 Yes, right. Maybe I will have another 10 minutes on another topic. Somebody ask me, you stay in the room? Okay, thank you. Okay, now a more particular presentation. I will go maybe quicker through my slides, but so about coolant, coolant control and purification. So why it's necessary to purify the answer is here. There are too many reasons to purify, several reasons to maintain the quality of the sodium. I've used some idea about that for the primary, for example, for the primary coolant answer. So we have the, for the primary oxygen is a key parameter for any corrosion phenomena, but we don't have like for lead some kind of ranch of oxygen content. The lowest is the best we consider generally and we need for reasons to, if you have corrosion in the structural, in the structure of the fuel assemblies in the hot part, you have, you have of course corrosion and you have production of activated corrosion products, then you will have, you create contamination. We have manganese 54, cobalt 60 and so on. And so these products can be transported by mass transfer from the hot part, the core, to some other parts of the reactor. So it's important to, to limit that because you have a, if you have some dosimetry on the components, when you want to repair, you have a necessity to decontaminate clean up. There is your sodium with the steam, as I told you previously, and we have also to apply a so-called decontamination process, okay, using acidic bath generally. You have some acids that are able to extract the first, the deposition and the first nanometers in order to reduce the dosimetry. I, maybe I will give you some information tomorrow. So, necessity to master oxygen. Master, to master oxygen, what does it mean? It means that we need to maintain oxygen level, generally it's considered below 3 ppm. 3 ppm, it's easy to obtain. It is generally obtained on the reactors in operation we had and also currently used at the moment. Oxygen, but oxygen can induce a precipitation of coolant oxide, not in the case of sodium, generally because the sodium oxide, the oxygen is dissolved, but for lead, for example, we have precipitation, we can have precipitation of lead oxide. Okay, I tell you that previously, it is the same case for lead business. For intermediate circuits, so it's clear that it is a case for sodium, fast reactor. What I told you that to detect a sodium water reaction, we need to detect very quickly the injection of water. So what we measure is the hydrogen. I told you that there are different systems to measure the oxygen, the hydrogen, sorry. So, but if you want to detect a very small variation of the hydrogen content, it's necessary that in normal operation, you have a very low, very low value in steady state operation. What we have is that in normal operation on the water side, we have corrosion of the steel on the water side which produce hydrogen. And so we have a continuous source of hydrogen in the steam generator and this hydrogen, due to the difference of partial pressure, move through the wall from the water side to the sodium side by difference of partial pressure. And because hydrogen, you know, is able to permeate through the walls. So for this reason, it's necessary to purify the secondary sodium, mostly with regards hydrogen. Primary circuit is for oxygen, mostly, with regards corrosion. And for the secondary circuit, the main reason is generally to maintain hydrogen as low as achievable. Yeah. Of course, we need also in case of any ingress of pollution also to maintain a low concentration because there is a risk of precipitation, crystallization of impurities, sodium oxide and sodium hydride in some narrow gaps. In this case, you can have a perturbation of the circulation of the fluids. This can be typically the case in the secondary loop in case of sodium water interaction, which is not or in case of repair. If you open the circuits, you introduce air, you can have oxide and then you have a pollution of the sodium. So it's necessary to reduce this pollution. And for, okay, for SFR, okay, you remember this circuit and then go come back again. So the main, we have a continuous sources of impollution, diffusion of hydrogen through the steam generator walls, impurities in the cover gas also, necessary to have to master the quality. Because if not, the sodium is really likes to attract oxygen, of course, okay, due to his chemical characteristics. We have some discontinuous pollution. When you introduce some oxides in the sodium, some metallic elements in the sodium, you know that on any metallic elements, you have some oxides on the surface. But when you insert this, for example, fuel assemblies in the sodium, the surface, you have some oxides that are reduced by the sodium, because sodium is a reducer, okay. So you have a pollution of sodium by this oxygen. Just to give you an information for superphoenix, the surface in contact with sodium was about 48,000 square meters, okay. It's a reservoir important. So even if the pollution is limited for a square meter, multiplied by the surface, you have a significant quantities of pollution. Okay, this is the same for all the reactors. This is the reason why at the very beginning of the operation of the reactor, we proceed generally by introducing inlet gas, nitrogen, for example, heating up to 200 degrees Celsius, drying the surface, and so on. So you have some kind of outgassing of the structural material, and then you start to introduce your sodium. It's just to limit the amount of pollution you could get in the sodium. But fortunately, we have a process to eliminate the pollution. We are going to intern this field. Air ingress after repair, this is very important. Water ingress in the steam generator unit, you discuss that. Sometimes all ingress, okay, from the pumps, for example, if you have lubricating material in the pumps, you have to check that there were some events where you have the release of oil in sodium, like in Phoenix, in PFR also, and maybe some other reactors. Small amounts, but you have production of carbonaceous products. Sometimes metallic feeling due to the amount of some small particles of metals. This was the case for Kain-Katu reactor in Germany, and some other cases also. Okay, so here you have exactly the detail of what I have said. Here you introduce the metallic surface in the sodium. You have oxide decomposition, transfer of oxygen hydrogen in the sodium, and then you increase the concentration. So, generally, SFF must be operated with oxygen content below 3 ppm in normal operation in order to control the generalized corrosion. But generally, this approach is successful for sodium-fast reactors. Okay, here you have the contamination source. Here you have activated corrosion products, as I told you, coming from the core, the structural material. You can have sometimes some fuel and fission products in case of cladding rupture, okay, the clad rupture. You can release some fission gas, and sometimes some particles. It can happen. And tritium. Tritium is coming from the two sources of tritium, ternary fission of plutonium, and the second production is from the boron carbide, the boron produced on tritium also. So, when you have tritium produced in the primary circuit, tritium is hydrogen. You know that tritium, when you have walls at high temperature, is able to diffuse, to permeate in the secondary loop and then on the water side and so on. So, it's important to master also the hydrogen, the tritium in the tritium and in the reactor in order to avoid to reach the limits acceptable for the, for the, in order to satisfy the regulation. For secondary, yes, you have here a system, it's to illustrate the secondary. Here you have the wall, hydrogen is coming, here you have the steam generator, secondary circuit and primary circuit here. Here you have the corrosion, the corrosion on the water side, diffusion of hydrogen, okay, in a steady state situation, and in some case injection of sodium water here with production of hydrogen, necessity to maintain the hydrogen as low as achievable. Okay, one characteristic, yes, of sodium, it's very important, it seems not oxygen and hydrogen, which has the two key impurities in the, in the sodium, oxygen coming from the air and oxygen and hydrogen coming from the moisture, from the humidity. What the key characteristic is that you can notice that when we are near the melting point here, the solubility, the solubility of oxygen and hydrogen is very, very low, okay. So, it is an important thing and we have of course an increase of the solubility as a function of the temperature, but this characteristic is very interesting, it's not the same for example for lithium, which is a product which is close to the sodium, but with regards the chemical solubilities, it's not really the case. Okay, so there are different techniques for the sodium purification. Okay, first specific method to obtain nuclear grade sodium, when we buy sodium, we send some requirements, a list of values to be satisfied by the producer, of course. Initial cleaning of loop, what I told you, okay, injection of inert gas. Filtering can be useful particularly at the beginning in order to eliminate the residual particulates you have in the sodium. In normal operation, in normal operation, in a fast reactor, we don't need filter, okay. This is very important. We have no specification on a filter and what we observe are all the reactors in operation. We didn't face any problem due to the circulation of particulates. Cold trapping, I will explain more detail. Hot trapping, hot trapping is when you introduce an element, a material which is a getter. I mean, if you have oxygen in the sodium, you introduce, for example, zirconium, zirconium titanium, and you produce zirconium titanium oxide which eliminates the oxygen which is dissolved in the sodium because zirconium titanium is a more efficient reducer than sodium itself. And of course, a lot, the most important maybe is when you are doing some maintenance operation, is to control the ingress of various pollutions. Crystallization method, different method. Liquid evaporation, you know that, okay. When you want to produce a salt, okay, you are waiting for the sun and the evaporation of the water and the end, you find some salt. With sodium, it's difficult to imagine such a process, okay. Second one is the reduction of the solidity by adding some additive impurity. Difficult also to imagine that you want to inject an additional product in a nuclear system. And last one is cooling the liquid below the separation temperature. So this one is the most attractive and we are going to discuss this point. So now we are going to explain. We are in Italy, so I'm going to speak about coffee, okay. We changed just from sodium to coffee. When you have a coffee, generally you like to add some sugar, okay, doppio espresso, okay. And you add some a piece of sugar so you increase the concentration. You reach this value, yeah. If you like more sugar, okay, two pieces of sugar. It starts to be, can be dangerous, but, and you increase the concentration. In fact, you are near the solubility temperature. If you add again a piece of sugar, what happens? At the end, no dissolution because in fact, you reach the saturation and then you have, of course, your piece of sugar is destroyed, but you have the crystals of sugar in the bottom of your cup. But, okay, this is, so assuming that you are, let's say, reasonable, okay, you take care about your sleep, you are sleep, so you have to take care. And so you instead to drink your coffee, sometimes you need to discuss with colleagues and so on, blah, blah, blah. And what happens? The coffee, the coffee, the temperature reduces, okay. You reach this concentration, but instead to drink your coffee, temperature of the coffee decreases, yeah. In fact, you go through a solubility curve. Generally, nothing happens. You need to reach, we have a so-called metastable region, you reach, you need to reach a solubility curve, which is a physical property. And in the case, at the end, you reach this value. What happens? If you look the coffee, same color, nothing happens. If you taste, of course, it's colder, coffee is colder. What you observe, you observe a crystallization of sugar at the bottom. It's not pieces of sugar. It's really, it sticks to the bottom. You need to put some to throw out the coffee and to clean up with hot water, okay. So it means you have a crystallization at the bottom. So what happens? In fact, you cool down the coffee and you have the sugar at the bottom, yes? So it means that if you want to eliminate the sugar from the coffee, this is a stupid idea, but it's easy. It's easy. You cool down your coffee, okay. Pour your coffee in another cup, heat up again, and you will have less sugar, okay. But for sodium, it's exactly the same. I don't recommend to drink sodium. Okay, two phenomena, nucleation phenomena. You produce small crystals, small crystals, and we have a so-called two phenomena, nucleation and growth. It's important, theoretical part, but you have nucleation production of small crystals, I would say babies, okay, and then these babies are growing. So we can have homogeneous or heterogeneous nucleation. Homogeneous is in the sodium bulk. Heterogeneous, you need some surface, metallic surface to create the sites to promote the nucleation. In sodium, we have generally heterogeneous nucleation. You need surfaces. You are not in the conditions to have homogeneous nucleation and so production of particulates. You don't have sodium oxide particulates. About growth, the phenomena of growth, maybe you have noticed when you are looking at the salt you have on the table, but crystals produce naturally like here. You can notice the shape, specific shape, pyramidal shape here. We have exactly the same with the sodium oxide, okay, exactly the same shape for the crystals, pyramidal shape. And if you have a low super saturation, it means low distance between the solubility and the temperature. If you are near the solubility curve, you have a pyramidal growth. If we are far, you have dendritic growth, okay. Some phenomena, kinetics are different mechanism, but nevertheless, it's same. You have here, when you have for growth, we consider here you have the crystal, here you have a boundary layer, you have a concentration and here we assume that we have two steps, two steps in the crystallization, diffusion through the boundary layer and then integration in the crystal lattice, yes. So the kinetics of the overall phenomena is the kinetics of the slowest step. It's like when you are in Autostrada or Tobal, if you have the velocity of the car, the velocity of the duration of your travel depends of the slowest car, okay, traffic jam. So we did studies to study the kinetics. This is the kinetics where you have a renews type low, where you have a constant activation energy, reference surface, super saturation means the difference between the concentration and the solubility at the same temperature and the same low for growth and for nucleation. We have measured these parameters and particularly the activation energy and order of the kinetic. What we have observed, we have measured the two kinetics for sodium oxide and sodium hydride and we have observed that for hydride, we have a very high order, so it means that it's very sensitive to the difference of temperature. As a consequence, we can have crystallization of hydride just only on a cold wall. And for the growth, we have what was observed also the kinetic of the growth. We have a growth limited by order of one and it's here, order of two for hydride. What does it mean? If you have a theoretical approach, I don't go in detail, but it means that for oxide, the limiting step is the diffusion of oxygen through the boundary layer and for the hydrogen, the limiting step of the crystallization is the integration in the crystal lattice. The main reason is the size of the atom. For that, the diffusion has some link, the diffusion rate, diffusivity has a link with the size of the atomic of the atom. So we have established these kinetics and what we have observed is that, for example, we have developed a cold trap where here you have a cooling area, a wall, and we are able to have a sodium hydride deposit and here sodium oxide deposits. For oxide, we need more time, okay, more time for the crystallization. This is the reason why we separate the impurities. We have developed a concept called PsyCos where we are able to separate hydrogen and oxygen. It has some importance for operation. For example, for a secondary trap, in normal operation, you have hydrogen diffusion coming from steam generators. You have deposition here, but in case of sodium water interaction, you still have some capacity for hydride and the lower part can be used for the oxygen which is introduced due to the introduction of water, okay? So it means that this kind of approach is quite interesting and we developed this kind of concept. To model, I give you about simulation of this system, you can notice that in such a system it's not like another component. Another component is the same from the beginning to the end, but here you are accumulating impurities. So it means that the circulation of the sodium inside, you increase the pressure drop, of course, because you are accumulating impurities inside. So it means that you have a system where you need to introduce crystallization kinetics. You have also cooling thermal transfer through the walls, okay, to simulate, and you have also hydrodynamics, and particularly hydrodynamics, sorry, in this area, yes, you can have a recirculation because here you have a cold wall, okay, and you have some recirculation. The cold part is again close to the wall, and the lower part is isothermal, but with a pressure drop. So it's rather complex because you have to model here, and you have to take into account the fact that you have also evolution of the geometry inside. Because if you have deposition on the wall, you have a progression of the of the surface, exchange surface. So we developed a model with Comsol Multiphysics, somebody yesterday we discussed that in front of a poster with Comsol, and we had, it's okay, what we model is the behavior of two different impurities with a specific kinetics, and we are using this model to simulate the evolution of the deposition and the feeling rate of the cold trap with time. So it's very important to predict the loading of the cold trap, sometimes to predict the change of the cartridge, sometimes. So it's very important to develop such a model. So we developed this model, let's say recently, and now it's easy to simulate the culture. I don't go in detail, but what you can see, for example, for oxygen, we are simulating the evolution of the accumulation of impurities in the cold trap, okay, when you have a mesh, for example, here. Another case is here, when you have deposition in this part, the cold wall with deposition of hydride. Here you have the results of a mock-up. We did experiments with single impurity, hydrogen or oxygen in order to study the various phenomena, and here you have the liquid, the crystals, and what we call, we have a so-called diffusion interface where we have diffusion of impurities in this porous media, okay, and we have mass transfer and growth of the crystals which are on the wall, okay. So here's the model, it's a rather complex model, but you have a diffuse interface and so on. And so we are modeling this basic phenomena inside, but what we need also is to couple with CFD simulation in the middle of the cold trap because you have some recirculation phenomena. For that, we use in the upper part, Fluent. We connect Fluent and Consolumenti Physics, okay. Here you have some kind of evolution of the deposition with time and so on. So we have made a validation of this data with using some experimental studies we did several years ago. Okay, the methodology for designing a purification system. In the past, what has to be done? Identification of the impurities to be removed, so you need to estimate the pollutions, of course. Assessment of their source and their production rates. So we have a lot of experiments and also feedback from the operation of reactors. Assessment of potential things. For a primary circuit, if you want to purify oxygen, you are in competition with the corrosion phenomena. A corrosion phenomena is a consumption of oxygen also, okay. So you need to be more efficient, I would say, than the corrosion. Yes, in order to limit the corrosion. If not, it's not necessary. And so here you have some specification on the removal rate, okay. And you have to take different scenarios. About the, you have an evaluation of the amount of impurities to be removed from the sodium circuits. So you induce some specification on the loading capacity. Previously on the removal rate. And now on the loading capacity of the cold trap. It depends on the amount of impurities. And you have a selection of several trapping zones. It depends on what you want to do if it is specific for hydrogen, for oxygen, for sodium hydroxide, and so on and so on. So you need to have some kind of operational feedback, some ideas about the geometry. Okay. Here you have the main parameters for these main design criteria. Efficiency, which is difference of the variation of concentration you have compared to the maximum variation you can have. It means the difference between the concentration and the solubility. Normally you can't go below the solubility because after that you have no more potential for the crystallization. You have the purification rate, efficiency multiplied by the flow rate and by the difference of concentration, and so on. Capacity of, also capacity of the cold trap, maximum amount of impurities you can load. So it means you have also an idea about the duration, life duration of the cold trap, or when you will have to change the cartridge, which is filled with impurities. And compactness also. You can have, if you have a cold trap with an area like that to trap the impurities, but a component which is 10 meters high and 2 meters of diameter, it's not very efficient system. Okay. You agree with that? So some decisions about short life, and you have a discussion about the capacity, about the service life, short, long, and so on. In Super Phoenix, we have a very interesting system which has been developed. It's integrated purification system here, where you have the, each component has its own electromagnetic pump, heat exchanger to lower the temperature for 550 to 110. Okay. You have intermediate exchanger. The cartridge is in the middle here. You have a coil here to cool down with nitrogen. Nitrogen was used to cool down the temperature. You can imagine, here you have a 550, and here we have a 110. And the diameter is 1 meter, 1.2 meters. Okay. So it means that we have also insulation inside. And in the middle, we have a cartridge. Okay. The cartridge is introduced here. Okay. And when the cartridge is full of impurities, you extract only the cartridge, and you put a new cartridge inside the coal trap. In this system, we avoid to change all the components. This system is an option of reference, for example, for BN 1200 reactor in Russia. Okay. Qualification in the 80s, definition of the main requirements, design of the scale one coal trap of the reactor, identification of some similitude rules, and downscaling of the mockup, fabrication of the mockup, testing the mockup, and so on. Today, we use the new code I described to you. Okay. We don't need to perform long experimental studies. Now, we consider we have enough data for that. To control the impurity, also we have oxygen meters, hydrogen meters, but we have also another system based on the deposition in the narrow gaps. Deposition in the narrow gaps here. We call down the sodium, and we saw at the coldest point here, the sodium goes through very small holes. When you are at the right temperature, you create the good conditions to have some crystals. And so you observe a reduction of flow rate, of course. So it gives you a good indication of what is the temperature at which you start to have impurity, presence of solid impurities. And so it gives you an idea of the concentration of oxygen and hydrogen you have in the reactor. Another option is to, as I told you, hydrogen meters here. You have a nickel membrane. Sodium circulates inside the red pipes. On the other side, you have a vacuum, secondary vacuum. So you promote the diffusion of hydrogen from the sodium to the vacuum, and then you have a mass spectrometer. Second system is an electrochemical hydrogen meter developed, for example, by E.G. Carr. Or lead, the first reactor. Okay. The situation is different. Here you can see this area, as it was said yesterday. You have the fuel elements with upper part. They are fixed in the upper part. Why? Because of the BNC. And so we have steam generators directly in the, I would say, in contact with the primary coolant. Here you have a challenge to maintain the oxygen, normally between these two values, curves. Here you have a precipitation of lead oxide, and below you have dissolution. Dissolution of some oxide on the surface, and you lose the protection of the surface, except if you have improved coatings and so on. So there were some, a lot of studies on the mechanism of corrosion and the behavior here. I don't come back on this point. But about purification, we had a discussion about within the frame of a European project called leader. And we discussed that you have to take into account several parameters. Of course, the minimum, you have to work between 400 and 480 degrees. And so you have, so in this case, some specifications about the oxygen content with some safety margin in order to avoid to be too close to the minimum oxygen content below which you risk to have liquid metal and right amount. Okay? So, and of course, this is possible to reduce this value because to decrease depends on coating properties. So there are some, we're taking into account some margins. Here this is the same diagram I have tried to do with lead instead of sodium. Even case of, if you have lead oxide, you have probably some lead oxide on the surface, which is more, you need to have additional process, chemical process to reduce this lead oxide. If you have a steam generator, there will have also hydrogen production and trisium probably somewhere. Okay? Because maybe they use boron carbide and they will have fuel. So, trisium has to be analyzed more carefully for heavy liquid metals systems. Consequently, one potential events, what we need here is that detection in cover gas, if water ingress, very small amount of PBO produced continuously, detection by oxygen meters. This is the reason why they develop also oxygen meters for lead, different oxygen meters, but different technology, but same principle. In fact, electrochemical oxygen meters and there's probably also to have hydrogen meter in the gas plenum or water in order to monitor the hydrogen content for the chemical control of the lead. Then in both case purification by filtration. Filtration is with heavy liquid metals, mandatory, but also hydrogen reduction. Sometimes we can envisage also in some case what we call over-floating and collation in dedicate vessel for sodium fast reactor. We develop this system when you have a pollution at low temperature on the surface, we have the possibility by over-floating to transfer the impurities in a dedicated storage tank. Oxygen control in a hot and cold plenum in a lead fast reactor. What is important is we have requirements for oxygen content. It is important also to take into account the consumption of oxygen by corrosion in the steam generator and also in the core. We have defined two parameters, RC1 and RC2, rate of oxygen consumption in the core. In fact, you need to have system modeling, the evolution of the oxygen content in the reactor. So it means that we have to have a system here to add oxygen for example with PBO pellets or with how to reduce oxygen by injection of hydrogen. It is of course a system which is theoretical but this is the main basic principle. Okay, I go through. There is also a system to control the oxygen. There was a system which was developed by Russian colleagues from IPP. So it's a system which allows to dissolve oxygen. We test also that, for example, in France, in Kedahash, not the same exactly but the same principle. What we suggest also during this project is to have maybe why not to have a filtration integrated unit here. Maybe it's not a reference for the Alfred project at the moment. We have no more contacts on this item but it means that in principle it could be possible instead to have an integrated option with an electromagnetic pump and a filter in order to purify continuously the lead. Okay, here you have the systems for lead filtration. Several options were the test, porall, dinalloy, park cartridge. There was a lot of studies performed during previous European projects in order to study the performance of various filters media. And here you have the conditions, temperature, flow velocity and so on. In LBE, in LBE, this is the landscape. It's a courtesy of S.E.K., Mr. Gladinek, who is a PhD student working on the purification systems in Moor and the University of Ghent. And he did seminar studies we did for the sodium 40 years ago. And he studied also the behavior of oxygen in lead. And we have results similar properties. We have solubility laws, sursolubility in order to promote the crystallization of lead oxide or impurities in a inocule trap. Okay. He has to face about the same same pollutions, okay, in the lead. Because we have, even if the coolant is not the same, we have similar operational constraints, I would say. Necessity to have a tightness and so on. Solid particle formation in LBE. Okay. So what is important is also here you have an estimation of the total amount of corrosion products. If you, during the operation of Project Lymeera, here you have the total amount of corrosion product you could accumulate during 40 years. So it means that it's very mandatory to control the oxygen content. So there were some studies using facility in Moor. Okay. You have a comparison of the kinetics observation that was done in generally you have the information on lead and between brackets you have the situation with sodium, comparative situation. So there was here a modeling, not you don't separate here oxygen and erosion. We have a general Moor general approach with the adimensional numbers with the Sherwood as a function on the Reynolds and Schmidt adimensional numbers. So these correlations and you need to estimate of course the orders of the kinetics. So all these kinetics were done in SCK in Mexico loop. You have the reference here of Mr. Chris Rossell and colleagues from SCK Moor. What we did also sensors, oxygen meters, I don't go in detail but in lead business also there was a good development of instrumentation. Yesterday we have seen some information also on oxygen meter. Trisium and hydrogen I think they have to, I don't go in detail but the same problematic than with sodium. Some words about GFR. Here it's generally you have also to maintain oxygen content also and what we need is to control the oxidizing potential in the coolant in order to have a, to protect the metallic materials against corrosion. So there are some, you have to limit the oxidation of carbon-based material. So we have by water injection and control of hydrogen to hydrogen ratio. So we did some studies in Katarash. We have here is the same information differently presented than for sodium and lead but you have the various sources of impurities. Okay for some of them is the same, efficient and activation products, particles, okay particles are a specific problem with the gas. About the background of anelium purification, there is some, there was some studies. The purification system principles are filtration, oxidation of hydrogen into water of oxygen into water, adsorption of impurities on some fixed beds. So you produce some water and so after that you have some molecular sieves, okay. Here you have the some specific possible recommendations for VHTR for example to be updated for GFR. I don't know what is the situation now but you have the, for various impurities some, some specifications about the partial pressure, okay, about these impurities. These values in order to maintain a good behavior of materials in a gas system. Okay so here you have a reference process for helium purification, first filtration, it's real particles, then oxidation, then adsorption of the trapping of water but also CO2, methane and NOx, adsorption, adsorption of some activated carbon, okay, in under cryogenic conditions for nitrogen, oxygen and some residual species and so on. So this system was studied, currently it's also studied for ESS project, European Spalation Source, which is currently implemented in the University of Lund in Sweden, okay, so there are some studies related to the purification of helium in another field, okay. Okay, alternative purification system, membrane, gaiters, helium cryogenic traps, I would say that some of them have been studied also for fusion in the frame of fusion, particularly the membranes and gaiters also, because we have some helium circuits in the, in the, in the blanket, blanket of ether for example and so on. So what we almost finished, we did some experimental studies to study the kinetics in Kadarache, we have some facilities, sorry, yes, Signe facility, these facilities dedicate to study the systems to control the helium characteristics and to study the performance of various systems to convert for example the, the hydrogen into, into water, the trapping, the molecular sieves and so on. Another facility called HPC, a large facility which was developed in support to the gas fast reactor called HPC where we have the specification of the process, oxidation to produce, okay, to produce water, molecular sieves, activated carbons and so on. So I have given shortly information on gas but you can see that on all these coolants we need to control the impurities and particularly oxygen of course but not only and particularly for gas. So I would say that for sodium is maybe the easiest case because we take care about oxygen, hydrogen and solubility are very comfortable for that and cold trapping is efficient. For lead is more tricky because maybe we have to deal with particulates and filtering operations and also a chemical control of oxygen and for gas also of course it's more related to the mechanical, the material behavior and we have also the feedback what I didn't mention is that we have some feedback coming from the British reactors, we had some good exchange to go fast project with UKEA ten years, eight years ago in this field. Thank you very much for your attention.