March 20, 2011

9th Interview with My Dad, a Nuclear Engineer, about the Fukushima Daiichi Nuclear Power Plant Disaster in Japan

Posted by Evelyn Mervine

Update: Gerald has kindly hosted all of the new audio files. I will update all the audio links (some of which are broken) soon– tonight or tomorrow. DONE Meanwhile, you can listen to all the audio files on the new vimeo channel Brandon and I created. You can also listen to most of the interviews on Brad Go’s YouTube channel.

Here’s the vimeo channel:

Georneys Nuclear Engineer Dad Interview Series on vimeo

Brad Go’s YouTube channel: 
Here is the 9th interview I have conducted with my dad, a nuclear engineer. Please see the rest of the blog (sidebar) for previous interviews. Please keep sending questions and comments to georneysblog@gmail.com. You can also follow me on twitter @GeoEvelyn but please do not send questions via twitter.

In the interview today, we talked some about radioactivity and uranium isotopes. I actually study uranium-series isotope chemistry in rocks. A part of my PhD thesis research is using the decay of uranium-series isotopes found naturally in all rocks (at low, non-dangerous levels, in most cases) to determine ages of rocks and minerals. I am actually working on this chemistry today in lab. When I eventually return to blogging about geology, I promise to write more about my uranium-series research in geology.  For now, I though it would be good to talk briefly about uranium and its isotopes since this is relevant to nuclear power. My dad and I also discuss this topic in our interview. You can see my isotope discussion and some useful figures after the jump.

Because of work obligations, our next interview will not be posted until late tomorrow evening (EDT). 

Here is the audio link for today’s interview:

Here is today’s interview on vimeo: 
Please see the announcement page for more information about these interviews:

There is text on uranium and its isotopes after the jump. Please transcribe this interview if you have time and interest– just post a comment below so that others do not duplicate your effort.

Update: Thanks to Michelle, a transcript is now available after the jump.

What is an Isotope?
Most elements have more than one isotope. Isotopes are atoms that have the same number of protons but a different number of neutrons. For those of you who might be a little rusty on chemistry, protons and neutrons reside in the very small, densely-packed nucleus of an atom while electrons reside in orbitals around the nucleus. Electrons have negative charge, protons have positive charge, and neutrons have neutral charge. Electrons have very little mass while protons and electrons have about the same mass. 
Cartoon of an atom. Note that this cartoon is not to scale and the nucleus is very, very small. Cartoon taken from here.
Because electrons are charged and reside in the outer parts of the atom, they are responsible for the chemical properties of an atom. That is, the number and placement of electrons determines how an atom is able to interact with other atoms by forming chemical bonds. So, even though isotopes have different numbers of neutrons, because isotopes of an element have the same number of electrons, they behave in a chemically similar manner. 
Protons and neutrons, which reside in the nucleus of an atom, do not govern chemical properties. However, they do govern nuclear properties. Nuclear chemistry and physics is complex, but basically if you add or take away things from the nucleus– protons and neutrons and parts of these– you change the nuclear properties of the atom. If you just add or remove neutrons, you change from one isotope to another. If you add or remove protons, you change from one element to another.

Isotopes can affect the physical properties of atoms. Isotopes of an element have slightly different masses that can lead to small, but important, differences in the physical behavior of an element. A simple example is a glass of water that is allowed to evaporate.Water or H2O has two elements hydrogen (H) and oxygen (O). Hydrogen has two naturally-occurring isotopes (hydrogen-1 and hydrogen-2) while oxygen has three naturally-occurring isotopes (oxygen-16, oxygen-17, and oxygen-18).  After some time, water sitting in a glass will become isotopically heavy as lighter oxygen-16 and hydrogen-1 evaporate preferentially over heavier oxygen-17 , oxygen-18, and hydrogen-2. As Thorsten points out in a comment below (he caught a typo/error in the original post), there is also hydrogen-3. 
Uranium and its Isotopes:
Uranium always has 92 protons, but it can have different numbers of neutrons. Uranium has two main isotopes: uranium-238 and uranium-235. The number given in an isotope name is the number of protons + the number of neutrons. So, uranium-238 has 92 protons + 146 neutrons. Similarly, uranium-235 has 92 protons + 143 neutrons. There is also a very small amount of uranium-234 (92 protons, 142 neutrons) which is produced from the decay of uranium-238.
Almost all of the uranium in the world is uranium-238. The average, naturally-occurring distribution of uranium isotopes on Earth’s surface is as follows:
Uranium-238: 99.2745%
Uranium-235: 0.720%
Uranium-234: 0.0055%


Because uranium-235 is the fissionable isotope of uranium used in nuclear reactors, the uranium that is used in nuclear reactors is “enriched” uranium. As my dad mentioned, the uranium used in nuclear power plants generally has ~3% uranium-235, which is a significant increase over the ~0.7% uranium-235 found in nature. The uranium used in nuclear power plants must be artificially enriched in uranium-235 through complex processes that I won’t discuss here.
Radioactive Decay of Uranium-238 and Uranium-235:

Uranium-238 and uranium-235 are both radioactive. A radioactive atom is an atom that does not have a stable nucleus. Because its nucleus is not stable, a radioactive atom will eventually decay to a different atom that is stable. This decay occurs at a steady rate that depends on nuclear properties but which can be measured (and used to date rocks!). Some radioactive atoms just go through one decay because the first decay brings them to a stable nucleus. However, sometimes radioactive atoms have to decay through a whole series of other radioactive atoms until they finally reach an atom that is stable. This is the case with uranium-238 and uranium-235. Uranium-238 decays through a whole bunch of intermediate, also radioactive atoms until it reaches stable lead-206. Similarly, uranium-235 decays through a whole different bunch of intermediate, also radioactive atoms until it reaches stable lead-207.

Here is a figure showing the uranium-238 decay chain: 
Figure taken from Principles and Applications of Geochemistry by, Gunter Faure, 1998: pg.280. Click on the figure to view larger.
Types of Radioactive Decay: 
Uranium is affected by three types of radioactive decay. 
1. Beta Decay
In beta decay, a proton is converted to a neutron or vice-versa. There are actually three flavors of beta decay: 
netruon –> proton + a negative beta particle
proton –> neutron + a positive beta particle
proton + “captured” electron –> neutron 
A negative beta particle is like an electron. A positive beta particle is sort of like a positive electron. I am simplifying greatly, but that is the general idea behind beta decay. 
2. Alpha Decay: 
In alpha decay, an alpha particle is emitted from the nucleus. An alpha particle consists of two protons and neutrons and is thus identical to helium-4. 
3.Nuclear fission:
The nucleus breaks apart into two fragments, usually of unequal weight.
I hope that this explanation isn’t too simple for people. I just thought it would be good to go over isotopes and radioactive decay a little more since this is relevant to nuclear power and our interview today.

***********************
Transcript for Interview 9:

Q: Good afternoon, Dad.

A: Good afternoon.

Q: All right, we’re gonna continue with out interview series. My name is Evelyn
Mervine and this is the 9th in a series of interviews with my dad, Mark Mervine, who
is a nuclear engineer. If you would like to listen to any of the previous interviews,
you can find them on my geology blog, Georneys, which is G-E-O-R-N-E-Y-S.
Georneys.blogspot.com. And in today’s interview- sorry, before we get started, I’ve
been try to give the time and date so…. Today is the 20th of March and it’s currently
4PM Eastern Daylight Time.

And as I was saying, in today’s interview, there’s gonna be 3 parts – the first
part, my dad is going to give his usual update about what’s going on at Fukushima.
In the next part, in the previous interviews, my dad has promised that he would do a
little homework and talk a little bit more about radioactivity and radiation, so he
will do that. And then finally we’re gonna ask as many questions- I’m gonna ask as
many questions as I can and my dad will answer those. And then again, because we
are receiving so many emails, we can’t answer every single question. With that said,
Dad, would you like to start with your update?

A: OK. So just as a reminder, we’re talking about the Fukushima 1 nuclear power
plant in Japan. And this power plant actually consists of 6 boiling water reactors.
And the ones that we have been most concerned about is Units 1 through 4. Let me
just quickly give an update on Units 5 and 6. So as we indicated a couple days ago,
they have been able to get a diesel generator started at Unit 6 and run a cable, which
essentially is the equivalent of a long extension cord over to Unit 5, to be able to
begin to restore power to both of those units. They now have 2 diesel generators
up at Unit 6 and they are supplying power to Unit 5. And in both of those reactors,
they’ve been able to establish normal heat removal capabilities. And they’ve also-
the reports conflict a little bit – but either removed some panels from the reactor
building or drove some holes in the reactor building, but if there was a buildup of
hydrogen, they would allow it to escape before it became at a level that it would
be explosive. Given that they were able to restore power and cooling, and hoping
they don’t have any more issues with those diesel generators, that’s probably not a
concern and we should consider that those two units are stable. Another reminder,
those two units were shut down for maintenance at the time of the earthquake.

Units 1 through 3 were operating at the time of the earthquake, and Unit 4
was shut down. And all the fuel in Unit 4 had been moved to the spent fuel pool –
the entire core had been taken out, not just 1/3 of it, which is normally done for a
refueling outage. And the (?) there would be that they were doing some more
extensive repairs or inspections of the reactor vessel and they needed to remove all
of the fuel, but in any case, all of that fuel was moved to the spent fuel pool for Unit
4.

Over the past few days, I think most people are aware of, they’ve been
pumping seawater into reactors 1, 2 and 3 and maintaining a relatively low pressure
in those reactors, while venting steam. The reactor buildings of Units 1 and 3 were
severely damaged by hydrogen explosions, early- relatively early into this event.
There’s also been an explosion in Unit 2, but it was less significant and there is less
damage in the Unit 2 reactor building. And they have removed a couple of panels
from the Reactor 2 building, such that if there were more hydrogen to build up, it
would vent out and not become combustible or explosive. In Unit 4, even though
the reactor was not operating and all the fuel had been removed, there was a
buildup of hydrogen in the reactor building, which did cause an explosion and the
Unit 4 reactor building has been seriously damaged.

What’s been going on in the last 24 to 36 hours is it’s continued to inject
seawater into reactors 1, 2 and 3, and maintain pressure by venting. They put a
tremendous amount of water into the reactor 3 building by using fire equipment
and water cannons and in the past 24 hours, they’ve done the same with Unit 4. And
the purpose of doing that was to try to get water into the spent fuel pools at those
two buildings. They are also in the process of trying to run power from the grid to
those units and although I haven’t heard a lot about the progress today, the last
update from yesterday was that they had managed to bring that cable over to Units
1 and 2. And they’re in the process of- first, they’re gonna restore power to the
control room and then try to work their way through and see if they can get power
back to at least 1 cooling system. And they’re starting with Unit 2, because the
damage from the earthquake and from the explosions is less significant in Unit 2
and I think that’s a good strategy – when you’re trying to manage a situation like
this, where you have multiple things going on…they’ve got Units 5 and 6 stable, so
for the most part, from an operational perspective, that’s not something they have to
worry about in real-time. If they can restore power into Unit 2, which is the least
damaged, and get that one in a better condition, then they can focus on the
remaining problems at 1, 3 and 4.

So that’s the current status. Now we got a lot of questions and I have- I said
last time, and I copied you, Evelyn, that I would try to answer some questions about

radiation and radioactivity. I actually ended up talking a little bit about it in my
interview with Anthony. But I’ll just do a little bit of a recap. First off, I would
encourage people to take a look at Wikipedia. There’s actually been some great
information added in the past 24 hours, so if you take a look at Wikipedia for the
Fukushima 1 Nuclear accident, there’s a lot of good information there. And also, if
you do a search for “nuclear fission product”. There’s a good article there. And
they’re a little bit technical, and maybe a little bit hard to understand, but in
conjunction with what I’m about to explain, hopefully that will form a complete
picture for folks.

So we talked about this over the past week or so, but when fuel’s initially put
into the reactor, it’s Uranium. And it’s slightly enriched, so it’s approximately 96,
97% Uranium-238 and 3 or 4% Uranium-235. Now, Uranium is radioactive and-
naturally radioactive- and it decays by giving off alpha particles. But as I’ve talked
about, alpha particles don’t have a good penetrating range, and they can actually be
stopped by just a sheet of paper. So normally, alpha particles are not much of a
concern if you get them on you, because you’re outer layer of skin will stop them,
certainly your clothing will. But the big concern with alpha particles is if you ingest
them, or if they get in your eyes, so if you breathe them in or they’re on your hands
and you get them in your food, or if you get them in your eye, where your eye
doesn’t have the same protection your skin does, there’s concern about that. But
normally, a fuel rod, when it’s new, because the fuel is encased in zirconium, the
alpha particles won’t even penetrate that and you can really- other than you wanna
be wearing gloves, because you don’t want to damage the fuel or scratch it – you can
actually handle that without any concern. Once it’s in the reactor, though, it’s a
different story. So Uranium-235 will absorb a neutron and fission and break apart.
And when it does, it forms another- a number of, what we call, fission products. And
that’s where that article on Wikipedia comes in really handy if you wanna get into a
little bit of detail of what the different fission products are. But the most significant
ones that we talk about from a human health perspective are Iodine, Caesium,
Strontium. In particular, the reason that those three are significant is iodine can be
absorbed by your thyroid and your thyroid is one of your more active glands. So if
you get a lot of radioactive iodine in there is bad because radiation, or radioactivity
on your glands would have a tendency to cause more cell damage than, say you got
something on your skin, where the outer couple layers of your skin are normally
dead, so on your skin, it’s not gonna have that much of an impact. The two others,
Strontium and Caesium also replace what’s naturally in your body. So Strontium
will be absorbed by your body, similar to calcium. And so it gets into your bones
and bone marrow. And then Caesium is a lot like potassium to your body, and we all
know that we have a lot of potassium in our bodies, so the Caesium will be absorbed
instead of the potassium. So we talk about those a lot. And that’s why it’s a concern
when these things get into the environment. So I thought about the (?) particulates
that would be found in Uranium. The other thing that happens in nuclear fuel,

which we talked about is, the Uranium-238 does not fission, but it will also absorb a
neutron. It just doesn’t spit apart, it becomes Plutonium-230- I’m sorry, it becomes
Uranium-239. And after a couple decays, it becomes Plutonium-239. And
Plutonium has a very long half-life and will stay in the environment for a long period
of time and again, you have the decay that was- of Plutonium that would be very
dangerous to human health if it was ingested.

Q: And Dad, just to interject, that’s because it decays more quickly than the
Uranium? Is that why it’s more hazardous?

A: Well, it actually- for a given quantity, it has a very long half-life, which means it
actually decays less quickly.

Q: OK, I wasn’t sure what the decay rate was.

A: But if it becomes airborne or gets onto, y’know, food that you might ingest and it
gets into your body, then that’s problematic. So just like it would be problematic to
get Uranium in your body as well, because it’s an alpha-omitter and externally, your
skin is a good shield, but internally, you don’t have that skin, so it’ll get into your
lungs, your stomach, your intestines, those types of things.

Now, the fission product that we talked about, the Caesium and Iodine and
Strontium also are radioactive and they decay. And they decay by giving off a beta
particle. Again, external to your body, beta particles penetrate a little bit farther
than alpha particles, but again, they’re not as much of a concern outside the body,
it’s: “did I get it in my eye?” “Did I get it in my mouth?” “Did I breathe it in?” That’s
more of a concern. Or if it gets into the food chain, “did I ingest it because it was in
the food chain?” So the other type of radiation that we talk about are the gamma, or
the gamma rays, which are very, very similar to x-rays. The gamma radiation that
would be coming from the plant is not much of a concern except for at the plant,
because the farther you get away from it, the lower the levels. So certainly if you’re
outside of the 30 kilometer zone, the gamma radiation from the plant is not a
concern. Now, it is true that some of these particles that decay- and I mention ones
that give off alpha particles and beta particles, some of them will give off a gamma
particle, and again, if that gets inside of you, in a significant quantity, it won’t be
good for you because it’s inside your body. And could be damaging cells inside your
body. But the gamma radiation, people have seen, oh the levels at the plant are so
many millirems or other units, and that’s really not a concern to the general public,
the gamma radiation.

Q: That’s just close to the plant, that that’s a concern?

A: It would be at the plant itself or within- I don’t know what the levels are today,
but yesterday, it was reported that the levels at the plant boundary were 1 to 2
millirem per hour. That’s actually now fairly low, compared to what it’s been and
if you were to just go a little bit farther away from the plant boundary, it would
probably be almost undetectable from the gamma radiation.

Q: And that’s important because I know there’s been a lot of panic in the news about
your clothing doesn’t protect you from gamma radiation, as we said, but we’re not
actually gonna get that radiation unless you’re close to the plant, right?

A: Right, so that’s a concern for the workers at the plant. But for the general public,
the bigger concern is the alpha and beta emitters. So the fission products that were
in the fuel, but now may have gone into the environment. I shouldn’t say may have
gotten into the environment, I think it’s been shown that they have gone into the
environment. And the key is what is the amount, or the quantities, that have gotten
into the environment and if they’re at a level that would be dangerous or not. So
I don’t know if that’s cleared things up anymore. Again, I would refer people to a
couple of these articles, in conjunction to the explanations we’ve given, so it’ll form a
good picture.

Q: Sure, and I just wanna say something quickly that I think maybe isn’t clear. I
actually- for my thesis research, I actually study the uranium decay chain in rocks.
I don’t work with anything that’s super-radioactive, but I do study these things
in very trace quantities in rocks. And I know that we’ve been talking a lot about
Uranium being enriched and maybe some people don’t understand what that means.
And basically, in nature- and I actually just looked up on the table with nuclides,
and I’ll put a link to this table on the blog – in nature, on average, it varies a little
bit in the environments, the Uranium-238 isotope is normally about 99.27% and
the Uranium-235 is normally about .72% and so when you say that you have 2 to
3% of Uranium-235, that means that you’ve enriched it from that natural isotopic
distribution. So I just don’t know if we said that very clearly, so I just wanted to add
that.

A: Correct and that takes a lot of technology. It’s done in stages using (???) fusion,
so Uranium is actually converted to a gas and goes through a series of stages and

membranes, which is the way that we increase- not gonna go into a lot of detail,
that’s the way that we increase a percentage of Uranium-235 to the percentage of
Uranium-238.

Q: Anyway, I just wanted to make that clear, and this is something that I do study,
so I know a little bit about it, unlike most nuclear power, which I have to rely on my
father for. And I just wanna ask a question, now, before I move on to the general
questions, that I know many people are concerned about in Japan. There’s been
quite a bit of concern about the food supply in Japan and there have been reports –
some people have sent me questions – there are people very worried about whether
or not it is safe to consume food, in particular things like milk and fresh produce.
Can you comment on that? Is the food source at all contaminated with radiation?

A: Radioactivity.

Q: Radioactivity, sorry.

A: Well, there have been reports in the past day or so that they were able to detect
some of these fission products – so Iodine, Caesium – in some spinach and milk and
very, very trace amounts in the water in Tokyo. In the reports that I saw, I didn’t see
any report on what the levels are. And honestly, I personally don’t know what the
allowable limits are in Japan. So I don’t know if these- in the spinach and the milk –
whether these were below the allowable limit or above the allowable limit.

Q: Has the Japanese government made a statement on that at all, do you know?

A: They have, but I haven’t actually seen anything specifically.

Q: I just wanted to see if you knew.

A: So the answer is, it is something that people should be concerned about. But I
don’t think it’s something that people should be panicked about. And I think we
talked about this, either with yourself or with Anthony. That we’re getting more
organized, we’re getting more monitoring teams on the ground, to be able to take
more samples on a reoccurring basis. And I think that clearly, you’re gonna find
some detectable levels of these fission products in the countryside and in the food
chain. The question is, is it a level that is a concern? And hopefully with the
exception of the immediate area surrounding the plant, the answer will be no. And
we talked about that, for sure, I think a couple days ago – that definitely in the

immediate area around the plant, we’re gonna have to do a lot of sampling to ensure
that we don’t have any concern there. But the farther away you get – we’ve been
vary fortunately during the worst of the releases during this event, that the winds
were blowing from the west to the east and carrying the vast majority of these
particles out over the ocean. But some obviously did go inland and the question
now is what is the level? I think people have to be rational. All food has all kinds of
bad stuff in it all the time. Bacteria, fertilizer, I mean all kinds of stuff, and the key is
the levels are normally low, so it’s not anything that’s a hazard to human health. I
think it’s the case here, that as long as we do sampling and we’re sure that we’re not
exceeding any limits, that we shouldn’t panic. We should be concerned, but we
shouldn’t panic. And we’ll have to have a little faith in the people that are doing the
surveys and the government, that they’re gonna keep the food chain safe.
Obviously, they are doing sampling or they wouldn’t have determined that there
was these particles in the spinach and in the milk. So I think that’s a good thing, in
that the sampling is happening. I think it’s also good – although personally, I don’t
know know what the levels are – that they were transparent and they made the
announcement. And they have announced also that very, very low levels were
found in the water in Tokyo, but nothing to be concerned about.

Q: Well, that’s good and I think they should be concerned and as a- I just wanna
echo something that you said yesterday in your call with Anthony, that the nuclear
power industry is obviously concerned about the radiation and radioactivity and
you said sometimes in power plants, they do such a good job of shielding, that
actually the levels at the power plant are lower than in nature, I found that very
interesting that you said that. So they are aware of this and they’re used to dealing
with this, so hopefully they will continue to be more transparent and let people
know about what they should be concerned about and what they should not be
concerned about.

OK, do you have anything else to say before I go on to some questions, Dad?

A: No, I’ll take some questions.

Q: OK, so again, we can’t answer every question, but we’ll go on ahead with the
ones we’ve decided to answer today and we have answered many questions, so if
you don’t see an answer to your question, check out the previous interviews, plus
the interview with Anthony. There are transcripts up for everything, and actually,-
except for the interview with Anthony, but that transcript should hopefully be up
soon.

OK, the first question is… I know we’ve talked a little about this, but I think
some people are still confused. Can you explain a little bit more about how control
rods work?

A: Sort of, OK. So in a boiling water reactor, the control rods are shaped like a cross.
And there’ll be fuel rods that are put together into what’s called a fuel element,
or fuel assembly. Usually 7 by 7, so 49 fuel rods, although that can vary with the
reactor or the design, those are put together in an assembly and the control rods
will go up between 4 of those. So the fuel rods- the fuel rods are obviously spaced
a little bit and the control rod will go up between 4 of those. Control rod has boron
in it and boron will absorb a neutron, but it won’t fission. And we talked a couple
days ago about a reactor has to be self-sustaining, or order to be critical, in order
to generate enough energy to be a power plant. And if we don’t have – or I should
say, if the amount of, what we call, thermal neutrons in the core isn’t a constant
and it’s going down, then the power will go down. If it’s a little bit above constant,
then power will go up. And so what you do with the control rods is if you want to
increase power, you’ll move the control rods out of the core a little bit. And that will
– just because of the surface area of the control rods, by taking them out of the core
a little bit, then less neutrons will be absorbed in the control rods and more will be
available to fission with the fuel. And that will cause power to go up and a little bit
more energy to be generated. The opposite is true. If you wanna reduce power, you
can just move the control rods up into the core a little bit and – one of my references
is on a boiling water reactor, the control rods actually come up through the bottom
of the reactor vessel, up through the bottom of the core. So if you move them up
a little, then they’ll absorb more neutrons and cause power to go down. And then
of course, in the case of an automatic shutdown, or SCRAM, the control rods would
be fully inserted into the core. So all approximately 14 feet of the core would have
control rods in them, and then that would cause the reactor to go significantly sub-
critical and shut down. Does that explain what you were looking for?

Q: I hope so. I think that clears it up for me, hopefully that clears it up for some
listeners.

A: The key is, the control rod absorbs neutrons and if you have- if you don’t have
enough neutrons to keep a self-sustaining reaction, then power will go down. Or in
the case where you fully insert them, like on an automatic shutdown, you’ll cause a
large number of neutrons to be absorbed by the control rods and power will drop
dramatically and the reactor will go sub-critical.

Q: OK, I think that’s enough on that one. For the next question, this is another- I
think now we’re sort of clearing up some confusion from some people. Someone
was writing to me because I guess reading various sources on the internet, they
weren’t sure if at any point during the nuclear disaster, any of the fuel rods at any
of the reactors or any of the spent fuel pools were either or partially or completely
uncovered, meaning that they didn’t have any water on top of them. Can you
answer that question, or do you know?

A: So based on what we’ve seen happen, which is we’ve have hydrogen explosions
in Units 1, 2 and 3 and from the spent fuel pool of Unit 4, and the reports that we
have from the site, we do believe that part of the fuel rods have been uncovered at
reactors 1, 2 and 3 and also in the spent fuel pool at Unit 4. And why do we think
that? Well, we think that because in order to generate hydrogen, temperature had
to get beyond 2200 degrees Fahrenheit for the zirconium to interact with water and
form hydrogen. We had those explosions. The fact that they were able to detect
the fission products in the environment tells us that the fuel has to be damaged in
one or more of those reactors, otherwise, they would’ve been still encased in the
zirconium cladding. And then reports from the site itself have reported that they
think in Unit 2, once there was the explosion in Unit 3 and we lost cooling in Unit
2 for a period of time, they think the core there got uncovered twice. And they’ve
been trying to maintain with the seawater injection the cores in those three reactors
at least half-covered. What we don’t know is the extent of the fuel damage. And the-
probably the only way that will determine that is the same way it was at Three Mile
Island, that after years of cooling and having the radiation levels drop in the plant,
they’ll actually be able to either remove the head of the reactor or do a camera-
type inspection and determine how much of the fuel was actually damaged and how
severely damaged. As we talked about before, was it blistered, was it warped, or did
it really melt.

Q: Do you know what the extent of the damage was a Chernobyl?

A: Chernobyl was a completely different situation.

Q: Or not Chernobyl, sorry. I meant Three Mile Island.

A: Well, we know at – boy, it’s been a long time and I probably shouldn’t say without
going back and looking at some information, but we know there was definitely fuel
damage at Three Mile Island. I just don’t recall the extent of it.

Q: Alright, well, you have a homework assignment, as if you don’t already have
enough homework assignments.

A: Oh, thank you.

Q: My job is to deal with the internet, your job is to get the information. OK, so
I think we answered that question. Let’s go on. This is a question that I believe
you talked about with Anthony yesterday, but again, I don’t think everyone’s
heard that interview and there isn’t a transcript up yet, so um, this has come in
from many, many people. They wanna know why they just can’t build power
plants underground. And I guess they wanna know first, wouldn’t building them
underground provide good shielding and second, if that’s true, why don’t they put
them underground?

A: OK, well that’s an interesting question and it might not be obvious why that’s
probably not realistic. So obviously if they were underground and you could seal
that, that would provide a lot of shielding. And you could contain the radiation and
the radioactivity. But the problem is these power plants are huge. And usually
a power plant has two ratings. You have the Megawatt Thermal Rating and the
Megawatt Electric Rating. You need to probably have been an engineer or taken
thermodynamics to understand power cycle efficiencies, but it’s not possible today,
with any kind of power plant, whether it’s the engine in your car or a coal-power
plant or a nuclear power plant, to be 100% efficient. And typically, these plants are
somewhere on the order of 30 to 40% efficient, depending on the specific design of
the plant and the technology that we had at the time it was built. So what does that
mean? Well, that means that in the reactor, you have to generate approximately
three times more power than actually becomes electricity and leaves that plant. The
other approximately 60 to 70% has to be- is lost. That’s all of the power that that
ends up, in this case, ultimately ending up in the ocean. So one of the problems you
would have building a power plant underground is where do you get enough cooling
or enough water to remove the heat? When the steam comes through the turbine, a
good 60% of that power is still there and it has to be cooled to turn the steam back
into water and back into the power plant. And that just has to do with the principles
of thermodynamics, that with the technology we have today, we’re nowhere close
to being 100% efficient. And so we have a big cooling requirement, for any power
plant, not just a nuclear power plant. Whether it be gas or coal, they all need a lot of
cooling to condense the steam back into water. So that would be one concern.

The other concern, of course, is you gotta connect these power plants to the
grid, so you need a lot of space on-site for power lines and transmission lines, circuit
breakers, there’s usually a big, huge switch yard. And of course, you would have to
have a way to get the power out of wherever underground place this was, this

would not be an impossible thing to overcome, but again, I think it’s- in conjunction
with the need for cooling, you’d be talking about having to build a huge cavern,
which would probably make it, if not technically impossible, economically
impossible.

Q: OK, is that all you have to say on that question?

A: Well, I don’t know what else I can say, other than I’m trying to imagine a scenario
where you would have a big enough cavern, far enough down, and yet still have
access to enough water for cooling and those type of things and I just- I think it
would be difficult, if not impossible.

Q: Sounds like it would not be very economically feasible, either. OK. –

A: And you being the geologist can tell people there’s all kinds of issues with that,
in terms of trying to put something underground and having all the problems that
people have just building tunnels.

Q: Absolutely, it would be- y’know, if you think about what it takes to build just
something like the tunnel that goes from France to England and all the problems
they have with that, it would be an enormous task to try and put a power plant
underground and there’s also problems, I mean, just because something’s
underground doesn’t mean that it’s gonna be safe. A lot of our ground water, it’s
in permeable layers that are quite deep down and so you’d have a lot of concerns
about any kind of nuclear contamination getting into ground water. I mean, they
can try and line it and contain it, but just because it’s deep in the earth doesn’t mean
that it isn’t going to become a problem for us at the surface, I can definitely say that.

Alright, let’s move on to our last question for today. And this question is
again- actually all of these questions are ones that have come in from multiple
people, so it’s interesting that multiple people have the same questions. But this one
is….we’ve talked before about how if you add seawater to a nuclear power plant for
cooling, rather than using freshwater, that’s bad because seawater is more corrosive
and it causes damage. And also we know that the explosions that have happened
have caused damage. So the question is do you think any of the 6 nuclear power
plants at Fukushima can be reopened for power, or are they all going to have to be
decommissioned?

A: Well, I think it’s pretty safe to say that Units 1 through 4 will no longer be viable
power plants. And they’ll have to be decommissioned. Units 5 and 6 have not really
been damaged and, to my knowledge, they haven’t used seawater in either one

of those units. So it’s possible, depending on radiation levels and contamination
levels at the site, that Units 5 and 6 may be viable. The question is, y’know, given
what happened, with respect to the earthquake and the tsunami, are they viable
from that perspective? In other words, now that we know what we know, we can’t
allow it to happen again. So it may turn out that the location of the site is not viable
going forward. So I would think in theory, that Units 5 and 6 may be OK. I think the
question is, given what’s happened, would we want to use those 2 units again or
not. And that’s something that a bunch of- again, assuming that the radiation and
contamination levels would allow them to operate, would that be something where
we could modify the facility enough to have protection or not, I don’t know. That
would be something a lot of engineers and the Japanese government would have to
look at. My guess is probably not, but I can’t really say.

Q: Well, that’s probably- I’m sure those are questions that people, y’know, not just
involved in Japan, but people are asking that about power plants in geologically
active regions all over the world.

A: So 1 through 4, definitely not. 5 and 6, maybe, but I kinda doubt it, given that
this has turned out to be not a good location. But y’know, these power plants cost
billions of dollars to build and it may turn out that 5 and 6 are physically separate,
they are on the same site, but they’re some distance away, it might be possible
to build a big wall or some seawall or something to protect them, but again, that
would be something that I think the Japanese equivalent of the Nuclear Regulatory
Commission would have to take a look at. And we don’t know, specifically, how
badly damaged they were, in terms of their electrical systems. Apparently a lot less
damaged than the other ones. But we don’t know where all the systems are actually
located on the site and what they’re risk would be going forward.

Q: Alright, I think that that’s all for today.

A: OK.

Q: Do you have any last thoughts before we end?

A: I just wanna add one thing, we talked about radiation and radioactivity. And
I did see one news report that came out and corrected it, but even today, looking
in news reports, there was a lot of talk about Unit 3 today, because pressure was
building up in the containment, but that has stabilized out. They thought maybe
they would have to vent the containment there again, but they decided they didn’t
need to. And again, the news made a big deal of it, because that reactor has the mix
oxide fuel , which has both Uranium and Plutonium in it. As we discussed many,

many times, any fuel that’s been in a reactor has Plutonium in it.

Q: OK, Dad, that’s good for today.

A: OK.

Q: Take care, bye.

A: OK, bye.