It seems we have finally come close to implementing closed fuel cycle technology in nuclear energy. What is it, why is it cool, and what else needs to be done – we discuss all of this in today’s video!
Russian company Ross Adam announces that it has come significantly closer to achieving what’s known as a closed nuclear fuel cycle this breakthrough could potentially resolve a major issue in modern nuclear energy and ensure Humanity’s energy Security in the near future the concept itself isn’t entirely new but for many decades its realization
Remained in the realm of Science Fiction only now does it seem that it might materialize into reality subscribe to our Channel and let’s dive into understanding what this closed fuel cycle is why it’s necessary and why scientists have yet to implement it in practice the primary fuel for nuclear
Reactors is uranium thanks to a process known as forced nuclear fishing the core absorbs a neutron becomes unstable and splits into two smaller fragments the total mass of the fragments is less than the original atoms Mass releasing energy as per Einstein’s Formula E equal mc2 furthermore more several neutrons are
Released during this fishing theoretically capable of triggering the fishing of other nuclei generating more energy and more neutrons these will cause more atoms to split creating a chain reaction while in most cases the energy stored within radioactive atoms is slowly released due to nuclear decay in forced fishing reactions we can
Control the release of this energy by regulating the neutron flows power absorbing a certain portion of released neutrons through various means the problem lies in the fact that only a few radioactive materials are capable of sustaining the chain reaction of forced fision not all uranium nuclei can do this specifically only the isotope
Uranium 235 with 92 protons and 143 neutrons in its core can sustain the reaction natural uranium contains only about 0.7% uranium 235 while 99.3% is uranium 238 with 92 protons and 146 neutrons which does not support this reaction hence most efforts spent on mining uranium ore purifying it and more
End up in vain over 99% of the product from these technological processes turns out to be practically useless waste which is quite frustrating but it’s not just about monetary considerations natural uranium reserves are quite limited utilizing only 0.7% of these reserves as nuclear fuel severely restricts the resource base of nuclear
Energy explored uranium reserves on Earth are estimated to sustain current nuclear power plants for only 50 to 100 years with an expansion in nuclear energy usage which I’m confident will happen this duration will be even shorter however it was soon discovered that waste uranium 238 isn’t entirely useless under certain conditions it can
Be converted into nuclear fuel when it absorbs a neutron it transforms into uranium 239 uranium 239 under go beta decay on average in 23 minutes one of its neutrons turns into a proton resulting in 93 protons and 146 neutrons becoming neptunium 239 neptunium on average under goes another beta Decay
Within 2 days resulting in 94 protons and 145 neutrons creating plutonium 239 fortunately plutonium 239 can also sustain a chain reaction of forced fishing serving as nuclear fuel in simpler terms by bombarding useless uranium 238 with a powerful Neutron flow we produce a valuable amount of plutonium 239 these strong Neutron flows are
Readily available in operating nuclear reactors in other words we can place a certain amount of uranium 238 in a working reactor where it turns into plutonium we’ll extract this plutonium and create fuel for a new cycle of reactor operation producing more plutonium from uranium 238 and so on to
Be precise there’s no need to specially introduce uranium 238 nuclear fuel used in nuclear power plants mainly consists of uranium 238 although the proportion of fuel uranium 235 in it is increased averaging up to 5% in essence any nuclear reactor during its operation produces fuel for itself as a byproduct
The idea of the closed fuel cycle revolves around making reactors operate on the fuel they’ve previously generated for themselves in reality this cycle isn’t entirely closed since uranium 238 is consumed during the process however considering the mountains of uranium accumulated over the years of nuclear energy existence the concept is
Undeniably promising however as is almost always the case in nuclear energy it’s easier said than done in practice things turned out to be to put it mildly a bit more complex take for instance the simple fact that ordinary nuclear reactors aren’t particularly Adept at converting uranium to 238 into plutonium
As we mentioned earlier nuclear fuel always contains some amount of uranium 238 absorption of neutrons by its atoms is generally considered an undesirable phenomenon indeed if a significant portion of the neutrons produced during the fishion of uranium 235 are captured by uranium 238 atoms they won’t be available to initiate new acts of
Uranium 235 fishing thereby halting The Chain Reaction so in the early days of nuclear energy scientists and Engineers had to put considerable effort into minimizing Neutron capture by uranium 238 one way of course is to increase the proportion of uranium 235 in the fuel and decrease the amount of uranium
238 unfortunately separating uranium 235 from uranium 238 is a non-trivial task since these atoms are chemically identical and differ only slightly in Mass just over 1% hence isolating the right uranium from the wrong uranium or enriching uranium fuel is quite a challenge while this task must be addressed to prevent nuclear fuel from
Being exorbitantly expensive it can’t be the sole solution the most successful idea was incorporating layers of a substance capable of slowing down the neutrons passing through it what’s known as a moderator it turns out that uranium 238 more effectively absorbs fast moving neutrons while uranium 235 interact better with slow or thermal
Neutrons by reducing the energy of the neutrons we simultaneously increase the efficiency of the uranium 235 fision chain reaction and decrease losses due to Neutron absorption by uranium 238 this gives us the ability to sustain The Chain Reaction using cheaper fuel with a lower degree of enrichment this works well for
Traditional reactors however it undermines the concept of a closed cycle reactors using ther neutrons which practically all modern reactors belong to produce very little plutonium per unit of burnt nuclear fuel thus making it impossible to close the fuel cycle to achieve this one needs to abandon the
Idea of slowing down neutrons and employ fast neutrons to initiate the reaction however this is easier said than done for instance In classical reactors ordinary water is used to remove the thermal energy from the active Zone but for fast Neutron reactors water isn’t suit as it’s a good moderator so another
Liquid coolant needs to be used but what originally Mercury was considered but it quickly became apparent that this was to put it mildly not the best idea Mercury is Toxic by itself and handling radioactive Mercury is questionable moreover Mercury is chemically active forming amalgams with many metals among other
Issues a more successful idea emerged using sodium as the coolant melting at 98° C and and boiling at 883 de C in a broad range of temperatures sodium retains its properties as a coolant and Almost Doesn’t absorb or slow down neutrons however sodium has its downsides such as its tendency to react
Violently with both Air’s oxygen and water to avoid sodium’s contact with these substances complex measures are necessary for instance the reactors need to be designed not with two Loops like typical water reactors but with three Loops so passing through the reactor first transfers the heat to another
Sodium Loop and the pipes from this second Loop cool down with regular water which then Powers the turbines additionally fast reactors operate at higher temperatures imposing additional requirements on the materials used in their construction these materials must retain their structural properties better within the powerful Neutron Fields typical for fast Neutron
Reactors in extracting plutonium from spent nuclear fuel things weren’t straightforward either natural uranium and even enriched uranium fuel are relatively weakly radioactive they can be handled with minimal precautions mostly related to the chemical toxicity of uranium rather than its radioactivity however spent nuclear fuel is a different story during the fishing
Reactions it becomes enriched with highly radioactive substances its reprocessing requires technologies that exclude human presence involving lead Chambers remote manipulators and the like overall all of this is highly complex and quite costly due to the complexity and expense most countries that once experimented with fast Neutron reactors such as the USA France Germany
And Japan fairly quickly reverted to traditional slow Neutron reactors the French reactor Fenix lasted the longest finally closed in 2009 afterward for some time the Russian bn600 at the Bellar nuclear power plant remained remained the only industrial reactor operating on Fast neutrons and in 2016 it was joined by the more powerful BN
800 consequently Russia became the sole country continuing the development of closed fuel cycle technology as is often the case in science and technology persistence pays off Russian nuclear scientists perseverance produced results currently the BN 800 is the world’s first reactor that has operated for an entire year using fuel fuel obtained
Through reprocessing spent nuclear fuel however this isn’t yet a closed cycle the neutron fields in the b800 are still not strong enough for the fuel to produce an equivalent amount of plutonium during the reactor’s runtime on one fuel load in essence the BN 800 currently operates as a waste reprocessing reactor including regular
Waste from thermal reactors operating on slow neutrons this fuel comprising a mixture of oxides of very vious uranium and plutonium Isotopes is known as MOX fuel nonetheless this process is valuable allowing energy extraction from what would otherwise remain a burden in spent fuel storage additionally through this secondary reprocessing of the fuel and
Reactors many long-lived radioactive isotopes are burnt making this fuel suitable for safe disposal within a few decades this method partly addresses the second key problem in nuclear energy the issue of radioactive waste the most important part it’s almost proven that industrial reactors can be fueled with this secondary Fuel and it works
Producing a significant amount of energy so a closed fuel cycle is possible not just theoretically but practically All That Remains is to build reactors capable of producing sufficient plutonium to close the cycle this requires even more powerful Neutron fluxes implying additional Technical Solutions that need to be developed and
Implemented one of these Solutions involves olves a shift from the traditionally used uranium and plutonium oxide based fuel to nitrides which are compounds of these Metals with nitrogen indeed if the mass used in reactors uranium dioxide with the chemical formula U2 has a density of 11
G per cubic cm uranium nitride is 14.3 which is 1/3 more enabling 1/3 higher uranium nucleus density per reactor volume and consequently a denser Neutron flux similar dens increases are observed in plutonium however the seemingly straightforward operation of replacing oxide with nitride requires a fundamental overhaul of the entire fuel
Chemistry and slight modifications in reactor design however the launch of the first closed cycle reactors is planned for the near future in 2029 the simultaneous launch of two such reactors is scheduled firstly it’s the bn1 1200 reactor the older sibling of the bn600 and BN 800 reactors constructed at the
Same Bellar nuclear power plant secondly it’s the breast reactor planned to be launched at a new site in cers breast is still being considered more as an experimental project it’s a fundamentally different type of reactor distinct from the BN series reactors for example in these reactors they decided
To replace sodium as the coolant with liquid lead a significantly more inert chemical compound that doesn’t fear accidental contact with water or air another Innovative feature of the breast reactors is the concept of inherent safety according to this concept the reactor should be designed so that in case of failure of certain reactor
Systems The Chain Reaction ceases automatically and the release of radioactive materials into the environment becomes impossible in the breast reactor the active Zone containing the nuclear fuel is immersed in a kind of pool of molten lead even if the pumps that circulate the coolant shut down the circulation continues
Naturally due to convection additionally lead has the property of absorbing gamma radiation well ensuring that whatever happens inside the reactor stays inside I won’t delve too deeply into the engineering details of the breast project right now especially since there are people on YouTube who understand this better than I do and explain it
More competently in theory reactors like breast should be even safer than the familiar slow Neutron reactors while allowing operation in a closed fuel cycle generating energy while producing fuel for themselves in the future however there might be a vast array of nuances and unexpected complexities nuclear scientists still need to
Discover what these challenges might be and how to navigate them which is impossible without building an experimental reactor in essence the reactor under construction in cers will not just generate electricity although it will certainly do that but will serve as a testing ground for refining Technologies if all goes well only after
Several decades will reactors like Brest go into mass production much like what happened previously with BN series reactors now the bn1 1200 reactor yes it will operate commercially producing electricity for widespread use also based on the closed fuel cycle so yes the closed fuel cycle might become a reality by by
2029 if everything goes according to plan which isn’t always the case in nuclear energy the Practical implementation of closed fuel cycle technology will provide Humanity with numerous advantages firstly as mentioned earlier we gain the ability to involve hitherto useless uranium 238 in the nuclear cycle allowing us to increase
The resource base of nuclear energy hundreds of times over and expand our nuclear fuel reserves to last not just decades but thousands of years almost indefinitely in human terms secondly it will partially solve the issue of radioactive waste from the nuclear industry we can’t completely eliminate it but we can remove a significant
Portion of long-lived radio nuclides this enables safe disposal after a relatively short delay adhering to the principle of equivalence so that roughly speaking we bury in the earth material with the same radioactivity as the ore we extracted from the earth earlier thirdly theoretically we might be able
To do away with the costly nuclear fuel enrichment industry separating plutonium from the fuel mixture is much simpler than separating isotopes of the same element such as uranium however as I mentioned earlier such work requires adherence to heightened radiation safety measures meaning it’s not cheap in itself but according to closed cycle enthusiasts
After mastering the technology reprocessing spent fuel for new fuel could be cheaper than enrichment this comes in handy because costly in construction and operation fast Neutron reactors are more expensive than their slower counterparts meaning the energy they produce will also be more expensive if preliminary fuel enrichment savings
Can reduce the cost of this energy to Traditional Values for nuclear energy or better even lower this would be very helpful finally fourthly it would be great if the newest generations of nuclear reactors helped solve what is perhaps the most worrying problem the catastrophic consequences of potential accidents at nuclear power stations by
The way scientists and engineers in various countries are working most actively in this direction and there are already very interesting developments for instance related to creating compact low power reactors but if my dear viewers are interested we can talk about this in more detail next time
1 Comment
Amazing!