Treatment of carbon-containing radioactive wastes

FIELD: power engineering.

SUBSTANCE: subject of this invention is the method of treatment of carbon-containing wastes. In particular, the following is provided: the first type of treatment for production of carbon oxide, and the second type of treatment for production of solid residue of carbon oxide by means of reaction with the chosen element. The method in accordance with this invention includes: the first stage, during which the first and second types of treatment are applied simultaneously, and the second stage, during which only the first type of treatment is applied.

EFFECT: invention makes it possible to reduce quantity of solid residue.

31 cl, 2 dwg

 

The present invention relates to the processing of carbon-containing radioactive waste, such as graphite structure ("covers"surrounding the Assembly of nuclear fuel elements, or "blocks"that acts as a reflector or moderator), or an organic resin (often in the form of pellets or tablets), used to capture other radioactive waste, in particular, in the reactors of nuclear power plants.

In these carbon-containing wastes should be isolated and stored under conditions of integrity volatile radionuclides, such as tritium (3N), chlorine 36 (36Cl), and carbon isotopes, in particular radioactive isotope14(Hereafter referred to as "carbon-14").

There are two types of processing such carbon-containing waste:

the first type of processing to produce carbon monoxide, for example monoxide and/or carbon dioxide, in which the element carbon is the isotope carbon 14, and

the second type of processing of the carbon monoxide to obtain a solid residue by reaction with the selected element, such as calcium.

This second type of processing called "the formation of carbonate is, for example, in the formation of bubbles of carbon monoxide in a solution containing quicklime (when the selected item is a calcium), and the resulting solid precipitate (as a rule the ILO calcite, carbon which is an isotope14C) can be isolated and stored in bulk for a long time in the containers stored on the surface or buried under the ground at a certain depth, for example in the boneyard. It should be noted that in this embodiment, the reaction of carbon monoxide can be done with another element other than calcium, such as magnesium (or other metals), to obtain magnesia MgCO3. It should be noted that this second type of processing, as a rule, is designed to produce insoluble solid precipitate carbonates and/or salts containing carbon.

Usually the second type of processing used for any carbon monoxide resulting from the first treatment. So, get a solid residue from any of the carbon monoxide resulting from the processing of waste.

This solution is not satisfactory for at least two reasons. On the one hand, processing, storage and disposal of sediment (calcite or other) are very expensive. On the other hand, with regard to the requirements of environmental protection seek to minimize waste storage (especially if they can destroy or process).

The present invention aims to improve this situation.

In this regard, the invention proposes a method containing:

the first stage, during which apply both the first and the second type of processing, and

the second stage, during which apply only to the first type of processing.

Indeed, it was found that the radioactive isotope14With, perhaps because of the nature of its nuclear ties has properties different from the properties of non-radioactive carbon12With and possibly other properties of the isotope13(Hazardous or non-hazardous), and willing to respond faster than other isotopes of carbon, when using the first type of processing.

The explanation of this phenomenon is presented below. In a reactor thermal neutron flux isotope14With the results from the two reactions are:

the first reaction13With (n,γ):14C and

- second reaction14N (n,p):14C.

The first reaction prevails over the second, because the carbon is preferably a graphite matrix, whereas nitrogen is mainly found in the pores of the graphite.

The calculations showed that the recoil energy of the isotope14With that obtained with two types of reactions is sufficient to break chemical bonds in the crystal lattice plane of graphite. Indeed, as a rule, the binding energy higher than 1 Kev (for isotope14C derived from isotope13C) and is approximately equal to 40 Kev (for isotope14C, developed the CSOs from isotope 14N). Therefore, there is a high probability that the relationship is C-C planes of the crystal lattice of graphite, the energy which is approximately equal to 280 eV, will be torn to atoms of the isotope14C and that these atoms will be displaced from their structural nodes. In the reactor, these atoms can re-establish a connection with the carbon atoms or impurities of the graphite, but in this case, the operating temperature of the reactor will not be enough to restore the crystal lattice plane of graphite.

Thus, during the above first and/or second processing isotope14C tends to release before isotope12C.

In other words, in the first stages of processing waste oxidation is first provided mainly carbon monoxide, carbon which largely contains the radioactive isotope14C; then get monoxide, carbon which is maloradioaktivnomu or is not radioactive, as it mainly consists of12C. it is Clear that this is not radioactive carbon monoxide can be removed directly into the atmosphere without treatment to obtain a solid residue.

Thus, in the method in accordance with the present invention, when the carbon-containing wastes initially contain carbon 14, the solid residue obtained from the first stage, basically which contains carbon 14, while the carbon monoxide produced in the second stage, does not contain carbon 14 or contains only a residual amount, that is, it can be deleted directly. Carbon monoxide after the second stage can directly delete the atmosphere (or can be processed, for example, by oxidation to obtain carbon dioxide, in order to avoid removal of carbon monoxide in the atmosphere).

The most suitable time for transition from the first stage to the second stage and the removal of carbon monoxide in the atmosphere can be determined as follows:

- measure the amount of radioactivity in the carbon monoxide obtained after applying the first type of processing in the first stage, and

- decide on the beginning of the second stage, if the amount of radioactivity is less than the selected threshold value.

However, for the successful implementation of this operation, you must ensure that at the first stage of processing radioactive can only be carbon monoxide. However, the processed waste can contain other volatile radioactive elements other than carbon, such as tritium (3N) or the isotope chlorine 36 (36Cl) or other. Usually the preferred embodiment of the method according to the invention, the waste is shredded and sent for wet processing methods, that do not contain carbon radioactive elements isolated the comfort and the wet process method, while the carbon monoxide is removed from a wet method in volatile form. Preferably used is located in the appropriate place in the analyzer of radioactivity. In this case, preferably the amount of radioactivity in the carbon monoxide is measured by analyzer located outside the wet method. This analyzer can measure β-activity of carbon 14, which may be contained in eye-catching carbon monoxide resulting from the first type of processing.

It should be noted that the above-mentioned first type of processing is intended for the decomposition of the waste with the purpose of obtaining carbon monoxide, as a rule, co or CO dioxide (CO2. Currently in the processing of radioactive waste there are various ways of getting carbon monoxide:

- steam reforming, described in particular in document US-2002/064251,

or heating in an inert gas.

Steam reforming is a treatment with water vapor at high temperature according to the reaction C+H2O→CO+H2, which is preferably carried out at a temperature greater than or approximately equal to 900°C. and most preferably at 1200°C and above, which will be shown below.

Heating in an inert gas (e.g. nitrogen (N2also preferably carried out at a temperature greater than or the ome 900°C and most preferably at a temperature of 1200°C and above according to the reaction C+½O 2→CO and/or C+O2→CO2and/or according to the above reaction C+H2O→CO+H2water produced from wet process (in the aquatic environment).

In the context of the invention is, in particular, carrying out the reaction at temperatures above 900°C (i.e. the temperature normally used for these reactions), as it was found, as will be described in detail below with reference to figure 2 that the effect in which the carbon 14 reacts had not radioactive carbon12For the oxide formation WITH or CO2manifests itself stronger, the higher the reaction temperature (and, in General, carbon-containing waste). Preferably the apparatus for waste treatment method in accordance with the present invention using a furnace in which the temperature is 900°C may be exceeded.

In addition to using the analyzer radioactivity of the carbon monoxide formed during the first stage, preferably also used nomograms that allow depending on the temperature of the oxidation reactions to determine the point at which emit carbon monoxide can be removed in the atmosphere. In this case, from the first stage to the second stage can proceed at a time determined at least:

- initial quantity of processed waste, and

- temperature oxidation reactions during the applications of the first type of processing.

In addition, the processing of the oxidation of carbon, it is preferable to start with:

- heating process in an inert gas (with the formation of carbonate to obtain carbon monoxide without dropping into the atmosphere), and

- processing of waste to continue the process of steam reforming with the formation of carbonate only in a certain period of time before the next free removal of carbon monoxide in the atmosphere).

Thus, in the first stage, the first type of treatment involves heating in an inert gas and in the first and second stage steam reforming.

The object of the invention is also an installation for processing carbon-containing radioactive waste, the installation includes means for application of the method in accordance with the present invention. These means will be described in detail below.

Other distinctive features and advantages of the present invention will be more apparent from the following detailed description with reference to the accompanying drawings, on which:

figure 1 - diagram of equipment for waste processing in accordance with the present invention;

figure 2 - change in the amount of carbon 14 that is formed in the form of oxide, depending on the time at different respective temperatures of the reaction.

As shown in figure 1, the crusher BR grinds graphite (usually up to grain size is of the order of centimeters) in water. The number of carbon-containing waste Q is transported through a wet method (N2O) in the first furnace, in this case, a heating stove for the first operation of oxidation called oxidation in an inert gas, preferably at a temperature of 1200°C. In a furnace FO1 can be a reaction of the type:

C+α/2O2→COαwhere α=1 or 2.

Then use the reaction of formation of carbonate type:

X(OH)2+CO2→HSO3+H2O, where X=Ca or Mg or other item, for example, by the formation of bubbles in the lime milk (in this case X=Ca).

It should be noted that the possible formation of carbonate consists in the application of isotope separation of carbon, as described in document JP-2000070678.

However, more preferred is the formation of carbonate, as in the formation of calcite from lime milk (X=Ca) during the year, receive only a few m3carbonate, which can be stored for a long time (for example, by burial in the appropriate place). At this stage, about 30% of carbon-14 contained in the graphite waste that has already been processed. In addition, at this stage, the handle 80% of the tritium. If necessary, the step of heating can be repeated in several cycles to handle the maximum number of source waste with carbon 14, decontaminate at this stage.

Additional amounts of waste Q' (Q'=αQ, where α<1) through the same wet process (H2O) take the second furnace FO2 for direct application of the invention. In this second furnace FO2 use the steam reforming reaction, which is:

C+H2O→CO+H2

This reaction is preferably carried out at a temperature of 1200°C or more by injection of hot steam. Then at the first stage, collect the carbon monoxide with the purpose of obtaining a precipitate of carbonate XCO3(for example, with milk of lime, and in this case X=CA). It should be noted that due to the method in accordance with the present invention, the amount of carbonate in the form of solid waste destined for disposal under the land, is only a few hundred m3/year by optimizing the point at which the formation of carbonate can stop and move on to the second stage, in which the carbon monoxide (a gas) directly removed in the atmosphere.

In particular, in a variant application of the invention the analyzer β-radiation outside of the wet channel, detects in eye-catching carbon monoxide carbon 14. If the analyzer detects AN carbon 14 below a given threshold THR (for example, about 1%) in eye-catching carbon monoxide, this eye-catching carbon monoxide can be removed directly in the atmosphere is the fer and the formation of carbonate can be terminated.

Measurement outside the wet method is preferred when other radioactive elements for processing, isolated in the wet and they don't get on stage steam reforming. This applies in particular to the tritium3N or chlorine36Cl, which can emit β-radiation, but they were isolated in the wet, and therefore an analyzer does not detect the radiation, and detects only the emission of carbon 14 that allows you to measure in real time the moment of transition from the first stage of formation of carbonate to the second stage of direct removal.

Finally, the treatment machine other radioactive elements other than carbon-14 (in particular, tritium and chlorine-36, cesium, cobalt, iron and other metals), which are extracted in a wet way for subsequent collection and long term storage.

Next, with reference to figure 2 should be an explanation of the advantages of heating operation (if necessary, in several cycles) and the operation of steam reforming at a higher temperature than in the known methods (in which the temperature can be close to 900°C and even below 900°C).

The inventors have found that carbon 14 predominantly reacts earlier than other isotopes of carbon during the reaction heat, and during the reaction of steam reforming. Obviously this effect is linked to the nature of atomic bond of carbon-14 in comparison with other isotopes. The effect is the stronger, the higher the temperature oxidation. As shown in Fi, curves, characterizing the number of the reacted carbon 14 have essentially convex shape (because the carbon 14 predominantly reacts with other isotopes), and convexity of the curves expressed greater, the higher the reaction temperature. Thus, rather than performing a reaction of all of the carbon monoxide to obtain warehoused in bulk carbonates set the threshold THR, below which the amount of carbon 14 that can go into the atmosphere as a gaseous oxide of carbon, is void or at least permitted by the relevant organizations, taking into account their impact on human health and on the environment.

This threshold THR is achieved much faster if the reaction temperature is high, as shown in figure 2. Thus, in the furnace FO2 more preferred are reaction temperatures of about 1200°C, compared with the known solutions, in which, as is known, apply a temperature of 900°C. If in the future the furnace will be able to afford, it is even more preferable would be even higher temperatures, such as 1500°C. In any case, it is noted that the time t1200°Cfor which the method can proceed from the stage of the formation of the carbonate to the stage free removal of carbon monoxide, much less p and high temperatures, than at low temperatures.

In addition, it should be noted that the convex shape of the curves describing the amount of carbon reacted in the form of oxide, depending on the time observed when the oxidation reaction heat and oxidation reactions of steam reforming.

However, in principle at the stage of heating in the furnace FO1 direct removal of carbon monoxide is not provided. In this regard, there is no transition to the second stage direct removal, and this operation is described in the example carried out by a process of steam reforming.

Of course, the present invention is not limited to the described variant execution is represented as an example; it covers and other options.

For example, in the way presented with reference to figure 1, the trapping of tritium or chlorine 36 is not described in detail since the invention relates to the processing of carbon-14 to carbon-containing waste. However, it was noted that these items remain in the water wet method.

In addition, at the stage of heating, it is possible to apply a variety of reactions such as C+α/2 O2→COαwhen α=1 or 2, or such as C+H2O→CO+H2while they, as a rule, lead to the oxidation of carbon. The water involved in the last reaction you get from the wet method (residual form). Finally, ledue is to be noted, unlike stage steam reforming, in which the waste is served heated to high temperature water vapor, stage heating effect on the waste by a simple oxidation, and high temperature (close to 1200°C or higher). It should also be recalled that stage of heating is preferably carried out in several cycles.

1. The method of processing carbon-containing wastes containing:
the first type of processing to produce carbon monoxide, and
the second type of processing to produce a solid residue of carbon monoxide by reaction with the selected item,
characterized in that it contains:
the first stage, during which apply both the first and the second type of processing, and
the second stage, during which apply only to the first type of processing.

2. The method according to claim 1, characterized in that the carbon monoxide resulting from the second stage is removed directly into the atmosphere.

3. The method according to claim 1, characterized in that the selected item is a calcium, a second type of processing is the formation of carbonate, and the solid residue obtained after the first stage is a calcite designed for packing for the long-term storage.

4. The method according to claim 2, characterized in that the selected item is a calcium, a second type of processing is with the battle formation of carbonate, and a solid residue, obtained after the first stage is a calcite designed for packing for the long-term storage.

5. The method according to one of claims 1 to 4, characterized in that:
measure the amount of radioactivity in the carbon monoxide resulting from the application of the first type of processing in the first stage, and
decide on the beginning of the second stage, if the amount of radioactivity is less than the selected threshold value.

6. The method according to claim 5, in which if the waste contains radioactive elements that do not contain carbon, they are crushed and sent to a wet process extract, not containing carbon radioactive elements are isolated and treated by a wet method, and the carbon monoxide is removed from a wet method in a volatile form and the amount of radioactivity of carbon monoxide is measured by analyzer located outside the wet method.

7. The method according to one of claims 1 to 4 and 6, characterized in that the first type of processing includes at least steam reforming.

8. The method according to claim 5, characterized in that the first type of processing includes at least steam reforming.

9. The method according to one of claims 1 to 4, 6 or 8, characterized in that in the first stage, the first type of treatment involves heating in an inert gas.

10. The method according to claim 5, characterized in that the first stage of the first type on which abode includes heating in an inert gas.

11. The method according to claim 7, characterized in that in the first stage, the first type of treatment involves heating in an inert gas.

12. The method according to one of claims 1 to 4, 6, 8, 10 or 11, characterized in that from the first stage to the second stage pass at a time determined at least:
the initial quantity of processed waste, and
the temperature of the oxidation reaction during the application of the first type of processing.

13. The method according to claim 5, characterized in that from the first stage to the second stage pass at a time determined at least:
the initial quantity of processed waste, and
the temperature of the oxidation reaction during the application of the first type of processing.

14. The method according to claim 7, characterized in that from the first stage to the second stage pass at a time determined at least:
the initial quantity of processed waste, and
the temperature of the oxidation reaction during the application of the first type of processing.

15. The method according to claim 9, characterized in that from the first stage to the second stage pass at a time determined at least:
the initial quantity of processed waste, and
the temperature of the oxidation reaction during the application of the first type of processing.

16. The method according to item 12, wherein the specified temperature exceeds 90°and preferably equal to about 1200°C.

17. The method according to item 13 or 14, characterized in that the specified temperature exceeds 900°C., and preferably equal to about 1200°C.

18. The method according to one of claims 1 to-4, 6, 8, 10, 11 and 13-16, in which carbon-containing wastes initially contain carbon 14, and the solid residue obtained after the first phase mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

19. The method according to claim 5, in which the carbon-containing wastes initially contain carbon 14, and the solid residue obtained after the first phase mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

20. The method according to claim 7, in which the carbon-containing wastes initially contain carbon 14 and the solid residue obtained after the first stage, mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

21. The method according to claim 9, in which the carbon-containing wastes initially contain carbon 14, and the solid residue obtained after the first stage, mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

22. The method according to item 12, in which the carbon-containing wastes initially sod is rat carbon 14, and a solid residue, obtained after the first stage, mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

23. The method according to 17, in which the carbon-containing wastes initially contain carbon 14, and the solid residue obtained after the first stage, mainly contains carbon 14, while the carbon monoxide obtained after the second stage contains carbon 14 in the residual amount.

24. The method according to one of claims 1 to-4, 6, 8, 10, 11, 13-16 and 19 to 23, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

25. The method according to claim 5, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

26. The method according to claim 7, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

27. The method according to claim 9, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

28. The method according to item 12, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

29. The method according to 17, characterized in that the said carbon-containing wastes contain at least graphite and/or resin.

30. The method according to p, characterized in that the said carbon-containing wastes contain m is Nisha as graphite and/or resin.

31. Installation for processing carbon-containing radioactive waste, characterized in that it contains means for implementing the method according to one of the preceding paragraphs.



 

Same patents:

FIELD: physics, nuclear.

SUBSTANCE: invention relates to nuclear power and particularly issues of handling liquid radioactive wastes. The method of cleaning still residues of liquid radioactive wastes from radioactive cobalt and caesium by oxidising the still residue and extracting activated corrosion products by filtering, characterised by that hydrogen peroxide is added to the still residue and repeatedly passed in circulation mode through a tubular reactor, while exposing the still residue to hard UV radiation; the process is carried out at solution pH 7-10 and temperature 45-98°C; after separating the sludge by microfiltration, said sludge containing radioactive cobalt, iron and manganese, solutions of diethyldithiocarbamates of alkali metals and transition metal salts are simultaneously added to the filtrate at the same pH and temperature values, followed by separation by microfiltration of the formed precipitate of diethyldithiocarbamates of transition metals with radioactive cobalt; and radioactive caesium is extracted on ion-selective sorbents in steps using a counterflow method with removal of spent sorbents by microfiltration together with cobalt diethyldithiocarbamate.

EFFECT: invention enables to avoid use of an ozonator station, makes the process safer and considerably increases efficiency of processing liquid radioactive wastes.

5 cl, 3 ex, 4 tbl

FIELD: power engineering.

SUBSTANCE: proposed method consists in thermal oxidative of irradiated fuel from uranium dioxide and comprises separating fuel elements into fragments, and oxidative treatment of said fragments by gas-air mix in two steps: first, by mix of air and carbon dioxide at 400-650°C, and, second, by steam-air mix at 350-450°C. Both steps are implemented at continuous or intermittent mechanical activation of reaction stock.

EFFECT: higher yield of tritium, reduced sublimation of cesium compounds.

3 cl, 1 ex

FIELD: power industry.

SUBSTANCE: treatment method of radioactive contaminated metal and graphite wastes of uranium-graphite nuclear reactors involves loading of radioactive contaminated metal wastes and flux to oven, melting of metal wastes, and removal of molten metal and formed slag flux from the oven. Before radioactive contaminated metal wastes are loaded to the oven there loaded is layer of radioactive contaminated graphite and it is ignited in oxidising medium with plasma generated by plasmatron of the oven; after that, plasmatron is switched off and loading of fragmented radioactive contaminated metal wastes and flux are loaded to the furnace downwards and layer by layer.

EFFECT: invention allows minimising the volume of secondary radioactive wastes, reducing energy consumption and excluding the possibility of occurrence of emergency situation.

1 dwg

FIELD: nuclear physics.

SUBSTANCE: invention relates to environmental protection, specifically to devices for treating highly active sources of ionising radiation by enclosing them in a metallic matrix directly in the storage, and can be used at centralised nuclear waste disposal points. The proposed device has an electrofusion device, a buffer chamber with a flexible metal conductor inside it. The electrofusion device is placed in the buffer chamber, the input of which is mated with the flexible metal conductor through a flange connection with a locking mechanism. The buffer chamber is fitted with an outlet pipe and is connected to a system for cleaning and pumping air, which consists of a filter and a ventilator. The flexible metal conductor is made in form of a spiral metal hose made from stainless steel with four heat insulating layers made from glass or basalt, or organosilicon fibre. Between the first and second heat insulating layers there is a thermal converter which is connected to an electrical circuit in the control console of the device, and between the second and the third layers there is a copper current conducting bus which is connected at the lower end of the flexible metal conductor with the spiral metal hose using a collar clamp. The upper end of the flexible metal conductor is mated with above mentioned flange connection with a locking mechanism.

EFFECT: proposed device prevents crystallisation of molten matrix material in the flexible metal conductor and breaking of the metal conductor in the loading channel of the storage.

1 cl, 2 dwg

FIELD: nuclear power production industry.

SUBSTANCE: radioactive ion-exchanging resins preparation for immobilisation into bulk structures. Radioactive ion-exchanging resin is mixed with hard non-organic inert bulk material. After that, during mixing the above mixture is exposed to thermal treatment at the temperature no less than 250°C but not higher than 300°C.

EFFECT: reduction of power consumption, prevention of radioactive ion-exchanging resins products agglomeration after thermal treatment, prevention of radioactive ion-exchanging resins inflammation risk during thermal treatment, prevention of volatile resin and oil compositions formation, simplification of process, increased compatibility of radioactive ion-exchanging resins with cement-like materials after their thermal treatment.

FIELD: nuclear power engineering.

SUBSTANCE: in process of chemical deactivation double-bath oxidising-reducing treatment of equipment surfaces is performed with aqueous solutions of chemical reagents in the mode of their forced mixing at preset temperature and time. In the first bath surfaces are treated with aqueous solution of potassium permanganate with acetic and nitric acids. At that initial PH value of solution makes from 1.0 to 2.5. Ratio of components is maintained within the limits from 1:9:1 to 1:1:9. On completion of oxidising treatment excessive potassium permanganate and deposits of manganese dioxide are destroyed with hydrogen peroxide. In the second bath treatment is performed with aqueous solution of oxyethylidenediphosphonic acid with hydrazine. Ratio of components makes 1.0:0.25. At that initial PH value of solution is not less than 3.5, solution pH is corrected with ammonia.

EFFECT: makes it possible to increase efficiency of deactivation, to reduce radiation doses on NPP service personnel, to reduce amount of produced liquid radioactive wastes.

3 cl, 4 tbl

FIELD: decontaminating methods.

SUBSTANCE: proposed method for decontaminating nuclear reactor circuit includes treatment of internal surfaces with oxalic acid solution at the same time cleaning decontaminating solution from corrosion products dissolved on ion-exchange filters filled with anionite in oxalate form. Oxalate-form anionite filters are periodically reconditioned using nitric acid solution.

EFFECT: reduced amount of decontamination process wastes.

2 cl, 2 dwg, 1 tbl

FIELD: recovery of radioactive, mainly metal and fuel, solid radioactive wastes in nuclear industry.

SUBSTANCE: solid radioactive metal and fuel wastes are treated in recirculating slag melt of furnace by passing them through two separate recirculating circuits. Radioactive fuel wastes are charged for recovery in the form of solid coke residue upon pyrolytic treatment. Furnace implementing this method has additional recirculating circuit wherein melting chamber is combined with preheat and settling chambers and communicates with gas-lift chamber through L-shaped heat-generating channel. In this way two different kinds of wastes are recovered at a time in single unit.

EFFECT: enhanced specific productivity, reduced power requirement for recovering radioactive wastes.

2 cl, 1 dwg

FIELD: decontaminating solid iodine filters used in nuclear industry.

SUBSTANCE: proposed method includes bringing filters in contact with aqueous solution of reducing agent chosen from hydroxylamine, hydroxylamine salts, ascorbic acid, ascorbic acid salts, mixed ascorbic acid anhydrides, sodium boron hydride, sodium hypophosphate, formaldehyde, urea, formic acid, and their mixtures so as to extract iodine from filter and to dissolve it in aqueous solution. Silver can be also dissolved at the same time or sequentially in reducing agent or in any other suitable aqueous solution.

EFFECT: enhanced degree of decontamination, facilitated procedure using aqueous solution and simple vat.

13 cl

FIELD: environment control.

SUBSTANCE: dry or wet, granulated, powdered, or milled spent ion-exchange resins are included in matrix in N- or H-form. Used as matrix base is mixture of blast-furnace slag milled to fraction of 0.075 mm and chrysotile-asbestos in the amount of 5 mass percent. Sodium hydroxide solution is added to mixture in the amount of 100 -150 g/l.

EFFECT: enhanced degree of filling the compound and enhanced reliability of further storage.

1 cl, 1 dwg, 2 tbl, 8 ex

FIELD: handling spent nuclear fuel.

SUBSTANCE: proposed method includes disposition of spent fuel assembly in box and its exposure to dry heated inert gas environment. Drying process takes several cycles each time holding box space with fuel assembly under vacuum. Then box is filled with dry heated inert gas blown down for drying through adsorbers made in the form of shell-and-tube heat exchangers with sorbent-carrying tubes. Adsorbers are regenerated. In the process steam is blown through adsorber space and upon termination of desorption cooling water is passed through this space. Tube space of adsorbers is connected to vacuum line isolated from that of case. Upon sorbent cooling tube space is blown down with dry inert gas supplied from adsorbers drying out fuel assemblies while case space is held under vacuum.

EFFECT: reduced drying time, enhanced drying quality and safety.

2 cl, 1 dwg

FIELD: reprocessing of worked-out equipment, contaminated with radioactive impurities.

SUBSTANCE: claimed method includes deactivation of contaminated equipment in assembly, disassembling, fragmentation, separation of surface-contaminated fragments, deactivation thereof, classification of metal kinds and groups, and acceptance of mechanical and physical alterations. Fragments satisfied to acceptance results are deactivated without changing form and metal structure thereof and separated into fragments for direct application and for technological update. Fragments not satisfied to acceptance results are used as debris of metal radwastes in metallurgy to produce steel and alloys. Method for production of steel and alloys includes batch preparing, additive introducing during melting process and casting of finished metal. Necessary debris amount to produce desired chemical element content in specific grade of steel or alloy is predetermined followed by calculation of dilution coefficient and upper limit value of debris specific activity. Then debris with specific activity of not more than calculated upper limit value is fed in founding as the base metal and/or addition alloy.

EFFECT: simplified and economy reprocessing method; increased metal amount recycled into national economy, and reduced solid radwaste amount.

3 cl, 2 ex

FIELD: recovery of biologically hazardous wastes.

SUBSTANCE: proposed method includes introduction of toxic and radioactive material neutralization wastes into reactor together with charge, heating them with aid of superhigh-frequency energy, and hardening; toxic material neutralization wastes are decomposed in the course of heating. Reactor charge composed of river sand and cullet doped with boron acid and red lead in 5 : 1 proportion is used for hardening wastes by vitrification.

EFFECT: enhanced quality of waste recovery.

1 cl, 1 dwg, 1 tbl

FIELD: nuclear engineering; methods of processing of radioactive waste.

SUBSTANCE: the invention is pertaining to the field of processing of radioactive waste. The method of melt-shutting of dangerous materials and-or products provides for arrangement of the melt-shutting material, the subjected to the melt-shutting dangerous materials and-or products in a metal container and their heating by UHF-energy. In the capacity of the melt-shutting material use a loose radio-transparent material, in which dip the subjected to the melt-shutting dangerous materials and-or products till their complete surrounding by the radio-transparent loose material. Then using UHF-energy heat up the subjected to the melt-shutting dangerous materials and-or products, at least, to the melting point of the loose radio-transparent material contacting with the subjected to the melt-shutting dangerous materials and-or products for formation around the subjected to the melt-shutting dangerous materials and-or products of a monolithic shell. The technical result of the invention is a reliable fixation of the hazardous substances.

EFFECT: the invention ensures a reliable fixation of the hazardous substances.

3 cl, 4 dwg

FIELD: nuclear engineering; methods of processing of the solid radioactive waste.

SUBSTANCE: the invention is pertaining to the field of nuclear engineering, to the methods of processing of the solid radioactive waste, in particular, to the methods of processing of the metallic waste containing radionuclides. The method of processing of the metallic waste containing radionuclides includes the waste smelting and the metal casting. At that the processing includes in two phases. At the first phase the waste is subjected to a thermal decontamination in the open air at the temperature of 450 - 700°C. At the second phase conduct the waste smelting under vacuum at a heating rate of 300 - 450°C per hour, then the melt is aged for 10-20 minutes and cast in a mold. The invention ensures reduction of contamination of the gained metal.

EFFECT: the invention ensures reduction of contamination of the gained metal.

1 tbl, 1 ex

FIELD: nuclear engineering.

SUBSTANCE: proposed method includes mixing of heavy-metal fluorides with reducer free from hydrogen atoms and fluoride-binding component. This is followed by heat treatment, and aerosols produced in the process are cooled down followed by their separation into solid and gaseous fractions. Reducer incorporates fluoride-binding component in the form of carbon, sulfur, volatile metals, and their acid-containing components.

EFFECT: facilitated procedure and enhanced effectiveness of process.

1 cl, 1 dwg, 1 ex

FIELD: environment control.

SUBSTANCE: dry or wet, granulated, powdered, or milled spent ion-exchange resins are included in matrix in N- or H-form. Used as matrix base is mixture of blast-furnace slag milled to fraction of 0.075 mm and chrysotile-asbestos in the amount of 5 mass percent. Sodium hydroxide solution is added to mixture in the amount of 100 -150 g/l.

EFFECT: enhanced degree of filling the compound and enhanced reliability of further storage.

1 cl, 1 dwg, 2 tbl, 8 ex

FIELD: decontaminating solid iodine filters used in nuclear industry.

SUBSTANCE: proposed method includes bringing filters in contact with aqueous solution of reducing agent chosen from hydroxylamine, hydroxylamine salts, ascorbic acid, ascorbic acid salts, mixed ascorbic acid anhydrides, sodium boron hydride, sodium hypophosphate, formaldehyde, urea, formic acid, and their mixtures so as to extract iodine from filter and to dissolve it in aqueous solution. Silver can be also dissolved at the same time or sequentially in reducing agent or in any other suitable aqueous solution.

EFFECT: enhanced degree of decontamination, facilitated procedure using aqueous solution and simple vat.

13 cl

FIELD: recovery of radioactive, mainly metal and fuel, solid radioactive wastes in nuclear industry.

SUBSTANCE: solid radioactive metal and fuel wastes are treated in recirculating slag melt of furnace by passing them through two separate recirculating circuits. Radioactive fuel wastes are charged for recovery in the form of solid coke residue upon pyrolytic treatment. Furnace implementing this method has additional recirculating circuit wherein melting chamber is combined with preheat and settling chambers and communicates with gas-lift chamber through L-shaped heat-generating channel. In this way two different kinds of wastes are recovered at a time in single unit.

EFFECT: enhanced specific productivity, reduced power requirement for recovering radioactive wastes.

2 cl, 1 dwg

FIELD: decontaminating methods.

SUBSTANCE: proposed method for decontaminating nuclear reactor circuit includes treatment of internal surfaces with oxalic acid solution at the same time cleaning decontaminating solution from corrosion products dissolved on ion-exchange filters filled with anionite in oxalate form. Oxalate-form anionite filters are periodically reconditioned using nitric acid solution.

EFFECT: reduced amount of decontamination process wastes.

2 cl, 2 dwg, 1 tbl

Up!