TEDxNewEngland | 11/01/11 | The Future of Nuclear Power: Getting Rid of Nuclear Waste

[Music] [Music] hi it's almost eight months since the accident at Fukushima and where do things stand well there be no radiation related fatalities so far and even in the long run probably only a very small number maybe even none at all and certainly a total that will be tiny in relation to the 23,000 people who perished in the earthquake and the tsunami and yet more than 80,000 people have been forced to leave their homes as a result of the nuclear accident and with no prospect of returning anytime soon and so what we have is a human disaster if not a health human health disaster so where are we going to go from here well the Germans and a few other countries have said that that's it for them they're pulling out they don't want to go any further with nuclear power but there are many more countries China Russia Korea India and many others that have said they've really barely skipped a beat they're just moving ahead with the plans that they had even before the accident and at least 20 other countries are thinking seriously even today about entering the nuclear field for the first time and this really reflects the reality that nuclear energy is the only low-carbon energy source that is both scaleable and already generating large amounts of electricity around the world and when we look at the world's rapidly growing demand for energy 50% increase almost certainly over the next 20 years and then much more beyond that and combine that with the need for deep reductions in carbon emissions over the few the next several decades to avoid the worst possibilities of climate change it's really hard to know how we're going to achieve both of those things without a significant expansion in nuclear energy but to achieve this we're going to need a couple of things the first thing is greatly strengthened nuclear governance that's really I think the lesson that we should draw from Fukushima it wasn't so much a technological failure but it was a failure of the the things that engineers often disparage as soft things people organizations procedures institutions the things that have to work in order for these things to to be safe the second thing that we're going to need is technological innovation a technology that's already a lot safer than it was when those reactors at Fukushima were built 40 years ago needs to be made safer still as well as less expensive more resistant to nuclear proliferation and terrorism and compatible with the capabilities and the limitations of the real organizations that we'll have to build and operate these these plants the leaders of these innovations aren't going to be people like me they're going to be the people the smart the dedicated young men and women who have been entering nuclear science and engineering programs around the country for the last ten years in increasing numbers and in my observation these are a serious idealistic and practical group of people they see great engineering challenges in building and designing nuclear plants that are safer and more economic they see an opportunity to ameliorate the threat of climate change and unlike so many of the politicians that their parents have elected they actually read and understand the papers about this problem they know that nuclear energy is the only low-carbon energy source that's both inherently scalable and already generating large amounts of electricity these will be the innovators and we have today - absolutely terrific examples of what I'm talking about Leslie and Mark are graduate students in the Department of nuclear science and engineering at MIT they're also entrepreneurs and their idea is to develop nuclear plants that produce significantly less greatly reduced amounts of nuclear waste so with that let me turn to Leslie and Mark and good afternoon everyone um I'm incredibly excited to be here so right now as Professor Lester said nuclear power is at a crossroads there some countries like Germany and Italy that are moving to get rid of nuclear power entirely whereas other countries like China are greatly greatly expanding their nuclear infrastructure and also on top of all of this political maneuvering there's also a great deal of new nuclear technology being developed and a lot of this technology is focusing specifically on solving nuclear safety and waste problems a nuclear reactor is really nothing more than a fancy way of boiling water so no it's totally true so up on the left-hand side here you have the reactor vessel and so there in the core of the reactor there's a large number of fission reactions going on those generate a great deal of heat which is used to boil water into steam and then the steam powers a turbine which in turn creates electricity so for right you can think of that entire reactor core as just being a black box you could replace it with a different type of heat source and you'd still have a viable power plant now the main thing that mark and I are going to be talking about today is what's inside that black box so what reactor cores were like in the past what they are now and then most importantly what they could be in the future so right now we really only use one type of nuclear reactor to generate electricity this is a light water reactor like Leslie just explained but this hasn't always been the case in the earliest years of the nuclear industry there was a tremendous amount of innovation taking place engineers were designing reactors that were cooled by water gas sodium and even mercury and they were looking into applications for these reactors that we would consider just completely unthinkable right now like a nuclear-powered aircraft or a nuclear-powered automobile like the Ford nucleon so how did we go from this era of tremendous innovation to essentially building one type of nuclear reactor to answer this we have to go back to the 1950s after World War two the United States Navy was at the forefront of the nuclear industry they were engaged in a race with the Soviet Union to produce the world's first nuclear-powered submarine and the US Navy developed a light water reactor and they used this in the USS Nautilus and this launched in 1954 so whenever plans started to develop to use nuclear reactors to generate electricity they simply took the design that they made for powering a submarine and built it on land this is the Shippingport reactor outside of Pittsburgh Pennsylvania this came online in 1958 and became the world's first truly civilian nuclear power plant this is a light water reactor just like the one used on the Nautilus and they chose to go with this design not because it was the best technology but simply because it was the technology that they understood the most all 104 commercials power reactors in the United States and almost all of the ones internationally are the same type of light water reactor the companies that design and build nuclear reactors are only familiar with this one type of design so it's really hard for new technology to break into the industry because you have to convince all of these companies that it's worth their while to take a chance on something new so the future might not be in the United States the US has been allocating some amount of funding to new nuclear reactor designs but other countries like China have been allocating far far more even more importantly China is building a lot of new nuclear reactors so right now China has 14 operating commercial nuclear power plants and another 27 under construction and on top of that they have 51 more plants planned and then another 120 proposed so that's 212 total in China so there's a chance just with those numbers that the future might be there and not here in the US the second thing professor Lester mentioned this too is the age distribution in the industry so here's a here's a rough schematic of what that looks like and there's a big dip in the middle that was caused directly by Chernobyl and Three Mile Island people didn't want to join the industry after that but now 25 30 years later they're young people young environmentally conscious people who think that nuclear is the way to go so it's a younger workforce and then lastly the future of nuclear has more startups over the past 10 years or so in the u.s. there have been about five new nuclear startups founded and a lot of these companies are focusing specifically on solving nuclear safety and waste problems and waste in particular is a very big problem each commercial nuclear power plant produces about 20 metric tons of high-level nuclear waste each year so within the US that's 2,000 metric tons of high-level waste and worldwide about nine thousand metric tons of high-level nuclear waste each year and no one knows what to do with it yet so most of this waste is just sitting above ground waiting for a solution and that's actually where Mark and I come in so we've invented a new type of reactor called the waste annihilating molten salt reactor or the Windsor that can run entirely on the nuclear waste produced by conventional light water reactors and even more importantly it reduces the volume of the waste as it turns it into electricity so it consumes it and reduces the original wastes volume by up to 98% so whereas a conventional reactor produces about 20 metric tons of high-level waste each year our reactor produces only around three kilograms of waste each year and that's about the size of a baseball and it produces an enormous amount of electricity - so right now in the world there's about 270 thousand metric tons of high-level nuclear waste that exists we can take that waste put it into our reactors and produce enough electricity to power the entire world for 72 years and that's even taking into account increasing demands so you're powering the world for 72 years while simultaneously getting rid of almost all of its nuclear waste so there's there's a lot to like there we think so you might be wondering how we can get so much energy from something that we call waste it's actually a semantics issue what we called nuclear waste isn't actually waste at all it still has a tremendous amount of energy remaining in it the reason that we can get so much energy out of this is inherent in the design of the reactors that we use right now in conventional reactors you have a fuel rod which is made of a thin metal hollow tube called the cladding and this holds the uranium fuel pellets in place this cladding over time becomes irradiated and radiation damage can cause the cladding to become brittle and eventually break this limits the amount of time that fuel can stay in a conventional reactor to about four years but the longer that fuel stays in a reactor the more energy you can get out of each one of the fuel pellets and the four-year limit that's placed on that's placed on how long fuel can stay in a reactor limits the amount of energy that conventional reactors take out of each fuel pellet to about three percent and this is also partially partially why radioactive waste that comes out of these stays around for so long it's because they still contain 97% of their original energy so let me put this into perspective imagine that you're a hundred grad student you fixed yourself a sandwich you take a bite out of it you're still hungry but instead of taking another bite out of this you fix yourself another sandwich you take one bite out of it but again you're so hungry if you keep this up eventually you'll get full but in the process you'll create a tremendous amount of radioactive sandwich waste and what Leslie and I have figured out how to do is eat all of this leftover sandwich weighs so we got our inspiration by looking at all of these really diverse reactors that they designed in the first years of the nuclear industry one in particular called a molten salt reactor the United States built and operated two of these reactors in the 50s and 60s and they had tremendous safety features but they weren't designed to run on nuclear waste so Leslie and I have figured out a way to take these reactors and make them run entirely on waste we take the fuel that comes out of conventional reactors and remove that metal cladding and then we take the fuel pellets inside of there and dissolve it in a molten salt so instead of using solid fuel like they do in conventional reactors our fuel is a liquid and since we've gotten rid of the cladding which is what limits how long you can keep it in a reactor we can leave it in a reactor for as long as it takes to extract essentially all of the remaining energy in it this also means that the waste that comes out of our reactor since we've extracted so much more energy out of it is much less radioactive conventional reactor way stays around for hundreds of thousands of years but since we've extracted almost all of the energy out of this the waste that comes out of ours will be radioactive for most of it will be radioactive for only a few hundred years and waste that's around for a few hundred years that's a long time but it's a solvable engineering problem so oh here's a rough schematic of what our plant looks like so up on the Left you have the primary loop that has the molten fuel salt flowing through it and in the reactor core on the far left it's in what's called a critical configuration so there's a large stable number of nuclear fission reactions that produces a great deal of heat then this heat is carried over heats up steam in the secondary loop which powers a turbine that creates electricity so it's a lot like the first reactor schematic I showed you only with a different thing inside of the black box now the most important thing about this liquid fuel design is that it's very safe so in a conventional nuclear reactor you need a continuous supply of external electric power so that you can continue we pump coolant over the core to keep it from heating up catastrophic ly and that's what happened at Fukushima but this type of reactor design doesn't need that at all what we have instead is what's called a freeze valve that's at the bottom of the primary loop up on the left and the freeze valve contains a plug of the same type of salt that's in the primary loop only electrically cooled so that it's solid so if the plant itself loses electric power the plug loses its cooling and so old the salt from the primary loop flows into the auxiliary containment at the bottom and when the salt is in this secondary containment it's no longer in a critical configuration so it's not producing nearly as much heat and so it eventually cools and cools and eventually solidifies over the course of a few days and so this means our reactor is what's called walkaway safe so if the plant loses all electric power even if the operators are no longer on site it'll gradually coast to a safe stop over the course of the few days here we are so what we'd like is for people to reevaluate their preconceptions about nuclear power right now there's new designs and new people in the industry that are working to solve the safety and waste problems and what we have here is environmentally sound nuclear power that we can use to meet the world's energy needs thank you all so much [Applause]

Channel: TEDx Talks

Views: 119,070

Rating: 4.8619366 out of 5

Keywords: TEDxNewEngland, Nuclear Power, tedx talks, Mark Massie, English, tedx, ted x, Transatomic Power, New England, Nuclear, Dr. Richard Lester, ted talk, ted, ted talks, Nuclear Waste, tedx talk, WAMSR, USA, Leslie Dewan

Id: AAFWeIp8JT0

Length: 19min 1sec (1141 seconds)

Published: Mon Nov 14 2011

Reddit Comments

[u/api]

Lots of cool stuff happening right now in energy, from lots of different angles.

If you grasp the magnitude of the fossil fuel shortfall that is coming, we are going to need it all.

[u/zhandoatosl]

They have a website and they appear pretty tight-lipped about details..

They remind me of what the small group in France is doing with molten salt reactors. It appears the aims are similar.. The French group however is mostly focused on using MSRs for waste processing if I'm not mistaken.

Transatomic seems to want to lure venture capital with promises of throwing profitable amounts of electrical power and taking nuclear waste off the hands of the current industry.

They also seem to want to go the small/modular route.

Kirk Sorensen has also eyed nuclear waste as a feedstock to transmute into U233 to start up LFTRs but that would involve building a Chloride based fast reactor - something that's never been done before.

[u/DarkSoviet]

It would have been nice of them to spend more time talking about their mechanism than talking about the dumb sandwich analogy. What about the efficiency of an operating plant? Are graphite rods still used to control the reaction or does this stand no chance of runaway? In the event of a loss of cooling power, if the liquid salt is drained into the auxiliary storage, what happens to the fissile material in the heating reactor? This presentation needed more meat to it.