如果福岛的冰崖解冻会怎样?看看日本实验的风险

 　　JEFFREY BROWN: And we check in again with two people who've helped us keep up with the continuing crisis.

　　Arjun Makhijani is an engineer special -- engineer specializing in nuclear fusion 1.
　　He's the president of the Institute for Energy and Environmental Research. Kenji Kushida specializes in Japanese studies at Stanford University.
　　Welcome back to both of you.Arjun, first, let me start with you. How serious are these new revelations about the water contamination?
　　ARJUN MAKHIJANI, Institute for Energy and Environmental Research: Well, the last time we spoke 2, there were -- we talked about the leak and the radiation levels that could give a worker an annual radiation dose in 12 minutes.
　　Well, more recently, there have been reports that the radiation levels near another tank are 1,800 millisieverts per hour.
　　This is an extremely high level of radiation. A few hours basically constitutes a lethal 3 dose.
　　So now we're talking about radioactive contamination in these tanks, the liquid stored in these tanks, that are very highly radioactive.
　　And so these leaks are extremely problematic for the workers and for management.
　　JEFFREY BROWN: And is this something they just discovered, or what suddenly causes that much more serious amount of levels?
　　ARJUN MAKHIJANI: Well, the best I can understand from all the confusing information that is out there is the first measurement was done with an instrument that only went up to a hundred millisieverts and maxed out.
　　JEFFREY BROWN: Yes.
　　ARJUN MAKHIJANI: So, now they're making more measurements and they're finding there are more contaminated spots and apparently 4 more leaks.
　　So I'm not quite clear what the company knows when.
　　But the information is kind of dribbling 5 out.
　　And the government is clearly concerned that the situation is getting more out of control.
　　JEFFREY BROWN: Well, Kenji Kushida, you pick up on that, because there's the company and then there's the government.
　　Clearly, the government is stepping in with much more force now, right?
　　KENJI KUSHIDA, Stanford University: Yes, absolutely, because the next election in three years is going to definitely reflect their response on this nuclear issue, because they're essentially 6 a pro-nuclear party that just won a landslide 7 election.
　　And so if they can't credibly 8 manage the operator's rescue efforts --and the operator which clearly seems to be unable to deal with the worst parts of the situation -- then the government is on the hook.
　　JEFFREY BROWN: But, from the outside, it looks like this is taking a long time to get to even the kind of understanding of the contamination levels that -- never mind getting to a lot of the more serious work that still needs to be done.
　　What is the sense in Japan as far as you can tell about the levels of, I don't know, desperation or urgency there?
　　KENJI KUSHIDA: Yes.Well, similar to what we said last time, the operator's reputation and people's confidence in it, which was already at an all-time low, is now even lower.
　　And after the government essentially de facto nationalized the operator about a year ago and replaced top management, people hoped that the ability of the operator to deal with some of these problems would have been enhanced.
　　But some of the media reports coming from Japan are saying things like subcontractors are leaking information that --literally leaking information that the tanks, thousand or tanks that they put together, in great haste, under severe cost pressure from TEPCO, which was -- before it was nationalized right after the disaster -- they were put together with bolts, but not welded together.
　　And so some of these subcontractors are saying, well, in the long run, even medium run, you would expect them to start springing leaks.
　　So, clearly, the operator hasn't been on top of the situation and people are getting fairly nervous about that.
　　JEFFREY BROWN: So, Arjun Makhijani, explain this idea of the ice wall. It sounds strange. How exactly would it work, and how much has it been tried before?
　　ARJUN MAKHIJANI: Well, I don't know that an ice wall like this has been tried before.
　　It's like building a dam underground, but with ice, by freezing all the poor water in the soil, all soil has -- so there's water coming in from uphill, through the side and going into the ocean, all underground.
　　It's an aquifer 9. Some of that water contacts the molten fuel and is becoming contaminated.
　　And they hope to build -- to freeze the soil, basically, with a giant freezing machine, just like your freezer at home, put cooling coils in the soil, lots and lots of them.
　　It takes an enormous amount of electricity and they would freeze it. Of course, it contains the water behind it like a dam, but eventually it's going to overtop the dam, as it did before.
　　They had another wall that they built. They chemically impregnated the soil to kind of solidify 10 it.
　　And that is what is overflowing 11 into the sea 300 tons a day. So...
　　JEFFREY BROWN: Well, so it has been done before, but not on this scale, you think? So is it an -- how would you describe it? Is it an experiment?
　　Is it a kind of stab at something?
　　ARJUN MAKHIJANI: It is an experiment.
　　JEFFREY BROWN: Yes.
　　ARJUN MAKHIJANI: And I think it's a risky 12 experiment, because if the power fails, you know, just like if your -- when the power goes out with your refrigerator, everything will de-freeze in -- defrost in the freezer.
　　So, if this ice melts suddenly and it's blocking an enormous amount of contaminated water behind it, then you have got a problem.
　　At the same time, you know, the tanks are themselves something of a threat, if there's another earthquake and this highly contaminated water gets into the ocean.
　　And so they have a got a very -- couple of very, very serious problems of containing the water.
　　JEFFREY BROWN: And then, Kenji Kushida, there is still, as we said, the long term here, which I heard talk about decades to decommission the plant, for example.
　　KENJI KUSHIDA: Yes.Some of the estimates are a minimum of 40 years to decommission the plant.
　　So this idea of frozen underground walls, a massive spending into innovative 13 infrastructure 14 projects can be a good thing.
　　But when it's the last line of defense 15 designed as a permanent solution to an almost seemingly intractable problem, I think the general public would be more comforted if they saw several options out there, rather than all the eggs being put into this potentially risky, unknown, and untested solution that may or may not work.
　　JEFFREY BROWN: You were talking about the politics earlier. Is there any uncertainty 16 as to the will to stay with this for the decades that you're talking about?
　　KENJI KUSHIDA: Well, there's no choice.
　　Given that the party is pro-nuclear and that they do not face elections for three years, their interest is definitely to do whatever possible, because if this gets truly out of hand in a greater sense than now, then they will be --and their heads will be on the chopping block in the next election, but they would like to avoid that.
　　That being said, it's not like there's a set of technical solutions that are easily possible here that can be chosen from.
　　So, in the very long term, they do need to try to stay in power, so you would expect them to put as many resources as possible.
　　And, as we do see, they are moving, but they need to much more quickly, as most general public would agree.
　　JEFFREY BROWN: All right, Kenji Kushida, Arjun Makhijani, thank you both again very much.
　　ARJUN MAKHIJANI: Thank you very much.
　　KENJI KUSHIDA: Thank you.