EnergyTransition-04 Nuclear Energy: The Solution?

Hello everybody! I would like to welcome you to my next lecture today and we will ask the question if nuclear energy is the solution to the world energy problem. if you look at my first diagram here you see the energy consumption, as I showed you already in my last lecture. this time it is plotted from 1965 to 2015, so exactly 50 years, so what happened in the last 50 years about energy? well you see these lines here. The upper curve is oil, then you have coal and then your have the gas. you see that especially the gas had a linear trend in the last 50 and even longer years and there’s been a lot increase of fossil fuels, as I told the last time. we have 80 percent fossil fuels in our world. the unity is Tera-Watt-hours per year.

if you want to convert it to gigawatt as I did 01:03 - last lecture, you have to know how many hours there are in one year, and you have to convert it. if you sum up the curves to come to about these 18,000 gigawatt which, I gave you last time. now today we talk about the red line. the red line gives you the nuclear energy and the question is: nuclear power has been there since the 50s so we have now 60 years of nuclear power. why did not happen more to it, why is the fraction of nuclear power still so small? therefore let’s have a look in detail what this red line looks like. so on this plot here you see that the red line which is the amount of nuclear power is on the plot as well.

this is what is called the realized 01:56 - capacity and the blue curve is the installed capacity, so that tells you how much nuclear power there could be if all nuclear power plants would be operating. so what you see on this plot here is that there has been a large increase of nuclear power starting in about the 70s and it had some quite steep rise but then in about a year 1990 it stagnated. what was the reason for that? well you all know there was a nuclear accident in Chernobyl and a big part of Europe and also the rest of the world was contaminated by some radioactive clouds which were passing around the globe and people realized that there is an inherent unsafety in nuclear power which a lot of people told us before but it was not the common belief at that time. so after Chernobyl a lot of the nuclear power was reduced, meaning that newly planned nuclear powers were delayed and some of the old reactors had to be switched off and since then the increase of nuclear power is almost zero, so we are at around 400 nuclear power reactors which are operational, sometimes more sometimes less, and then in the 2010s there was the accident in Fukushima which again caused a problem to the nuclear industry and even more people were now convinced that even in a highly developed and industrialized country which has a lot of safety regulations, nuclear power is not really safe under all circumstances. so to summarize: in the last 65 years nuclear power has been installed, there has been an intense support by the government.

if you think about all this billions of euros and dollars, 04:15 - which went into the research facilities to better understand nuclear power, and still today after these 65 years, we have less than 300 gigawatt installed nuclear power, our operating nuclear power, compared to the 18,000 gigawatts, which we have as a total primary energy use on this world. this is only 1.6%, so it’s negligible. of course if you add the waste heat for example then you come up to something like five percent, but still compared to the primary energy demand of our world is really a small number. how can we understand that? well let’s first have a look at the advantages of nuclear power, because there’s a huge community of fans of nuclear power, which say this is the future solution. well the big advantage of nuclear power certainly is the high density. you have a small area where you built your nuclear power plant and you can produce a gigawatt, or you can build, like here in this picture, even 4 of these nuclear power plants in one area and you have a multiple of this high energy output.

it’s stable usually and it is available day and 05:43 - night so there’s a big advantage of nuclear power in this sense. the second big advantage of nuclear power of course is, that there is basically no co2 output during the operation and in view of the climate change this is of course a big plus. of course, you have to take into account that for producing these power stations and for producing the fuel and for saving the fuel afterwards, you need co2 output with the current technology, but this is a minor point in our context. the other thing is that it’s relatively small costs to make such a nuclear power plant and to operate it. however this is also not true anymore nowadays.

we found out that you have to 06:38 - have a lot of safety standards and if you apply all of them and if you talk about external costs you come to the effect, that nuclear power is not really cheap, but I can’t do this later again. and of course the other thing is, there is little waste so you have a few kilograms probably per day. the amount of radioactive waste is small but of course it’s dangerous. so let’s come to the disadvantages of nuclear power. the disadvantage of nuclear power is that you of course have only a small area where you operate a nuclear power plant, but you need large- scale uranium mining.

uranium is quite rare on our earth and if you want to get it you normally have 07:30 - to have big mining areas because fraction of uranium in normal stones in this areas is very small. so you basically have to dig around whole mountains to get enough uranium. so in this picture you see a uranium mining in Namibia in the south of Africa. This area you have to add, if you talk about the effect of nuclear power on the landscape. the second point, is you have to process what you are mining, so you need chemical, radio-chemical industry which treats your material to get the uranium out of this material and later when you have produced electrical energy from your uranium, you are left over with waste and then you can either store the waste or you re-process the waste again and this re-processing requires again radio-chemical factories which treat radioactive waste at large scale and which have a lot of potential problems, they are dangerous to the environment.

if you 08:45 - don’t treat it, you have to dispose the radioactive waste and the radioactive waste is still radioactive for a long time. we talk here about thousands of years, so a lot of generations, and thirdly the cost for safety are quite high, as I explained before. if you have a closer look to radioactive waste, well of course, you don’t put the radioactive waste somewhere in the landscape but for example in Germany we put it underground in old mines, very deep under earth. then in Asse for example, a few decades later, we found out that this area there is not safe. water is going into this salt mine, so in the next decades all the radioactive waste has to be taken out again, which is very costly and then we have to store it somewhere else, where it might be more safe.

so let’s 09:45 - have a closer look to the radioactive waste of a nuclear reactor. here the vertical scale here tells you in an arbitrary unit how much radioactivity there is still in the nuclear waste. it’s a logarithmic scale and on the x-axis you have the number of years since radioactive waste is taken out of the reactor, al so in the logarithmic scale, and you see with some wiggles, the thing goes down, but you see the scale is, that it takes hundreds of years before radioactivity is really at a very low level. let’s talk a little bit more about the costs of nuclear power. well, I said nuclear power in principle is cheap.

if you do it for the first time 10:38 - and you have some uranium available it’s not difficult to produce a nuclear power station. but to produce it in a safe way, this is very costly and it turns out that today nuclear power is economically not competitive anymore. one example, one negative example of course is the new European pressure reactor. this is a reactor which is built by Europe, so a big part of it was France and Germany but because of German policy at the end it’s basically a French reactor. the original cost estimate was that this reactor will deliver nuclear electrical power for a price of about 3 euro cents per kilowatt hour.

so this is rather cheap 11:36 - nowadays and that was the original estimate many years ago. since the reactor was designed and now it’s being built, the prices went up, a lot of the things go up because of safety requirements, the funding of this nuclear reactor in England was a big problem at some point, so at some point the British government gave the contract to China and EDF, which is mainly a French company and the British government gave them a guarantee of a price of 10.7 cent per kilowatt hours and this is guaranteed to these Chinese and French companies for 35 years. so for the British people which want to use the nuclear energy as electrical power at home, this is a rather expensive business and in addition to this 10.7 cent per kilowatt hour, which is already very high, you have of course the external costs which have to do with the damage and safety and environmental effects, which nuclear power and nuclear waste have in the long term.

so in this respect I think in principle we could 13:08 - stop the discussion here. nuclear power is economically not competitive, so we don’t have to talk about it. but of course the community of nuclear energy fans is so big, that we still have to find some more arguments about nuclear energy convince everybody. so I myself I’m a particle physicist and particle physics is very much related to nuclear physics and of course I’m teaching also nuclear physics and particle physics in university. so I always wanted to understand nuclear power in a bit more detail and when I was younger, I was also not really convinced what’s the best solution for the future is.

and 13:57 - of course as a nuclear physicist you try to invent something, which makes nuclear power safe and cheap. yeah. I have been studying in Aachen, which is close to the Belgian and French border of Germany and close by there is or there was at this time a very modern research reactor. it was called in German the Kugelhaufen reactor because nuclear fuel was looking like small bowls, as you know them from billiard about this size, made out of Thorium and out of graphite and this Kugelhaufen reactor was - as it was later discussed - basically inherently safe. so the idea was that if you switch off the electricity, if you don’t operate your nuclear reactor anymore, it should not explode, it should go to a stable situation and this you can do with this is modern type of reactors. today you call this type of reactors very high-temperature gas-cooled reactors, so this was cooled by helium, which cannot burn.

it was using 15:22 - very high temperature which means that you have a very high efficiency from converting nuclear power into electricity and it also means that they can cool itself basically. so if there’s a problem with the operation normally they don’t heat up too much. and they also were quite small, so that the total amount of energy was limited. this kind of reactor was later studied in South Africa and then in China and in the US as well, and they improved it but for some reason this is still not state-of-the-art. another thing which I found very interesting during my studies was what was called the energy amplifier.

it was invented by a Nobel Prize winner in particle physics: 16:20 - Carlo Rubbia. some people therefore called it the Rubbiatron. Today you call this kind of “energy amplifier” the accelerator- driven subcritical reactors. those machines consist of a nuclear reactor which is subcritical, which means which normally do not produce nuclear energy Because to run a reactor, you have to make it critical so that the nuclear reaction stays constantly on. so how to produce with a subcritical reactor nuclear energy? Well you can do that if you add neutrons and these neutrons were produced in accelerators.

these accelerators are known from the field I 17:11 - work in: particle physics where we have particle accelerators and with them we can produce neutrons and make nuclear energy with a subcritical reactor. the big advantage of such an energy amplifier is that - as soon as you switch off your accelerator - the nuclear reactor becomes subcritical again, so it’s switched off basically. and in this sense it sounded like a very safe and very great idea from Rubbia. the other nice thing about it is that you can use it for transmutation. so if you have some long living radioactive material like plutonium which you have from bomb production, from nuclear bomb production you can put it into this energy amplifier and then you produce energy from the plutonium and at the same time you convert this plutonium into something which is less dangerous. you can also do that with nuclear waste.

so this is a way you reduce the amount of 18:15 - nuclear waste and to make the radioactivity which normally lives for ten thousand years, you can reduce that so that as well the amount of radioactivity as also the lifetime of it becomes smaller. so this energy amplifier looked as a really good idea to get rid of the risks of nuclear energy, but if you think about it more deeply you’ll find out that the risk is inherently in the reaction there, and even with an energy amplifier and a subcritical reactor you don’t gain very much in risk. in addition your add new risks, which you didn’t think about before. the same is true for these transmutation machines also there you have a certain class of risk. so what are these risks where I believe that they finally are the no-go criteria for nuclear fission? well I say two of them and this to my mind is valid for all nuclear fission reactors.

the first point is that a nuclear reactor produces 19:25 - heat. every nuclear reactor is there to produce heat and from the heat you produce electricity. the heat has to be quite large because you need a lot of electricity, so typically you have something like for example 3 gigawatt of thermal energy which such a nuclear reactor produces. if you now have an emergency situation, the first thing you have to do is you have to switch off the reactor, which means you have to switch off the nuclear reaction. if this is not done at the very beginning when the emergency occurs, the reactor can blow up as a nuclear reaction and that is what happened in Chernobyl for example, where they took a few seconds to switch off the nuclear reaction.

but let’s say the 20:21 - operation is in a safe mode and they switch off the reaction immediately. what happens then? well you have a lot of unstable nuclear elements in your reactor. they continue to do radioactive decay and with each radioactive decay a reactor produces still heat. that is what is called the decay heat of a nuclear reactor and this happens even after you switch it off. this amount of heat is about 5 to 10% of the original heat, which looks not too much but if you have 3 gigawatt and you take 10% of it, it’s 300 megawatt.

21:02 - so you produce heat at a very high level and if you heat something you have to cool it and then nothing happens. but if there’s an accident what can always happen is, that the cooling does not work. so if the cooling is not working properly and you have a heating of 300 Megawatt, immediately all the material in the reactor overheats which means that the water starts to boil, a lot of the metals will produce hydrogen with the water, and the hydrogen will come out and explode, and that is what for example also happened in Chernobyl and later also in Fukushima. so if cooling is not working properly a reactor that always explode. it will explode by chemical reactions or if the nuclear reactions still works it will also have a component of a nuclear explosion so you always have to make sure if you run a nuclear reactors that the cooling will work properly, in any case, whatever happens.

there are new ideas 22:16 - now in the new versions of the nuclear reactors, the material when it overheats flows down into the basement and distributes there, so that the heat is reduced, but whatever you do you can always think about a circumstance that things happen differently than you believe. the best example for that is Fukushima. you all know there was a flood. The flood flooded the electricity generators, so the electricity failed in this nuclear reactor. without electricity you cannot run your cooling pumps. then the cooling was off and soon later there was hydrogen produced and the hydrogen exploded and as I said before something similar happened in Chernobyl. I don’t have the time now to go into all these details. but my main point is still coming.

it does not matter how well your 23:22 - reactor is built, how safe it is working. if you have a terrorists or if you have a war ongoing in some future, it is always easy to bring any nuclear reactor to explosion by just using the remaining heat which such a reactor produces. there are a lot of scenarios. for example typical scenario which is discussed in the public is that a terrorist hitchhikes a plane and the plane is crashed on the nuclear reactor and then it’s shown that the nuclear reactor has no problems is that. well this is not really convincing, because of course a plane is made out of aluminium and aluminium, if you crash aluminium on a concrete wall, it crashes and it doesn’t make any harm to it normally. The real risk is if you use any weapon and there are lots of weapons on the black market nowadays which are able to shoot holes into a nuclear confinement and therefore you always have the remaining risks that the terrorists buys one of these weapons from the black market and shoots down a running reactor.

in this case you cannot guarantee any more - if there is an explosion in 24:53 - the reactor - that the remaining heat is getting rid off in a controlled way and then of course the remaining heat - the decay heat which would have - this 300 MW for example - they blow up the rest of the nuclear reactor, which was not destroyed by the warhead for example. and when you talk about nuclear energy you don’t have only to talk about next ten years you have to discuss how the future will look like, and nobody of us will know how the future and fifty years looks like. maybe we will have new war zones somewhere in areas where we thought we have a very stable environment. let’s take for example Europe. the biggest nuclear power plants in Europe, where are they? well you might think in France; but that’s not the case. the biggest ones are in the Ukraine and a few years ago there was a war going on in the Ukraine close to this nuclear power plants and any rocket which would have hit this nuclear power plant would have produced a disaster for whole Europe.

26:13 - So this is my first point, but there’s a second point of a high risk for any nuclear reactor. what is the point here? well, any nuclear reactor produces a high neutron flux. so there are lots of neutrons in the reactor which are needed to run the nuclear reactions. the point is, that any nuclear reactor which has these neutron fluxes can be used to produce material which you use for nuclear weapons. for example plutonium. so even if a nuclear reactor is not made for producing nuclear weapon material, it’s rather easy for an operator of such a nuclear power plant to convert it into nuclear weapon factory.

so whenever there is no observation this can be done. this is called proliferation. so you use the material which is used for civil nuclear research or nuclear energy production, you use it to produce weapons, nuclear weapons. and you have to remember if we want to have a significant amount of the global energy demand by nuclear energy, than we need not 3 or 4 nuclear power plants, but we need some 10,000 of them. and it will not be possible to really control and verify that all these 10,000 reactors are operated in a way which is acceptable for the global public. so this is my second no-go criteria for nuclear reactors at large scale.

so if you think 28:10 - about these two arguments I had against nuclear energy, of course you will always ask why do government still build nuclear reactors? Well, of course first of all there’s a big industry behind which has some lobby in the government, but I believe the real reason is another one. if a government wants to build nuclear bombs or is already building nuclear bombs, like US, Russia, France or England and many other countries, of course they need a nuclear industry. so they need experts on nuclear physics, they need experts on the treatment of nuclear waste, of nuclear materials. They need to breed plutonium and other radioactive stuff to build these bombs, so you need an whole industry to be at all able to build a nuclear bomb and therefore of course you also need a civil application, otherwise it would be too expensive. I believe that this is one of the reasons and of course a lot of countries who officially don’t build nuclear bombs but still want to do it, at least in future.

so the point that there’s no safe nuclear power available today does not 29:38 - mean that in the long future, those things will not happen. so there has been a lot of development in nuclear power in the last 50, 60 years but still myself I don’t believe that there’s anything in future, which will not have these two no-go’s, which I told you before. if you look at the diagram, the final generation is said to be highly economical, it has enhanced safety and minimal waste and will be proliferation resistant. what can I say about those future ideas, where nobody knows if it will work? well first of all: if it says it’s highly economical: this is only the case if you don’t add the external costs of nuclear power because we have seen that the nuclear waste has to be safeguarded for many generations. so from this point of view at least nuclear power has to be also economically concerning the external costs.

in addition I believe that renewable energies are so cheap nowadays 31:02 - that they will always be cheaper than nuclear energy. so second point the enhanced safety: they do it either by having large units. then you have the decay heat problem which I believe you cannot really handle it at least not with respect to terrorism. or you use a lot of smaller units, then the decay heat is less a problem, but then you have the problem of proliferation, which means then you can always use one of these many small units to produce for example plutonium or other hazardous radioactive material. minimal waste is produced by using nuclear breeders.

I don’t go to details here, but it is something similar 31:59 - as transmutation. minimal waste what does it mean? well you can run a nuclear reactor by so-called breading you have breeding- reactors in a way that they can use the same material over the over again. you can also do transmutation and gain some energy but all these nuclear reactors which can do this transmutation and this breeding have an enhanced possibility for bomb production so in this respect to me this is not a safe option. and finally the proliferation resistance - already the name says that proliferation cannot be prohibited - they call it proliferation resistance, so the prohibition is impossible and if you have ten thousands of nuclear reactors it’s not enough to reduce possibilities - you have to prohibit it somehow. so whatever you do: to what I believe: I see no way of having a nuclear fission reactor working in a safe and stable way over decades and centuries.

so the other option which is available in nuclear energy is nuclear 33:19 - fusion. you have to distinguish between nuclear fission that is how the normal nuclear reactors work and then in addition you have nuclear fusion. what is the difference? well it’s a difference in the following way: in fission you have a big nucleus like uranium, and you cut it into two pieces and by that you produce energy. in fusion to do the opposite: you have two smaller nuclei. you put them together and they make a helium nucleus or something similar, and this nucleus is bigger and more stable.

so you produce energy when 34:02 - you produce a bigger one from smaller ones. at the first glance that sounds a bit contradictory: what you could then do is you take a big nucleus, you cut it into half, then you have smaller ones and you put it again together and you gain energy in both cases. this is not the case. the solution of that is something that you learn if you do nuclear physics. anyway, you should just remember there are these two possibilities: the fission one is the simpler option that is done in the standard nuclear power plants, it was also done in the first nuclear bombs, like the one in Hiroshima. the fusion is a bit more difficult to handle.

for nuclear bombs it is working since a long time, those bombs are called 34:56 - hydrogen bombs because hydrogen does the fusion and that’s where the energy comes from, and for the application as a power plant to produce power, the nuclear fusion is still not working. it’s a research project since many many years. so let’s have a look in detail about the nuclear fusion, because that could of course be a solution for the future. in nuclear fusion there again two types: one is the magnetic fusion one is the inertial fusion. so for the magnetic fusion the research is working on that since about 70 years. It is heavily funded research, because all the physicists believe, or a lot of them believe: this is the future of our energy system.

one of the last projects in nuclear fusion research is 35:57 - the so-called ITER. it’s a global project and the planning started in 1985. the plan was to produce 1.5 gigawatt of electrical power with it. this is a long time ago. there were delays and problems, problems with money and typical things which happen in these big projects. now the plan is to have the operation in the year 2025 or maybe 35 and it will have not one in the half gigawatt but only half a gigawatt and it will cost more than 20 billion euro. and it’s still rising in costs. if you ask me as a nuclear physicist I am convinced that the machine will work. yeah.

everything has been simulated 36:54 - everybody knows that this kind of reaction will take place, if the temperature is high enough in these reactions and therefore no real scientist has a doubt that the machine will work at some point. the only problems there are technical problems because on the one hand they used superconducting magnets which are at temperatures of minus 270 °C about and on the other hand you need to have very high temperatures in the plasma that you produce and to have that close by is very difficult. the other point is: these machines have to be very, very big. there’s an inherent physical reason why this kind of magnetic nuclear fusion needs these huge machines, which are very expensive. so this will work one day, but to my mind it will not be a solution to the world energy problem, as I come back to in a second.

the other option is inertial, so called 38:04 - inertial fusion. there you heat up a small droplet of material - like deuterium or something else - and by the heating then you produce such a high temperature that the nuclear fusion happens by itself. and then you can imagine it as a small hydrogen bomb - a small nuclear explosion - but because you do it only on a small droplet the explosion is limited and will produce a little bit of energy and this energy is collected and then you explode the next droplet. Droplet by droplet you produce nuclear fusion energy. this research is quite promising nowadays, but I have a big problem with that, because if this works really, at some point it will have a very big impact, mainly on new weapon production and also on military operations.

why is 39:14 - that? because if you can do it with small droplets, you can do it sooner later also with bigger droplets. so the amount of energy which you can then produce is basically scalable, so in a way unlimited and this will change of course the options which we have for nuclear weapons. if you look at the research projects of this nuclear fusion machines, they always are dominated by military applications and in the case of inertial fusion, this is especially the case. so will that solve our world energy problem? well first of all the nuclear fusion at least the magnetic one, will come much too late. it will take more than 30 years at least before there’s a commercial application to it.

and then 40:12 - you have at the beginning just one of these big machines and there are thousands of scientists working for that. From a step of having one with thousands of scientists to a step where you have thousands of these nuclear reactors with a limited amount of manpower, to me as this looks not feasible: first of all they don’t have enough highly skilled engineers to do that, secondly the amount of special materials you need for this nuclear fusion energy is so big, that you will not have the resources for that. so all in all I would say: nuclear fusion energy is not the way to go. the magnetic nuclear fusion will not work at the big scale. it will work on single apparatus but not at a world energy scale that has to work in every corner of the world.

and the inertial fusion has a lot of very 41:23 - dangerous applications, if it would work one day. so I think we would all be better off, if don’t even try to make it working. So I come now to the end of my lecture and at the very end of my lecture I will tell you: nuclear energy is the solution of our world energy problem. but in a somewhat different way as I talked about it before. because you all know the Sun is a nuclear fusion reactor.

what happens on the Sun is the same what happens in 41:58 - the fusion reactors which we have tried to build on Earth. you have hydrogen and this is fused into an helium and by this nuclear fusion the Sun produces its energy. so all the energy which comes from the Sun is energy from nuclear fusion, so the Sun is our “nuclear fusion reactor” and we have it and we can just use it! the Sun of course is highly radioactive. if you come close to it you will have all the radioactive radiation and you will die immediately not only because of the heat but also because of the radioactivity. but fortunately our earth is at a safety distance to the Sun of 150 million kilometers and this is far enough that all the radioactive radiation does not harm us.

the only remaining one which arrives 42:57 - down on the earth on the ground is the ultraviolett light which can produce skin cancer. so how can we now use the energy which the Sun produces on our earth? well in German you have this nice long words. you could call it, what you need is a “Fusionsenergieempfangsantenne”, so kind of fusion energy receiving antenna, in English you call it a “solar panel” and this solar panel can convert the energy from the Sun, which comes in the form of light and heat to our earth. they can convert it into electrical power. how much power does the Sun produce? well it’s 3.8 times 10 to the 26 watts which the Sun produces.

this is about 300 thousand trillion nuclear power stations - as 43:56 - they are produced on the earth. because of the large distance of our earth there arrive 1.4 kilowatt in every square meter. so if you have a solar power plant which is not only a square meter but for example a square km, like a big power station in the desert, then you have the amount of 1.5 Gigawatt maximally. so about the energy of one nuclear power plant arrives on every square kilometer in the desert on our earth. the other good news is: it’s not only enough energy which we can have from the Sun, it’s much more than enough, and it’s a cheap way to produce energy.

the 44:42 - best power stations on our globe today using solar power produce electricity to a cost of 1.5 cent per kilowatt hour which is really cheap. it’s cheaper than a coal power plant or, of course, also a nuclear power plant. so in this respect we have a great future in renewable energies from solar energy. this is enough for today about nuclear energy. next time we talk about fossil fuels again and at some point we will also come to concepts of renewable energy. thank you and I hope to see you again. Good bye. .