Transcript: Could nuclear energy power the world?

Dr Robert Hayes

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Hello. My name is Robert Hayes, I'm an associate professor here at North Carolina State University in the nuclear engineering department and this is my Garden talk. It's been a controversial week and I'm not talking about politics. Um there has been a landmark vote which has seen the european parliament endorsed labeling some gas and nuclear energy projects as green, which allows them to access hundreds of billions of dollars, billions of euros in cheap loans and even state sub disease critics have fought back saying this runs counter to european efforts to slash carbon emissions by 55% by 2030 but it could also increase the risk of nuclear accidents.

Now there's a lot to unpick here. So joining me for today's fireside chat is dr robert Hayes, who is an associate professor of nuclear engineering at North Carolina State University where he teaches health physics, nuclear waste management and radiological emergency response robert is here to provide some background on common misconceptions about nuclear power and to answer your questions and I'm sure you have many, many questions. So do submit them while we're going through today's conversation, just how safe is nuclear power, our nuclear reactors, the answer to low cost electricity access for communities that are off the grid.

And what happens to nuclear waste? Could the negative be outweighed by the positives and could nuclear be the answer to power in the world? We're gonna be tackling all those questions, robert, Welcome to The Garden. Thank you for joining us this evening. Good to be here. Thanks for having me now. Let's start off with the basics. I know it's probably too complicated to go into huge detail, but can you explain how nuclear power is actually generated and why is it so effective? Sure. So it's very similar in many ways to fossil fuels or geothermal or any of the sources where you just simply need enough heat to boil water.

The idea is that when you boil water, the phase transition from water to gas creates an enormous expansion. It's over 1000 times volume when you when you convert the phase and when that water converts to steam that occurs in a turban. And as it comes through the turban, it expands and causes the turbine blades to spin when they spin they turn a dynamo, the dynamo makes electricity and that's really it. Nuclear energy is a source of heat to boil water. That's pretty much it, Thank you for explaining that because I have to say I was trying to remember back to my high school physics and I'm afraid nuclear energy wasn't on the cards back then.

But let's go into some of the questions that we've got for you today. Now, nuclear energy has a bit of a bad reputation. Do you think that's actually justified? And how has that really changed over time? So I I see that it does have a bad rap and I will confess it has a rather sad birth defect that when it was being discovered along with it came nuclear weapons, but it definitely is far worse than it than it should be in the sense that in many studies, we're finding that there are more deaths from fear of radiation than actually from the actual radiation itself.

The fear of it is causing more problems than the actual accidents or harm that that has been seen to come from nuclear energy. So it's it's extremely out of whack in that sense. Are these fears actually justified? I mean, we talk about the fears, I know there's this fear of radiation poisoning or nuclear reactors blowing up. Are those fears justified? What are the risks? So I would say absolutely not. And let me give you an example when it came to Fukushima. If you looked at the radio activity that was released, right, three full nuclear core meltdowns, three through three nuclear reactors, full meltdown.

The radio activity that was released was assessed by the United Nations. They put together an international panel of experts, the World Health Organization. They did the same. There have been many review papers by experts in the field that have published on this and they all had the same conclusion that all of that radio activity was insufficient to create any measurable medical effects in the japanese public. That probably should be reiterated that the dose that the people received was too close to natural background radiation that you get from everyday life from, from radon and from the soil and from cosmic rays that the dose that they got was too close to that to cause anything measurable.

And so even though tens of thousands of people died from the tsunami, people think about Fukushima, but the radio activity was too small to cause any real damage. And yet the only deaths that occurred from Fukushima, which are attributable in a scientific way were from a panicked evacuation. The people were so terrified of the radio activity that they risked and lost their lives to avoid something that wasn't even measurable. So, in a very overt sense, it, I would say it's not justified. It is extremely overhyped.

It's even got its own word, it's called radio phobia. Radio phobia. Well, that's a new one for me. Can we talk a little bit about this radio like radiation exposure? Like how much radiation would you need to be exposed to to actually get sick? Because I know this is one of the main concerns that people have, particularly if they're thinking that they might have a nuclear power plant in their vicinity. So a typical radiation dose that you would get in a year just from natural background, Uh, is uh, something around the range of about say, three military birds in order to get acute radiation syndrome.

You've got to get a full Sievert. So it's, it's over 100 times, uh, just enormously bigger. You've got to get a very large dose compared to the natural dose that you get every year just from natural background from the food you eat, the air you breathe and the environment that we live in. Uh the only kinds of people that get that dose, for example, were atomic bomb survivors. They got a massive dose. Or if you were to say go up and hug a spent fuel bundle, you'll get those kind of doses as well.

So it's really difficult to get those kinds of large doses where you can get acute radiation syndrome And even at those large doses, a full Sievert That will, if you got that over a year, that would only increase your natural cancer probability by about 5%. So the typical cancer probability from all cancers combined averaged over genders and so forth is around 40%. If you got a Sievert of radiation, then then you personally would have an increased 5% probability. So to put that in perspective, if you had 100,000 people 40,000 people on average will get a measurable cancer.

If all 100,000 people got a full Sievert or 1000 millisieverts, then you would have on average 45,000 people get cancer. And you're not going to know which of those 5000 were from the radiation because it's the same cancer. And so you really got to get a big dose for those kinds of things to happen. And the doses that are legal tend to be about 100 times below that many regulations actually will not allow a dose at even a fraction of natural background. That's usually what the regulations are. You can't expose to somebody To a dose.

That's even some, some in some cases on the order of 10% of natural background is what regulatory limits are and people will associate that with safety. And it is kind of an issue in terms of control, right? We have to demonstrate that we're in control of it. And if you're busting the regulation, that implies that you weren't in control. But the regulation tends to be at a fraction of natural background, but you're just gonna get anyway, a small fraction of what you get on average from medical exposures on average.

Again, that's very, very helpful. Just going back to sort of nuclear disasters that have happened. Obviously, Chernobyl has been in the news a lot over the last few months with the war in Ukraine and and this is one of the most remembered nuclear disasters of our time. Can you talk a bit about the radiation exposure that people had their and how that has evolved over time? Because I know that there's concerns about sort of for example, attacks on nuclear power stations. So Chernobyl was just a nightmare case.

It was a bad design, bad operation, bad emergency response. It was kind of like, it would be difficult to intentionally do something worse than that without a nuclear weapon. Um uh When Chernobyl occurred, initial estimates for the cancer rates were in the tens of thousands, it turns out that after the fact, looking back, it's been in the range of a few 1000. Uh and that's largely from leukemias and the thyroid cancers. The leukemias and the thyroid cancers could have largely been avoided if they, if they would have had a proper emergency response if they had told people and they implemented proper protection.

Um, something that's rather unique that's just coming about recently. The latest research is showing that even in Chernobyl, this is almost shocking. It should be shocking to find out that fear was the big killer in Fukushima. But latest research is actually showing that that's probably the case in Chernobyl because when they went and looked at cohorts of the liquidators, the people that cleaned up that actually went in there during the event and after the event to clean it up, uh and they would see that there was no statistically significant increase in their cancer rates.

What they were able to see was shocking and that they had a large statistically significant increase in suicide rates. And they again, attribute this to radio phobia. The people when they've been exposed to Chernobyl, they're stigmatized and they'll attribute anything that goes wrong in their life to the exposure, right? So if you end up having a bad knee or you end up having gout or you have hypertension or high blood pressure or anything, it's easy to say, well, that's because of the radiation so that whenever something bad happens, it reinforces this belief that your doomed, you have no hope that Chernobyl is just condemned you to a life of misery and horror.

And so the suicide rates have gone up. So even in that scenario, it looks like fear is even more deadly than was the radiation. And that's just staggering to think that for even for Chernobyl, that that could be possible. That is staggering. And also gives a completely different perspective on, on what happened there. I want to move on to one of the other risks of nuclear power that people point to, which is really around how nuclear waste is disposed of. Can you just explain how you, how you actually get rid of nuclear waste right now? How long does it take to decompose or decay and what what the future holds in that regard? That's a really great question.

Really important question. So when whenever you control nature, whatever you're going to do, whether it's solar power or cell phones or building houses, you're gonna generate waste products and the different types of waste products have different waste disposal requirements that are going to be unique to that material. So the toxic waste is dealt differently than with sanitary waste than with Uh nuclear waste and they all have properties that need to be mitigated to protect the environment and the workers and the public and so forth when it comes to nuclear waste.

What the latest science is that you use a geological repository. Now, this isn't really that new. We knew this back in the 50's and one of the best analogies that we use to define what makes for good science when it comes to a geological repository is what Nature herself already taught us. There is a natural nuclear fission reactor that occurred here on earth about two billion years ago in Oakland Gabon of Africa. Now, why? That's significant is that the uranium, if you go back in time far enough, It actually enriches itself naturally.

So the fissile component, uranium 235, which is what the main source of heat is in a freshly loaded nuclear reactor, it's only got a half life of about 700 million years. Whereas uranium 2 38 the main component of uranium, it's about 99 a and a third percent of all uranium uranium 2 38 it's got a much longer half life. It's about its half life is about the age of the earth at around 4.5 billion years. And so the uranium 235, it decays faster. It's got a shorter half life. But if you go back in time, it enriches faster.

So if you go back about two billion years, natural uranium would have had a uranium 2 35 enrichment comparable to what we have today in commercial nuclear fuel about 5% and at 5% enrichment. Just natural water is enough to moderate neutrons that are created in vision to make it go critical. And we know that that's actually what happened in Oakland Gabon because we see all the fission products, the terminal fission products as the as that spent nuclear fuel literally decayed back down into dirt. And we know that based on the ice a topics the Aisa topics are the distribution of neutrons that you have in the element.

You'll have an element of neodymium which has got a fixed number of protons, but it can have different numbers of neutrons and the distribution of the element. In terms of those icy topics, how many of those atoms have so many of those neutrons. It actually matched with vision as opposed to what you find everywhere else on the earth. And it was a superposition. Or are you adding that to a little bit of the natural and a little bit of the vision? And that's what you have in the dirt. So we were able to see how does that the earth allow these materials to diffuse and propagate through the earth to the extent that they're able to if you have spent nuclear fuel on the ground.

And so we could see where it migrated to a large extent and where it didn't and what kind of controls and what kind of geology would be needed to keep it safe. And so that's what we actually have in the in the waste isolation pilot plant in southeast New Mexico, It's a licensed geological repository for trans organic waste where they receive both contact handled and remote handled trans organic waste. And so it comes down to just not trying to reinvent the wheel, just just following the model that nature already gave us.

So in other words, what you're saying is that this uranium has decayed in a way in history that we so we can see how it will decay in the future. And so we know where in the world that that that kind of process will happen safely. Is that, is that how it works? Um I think so that's not the way that I would have put it. Um We know what the enrichment of uranium is as a function of time going forward in time and going backward in time. But because we were able to see that there was a natural nuclear fission reactor that occurred deep underground, were able to see how spent fuel behaves over billions of years when it's buried in the ground? Perfect.

Well, let's move on to this question of whether or not renewable energy is nuclear energy is renewable and clean. Why do you think nuclear energy is considered clean or renewable by some people and not by others. So it comes down to what is the definition if you're gonna call it renewable. You're gonna say, what is renewable? What makes it renewable? If geothermal is renewable, the nuclear absolutely is renewable. Geothermal is nuclear just transformed that the majority of geothermal energy actually comes from the radioactive decay of all of the primordial radio activity in the earth, which primarily is uranium thorium and potassium and the and the decay products.

So geothermal is a renewable, then technically nuclear uranium already is in that sense. However, if you make a different argument, if you say renewable is where you, you spend a lot of energy and you generate a lot of waste products to make an energy extraction system and then once you've made that energy extraction system, it will passively be given energy safe from either geothermal or from solar. And you say that's what it means to be renewable. You can spend as much energy and generate as much waste as you want.

As long as once you've done it, the the the, the heat energy is free or the energy to make the electricity is passive, the nuclear would not fall under that category because you, you do have to, once you build the extraction system, you will have to refuel that that core, uh, say every two or three years. And so it doesn't meet that. But the source for geothermal being the same as nuclear kind of implies that if you're looking at something that's going to be more long lived than the sun nuclear fits that bill, nuclear will be around longer than the sun.

Every piece of dirt on average has about three parts per million uranium and about nine parts per million thorium. And the uranium it's got a half life about the age of the earth. So that when the sun goes red giant in about five billion years, the uranium still be here, half of it will be gone sure from radioactive decay, but very little of the thorium will have decayed. It's got a half life, that's about the age of the universe. So the thorium can be around a lot longer. And what's what's interesting though is that right now, natural erosion of of the mountains.

It's it's taking little bits of uranium from the granite and it's just dumping in the ocean. If we were to passively extract uranium from seawater, you don't have to dig a hole anymore. And some of the latest research claims that we can do this in a way that's cost effective. So that nine times the annual electrical needs of the United States is just being dumped into the ocean from natural erosion and it's just continually plating out year after year. If we were to use that, you know, then it becomes entirely sustainable.

Especially if we, especially if we started to recycle and started to use depleted uranium in our fuel cycle or something like that. So depends on how you define it. But the way that I would define it, I would say, Yeah, it does qualify, but it depends on how you define it. You mentioned there a little bit about recycling. How is science starting to find ways to recycle uranium and nuclear energy. So that's an interesting topic. So recycling was originally invented in the United States and uh we went away from it trying as an attempt to uh promote nonproliferation and that failed miserably.

But if you recycle it then you all of the benefits that come from recycling or there you don't have to dig more uranium up. You don't have to mine it, mill it, process it, you just recycle it and you can literally iterative li do that many, many times When you when you take a nuclear core even though that will last you say two or three years, you've only used up about 5% of the energy that's there and you can keep reusing it. And what really becomes attractive is if when you when you recycle that you take the uranium and the plutonium that was still there and the reactor at the time that it's that is spent and you mix that with depleted uranium and and a breeder reactor recycling approach, then all of the depleted uranium that we made in the past can now be turned into electricity and we wouldn't need to dig another hole for for potentially many centuries while we're developing stuff for the seawater or we could do the seawater and desalination and those kinds of things with it.

But with recycling it just makes that, what's already a small footprint, even smaller still, which is I think the direction we all want to go. Yes, this, this footprint is really important point. And so I wanted to ask a bit about why nuclear is considered clean and environmentally friendly. That's a great question. So it let's look at the definition to be clean and environmentally friendly means that you get a large amount of energy for a very small amount of impact. So small land use, small pollution, small waste generation.

That's what nuclear is. When you look at how much waste is created, how much land is used, how much mining and materials are used to get a certain amount of energy. So for a solar panel it takes a lot of materials, a lot of energy, a lot of mining, a lot of milling to make a solar panel. And then it only gives you a certain amount of energy. It's not a lot of energy that you get from a solar panel relative to the amount of energy that went into creating the solar panel with nuclear, it's just the opposite, it's got an enormous energy density.

So you get a huge amount of energy out for what's a small environmental footprint in terms of how much material you needed for the fuel and for building the nuclear power plant and all of the infrastructure for the mining and milling the entire fuel cycle. And when you look at that fuel cycle for other energy sources, what you find is that nuclear is the smallest, the smallest of the total amount of materials needed per energy extracted. And so in that sense, if that's how you define it, then nuclear becomes the most environmentally friendly.

If that's the definition that you use, given what you've told us, why are governments not building more nuclear power stations? What are the concerns from the general population or from governments about going ahead with building nuclear power stations? And what could be the opportunity there? So I think there are three things, uh, and one of them, I would say the biggest one it comes down to the radio phobia is, as I pointed out earlier on, there is this this petrifying fear that some people have of radiation and they're not likely to vote for somebody that's not going to accommodate that very strong visceral reaction that they have.

We vote for people that think like us. And if you think that nuclear is bad and evil, you're more likely to vote for somebody that thinks that nuclear is bad and evil. And when you vote for that person, that person is decision maker and they can make it very difficult. And when you have people like that being elected into office, then the predictability of the regulations becomes tenuous and it gets hard to find investors. If the there's political instability in a certain technological field. And so that's a large part of it, Another part of it is just the cost and scheduling.

Uh, we haven't been building reactors in some time and so we've lost a lot of the expertise that would be needed to keep the cost down and the scheduling type. Now, before we turn to some of our members questions, I have a question really about nuclear nonproliferation because I know that's a big focus of your research. How does your research actually address this? So I do in this lab I'm in right now. We do thermal luminescence, optically stimulated luminescence electron, para magnetic residents and gamma ray spectrometry.

And with all of those technologies, specifically the first three, we are able to take just common building materials and turn them into gamma ray cameras into gamma ray spectrometers. And so we literally are able to reconstruct the radiological history of any nuclear material anywhere in the history of the earth, even at nuclear facilities, the United States doesn't even know exists because the sheetrock in that wall could become a gamma camera, the tile on the floor could become a gamma ray spectrometer using this technology.

And the reason why this, we're developing this, why we want this to be robust is that when we're able to demonstrate that this is viable, it's deployable and it's reliable, then that becomes a real motivation for a bad actor to not try to hide their intent to break out and generate nuclear weapons, the reason why that's such a big deal is if somebody's gonna start generating nuclear weapons and they're not gonna hide it, that means the diplomats can start addressing that. They can say, why do you think you need nuclear weapons? Let's deal with that.

Let's deal with why you think you don't have the security you need. And let's make sure that you have that. So you're not generating nuclear weapons. Because if the diplomats don't get a chance to deal with it, eventually the military will, and so by having a robust anti uh covert mechanism to make sure that nobody thinks that they can hide it, then they're not likely to hide it. And if they're not likely to hide it, then then that's where the diplomats are able to do their job and and help keep us safe.

Can you just explain a bit more about how that technology works when you say you can turn a wall into something that can detect radiation, how does that actually? How does that work when you, when you look at a crystal, if you look at a crystal, if you look at the electrons, the way that they're distributed around the crystal, they form into these bands basically comes down to quantum mechanics. And when you when you apply the laws of quantum mechanics, those valence electrons are going to have certain energy levels that are available and it's due to the periodicity, they have to overlap the wave functions of those electrons.

They all have to overlap. And the periodicity causes these bands. You have the valence band and then the conduction band for an insulator. The conduction band would be empty. And the valence band is where all the electrons are. Now. Those bands are created from quantum mechanics assuming periodicity. But in any kind of crystal that you have there are going to be defects. And whenever you have a defect, you no longer are required by quantum mechanics to have that same band structure. So you can have energy levels that are above the valence band, but below the conduction band.

And these become traps. It's a place where you can trap an electron or you can trap a whole basically you can rip an electron out and leave what's basically a positive charge. And the process of doing that putting electrons from their native valence state up into these traps is done by exposure to ionizing radiation. So the more ionizing radiation that you give a material, the more energy that's going into ripping these electrons off this ionization and putting them at these traps. And if you can count the numbers of electrons or holes in the material and calibrate it, then you can measure the dose so that what we've done here is turned basically everything that's not a conductor and everything that's not wet is now a radiation detector.

And so by doing does depth profiles, you can do gamma ray spectrometry and by doing a raise does symmetric material like on a wall. You turn that into a gamma ray camera. Thank you for explaining that it's for a layperson. It's quite challenging to understand some of the science but I think you explain it so incredibly well. So thank you very much for doing that. Before we move on to some of our members question robert, I just have a question about your take on the EU's decision to define nuclear energy as green and clean.

What's your take on that? Um, I think it's entirely consistent. The international panel on climate change, I believe it was their 2018 assessment said that we have to double the amount of nuclear that we have in order to hit our climate goals not gonna happen without nuclear and we need to increase it and given the environmental friendliness and the the low impact that nuclear has, it really makes a lot of sense. The point is is that you're not gonna be able to do solar and wind for 100% of the grid unless you have a base load like natural gas or nuclear.

You know when the winds not shining and the sun is not sorry, when the wind is not blowing and the sun is not shining, you either need to have batteries or some other kind of base load generation right now the battery technology isn't there to deploy in a dispatch able way but natural gas and nuclear are so you can supplement wind and solar with, with nuclear or natural gas to enable you to use those, But you're not gonna be able to have 24/7 electricity without some kind of a backup for wind and solar.

It's just not gonna happen. Thank you for that. So let's take some of the questions from our members now. And I'm going to go to the first question, which comes from Laura. Laura's question is about why there is this hyping up of fear around nuclear power plants. Her question is really around why is it that there is this hyping up of fear and where is that coming from? Who is actually benefiting from that? Because she mentions that she's read quite a lot about Fukushima and it sounds like that the impact that she's read about is far heavier than you suggested.

So who's benefiting from creating this fear? Why is that happening? I've heard a number of theories and my favorite actually comes from a guy named Malcolm Grist um, from Imperial College and he had some really insightful things that I thought was probably the most poignant. Um, one um, there were some early on when, when the fossil fuels were potentially being supplanted. Uh, there is some evidence apparently according to him that they started this, recognizing that, you know, the only thing that nuclear was displacing was fossil fuels.

And so they needed to have a counter narrative to what was taking over at the time. However, uh, that's not really the issue today. What he says, the issue today is is that you have apparently in, in our species, you have some people that think common sense. You know, they think from their gut, they think emotionally. And then you have other people that become scientists and engineers who tend to be more empirical. They need proof. They need to be able to see it, touch it, smell it, feel it. And then they'll assess it.

And and those are the kinds of people that become scientists and engineers. And what he argued is that those are the people, the empiricist are trying to talk to the common sense, people using empirical language that the common sense people aren't necessarily ready for. For example, one of the examples that he gives is a nuclear waste, he says that uh, an engineer would think all right, so we have a unique waste products. We've got to handle it in a way that we mitigate the unique properties of that waste because it's, you know, it's got a special chemical or it's got a special rare earth or special metal or it's radioactive.

And so for the radio activity, the easy thing to do is, oh, well, we'll just, you know, it came from nature. You know, the radio activity was in the earth. We just put it back in a way that is not going to hurt anything in the time that they're the same thing we do with any other waste product. You try to put it safely in a location that's not gonna cause any further damage. And so because of that, because you recognize the science dictates that's the best way to do it. The most cost effective way to remove it from the biosphere.

Uh the, you know, the engineer would say so what we're gonna do is we're gonna dig a hole in the ground maybe half a mile deep and put it there. But then somebody that that that is more on the emotional way of interpreting uh their environment would say. So you're telling me that this is stuff, you can, you know how to handle it, you can do it safely and it's not something to be afraid of, but you have to dig a hole, you know, half a mile deep and stick it down. You know, that doesn't make sense.

If it if it's really all that easy and safe, why you got to dig a hole, That's that deep? You don't gotta do that with anything else. That doesn't make sense. You know, I don't think I trust you anymore. What aren't you telling me? I don't trust you? And that's that was his argument and that seems to make the most sense to me. There are other people that have argued similar or or even alternate theories as to why that's the case, I think that for me personally, I have actually witnessed in the past three years.

What I think is a very good analogy and that's that three years ago, I don't think I would have been able to find anybody that would say that vaccines are bad. And yet now we have people that say unless you can show me a vaccine with zero risk, I'm gonna say it's too dangerous and I'm gonna say, you know, start and you can there are conspiracy theories and there are entire social movements that now believe that vaccines are bad, but you know, they save lives. You know, I mean they're not perfect.

No, you know, there is no such thing as a zero risk solution. But if you look at the risk benefit, it's like, you know, a cured polo, right? It can take a disease that has like, you know, 5% death rate. My father died from covid, right? If he had the vaccine. Um, the point is, is that once you get that into that narrative, into a social group, it could become rooted with uh there um, their entire interpretation that's actually a great segue into anna's question, which is what can we actually do to combat radio phobia.

So what the experts all say is that you need to socialize the facts. I would say it's the same kind of thing that that the same approach to combating radio phobia would be the same approach to anti vax unless it comes from within that social group and a charismatic leader from within that social group is willing to champion it. It becomes very difficult because the people in those social groups will listen to those thought leaders, those charismatic leaders, that that contribute to the narrative of that social group.

And so I I personally, for example, I did a Tiktok channel. My students all said that they've been saying some, you know, an influencer needs to do this, but the students didn't do it. They've been doing these research projects on it and none of them did it. Until finally, I got convinced that that I should do it from a number of people that have been complaining about it too. Amazing. But that does help. I think it's about socializing the facts. We're going to move on to the question from Simon Simon's question is given, it takes time to build a nuclear power station.

Are small modular reactors a better solution. So they're really exciting. Um the small modular reactors are exciting. So even if we were to to build like the large ap 1000 or something like that, what we found is that because we been so long and not doing it that that that we have scheduling and and cost overrun issues that occur with that. But with the small modular reactors, some exciting things change by using new fuel and new designs, the exclusion zone remains within the fence. So that exclusion zone means if you had a nuclear meltdown, you still would want an offside evacuation if you had any of these 1970s designed nuclear power plants that were using today, like Fukushima was.

And so you still would have an evacuation. But hopefully we'd be much more calm and collected about it so that we're not killing people by the evacuation. The small modular reactors. The exclusion zone stays within the fence so that even if you had a meltdown and most of them are, a lot of them can't even meltdown. Uh that that the the worst that would happen is that the radio activity stays within the fence at the dangerous levels. And then the workers who have training and know how to deal with it are the ones who are addressing the problem.

And so the small modular reactors have that benefit. I mean, that's probably the that was really the only a loss of life from Fukushima was the offsite release and the resulting evacuation that followed with the small modular reactors. You don't need that. But then you also have the benefit with the small modular reactors that they are by design able to replace the heat source from a coal plant. So, you have all of the electrical grid interaction needed at a coal plant. If you remove the coal plant, you could just replace that with a small modular reactor and so start to just completely replace coal with the small modular reactors at the right power levels.

So they're really exciting in that sense, in their ability to address climate change and sustainability. I know one of your areas of expertise is around emergency response and prevention of accidents. And Monica's question is how effective have the countries with reactors become in preventing accidents, accidents since Fukushima and Chernobyl? So the biggest ones, So Chernobyl, I mean, that was just like uh, probably not even worth discussing. It was just such a gross injustice in terms of the everything that was done that went with that.

But when you look at three Mile Island and you look at Fukushima and you look at more modern designs that meet our safety and security standards. Uh, a wealth of lessons learned has occurred as a result of those to make sure that all of the mistakes that were made, there would not be repeated. Um, and so there were a large, large number of changes that occurred and probably the most profound is in the new design. So not just in the current fleet, the current fleet had to make a number of modifications.

The reactors that we have now, but the new designs have addressed all of those. So, I mean, it's just technology is just improving in leaps and bounds in some very impressive ways. There's a lot of really exciting designs that are out there, lisa has a question, I think is in all of our minds right now is if a hostile agent gained control of a power station, could they endanger people? So, I mean, yeah, I mean, but the biggest danger for example, probably let's take it to an extreme, let's say that they were to hit it with a nuclear bomb.

Uh What ends up happening with with that is that the blast is what kills people. It's not the radiation, the radiation only kills people that are right next to the survival zone, right outside the blast where the dose gets high and then it's still potentially survivable if you have medical attention, if a person got in control of a nuclear power plant, I would prefer that over getting somebody taking control, say over my water supply. Um it would be very difficult to get a modern nuclear power station to melt down and actually hurt somebody because of the containment.

Uh it would be very easy to get into the food supply or something like that and hurt a lot of people. And so uh it is possible to do damage at any facility, any industrial facility. If you took control of that, you could hurt people. Uh Me personally, nuclear is probably much better than for example, an oil refinery or you know, a cyanide plant or something like that. Like what happened with call India, you can do a lot more damage with a lot of other facilities than you can with nuclear. And but yeah, you could hurt people if you if somebody was able to get in there and overcome the security.

One of the nice things about nuclear is that you have tight security and armed guards unlike many other facilities. So anna has a question about the banana equivalent dose. She says, do you think the banana equivalent dose the bed is a good way of bringing publicity to the relative danger or lack of danger of nuclear waste? Um It could uh so if you if you look at cell biology, you actually are required to have potassium in your in your in your body, in your blood. You have to have a balance of this sodium and potassium to get water in and out of cells.

But potassium is naturally radioactive. Uh If you if you look at the dominant gamma component from spent fuel, it's from cesium, cesium 1 37. But potassium 40 naturally occurring potassium has a higher energy bait, higher energy beta and a higher energy gamma than you get from cesium. And that's what's inside of you and bananas give you that. Uh And the funny thing is is that your potassium content scales with muscle. So a large muscular male. Uh they might like they might get say 40 millirem a year in radiation dose or as a small petite female, she might only get 10 mg per year because of the potassium content and you get that from bananas, you get that from avocados, you get that from a lot of different uh plants, but it's essential to life.

And so it could, I don't see anything wrong with it as long as it's accurate, Elliott has a question about how the media is portraying nuclear energy. He says, what do you think about the portrayal of nuclear energy in the new media today? Is it largely accurate? Or do you believe it's sensationalized? Oh, just the opposite. The research has shown that for example, the new york Times has been overtly discriminating against yucca mountain. There was a secular journal article that came out that said when they present the facts, they'll only present those part of the facts that have a negative image that that that portrayed yucca mountain is a bad thing.

And so uh in that sense it's been extremely biased. But again, it other literature has shown that it's actually become part of our ethnography so that nuclear waste has become like a term like the boogeyman. It's this evil thing that that that that that you can threaten people with that actually can evoke a visceral reaction. Even though when you look at the science, the science is actually kind of exciting and it's interesting and it shows how you can do it safely and that, you know, you just don't reinvent the wheel, do it the way that nature did it now we sort of talked a little bit about how some countries have really changed their use of nuclear and have become much more reliant on nuclear for their energy needs.

Whereas other countries like Germany have decided to get rid of their nuclear power stations. And erin has a question about France and he says, can you add color to how France has been able to transform its energy and its support from society for nuclear? I think this comes down to again and to narratives um France. They've done a really great job. They, when the United States quit recycling France said, you know, we like recycling, recycling is good. Um and France recognized that it gave them a large amount of energy independence.

And as you can kind of infer today that energy independence can become a national security issue. And so when you're able to have a great deal of national security by having a diverse energy supply or an energy supply that's not reliant on unpredictable nations, that gives you a large amount of national security. So by being able to recognize that that nuclear energy as part of their national security, which gives them stability, which gives them, you know, uh price, predictability and and very good things like that so that you can plan and uh and and and not only feel safe today, but feel safe that you're gonna be okay tomorrow by being able to to communicate that to their public, I think that that was a large part of it is that they were able to to communicate this is actually really important to to all things you call french because you need this energy, you need it to do basically everything that you do.

Um you know, you can't do medicine, you can't do transportation, you can't do communication, you can't grow, I mean it is just essential to everything that we do. Anna has a question that follows on from this, which is in which countries do you see nuclear power stations popping up more in the future? Um I do have hope the United States there is hope uh that would be in the form of vision batteries. I think vision batteries are gonna play a big role in the future that these new micro reactors. Um but the biggest hope in my opinion at the moment is china.

Um China is not giving into radio phobia and they're saying we need more energy uh and energy is essential to our national security, to our future political goals to pretty much everything. And so uh china is poised to take the lead in nuclear science and technology uh and with their new reactor designs that they're coming up with that they can start selling them. I mean Russia has already been selling theirs, but I think china is poised to take the lead maybe Russia after that. If the United States doesn't start taking the lead, Then it will definitely, in my opinion, it would be Russia and China with China 1st.

Well, we only really have time for one more question. So I'm going to combine questions that we've had from Lorna and Luca. The question is really around the types of other energy sources that could gives a similar level of energy to nuclear. Um is there a combination of renewable energy technologies that can generate the same amount of energy as a nuclear power station? And is solar an answer to that question? So solar is good um wind is good. Um there there are a number of liabilities there, it's a large amount of energy that's required to build the solar panels and that generates a large amount of waste.

Um and so there there there there's not a lot of potential for them to be able to replace themselves. Right so right now we use fossil fuels to make them and then we just use the electricity but long term they would need to not only make electricity but make the energy to replace themselves which makes them much more inefficient. Nuclear is able to do that, fossils, fuels able to do that as long as we were able to continue using fossil fuels and so all of that there there is no zero risk, there is no perfect solution.

Everything has its pros and its cons one thing that I think is important to look at when you're answering those kinds of questions is the need for diversity uh like with your retirement package. If you rely only on one energy source, like let's say Ireland or not Ireland Iceland uses geothermal. If there was a plate tectonic motion that occurred rapidly and all of a sudden the country was flooded with, I mean, I don't know that this would occur, probably wouldn't occur. But the point is, is that when you rely on one technology, anything that that technology relies on, if that goes away, potentially you're gonna be able to take down the whole thing.

So whether it's in the supply chain or the waste disposal part or the actual operation, there are a number of things that you have to rely on for that to go through smoothly. And so there's this old rule for mechanical engineering that if you have a system with lots of moving parts and each part has a certain probability of failure, then the the probability of the whole thing going increases with the number of parts that you have, the more parts that you have that you rely on, the higher the probability that something is gonna go wrong.

And so if you're not relying on a single linear chain for anything, then that that gives you a large amount of stability because one thing could go out. But you've got a number of other things to fill in and and address that. So you never want to rely on one type of energy or one type of material or one type of process as a general rule. And so you do want a diversity. And that's what the energy experts say is healthy. So it's not just all nuclear unless you can really make nuclear really diverse.

So that you're not relying on one country to source it. You're not relying on one country to manufacture the fuel and then the cladding and then the structure and the pressure vessels or whatever. You've got a large array of competing factors that are trying to get that same market business. Um, and that's the best way to go. Unfortunately, that's all we've got time for today, robert. Thank you so much for joining us here in The Garden and for answering all of our tricky questions, a really important topic.

And we're thrilled to have you here. Great being on. Thanks for having me and thank you to you. Our members for joining us here today too. I hope you enjoyed today's talk and you learned something and your curiosity was piqued. We will see you again very soon at your next Garden gathering. But until then stay curious.

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