Recovery system and method for boric acid solution of nuclear power plant

Abstract

The invention relates to the field of nuclear power plant reactor operation, in particular to a nuclear power plant boric acid solution recovery system and method. The system comprises a front storage tank, one end of the front storage tank is connected with a primary loop of a reactor, the other end of the front storage tank is sequentially connected with at least three middle storage tanks, an evaporator, a boric acid storage tank and a refueling water tank, a bidirectional boron transfer pipeline is arranged between the middle storage tanks and the refueling water tank, and a reactor water tank, a component tank and a loading well are respectively connected with the refueling water tank. The effects of recycling the boric acid solution, avoiding environmental pollution and shortening the overhaul period are achieved.

Description

Technical Field

[0001] The present invention relates to the field of reactor operation in nuclear power plants, and particularly to a boric acid solution recovery system and method for nuclear power plants. Background Art

[0002] Boric acid is widely used in nuclear power plants to control the reactivity of reactors. To recover the boric acid solution discharged from the primary loop of the reactor, a boric acid solution recovery system is designed in nuclear power plants.

[0003] According to the initial design of the boric acid solution recovery system, its working process is as follows: first, collect the boric acid solution discharged from the primary loop of the reactor, then evaporate and concentrate it into a high-concentration boric acid solution, then transfer it to a boric acid solution storage tank for storage, and finally, as needed, inject the high-concentration boric acid solution into the primary loop of the reactor and configure a boric acid solution with a concentration of 2400 ppm in the refueling water tank, so as to achieve the purpose of recovering the boric acid solution.

[0004] The process of evaporating and concentrating the boric acid solution discharged from the primary loop of the reactor into a high-concentration boric acid solution takes a long time, resulting in that during the short outage of the nuclear power plant, the evaporated and concentrated high-concentration boric acid solution cannot be transferred to the boric acid solution storage tank for storage and recovery. This is because during the short outage of the nuclear power plant, before the work of evaporating and concentrating into a high-concentration boric acid is completed, according to the requirements of the unit operating conditions, the boric acid solution storage tank has been filled with high-concentration boric acid solution by other methods, which causes the evaporated and concentrated high-concentration boric acid solution to be unable to be recovered and can only be discharged into the environment as production wastewater, resulting in boric acid waste and environmental pollution. Therefore, during the short outage of the nuclear power plant, the boric acid solution recovery system of the nuclear power plant cannot achieve the purpose of recovering the boric acid solution.

[0005] In addition, according to the safety requirements of nuclear power plants, the lap welds of the bottom plate of the refueling water tank need to be comprehensively inspected regularly. When conducting a comprehensive inspection, it is necessary to empty the boric acid solution in the refueling water tank. The current method is to discharge all the boric acid solution in the refueling water tank into the environment or partially recover it. The method of discharging all into the environment causes boric acid waste and environmental pollution; the method of partial recovery is to temporarily store a part of the boric acid solution in the refueling water tank in the reactor pool and discharge the remaining part into the environment as wastewater. After the refueling water tank is emptied and repaired, then transfer the boric acid solution temporarily stored in the reactor pool back to the refueling water tank. Since the reactor pool is connected to the primary loop of the reactor, when a part of the boric acid solution in the refueling water tank is temporarily stored in the reactor pool, the primary loop of the reactor cannot be emptied, and the related equipment of the primary loop of the reactor cannot be repaired. And the repair of the related equipment of the primary loop of the reactor is one of the most time-consuming works during the overhaul of the nuclear power plant, which leads to the extension of the overhaul period of the nuclear power plant, and there are still problems of boric acid waste and environmental pollution when the remaining part of the boric acid solution in the refueling water tank is discharged into the environment. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a boric acid solution recovery system and method for nuclear power plants, which achieve the effects of recovering boric acid solution, avoiding environmental pollution and shortening the overhaul period.

[0007] The present invention provides a boric acid solution recovery system for nuclear power plants, comprising:

[0008] A front storage tank, one end of which is connected to the primary circuit of the reactor, and the other end is successively connected to an intermediate storage tank, an evaporator, a boric acid storage tank and a refueling water tank;

[0009] The intermediate storage tanks are at least 3 in parallel;

[0010] A two-way boron transfer pipeline is arranged between the intermediate storage tank and the refueling water tank;

[0011] The reactor pool, the component pool and the loading well are respectively connected to the refueling water tank.

[0012] In a specific embodiment of the present invention, the two-way boron transfer pipeline comprises three branches;

[0013] Both ends of the first branch are the intermediate storage tank and the refueling water tank respectively;

[0014] A first valve, a second valve, a boron transfer pump, a third valve and a fourth valve are successively arranged on the first branch;

[0015] One end of the second branch is connected between the first valve and the second valve, and the other end is connected to the outlet end of the boron transfer pump; a fifth valve is arranged on the second branch;

[0016] One end of the third branch is connected to the inlet end of the boron transfer pump, and the other end is connected between the third valve and the fourth valve; a sixth valve is arranged on the third branch.

[0017] In a specific embodiment of the present invention, a detachable air lock is installed between the reactor pool and the component pool.

[0018] The present invention provides a boric acid solution recovery method for nuclear power plants, comprising: recovering the boric acid solution discharged from the primary circuit of the reactor and recovering the boric acid solution in the refueling water tank;

[0019] The recovery of the boric acid solution discharged from the primary circuit of the reactor is specifically as follows:

[0020] Judge the concentration of the boric acid solution discharged from the primary circuit of the reactor. If it is less than 2400 ppm, the discharged boric acid solution is concentrated to 2400 ppm in the evaporator, and then stored in the boric acid storage tank until the refueling water tank is available and then transferred to the refueling water tank;

[0021] If the concentration of the boric acid solution discharged from the primary circuit of the reactor is equal to 2400 ppm, the discharged boric acid solution is stored in any two intermediate storage tanks with sufficient capacity until it can be transferred to the refueling water tank after the refueling water tank becomes available;

[0022] The recovery of the boric acid solution in the refueling water tank is specifically as follows:

[0023] Before discharging the fuel, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool and the component pool until the reactor pool and the component pool are full;

[0024] After the reactor fuel is discharged, only the boric acid solution in the reactor pool is transferred back to the refueling water tank;

[0025] Before the refueling water tank is overhauled, a part of the boric acid solution in the refueling water tank is transferred to any two intermediate storage tanks with sufficient capacity through a two-way boron transfer pipeline until the two intermediate storage tanks are full, and the remaining boric acid solution in the refueling water tank is transferred to the loading well;

[0026] After the refueling water tank is overhauled, the boric acid solution in the intermediate storage tank is transferred back to the refueling water tank through a two-way boron transfer pipeline;

[0027] The boric acid solution in the loading well is transferred back to the refueling water tank;

[0028] Before the reactor is loaded with fuel, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool until the reactor pool is full;

[0029] After the reactor is loaded with fuel, the boric acid solution in the reactor pool and the component pool is transferred back to the refueling water tank.

[0030] In a specific embodiment of the present invention, the operating conditions where the concentration of the boric acid solution discharged from the primary circuit of the reactor is less than 2400 ppm include: the period from when the concentration of the boric acid solution discharged from the primary circuit of the reactor is less than 2400 ppm during the reactor startup process to before the concentration of the boric acid discharged from the primary circuit of the reactor reaches 2400 ppm during the reactor shutdown process;

[0031] The operating conditions where the concentration of the boric acid solution discharged from the primary circuit of the reactor is equal to 2400 ppm include: the period from when the concentration of the boric acid solution discharged from the primary circuit of the reactor reaches 2400 ppm during the reactor shutdown process to before the concentration of the boric acid solution discharged from the primary circuit of the reactor is less than 2400 ppm during the reactor startup process.

[0032] In a specific embodiment of the present invention, after the reactor fuel is discharged, an air lock is installed between the reactor pool and the component pool, and the boric acid solution in the component pool is not transferred back to the refueling water tank, and only the boric acid solution in the reactor pool is transferred back to the refueling water tank.

[0033] In a specific embodiment of the present invention, before loading the reactor, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool until the reactor pool is full, and the air lock between the reactor pool and the component pool is removed.

[0034] In a specific embodiment of the present invention, when recovering the boric acid solution discharged from the primary circuit of the reactor;

[0035] If the concentration of the boric acid solution discharged from the primary circuit of the reactor is equal to 2400 ppm, the discharged boric acid solution is stored in any two intermediate storage tanks with sufficient capacity;

[0036] When the refueling water tank does not need to be overhauled, the boric acid solution is directly transferred to the refueling water tank through the two-way boron transfer pipeline;

[0037] When the refueling water tank needs to be overhauled, after the overhaul of the refueling water tank is completed, the boric acid solution is transferred to the refueling water tank through the two-way boron transfer pipeline.

[0038] In a specific embodiment of the present invention, when recovering the boric acid solution in the refueling water tank, before overhauling the refueling water tank, a part of the boric acid solution in the refueling water tank is transferred to any two intermediate storage tanks with sufficient capacity through the two-way boron transfer pipeline;

[0039] The operation method of the two-way boron transfer pipeline is as follows:

[0040] The first valve, the fourth valve, the fifth valve and the sixth valve are opened; the second valve and the third valve are closed, and the boron transfer pump is started;

[0041] When recovering the boric acid solution in the refueling water tank, after overhauling the refueling water tank, the boric acid solution in the intermediate storage tank is transferred back to the refueling water tank through the two-way boron transfer pipeline. The operation method of the two-way boron transfer pipeline is as follows:

[0042] The first valve, the second valve, the third valve and the fourth valve are opened; the fifth valve and the sixth valve are closed, and the boron transfer pump is started.

[0043] Compared with the prior art, the boric acid solution recovery system and method of the present invention have the following beneficial effects:

[0044] (1) The boric acid solution discharged from the primary circuit of the reactor is recovered in two ways according to the concentration. For the boric acid solution with a concentration less than 2400 ppm discharged from the primary circuit of the reactor, the target boron concentration for evaporation and concentration is reduced from a high concentration to 2400 ppm, shortening the evaporation and concentration time and improving the recovery efficiency of the boric acid solution with a concentration less than 2400 ppm. During the short overhaul of the nuclear power plant, the purpose of recovering the boric acid solution with a concentration less than 2400 ppm discharged from the primary circuit of the reactor is achieved;

[0045] (2)For the boric acid solution with a concentration of 2400 ppm discharged from the primary circuit of the reactor, without evaporation and concentration, by adding a two-way boron transfer pipeline between the intermediate storage tank and the refueling water tank, the 2400-ppm boric acid solution discharged from the primary circuit of the reactor is directly transferred from the intermediate storage tank to the refueling water tank, improving the recovery efficiency of the 2400-ppm boric acid solution. During the short outage of the nuclear power plant, the purpose of recovering the 2400-ppm boric acid solution discharged from the primary circuit of the reactor is achieved;

[0046] (3)When the refueling water tank is emptied for maintenance, using the storage space of the component pool, by installing an air lock between the reactor pool and the component pool, a part of the boric acid solution in the refueling water tank is temporarily stored in the component pool. After the reactor is loaded, it is then transferred back to the refueling water tank;

[0047] (4)When the refueling water tank is emptied for maintenance, using the storage space of the intermediate storage tank, by adding a two-way boron transfer pipeline between the intermediate storage tank and the refueling water tank, a part of the boric acid solution in the refueling water tank is temporarily stored in the intermediate storage tank. After the refueling water tank is emptied and the maintenance is completed, it is then transferred back to the refueling water tank;

[0048] (5)When the refueling water tank is emptied for maintenance, using the storage space of the loading well, a part of the boric acid solution in the refueling water tank is temporarily stored in the loading well. After the refueling water tank is emptied and the maintenance is completed, it is then transferred back to the refueling water tank;

[0049] (6)When the refueling water tank is emptied for maintenance, the storage spaces of the intermediate storage tank, the loading well, and the component pool are sufficient to temporarily store all the boric acid solution in the refueling water tank. The reactor pool does not need to temporarily store a part of the boric acid solution in the refueling water tank. The primary circuit of the reactor can still be emptied for maintenance. The maintenance work of the refueling water tank does not affect the maintenance work of the related equipment in the primary circuit of the reactor and will not extend the outage duration. Description of the Drawings

[0050] Figure 1 Shows a schematic diagram of the boric acid solution recovery system in a nuclear power plant;

[0051] Figure 2 Shows a schematic diagram of the two-way boron transfer pipeline between the intermediate storage tank and the refueling water tank;

[0052] Figure 3 Shows a flowchart of the boric acid solution recovery method in a nuclear power plant;

[0053] In the figure:

[0054] 1 - Primary circuit of the reactor, 2 - Front storage tank, 3 - First intermediate storage tank, 4 - Second intermediate storage tank, 5 - Third intermediate storage tank, 6 - Evaporator, 7 - Boric acid solution storage tank, 8 - Reactor pool, 9 - Component pool, 10 - Loading well, 11 - Refueling water tank, 12 - Bidirectional boron transfer pipeline, 13 - First valve, 14 - Second valve, 15 - Fifth valve, 16 - Third valve, 17 - Sixth valve, 18 - Fourth valve, 19 - Boron transfer pump, 20 - Air lock. Detailed implementation mode

[0055] To further understand the present invention, the implementation scheme of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the present invention.

[0056] An embodiment of the present invention discloses a boric acid solution recovery system for a nuclear power plant, as Figure 1 shown, including:

[0057] The front storage tank 2 is connected to the primary circuit 1 of the reactor at one end, and is sequentially connected to the intermediate storage tank, the evaporator 6, the boric acid solution storage tank 7 and the refueling water tank 11 at the other end;

[0058] The intermediate storage tank is at least 3 in parallel, specifically, the first intermediate storage tank 3, the second intermediate storage tank 4, and the third intermediate storage tank 5 are in parallel;

[0059] A bidirectional boron transfer pipeline 12 is provided between the intermediate storage tank and the refueling water tank 11;

[0060] The reactor pool 8, the component pool 9 and the loading well 10 are respectively connected to the refueling water tank 11;

[0061] An detachable air lock 20 is provided between the reactor pool 8 and the component pool 9.

[0062] As Figure 2 shown, the bidirectional boron transfer pipeline 12 includes three branches:

[0063] The two ends of the first branch are respectively the intermediate storage tank and the refueling water tank 11;

[0064] The first valve 13, the second valve 14, the boron transfer pump 19, the third valve 16 and the fourth valve 18 are sequentially arranged on the first branch;

[0065] One end of the second branch is connected between the first valve 13 and the second valve 14, and the other end is connected to the outlet end of the boron transfer pump 19; a fifth valve 15 is arranged on the second branch;

[0066] One end of the third branch is connected to the inlet end of the boron transfer pump 19, and the other end is connected between the third valve 16 and the fourth valve 18; a sixth valve 17 is arranged on the third branch.

[0067] An embodiment of the present invention discloses a method for recovering boric acid solution in a nuclear power plant, as Figure 3 shown, including:

[0068] Recovery of the boric acid solution discharged from the primary circuit 1 of the reactor and recovery of the boric acid solution in the refueling water tank 11;

[0069] The recovery of the boric acid solution discharged from the primary circuit 1 of the reactor includes:

[0070] Judging the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor. If it is less than 2400 ppm, it is collected into an intermediate storage tank through the front storage tank 2;

[0071] The intermediate storage tank is preferably the first intermediate storage tank 3;

[0072] Then, the boric acid solution with a concentration less than 2400 ppm in the intermediate storage tank is evaporated and concentrated into a boric acid solution with a concentration of 2400 ppm by the evaporator 6 and stored in the boric acid solution storage tank 7;

[0073] If the refueling water tank 11 does not need to be emptied for maintenance, the boric acid solution with a concentration of 2400 ppm in the boric acid solution storage tank 7 is directly transferred to the refueling water tank 11;

[0074] If the refueling water tank 11 needs to be emptied for maintenance, after the refueling water tank 11 is emptied and the maintenance is completed, the boric acid solution with a concentration of 2400 ppm in the boric acid solution storage tank 7 is transferred to the refueling water tank 11.

[0075] The working conditions of the boric acid solution with a concentration less than 2400 ppm discharged from the primary circuit 1 of the reactor include: the period from when the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor is less than 2400 ppm during the reactor startup process to when the boric acid concentration discharged from the primary circuit 1 of the reactor reaches 2400 ppm before the reactor shutdown process.

[0076] If the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor is 2400 ppm, it is transferred to any two intermediate storage tanks with sufficient capacity through the front storage tank 2;

[0077] The intermediate storage tanks are preferably the second intermediate storage tank 4 and the third intermediate storage tank 5;

[0078] If the refueling water tank 11 does not need to be emptied for maintenance, the boric acid solution with a concentration of 2400 ppm in the intermediate storage tank is directly transferred to the refueling water tank 11 through the two-way boron transfer pipeline 12;

[0079] If the refueling water tank 11 needs to be emptied for maintenance, after the refueling water tank 11 is emptied and the maintenance is completed, the boric acid solution with a concentration of 2400 ppm in the intermediate storage tank is transferred to the refueling water tank 11 through the two-way boron transfer pipeline 12;

[0080] The operating conditions of the boric acid solution with a concentration of 2400 ppm discharged from the primary loop 1 of the reactor include: the period from when the concentration of the boric acid solution discharged from the primary loop 1 of the reactor reaches 2400 ppm during the reactor shutdown process to before the concentration of the boric acid solution discharged from the primary loop 1 of the reactor is less than 2400 ppm during the reactor startup process.

[0081] The recovery of the boric acid solution in the refueling water tank 11 includes:

[0082] Before reactor refueling, a part of the boric acid solution in the refueling water tank 11 is transferred to the reactor pool 8 and the component pool 9 until the reactor pool 8 and the component pool 9 are full;

[0083] After reactor refueling, an air lock 20 is installed between the reactor pool 8 and the component pool 9, and only the boric acid solution in the reactor pool 8 is transferred back to the refueling water tank 11;

[0084] The primary loop 1 is emptied for maintenance of the related equipment of the primary loop 1;

[0085] Before the refueling water tank 11 is maintained, a part of the boric acid solution in the refueling water tank 11 is transferred to any two intermediate storage tanks with sufficient capacity through the two-way boron transfer pipeline 12 until the two intermediate storage tanks are full;

[0086] The intermediate storage tanks are preferably the second intermediate storage tank 4 and the third intermediate storage tank 5;

[0087] Before the refueling water tank 11 is maintained, the remaining boric acid solution in the refueling water tank 11 is transferred to the loading well 10 until the refueling water tank 11 is emptied;

[0088] After the refueling water tank 11 is maintained, the boric acid solution in the two intermediate storage tanks is transferred back to the refueling water tank 11 through the two-way boron transfer pipeline 12;

[0089] After the refueling water tank 11 is maintained, the boric acid solution in the loading well 10 is transferred back to the refueling water tank 11;

[0090] Before reactor loading, a part of the boric acid solution in the refueling water tank 11 is transferred to the reactor pool 8 until the reactor pool 8 is full, and the air lock 20 between the reactor pool 8 and the component pool 9 is removed.

[0091] After reactor loading, the boric acid solution in the reactor pool 8 and the component pool 9 is transferred back to the refueling water tank 11.

[0092] To further understand the present invention, the following describes in detail the nuclear power plant boric acid solution recovery system and method provided by the present invention in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0093] Embodiment 1

[0094] Boric acid solution recovery system for nuclear power plant, as Figure 1 shown, comprising:

[0095] A front storage tank 2, one end of which is connected to the primary circuit 1 of the reactor, and the other end is successively connected to an intermediate storage tank, an evaporator 6, a boric acid solution storage tank 7 and a refueling water tank 11;

[0096] The intermediate storage tank is at least 3 in parallel, specifically, the first intermediate storage tank 3, the second intermediate storage tank 4 and the third intermediate storage tank 5 are in parallel;

[0097] A two-way boron transfer pipeline 12 is arranged between the intermediate storage tank and the refueling water tank 11;

[0098] The reactor pool 8, the component pool 9 and the loading well 10 are respectively connected to the refueling water tank 11;

[0099] A detachable air lock 20 is arranged between the reactor pool 8 and the component pool 9.

[0100] As Figure 2 shown, the two-way boron transfer pipeline 12 includes three branches:

[0101] Both ends of the first branch are respectively the intermediate storage tank and the refueling water tank 11;

[0102] A first valve 13, a second valve 14, a boron transfer pump 19, a third valve 16 and a fourth valve 18 are successively arranged on the first branch;

[0103] One end of the second branch is connected between the first valve 13 and the second valve 14, and the other end is connected to the outlet end of the boron transfer pump 19; a fifth valve 15 is arranged on the second branch;

[0104] One end of the third branch is connected to the inlet end of the boron transfer pump 19, and the other end is connected between the third valve 16 and the fourth valve 18; a sixth valve 17 is arranged on the third branch.

[0105] A method for recovering boric acid solution by using the boric acid solution recovery system for nuclear power plant, as Figure 3 shown, comprising:

[0106] Recovery of the boric acid solution discharged from the primary circuit 1 of the reactor and recovery of the boric acid solution in the refueling water tank 11;

[0107] The recovery of the boric acid solution discharged from the primary circuit 1 of the reactor includes:

[0108] During the period from when the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor is less than 2400 ppm after the reactor starts up to before the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor reaches 2400 ppm during the reactor shutdown process, the concentration of the boric acid solution discharged from the primary circuit 1 of the reactor is less than 2400 ppm.

[0109] For the boric acid solution with a concentration less than 2400 ppm discharged from the primary loop 1 of the above reactor, it is collected into the first intermediate storage tank 3 through the pre-storage tank 2. The target boron concentration for evaporation and concentration by the evaporator 6 is set to 2400 ppm. The boric acid solution with a concentration less than 2400 ppm is evaporated and concentrated into a boric acid solution with a concentration of 2400 ppm by the evaporator 6 and stored in the boric acid solution storage tank 7. This part of the boric acid solution with a concentration of 2400 ppm is about 60 m³.

[0110] If the refueling water tank 11 does not need to be emptied for maintenance, then about 60 m³ of the boric acid solution with a concentration of 2400 ppm in the boric acid solution storage tank 7 is transferred to the refueling water tank 11.

[0111] If the refueling water tank 11 needs to be emptied for maintenance, then after the refueling water tank 11 is emptied and the maintenance is completed, about 60 m³ of the boric acid solution with a concentration of 2400 ppm in the boric acid solution storage tank 7 is transferred to the refueling water tank 11.

[0112] During the period from when the concentration of the boric acid solution discharged from the primary loop 1 of the reactor reaches 2400 ppm during the reactor shutdown process to before the concentration of the boric acid solution discharged from the primary loop 1 of the reactor is less than 2400 ppm during the reactor startup process, the concentration of the boric acid solution discharged from the primary loop 1 of the reactor is equal to 2400 ppm.

[0113] For the boric acid solution with a concentration of 2400 ppm discharged from the primary loop 1 of the above reactor, it is collected into the second intermediate storage tank 4 and the third intermediate storage tank 5 through the pre-storage tank 2. This part of the boric acid solution with a concentration of 2400 ppm is about 100 m³.

[0114] If the refueling water tank 11 does not need to be emptied for maintenance, then about 100 m³ of the boric acid solution with a concentration of 2400 ppm in the second intermediate storage tank 4 and the third intermediate storage tank 5 is transferred to the refueling water tank 11 through the two-way boron transfer pipeline 12.

[0115] If the refueling water tank 11 needs to be emptied for maintenance, then after the refueling water tank 11 is emptied and the maintenance is completed, about 100 m³ of the boric acid solution with a concentration of 2400 ppm in the second intermediate storage tank 4 and the third intermediate storage tank 5 is transferred to the refueling water tank 11 through the two-way boron transfer pipeline 12.

[0116] The operation method of the two-way boron transfer pipeline 12 is as follows:

[0117] The first valve 13, the second valve 14, the third valve 16 and the fourth valve 18 are opened; the fifth valve 15 and the sixth valve 17 are closed, and the boron transfer pump 19 is started. The recovery of the boric acid solution in the refueling water tank 11 includes:

[0118] Before reactor discharge, 1470 m³ of boric acid solution in the refueling water tank 11 is transferred to the reactor pool 8 and the component pool 9 until the reactor pool 8 and the component pool 9 are full;

[0119] After reactor discharge, an air lock 20 is installed between the reactor pool 8 and the component pool 9. 870 m³ of boric acid solution in the component pool 9 is not transferred back to the refueling water tank 11, and 600 m³ of boric acid solution in the reactor pool 8 is transferred back to the refueling water tank 11;

[0120] Empty the primary circuit 1 of the reactor for maintenance of related equipment in the primary circuit 1 of the reactor;

[0121] Before maintenance of the refueling water tank 11, 752 m³ of boric acid solution in the refueling water tank 11 is transferred to the second intermediate storage tank 4 and the third intermediate storage tank 5 through the two-way boron transfer pipeline 12;

[0122] The operation method of the two-way boron transfer pipeline 12 is as follows:

[0123] The first valve 13, the fourth valve 18, the fifth valve 15 and the sixth valve 17 are opened; the second valve 14 and the third valve 16 are closed, and the boron transfer pump 19 is started;

[0124] Before maintenance of the refueling water tank 11, the remaining 230 m³ of boric acid solution in the refueling water tank 11 is transferred to the loading well 10. At this time, the refueling water tank 11 is emptied and ready for maintenance;

[0125] After maintenance of the refueling water tank 11, 752 m³ of boric acid solution in the second intermediate storage tank 4 and the third intermediate storage tank 5 is transferred back to the refueling water tank 11 through the two-way boron transfer pipeline 12;

[0126] The operation method of the two-way boron transfer pipeline 12 is as follows:

[0127] The first valve 13, the second valve 14, the third valve 16 and the fourth valve 18 are opened; the fifth valve 15 and the sixth valve 17 are closed, and the boron transfer pump 19 is started.

[0128] After maintenance of the refueling water tank 11, 230 m³ of boric acid solution in the loading well 10 is transferred back to the refueling water tank 11.

[0129] Before reactor refueling, 600 m³ of boric acid solution in the refueling water tank 11 is transferred to the reactor pool 8, and the air lock 20 between the reactor pool 8 and the component pool 9 is removed.

[0130] After reactor refueling, 1470 m³ of boric acid solution in the reactor pool 8 and the component pool 9 is transferred back to the refueling water tank 11.

[0131] Using the boric acid solution recovery system and method of the present invention for comparison with the initial design of the nuclear power plant, the results are shown in Table 1.

[0132] Table 1 Comparison Table of the Boric Acid Solution Recovery System and Method of the Present Invention with the Initial Design Effect of the Nuclear Power Plant

[0133] As can be seen from Table 1, the present invention solves the problems that the boric acid solution recovery system of the initial design of the nuclear power plant cannot recover the boric acid solution, pollutes the environment and affects the overhaul period.

[0134] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0135] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A boric acid solution recovery system for a nuclear power plant, characterized in that, Comprising: A front storage tank, with one end connected to the primary loop of the reactor and the other end sequentially connected to an intermediate storage tank, an evaporator, a boric acid storage tank, and a refueling water tank; The intermediate storage tanks are at least 3 in parallel; A two-way boron transfer pipeline is provided between the intermediate storage tank and the refueling water tank; The reactor pool, the component pool, and the loading well are respectively connected to the refueling water tank.

2. The boric acid solution recovery system for nuclear power plants according to claim 1, wherein The two-way boron transfer pipeline includes three branches; Both ends of the first branch are the intermediate storage tank and the refueling water tank respectively; A first valve, a second valve, a boron transfer pump, a third valve, and a fourth valve are sequentially arranged on the first branch; One end of the second branch is connected between the first valve and the second valve, and the other end is connected to the outlet end of the boron transfer pump; a fifth valve is arranged on the second branch; One end of the third branch is connected to the inlet end of the boron transfer pump, and the other end is connected between the third valve and the fourth valve; a sixth valve is arranged on the third branch.

3. The boric acid solution recovery system for nuclear power plants according to claim 1, characterized in that A detachable air lock is installed between the reactor pool and the component pool.

4. A method for recycling boric acid solution in a nuclear power plant, characterized in that, Comprising: Recovery of the boric acid solution discharged from the primary loop of the reactor and recovery of the boric acid solution in the refueling water tank; The recovery of the boric acid solution discharged from the primary loop of the reactor is specifically as follows: Judge the concentration of the boric acid solution discharged from the primary loop of the reactor. If it is less than 2400 ppm, the discharged boric acid solution is concentrated to 2400 ppm in the evaporator and then stored in the boric acid storage tank until the refueling water tank is available and then transferred to the refueling water tank; If the concentration of the boric acid solution discharged from the primary loop of the reactor is equal to 2400 ppm, the discharged boric acid solution is stored in any two intermediate storage tanks with sufficient capacity until the refueling water tank is available and then transferred to the refueling water tank; The recovery of the boric acid solution in the refueling water tank is specifically as follows: Before discharging the fuel, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool and the component pool until the reactor pool and the component pool are full; After discharging the fuel from the reactor, only the boric acid solution in the reactor pool is transferred back to the refueling water tank; Before the refueling water tank is overhauled, a part of the boric acid solution in the refueling water tank is transferred to any two intermediate storage tanks with sufficient capacity through the two-way boron transfer pipeline until the two intermediate storage tanks are full, and the remaining boric acid solution in the refueling water tank is transferred to the loading well; After the refueling water tank is overhauled, the boric acid solution in the intermediate storage tank is transferred back to the refueling water tank through the two-way boron transfer pipeline; Transfer the boric acid solution in the loading well back to the refueling water tank; Before loading the reactor, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool until the reactor pool is full; After loading the reactor, the boric acid solution in the reactor pool and the component pool is transferred back to the refueling water tank.

5. The method for recycling boric acid solution in a nuclear power plant according to claim 4, wherein, The working conditions where the concentration of the boric acid solution discharged from the primary loop of the reactor is less than 2400 ppm include: the period from when the concentration of the boric acid solution discharged from the primary loop of the reactor is less than 2400 ppm during the reactor startup process to when the concentration of the boric acid discharged from the primary loop of the reactor reaches 2400 ppm before the reactor shutdown process; The working conditions where the concentration of the boric acid solution discharged from the primary loop of the reactor is equal to 2400 ppm include: the period from when the concentration of the boric acid solution discharged from the primary loop of the reactor reaches 2400 ppm during the reactor shutdown process to when the concentration of the boric acid solution discharged from the primary loop of the reactor is less than 2400 ppm before the reactor startup process.

6. The method for recycling boric acid solution in a nuclear power plant according to claim 4, wherein, After the reactor is discharged, an air lock is installed between the reactor pool and the component pool. The boric acid solution in the component pool does not flow back to the refueling water tank, and only the boric acid solution in the reactor pool flows back to the refueling water tank.

7. The method for recycling boric acid solution in a nuclear power plant according to claim 6, characterized in that, Before the reactor is loaded, a part of the boric acid solution in the refueling water tank is transferred to the reactor pool until the reactor pool is full, and the air lock between the reactor pool and the component pool is removed.

8. The method for recycling boric acid solution in a nuclear power plant according to claim 4, characterized in that, When recovering the boric acid solution discharged from the primary circuit of the reactor; If the concentration of the boric acid solution discharged from the primary circuit of the reactor is equal to 2400 ppm, the discharged boric acid solution is stored in any two intermediate storage tanks with sufficient capacity; When the refueling water tank does not need to be repaired, the boric acid solution is directly transferred to the refueling water tank through the two-way boron transfer pipeline; When the refueling water tank needs to be repaired, after the repair of the refueling water tank is completed, the boric acid solution is transferred to the refueling water tank through the two-way boron transfer pipeline.

9. The method for recycling boric acid solution in a nuclear power plant according to claim 8, wherein, When recovering the boric acid solution in the refueling water tank, before the refueling water tank is repaired, a part of the boric acid solution in the refueling water tank is transferred to any two intermediate storage tanks with sufficient capacity through the two-way boron transfer pipeline; The operation method of the two-way boron transfer pipeline is as follows: The first valve, the fourth valve, the fifth valve and the sixth valve are opened; the second valve and the third valve are closed, and the boron transfer pump is started.

10. The method for recycling boric acid solution in a nuclear power plant according to claim 8, wherein When recovering the boric acid solution in the refueling water tank, after the refueling water tank is repaired, the boric acid solution in the intermediate storage tank is transferred back to the refueling water tank through the two-way boron transfer pipeline. The operation method of the two-way boron transfer pipeline is as follows: The first valve, the second valve, the third valve and the fourth valve are opened; the fifth valve and the sixth valve are closed, and the boron transfer pump is started.

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