Cleaning method kaboolian solutions type sea water from radionuclides and installation for its implementation

 

(57) Abstract:

The invention relates to chemical technology, specifically for nuclear ecology and can be used in the processing of liquid radioactive waste (LRW) generated by the operation of the various nuclear power plants (NPP) on vehicles (atomic icebreakers, submarines, floating NPP). The essence of the invention lies in the fact that Laboulaye solutions type sea water clear of radionuclides by contact with an inorganic sorbent on the basis of ferrocyanide transition metal (copper or Nickel) and a porous inorganic carrier, which is used as the sorbent grade NGA or MJA-M, followed by the introduction of chemical precipitating the sulfate ions, which is used as the chloride of barium, its molar ratio to the sulfate ion, equal to (1,0-1,1):1, separating the precipitate and storage over time, 8-10 half-life dedicated separated from the sediment radionuclide, preferably within 1200-1600 day. To implement the method proposed installation for cleaning kaboolian solutions type sea water from radionuclides containing sequentially raspevnye dispensers to enter a chemical reagent, sumps and storage tanks for radioactive sludge, made multiple, preferably in quantities of 4-6 sections, whereby each section may be a number of steel or plastic drums with a volume of 200 l each. 2 s and 5 C.p. f-crystals, 1 tab., 1 Il.

The invention relates to chemical technology, specifically for nuclear ecology and can be used in the processing of liquid radioactive waste (LRW) generated by the operation of the various nuclear power plants (NPP) on vehicles (atomic icebreakers, submarines, floating NPP).

In the process of nuclear energy cycle form different types of LRW, which must then be processed with a view to their subsequent disposal in the compact solid form.

In some cases, when the transport operation of the NPP are "non-standard" LRW, chemical and radionuclide compositions which differ significantly from normal. So, when the decommissioning of nuclear powered submarines (NPS) are formed salt LRW, representing sea water with salinity 20-23 g/l, in which the main radionuclide is an isotope of sulfur-35 (half-life of 80 days) ACD/SUP> CI/l) [1] Such solutions at the disposal of one of the submarines is formed about 300 cubic meters

Some of these solutions may also contain long-lived radionuclides cesium-137 and strontium-90 at the level of 2-5 MPC. Traditional deposition methods may not provide the required sanitary standards SPORO-85 for cleaning such salt solutions [2]

Closest to the described method of cleaning kaboolian solutions type sea water from radionuclides is a method involving the introduction of a chemical sedimentary sulfate ions, separating the precipitate and storage [3] Cleanup of lead content in purified solution of radionuclides of cesium and strontium < 1x10-9Ku/l

According to the method of salt LRW sequentially subjected to the following stages of processing. First, the solutions are sent to the stage of deposition, which is carried out for the removal of short-lived radionuclides. Removal of sulfur found in seawater in the form of sulfate ions, using a water-soluble barium salt such as barium chloride. Barium sulfate has a very low solubility in a wide range of pH, and adding stoichiometric amounts of ions of barium sulfate ions are almost completely ocidate in a salt solution of 2.2-2.4 g/l of barium chloride.

Then, to achieve a desired degree of cleaning solutions from all radionuclides are adjusting pH, add special complexing agents, such as dicarbonyl cobalt, which binds to the solid complexes cesium ions, and then carry out the separation of the formed complex organic reagents. These operations are very difficult, time consuming and lead to the formation of a large number of secondary radioactive waste.

The disadvantage of this method is the low degree of concentration of radionuclides in the solid phase, which is one of the main economic indicators of the whole process. According to the method of processing, it does not exceed 50.

Closest to the proposed installation is to install to clean kaboolian solutions type sea water from radionuclides containing sequentially arranged and interconnected reinforcement products receiving tanks: tanks for sedimentation, which are equipped with dispensers to enter the chemical reagent reservoirs, sumps and storage tanks for radioactive sludge [3]

In this installation, perform the purification processes of radioactive solutions precipitation monnich containers. For disposal taking into account the presence of caesium radionuclides requires special protective containers. This leads to an increase 3-5 times the total number of buried TRO, which is a disadvantage of the known installation.

The objective of the invention is to develop a method and installation, allowing to achieve a high degree of concentration of radionuclides utilized in the final product solid waste, and therefore to decrease the number of disposed solid waste.

The task is achieved by the described method of cleaning kaboolian solutions type sea water from radionuclides, including their contacts with inorganic sorbent-based transition metal ferrocyanide and the subsequent introduction of a chemical reagent, precipitating the sulfate ions, the separation of radioactive sludge and storage over time, 8-10 half-life dedicated separated from the sediment radionuclides.

The inorganic sorbent preferably used sorbent on the basis of ferrocyanide of copper or Nickel and a porous inorganic carrier grade NGA or MJA-M, and as a chemical reagent to precipitate the chlorine which is before the introduction of chemical precipitating the sulfate ion, laboravi solution type sea water in contact with inorganic sorbent-based transition metal ferrocyanide, and storage of sediment are in a period of time equal to 8-10 half-life dedicated separated from the sediment radionuclides.

Other differences of the method lies in the fact that as a chemical reagent use barium chloride when its molar ratio to the sulfate ion, equal to (1,0-1,1): 1, and as the inorganic sorbent-based transition metal ferrocyanides sorbent on the basis of ferrocyanide of copper or Nickel and a porous inorganic carrier grade NGA or MJA-M

Another difference is that in the absence of kaboolian solutions type sea water radionuclides strontium deposited sediment are within 1200-1600 day.

The problem is solved also described a system for cleaning kaboolian solutions type sea water from radionuclides containing sequentially arranged and interconnected receiver tanks, block sorption, capacity for deposition with dispensers for input of chemical reagent barb for the storage of radioactive sludge contain 4-6 sections, each of the sections can be a number of steel or plastic drums with a volume of 200 liters

The hallmark of the installation is that it further comprises a sorption unit, an input connected to receiver tanks, and output containers for deposition and storage tanks for radioactive sludge made multiple.

Still some differences in installation are that storage tanks for radioactive sludge contain preferably 4-6 sections, and each section can represent a number of steel or plastic drums with a volume of 200 l each.

The proposed installation, the scheme of which is shown in the drawing, consists of the following main components: 1 receiver tanks (there are two pieces to separate acceptance of solutions containing radionuclides of sulfur and also along with them radionuclides of strontium, 2 sorption unit 3 capacity for deposition, 4 the dosing pump to enter the reagent barium chloride, 5 tank storage tank 6 tank-chemoablation, 7 storage tanks for sludge.

The device operates as follows. Based on Laboulaye solutions type sea water with a salinity of about 20 g/l podutil sorbent.

The sorption unit can be a conventional column pressure type, placed in a protective container. In another embodiment, it is a device which includes, in addition convoy protection and removable inner shell with the sorbent. This option allows the replacement of the sorbent after developing a resource together with sorption shell, which in turn provides the required norms of radiation safety (SPORO-85) conditions of work of the staff of spent sorbent, excluding dangerous operation overload.

Before disposal of sorbent is carried out drainage sorbent directly into the sorption cowling by means of its connection to a vacuum pump or blowing hot nitrogen. The operation for the disposal of the sorbent is carried out using a special mechanical device, which pulls the shell together with the active sorbent is transported inside the protective container. After that, the shell is transported for disposal in special reinforced concrete protective container.

Through the sorption unit flow solutions with a speed of 10-20 K. O./h (volume of solution equal to the volume of sorbent). In this mode through one Ohm by the way, through one liter of sorbent miss 30 cubic meters of solution.

When the content in the source solution 10-8CI/l cesium-137 final content filters will be at the level of 10-10CI/l, which corresponds to sbresny standards in the environment, and its content in the sorbent will be (2-3) X10-4CI/l, which allows to re-use it when cleaning more "contaminated" by the radionuclide cesium solutions.

If present in the original solution of trace amounts of cobalt-60 he also absorbed by 50-60% sorbent, which is sufficient to obtain a discharge standards.

Then the filters come in containers for deposition 3, equipped with dosing pumps 4 to enter a chemical precipitant from the tank 5. For this process using conventional chemical tanks precipitators with conical bottoms with the top fence dicontinuing solution. To prevent contact with decantation fine sediment on the line issuing put a mechanical filter. The precipitation are concentrated (120-150 g/l) solution of barium chloride, dosing it in the stoichiometric ratio for the reaction

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Given the content of sulfate ions (about 1.5 g/l) is added 2,2-2,4 g/l of barium chloride, supporting mo is giving 15-20 min is the main precipitation of barium sulphate. After 14 h full quantitative precipitation.

After settling and decanting the solution from the tank 3 and tank 6 radionuclide content of sulphur-35 can be reduced in 70-100 times. At the same time by deposition from solution by coprecipitation removed isotopes of iron-55 and strontium-90 that may be present in trace. As a result, the filtrate is fully consistent with the required sanitary standards for discharge into open waters.

The precipitate after decanting the solution is discharged, separated from residual moisture content (before latest content of 40-60 wt.) and sent to conventional chemical tank 7 for storing. In quantitative terms, 1 m3purified solutions produces about 7 kg (15 l) sludge with a moisture content of about 50% (or about 3.5 kg, calculated on dry weight). This residue is subjected to radiometric analysis to determine the exact content of radionuclides. For the convenience of disposing of the installation is equipped with a 4-6 tanks, each of which is designed to store generated during the year of sediment.

Due to the fact that the limiting isotope in the sediment will be sulfur-35, which has a half-life of 80 days, then after about 1200 Orio conventional chemical waste. After four years this product be disposed of as ordinary chemical waste, and vacant the container load another portion of the sediment. In the case of cleaning solutions containing long-lived radionuclides of strontium in amounts greater than 10-9Ku/l, the sediment may not be treated as a normal chemical waste and must dispose of as radioactive product.

Example 1. In the installation shown in the drawing, conduct cleanup kaboolian solutions type sea water (tanks biological protection-CBS) with a salinity of 20 g/l and the content of ions, chlorides 55; sulfates 7,7; bicarbonate of 0.4; phosphates 0,07; bromine ion 0,02; sodium 30,6; magnesium 3,7; calcium 1,2; potassium 1,1.

In the solution containing the isotope sulfur-35 in number h-7CI/l and the isotope cesium-137 in the amount of 10-8Ku/L. cleaning solutions performed in the following sequence.

The original sea water solutions containing trace amounts of radioactive cesium and sulfur-35 is passed through the sorption unit with removable inner shell, which is ferrocyanide sorbent grade NGA. Through the sorption unit flow solutions with a speed of 10-20 K. O./h (amount is the degree of purification of the starting solution from radionuclides cesium is with 99% Then filters come in sizes 3 to precipitate, equipped with dosing pumps 4 to enter a chemical precipitant. Given the content of sulfate ions (about 1.5 g/l) added 2.2 g/l of barium chloride. Model the ratio of sulfate and barium 1:1. The deposition is conducted without adjusting the pH of sea water at pH 8,35. Within 15-20 min is the main precipitation of barium sulphate. After 14 h full quantitative precipitation.

After settling and decanting the solution of the radionuclide content of sulphur-35 can be reduced by 70 times, and the solution is fully consistent sbresny standards in accordance with SPORO-85 for discharge into open waters.

The precipitate after decanting the solution is discharged, separated from residual moisture content before the content of the last 49-60 wt. and sent to the usual four to six sectors of the chemical tank 7 for storing. In quantitative terms, 1 m3purified solutions produces about 7 kg (15 l) sludge with a moisture content of about 50% (or about 3.5 kg, calculated on dry weight).

Approximately 1200 sut sediment due to the natural decay of radionuclides sulfur-35 will be in the category of ordinary chemical waste. So after 1200 days this product is subjected in the SS="ptx2">

Example 2. Conduct cleanup operations as in example 1 except that in the original solution add strontium-85 in the amount of 1x10-9Ku/l, and as the inorganic sorbent used sorbent grade MJA) This sorbent has a resolution in the practice of purification of food products, and the solutions it can be discharged into surface waters without additional cleanup operations. The equilibrium content of copper ions in salt solutions after contact with the sorbent is < 0.03 mg/l

Through one volume of MJA-M miss 30 000 K. O. source solution with a speed of 10 K. O./h, while receiving the degree of purification from radionuclides of cesium, equal to 98.5%

The deposition of lead in example 1 except that the solution was added to 2.42 g/l of barium chloride (molar ratio of sulfate to barium is 1: 1,1). These conditions result in the precipitation of sulfate ions on 99% of the achieved result is purification from sulfur-35, equal to 100. When this is achieved the degree of co-precipitation of radionuclides of strontium, equal to 70%, and its content in the filtrate is reduced to 3 x 10-10Ku/L. After the deposition of radionuclides sulfur in the solution to remove excess barium ions add a solution culicinae the content of barium ions in the purified solution was 1.4 mg/l at its MPC 4 mg/L. Formed in this process, the precipitate of barium sulphate stored in special containers, representing plastic drums 200 l volume, and the storage process takes place as in example 1. Barrels filled with sediment during the first year after 3-5 years will be disposed of as ordinary chemical waste.

Example 3. Spend cleaning solution CBS in example 1 except that in the initial solution contains the isotope sulfur-35 in number 1,5x10-6Ku/l In the first stage, when sorption cleaning use a sorbent, MJA) the Equilibrium content of copper ions in salt solutions after contact with the sorbent is < 0.03 mg/l

Through one volume of MJA-M miss rate of 20 K. O./h 40 000 K. O. initial solution, while receiving the degree of purification from radionuclides of cesium, equal to 98%

In the second stage, carry out the precipitation of barium sulfate by introducing different amounts of ions of barium as barium chloride and determine the degree of deposition.

The degree of deposition of sulfate ions ,% of solution CBS the number of precipitator VA ions listed in the table.

As can be seen from the table, it is optimal to conduct a deposition when the molar ratio is to be placed sulfate ion, and hence the degree of purification from sulfur-35, which is sufficient to achieve acceptable concentrations of this isotope for discharge of treated water directly back into the sea.

If the initial solution isotopes of sulphur-35 and cesium-137 formed precipitate will contain only short-lived isotopes of sulfur-35. Its specific activity (S-35) will change over time as follows, Ku/kg: initial 2,710-4; after a year 1,510-5; after two years 9,010-7; after 3 years 5,110-8; after 5 years 1,710-10. Thus, in three to five years the sediment due to natural decay of sulfur-35 will move into the non-radioactive, and can be disposed of as ordinary chemical waste.

If the initial solution in addition to these isotopes radionuclides strontium in amounts greater than 10-9CI/l, part of the resulting sludge can be classified as radioactive. In practice, such solutions is formed not more than 2-3% of the total. In this case, the total degree of concentration of radionuclides in the solid phase, resulting in the described way will be the minimum possible and will be determined by the amount of the precipitated barium sulfate. This number when pererabotki is euclides, equal to 310. As seen from the above examples, in comparison with the prototype, where the degree of concentration of radionuclides in the solid phase, about 50, in the described method using the described device is achieved the degree of concentration at least equal to 310, which is 6 times more than in the prototype. When processing 98% of the total volume of the resulting solutions containing only radionuclides of sulphur-35 and cesium-137, the degree of concentration of radionuclides in the solid phase will amount to more than 30 thousand and Therefore the amount of recyclable solid radwaste in this way will end up in tens of thousands of times smaller than the prototype method.

After operations sorption, precipitation and settling the filtrate, representing the chemical composition of sea water, fully comply with regulatory requirements on the content of harmful chemicals, including radionuclide impurities, for discharge into the environment.

1. Cleaning method kaboolian solutions type sea water from radionuclides, including the introduction of a chemical reagent, precipitating the sulfate ions, the separation of radioactive sludge and storage, characterized in that before the introduction of chemical reagent restart over time, equal to 8 to 10 half-lives allocated to the separated precipitate of radionuclides.

2. The method according to p. 1, characterized in that as a chemical reagent for precipitation using barium chloride at a molar ratio of barium and sulphate ions 1,0 1,1 1,0.

3. The method according to p. 1, wherein as the inorganic sorbent used sorbent-based transition metal ferrocyanides copper or Nickel and a porous inorganic carrier grade NGA or MJA-M

4. The method according to p. 1, characterized in that in the absence of kaboolian solutions type sea water radionuclides strontium deposited sediment are within 1200 1600 day.

5. Installation for cleaning kaboolian solutions type sea water from radionuclides containing sequentially arranged and interconnected receiver tanks, tanks for deposition with dispensers to enter the chemical reagent reservoirs, sumps and storage tanks for radiaktivnogo sludge, characterized in that it further comprises a sorption unit, an input connected to receiver tanks, and output containers for deposition and storage tanks for radioactive sludge performed mnogosektsionye preferably 4 to 6 sections.

7. Installation according to p. 6, characterized in that each of the sections for the storage of radioactive sludge is a series of steel or plastic barrels with a capacity of 200 l each.

 

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FIELD: training tools and devices for the training process.

SUBSTANCE: the invention is dealt with the field of training tools and devices for the training process, in particular, with research of engineering and technology of the automated water supply systems, automatic control of a water supply system in a training process using engineering tools of the new information technologies of training. The multifunctional automated complex training-research laboratory consists of blocks connected in series and-or in parallel through intermediate tanks and devices of water-pump over and a water purification. The laboratory has a pumping plant of the first water rise connected by pressure conduits with chambers of switching with an intermediate tank of influent water, which through a pumping plant of the second water rise is interconnected with the technological apparatuses and blocks of the automated plant of the water purification including a block of clarification of water by settling, consisting of a chamber of a flocculation, a horizontal settler, a block of a reactant system, a block of a clarification of water in a suspension layer, including an air separator connected with a clarifier containing a suspended slurry bed, a block of a water clarification by filtration, that consists of a non-pressure fast and a pressure fast or ultra-speed filter with an intermediate tank of a clarified water, which through the pumping plant of the second water rise is connected to the apparatus of disinfection of water and is connected with an intermediate tank of purified water. The laboratory has an automated system of control over technological processes and a supervisory console with use of a PC and a symbolic circuit. The technical result is creation and implementation in the training-research process of the multifunction automated complex training-research laboratory operating in conditions of model engineering of real water supply systems.

EFFECT: the invention presents a created and introduced multifunction automated complex training-research laboratory operating in the real water supply systems.

18 cl, 7 dwg

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