March 13, 2011

2nd Interview with My Dad, a Nuclear Engineer, about the Fukushima Daiichi Nuclear Power Plant Disaster in Japan

Posted by Evelyn Mervine

A recent photo of my Dad and one of his favorite trains– he is a high speed train buff.

Update: All the interviews are now available on a vimeo channel. Here’s the vimeo channel:

Update: Announcing Daily Updates from my Dad

Here is the audio file for today’s interview:

Here is a vimeo video of the interview:

Update: I have cleaned-up the original transcript.

Update: There is now a transcript for after the jump. Thank you, Chris!

Interview 2: Sunday Morning, March 13th, 2011
2 Days Since Tōhoku Earthquake and Tsunami
EM = Evelyn Mervine
MM = Mark Mervine
MM: Good morning.
EM: How are you, dad?
MM: Okay.
EM: Good. Are you ready for a second interview?
MM: I am.

EM:  Okay. Before we start on today’s interview, I just want to thank everyone who listened to yesterday’s interview. My dad and I are really happy that we could provide you with some basic information about nuclear power and also some specific information about the nuclear disaster in Japan. If you haven’t done so already, I encourage you to listen to yesterday’s interview. You can find it— with a full transcript— at my geology blog Georneys ( or you can find it on the Skepchick blog ( The purpose of today’s interview is for my dad to give an update on the situation in Japan, and also to answer some additional questions, including some questions that were sent in by people who listened to the first interview.

So, just to start off with, dad, could you just introduce yourself again, and very briefly describe some of your background in nuclear power. And I just want to mention that if you want to get a full description of my dad’s backgrounds, please listen to the interview from yesterday.

MM: Good morning. I graduated from the Naval Academy in 1981 and worked in the Navy nuclear power program. I worked at two different Navy nuclear power plants and was an instructor in the program. After seven years of active duty, I went into the Reserves and initially went to work for Wisconsin Electric, which at the time owned the point Beach Nuclear Plant, which is a Westinghouse two-unit plant in Two Rivers, Wisconsin. And after a few years there I went to work at Vermont Yankee, which is a boiling water reactor in Vernon, Vermont.

EM: Excellent. I think that’s enough for today. So, to start off with, could you please give us an update about what’s happening at the Fukushima nuclear power plant since you talked to us yesterday?

MM: Okay. Well, again, I have to rely on news, just like everyone else, either from reports from the internet, TEPCO [Tokyo Electric Power Company], their website, the International Atomic Energy Agency, and, of course, television. And what I’m able to piece together— I’m kind of doing an analysis of all the different reports— is, as we talked about yesterday, we have a serious problem at the Fukushima Nuclear Power Plant, Unit 1. And in taking some time to reflect on all the different reports after our conversation yesterday, it’s pretty clear that we’ve had a partial failure of the fuel rods in that reactor. And let me explain a little bit. So, as most everybody knows from the news now, there was an explosion at that plant yesterday, which destroyed the building surrounding the reactor, which is typically known as the auxiliary building[1]. What they were doing was they were venting pressure from the reactor into that building. And that steam also contained a mixture of hydrogen, which— when it interacted with the oxygen in the atmosphere— exploded.

Where would the hydrogen come from? Well, the fuel rods are – the fuel pellets, I should say— are encased in fuel rods which are made of zirconium. And zirconium, when it gets to approximately 2200 degrees Fahrenheit, will interact with water, or H2O, to form zirconium dioxide, and hydrogen is released. So, in order for there to be a significant amount of hydrogen, it’s pretty clear that at least a portion of the fuel had reached 2200 degrees, and we have zirconium oxide being formed and hydrogen being released.


Also, it has been reported that in the environment they’re able to detect cesium and iodine. Yesterday, I mentioned that when uranium fissions, it breaks apart into smaller elements and releases energy. A couple of the smaller elements that are formed are cesium and iodine. Normally, those would stay within the fuel rod, and the only way they would get out is if there was a failure of a fuel rod. That doesn’t mean that there was a complete failure, but— in conjunction with all the other things we know, the radiation readings, the fact that there’s cesium and iodine in the environment, the fact that we had hydrogen released— does indicate that we’ve got at least some fuel failure in that reactor.EM: So, does that mean that we’re in a meltdown situation? And, if so, can you please explain what a nuclear meltdown is?

MM: So, a meltdown, as it typically would be referred to, would be a complete meltdown of the reactor core. That’s probably not happening. In order for there to be hydrogen generated, then there was obviously some water. We know that they’ve been injecting seawater mixed with boron into that plant. So, there’s some water in there, and I would agree with most folks that a complete meltdown is probably not likely at this point. But again, it does appear that probably the upper part of the fuel was exposed, and some damage has occurred. And the release of iodine and cesium to the environment from those fuel rods has occurred.

EM: So yesterday we were mostly talking about the Fukushima Plant Number 1. And the news reports seem to be saying today that there are some additional reactors that are in trouble at Fukushima and perhaps other places. Do you have an update on that?

MM: So, if you recall yesterday, there are six nuclear reactors at the Fukushima 1 Site. Three of them were shut down for normal maintenance and had already cooled down substantially and are not an issue. Units 1, 2, and 3 were operating at the time of the earthquake and shut down automatically. What’s occurred in the last 24 hours is: at Unit 3, which is a newer plant and slightly larger than Unit 1, they have lost the normal shutdown cooling and emergency cooling systems, and they are also attempting to inject fire water [water sprayed from fire trucks], which I assume is seawater, and boron into that reactor as well. They are also saying that they’re going to need to or are venting pressure from that reactor, so again it does appear basically a very similar scenario to Unit 1, where they are going to be releasing steam. They probably had a partial uncover of that core [at Unit 3], and there probably is some fuel damage from that reactor [Unit 3] as well.

EM: Okay. But have they made progress, have they managed to get battery power and generators in there? It sounds like if they’re able to have some kind of cooling system, they’ve done that.

MM: It does sound like, even at the time that we spoke yesterday, that they had gotten power. The updates that I’ve seen indicate that they do have power at those sites, and that’s what they’re obviously using to pump the seawater and the boron into both of those reactors.

EM: Excellent. Another question I have for you is: yesterday there were reports that people were actually testing positive for radiation, and in the news I think there were people both over- and under-reacting to that. Can you give your perspective on that?

MM: So, it wasn’t 100% clear how many people, or whether these were workers from the plant or members of the public. Because they are releasing some radiation, even if there was no fuel failure, when they’re venting this steam from these reactors, there would be some small amounts of radioactivity. So, it would be possible for a worker from the plant to pick up some radioactive contamination from these particles. And of course they travel up into the atmosphere. They said generally the prevailing winds were taking it out over the ocean, but there may have been some members of the public before the evacuation that were in close proximity to the plant that may have had some of these particles fall on them from the atmosphere.

EM: Do you think that poses serious [radiation] exposure? I mean, there were some experts they were interviewing that said that it wasn’t really very bad, the level of exposure so far, do you think there could be any health problems from the exposure that’s happened?

MM: Hopefully not. Again, it’s very difficult to get exact details of what’s happening and what the actual readings are. But we know that the Japanese government has evacuated people approximately 20 kilometers from the plant. So, I would say that the concern for major health risk— assuming that the conditions at these reactors don’t get any worse— is probably very, very minimal.

EM: And presumably the people who are actually working there are wearing some kind of safety gear so that they’re minimizing their exposure?

MM: That would be correct.

EM: And also they were distributing iodine tablets to people as a precaution to help with radiation exposure, so hopefully that will reduce the exposure level as well, and I guess the cancer response to that level.

MM: So, let me explain that. So your thyroid will absorb iodine, and the purpose of the tablets is that you take those, and then your thiodine— I’m sorry— your thyroid absorbs that iodine. And then if there is radioactive iodine in the atmosphere from the nuclear power plant, if you’ve already taken the tablet, your thyroid has absorbed as much iodine as it can, and it won’t absorb the radioactive iodine. And that’s important because your thyroid is one of your more active glands, and if you can prevent that from absorbing any radioactive iodine that’s a real help in a situation like this.

EM: Excellent. So, the last question I want to ask you is something that I know you mentioned to me personally, is that many of the nuclear officials who are reporting on the nuclear disaster in Japan are using this so-called “safe language” when describing the disaster, and this is one of the keys to you that this situation might be more serious than at first they were revealing. What do you think this means? And also, you’re not currently in the nuclear power industry. Do you think that this enables you to speak a little more frankly about the situation?

MM: It’s really hard to determine whether information is being withheld or not. First off, in the media, I’ve just been kind of appalled at some of the reporting that I’ve seen.

EM: Me, too.

MM: I won’t mention the person or the network, but on a major news network, a so-called expert, who I watched last night, when was asked about the cesium, said cesium was used to control the reactor. Well, cesium is not used to control the reactor. Control rods are used to control the reactor. As I explained yesterday, boron can be injected to control the reactor. But cesium is a radioactive byproduct of uranium fissioning, and normally should not be in the reactor, or— I should say— not be in the reactor water; it should obviously be in the reactor fuel rods.

EM: It should not be in the atmosphere as well!

MM: It should not be in the atmosphere, but it’s not used to control the reactor. The other thing that was appalling to me was the pictures posted on the website of this news organization and shown on TV were of a pressurized water reactor, and this [Fukushima 1] was a boiling water reactor.

EM: Hah! That’s not even the right type of plant.

MM: Right. They’re similar, but they’re different, and if you’re going to be a quote “expert,” you need to get it right. Now with respect to public announcements, I think the biggest thing that I’ve seen is, they have this currently rated as a Category 4, which is one level below Three Mile Island. In my opinion, if we’ve got a partial core melt, and all— any, I think, engineer or scientist given all of the data that’s available, even as limited as it is, would conclude that here has been at least a partial core failure— then clearly this is in my opinion not less than Three Mile Island, it’s at least equal to. And the fact that we have multiple units at the same site involved, I would think really this is worse.

EM: Well, that’s good to know. Because people have been looking at that number and feeling relieved by it, but I think it’s too soon to really feel relief in this situation. They really need to get things under control.

MM: And I think the other thing to point out is, this is not something that’s going to go away tomorrow. This is going to be something for days. They’re going to— even if they’re able to get a significant amount of water in those containment buildings, it’s going to take days for these reactors to cool down.

EM: I wanted to ask you some questions that people had sent me either in comments or by email when I posted this interview yesterday. I was actually quite surprised at how many people listened to the first interview, and I’m very happy that we’re able to address some of their questions.

So, the first question I had from a reader was basically asking about the power, and they asked: “If the nuclear power plant is still generating steam after a shutdown, I assume that the steam is still turning the turbines. So why can’t or don’t they use the electricity that they’re generating to power the cooling pumps that they need?”

MM: Okay. Well, that’s a very good question. So, the turbines on these power plants are very large. And once the steam goes through these turbines, it goes into a condensing system, where water from a cooling tower or river or the ocean, which is much cooler, condenses the steam back into water, and then it’s pumped from there back into the reactor. So a couple things: first off, we had an automatic shutdown of the reactor and the control rods were inserted. So the heat that we’re talking about removing is not the full power heat. It’s the residual heat. Which is very substantial but not at the same level that’s required to turn the turbine.

The second thing is that since we don’t have any power, we don’t have any of the cool water to cool the steam, we don’t have any pumps to pump the water back into the reactor. So it would not be possible, in the situation that they were in, to continue generating electricity. The plant was shut down, there was no power, that wasn’t a possibility. There is an emergency system where they can use some of the steam from the reactor to turn a pump, so it’s a steam driven pump to pump water into the reactor, but that apparently failed.

EM: Okay. Well that’s good to know. And then a second reader actually had three questions. So I’ll ask those three questions. The first thing that he said is: “Your father mentioned the best-case scenario. What would he see as the worst case scenario? For example, could radioactivity possibly spread to Tokyo or even beyond Japan’s shores, to other parts of Asia?” or the Pacific, I guess.

MM: Okay, as far as a worst case scenario, as long as they’re able to continue to pump water and boron into these containment buildings and as long as they’re able to release the pressure in the containment buildings in small amounts then there should not be a lot of radiation released. With that being said, the radiation is going to go up into the atmosphere, and depending on which way the winds are blowing, it may be detectable as far away as Tokyo or other places. But the farther away you go, the more it’s going to disperse, and the levels will be much lower and again as long as the situation doesn’t get any worse, I would not expect any concern except for in the immediate vicinity of the plant.

EM: Okay, that’s excellent to know. The second question that this reader had is: “If your father were asked to advise on US energy policy, would he recommend that we continue building nuclear reactors?”
MM: That’s a good question. [Long pause] When we design nuclear reactors, and we design the safety systems for nuclear reactors, we calculate the probability of reactor accidents of the types that we’re seeing in Japan. And the systems have to be designed in such a way that that probability is extremely low. Clearly, what’s transpired here in Japan was beyond what was taken into account in design of the plants. And I think it has to be looked at— because if the probability of failure of a reactor is, you know, one in a million or one in a billion, the fact that we now have two, at the same time, at the same facility, probably calls some of those calculations into question. With that being said, these reactors are relatively old. The Unit 1 reactor is actually 40 years old. And the designs for nuclear power plants have been improved dramatically over the last 40 years, and the next generation that would probably be built [would] have a lot more passive safety systems that don’t require electricity and don’t require pumps.

EM: Isn’t that a problem in the US, for instance, that so many of our nuclear power plants are aging? And partly that’s maybe because of a fear of nuclear power— there hasn’t been a lot of motivation to build new ones— and so we’re relying on these older plants when really maybe we should have newer technology?

MM: Well, again, you know, I think you have to look at certain situations individually. What we had here was an 8.9 magnitude earthquake [later upgraded to 9.0 magnitude], which apparently the plants withstood and safety systems functioned correctly, the diesel generators came on, and everything was working as it should. Then we had a tsunami of anywhere from 20 to 30 foot waves. And the thing I think that has to be looked at is: is that possible for other power plants in the world, that if there was an earthquake and a subsequent tsunami, are any of those plants at risk?

EM: Okay. Well, even basic things. I mean, I’m not sure where the generators were located, but in a tsunami situation perhaps those should be located higher up on the building and not at ground level. Things like that maybe they could take into consideration when reviewing power plants that are located close to the ocean.

MM: Correct.

EM: All right, so a final question that we have is also from the same reader, Patrick: “Just out of curiosity, would nuclear reactors in US submarines have similar safety measures to the Fukushima plant in order to keep a core reactor from meltdown? Are there on a submarine additional power sources, some sort of containment unit, things like that?”

MM: All right. Well, I’m not going to be able to comment on the design of Navy nuclear reactors. The design of Navy nuclear reactors is classified. Let me just say that they are a different design than commercial nuclear power plants, and the Navy has never had a nuclear accident in all the years that they’ve been operating nuclear power plants. But the design I cannot speak to because it’s classified.

Q: All right. Thank  you very much, Dad, I think that’s all for today.

A: You’re welcome.

Q: Okay, I’ll talk to you later, bye.

[1] Actually, this building is called the “reactor building.” See Interview 3 for the correction and explanation.