I can't remember where I found the exact reference, but Arnie Gunderson mentions that it will take a long time in this interview:
http://fairewinds.com/content/gundersen-speaks-chris-martenson-current-status-fukushima-part-i
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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.
Chris Martenson: So what do they do, do you think?
Arnie Gundersen: I think they will be forced to build a building around the building and then, because you need heavy lifting cranes – cranes that lift a hundred and fifty tons, which are massive cranes, to put the put the nuclear fuel into canisters, which then can get removed. That is sort of what happened at TMI, but all of the fuel at TMI was still at the bottom of the vessel.
But it was a three-year process to get the molten fuel out of Three Mile Island – four years actually. So the problem here is that all of the cranes that do that have been destroyed, at least on units 1, 3, and 4. And you can’t do it in the air. It has to be done under water. So my guess is that they will have to build a building around the building to provide enough shielding and water, so that they can then go in and put this fuel into a heavy lift canister.
Chris Martenson: Okay, all right, I hadn’t considered that. That’s a great insight.
So let me summarize here – we have these four reactors, three of them have melted through – one of them is – Unit 4 – is probably one of the more dangerous ones in the sense that it is going to be years to build a building around it. It's going to be years until really the situation is contained. And in unit four though, we are still concerned that in the year or two or however it takes to build a building and really stabilize that, another aftershock could come along. Or in the case of Unit 3, if another aftershock comes along and the pressure vessel is full of water there’s a chance here that we could see other event. That this situation is not yet fully stabilized in the sense that there are still surprises to be found. It's surprising where the water shows up. There might still be some surprises left in how the building behaves or systems hold up or fail. What else would you add to that summary?
Arnie Gundersen: The groundwater. I am very concerned – I am hearing nothing about ground water monitoring. We know the ocean – we know there have been leaks into the ocean. I am not convinced that there are not cracks in the structures that are allowing this highly radioactive water to get into the groundwater. And I have been talking to people in Japan and my recommendation there is that they should build a moat all the way around the reactor, down to bedrock, which is sixty feet or twenty meters, and about four and a half feet wide, which is a meter and a half wide. And fill it with a material called Zeolite. It's a very good absorber of radioactive material and it would prevent the outward migration of any of this radiation. That’s not happening and I don’t understand why.
So now we look at the building and we look at stopping the heat and the radiation that is going upward, but this is an enormous amount of radioactive material in the soil right now. And one of the prefectures nearby had radioactive sewage sludge. Someone who watches our site is an executive at a sewage business and he said it's not uncommon after an earthquake for groundwater to infiltrate a sewage system and that frightened me a lot, because if the groundwater is already contaminated out in these prefectures it could be a serious problem that is receiving no attention right now.
