Powder resin purification device for boron-containing water in spent fuel pool of nuclear power station

Abstract

The invention belongs to the technical field of water quality purification of nuclear power plant spent fuel pool boron-containing water, and particularly relates to a nuclear power plant spent fuel pool boron-containing water powder resin purification device. A filtering element assembly is arranged in the powder resin filter, a pipeline at the top of the powder resin filter is connected with one end of an outlet control valve, one end of a film laying control valve C and one end of a maintaining valve A, the other end of the maintaining valve A is connected with a maintaining pump, and the other end of the film laying control valve C is connected with a powder resin pulping tank. A bottom pipeline of the powder resin filter is respectively connected with one ends of a demineralized water control valve A, an unloading control valve, a film paving control valve B, a maintaining valve B and an inlet control valve, and an upper pipeline of the powder resin filter is respectively connected with one ends of a demineralized water control valve B and a compressed air control valve; and the other end of the demineralized water control valve B is respectively connected with one end of the demineralized water control valve C and the other end of the demineralized water control valve A. According to the invention, the boron-containing water in the spent fuel pool is purified, and meanwhile, the increase of sulfate ions in the purified boron-containing water is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of water purification of boron-containing water in a spent fuel pool of a nuclear power plant, and in particular relates to a powder resin purification device for boron-containing water in a spent fuel pool of a nuclear power plant. Background Art

[0002] Pressurized water reactor nuclear power plants are designed with spent fuel pools for storing spent fuel. Boric water is filled into the spent fuel pools to soak the spent fuel. As the system runs, the mechanical impurities and dissolved impurities in the boron-containing water in the spent fuel pools increase, the transparency decreases, and the water quality deviates from the requirements of the water chemistry outline. In order to ensure that the quality of the boron-containing water in the spent fuel pool meets the requirements, a spent fuel pool purification system is designed to treat the boron-containing water. A typical spent fuel pool purification system is designed with a mechanical filter, a cation exchanger, and an anion exchanger. The mechanical filter is loaded with nuclear-grade cation exchange resin, which is mainly used to remove mechanical impurities and dissolved impurities in the boron-containing water. Due to its high temperature, high oxidation and high irradiation characteristics, the boron-containing water in the spent fuel pool causes the yellow acid group in the cation exchange resin in the mechanical filter to oxidize to generate sulfate ions, resulting in water quality deviation. Sulfate ions are corrosive to equipment and affect the safety of equipment operation, so measures need to be taken to control the concentration of sulfate ions. Summary of the invention

[0003] The object of the present invention is to provide a powder resin purification device for boron-containing water in a spent fuel pool of a nuclear power plant, so as to purify the boron-containing water in the spent fuel pool and avoid the increase of sulfate ions in the purified boron-containing water.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A powder resin purification device for boron-containing water in a spent fuel pool of a nuclear power plant, wherein a filter element assembly is arranged in a powder resin filter, a top pipeline of the powder resin filter is respectively connected to an outlet control valve, a film laying control valve C, and one end of a maintaining valve A, the other end of the maintaining valve A is connected to a maintaining pump, the other end of the film laying control valve C is connected to a powder resin slurry tank, a bottom pipeline of the powder resin filter is respectively connected to a desalted water control valve A, an unloading control valve, a film laying control valve B, a maintaining valve B, and one end of an inlet control valve, and an upper pipeline of the powder resin filter is respectively connected to a desalted water control valve B, a compressed air control valve The other end of the desalted water control valve B is connected to one end of the desalted water control valve C and the other end of the desalted water control valve A respectively, the other end of the desalted water control valve C is connected to the other end of the film laying control valve C, the other end of the film laying control valve B is connected to the film laying pump, the other end of the maintaining valve B is connected to the maintaining pump, the film laying pump is connected to one end of the film laying control valve A, the other end of the film laying control valve A is connected to the bottom of the powder resin slurry making pot, an agitator is arranged in the powder resin slurry making pot, a loading control valve is arranged on the top of the powder resin slurry making pot, and a funnel is arranged on the top of the loading control valve.

[0006] (I) Preparation of powder resin slurry: The powder resin powder is made by mixing cationic powder resin and anionic powder resin in a ratio of 1:1. First, check and close the desalted water control valve C, the loading control valve and the film laying control valve A and the film laying control valve C; open the loading control valve and load the mixed powder resin into the powder resin slurry tank from the funnel; open the desalted water control valve C, inject an appropriate amount of desalted water into the powder resin slurry tank and then close the desalted water control valve C; start the agitator to evenly stir the powder resin in the powder resin slurry tank and make it into a uniform slurry, thus completing the preparation of the powder resin slurry.

[0007] (ii) Film laying: Before film laying, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, desalted water control valve C, compressed air control valve, loading control valve, film laying control valve A, film laying control valve B, film laying control valve C, maintaining valve A, maintaining valve B; open film laying control valve A, film laying control valve B, film laying control valve C; start the film laying pump; and evenly spread the powder resin slurry on the filter element assembly.

[0008] (III) Membrane maintenance: The filter element assembly has been membrane-laid, and when it is not put into operation, the device needs to be put into membrane maintenance mode. Before putting into membrane maintenance mode, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, compressed air control valve, membrane-laid control valve B, membrane-laid control valve C, maintenance valve A, maintenance valve B, open maintenance valve A, maintenance valve B, start the maintenance pump, and the device will enter membrane maintenance mode.

[0009] (IV) Purification of boron-containing water: When purifying boron-containing water, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, desalted water control valve C, compressed air control valve, loading control valve, film laying control valve B, film laying control valve C, maintaining valve A, maintaining valve B before putting into operation, open the inlet control valve and outlet control valve, and the device will enter the operation mode of purifying boron-containing water.

[0010] (V) Membrane unloading: When the pressure difference of the powder resin filter is greater than the set value or the purified water quality does not meet the requirements, the membrane on the filter element assembly should be replaced, that is, the failed membrane should be unloaded and then re-laid. The membrane should be shut down before unloading, including the above (I), (II), and (III) operation modes, check and close the inlet control valve, outlet control valve, unloading control valve, deionized water control valve A, deionized water control valve B, deionized water control valve C, compressed air control valve, film laying control valve B, film laying control valve C, maintenance valve A, maintenance valve B, open the unloading control valve to drain water to the waste resin receiving system, perform the operation of quickly opening and closing the compressed air control valve C, let the powder resin film on the filter element assembly fall off, that is, perform the film blowing operation, and then open the deionized water control valve B to flush the waste powder resin film to the waste resin receiving system. The above film blowing and flushing operations can be repeated many times until the powder resin film on the filter element assembly is completely unloaded.

[0011] A differential pressure gauge is provided between the top pipeline and the bottom pipeline of the powder resin filter.

[0012] The device ensures that the boron-containing water quality meets the following requirements: pH value ≥4.2; chloride ion ≤0.1mg / l; fluoride ion ≤0.1mg / l; sulfate ion ≤0.2mg / l; total organic carbon ≤1mg / l; transparency ≥95%.

[0013] The beneficial effects achieved by the present invention are:

[0014] The invention solves the problem that the increase of sulfate ions in the purification of boron-containing water in a spent fuel pool leads to the deviation of the water quality of the primary circuit, realizes the purification of the boron-containing water in the spent fuel pool, and effectively controls the generation of sulfate ions.

[0015] The present invention realizes powder resin slurry preparation, film laying, film maintenance, boron-containing water purification and film unloading; the device of the present invention is provided with a powder resin slurry preparation tank, a stirrer, a funnel, and a deionized water control valve C for preparing powder resin slurry; the device of the present invention is provided with a film laying pump, a film laying control valve A, a film laying control valve B, and a film laying control valve C for laying powder resin slurry film on a filter element component; the device of the present invention is provided with a maintenance pump, a maintenance valve A, and a maintenance valve B for preventing the powder resin film on the filter element component from falling off under the action of gravity when the powder resin filter is in standby mode in the absence of water pressure; the device of the present invention is provided with an unloading control valve, a deionized water control valve B, and a compressed air control valve for unloading powder resin on the filter element component in the powder resin filter; the device of the present invention is provided with a powder resin filter, a filter element component, an inlet control valve, and an outlet control valve for purifying boron-containing water; the device of the present invention is provided with a differential pressure gauge for measuring the pressure difference of the powder resin filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a boron-containing water powder resin purification device for a spent fuel pool in a nuclear power plant;

[0017] In the figure: 1-powder resin filter, 2-powder resin slurry filling, 3-film laying pump, 4-maintenance pump, 5-filter element assembly, 6-agitator, 7-funnel, 8-inlet control valve, 9-outlet control valve, 10-unloading control valve, 11-desalt water control valve A, 12-desalt water control valve B, 13-desalt water control valve C, 14-compressed air control valve, 15-charging control valve, 16-film laying control valve A, 17-film laying control valve B, 18-film laying control valve C, 19-maintenance valve A, 20-maintenance valve B, 21-differential pressure gauge. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Pressurized water reactor nuclear power plants are designed with spent fuel pools for storing spent fuel. Boron-containing water is filled in the spent fuel pool to soak the spent fuel. As the system runs, the boron-containing water in the spent fuel pool flushes the equipment, causing varying degrees of corrosion to the equipment, and its corrosion products will enter the boron-containing water. At the same time, a small amount of activation and fission products also enter the boron-containing water in the spent fuel pool, causing the water quality to deviate from the requirements of the water chemistry outline. In order to ensure that the quality of the boron-containing water in the spent fuel pool meets the requirements, a spent fuel pool purification system is designed to treat the boron-containing water. A typical spent fuel pool purification system is designed with a mechanical filter, a cation exchanger, and an anion exchanger. The mechanical filter is loaded with nuclear-grade cation exchange resin, which is mainly used for mechanical impurities and dissolved impurities. Due to its high temperature, high oxidizing properties and high irradiation, the boron-containing water in the spent fuel pool causes the yellow acid group in the cation exchange resin in the mechanical filter to oxidize to generate sulfate ions, resulting in water quality deviation. Excessive sulfate concentration has a corrosive effect on the equipment and reduces the operating life of the equipment. Measures should be taken to control the concentration of sulfate ions. In order to solve the problem of the release of sulfate ions by nuclear-grade cationic resins used in the traditional spent fuel pool boron-containing water purification, which leads to an increase in sulfate ions in the boron-containing water, a new purification device was designed. The device no longer uses nuclear-grade cationic resins, thus fundamentally solving the above problem. The newly designed device uses powdered resin to exchange and filter mechanical impurities and other metal ions in boron-containing water, thereby achieving the purification of boron-containing water in the spent fuel pool.

[0020] This device Figure 1 As shown, it includes: 1-powder resin filter, 2-powder resin slurry filling, 3-film laying pump, 4-maintenance pump, 5-filter element assembly, 6-agitator, 7-funnel, 8-inlet control valve, 9-outlet control valve, 10-unloading control valve, 11-desalt water control valve A, 12-desalt water control valve B, 13-desalt water control valve C, 14-compressed air control valve, 15-charging control valve, 16-film laying control valve A, 17-film laying control valve B, 18-film laying control valve C, 19-maintenance valve A, 20-maintenance valve B, 21-differential pressure gauge.

[0021] A filter element assembly 5 is provided in the powder resin filter 1. The top pipeline of the powder resin filter 1 is respectively connected to one end of the outlet control valve 9, the film laying control valve C18 and the maintaining valve A19. The other end of the maintaining valve A19 is connected to the maintaining pump 4. The other end of the film laying control valve C18 is connected to the powder resin slurry tank 2. The bottom pipeline of the powder resin filter 1 is respectively connected to one end of the desalted water control valve A11, the unloading control valve 10, the film laying control valve B17, the maintaining valve B20 and the inlet control valve 8. A differential pressure gauge 21 is provided between the top pipeline and the bottom pipeline of the powder resin filter 1. The upper pipeline of the powder resin filter 1 is respectively connected to the desalted water control valve B12, the compressed air control valve 14, the other end of the desalted water control valve B12 is connected to one end of the desalted water control valve C13 and the other end of the desalted water control valve A11 respectively, the other end of the desalted water control valve C13 is connected to the other end of the film laying control valve C18, the other end of the film laying control valve B17 is connected to the film laying pump 3, the other end of the maintaining valve B20 is connected to the maintaining pump 4, the film laying pump 3 is connected to one end of the film laying control valve A16, the other end of the film laying control valve A16 is connected to the bottom of the powder resin slurry pot 2, an agitator 6 is provided in the powder resin slurry pot 2, a charging control valve 15 is provided on the top of the powder resin slurry pot 2, and a funnel 7 is provided on the top of the charging control valve 15.

[0022] The present invention can realize powder resin slurry preparation, film laying, film maintenance, boron-containing water purification and film unloading; the present invention is provided with 2-powder resin slurry preparation tank, 6-agitator, 7-funnel, 13-deionized water valve C, to realize resin slurry preparation; the present invention is provided with 3-film laying pump, 16-film laying control valve A, 17-film laying control valve B, 18-film laying control valve C, to realize 5-filter element assembly to lay powder resin slurry film; the present invention is provided with 4-maintenance pump, 19-maintenance valve A, 20-maintenance valve B, to realize 1-powder resin filter in standby The invention provides membrane protection to prevent the powder resin membrane on the 5-filter element assembly from falling off under the action of gravity in the absence of water pressure; the invention is provided with 10-unloading control valve, 12-desalting water valve B, 14-pressure control valve, so as to realize the unloading of the powder resin membrane on the 5-filter element assembly in the 1-powder resin filter; the invention is provided with 1-powder resin filter, 5-filter element assembly, 8-inlet control valve, 9-outlet control valve, so as to realize the purification of boron-containing water; the invention is provided with 20-differential pressure gauge, so as to realize the pressure difference monitoring of the 1-powder resin filter.

[0023] The device ensures that the boron-containing water quality meets the following requirements: pH value: ≥4.2; chloride ion: ≤0.1mg / l; fluoride ion: ≤0.1mg / l; sulfate ion: ≤0.2mg / l; total organic carbon: ≤1mg / l; transparency: ≥95%.

[0024] The device mainly has operating functions such as powder resin slurry preparation, film laying, membrane maintenance, boron-containing water purification and membrane unloading, which are described below respectively.

[0025] (I) Preparation of powder resin slurry

[0026] The powdered resin powder of the device is made of a mixture of cationic powdered resin and anionic powdered resin in a ratio of 1:1. First, check and close the deionized water control valve C13, the loading control valve 15, the film laying control valve A16, and the film laying control valve C18; open the loading control valve 15, and load the mixed powdered resin into the powdered resin slurry tank 2 from the funnel 7; open the deionized water control valve C13, inject a proper amount of deionized water into the powdered resin slurry tank 2, and then close the deionized water control valve C13; start the agitator 6 to stir the powdered resin in the powdered resin slurry tank 2 evenly and form a uniform slurry, thus completing the preparation of the powdered resin slurry.

[0027] (ii) Film laying

[0028] Before film laying, check and close the inlet control valve 8, outlet control valve 9, unloading control valve 10, desalted water control valve A11, desalted water control valve B12, desalted water control valve C13, compressed air control valve 14, loading control valve 15, film laying control valve A16, film laying control valve B17, film laying control valve C18, maintenance valve A19, maintenance valve B20. Open film laying control valve A16, film laying control valve B17, film laying control valve C18, start the film laying pump 3, and evenly spread the powder resin slurry on the filter element assembly 5.

[0029] (III) Membrane maintenance

[0030] The filter element assembly 5 has been laid with membrane, and when the system is not put into operation, the device needs to be put into membrane maintenance mode to prevent the membrane of the filter element assembly 5 from falling off under gravity. Before putting into membrane maintenance mode, check and close the inlet control valve 8, outlet control valve 9, unloading control valve 10, desalted water control valve A11, desalted water control valve B12, compressed air control valve 14, membrane laying control valve B17, membrane laying control valve C18, maintenance valve A19, and maintenance valve B20. Open maintenance valve A19 and maintenance valve B20, start maintenance pump 4, and the device will enter membrane maintenance mode.

[0031] (IV) Purification of Boron-containing Water

[0032] When purifying boron-containing water, check and close the inlet control valve 8, outlet control valve 9, unloading control valve 10, desalted water control valve A11, desalted water control valve B12, desalted water control valve C13, compressed air control valve 14, loading control valve 15, film laying control valve B17, film laying control valve C18, maintenance valve A19, and maintenance valve B20 before commissioning. Open the inlet control valve 8 and outlet control valve 9, and the device will enter the operation mode of purifying boron-containing water.

[0033] (V) Membrane unloading

[0034] When the pressure difference of the powder resin filter 1 is greater than the set value, or the purified water quality does not meet the requirements, the membrane on the filter element assembly 5 should be replaced, that is, the failed membrane should be unloaded and re-laid.

[0035] Before unloading the membrane, shut down the system first, including the above (i) (ii) (iii) operation modes. Check and close the inlet control valve 8, outlet control valve 9, unloading control valve 10, desalted water control valve A11, desalted water control valve B12, desalted water control valve C13, compressed air control valve 14, film laying control valve B17, film laying control valve C18, maintaining valve A19, and maintaining valve B20. Open the unloading control valve 10 to drain the waste resin receiving system, and quickly open and close the compressed air control valve C14 to let the powder resin film on the filter element assembly 5 fall off, that is, perform the film blowing operation. Then open the desalted water control valve B12 to flush the waste powder resin film to the waste resin receiving system. The above-mentioned film blowing and flushing operations can be repeated many times until the powder resin film on the filter element assembly 5 is completely unloaded.

[0036] The powder resin purification device is used to purify mechanical impurities and other metal ions in boron-containing water, while avoiding the generation of sulfate ions. my country vigorously develops nuclear energy and nuclear technology. The device of the present invention can be widely used in the field of purification of boron-containing water in pressurized water reactor nuclear power plants due to its simple construction, convenient and reliable use.

Claims

1. A boron-containing water powder resin purification device for a spent fuel pool in a nuclear power plant, characterized in that: The powder resin filter is provided with a filter element assembly. The top pipeline of the powder resin filter is respectively connected to the outlet control valve, the film laying control valve C, and one end of the maintaining valve A. The other end of the maintaining valve A is connected to the maintaining pump. The other end of the film laying control valve C is connected to the powder resin slurry tank. The bottom pipeline of the powder resin filter is respectively connected to the desalted water control valve A, the unloading control valve, the film laying control valve B, the maintaining valve B, and one end of the inlet control valve. The upper pipeline of the powder resin filter is respectively connected to the desalted water control valve B and one end of the compressed air control valve. The other end of the control valve B is respectively connected to one end of the desalted water control valve C and the other end of the desalted water control valve A, the other end of the desalted water control valve C is connected to the other end of the film laying control valve C, the other end of the film laying control valve B is connected to the film laying pump, the other end of the maintaining valve B is connected to the maintaining pump, the film laying pump is connected to one end of the film laying control valve A, the other end of the film laying control valve A is connected to the bottom of the powder resin slurry making tank, an agitator is arranged in the powder resin slurry making tank, a loading control valve is arranged on the top of the powder resin slurry making tank, and a funnel is arranged on the top of the loading control valve.

2. The boron water powder resin purification device for spent fuel pools in nuclear power plants according to claim 1, characterized in that: (I) Preparation of powder resin slurry: The powder resin powder is made by mixing cationic powder resin and anionic powder resin in a ratio of 1:

1. First, check and close the desalted water control valve C, the loading control valve and the film laying control valve A and the film laying control valve C; open the loading control valve and load the mixed powder resin into the powder resin slurry tank from the funnel; open the desalted water control valve C, inject an appropriate amount of desalted water into the powder resin slurry tank and then close the desalted water control valve C; start the agitator to evenly stir the powder resin in the powder resin slurry tank and make it into a uniform slurry, thus completing the preparation of the powder resin slurry.

3. The boron-containing water powder resin purification device for spent fuel pools in nuclear power plants according to claim 2, characterized in that: (ii) Film laying: Before film laying, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, desalted water control valve C, compressed air control valve, loading control valve, film laying control valve A, film laying control valve B, film laying control valve C, maintaining valve A, maintaining valve B; open film laying control valve A, film laying control valve B, film laying control valve C; start the film laying pump; and evenly spread the powder resin slurry on the filter element assembly.

4. The boron-containing water powder resin purification device for spent fuel pools in nuclear power plants according to claim 3, characterized in that: (III) Membrane maintenance: The filter element assembly has been membrane-laid, and when it is not put into operation, the device needs to be put into membrane maintenance mode. Before putting into membrane maintenance mode, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, compressed air control valve, membrane-laid control valve B, membrane-laid control valve C, maintenance valve A, maintenance valve B, open maintenance valve A, maintenance valve B, start the maintenance pump, and the device will enter membrane maintenance mode.

5. The boron-containing water powder resin purification device for spent fuel pools in nuclear power plants according to claim 4, characterized in that: (IV) Purification of boron-containing water: When purifying boron-containing water, check and close the inlet control valve, outlet control valve, unloading control valve, desalted water control valve A, desalted water control valve B, desalted water control valve C, compressed air control valve, loading control valve, film laying control valve B, film laying control valve C, maintaining valve A, maintaining valve B before putting into operation, open the inlet control valve and outlet control valve, and the device will enter the operation mode of purifying boron-containing water.

6. The boron-containing water powder resin purification device for spent fuel pools in nuclear power plants according to claim 5, characterized in that: (V) Membrane unloading: When the pressure difference of the powder resin filter is greater than the set value or the purified water quality does not meet the requirements, the membrane on the filter element assembly should be replaced, that is, the failed membrane should be unloaded and then re-laid. The membrane should be shut down before unloading, including the above (I), (II), and (III) operation modes, check and close the inlet control valve, outlet control valve, unloading control valve, deionized water control valve A, deionized water control valve B, deionized water control valve C, compressed air control valve, film laying control valve B, film laying control valve C, maintenance valve A, maintenance valve B, open the unloading control valve to drain water to the waste resin receiving system, perform the operation of quickly opening and closing the compressed air control valve C, let the powder resin film on the filter element assembly fall off, that is, perform the film blowing operation, and then open the deionized water control valve B to flush the waste powder resin film to the waste resin receiving system. The above film blowing and flushing operations can be repeated many times until the powder resin film on the filter element assembly is completely unloaded.

7. The boron water powder resin purification device for spent fuel pools in nuclear power plants according to claim 1, characterized in that: A differential pressure gauge is provided between the top pipeline and the bottom pipeline of the powder resin filter.

8. The boron-containing water powder resin purification device for spent fuel pools in nuclear power plants according to claim 1, characterized in that: The device ensures that the boron-containing water quality meets the following requirements: pH value ≥4.2; chloride ion ≤0.1mg / l; fluoride ion ≤0.1mg / l; sulfate ion ≤0.2mg / l; total organic carbon ≤1mg / l; transparency ≥95%.

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