Method of cleaning still residues of liquid radioactive wastes from radioactive cobalt and caesium

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

 

The invention relates to the field of nuclear energy, applies, in particular, the treatment of liquid radioactive waste (LRW) and can be used in the processing of bottoms (KO) evaporators installations recycling drain water nuclear power plants (NPP).

LRW treatment NPP is one of the most urgent tasks in the field of processing and storage of radioactive waste. During the operation of nuclear power plants produce large amounts of liquid radioactive media: organized leakage (drain water), spent decontamination solutions, water, Laundry, water rooms, regeneration solutions ion exchange filter systems specutacular, etc. that are collected are averaged and concentrated by evaporation. LRW homogeneous composition NPP contaminated with fission products, mainly134,137Cs and activated corrosion products, mainly60With. In small quantities, there are more short-lived radionuclides manganese, iron, chromium, copper, zinc. Formed during the process of evaporation distillation residues are sent to temporary storage in concrete lined tanks. When storing hard-soluble compounds, including parts of radionuclides, precipitates and is collected at the bottom in the form of sludge and a clarified portion TO gradually Dec is ntinued and processed. For processing and conditioning TO use different methods: bitumirovannaya, cementing, calcification, getting salt water, with the placement of the cured product in drums or concrete containers. Immobilization of salts and radionuclides from VAT residue in the solid matrix and placing it in the container, obtaining packaging hardened LRW, is the main method of processing TO the NPP. This leads to the formation of a large amount of radioactive product and requires significant material costs as to receive packages hardened LRW, and their subsequent long-term storage in the storage of solid radioactive waste (HTR).

In this regard, were the development direction of the processing TO by the allocation of these radionuclides in a small volume of sludge and ion-selective sorbents and receiving non-radioactive or ' low-level ' salts that are related to the category of ono (sobeyscorporate waste), which is possible on the landfill of industrial waste or in simple sheds. Radioactive substances in solutions of the cubic residue LRW are in the form of simple and complex ions and colloidal particles. The main radionuclides are137Cs134Cs60Co. Isotopes of cesium are in solution in ionic form. Isotope60Co - forma complexes with compounds used for decontamination of equipment, such as oxalic acid, polyphosphates and other Therefore, for the selection of this radionuclide from solution it is necessary to destroy these complexes.

There is a method of destroying organic complexes60With ozonation (RF patent No. 2268513). The process is carried out at a pH value of 12 to 13.5. The resulting radioactive sludge consisting mainly of iron hydroxide and transition metals, which contains the main part of the60With, separated by filtration. The filtrate, in the future, we isotopes of cesium, passing through the filter with ion-selective for cesium inorganic sorbent.

The disadvantage of ozone are: low efficiency of selection in a slurry of activated corrosion products caused by the inability of ozone to destroy the oxalate of transition metals and polyphosphate complexes; the danger of using ozone as it relates to potent substances and its concentration in the air should not exceed 0.1 mg/m3and high cost due to the high consumption of reagent (10 kg ozone per 1 m3VAT residue) and electricity.

The closest analogue of the claimed invention is a method proposed in international patent WO/2007/123436, where instead of ozone are encouraged to use other oxygen-containing the oxidizing agents: for example hydrogen peroxide, the potassium permanganate, sodium persulfate or ammonium in the form of solutions, as well as oxygen. In this patent is carried out initially purified from cesium before decomposition of organic complexes of cobalt. Indicate that the oxidation process need TO be carried out at elevated temperature and pressure above the saturated vapor pressure of the liquid for this temperature. Is an example of a cleaning VAT residue using 30% hydrogen peroxide as oxidant. The essence of this process lies in the fact that the VAT residue of liquid radioactive waste are oxidized, and then remove the activated corrosion products by filtration. At the process temperature of 200°C and a pressure of 6 MPa radioactivity in60Was reduced to 160 Bq/L.

This method is complicated and not efficient enough, as you need to maintain high temperature and high pressure. Under such hard conditions of the process a significant portion of activated corrosion products deposited on the walls of the equipment, and not on the sludge, which could be separated by filtration. The deposition of radionuclides on the walls of the equipment to withdraw can only be washing decontamination solutions with translation again in the dissolved state, i.e. to return to its original position, which significantly reduces the effectiveness% of the SAR.

The problem solved by the invention is to simplify and increase the efficiency of the method of deducing from VAT residue of activated corrosion products without conducting hazardous processes (getting oxygen and ozone) and the use of high pressures and temperatures, use of toxic reagents (ozone).

The invention consists in that in the method of cleaning bottoms liquid radioactive waste from radioactive cobalt and cesium by oxidation of VAT residue and allocation of activated corrosion products filtering proposed in the VAT residue to dispense hydrogen peroxide and miss him repeatedly in the circulation through the tubular reactor, affecting VAT residue hard ultraviolet radiation, a process carried out when the value of pH 7 to 10 and a temperature of 45 to 98°C, after separation by filtration of the sludge containing radioactive cobalt, iron, manganese in the filtrate at the same time to impose solutions diethyldithiocarbamate alkali metal and transition metal salts with the same pH and temperature, followed by separation by filtration of the resulting precipitate diethyldithiocarbamate transition metals with radioactive cobalt and radioactive cesium output to the ion-selective sorbents speed countercurrent method removed the eating of spent sorbents by microfiltration together with cobalt diethyldithiocarbamate. In addition, the proposed VAT residue to act hard ultraviolet radiation with continuous injectioni air in the reactor, hard UV exposure conducted using a xenon lamp as a transition metal salts to use salts of manganese and cobalt, the imposition of solutions diethyldithiocarbamate alkali metals and salts of transition metals precipitation and separation by microfiltration to implement from 1 to 3 times.

The novelty of the process lies in the fact that oxidative processing VAT residue with the introduction of hydrogen peroxide, injectionem and exposure to harsh ultraviolet (UV) radiation destroys organic complex compounds, including oxalates, and the subsequent step coprecipitation of trace components with diethyldithiocarbamate manganese and cobalt allows you to remove the activated corrosion products to the required values. This leads to the reduction of the volume of radioactive waste by deep LRW treatment of high TDS from radionuclide60With and highlight it in a compact form in the sludge and membrane not easily soluble compounds, obtaining granulated salts of VAT residue (related to the category of particularly low level waste), and the subsequent purification of the solution by the method of ion-selective sorption from for the nuclides 134,137Cs, evaporation of the solution, granulation and drying ballast salts.

Using the technology developed in the first stage bottoms distillation residue is subjected to oxidation in the circulation in a closed circuit: the capacity→pump→UV reactor→capacity, at a temperature of 45-98°C, UV light, xenon bulbs. In addition, conduct dosed introduction of hydrogen peroxide, the injection box compressed air and oxygen-enriched air from the tank. After the oxidation processing portion TO the circulation, remove sludge formed by microfiltration on a curtain filter with the introduction of the flocculant and then the two-stage processing with the addition of sodium diethyldithiocarbamate (DDTC-Na), salts of manganese and cobalt followed by microfiltration on a curtain filters. The formed amount of the thickened pulp at this stage is 1.5-2% of the volume TO. The result of this operation removes the activated corrosion products. Next TO is purified from radionuclides of cesium by stepwise countercurrent adsorption on Nickel ferrocyanide, enter in the amount TO. You can also use powdered ion-selective sorbents. Remove ferrocyanides with radionuclides cesium occurs at the last stage of processing VAT residue by cobalt diethyldithiocarbamate. The thickened pulp is slurries are invited to serve in the capacity of reception and temporary storage of spent of filtering materials for their subsequent joint cementing, either directly in an intermediate tank for the installation of cementing LRW heterogeneous composition, and dry granular salt in bags put in storage in the storage hangar type, or subsequent, in the construction of the industrial waste, put in storage as chemical waste.

The prior art process of water splitting under the action of hard ultraviolet radiation on the HE·radical and N·- radical. HE·radical is one of the strongest oxidizing agents. However, the zone of action of UV radiation in water is limited, which significantly reduces the yield of the reaction for the decomposition of water, and, in addition, this should cause unwanted release of hydrogen. The introduction of the hydrogen peroxide solution was allowed to implement the process of the decomposition of H2O2at two HE·radical, which is much easier and without hydrogen evolution. Introduction into the aquatic environment of the injected air bubbles increases the range of ultraviolet radiation and increases the yield of the reaction photolysis of hydrogen peroxide, which, in turn, increases the reaction rate of oxidation of organic complexes. From techniques known to use diethyldithiocarbamate transition metals for conducting quantitative photocolorimetric set the deposits. However, this is only used color solutions diethyldithiocarbamate transition metals. It is also known the use of compounds of diethyldithiocarbamate transition metals for separation of metals by the method of paper chromatography. The use of extraction diethyldithiocarbamate complex chloroform formed the basis for the quantitative determination of ions in water manganese, zinc, cobalt. However, in the developed method uses the ability diethyldithiocarbamate complexes of transition metals in certain pH values to form poorly soluble compounds and choosedate with them activated corrosion products. Obviously the strength diethyldithiocarbamate complex compounds of cobalt is higher than the strength of indestructible oxidation polyphosphate complex compounds of cobalt, which helps speed the excretion60With to the appropriate value.

Specific example 1.

VAT residue LRW subjected to the preliminary adjustment of the pH to 8, dosed introduction of concentrated nitric acid (concentration of technical HNO354÷57%). Then the solution was heated to 98°C, was injected 30% solution of hydrogen peroxide in the amount of 15% of the volume TO. Within 6 hours provided the circulation VAT residue through a UV reactor with UV xenon is howling lamp. During the first three hours was carried out even additional supply of hydrogen peroxide in the amount of 15% of the volume TO. To improve the mixing and increase the rate of oxidation in circulating TO have injectively compressed air. After oxidation, the solution was cooled to 45°C, was introduced flocculant and loose the solid phase was separated by filtration on a curtain membrane filter. Then the filtered solution was again heated to 75°C., is injected with a solution of manganese nitrate and sodium diethyldithiocarbamate in the rate of 6 g and 10 g of salt per liter of processed solution, respectively, and kept under stirring for 2 hours. Precipitated solid phase of diethyldithiocarbamate manganese was separated by filtration on a curtain filter.

In the second stage coprecipitation solution was again heated up to 75°C, was injected solutions of cobalt nitrate and sodium diethyldithiocarbamate in quantities based on 6 g and 10 g of salt per liter of solution, respectively, and kept under stirring for 2 hours. Precipitated solid phase of diethyldithiocarbamate manganese was separated by filtration on a curtain filter.

After filtration the solution was added nitrate Nickel (II) and potassium ferrocyanide for the removal of caesium isotopes.

Treatment result was the decrease in activity of the cubic residue:

- 60With with 5.6·104the K/DM 3to 2.70·102Bq/DM3;

- 137Cs-2.6·106Bq/DM3to 2.9·103Bq/DM3.

Specific example 2.

The oxidation was carried out similarly to example 1.

During coprecipitation on each of the two stages of oxidation used cobalt nitrate and sodium diethyldithiocarbamate in quantities of 6 g and 10 g per 1 liter of the solution, respectively.

The cesium was removed from the solution as in example 1.

The result of this selection was the decrease in activity of the cubic residue:

- 60With with 5.6·104Bq/DM3to 1.2·102Bq/DM3:

- 137Cs-2.6·106Bq/DM3up to 5·102Bq/DM3.

Specific example 3.

The oxidation and precipitation of the first stage was carried out similarly to example 1.

At the second stage coprecipitation, together with the addition of cobalt nitrate and sodium diethyldithiocarbamate introduced a suspension formed by mixing solutions of ferrocyanide of potassium and Nickel nitrate. After 2 hours of co-precipitation at 75°C., filtering the precipitate was achieved degree of purification similar to that of Example 1.

The final activity of the cubic residue:

- 60With=2,6· Bq/DM3;

- 137Cs=4·103Bq/DM3.

Which suggests the simultaneous purification of radionuclides of cobalt and cesium.

Other examples done by the means of the method presented in tables 1, 2, 3, 4, where: table 1 illustrates the effectiveness of the cleaning method TO at variable pH values, table 2 shows the effectiveness of the method depending on the temperature, table 3 illustrates a stage of the method according to step coprecipitation, table 4 illustrates the removal efficiency137Cs subsequent ion sorption on the ferrocyanide of Nacala-potassium.

The results of the examples of how specific performance show that coprecipitation with Co(DDTC)2more efficient than with Mn(DDTC)2. Cobalt salts are 2-3 times more expensive than similar salts of manganese. The use of salts of manganese or cobalt is determined by the specific requirements of efficiency and maintainability of the cleaning process. As can be seen from Fig.5 table 3 third stage coprecipitation also improves the removal of60With order and get its residual content in the solution for 15 Bq/DM3.

The proposed method has the following advantages over the ozonation:

Avoids the use of ozone station and make the process more secure. Significantly improve the performance of processing waste. The process of preparation of reagent solutions-coosawatee and their interaction TO occur faster than the generation of the necessary amount of ozone and ozonation VAT residue. The advantage soo is ardenia is less power consumption and increase the efficiency of removal of VAT residue of activated corrosion products.

1. The method of cleaning bottoms liquid radioactive waste from radioactive cobalt and cesium by oxidation of VAT residue and allocation of activated corrosion products by filtration, characterized in that the VAT residue dispense hydrogen peroxide and let it multiply in circulation through the tubular reactor, affecting VAT residue hard ultraviolet radiation, the process is conducted at a value of pH 7÷10 and a temperature of 45÷98°C, after separation by filtration of the sludge containing radioactive cobalt, iron, manganese in the filtrate at the same time introducing solutions diethyldithiocarbamate alkali metal and transition metal salts with the same pH values and temperature, followed by separation by filtration of the resulting precipitate diethyldithiocarbamate transition metals with radioactive cobalt and radioactive cesium display on ion-selective sorbents speed counter-current method with the removal of the spent sorbents by microfiltration together with cobalt diethyldithiocarbamate.

2. The method according to claim 1, characterized in that the VAT residue effect hard ultraviolet radiation with continuous injectioni otdyha in the reactor.

3. The method according to claim 1 or 2, characterized in that the hard ultraviolet exposure is performed using a xenon lamp.

4. The method according to claim 1, characterized in that salts of transition metals use salts of manganese and cobalt.

5. The method according to claim 1 or 2, characterized in that the infusion of diethyldithiocarbamate alkali metals and salts of transition metals precipitation and separation by microfiltration carry from 1 to 3 times.



 

Same patents:

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: 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: 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!