Information, Radiation Leak Slowly From Japan
NEAL CONAN, host:
Just in the past 24 hours, a few headlines on the nuclear crisis in Japan. From the Associated Press: Situation very grave, Japan official says. BBC News: Japan Nuclear P.M. Naoto Kan signals maximum alert. And The Washington Post: Radiation levels at Japan nuclear plant reach new highs. Yet on Reuters: Japan says plutonium at plant not harmful levels. At the Christian Science Monitor: Japan says high seawater radiation levels no cause for alarm. And Bloomberg: Japan reactor crisis is becoming more stable, U.S. NRC (unintelligible).
Every day, we seem to hear both reports of progress and setbacks at Fukushima Dai-ichi.
Kathryn Higley is a leading expert on radiation and nuclear engineering. We've asked her back to answer your questions about what's going on at the Fukushima Dai-ichi nuclear plant.
Our phone number is 800-989-8255. Email, firstname.lastname@example.org. And you can join the conversation at our website. That's at npr.org. Click on TALK OF THE NATION.
Kathryn Higley joins us from a studio at Oregon State University, where she heads the university's Department of Nuclear Engineering and Radiation Health Physics.
And it's good of you to come back to be with us.
Dr. KATHRYN HIGLEY (Director, Nuclear Engineering and Radiation Health Physics Department, Oregon State University): Thank you so much.
CONAN: And every day, there seems to be a new setback. What do you know about what's going on?
Dr. HIGLEY: Well, I think that Japan suffered a horrible earthquake, the fourth largest ever, that they had a tremendous tsunami, and the facilities along the coastline were severely impacted. And you're dealing with reactor facilities that need to be stabilized and working under emergency conditions. So this is not normal sort of situation. Setbacks are to be expected.
CONAN: Yes. Maybe not to be expected, but we seemed to be getting contradictory information. We're told plutonium has been found in the soil. Then, we're told at a level that could have been found anywhere in the world.
Dr. HIGLEY: As I keep telling people, it's sort of a blessing and a curse in the nuclear industry and the radiation detection business that we can detect radioactive materials at extraordinarily low levels, which is a good thing, but it's also many orders of magnitude below where we would expect a threat.
And we know there is a global distribution of fission products and other products from weapons testing fallout. So it's not surprising that they're finding it, and it's also not surprising that there might be some in the vicinity of the plant from the plant itself.
CONAN: We're also told that there may be breaches in the containment boxes in some of these reactors and, indeed, in the pools where spent fuel rods are collected in some of the other reactors. There are six altogether there at this facility. And yet other people say this should calm down within time and not represent a real problem.
Dr. HIGLEY: Well, we do know that because there's cesium and iodine in the environment that they did have releases from these facilities, and that portions of the fuel were uncovered and were damaged. So we know that material got out.
Right now, it looks like what are called the volatiles are the ones that spread the farthest, but they pumped an enormous amount of water in to cool these facilities. And again, it shouldn't be surprising that within the basements and in the sumps that there are probably small amounts or potentially larger amounts of fuel particles that have been pushed through the system.
CONAN: Were - then there's the problem that over the weekend, Japan officials reported that radioactive water in one of the reactors, unit two, was 10 million times higher than normal. Just a few hours later, they came back and said: Oh, no. That was a mistake. It was only a hundred thousand times higher than normal.
First, it's a little alarming they can make a mistake of three orders of magnitude. And the other is, isn't a hundred thousand times above normal pretty scary too?
Dr. HIGLEY: Certainly, it is a level that would cause a considerable amount of concern, and when you're dealing with very, very high levels of radiation, you can have difficulties with instrumentation response. So, again, some of this is just sort of a natural - unfortunately, a natural occurrence in dealing with emergency situations.
CONAN: Then, we hear from the IAEA, the International Atomic Energy Agency, that three reactors there are in a meltdown state or partially melted down. We had a partial meltdown at Three Mile Island, and that scared a whole lot of people. Three of them at least partially melted down.
Dr. HIGLEY: Well, that is correct, and again, because we have cesium and iodine released into the environment, we do know that the fuel was damaged. And so you can describe that as a partial meltdown. It's like removing part of the tin can - although it's not tin, it's zirconium - around the fuel, and then the fuel can disintegrate and can fall into the bottom of the reactor vessel. So we do know that it's happened.
But what we have seen so far is that the containment and the reactor vessels have largely remained intact, and so the bulk of that material is still within the reactor facilities themselves.
CONAN: Let's get some questions from callers. And we'll begin with Eric(ph). And Eric's calling us from Boise.
ERIC (Caller): Thanks for taking my call.
ERIC: My question is about the endgame here. Are we - are they trying to stabilize the reactors and return them to service? And if not, why don't we give them the Chernobyl treatment, for lack of a better term, and just do something to kill them and seal them so they're no longer a problem. Thank you.
CONAN: The reactors at the - the reactor at Chernobyl, as memory serves, was buried in cement and boron.
Dr. HIGLEY: So he asked a very good question. And the first point was to stabilize them. And what they need to do is to put them in a condition where you don't have to worry about a new little nuclear reactor occurring at some point in time under any sort of cover. So what they want to do is remove as much of that contaminated sea water, put in fresh water. And they will have folks - individuals that have specialization in a field called criticality take a look at it and determine what's the best way to keep these reactors in an inactive state and then how to best go about putting some sort of cover or isolation.
But that's going to take some time. In the short term, it's cooling them and getting fresh, clean water into the facilities.
CONAN: And as far as we understand, there's no thought of restoring at least these three reactors to service. Is it all six?
Dr. HIGLEY: I believe, at this point, the discussion - when they started putting sea water into the units, at that point in time, they knew that they would be done in terms of their service. And I've certainly heard that discussion with the three. I've not heard it about the others.
CONAN: OK. Here's an email from Patrick(ph). Please have your guest explain the difference between radiation and radioactivity. Too many news outlets use those terms interchangeably.
Dr. HIGLEY: So things that are radioactive emit radiation, and that radiation can be alpha, beta, gamma, neutrons and a host of other particles. And we tend to, unfortunately, use the terms interchangeably.
CONAN: Why do we keep hearing different methods of measurement? We keep hearing about Becquerels and sieverts and all kinds of different things. Can't we agree on one?
Dr. HIGLEY: That would be nice, and the students that I teach would love it if that was the case. There are international units of measure - Becquerels, sieverts, grays. And then there are standard units of measure, which are the old historical ones which the U.S. uses, which are curies, rads, rems and Rankines. And we have to be bilingual, and, unfortunately, it's a great opportunity to mess up in your calculations when you convert back and forth.
CONAN: I could understand that there is the American - we use different wrenches, too, and international ones. But do all those things measure different things?
Dr. HIGLEY: When you talk about the amount of radioactive material, we speak in terms of activity, the number of decays that are occurring. And that's - units are either in curies and picocuries and femtocuries and megacuries or in Becquerels, which are expressed as the number of atoms disintegrating per second.
And then when we talk about the energy deposition, we use the terms rad or gray. And biological effect, it's sieverts and rem. And so it's a soup of terminology that takes a while to master, unfortunately.
CONAN: Let's go next to Jim(ph), and Jim's with us from Bloomfield Hills in Michigan.
JIM (Caller): Good afternoon. I got a question and a possible comment/solution. What engineering designs for nuclear plant alternative designs would have prevented the type of failure we saw in Japan? And then the solution I have is this for our dilemma here as a public policy issue. If we pass legislation that requires that the individual investor, not the taxpayer, be fully liable for the nuclear incident that may occur, we'll solve our public policy question.
Dr. HIGLEY: Well, I will speak to the issue of the plant design. Over the years, they have looked at improving the safety and operating circumstances for these reactors. And the push recently has been on what are called passively safe systems where you can remove a large number of pumps and design your facilities so that you actually don't need human intervention for some period of time, typically a few days, where gravity forces water into cores.
And there's a number of designs that are out there. There's some new novel the small modular reactor designs, which make the cores smaller and also in a safer configuration. And there's a lot of interest in pursuing these and particularly after what we've learned as we learn more about what's taking place in Japan.
CONAN: And even the designs that we have, the older design that the boiling water reactor there in Japan, and we have some of those in this country, too, the rate of those accidents has been very, very small. Nevertheless, when they happen, they are vivid and very, very scary. And a lot of people say, wait a minute. You could point to all kinds of accidents in coal mining and in gas extraction and gas explosions. And there is no method of developing energy that seems to be perfectly safe.
Dr. HIGLEY: That's absolutely true. And when you look at these facilities and you put in context, in Japan in particular, I believe the numbers of deaths related to the earthquake and the tsunami now stand at over 10,000, and there's another 16,000 or so missing. And I may have reversed those numbers. And when you look at the impacts from the plant, at this point, we know that some of the radiation workers received elevated exposures, but it doesn't appear that anything is life threatening. And that the (technical difficulty) the general public were moved back to limit their potential future cancer risk.
So the impacts in terms of human health at this point are relatively modest, particularly in terms of the scale of the devastation being wrought by the earthquake, by the tsunami.
CONAN: And that's not to mention the environmental effects of burning carbon fuels and what that may cause down the road. But we'll leave that for another day.
We're talking about the questions and answers about the fuel - the problems at the Japanese nuclear fuel nuclear plant at Fukushima and Dai-ichi. You're listening to TALK OF THE NATION from NPR News.
And let me reintroduce our guest. Kathryn Higley, the head of the Department of Nuclear Engineer and Radiation Health Physics at Oregon State University and director chair of the OSU Department of Nuclear Engineering and Radiation Health Physics.
Here's an email question. Could you please ask your guest about the new Chinese pellet bullet-designed reactors? Are they a viable solution?
Dr. HIGLEY: I don't know much about this particular design, unless you're talking about some of the prismatic fuel or some of the pebble beds. And, again, these are ones that are designed to run at higher temperatures and typically don't use water. So, there are certain advantages; they're more efficient and intrinsically presumed to be safer.
CONAN: Let's go to Doug(ph), and Doug's with us from Union City in California.
DOUG (Caller): Yes, I have a question about the Ukrainian suggestion of replacing water with tin as the coolant inside the reactor vessel.
DOUG: This would prevent hydrogen gas from forming by water reacting with zirconium that would essentially kill the reactor and end the release of water from the reactor.
CONAN: Did you say tin?
DOUG: Yes, the Ukrainians at Chernobyl, after they had put led on top of the reactor, they realized that tin would've been better. It's less toxic. But that - little pellets of tin could be inserted into the reactor. They would melt and form a liquid metal coolant inside the reactor vessel. I heard the Ukrainians are willing to fly people from Ukraine to Japan to consult on this solution.
CONAN: Kathryn Higley?
Dr. HIGLEY: So what I would expect is over the course of the next several months that there's going to be a number of different discussions about how best to stabilize the facilities. And as your guest pointed out, the first thing you want to do is to minimize concerns for additional hydrogen production. You want to drop that heat load, but also, you want to make sure that there's no potential for criticality. And so that's going to have to be addressed before anything else can happen.
CONAN: Doug, thanks very much for the call.
CONAN: What do you now envision - what do you think the worst-case scenario at this point is in terms of the future of those six reactors?
Dr. HIGLEY: I think that they'll have to stabilize them and probably entomb in some fashion. They will have to deal with some residual contamination at the plant site and determine how much of the surrounding countryside will have to be embargoed or have restricted access for some period of time.
CONAN: And is that going to be measured in square miles, tens of square miles, hundreds?
Dr. HIGLEY: That's going to be determined over the course of the next several months, and there will be people out there monitoring like crazy, determining the level of potential hazard.
CONAN: And then there are the broader political issues. You're a scientist, but there are broader political issues. Clearly, the future of nuclear power in Japan is going to be hotly debated, and this is going to be raised as an example as Three Mile Island and Chernobyl were in their time.
Dr. HIGLEY: I think that you're correct, that there will be a tremendous amount of debate. But Japan is one of these countries that doesn't have coal, oil, and so they need energy. And what they need is safe energy, so this is certainly going to be part of the discussion.
CONAN: Let's go to Kevin. Kevin with us from Raleigh.
KEVIN (Caller): Yes. I had a question about the health impact of thorium reactors versus the current uranium reactors we have. Is there any difference?
Dr. HIGLEY: There is some difference in terms of how the fuel works and some of the radiations from the fuels. But when the facilities are operated appropriately, the radiological impacts are negligible under all circumstances.
KEVIN: Even in the case of natural disasters which man can't control?
Dr. HIGLEY: Well, as I said, under normal circumstances. And it really depends on what sort of an accident that you're looking at in terms of this material potentially getting out into the environment. So it's not a simple question to address.
CONAN: Are there tradeoffs in design of these plants to say, well, we've protected against every conceivable, you know, contingency, but obviously there are contingencies that nobody thinks of.
Dr. HIGLEY: I think that you do your best in terms of designs to minimize impacts to the environment, to minimize impacts to human health, and you devise redundant safety features and redundancies upon redundancies. And, you know, in the case of a situation as in Japan, where you have an enormous natural disaster, these facilities still have functioned largely to maintain safety in terms of keeping the core intact and precluding the release of material. And that's really what you have to consider in designing these systems.
CONAN: Kathryn Higley, thank you again very much for your time. We appreciate it.
Dr. HIGLEY: Thank you.
CONAN: Kathryn Higley, department chair of Nuclear Engineering and Radiation Health Physics at Oregon State University, with us from a studio on the campus there.
NPR transcripts are created on a rush deadline by a contractor for NPR, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of NPR’s programming is the audio.