor pressure vessel, which is that big steel thing and now they are on the relatively flat floor of the containment – they concrete piece – and you say Unit 2 is roughly the same story as Unit 1 – where’s Unit 3 in this story?

Arnie Gundersen: Unit 3 may not have melted through and that means that some of the fuel certainly is lying on the bottom, but it may not have melted through and some of the fuel may still look like fuel, although it is certainly brittle. And it's possible that when the fuel is in that configuration that you can get a re-criticality. It's also possible in any of the fuel pools, one, two, three, and four pools, that you could get a criticality, as well. So there’s been frequent enough high iodine indications to lead me to believe that either one of the four fuel pools or the Unit 3 reactor is in fact, every once in a while starting itself up and then it gets to a point where it gets so hot that it shuts itself down and it kind of cycles. It kind of breathes, if you will.

The Fukushima accident is worse than Chernobil, Gundersen says:

Arnie Gundersen: Well, this event is – I have said it's worse than Chernobyl and I’ll stand by that. There was an enormous amount of radiation given out in the first two to three weeks of the event. And add the wind and blowing in-land. This could be – it could very well have brought the nation of Japan to its knees, I mean there is so much contamination that luckily wound up in the Pacific Ocean as compared to across the nation of Japan. It could have cut Japan in half. But now the winds have turned, so they are heading to the south toward Tokyo and now my concern and my advice to friends that if there is a severe aftershock and the Unit 4 building collapses, leave. We are well beyond where any science has ever gone at that point and nuclear fuel lying on the ground and getting hot is not a condition that anyone has ever analyzed.

So the plants, you will see them steaming and as summer goes on, you will see them steaming less, because the air is warmer, but it's not because they are not steaming, you just don’t see it. Because this event occurred in March and it was cool there, so you will see the steam a lot easier. Those plants are still omitting a lot of radiation. Nowhere near as much as on the first two weeks, but a lot of radiation: cesium, strontium, and mainly cesium and strontium – those are going to head south, whether or not there is a tropical hurricane. The wind is going to push it south this time and so the issue is not the total radiation you might measure with a Geiger counter in your hand, but hot particles.

And TEPCO and the Japanese government can't just give up and pour concrete over the mess, because the cores are just too hot:

Chris Martenson: So talk about -- realistically – I mean this is going to be months, years, whatever, it's going to take a long time. What do they do at this point, are they going to entomb these things, are they required to just keep dumping water on these things until they finally cool down, capturing water all the way through? Or is there some way that they can maybe just throw up their hands and just pour a bunch of concrete on it and call it a day?

Arnie Gundersen: I think eventually they may get to the point of throwing up their hands and pouring the concrete on. They can’t do that yet, because the cores are still too hot. So we are going to see the dance we’re in for another year or so, until the cores cool down. At that point, there’s not anywhere near as much decay heat and you probably could consider filling them with concrete and just letting sit there, like we have it at Chernobyl, as a giant mausoleum. That would work for units 1, 2, and 3. Unit 4 is still a problem, because again all the fuel is at the top and you can’t put the concrete at the top because you will collapse the building and it's so radioactive, you can’t lift the nuclear fuel out. I used to do this as a living and Unit 4 has me stumped.

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