Nuclear Physicist Explains - What are Thorium Reactors?

what are these thorium reactors hey there it's  Elina your friend nuclear physicist and today we   are finally discussing about the thorium reactors  I'm gonna be focusing this discussion on thorium   as a fuel and specifically for the lftr design  we're gonna be breaking this video down into   seven categories discussing about fuel abundance  safety economics efficiency waste proliferation   and the current status of the lfdrs around the  world before we will get started let's explain   what the thorium reactors are so lftr as I said  liquid fluoride sodium reactors are basically a   molten salt type of reactor meaning that the fuel  inside the core is actually in a liquid form in a   salt kind of formation that circulates inside the  core it is hot and acts as a fuel and coolant at   the same time meaning that the heat from this  liquid fuel that is circulating inside the core   is being transferred to the heat exchanger and  therefore being transferred to the the rest of the   components and electricity is produced similarly  to any other type of reactor so this is sort of   the biggest difference from the typical reactor  types that we are discussing where the fuel is   solid in fuel assemblies that are structured in  a specific geometry inside the reactor so here we   have kind of a different composition that provides  potential benefits and also some disadvantages in   the molten salt reactor type and molten salt is  sort of a bigger category under which thorium   reactors lie because you can have Modesto reactors  having for example uranium fuel not necessarily   only thorium however it has been proven that  thorium reactors better work with molten soil   designs therefore these are the ones that we're  going to be considering in the rest of the   discussion so first off what is Thorium and how  is it different from uranium so Thorium in itself   is abundant on Earth in the isotope thorium-232  which is the one that is the most abundant and   the isotope itself is not fissile meaning that it  will not fission once a neutron heated like for   example the uranium-235 does so its behavior is  similar to uranium-238 which will capture Neutron   and basically transmute into another element  so in the case of thorium-232 when a neutron   hits it it will capture the neutron transmute into  productinium-233 that will Decay into uranium-233   and then the uranium-233 is actually a fissile  material similarly to uranium-235 meaning that   if a neutron hits it it will actually split into  two smaller atoms producing energy at the same   time which is efficient energy and hence how  we have energy production from thorium reactors   therefore thorium as itself is not being used as a  fuel but is being used as a let's say step before   the fuel is produced inside the Reactor Core  there's two ways that can be produced uh the   two uranium-233 can be produced inside the core  or outside and then placed inside the core as a   fuel for the thorium reactors so let's get into  number one which is fuel abundance we recently   hear that thorium is much more abundant on Earth  than uraniumase and this is partially true so when   people talk about the abundance of thorium they  usually refer to the crust of the earth and the   presence of thorium there where it is true that  thorium is around three times more abundant than   uranium is however these discussions usually don't  take into consideration the uranium that exists   under water the reason why this is not taken into  consideration it is because as of now we don't   mind uranium that exists underwater because it is  not economically efficient however in the future   once the uranium let's say abundance that we have  on the crust of the Earth is going to reduce this   technology mining uranium from the oceans might be  economically more attractive and therefore we will   be able to do that even though thorium is more  abundant on Earth on the crust of the earth as   of now and it is more environmentally better to  mine than uranium is its abundance is not that   significant compared to that of uranium however  the abundance of uranium underwater is around 80   000 times more than that of volume which is pretty  much non-existent therefore it is important to   understand the abundance from all the aspects  that it concerns and to make the decision moving   forward as to either if one wants to switches  for thorium or remains with the technology   that is already mature and try to make it more  economically competitive while mining uranium   from the Seas moving on to the second point  with regards to the safety of the lfti reactors   and these safety features are more associated  with the multitude reactions in general and not   so particular to the thorium fuel itself however  since the volume is going to be probably used with   this type of reactors it is important to provide  this information as well so multitude reactors in   general have a lot of safety infinite features  which make them very attractive as a reactor   design to be built in the future some of them  are for example an inherent negative reactivity   coefficient meaning that the reactor by its design  doesn't allow the reactivity the power to go high   and uncontrollably and cause for example a nuclear  accident in case of let's say things go out of the   operational conditions which is very positive and  it is pretty much what the generation 4 reactors   are having as one of their goals for the future  to have this passive safety features that don't   really need anyone actively pressing a stop button  or handling this whole situation another important   thing to mention is that compared to for example  the pressurized water reactors that we use now   these multicent reactors don't operate under high  pressures therefore they are more safe in a sense   and things that relate to high pressure designs  are not relevant to these kind of reactors hence   problems like that would not be an issue in  molten salt reactors another thing to mention   is the fact that fission product buildup is not  also in concern in these reactors as a lot of   future products can actually be extracted from the  molten salt while circulating and the reactor is   in operation as in for example the Xenon which is  a poison as we call it inside the reactor core and   can actually create a lot of let's say imbalance  inside the reactor and power fluctuations which   can cause problems during operation or accident  conditions hence it is an yet another good safety   feature of this type of reactor sort of a  disadvantage when it comes to the safety   aspect of all the salt reactors is the fact that  their melting temperature is quite high around   five to six hundred degrees Celsius therefore  under normal operational conditions usually   operate at quite high temperature meaning that  it plays for example of an accident where we have   no electricity therefore no heating provided into  the reactor for a prolonged period of time there   is a danger and there is a risk of the molded salt  core pretty much freezing because the conditions   have dropped in a temperature below the melting  temperature of the of the fuel itself this of   course can cause a lot of problems from destroying  equipment such as pumps or heat exchangers through   which the salt is Flowing or creating delays  and even more budget problems in order to be   startup again moving on to the third aspect of  these reactor designs and here we are going to   discuss about the economics so typically for light  water or pressurized water reactors which are the   reactors we are currently using the utilization of  the fuel and the efficiency in this utilization is   around one percent of the fuel that is being mined  and the fuel that is being basically consumed and   burnt inside the reactor meaning that we  typically mind uranium-238 then we have to   enrich it into not such high enrichment percentage  this enrichment is the one that's mostly used to   fission inside in the reactor and therefore the  rest of the fuel is basically being discarded as   waste without really being used however in thorium  our enrichment is not necessary so this of course   benefits economically the reactive design because  enrichment does cost quite some as well as the   fact that because enrichment is not necessary  pretty much all of the fuel or the thorium that   is being mined can be used as a fuel inside the  reactor increasing significantly the efficiency   of these reactors to utilize their fuel it is  important to mention that but even though no   enrichment of volume is necessary as we already  mentioned and as it is usually mentioned when   discussions happen around thorium reactors it is  important to know that a fissile material is used   and it is necessary to be used in order to start  up the reactor for the necessary neutrons to be   produced to let's say be captured by the thorium  and then it being transmutated into uranium 330.   into uranium-233 that is a fissile material and  can therefore sustain a chain fission reaction   therefore the fact that no enriched material needs  to operate a thorium reactor is not true but the   thorium itself or the majority of the fuel itself  is not necessary to be enriched so the enriched   amount that is necessary is quite small another  important aspect when it comes to the economics of   the molten salt reactors is the fact that since  this is a molten salt core there is not a high   costs associated with fuel manufacturing and fuel  fabrication such for example that there are in the   kind type of reactors that we are using where the  fuel is solid first of all need to be fabricated   into pellets then put inside the the cladding the  fuel assemblies we have to basically construct the   spacers inside the core that the fuel assemblies  are sitting inside there's a lot of fabrication   going on which of course adds additional costs in  the moldasort reactors you can sort of eliminate   all of these costs by basically having a core  which is just filled with molden fuel which   is not So Much reprocessed from the one that you  mined from from the mines and the last important   aspect when it comes to the economics of the  Modesto reactors and specifically the lftrs is   the fact that refueling can happen online meaning  why the reactor is operated new fuel can be added   which means no downtime for the reactor which as  we know is one of the most expensive ways that   the nuclear industry loses money by having the  reactor shut down for any sort of Maintenance   or refueling so here we eliminate this let's say  disadvantage while having refueling online having   no losses when it comes to financial aspect so  moving on to the next aspect of our discussion   and this is the efficiency of the lftr reactors  and generally mold and salt reactors as well and   here one very good and positive outcome of  a multi-in solid reactive design is the fact   that since there's no structural components as  we discussed before no cladding no spacers no   fuel assembly that could possibly capture neutrons  and therefore reduce the efficiency of the reactor   and the amount of nutrients that can actually  cause fission in a multi salt reactor this is   not a problem since the whole core is simply  filled with molten fuel so all the neutrons   that exist in the core are pretty much hitting  the fuel and fissioning the fuel existing in the   core hence producing electricity in a let's say  a more efficient way and not captured left and   right from materials that are not supposed to be  efficient it is commonly known that thorium is a   very good fuel for slow Neutron fission and what  that means is that typically uranium-233 which   as we explained is the byproduct of thorium-232  is more efficient when the neutrons have slowed   down however there is a benefit and disadvantage  to having a slow let's say nutrient speed and this   can cause the a breathing ratio meaning that  how many neutrons are produced compared to how   many nutrients are consumed being very close to  actually being efficient or not therefore usually   people opt for fast Neutron Spectrum meaning  that the neutrons that are going to be produced   are more than the neutrons that are going to be  consumed and in the fast Spectrum this is more   probable and more possible however combining  a fast Spectrum with a thorium fuel is not the   most Optimum therefore choices such as uranium and  plutonium are being chosen instead and moving on   to the next aspect and that would be the waste  that is produced from thorium reactors and here   since thorium is an element that has a smaller  atomic number than uranium meaning that we produce   all kinds of elements in the periodic table that  are below the Thorium in the periodic table hence   we do not produce the transhumanic elements  which are typical for the type of reactors   that we are using now and which are also the ones  that are contributing to the very long times that   it takes them to Decay into radioactivity levels  that are similar to the background hence they need   to be stored for hundreds of thousands of years in  geological repositories the ways that we are going   to be getting from thorium reactors is actually  going to be less Radioactive in the long term   and that means that their storage will probably be  in the range of hundreds of years and not tens of   thousands of years which is a very good aspect of  course however the waste will be in the short term   much more toxic and more dangerous than it is from  uranium nuclear reactors and the reason for that   is for example the fact that the uranium-233  which is basically the fuel that is used for   thorium reactors decays into elements that are  highly radioactive emitting gamma radiation which   as you might know is very hard to Shield yourself  from since it penetrates through pretty much a lot   of material out there and therefore it is quite  hard to handle this Fuel and basically protect   the workers and the environment from this gamma  radiation it is also important to mention that   it is quite easier to store solid fuel such as the  one that's getting out of the reactors that we're   currently using compared to fuel in liquid form  especially in the fluoride form these salts are   quite corrosive and are very aggressive when it  comes to their contact when it comes to the water   therefore they are not suitable for permanent  geological repositories as the ones that are being   developed now for the fuels that we are currently  have as spent and stored in the the storage pools   therefore we would need to develop some extra  technology and some new let's say ways to store   this fluoride molten salts even though for the  short period of time that they need to be stored   moving on to most probably the most important  aspect of discussion for the thorium reactors   and that is the proliferation issues that  are associated with this type of reactor   even though once you Google about Thorium  reactors the let's say most important advantage   that's being portrayed out there is the fact  that they are so strongly non-proliferation   designs and that is true partly when it comes  to the fact that inside the reactor while the   fuel is let's say the tholium is transmitting  to uranium-232 hence the uranium-233 and so on   the gamma radiation is quite High which as we  said requires shielding and because there is   high gamma radiation they are hard to handle hence  they are hard to like still let's say this type of   fuel and handle it in order to make bombs and  keep it from not melting by itself because of   how high the temperatures are from the radiation  that it is emitting however this is not the only   problem when it comes to non-proliferation it is  important to mention that the thorium designs and   the thorium reactors that have been designed  in order to be breeders meaning that in order   to be sustained and produce their own Fuel and  not needing some fissile material in order to   operate have one very important feature in order  for them to be made feasible and that feature is   the fact that while thorium is capturing a  neutron and transmitting into productinium   233 this productinium is basically the one that  will Decay into the fuel the uranium-233 that   it is necessary to to have in the reactor in  order for this fissile material basically to   to create fission and create energy now usually  what we discuss for the positive proliferation   issues of the thorium reactors is that this  uranium-233 has a small amount of uranium-232   inside with very high on gamma radiation  emitted and hence it's very hard to handle   steal the uranium-233 however going step back it  is important to mention that all or at least most   of the designs of the thorium reactors that are  out there suggest for the productinium 233 to be   removed outside of the core in order to not poison  the core because it has a tendency to absorb a   lot of nutrients hence it can basically stop the  self-sustained Chain Reaction one then suggests   to remove the productivium keep it outside of the  core let it decay to uranium which takes around   27 days and now that you have uranium-233 which  is a fissionable material you put it back in the   reactor and the Chain Reaction keeps going and  this is how basically the fuel is produced for   the thorium reactor types but the uranium-233 is  a perfect weapons grade material there have been   tests out there with nuclear bombs creating with  the base of uranium-233 and they work perfectly   fine therefore this is a very big tone that  is inherent to the design and the operation of   thorium reactors now it is important to understand  that even though the stealing of them let's say   fuel from a thorium reactor might not be such a  plausible case for discussing proliferation issues   the fact that the owner of the power plants  and the thorium reactors themselves have the   ability to produce weapons grade material that is  perfectly separated from the rest of the reactor   and can immediately be used to generate weapons by  nuclear energy is a very big concern when it comes   to this type of reactors and who is basically  allowed to use them and who is not therefore   it is important to mention that for example  thorium is one of the protected Elements by iaea   the international atomic energy agency because  of this proliferation concerns even though for   example uranium is not and moving on to the last  aspect of the lfti reactor types and this would   be the current status so what is happening  out there currently the biggest let's say   disadvantage that we currently have with Sodium  Reactor types is the fact that we have little   to no experience on how to operate them what  the problems are what might happen and how one   would approach it because we never really build  commercial reactors that use thorium as a fuel   even though there was an experiment in Oak Ridge  which you can read more about in the description   uh linked down below that did work on a mold and  salt reactor type we don't really have significant   experience that would give us the possibility to  say with certainty that these reactor types are   going to work are going to actually be breeders  instead of a typical reactor like the one we have   now so basically always needing new fuel to be  operational and all of the other benefits that   we're basically discussing are good in paper but  have never really proven or implemented in reality   to work another important aspect as I mentioned  in the waist section is the fact that we don't   really have a way to store waste that comes out  of a modern salt reactor as it is quite different   from the solid fuel that comes out of a let's say  typical reactor that we are currently using hence   this would add an uncertainty to the cost of  the waste storage and management as well as to   how are we supposed to do that exactly and an  important thing to mention as well is that molten   salt in itself is a quite corrosive material even  more corrosive than lead and therefore there is   still a lot of research and development that is  necessary and new materials that are needed to   be basically developed and made for these kind of  reactors in order to withstand the conditions that   they are going to be under during the operation  or basically the whole lifetime of the reactor   itself currently plenty of countries such as China  India and Canada are interested in sodium fueled   reactor types and are pursuing their own designs  and planning to work with them in the future I   know that I'm going to get plenty of comments  in the comment section asking but what do you   think about the thorium reactors I'm going to  spare you the time and give you my opinion in   this video I do think that thorium as a fuel is  very promising we have it so we might as well   develop some technology to use it in the future  however I do see the limitations that are quite   real with thorium and as long as there is no  better design than the one that we are currently   having planned to implement I don't see thorium  as if you're moving forward mainly because of   their proliferation issues that are associated  with it I also believe that the thorium reactor   types have a similar kind of philosophy and  mentality of operation as the ones that plan   to use the spend uranium fuel from the reactor  types that we currently have therefore if I was   to invest in research and development in either  of those Technologies I would much rather invest   and develop reactors that could actually burn  the spent nuclear fuel that we currently have   stored and have pretty much nothing to do with  in order to minimize our nuclear waste on planet   Earth instead of developing a whole new technology  that might have its own limitations will take its   own delays its own time and we're not sure how  promising it will actually be at hands therefore   even though I do like the idea of volume I do  believe that it is currently not the main point   of focus of the nuclear industry and the important  research and development should and will continue   on it and of course when the time is right and the  designs are in place that would basically prove   its uh safety in terms of proliferation issues  then we might as well implement it in the next   Generations to come thanks for watching this video  let me know in the comment section down below what   do you think and what's your opinion about Thorium  reactors and also let me know what kind of reactor   types would you like me to explain in the future  don't forget to like And subscribe and leave a   comment down below it's been Elina your friendly  nuclear physicist and until next time see you soon

Channel: Elina Charatsidou

Views: 623,554

Keywords: nuclear power plant, nuclear, nuclear energy, Nuclear power, Nuclear physicist, nuclear physics, physics, science, energy, radiation, nuclear reactor, nuclear waste, technology, nuclear fission, renewable energy, production, electricity, climate change, thorium, thorium reactor, uranium, Nuclear Physicist EXPLAINS - What are Thorium Reactors?, what are thorium reactors, nuclear physicist explains, molten salt, lftr, thorium fuel, liquid thorium, nuclear thorium reactor, thorium energy

Id: 148NI9j23Kg

Length: 23min 6sec (1386 seconds)

Published: Sun Dec 18 2022