Method and plant for recycling of spent nuclear fuel

FIELD: fuel systems.

SUBSTANCE: invention is related to recycling of return nuclear fuel (RNF) and materials of blanket region (BR) of fast breeder reactors (FBR) for their multiple use with the possibility to adjust content in creation of a new fuel composition. Initial chemical state of processed material may vary: oxides, nitrides, metals and alloys. Method represents a combination of serial processes of chemical transformation of radiated nuclear fuel (RNF): fluoridation with gaseous fluorine and extraction of main uranium mass; transition of fluoridation remains into oxides (pyrohydrolysis); - chlorination of oxides in recovery conditions with group separation of plutonium chlorides, uranium (left in process of fluoridation) and fission products. Further "plutonium" and "uranium" fraction, and also fraction containing fission products (and, possibly, minor-actinides), are used each separately in various processes according to available methods. Earlier produced uranium hexafluoride, with low boiling fluorides of fission products, is cleaned from the latter and used, according to objectives of processing, also by available methods. Using waterless processes with application of salt melts, suggested version makes it possible to realise continuous highly efficient processes of fuel components production, moreover, it is stipulated to carry out preparation stages in continuous mode. Plant for processing of spent nuclear fuel containing uranium and plutonium includes three serially installed devices: fluoridiser; pyrohydrolysis device; chlorinator-condensator-granulator device. Two last devices are of flame type. The last of devices represents a pipe with a central element, in which lines of inlet product and reagents supply are installed. In lower part there is an expansion in the form of pear with a flame burner along its axis, and medium part has a row of conical shelves inside, between which there are nozzles with pipelines for chlorides outlet. Nozzle for chlorides outlet is also arranged in lower point of pear-like part. Nozzle for exhaust of non-condensed gases is provided in upper part. Granulator is arranged as reservoir with low boiling incombustible liquid, and to produce drops, capillaries are provided at pipeline ends.

EFFECT: highly efficient method for processing of spent nuclear fuel of practically any composition from thermal reactors and fast breeder reactors, blanket region of fast breeder reactors and some other types of reactors with the possibility to produce several other types of fuel compositions.

19 cl, 3 dwg

 

The invention relates to the field of nuclear energy, in particular to recovery (recycling) recycling of nuclear fuel (SNF) and materials area of reproduction (3V) fast reactors (RBN) for their repeated use and adjustment of the composition during the formation of the new fuel composition. The original chemical state of recyclable materials may be different: oxides, nitrides, metals and alloys.

Classic (water) is a method of processing spent fuel [Chemical technology of irradiated nuclear fuel. Edited Via. - M, Atomizdat, 1971] widely known and along with the merits has two major drawbacks:

- large volume of liquid waste (high costs of translating them into less dangerous condition);

- low radiation resistance of the used aqueous and organic media (the inability to work with malekmadani SNF, additional fire and explosion hazards).

Known forinnovative a method of processing spent fuel [Jonke A.A. Reprocessing of nuclear Reactor Fuels by Processes, based on Volatilization, fractional Distillation and selective Adsorption. Atomic Energy Review, V.3, No. 1, 1965], which consists in the fluoridation of the crushed oxide SNF, the transfer of the entire amount of U and Pu in conjunction with many elements, fission products (AP) volatile low-boiling fluorides (NCF). Then U and Pu released from these NCF (hold them clear is). Hereinafter, jointly or separately treated hexafloride U and Pu can be used in different scenarios:

- re-enrichment in the isotope235U;

separate processing in the dioxides (including method of pyrohydrolysis);

- joint conversion into fuel (MOX, including method of pyrohydrolysis).

The method is characterized by high performance head on stage (fluoridation, the separation of uranium and other NCF from non-volatile high-boiling "leftovers" fluoridation - (WCOF)), without intermediate transformations to perform correction of isotopic composition of uranium and subsequent transfer of uranium hexafluoride method pyrohydrolysis into carbon dioxide, suitable for the production of fuel elements as technology of vibrocompaction (granulation)and "tablet" technology ("Pesenka").

The disadvantages of the discussed method is:

1) thermal and radiative instability of plutonium hexafluoride, which lead to the formation of deposits of solid PuF4in the used equipment and pipelines, which makes their maintenance, reduces productivity and increases radiation hazard;

2) thermodynamic properties of fluorides of uranium and plutonium are such that the equilibrium PuF6+UF4→PuF4+UF6strongly shifted to the right, i.e. only after a full translation of uranium in the gas phase is possible eriod in the gas phase plutonium moreover, for the complete conversion of plutonium hexafluoride requires a considerable excess of fluoride.

Can be implemented variant, in which the plutonium is not foryouth up hexafluoride, leaving him in the amount of VCOP in the form of a PuF4it doesn't translate into the gas phase as a certain amount of uranium (percent). Then, uranium hexafluoride, proceed as in the previous example-analog and VKOF transferred to the molten salt, then Pu can be purified from PD pyrochemical method and extracted in the form of PuO2[Vphurynv and other "radiochemistry"Journal, Vol.18, issue 1, pp.109-114, 1976] or other known methods.

The disadvantage of this method is the low performance of the extraction and purification of Pu, the impossibility of direct use dedicated PuO2in the technology of concrete vibration, as well as the limitations of the translated versions in other fuel composition, in addition to oxide: metal (alloy), nitride (rigidity technology).

There is a method of processing spent fuel using molten alkali metal chlorides [A.V.Bychkov, S.K.Vavilov, O.V.Skiba, P.T.Porodnov et al. Pyroelectrochemical Reprocessing of Irradiated FBR MOX Fuel. III. Experiment on High Burn-Up Fuel of the BOR-60 Reaktor. Proc. Int. Confer, on Fut. Nucl. Syst. GLOBAL'97. Oct.5-10, 1997, Yokohama, Japan], including the dissolution of powdered oxide SNF by bubbling gaseous chlorine. Then hold:

separating the electrolysis emitting at which atode some fraction of U in UO 2with partial (or full) inclusion electrophoretically PD: Zr, Nb, Mo, TC, Ru, Rh, Pd, Ag;

oxidation of the melt and subsequent volumetric crystallization PuO2;

- electrolysis to extract U (UO2) with PD (part REE) and components construction materials (CCM);

- regeneration of the melt to re-use (using phosphate), in the melt remain DD: Sr, BA, Cs.

The disadvantages of the discussed method are:

- translation of U in substandard condition (which is unacceptable for spent nuclear fuel from power reactors on thermal neutrons (PTH) and SV RBN);

- low productivity due to the periodicity of the process, the operation of which (in several stages) is carried out in one apparatus, tub which has a short service life;

- lack of other options selection Pu, except bulk crystallization PuO2(rigidities technology).

From the available sources it is known that when chlorination (high temperature, the presence of a reductant) any oxides and mixtures of oxides can be converted to chlorides [brief chemical encyclopedia / edited Elecronica, Gayhardcore, Aiyaa and other M: Soviet encyclopedia, 1963]. It is known that the resulting chlorides have substantially different boiling point (condensation) in the range of more than 1,500 degrees [Koronovskii IT, Nazarenko, Y.P., Not the hot E.F. Quick reference for chemistry. Kiev: Academy of Sciences of USSR, 1967. P.40]. You can imagine the process by which oxides (SNF) glorious, a pair of chlorides sent to extended capacitor in which at least reduce the temperature deposited more low-boiling chlorides. However, the technical solution with high performance to carry out the chlorination of oxides and continuously output from the condenser split (fully or partially) chlorides, could not be found.

The technical result of the invention (purpose) is to develop a high-performance method of SNF processing of almost any composition (oxides, nitrides, metal alloys) of PTH, RBN, zones reproduction RBN and some other types of reactors with the possibility of producing several types of fuel compounds (oxides, nitrides, including U-Pu fuel on the basis of mechanical mixtures, metals and alloys).

The invention consists in that at the initial stage of processing of the crushed fuel foryouth, with U partially left in VKOF, in this case, thermodynamic properties of Pu remains in the "fixed" state. The bulk of U in the form of hexafluoride and all NCF PD sent for "uranium" redistribution, where they cleaned hexafluoride by known methods, if necessary, correction of isotopic composition is depending on the task to produce fuel composition (oxide, nitride, metal, alloys) by known methods, preferably in continuous mode).

VKOF, including fluorides Pu, MA and PD transfer (pneumatic or "gravity") pyrohydrolysis (fiery apparatus) for the conversion again in the oxides on the generalized reaction

where n is the coefficient to determine the stoichiometry;

Q1- thermal effect of reaction, kJ/mol.

Because of heat Q1for reaction may be sufficient, provided to receive additional heat from the reaction

where Q2- thermal effect of reaction, kJ/mol.

The contribution of reaction (2) (up to 100%) is determined depending on the performance and regulate the flow of reagents. Combustion reaction of hydrogen and oxygen by itself is easily controllable and can serve as a "duty"maintaining the device in "standby mode"when there is no supply of the input product and the reactants.

Excess reactants and gaseous reaction products are not waste, because they can be separated by known methods and used again. Hydrogen fluoride, oxygen and hydrogen can easily be divided stepwise cooling and return to the cycle [e.g., see Pat of the Russian Federation. The method of purification of chlorine-containing gases from radioactive aerosol particles actinoid / Rchases, Lgeil is, Atherodes etc. // BI, 1992. No. 8; Pet of the Russian Federation. The method of condensation of chlorine from waste gases and a device for its implementation / Rchases, Lgobal, Athiradi etc. // BI, 1997. No. 2].

Oxides send (pneumatically or by gravity) on the stage of chlorination (replacement fiery apparatus) according to the generalized reaction

where n and m are the coefficients to determine the stoichiometry;

Q3- thermal effect of reaction, kJ/mol.

Allocated by the reaction heat Q3may not be enough to increase the heat you should use reaction

where Q4- thermal effect of reaction, kJ/mol.

Because the input of the oxide product will be UO2when it chlorination in the presence of Cl2except UCl4can be formed UCl5and UCl6.

For the regulation of the redox environment in the reaction zone, you can use the options:

increase the share of H2in reaction (4);

- additive UCl3U(meth)or UH3(in fine condition);

- additive Na vapor state.

Supplements (except UCl3also making their thermal effect QEXT.

On the contrary, to increase oxidative capacity of the environment can be increased additive Cl2(mind nishat share of H 2in reaction (4)).

As the burning of hydrogen in oxygen, reaction (4) is easily controllable and can also serve as a "duty"maintaining the device in "standby mode"when there is no supply of the input product and the reactants.

When some tasks stage chlorination condensation may play the role of the parent, i.e. at the stage of chlorination can do the initial oxide SNF (after grinding: chemical for SNF PTH, as well as uranium spent fuel and material SV RBN; mechanical - mixed SNF RBN), then the "role" of the uranium component and the low-boiling chlorides (NCH) DD will dominate.

High-boiling chlorides (WSU) PD and components construction materials (CCM) (even taking into account their joint fusion) at the operating temperature of reaction (3) may remain in the solid state. For their transfer to the liquid state (for output from the reaction zone) provides either the above-mentioned additive Na, which is translated in NaCl or directly additive NaCl in the reaction zone. The options are:

- submission in fine condition with oxides or with gaseous reagents that may be useful to regulate the reaction rate;

- flow in granular or molten state in the condensation zone WSU PD and PFC.

Gaseous reaction products and excess reagents (HCl, H2O, Cl2N 2) are the condensation zone, then they are sent for purification from radioactive aerosols and other impurities by known methods and used again after separation or discharge, if it is cheaper.

Chlorides U (UCl4), Pu (PuCl3), minor actinides (MA)PD, CMC (and additive NaCl) will condense in the reaction zone and around it at the temperature that corresponds to their properties at the selected operating pressure. Depending on your technological problems of condensation of chloride can be conducted on two (separation only U and Pu) or several (three to any reasonable n: separation of U, Pu, MA; group and individual securities division of DD) sites.

Two variants are possible condensation:

in the liquid state (including by fusing a mixture of chlorides, close to the boiling point or sublimation); in this case, the withdrawal of the product from the condensation zone (including each plot) can be arranged in a continuous mode. In addition, when the partial flow of the liquid condensate from the overlying sections on the downstream can be realized the approaching rectification, i.e. with a more "strict" separation of chlorides on sites;

in solid (or, mainly, in the solid state), then for each site shall be provided periodic heating to complete the fusing of chlorides on the surface condensation or introduction to relevant areas of low-melting salts and their joint conclusion from the condensation zone.

After withdrawal of the product from the condensation zone (in liquid form) they should make it more convenient for transportation (when loaded into the apparatus), and for temporary storage. For this purpose, liquid salt Plav transferred to drops and record the condition of the solidification (granulation) in boiling non-flammable liquids (e.g., CC14) or by other known methods.

WSU PD and ECR with the addition of NaCl (or without, if the working temperature will form a liquid-phase system from multiple components and will not require additional solvent) will continue to be withdrawn from the reaction zone, also after granulation.

Since U performs a "service role" (reduces the transition Pu in NCF head on stage), it must susilowati, i.e. translate by known methods in the fine oxide and pass in the head process (fluoridation).

Then each of the remaining products (possibly through a phase of temporary storage) sent for recycling in accordance with the technological task, mainly for the production of fuel compositions of Fe AR. It is possible that many known ways to obtaining alloys, individual metals, oxides, nitrides; when combined fuel components with MA (in particular, with U Np), PD (for their transmutation) how direct is in the process of receiving, and for subsequent mixing with manufacturers of fuel rods, perhaps. and the individual receiving MA for their exposure in the form of "targets". Chemical and physico-mechanical condition of intermediate products (anoxic granular soluble in the molten salt without chlorination) allows you to organize high-performance continuous processes for the production of fuel compositions.

To well-known advantages of pyrochemical processes (a small number of operations, the minimum amount of waste in handy for future reference chemical and physical form, intrinsic safety) is added the possibility of continuous high-performance processes in devices of resistant materials. The proposed method allows to process several types of fuel chemical composition and get practically any kind (universal technology for input products and its flexibility for the production of all fuels and fuel compositions). Permanent support of the most attractive fissile material (Pu) high-level PD and partial purification from them on the final stages of production (oxide, nitride, metal) add to its protection from unauthorized use.

Installation for the implementation of the proposed method differs from the known fact that the at includes 3 of the apparatus, designed for continuous operation. The transfer of solid products (powders) between them are planned to be performed by known methods (storage hopper and dispenser feeder or pneumatic transport, if it is not possible to place the units on top of each other).

The sequence of their placement on the technological chain, functions, input products and reagents, the movement of products and recycling of the reagents is shown schematically in figure 1.

Apparatus 3 performs the functions of charator (3A), condenser (3b) and pellet (3b), it can also (for certain tasks) to perform the role of the head unit.

XLERATOR is a host fiery apparatus comprising a feeder for feeding powder oxides, devices for supplying gaseous and fine particulate reagents and additives (not shown). These solutions are known, and the present invention does not make them essential attributes.

The capacitor serves as the inner surface of the walls of chlarotera, divided into zones and sub-zones (areas). Areas or zones provided by individual devices to maintain the desired temperature (cooling or heating). Each section (or area) is provided with a tapered shoulder and outputs fused chlorides in the form of holes and piping elements for heating. Flare zone and expands the rhenium gases made in the form of a body of rotation, reminiscent of incomplete in the upper part of the pear, which is in the lower hemisphere of the infundibular recess. "Pear" is docked to the cylindrical part of charator for exit gases is provided an annular gap, sufficient to ensure their "moderate" speed (of the order of 0.1-1.0 cm/s).

Placed along the Central axis element of the device, ending with a nozzle equipped with a heater (not shown) for creating the outer surface temperature is higher than at the same level opposite wall, while none of chlorides on it does not harden.

Division of condensation zones II and III areas have "shoulder", allows you to display the condensation products as a separate (optional) parts and join them from several sites, including the entire zone.

For granulation, a device for crushing of liquid chlorides in drops and containers with boiling liquid (not shown), in which the drops fall and harden in the form of granules. Can be used and other known device for pelleting (cooled rolls for solidification and crushing device for the organization relative movements of the drops and the cooling gas and others).

The plot on the path of the droplets of the melt from the nozzle to the surface of the CCl4must be sealed and completed the Yong an inert gas (N 2Ar) or in pairs CCl4.

Next, a device to extract granules, drying and transportation for use or temporary storage (not shown).

In the operation of charator-condenser-granulator possible conditions under which part NKh may withdraw from the condensation zone. On the path of the exhaust gases prior to their separation provided by the control trap with intensively cooled container, which includes a nozzle, the inlet gases. The container can be removed from the cooling receptacle for emptying. So at this time there was no leakage of gases and NCH, provided by the presence of two control traps with the ability to switch the flow of gases from one to another.

Apparatus and devices for further operations for the production of fuel (or other purposes) to be known, that is, the proposed solution does not make them distinctive attributes.

In figure 1, where the right-hand side is reduced operations (essential features), not containing solutions ("uranium division), and in left - operations with distinctive features, briefly presents a schematic process flow diagram of the proposed method, including three consecutive apparatus of continuous operation, the second and the third of them is fierce. For simplicity's sake, "big is lachno" given such operations as Cleaning UF 6", "Recirculation F2", "Getting target products: PuO2, PuN,

Pumethalloy Pu" and others, because the proposed solution does not make them distinctive attributes.

Figure 2 shows the principle arrangement of the third apparatus - charator-condenser-granulator (HKG) with the location of the condensation zones: I - high-boiling chlorides (WSU); II - chloride with an intermediate boiling point, and III - a low-boiling chlorides (NCH). The coupling between the element located along the axis of the apparatus, and the top of the condensation zone is made maximally extended to reduce the mutual thermal influence. As the cooling and condensation of gases and vapors decreases in volume, and the "living" section of the flow of gases can be reduced. This explains the General configuration of the apparatus. The Central element of the device through which skipped tube and feeder input products, reagents and additives (not shown) has an additional heater to prevent condensation of any of chlorides on the surface.

The ratio of the diameters (parts of machine) and height should be selected with consideration as to the flow velocity of gases (decrease temperature "washout" zones of condensation of individual components or groups of them), and thermal conductivity of the material of the device to provide enough "about try heating, i.e. the local heating mode, similar to the regime of the zone melting process.

Figure 3 schematically shows a device "control" trap NKh that can go from the condensation zone of charator when unloading the top, least of heated area.

Provides cooling slot of the container, extracted down. Because condensation will occur from wet gas, and some NK - hygroscopic, simultaneously with the solid condensate may be present liquid fraction hydrates. For ease of unloading the container may be made of a corrosion-resistant elastic material (plastic, rubber and other), including disposable ones. A variant of the container with a liquid valve for circumstances, when will prevail liquid fraction, and the discharge can be carried out without stopping the process.

The implementation of the method

1) For processing taken ~2000 kg SNF PTH. After cutting rods, voloxidation, separation from shell scraps and recovery (a combination of dissection and grinding) fine oxides of U, Pu and PD are served on fluoridation in the reactor operating in a continuous mode with a capacity of approximately 100 kg/h

Comparison of thermochemical reactions

and

shows that the change in free energy ∆ 0 1000(at 1000K) for reaction (5) is higher than that for reaction (6) in ~3 times. [Kiewicz, Pueblo. Thermodynamic properties of 65 elements, their oxides, halides, carbides and nitrides. - M., metallurgy, 1965] If according to reaction (6) the productivity of a manufacturing apparatus is 450 kg/h [Proceedings of the Second International conference on peaceful uses of atomic energy (Geneva, 1958). Selected papers from international scholars, Vol.7. The technology of nuclear materials. M, Atomizdat, 1959, s. Powell. Modern processes used in the United States for mass production UF6], the performance adopted in our example (100 kg UO2/h), are achievable.

Forgent enter this value to ~0.1 to 0.5% of the initial amount of U remained in VCOP together with Pu. The bulk NCF, including U and many DD, taken in the gaseous state to the division Clearing UF6" and then to adjust the mass fraction235U (if necessary), then repartition of the production of target products.

VKOF pass to a redistribution of re-conversion into oxides in continuously working flaming apparatus of pyrohydrolysis performance ~4 kg/h Own heat of reaction Q1not enough, therefore, impose additional N2and O2for energogazovaya reaction (2). As a result, at this stage, get melodizer the major oxides of U, Pu and PD, passed on division chlorination condensation-graining" with a continuously running fiery apparatus chlorination. Because the performance of ~3.5 kg/h own heat of reaction Q3not enough, additionally injected reagents Cl2and H2for energogazovaya reaction (4), and to keep U in the tetravalent state in the torch together with gaseous H2serves fine powder UH3.

To facilitate withdrawal of the WSU PD (and PuCl3from the first condensation zone in the dog gave granules NaCl. Forming with each other and with NaCl complex less refractory salt system, WSU PD (and PuCl3) "gravity" leave the condensation zone, and then subjected to granulation.

More low-boiling reaction products in gaseous state rise up (velocity of about 0.1-1.0 cm/s) and at least reduce the temperature of the walls of the apparatus are condensed on them. Excess non-condensable gases along with the remnants of chloride PD (in the form of aerosols) leave the device, are the reference trap and sent to the purification, separation and recirculation. For discharging the capacitor from areas where it condenses U and PD in the solid state, conduct periodic heating of the walls up to full melting of condensates and their flow in the device to dripping and forth in the tank with the liquid diazetidine (granulation).

Granular intermediate products (a number from 2 to 10, depending on the task processing) are sent to the respective stages:

the fraction containing the largest amount of uranium - to obtain uranium oxide (by known methods) to return to the head process (fluoridation) or to obtain compositions U-MA (for their transmutation);

the fraction containing the largest amount of plutonium - production of target products (oxide, nitride, metal, alloys with other metals). At the same time obtaining the desired products produce clean PD by known methods. Anoxic condition of intermediate products (uranium tetrachloride and trichloride PU) allows you to organize continuous process for the production of any of these target products on an industrial scale.

For 20 hours of continuous operation revised 2000 kg SNF PTH data products:

- uranium hexafluoride high purity, from which another 20-50 hours (if necessary, re) can be produced ~1900 kg UO2(method of pyrohydrolysis fluidized bed with the electrode), suitable for the manufacture of fuel rods PTH technology of vibrocompaction;

- trichloride plutonium mixed with PD and MA, which through 20-50 h (needs cleaning) can be produced ~20 kg PuO2(krupnikas lichecki powder), suitable for the manufacture of fuel rods of the reactor RBN and PTH technology vibration compaction using the method of simultaneous dosing;

- ~20 kg UO2intended to return to the head of the process;

- ~60 kg PD in circulating chloride salts and fluoride in the waste-gas processing.

2) For processing taken ~500 kg of SNF RBN. After the release of fuel from structural materials (known techniques) and mechanical grinding until the particle size of ≤0.1 mm fuel serves on fluoridation in the reactor operating in a continuous mode with a capacity of approximately 20 kg/hour, Forgent injected with the same ratio to ~1.5% of the initial amount of U remained in VCOP together with Pu. The bulk NCF, including U and PD, is directed to a gaseous state to the division Clearing UF6" and next on the repartition of the production of target products.

VCOF (including fluoride Pu and partially U) passed on the repartition of the re-conversion into oxides in continuously working flaming apparatus of pyrohydrolysis performance ~4 kg/h Own heat of reaction Q1for intense burning torch is not enough, therefore, impose additional H2and O2for energogazovaya reaction (2). As a result, at this stage receive fine oxides of Pu, U and DD, who served on the division chlorination condensation-granuloma the ie" with a continuously running fiery apparatus chlorination. Because the performance of ~3.5 kg/h own heat of reaction Q3for intense burning torch is not enough, additionally injected reagents Cl2and H2for energogazovaya reaction (4), and to keep U in the tetravalent state in the torch together with gaseous H2serves fine powder UH3.

Significant amount of Zr in the SNF RBN leads to condensation ZrCl4in the solid state. For its dissolution and withdrawal from the zone of condensation on the shelves of the relevant sections of the injected melt fusible salt 3LiCl-2KCl.

Also use an option to increase the oxidative capacity of the environment by adding the share of Cl2while Uranus transits in a valence state of +5 and +6, the sum of these chlorides condensed in the same zone, where and ZrCl4they fused liquid leaving the condensation zone.

Because the majority of the resulting chloride is PuCl3you do not need to enter into the area of the first capacitor additional additives to reduce the melting temperature of the complex salt system, and the products of condensation zone I "gravity" leave it to conduct granulation. More low-boiling chlorides in the gaseous state rise up and at least reduce the temperature of the walls of the apparatus are condensed on them. Excess non-condensable gases instead of the e unfused residues (as well as in the form of aerosols) leave the apparatus, pass control to the trap and are directed to the purification, separation and recirculation. For discharging the capacitor from zones II and III, where it can condense U and PD in the solid state, conduct periodic heating of the walls up to full melting of condensates and their flow in the devices drop (granulation).

With granulated intermediate products do the same, as discussed in example 1.1.

Over 25 hours of continuous operation processed 500 kg of SNF RBN, with the resulting products:

- uranium hexafluoride high purity, from which even after 20 h can be made ~370 kg UO2(method of pyrohydrolysis fluidized bed with the electrode), suitable for the manufacture of fuel rods RBN technology of vibrocompaction;

- trichloride plutonium mixed with PD and MA, which through 20-50 hours (depending on the required cleaning)can be ~75 kg PuO2(coarse powder), suitable for the manufacture of fuel rods of the reactor PTH and RBN technology vibration compaction using the method of simultaneous dosing;

- ~7.5 kg UO2intended to return to the head of the process;

- ~50 kg PD in circulating chloride salts and fluoride in the waste-gas processing.

3) For processing taken ~2000 kg UO2(dump isotopic composition) of the area of reproduction RBN. Further description of the sample coincides with example 1.1, differing only in the number of PD and Pu, why the amount of operation of the apparatus for processing Pyrohydrolysis and Chlorination-condensation-graining" decreased ~2 times.

As a result, over 20 hours of continuous operation is received:

- uranium hexafluoride high purity for the production of circulating UO2area the reproduction;

- ~30 kg trichloride plutonium mixed with PD, which can be aimed at the redistribution of production of target products, as in examples 1.1 and 1.2;

- ~20 kg UO2intended to return to the head of the process;

- ~10 kg PD in circulating chloride salts and fluoride in the waste-gas processing.

Implementation of installation

The installation includes: three models of continuous action for fluoridation, pyrohydrolysis (flaming), chlorination (flaming, followed by condensation and granulation) with independent power systems, life support, recycling of reagents, control and management of technological processes and transport streams; processing equipment Cleanup UF6", "Pyrohydrolysis UF6", "Production of target products with a full range of systems to ensure their health. Provides for redistribution of pyrohydrolysis chlorides of uranium back the obtained uranium dioxide in the head in the process.

Not having similar is in the device installation is XLERATOR-condenser-granulator", which of the fine oxides of Pu, U and DD get anoxic chlorides, due to different vapor pressure which it is possible to arrange the separation of U and Pu and their partial exemption from DD.

1) Apparatus for organizing condensation in the solid state is a cylindrical body with a base at the bottom. In the center of the cylindrical body are pipelines to supply to the nozzles of the input product, reagents and additives. Piping (not shown) enclosed in a common casing of conical shape, which is simultaneously the heater to prevent condensation of any of the possible chlorides in the solid state. The transition between these heated and cooled upper part of the body is maximally extended to reduce the mutual thermal influence. The base is designed as an extension in the form of a "pear" with funnel-shaped recess on the lower hemisphere, inward. A device for feeding additives NaCl in solid or molten form (not shown), salt falls into the same zone, where is the torch burning. Cylindrical body inside has several shoulder forming an annular funnel (grooves) with outputs in the system granulation. The height of each rib is selected such that the circumference of the inner edge of the EAP who was described in the circumference of the inner edge of the upper flange. This is necessary so that when the collapse of the solid product between the shoulder (after slight melting of the part adjacent to the heated wall) portion of the product has not fallen down. Each wall section between the shoulder or more of these areas (zone) has the possibility of additional heating (cooling).

The ratio of the size ratio of the diameters of the Central element and the height of the flange is selected such that the "right" way to organize the movement of gases.

Gases (and heating) in the torch, first have the opportunity to expand in the lower zone (base), reduce speed and change direction (this part of the mass is condensed, which also leads to reduction of pressure and gas velocity. To accelerate the condensation of water in the Central part of the base (in the area of the crater, inside which is a conical elevation) provided a zone of intensive cooling through the outdoor heat exchanger. To reduce the turbulence of the gas flow nozzle head enclosed by a cap in the form of a bell.

The annular gap between the Central part of the apparatus and the inner edge of the lower flange is a "living" section that are contained in the gases had moderate speed (without capture liquid drops of water). Further decreasing the temperature of the internal walls of the building is a and weight loss and gas volume due to condensation of chloride velocity of the gases is reduced, to reduce the living section of the overlying areas of the body.

In each zone (area) condensation provides an output product. For this purpose made holes in the housing with heated pipelines (Pets their connection header in the group). Next, a device drop (not shown), and separate liquids for solidification of the droplets (granulation), device for extracting, drying and packing (transportation) pellets (not shown). The outside of the case there is a system of supplementary heating (cooling) of the wall (not shown)that creates a smooth change in temperature of ~800°C in the condensation zone I to ~40°C in the area of the exit gases from the shell.

The material of the device is selected such that the frequency of its replacement was not made a significant contribution to the cost of reprocessing spent fuel. The ratio of the material characteristics (thickness and conductivity) and the external heater (coil) allows "acute" additional heating areas that are close to the regime to zone melting.

2) the Apparatus for organizing condensation in the liquid state is different from example 1 in that in the discharge piping, a device for maintaining the level of liquid (not shown), allowing it to partially flow through the shoulder. In this example, when is the work apparatus with continuous withdrawal of products you can implement mode, approaching rectification.

3) depending on the type of SNF and modes of condensation in the apparatus HCG the composition of the exhaust gases (mass fraction of condensed impurities) is different, so you can use two options control traps:

3.1 collection "sublimates" solid trap consists of infeed and exhaust gas cooled socket and the container. Jack and the container is hermetically connected by a conical surface, made with strictly the same inclination to the axis, which creates a tighter fit for efficient heat transfer. The container is partially filled with condensate containing a solid fraction, extracted from the socket and replace the CSO free.

3.2 In the case when the solid fraction formed in small quantities, the trap is provided with a stationary container provided with a water seal that allows you to remove condensate without depressurization of the trap.

1. Method of reprocessing spent nuclear fuel containing uranium and plutonium, including stage fluorination of the fuel with the transfer of uranium hexafluoride, in addition to quantity, sufficient to hold all of plutonium in high-boiling residues fluoridation, separate processing of uranium hexafluoride to clean it from the low-boiling products division with further transformation into fuel components and Vysockij the residues fluoridation for the extraction and use of plutonium and other valuable components, wherein the high-boiling residues fluoridation consistently turn first to the oxide, and then glorious at high temperature, the resulting chlorides for their separation and partial purification of plutonium condense in zones with different temperatures.

2. The method according to claim 1, characterized in that the conversion of high-boiling residues fluoridation in oxides spend pyrohydrolysis fiery device with additional energogazovaya reaction of the combustion of hydrogen in oxygen.

3. The method according to claim 1, characterized in that the chlorination of oxides after their conversion is carried out in a fiery apparatus using hydrogen chloride with additional energogazovaya reaction of the combustion of hydrogen in chlorine.

4. The method according to claim 3, characterized in that the redox ability of the environment to manage the changing attitudes of hydrogen to chlorine.

5. The method according to claim 3 or 4, characterized in that the combustion zone of the flame to impose an additional reducing agent in the form of sodium vapor, or fine powder of uranium (in the metallic state), or trihydride uranium, or trichloride uranium.

6. The method according to claim 3, characterized in that the condensation of chloride is carried out from the area around the torch and forth from the upward flow of gases (in order of decreasing temperature) in zones (areas), of which the organized destruction of products.

7. The way is about to claim 6, characterized in that the condensation is carried out in the solid state, to output products periodically melted chlorides and divert them from the condensation zone.

8. The method according to claim 6, characterized in that the condensation is carried out in the solid state, and to transfer the product into a liquid state on the appropriate shelf serves low-melting chloride salt.

9. The method according to claim 6, characterized in that the condensation is carried out in the liquid state with continuous removal of products.

10. The method according to claim 9, characterized in that the partial organize the flow of liquid through the shoulder with the overlying sections on the underlying.

11. The method according to claim 6, characterized in that inferred from the condenser products granularit by dripping and their solidification in boiling non-flammable liquids.

12. The method according to claim 6, characterized in that from a pre-selected group of chlorides with trichloride produce plutonium fuel components with additional removal of fission products and the possibility of continuous processes.

13. The method according to claim 1, characterized in that after the operation of chlorination and separation of chloride of uranium into uranium oxide and as current product return on fluoridation.

14. The plant for the reprocessing of spent nuclear fuel containing uranium and plutonium, includes three series is placed downstream of the device (for fluoridation, pyrohydrolysis high-boiling residues fluoridation and chlorination of oxides after pyrohydrolysis, then condensing and granulation) with the possibility of continuous operation, and the last two - flaming; processing equipment for cleaning and adjustment of the isotopic composition of uranium hexafluoride, the production from it of the fuel components; equipment for processing of a mixture of trichloride plutonium with some fission products (after its separation from residual uranium and other fission products in the fuel components with partial removal of fission products; equipment for recirculation of the reactants and for the sustenance of each stage.

15. Installation according to 14, characterized in that the third device (XLERATOR-condenser-granulator) the first condensation zone is made with an extension in the form of a pear, with funnel-shaped recess in its lower hemisphere, from the bottom point has a yield of liquid products of condensation, a cylindrical surface zones of condensation provided with a shoulder dividing it into sections, each of which has access through the openings in the case.

16. Installation according to item 15, wherein the flange is made conical, the upper edge is horizontal, and the lower inclined with one hole at the bottom for full flow of fluid when stopping the machine.

17. At the stop indicated in paragraph 15 characterized in that the outputs of the sites are equipped with heaters to keep products in liquid form with the possibility of combining them in the headers.

18. Installation according to item 15, wherein XLERATOR capacitor pellet mill has a device for dripping and solidification of the drops in boiling non-flammable liquid extract granules, drying and transportation.

19. Installation according to item 15, wherein after charator-condenser-granulator on the way gases are provided intensively cooled control traps with the possibility of removal of the condensation products of them.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: group of inventions concerns application of polymer-containing solution or water suspension paste and a device of ruthenium collection in gaseous discharge. The solution or water suspension paste contains one alkylene glycol polymer and/or one alkylene glycol co-polymer. The alkylene(s) contains 2-6 carbon atoms for ruthenium collection in gaseous discharge. The device includes a ruthenium collection cartridge with a substrate bearing alkylene glycol polymer or co-polymer. The alkylene(s) contains 2-6 carbon atoms.

EFFECT: improved ruthenium collection and chemical recovery of ruthenium oxide.

22 cl, 8 dwg

FIELD: nuclear engineering.

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EFFECT: enhanced durability of equipment.

3 cl, 4 dwg

The invention relates to methods of non-aqueous dissolution of uranium and uranium-containing materials and can be used to extract uranium from spent nuclear fuel, metallurgical wastes of uranium and its alloys and products

The invention relates to the field of production and processing of nuclear fuel

The invention relates to nuclear energy, in particular to the production of plutonium metal and mixed uranium-plutonium oxide fuel

The invention relates to the field of processing of irradiated and defective nuclear fuel, in particular mononitrides uranium-plutonium fuel

FIELD: nuclear engineering.

SUBSTANCE: proposed method for volume crystallization of plutonium dioxide includes treatment of molten alkali-metal chlorides with plutonium compound dissolved therein, as well as treatment of melt obtained in the process by oxygen-containing gas mixture and precipitation of large-crystal plutonium dioxide on bath bottom. In the process closed-porosity graphite granules are disposed on melt surface, their contact with melt being afforded as they are consumed. Apparatus for volume crystallization of plutonium dioxide from molten alkali-metal chlorides with plutonium compound dissolved therein has bath, cover, melt mixing system, and device for feeding soluble plutonium compounds and gas mixture to melt. Bath, parts and assemblies contacting the melt are made of ceramic material shielded at melt boundary level with pyrographite parts. Gas mixture feeding devices have ceramic and pyrographite tubes.

EFFECT: enhanced durability of equipment.

3 cl, 4 dwg

FIELD: chemistry.

SUBSTANCE: group of inventions concerns application of polymer-containing solution or water suspension paste and a device of ruthenium collection in gaseous discharge. The solution or water suspension paste contains one alkylene glycol polymer and/or one alkylene glycol co-polymer. The alkylene(s) contains 2-6 carbon atoms for ruthenium collection in gaseous discharge. The device includes a ruthenium collection cartridge with a substrate bearing alkylene glycol polymer or co-polymer. The alkylene(s) contains 2-6 carbon atoms.

EFFECT: improved ruthenium collection and chemical recovery of ruthenium oxide.

22 cl, 8 dwg

FIELD: fuel systems.

SUBSTANCE: invention is related to recycling of return nuclear fuel (RNF) and materials of blanket region (BR) of fast breeder reactors (FBR) for their multiple use with the possibility to adjust content in creation of a new fuel composition. Initial chemical state of processed material may vary: oxides, nitrides, metals and alloys. Method represents a combination of serial processes of chemical transformation of radiated nuclear fuel (RNF): fluoridation with gaseous fluorine and extraction of main uranium mass; transition of fluoridation remains into oxides (pyrohydrolysis); - chlorination of oxides in recovery conditions with group separation of plutonium chlorides, uranium (left in process of fluoridation) and fission products. Further "plutonium" and "uranium" fraction, and also fraction containing fission products (and, possibly, minor-actinides), are used each separately in various processes according to available methods. Earlier produced uranium hexafluoride, with low boiling fluorides of fission products, is cleaned from the latter and used, according to objectives of processing, also by available methods. Using waterless processes with application of salt melts, suggested version makes it possible to realise continuous highly efficient processes of fuel components production, moreover, it is stipulated to carry out preparation stages in continuous mode. Plant for processing of spent nuclear fuel containing uranium and plutonium includes three serially installed devices: fluoridiser; pyrohydrolysis device; chlorinator-condensator-granulator device. Two last devices are of flame type. The last of devices represents a pipe with a central element, in which lines of inlet product and reagents supply are installed. In lower part there is an expansion in the form of pear with a flame burner along its axis, and medium part has a row of conical shelves inside, between which there are nozzles with pipelines for chlorides outlet. Nozzle for chlorides outlet is also arranged in lower point of pear-like part. Nozzle for exhaust of non-condensed gases is provided in upper part. Granulator is arranged as reservoir with low boiling incombustible liquid, and to produce drops, capillaries are provided at pipeline ends.

EFFECT: highly efficient method for processing of spent nuclear fuel of practically any composition from thermal reactors and fast breeder reactors, blanket region of fast breeder reactors and some other types of reactors with the possibility to produce several other types of fuel compositions.

19 cl, 3 dwg

FIELD: metallurgy.

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EFFECT: higher yield.

2 tbl, 2 ex

FIELD: technological processes.

SUBSTANCE: invention relates to a method and a device for bringing two immiscible fluids into contact. Method of binging into contact without mixing of the first substance consisting of metal or alloy of metals in liquid state and the second substance consisting of salt or salt mixture in liquid state, in which: the first substance in solid state is placed in the first container, the first container is put into contact with the second substance in solid state placed in the second container, the first and the second containers are exposed to electromagnetic field effect, the first substance in liquid state is brought into motion, the second substance in solid state starts melting under the effect of heat flow from the first container, the second substance in liquid state is brought into motion, the first substance in liquid state stays in contact with the second substance in liquid state for a certain period of time, the first container is removed from the second substance in liquid state, the first container is cooled until the first substance returns into solid state.

EFFECT: improved mass transfer kinetics.

35 cl, 10 dwg, 2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing oxychloride and/or oxide of actinide(s), and/or lanthanide(s) from chloride of actinide(s), and/or lanthanide(s), present in a medium containing at least one molten salt of chloride type. Method involves a step for reacting chloride of actinide(s) and/or lanthanide(s) with wet inert gas.

EFFECT: invention provides efficient production of oxyhalogenide and/or oxide of actinide(s), and/or lanthanide(s), as well as formation with elements of actinides or lanthanides, products, different from oxyhalogenides or oxides, and excluding cation-contamination of medium containing molten salt, simplifying recirculation of molten salts.

11 cl, 3 ex

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