Okay it says this hang out is live. I'm a little suspicious because I can usually tell on my little window here, if people are watching me or not, and I can't tell that anyone's watching me. So if anyone out there is actually on Google Hangout send me an email or let me know. All right so welcome to week two. Raynon. He is going to be joining us from his nuclear energy lab. Not that I don't let him come over here to my lab, but he's going to, he's going to to join us on Google Hangout. Now he's a nuclear engineer. We'll see if he actually has the ability to to log on or not. Any way rate, we're going to go through the questions again, just like we usually do. And okay, here's a good one. We're going to start right out with this one. It comes from Nate McKeeber and he says, could you explain the process behind artificial photosynthesis to make gas fuel? Okay, and I'm going to say a few words about that but not that much because we don't know that much about it. But also it seems to me that we can manipulate the organic photosynthesis of efficient organisms like algae to produce storable fuels so why do it synthetically? Okay so, so let me start with the, the first part of the question which is can you explain the process behind artificial photosynthesis. So there, theres, theres really two different things here. So there, there are a group of scientists who worked on something called solar fuels. And by that what they mean is, it's not necessarily photosynthesis, but the idea behind that one is, can I take photons, you know, energy that's coming in from sunlight. And rather than hit a photovoltaic cell and turn that elec to electricity, can I actually take that same energy, and on some some solid surface, use that energy to reduce CO2? So, so what does reduce CO2 means? That means add hydrogens to CO2 to so you're driving it from CO2, and pushing it back toward a fuel. So, so you're pushing it back toward methane, and then eventually back toward hydrocarbons. So that process works. But that is not artificial photosynthesis. Okay? That, that, that is solar fuels that's taking solar energy. That's taking photons up. >> Hi Steve. >> Arch can you hear me? I can hear you. Can you hear me? >> I think you're on mute. >> Okay. >> Turn, turn your speaker on. I can see George. >> It just says that I unmuted [INAUDIBLE] >> George, can you hear me? >> Yes. >> Okay, good. I cannot hear you. But, but I don't think I'm off, hold on. Talk. >> Hello Steve. >> Oh, good. Okay, so George, here's the trick. When you're, when, when you're talking, you have to mute the incoming voice, otherwise we get this echo when it pops back, okay? >> Okay, no worries. >> [SOUND] You got that? >> I got it, and so when I, when I'm talking, I'll mute my speaker. >> Yes, exactly. Because otherwise what happens is, I don't know if you can see this happening, but if, if you say anything, the camera will flip from, from you to me if, if one of us doesn't do that. >> Got it. So I just muted my microphone, is that now working properly? >> Working properly. >> Okay. >> Okay, so George, I already launched into the first question. But I'm going to stop talking about that for a minute because I want you to introduce yourself to the Office Hour participants. Okay. So say who you are, and what you work on. And then you and I are going to go through and answer some of these questions. >> Hi so my name is George Tynan. I I'm a Professor here at UC San Diego in department of mechanical neuro space engineering. My research is in nuclear fusion energy research for the most part. But I have a, a reasonable knowledge of nuclear fission which is the predominant nuclear energy source today. And some of its working familiarity with other energy technologies. And it's a topic I, I believe is extremely important and interesting, and hence my participation today. So thanks Steve. >> Okay, and George, if you look on the side of your little Google hangout thing, there, there should be a little button there that says Q and A. And if you click on that, then the questions open on the right hand side of your screen, and then you can see what questions, or highlighting the answer. >> Okay, let. Oh, I see it. All right. >> Okay, so. [CROSSTALK]. >> I'm up. >> Okay, good. So, so right now we're just finishing question number one, which is on artificial photosynthesis. And I was simply pointing out that there's a big group of people who work on something called solar fuels. Which is the conversion of photons, solar energy in, in, into some sort of fuel. But that's not truly artificial photosynthesis. And, and so the distinction that I want to make there, is, it's one thing to take photons, and reduce CO2 either into methane, or into some hydrocarbon fuel. And, and that's what we would call solar fuels. Still solar energy converting to a fuel. And that's different than photosynthesis because the process of photosynthesis and artificial photosynthesis, implies that you're taking CO2 and fitting it, in-, into by, by enzymatic means, into a, first a sugar, and then you can convert those sugars to everything else. And there are, so there are two very different groups that work on that. One of them is very much sort of solid state catalyst. In which you're using the photon to excite something in that catalyst in order to do that very energetically requiring the reaction of adding protons or hydrogen on, on the CO2. And then artificial photosynthesis is, is, is a whole string of electron transport, where you eventually make reduced NADP and then you use that reduced NADP, that also had reducing potential in it. But a biological reducing potential to again take, take CO2 and, and drive it to something that's more reduced. Meaning it has hydrogen on it, less oxidized. Okay. All right, so that's all were going to say about that one. You guys if you want to can send me specific questions and I will pass them on to people I know who work on, on through artificial photosynthesis. But George we're going to go to question number two here, because this is right up your ally. So I will click on and it'll pop up on the screen. Do you see it up there? How can we make nuclear fusion cheap? >> So the question is question two just sort of disappeared off my computer screen. Steve, could you repeat it for me please? >> Yes, I will, I will read it. It says, how could we make nuclear fusion, have to eventually engage it in civilian years? >> Okay. So I'll mute my speaker so that I don't get false words of feedback. Is that working Steve? >> Yep. >> Yeah? So in my view the, the challenge in front of fusion researchers at the moment is to first demonstrate significant energy production, or net energy gain, from a fusion reaction. For most of the history of fusion research, the, the experiments have actually consumed more energy than they've produced by fusion reactions. And obviously that's no way, no energy source. And so the first step in front us now is to demonstrate that one can in fact produce net energy gain from fusion reactions in some sort of engineered system. And there are experiments now underway trying to do that. One using very large lasers in the northern California and there's a similar facility under construction in, in Europe right now. And then secondly, there's an experiment under construction in France which who's stated goal is to produce about ten times more energy out than what went in in the first place. It's called the meter project. So step one is to demonstrate energy gain once, once it's done that and I would emphasize it has not yet been shown, but we think we're, we're building the facilities to do that now. Then the next step really gets more to your question of how can you do it cost effectively? And we, we've known for a long time that the next step in fusion reaction, fusion research will be develop all the systems that surround that that plasma to convert the heat, the energy release into usable form. And that's going to require the invention of new materials and some significant new nuclear engineering research. And I would say that work is just now really getting started in a serious way around the world. And that also has to succeed and so answering your question, you know, when is that going to happen. It's depends on how hard we try, of course, but also it depends on whether it really works. It's still an open research question, in my opinion. So I would say there's at least two clear steps, net energy gained demonstration. And then the design and construction and demonstration of a workable cost-effective reactor. >> You [CROSSTALK]. >> It's going to take some time. >> Yeah George can you just say a couple words? You know, a brief explanation on the experiment that is going on now in Europe. I, I, I'm sorry I don't remember the name of it. The giant tokamak or- >> ITER? >> Yeah. >> Sure ITER, if the students are interested, if you, it's spelled I-T-E-R. There's a, they have a great website iter.org. If you go there, you can see discussions about the physics of the experiment. What the devices could look like, the construction status, etcetera. But it's basically a very strong magnetic field that's arranged in a toroidal or doughnut-like shape. And then the fuel for the fusion is so hot that the atoms have been broken apart. And so the, the fuel is ionized. And so those charged particles are trapped on that magnetic field, and since the magnetic field is in a toroidal shape, they sort of race around the racetrack thousand, actually millions and billions of times. And every once in a while they'll collide together and fuse from hydrogen into helium. And then in so doing, they'll release a very significant amount of energy. And then that energy has to be converted into heat, and therefore into electricity. That kind of answer your question, Steve? >> Yeah, that's, that's absolutely great. Okay. So we're going to keep going down. There was another good nuclear energy question here that I though was really important for you to talk about, George. And, and I'll, I'll click it up here and then I'll read it to you. And it says, how could nuclear energy change developing and underdeveloped nations to help solve their energy issues? >> That's a multifaceted question. I'll, I'll do my best. Certainly nuclear energy is one of several energy sources that is essentially carbon free, or extremely low carbon intensity. And at the present time, it's mostly used to make electricity. And current reactor designs are, are best suited for producing electricity in a sort of a 24 hour a day, seven day a week, what has traditionally been called base load electricity generation. So I would say, it's probably likely over the next few decades that that will still be the main application of nuclear energy. Nuclear fission I will say emphasize, I'm talking about fission now, not fusion. Is base load electricity generation. Whether that, how, how, to what degree that occur, occurs as opposed to say an economy choosing to implement natural gas fired turbines, or solar, or wind based electricity generation. Is, is going to be a complicated decision. There will be certainly economic considerations that go, go into it. There'll be, frankly, whether the, the region, the, say, the nation state in considering implementing nuclear energy. There, there is a certain level of technical sophistication required to implement such a program safely. And so you gotta have the I would say human capital, and intellectual infrastructure in place to support it. And there's economic considerations nuclear energy is not cheap it's not unaffordable either but, you know, it's going to have to compete in the market against these other energy sources. And so whether it ends up being the, the right choice for, for particular developing nation, will be a complicated decision. I having said that, I know that there are you go to the International Atomic Energy Agency, which is a UN agency the IAEA. If you go to their website you can see listings of a number of developing economies that are seriously considering the construction of reactors. But again it will be a multi faceted decision. Nuclear is an excellent base load energy generation source. I would also state that as time goes on more and more of the human population is living in very large cities. Moving out of small rural regions into large cities of hundreds of thousands or even millions of people and those kinds of energy demand centers are very energy dense. And so nuclear might be a reasonable option for some of those places. Certainly not everywhere but for some. >> Yeah, so you say it's a complex equation. Whether you deploy it or not. >> Yes. >> And, and in my mind, it seems that one of the critical. Factors is you have a relatively scientifically sophisticated at least part of your population that could deal with. You know, the, the, I mean even if you bring in construction from outside to build these things. >> That's right. >> You still sort of need the locals to know how to run it. And one of the places that seems sort of uniquely positioned to do this is India. Where it, it's a very large county 1.2 billion people. 90% of it it is in real poverty. But the 10% that isn't in poverty is, is a pretty sophisticated group. You know the universities there, the training there in engineering is really good. And I notice that in India they do have several nuclear projects going on and that's like maybe one place where, where this could be deployed. Do you have any sort of thoughts on that? >> Well I mean your, your point is certainly well taken that India is a, a place that is, is planning on building a number of fission reactors. They also actually have active research programs under way in developing what are called next generation nuclear reactor technologies. That could, avoid some of the difficulties and challenges with existing reactor designs. So the Indians for example are looking at thorium-based reactor designs. And they actually have a research program developing those in India. We don't in the United States. And so if they're successful, you know, maybe a generation from now they could be licensing and exporting that technology to us. And China is another similar country that has a rapidly growing economy. A rapidly being ed, educated population. And has a very strong need for additional energy sources from renewable, fossil fuels, and from nuclear. Those are the two places that come to my mind most readily as, as place for nuclears to be considered. But there are also other places around the world as well. In the Middle East for example Saudi Arabia, United Arab Emirates and others are considering building reactors. Partially for electricity generation and partially frankly to run desal, desalination plants. So time will tell. But it's, it's, it's going to be a multi-faceted decision based upon economics. On the readiness of the economy and human capital to handle that technology. And what other resources are available and how much those resources cost. >> Okay so here's a, I think you actually kind of already answered this, but, but it's just a little more specific. And John McClintock says, do you have good communications with the DOE? And I assume he means the US Department of Energy there. Do you think that they were involved and engaged with fusion and new fission research and development. So maybe if you could just say a little bit. George about, you know what's going on in this country in terms of research in those two areas. You know, you mentioned China and India are. >> Certainly, in the fusion, research team, DOE is the place where that work occurs. So they, they own, essentially own that whole research area. And also in next generation fission reactors on DOE is primarily the, the place where that occurs. Although there's also I would say a lot of the more applied research in fission reactors in technology development occurs in the private sector. With some funding from the DOE for long term research. So I'd say fission it's sort of a partnership between the U.S. government and private entities. And fusion, it's entirely owned by the U.S. Department of Energy. >> Yeah, that, that doesn't surprise me at all. Although the Europeans in, in fusion are, are also heavily involved right? >> Ab absolutely I mean I, I only addressed who was in the game in the United States. I mean the European fusion program frankly is significantly larger than that of the U.S. now. And then there's also very significant activities going on in Japan, South Korean and China, India. And to some extent in Russia as well. >> Okay here's one that comes in from one of the students here in and he's actually a San Diego State University, Mitchell. And he says will nuclear be able to scale small enough to power things like large trucks. And George, let me expand that question a little bit because my understanding is that there are these small nuclear reactors. That could be much safer, sort of the solid state ones. That are actually kind of ideal for powering, maybe not a, you know, may, maybe they're the size of a truck. But actually could power a small little city of about 4 or 5,000 pe, people. And in many ways that seems ideal, sort of for third world settings or maybe more remote places. But obviously, then there's issues when you have distributed nuclear material that you sort of run into problem on that. Could you make a couple of comments on both of those? Both the feasibility of it and then sort of the political risk? >> I would say I'm pretty skeptical that say small reactors would ever be used for transportation systems. Whether it's a car, a truck, an airplane. Believe it or not in the late 1950s early 1960s, the U.S. had a pretty serious research effort underway at nuclear powered airplanes. Actually bombers, this was in good old days of the Cold War. Until somebody asked themselves, what would happen when the plane crashes. So I, I'm very skeptical that fission or fusion will ever be used in transportation systems. It just doesn't seem like a good fit. The technology. Steve's question about sort of a related question about what in this country are called small modular reactors. This is an idea where rather than building a gigawatt class power reactor. Which is what we've done historically in Europe and the U.S.. You build the reactor at a scale of meh, maybe 10 megawatts to 50 to 100 megawatts kind of scale. And that kind of power reactor would be relatively compact. It, the idea is it could actually be built in the factory, put on, say a barge or a very large truck without the fuel in it. Shipped sometimes people have actually said, put the fuel in it at the, at the factory, but keep it inert. Ship the entire thing, which might be a few meters in diameter, ship it to the reactor site. You drop it in place and in a relatively relative being like maybe a year or two, as opposed to a decade construction time scale. You'd then be ready to commission the facility. And so there, there is a number of such designs being actively pursued in the, in the U.S. right now, as well as in India and in China. They haven't been commercialized yet. We will see whe, whether they are economic and economically viable. There are many arguments made in their favor. But you know, I've also read criticisms that ultimately they're going to nationally be more expensive on a per unit energy basic than existing technologies. So I'd say they're on to development it's not a lot of, it's not fundamentally new physics involved. It's just new engineering designs that have to be built, tested, and tried out in the marketplace and see whether they work or not. But they are harder elements here as well as elsewhere. >> And George, sort of implied in your response, there is, that these things are sort of by their nature a little safer than the big. You know gigawatt plants? . >> At least the from on paper they should be. The main weakness in light water reactors which is the predominant reactor design around the world today. Is that fuel elements that are used in the can if you lose cooling after you shut down the reactor. If you lose the coolant in such systems, the fuel can get hot enough even in with even after the reactors shut down that it can fail. It can melt or it can over heat to the point where release radioactive products into the air. So these alternative reactor designs by changing the material of fuel elements. By reducing the power density in the reactor itself. And by, by clever design of the heat removal systems. Try to make it so that it's physically impossible. Or the fuel to overheat to the point where the fuel can fail and release fission products into the environment. And so certainly on paper that has been, that's the way they look. And there have been, back in the 60s and early 70s there were prototypes tested of these kinds of designs in the U.S.. That actually lends some credence to the arguments and those engineering analyses. But you know the proof is in the pudding. You've got to actually build them and demonstrate them in a real environment. Not just in a laboratory setting. And convince yourself that, that is really true. I'm convinced, if indeed we can show that that is the case. Then there ought to be a, a significant advantage for those new technologies over what we're using today. But it still has to be demonstrated in real application and that's kind of, you know, but tho, those designs are under study in development now. So we'll see how that plays out over the next five or ten years. >> Okay, and, and I think you already mentioned a little bit about this. But maybe if you can just say a couple more words, and here's the question. I'll read the whole question and then you comment on the parts, okay? I read about thorium. According to what I've read, the reactor is safer because it doesn't need bit containment, waste can't be weaponized, it's abundant, it's proven. And there's plenty of material. Is this true? And why don't we use them now if all this is true? >> A large fraction of it is true. There's lots of thorium around in nature. The it is true that if you built a reactor using thorium. And it was, it's actually been done at least once or twice back to the end of the 60s early 70s. it's, I wouldn't say it's impossible to use the resulting, facile material for weapons. But it is extraordinarily difficult, for the reason that that material, can emit very intense radiation. To the point where the radiation emitted from it essentially destroys the electronics that you require to, to control weapons. And also probably would kill most people who chose to be around the material long before they turned it into a weapon. So it's kind of in a perverse sense the materials still radioactive that it's virtually impossible to use for any kind of weapons application. The reason that it's not in widespread use already is sort of multifaceted. First of all, it would be difficult if not impossible to use today's lightware reactor designs with thorium. The reason is, is that thorium in nature is not fissile. It has to be converted into fissile material. And the way you do that, is you basically take some uranium, you build sort of a conventional fusion reactor. Then you pack some of this thorium in, mix it in with the uranium. And then by by being exposed to the neutrons in that reactor, it'll get converted into usable fuel. But you then have to then sort of separate that thorium material out and build it into its own fuel elements and then put those back into a reactor. So that, we know how to do that. But it hasn't been, again, developed in detail. In the United States, at least. It's my understanding that India has a particularly blessed with very large, thorium reserves. So the Indians are, supposedly trying to engineer such a reactor, and then build it and demonstrate whether it can be used or not. So, I'm not aware of any active development programs in the United States. I might be wrong there. I might be missing something. I know there's, there are many advocates for such an approach in this country. But I'm not aware of an active research and development program to actually build such a device. But, it's my understanding that India is doing that. >> Okay. All right. We're going to, we're going to jump back and take one that's near and dear to your heart. Back to fusion. And it says, what kind of vessels can handle a nuclear fusion reaction? >> Well the, The, the nuclear fuel in a fusion system is not contained or confined by the reactor vessel itself. The fuel would actually be need to be kept away from the walls. Mostly because the fuel, at least in a magnetic fusion energy system, the fuel is so low density. So rarefied. That if it touches the cold walls the fuel cool down and the reactions will stop. So the main challenge then is, is not you know how do we contain the fusion plasma with a reactor vessel, that's done with magnetic fields. The main challenge is if you succeed in making fusion energy. That material's now exposed to extremely high heat fluxes and very intense neutron irradiation. And frankly we need to develop some new materials for that. There are certain classes of steels that have been developed in Europe that look promising. Others propose refractory materials like Tunston, that would perhaps withstand that environment. But the material sciences tell me that ultimately we're going to need develop new alloys that would be combination two or three elements. Probably engineered on the, what's called the nanometer scale. That is you'd, you'd figure out how to control the material composition and morphology. So that you can control the, the composition of the alloy on sort of nanometer scales. It's going to need major ma, material science research to make that, to solve that problem. >> Okay so I want to get to one you know we, we try in Office Hours George, not to put you too much on the spot. But, but in Office Hours, we, we know will engage in everything. And will engage in political discourse as well as you know [LAUGH] sort of scientific fact. So here's one that drifts that way a little bit. And I'll, I'll let you comment on it. Because, again, this is really your area. But it's something that's in, in the press right now. >> Sure. >> I think that, don't. Here's the question. Don't you think the total impact. Of nuclear disasters way bigger in comparison, to the competing energy source. >> no. Actually I think precisely the opposite. And here's the, the, the, the energy source that, primarily competes with nuclear is, coal fired power plants. At least in the, the developed world. Or and perhaps natural gas fired turbines. Both of those energy sources are major sources of carbon emission into the environment. And and at least coal also has very significant emission of, trace impurities that are contained in the coal. Like mercury and so forth. And Steve can probably correct me if I'm wrong but, my understanding of like the mercury that's within, contained within, say the large fish that you catch in the ocean and you eat like Tuna. Most of that mercury actually comes from mercury that's been deposited in the oceans by our coal combustion. There are estimated to be somewhere, in the United States, somewhere around 10,000 premature deaths per year, due to the effects of coal combustion. And the precise number of deaths per year for the history of nuclear fission in the United States, is nearly zero. And so, I think those kind of statistics make me think that fission is, frankly much safer. If you look at Fukushima. This may get me into hot water, but the World Health Organization not a particular nuclear oriented organization, but the WHO, looked at the health impacts of Fukushima. And how many people were expected to the quan develop cancer in their lifetimes as a result of the radiation exposure. And they concluded, based on the epidemiological studies, that the answer is essentially zero and that the major source of health impacts from Hiroshima, is actually the stress, the psychological stress, caused by being relocated from the reactor. And if you actually look at, radiation exposure in the regi levels in the region, I'm not talking about right at the reactor site, but I'm talking like several kilometers away. Those exposure levels are no higher than what people living at high altitudes like in Denver and other cities around the world. What they experience just from cosmic rays. And so the frank reality is that our, our you know, the actual physiological damage that will be that would be received from staying in place. Is actually relatively small and the biggest risk is all the psychological stress caused by moving. So that, that comment's probably going to stir up a storm but, that's what the WHO said. I'm just, kind of reporting what, what I read. And so- >> Wait, let me make a comment here. >> Sure. >> so, so I was just in Japan last fall last November. And we actually had the, the meeting was on bio energy and renewable energy, because obviously the Japanese are very concerned about trying to replace this. And, and here's the most amazing statistic that I heard. That the cancer rate in Nagasaki and Hiroshima, of people who stayed there after the atomic bombs were dropped in World War II, and lived their entire lives in those two cities, had the exact same cancer rate as, anyone else in Japan. So, zero increase in those two places. And that, to me, was a real shock. Because as an American growing up we always imagined, and, and you know, I don't know that, that we ever learned this in school. But the assumption was always that the cancer rate, from those atomic bombs must be enormously high in those places. >> Right. [CROSSTALK]. >> And it actually has turned out not to be true at all. And then and, and then just to tell you about mercury. So it's not the majority. It's all, of the mercury- >> I see. Fish in the Pacific can be directly traced back, to mercury that comes out of the coal plants in in, in Asia, China, in, in India, primarily. >> I mean this whole issue about reactor safety and impacts of large scale nuclear accidents. At the end of the day it's, there's the, the the, there's the reactor design issue, which leads to the possibility or impossibility of such a catastrophe like Fukushima. And so that's what the engineers need to deal with in coming up with better, more clever designs in my opinion. And in the second issue that we've been talking about, the rad safety is is, there's an entire sort of, debate in the literature. Scientific literature about, the health effects of very low dose radiation exposure. And you know, two different very distinguished groups, the French National Academy of Sciences, and the US National Academy of Sciences, have looked at this issue and come to extremely different conclusions about the risks of very lose dose radiation exposure. And you know, the projections of for example if you look at projections of health impacts of Chernobyl on cancer rates in Europe and Russia. And you'll see some groups saying that millions of extra cancer deaths will occur and other groups saying well, it might be a few hundred, over a century out of a population of, you know, half a billion people. Those are wildly different estimates. Well they come at the end of the day from who's modeled for, you know, the health effects of extraordinary low dose radiation exposure. And it's an issue, it's, the sign to [INAUDIBLE] frankly that's not well understood. But if you so anyway. It's, it's an, an area that needs additional work but it, it looks like from things like what Steve was just discussing. That, that extremely low does radiation exposures, may not actually lead to any corresponding increase in in in cancer or other disease. >> Yeah, I think- >> But now I hesitate to add, that is, I am not an epidemiologist. I'm not an expert. >> Yeah [LAUGH]. I think most of our students would be shocked actually. one, on e of the things that shocked me years ago, was when I took a Geiger counter. it, it used to be in molecular biology, we used lots of radioactive substances. P32 is the most common one because we could follow DNA and RNA around the cell. So, every molecular lab in the world always had several different Geiger counters on it, and, and I think the thing that shocked me the most was to go to the potassium chloride bottles. Actually that's salt, sea salt. And you go to the potassium chloride bottle naturally occurring, pulled out of you know, just evaporated salt water there, and hold a Geiger counter up to that and it would go off scale. In fact there are lots of naturally occurring you know radioactive compounds that, that are decaying, in just part of the world. It's, it's what we live in. >> You know I would encourage students if they're really interested in this topic, they could go to Google and search for, the World Health Organization report on the, the anticipated health effects of Fukushima would be, they, they would learn a lot. >> Excellent, thanks. Okay, so along that same line. And, and George, by the way, just so you know. There's a couple of questions here on my list about genetic engineering. I'm going to take some heat, too, a little bit later for what I work on. [LAUGH]. >> And I was just going to pound you all day. >> But, but, but here's another one it says, is there a friendly solution for nuclear waste. And, and let me, let me put a little bit different spin on that. Is there an economic solution for nuclear waste? So tell us a little bit about Yukka Flats and why we don't use it. >> Sure. >> Why we should be >> So I'm going to call it spent fuel, because I think that's actually a better, description of what we're talking about. So spent in today's light water reactors you, stick these fuel elements which are kind of pencil shaped, about 2, 3 meters long a centimeter in diameter and there's thousands of them in a reactor core. You run the reactor for, probably 18 months to two years or so, and then the fuel is considered used up. And so then it's considered to be nuclear waste or spent fuels, I'm not going to describe it. The reality is that yes it has it has a very significant amount of fission byproducts and it mostly gaseous species like xenon and krypton and so forth. As a result of the fission reactions but, about 95% or more, of the original energy content in that fuel, is still there. You haven't burned up all the material, most of it is actually still there. The reason that the fuel has to come out, is because the presence of those fission products, renders the, the fuel elements no longer usable in the reactor for several reasons. One is, those fuel up, those reaction products can sort of poison additional ongoing, nuclear reactions in the reactor. And the second reason is because, the material that surrounds the fuel elements, so called cladding begins to get mechanical stresses in it. Because of the presence of these gases that are trapped in the solid material and so the, the fuel has to be taken out. It has to sit in a, a pool of water for several years until it no longer, has a lot of heat production in it. And than that fuel is considered, now waste, and you gotta do something with it. The mu, there have been multiple, multiple National Academy studies in this country and in Europe, and the generally accepted solution is to find a geologically stable region. Usually a salt mine or other region that is far away from fault lines, earth, you know, earthquake zones, volcanoes, all those sorts of things. And you bury the fuel some several thousand meters below the surface, and you back fill it, and you bury it. And so that's been what most National Academy studies around the world have said is a safe way to dispose the fuel for something like 100,000 or a million years or so. In the US we had such a site under development in Nevada called the Yucca mountain. And for, both technical and political reasons a few years ago actually when the current administration came into office it was it was a, the, the plan was essentially abandoned. I believe that the Finland, of all places, is opening the first, the world's first deep geological spent fuel repository, in a salt mine. That's several thousand feet underground. We have a similar solely in New Mexico called a waste isolation pilot plant with That's a salt line that handles, nuclear waste from our weapons program, but it's forbidden by law, from accepting any spent fuel. So right now, the spent fuel's just accumulating on site, and all the reactor sites around the country. And that's probably safe to do for something like a century or so. but, we need a longer term solution. And so, it, it's ultimately either going to be some sort of deep geological, burial. Or, a technology that allows us to recycle the fuel, is developed and then the energy content of all those spent fuel rods can be actually used by human beings. Which one is more economic, which one's cheaper? Time will tell, I don't know. >> So, so, but I, but I have read a few places, and I think I've heard a few places that there are parts. Don't, don't the French spend some effort recycling their- >> Yes. >> Their sort of spent rods? >> Yeah, they have a on the seaport at Le Havre they have a, huge recycling facility. It's my understanding that it, kind of works but it's quite expensive. And so it, I, I don't, I wouldn't say it's a, a, a complete victory, let's say, or a complete demonstration that that's viable, economically viable. Technology it's, we, we know how to do it. But it's extraordinarily expensive to do in a safe way. So and, and, and right now there's no, you know, uranium based fuel for fission reactors is cheap enough that, it's cheaper for the power companies just to go out and buy fresh fuel rods, rather than to recycle their spent fuel. But they're essentially deferring the problem off, kicking the can down the road, as you say. >> Yeah. But, again, we never do that here in the United States. >> No. >> [LAUGH] Okay, I'm going to, I'm going to take one question just so I show you that I'm willing to take heat too. [LAUGH]. >> And I'm going to let you comment on this one as well George. Because I'm sure you'll have a difference of opinion than me. And the question is, this one's, you know? Every week we had not only, you know, like for example this week we had not only your lecture on nuclear power, but we also had one on, on plants so. The question is, has genetic engineering been proven, beyond reasonable doubt that it is safe? So I, I'm going to answer that and then I'm going to let George [LAUGH] answer that as a nuclear engineer. So look every single organism on the planet whether it's one we eat like, for an animal or whether it's humans or whether it's insects or bacteria, go through genetic rearrangements all the time. In fact there are organisms on the planet that make their living by sampling DNA in the environment and sort of pulling in. And and looking for good genes that might be out in that DNA. In fact there was a beautiful study last year, of a specific bacteria that lured, lives in these thermal hot springs up in Yellowstone, that has an enormous intake of DNA. Because it's sorting through everybody else's DNA out there to see if it finds one that's more advantageous for the environment it wants to live in. So, you know, genetic modification, goes on all of the time, in every organism. That is mutations. That is natural selection. That is how evolution works. So what the real question is, is- There's genetic engineering where we have specific knowledge, where we're going in and pulling out a single gene, because it has a trait we want and putting it into another organism. Is that proven safe beyond a shadow of a doubt? Yes. With one enormous exception. Okay? What's that enormous exception? That enormous exception is that, if you're a scientist, and you want to bring a new flavor into, into a some plant that you're growing. I, I want to make my watermelon tastes even sweeter. I know very well what genes I want to put in there, to bring about that trait and if I'm ethical and, and smart I put in the right ones, I test them we're good to go. There are set of organisms on the planet who spend their entire lives, trying to kill other organisms so they can eat their dead bodies. Okay this is what a bacterial infection is, is doing to you, right? They, they are squirting toxins out, to treat you poorly so they, they can live on you, when you're going down. If you so choose, right? As a scientist, you could pick up some of those toxins, you could pick up some of those nasties, and you could put them into an organism and make what was previously a safe organism now unsafe. All right? So, safe when it's done reasonably and ethically, right, the knowledge to do it, we have to do it correctly, does that mean that any powerful technology can't be taken, and, you know, and used for, I can't remember there used to be an expression on a. You mean can't you use it for good instead of evil. Well you know you, you can you know there are scientists who can make these things for evil. But why bother to go and engineer an organism to do that. Instead what you do is find one that is already a nasty pathogen. And then grow that up and spray it out into the environment. And this is exactly what happened in the United States about 13 years ago. When somebody took an anthrax bacteria. This is a bacteria that's in the environment all the time, but they grew it up they, they, they so called weaponized it. Which means they put it into a very tiny cellular form that easily got airborne, and then they put it in letters and mailed it to people and people got anthrax infections from that. And some of them got sick. Okay so is, is it safe. Safe in the sense that it's not the process of engineering that makes either a good or bad product, right. That's the way it's designed. You can design these things to be bad. But there, there's nothing inherent in genetic engineering that makes it unsafe or bad process. And George, you live in the world even though you're not a molecular geneticist, [COUGH] you can have your say on that too. >> All right, you can, you can abstract out of that response of, you know the key idea that technologies in and of themselves are just sort of amoral since they have no good or bad aspect to them. It's how people choose to use them nuclear technology a good example of that as well. The point I guess that I would also make in response to the students question is, what is the benefit that we get from using these technologies, whether it's nuclear or renewable energy or genetically modified organisms. And in the case of growing food, it's my understanding that. Those techniques could potentially allow humankind to grow significantly more food than we do at present, probably with less impact on the environment. And you know, if we're heading for a world of probably nine to 12 billion people before our population sort of plateaus out at, towards the end of the century. We've gotta figure out how to, how to feed those folks in a way that doesn't wreck havoc with the environment. And I would say, we also have to figure out how to provide them with the energy they need to live reasonably well. Again, without wrecking havoc with the environment. And all of these technologies not just GM organisms and nuclear tech, but all of the technologies. We have to look at them very carefully, and how do we solve the main challenge? Of how do we sustain the human population towards the end of the century? It's going to be ten billion or more of us. >> Yeah, I think one of the things that was really, you know, sad for me. Because I, I grew up before GM Technology was around. I, I saw [INAUDIBLE] process develop. And the, the actually group that organized the sort of disinformation campaign against GM plant technology food technology was actually the chemical industry. And the reason they did this was because, at the time, they were making a huge amount of money selling chemicals, organophosphates, that were used to kill insects on plants. And one of the first GM technologies that came around, was a, was a protein, that came from a, a very specific bacteria, that when fed to feeding larvae, to insect larvae, would stop the bug from eating. It, it's they're called cryogenic proteins, but what, what they do is well when, when the worm elapdopteran larvaes, so when, when a worm eats these things, it actually plugs a little censor on it's stomach. [SOUND] [INAUDIBLE] And, and, and tricks the worm into thinking that it's full so it stops eating. And so when that technology came along it was going to complete displace organophosphates. So, the chemical companies that made organophosphates. Which by the way in the United States at that time were killing about a dozen farm workers a year, because these are, you know? The, the toxins that kill worms kill people pretty well too, you know, the, the, the, the pesticides. So, it was a campaign this sort of, this disinformation about how bad GM crops were going to be and it's really sad, right? Because that was nothing but those company's sort of I would say being greedy and not wanting to lose market share that they came out and started a disinformation campaign, and then for reasons that are completely unclear that stuck with the population and they decided that you know, especially in Europe, less so here in the United States and in Asia. But, but at least in Europe, it sort of stuck with the population that oh, genetic engineering is inherently unsafe, and that is completely untrue. Right? Okay, so we are going to pick another question here. And we're going to go really far afield on this one. George and I are probably not the best person to answer this but we're going to say something about it. So here's the question. What kind of inertia does the Earth's ecosystem have? In other words if we completely stopped carbon emission right this second how long would it take for the Earth to recover and cool down and return to normal CO2 levels. So, so, let, let me start with, with a little bit about that. So if you look over geological time, right? If you look over the last several billion years, at one point, the Earths's atmosphere was 20% CO2. So, humans and no animals could live in it. Then cyanobacteria showed up. And they started eating CO2 and putting out oxygen. And so, over time, the CO2 levels started to decrease, the oxygen levels started to increase. And at some point it made it very pleasant for mammals to, to survive on this planet. So, the actual CO2 levels that we're at right now. The last 400 parts per million. Those are levels that are actually, on geological times, very slow. The biggest issue on carbon flow now, and, and by the way, CO2 levels come and go all the time every winter and every spring. [SOUND] In, in, in the winter there's a spike up in CO2. In, in the summer time it goes down a little bit, the reason for that is because plants are fixing CO2, there's more land mass in the northern hemisphere, so when when, when we have our norther hemisphere, the southern hemisphere winter, we tend to pull more CO2 out of the atmosphere. Also more CO2 is put out into the environment. So, the, the idea is not that CO2 is a normal part of the environment, it's been here forever, it's always going to be here. What is different this time around is that we are rapidly changing the level of CO2. So, over the last 100 years, we have increased the amount of CO2 in the atmosphere by 25%. That is a process that as we look back over geological time, takes 10,000 or 100,000 years. So, it's this really rapid change that's going to get us. We will adapt to higher CO2 levels. If we have enough time, animals, plants that migrate you know, farther north when there, there's more CO2 and it's warmer. Farther south as the ice age come and it goes back down. So, so it's not the absolute amount of CO2 in the atmosphere right now that is so alarming to us, it's how fast it's changing. Because when the CO2 levels change really rapidly, that means the environment, the climate changed really rapidly and we simply lack the time to adapt to those things. >> Yeah. >> So, that's really the biggest problem. There's, there's an enormous carbon buffer on the planet. Both in the oceans. Both into forest everywhere. The planet will eventually take care of this. Who will be impacted by this are the animals, the plant species and the humans simply because we don't have time to adapt. George, do you want to make a comment on that? >> So, you know, I would follow up with, with Steve's answer in that, because of this rapid disturbance that we've occurred. We've been induced in the CO2 concentration of the atmosphere. Certainly the, you know, the distribution of plants water vapor, rain, temperature they're all going to shift. We may or may not like the way [LAUGH], the way that they shift, how do they shift into. It may or may not be convenient for different regions of the world. And that will cause significant stresses for human populations. If you look at the I think the student also asked the question you know, if we, if today we stopped you know spewing CO2 into the atmosphere, how long would it take to sort of relax back to the original state. You know if have a small disturbance away from the earlier equilibrium, then, there are several different rates of exchange of CO2 between the atmosphere and the Earth's surface, the oceans, and the biosphere. But those time scales are sort of measured in centuries. And so you know? If, if you had a small disturbance away from equilibrium, and then you sort of took away the disturbance it would take centuries to relax back. But the other point to emphasize to students is that the, the Earth's climate system is, is a complicated system that has many feedback loops in it. And tho, that's, that leads to what's called non linear behavior. And in in that kind of a system, if you disturb the system far enough away from its earlier stable state, it might never relax back to the, the old state. It might choose to fall into a, some, something quite different. And that kind of non-linear response is quite difficult to predict. And could, and frankly, we don't know where those tipping points or those, those thresholds really are. It's hard to predict those with precision. But we know that these kind of complicated systems do have those kind of bifurcation points. And so yeah if it's a small disturbance, it's a relaxation time scale measured in centuries. Maybe even a millenia or so if it's a really large disturbance. Like, let's say we double or triple carbon concentrations over the next 50 years, which is entirely possible we don't quite know how the system will respond to that big disturbance. It might relax back, if we stopped fossil fuel combustion? It might go to a different state. And we don't know what those states are and we don't know where the boundaries are. >> Yeah, so we're just about outta time here. So, so I'm going to end this. We're supposed to comment on it. Question then I'll let George have a last say in this too. >> Okay. >> So, one, one of things that really concerns me about climate change is that the people who are putting most of that carbon into the atmosphere are those of us in the first world that, that, that have large economic resources, we're the people that own the cars, we're the people that own the factories. And frankly we have enough riches, we have enough money, that when you know, things change we can adapt to them. Right? We can move to a different place if there's too much rain. Or we can change our agricultural practices, if we, if we go into drought. There, there's lots of ways we have to sort of mitigate the suffering that will be put on us. The people who don't have that opportunity are the countries that don't have money, the developing world. And it, it's the really sad part for me is that the people who will suffer the most, because of climate change. Are the people who are doing the very least to cause it. You know, it, it's the countries like Nepal, You'll, you'll hear a lecture from, from Alex Zahn at the, at the end of this series about electricity use in Nepal, which is five watts per person, per day, okay? Not kilowatts. You know, five watts. And so, so they're using a fraction of the energy we do. And yet even today they are suffering from climate change, because of the melting of the glaciers in Nepal. Because of the altered runoff of the water, et cetera. So, a very small change in climate for them can have an enormous impact on them, much bigger than it does to us. Okay? So, we, we're out of time for today, George. I'm going to give you one last chance to make a comment, and then we will sign off. >> I would just follow up comment. It's also a generational aspect to this. That in, in addition to the geographic and economic aspects of who, who will pay the price. It's also in addition to the poor regions of the world today will pay the price for essentially the sins of the, of the rich world. also, if you look at where the biggest impacts, or when the biggest impacts occur. It will be long after Steve and I have, have moved on and, you know? It'll be our children and our grandchildren, and great grandchildren who really bear the brunt of this. And so, there's also an intergenerational issue it really is a very deep. I think moral issue as well as a scientific and a public policy issue. >> Yeah. Very well said. And, and all I'll say on that George is I have my new electric car. And I'm putting up floatable tags next month. What are you doing for the planet? >> I, have my house uses zero net energy. It it we had Schott PV panels and they actually work quite beautifully. So, I actually have no net electricity bill at the end of each month. >> Hey, you're ahead of me again. >> [LAUGH] [CROSSTALK] You're not trying to make fusion work, so. >> There you go. George, thanks very much. Thanks to all the students for signing on today. And we will see you guys next week. George, have a good weekend. >> You too. Thanks Steve.
