Pressurized water reactor nuclear power station decontamination waste liquid treatment system and method

Abstract

The invention relates to the technical field of pressurized water reactor nuclear power station primary loop chemical decontamination waste water treatment, in particular to a pressurized water reactor nuclear power station decontamination waste liquid treatment system and method. The system adopts a combined process of pre-oxidation and electron beam irradiation, can effectively remove organic matters in the organic waste liquid, greatly improves the degradation efficiency of the waste liquid, reduces the chemical oxygen demand, and ensures that the treated waste liquid meets the waste liquid discharge standard of a nuclear power station. And secondly, the heat exchange tube structure arranged in the reactor can quickly and uniformly increase the temperature of the waste liquid through an external high-temperature molten salt heating mode, so that the requirement of the oxidation reaction on the temperature is met, and the treatment efficiency is improved. Through automatic control and intelligent feedback adjustment, the adding amount of the oxidizing agent, the pH value of the waste liquid and the treatment conditions can be accurately controlled, errors caused by manual operation are remarkably reduced, and the stability and safety of system operation are improved.

Description

Technical Field

[0001] The invention relates to the technical field of primary-loop chemical decontamination wastewater treatment in a pressurized water reactor nuclear power plant, in particular to a system and method for treating decontamination wastewater in a pressurized water reactor nuclear power plant. Background Art

[0002] During the maintenance of a pressurized water reactor nuclear power plant unit, in order to carry out equipment maintenance work, it is necessary to isolate the radioactive hot spots in the system and equipment. If the existence of hot spots affects the maintenance work, appropriate radioactive decontamination work needs to be carried out. Chemical decontamination is one of the methods.

[0003] Chemical decontamination uses the dissolving and stripping effects of chemical reagents to remove radioactive activated corrosion products deposited in the pipeline. The detergents used in chemical decontamination generally contain organic substances such as oxalic acid, formic acid, citric acid, and EDTA. After the chemical decontaminants are used, they are generally discharged into the radioactive waste liquid treatment system of the nuclear power plant, and then cement solidification is carried out after evaporation and concentration. The presence of organic matter may affect the stability of the cement solidified body. Therefore, it is necessary to explain the COD in the organic decontaminant before the cement solidification treatment to eliminate the potential impact on the cement solidified body.

[0004] At present, the commonly used organic waste liquid degradation technology is mainly wet oxidation process, including Fenton oxidation, UV-Fenton oxidation, O3 oxidation, O3 / UV oxidation, etc. In the implementation of the above wet oxidation process, oxidants such as H2O2 and O3 need to be used. In order to achieve a deep degradation effect, it is generally necessary to maintain a high oxidant concentration, which will lead to a more violent reaction and will be accompanied by a strong gas release process (mainly H2O2 and O3 self-decomposition), affecting the safety of the operation. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the first purpose of the present invention is to propose a PWR nuclear power plant decontamination waste liquid treatment system that can solve the problems of low treatment efficiency and low operational safety during the degradation of organic waste liquid used in the primary chemical decontamination of a PWR nuclear power plant.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant, comprising a degradation component, including a waste liquid tank, an oxidant tank, a mixing tank, a reactor, and a neutralization tank, wherein the waste liquid tank is connected to the mixing tank through a first pipe, the oxidant tank is connected to the middle part of the first pipe through a second pipe, the mixing tank is connected to the reactor through a third pipe, and the reactor is connected to the neutralization tank through a fourth pipe; the neutralization tank is provided with a fifth pipe and a sixth pipe, the fifth pipe is connected to the original wastewater treatment system, and one end of the sixth pipe is connected to the fifth pipe, and the other end is connected to the mixing tank.

[0008] As a preferred solution of the decontamination waste liquid treatment system of a pressurized water reactor nuclear power plant described in the present invention, wherein: a dosing pump, a first valve, and a second valve are arranged on the first pipeline, the dosing pump is arranged between the access end of the second pipeline and the access end of the mixing tank, the first valve is arranged between the waste liquid tank and the access end of the second pipeline, and the second valve is arranged between the dosing pump and the mixing tank; a third valve is arranged on the second pipeline.

[0009] As a preferred solution of the pressurized water reactor nuclear power plant decontamination waste liquid treatment system of the present invention, the third pipeline is provided with a fourth valve, a circulation pump, and a fifth valve, and the fourth valve and the fifth valve are respectively arranged on both sides of the circulation pump.

[0010] As a preferred solution of the decontamination waste liquid treatment system of the pressurized water reactor nuclear power plant of the present invention, wherein: an electron beam processor and a COD tester are arranged on the fourth pipeline, and the electron beam processor is arranged between the reactor and the COD tester.

[0011] As a preferred solution of the decontamination waste liquid treatment system of the pressurized water reactor nuclear power plant described in the present invention, the fifth pipeline is provided with a sixth valve, a waste liquid pump and a seventh valve, the waste liquid pump is provided between the neutralization tank and the access end of the sixth pipeline, the seventh valve is provided between the access end of the sixth pipeline and the original wastewater treatment system; the sixth pipeline is provided with an eighth valve.

[0012] As a preferred solution of the decontamination waste liquid treatment system of the pressurized water reactor nuclear power plant of the present invention, the degradation component is also provided with an alkali tank, the alkali tank is connected to the neutralization tank through a seventh pipeline, and the seventh pipeline is also provided with an alkali adding pump; the neutralization tank is also provided with a pH meter.

[0013] As a preferred solution of the decontamination waste liquid treatment system of the pressurized water reactor nuclear power plant described in the present invention, the waste liquid tank, oxidant tank, mixing tank, reactor, neutralization tank, alkali tank and the connected pipes, valves and pumps are all made of austenitic stainless steel with a material grade not lower than 304L.

[0014] As a preferred solution of the decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant of the present invention, a heat exchange tube is arranged in the reactor, and the outside of the heat exchange tube is filled with high-temperature molten salt.

[0015] Another object of the present invention is to provide a method for treating decontaminated waste liquid in a pressurized water reactor nuclear power plant, which comprises the following steps: opening a first valve, a second valve and a third valve, pumping the organic waste liquid in the waste liquid tank and the oxidant liquid in the oxidant tank into a mixing tank through a dosing pump for thorough mixing; opening a fourth valve and a fifth valve, and pumping the mixed solution in the mixing tank into a reactor by a circulating pump for pre-oxidation treatment; the waste liquid after pre-oxidation treatment is subjected to deep treatment by an electron beam processor, and the waste liquid after electron beam treatment is tested by a COD tester; the waste liquid after the test is subjected to deep treatment by an electron beam processor, and the waste liquid after electron beam treatment is tested by a COD tester; the waste liquid after the test is subjected to deep treatment by an electron beam processor, and the waste liquid after the test is subjected to deep treatment by a COD tester, and the waste liquid after the test is subjected to deep treatment by an electron beam processor, and the waste liquid after the test is subjected to deep treatment by a ... electron beam processor, and the waste liquid after the test is subjected to deep treatment by The liquid enters the neutralization tank for neutralization treatment. The waste liquid in the neutralization tank is tested by an online pH meter. If the value is low, the alkali liquid in the alkali tank is pumped into the neutralization tank through an alkali pump to adjust the value in the neutralization tank to 6-9; when the test is less than 500mg / L, the sixth valve and the seventh valve are opened to pump the waste liquid in the neutralization tank into the original wastewater treatment system using the waste liquid pump. If it is greater than or equal to 500mg / L, the sixth valve and the eighth valve are opened to pump the waste liquid back to the mixing tank through the waste liquid pump, and the oxidant is added again for treatment until the wastewater content meets the requirements;.

[0016] As a preferred solution of the method for treating decontamination waste liquid of a pressurized water reactor nuclear power plant of the present invention, the oxidant added to the oxidant tank is an ammonium persulfate solution with a concentration of 20% to 40%.

[0017] The beneficial effects of the present invention are as follows: the system adopts a combined process of pre-oxidation and electron beam irradiation, which can effectively remove organic matter in organic waste liquid, greatly improve the degradation efficiency of waste liquid, and reduce the chemical oxygen demand (COD), ensuring that the waste liquid meets the nuclear power plant waste liquid discharge standards after treatment. Secondly, the heat exchange tube structure arranged inside the reactor can quickly and evenly increase the temperature of the waste liquid through the external high-temperature molten salt heating method, meet the temperature requirements of the oxidation reaction, and improve the processing efficiency. Through automatic control and intelligent feedback regulation, the amount of oxidant added, the pH value of the waste liquid and the processing conditions can be accurately controlled, which significantly reduces the errors of manual operation and improves the stability and safety of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0019] Figure 1 This is a schematic diagram of the decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant.

[0020] Figure 2 A step-by-step diagram of a method for treating waste liquid from a pressurized water reactor nuclear power plant. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0024] Example 1

[0025] Reference Figure 1 , which is the first embodiment of the present invention, and provides a decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant includes a degradation component 100, including a waste liquid tank 101, an oxidant tank 102, a mixing tank 103, a reactor 104, and a neutralization tank 105. The waste liquid tank 101 is connected to the mixing tank 103 through a first pipe 201, the oxidant tank 102 is connected to the middle of the first pipe 201 through a second pipe 202, the mixing tank 103 is connected to the reactor 104 through a third pipe 203, and the reactor 104 is connected to the neutralization tank 105 through a fourth pipe 204; the neutralization tank 105 is provided with a fifth pipe 205 and a sixth pipe 206, the fifth pipe 205 is connected to the original wastewater treatment system, and one end of the sixth pipe 206 is connected to the fifth pipe 205, and the other end is connected to the mixing tank 103.

[0026] The waste liquid tank 101 is used to store waste liquid from the chemical decontamination process of the pressurized water reactor nuclear power plant; the oxidant tank 102 stores the oxidant used to oxidize the organic matter in the waste liquid, which can fully react with the waste liquid and decompose the organic matter therein; the mixing tank 103 injects the waste liquid and the oxidant into the mixing tank through the dosing pump for uniform mixing, ensuring that the two are fully mixed before entering the reactor 104 to improve the efficiency of the oxidation reaction; the reactor 104 is used for the oxidation reaction of the waste liquid. At this stage, the waste liquid will undergo high-temperature oxidation treatment; the neutralization tank 105 is used to adjust the pH value of the waste liquid. The waste liquid may have strong acidity after treatment, so neutralization operation is required to ensure that the waste liquid meets environmental protection requirements before discharge. The fifth pipeline 205 and the sixth pipeline 206 are respectively used to connect the neutralized waste liquid to the original wastewater treatment system, or return to the mixing tank for re-treatment when the treatment is unqualified.

[0027] Example 2

[0028] Reference Figure 1-2 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0029] Specifically, the first pipeline 201 is provided with a dosing pump 201a, a first valve 201b, and a second valve 201c. The dosing pump 201a is provided between the access end of the second pipeline 202 and the access end of the mixing tank 103. The first valve 201b is provided between the waste liquid tank 101 and the access end of the second pipeline 202. The second valve 201c is provided between the dosing pump 201a and the mixing tank 103. The second pipeline 202 is provided with a third valve 202a.

[0030] The dosing pump 201a ensures that the waste liquid and the oxidant are injected into the mixing tank 103 in proportion to maintain the consistency and efficiency of the treatment. The dosing pump can accurately control the flow rate to ensure the full mixing of the waste liquid and the oxidant; the first valve 201b is used to control the waste liquid delivery process between the waste liquid tank and the mixing tank, and can control the waste liquid flow rate according to actual conditions; the second valve 201c is used for flow control between the dosing pump 201a and the mixing tank 103 to prevent excessive delivery during the dosing process and ensure the accuracy of the reaction. The third valve 202a controls the flow of the oxidant. The existence of this valve ensures that the delivery amount of the oxidant is synchronized with the flow rate of the waste liquid to avoid excessive or insufficient reaction.

[0031] Specifically, the third pipeline 203 is provided with a fourth valve 203a, a circulation pump 203b, and a fifth valve 203c, and the fourth valve 203a and the fifth valve 203c are respectively provided on both sides of the circulation pump 203b;

[0032] The fourth valve 203a and the fifth valve 203c are used to control the flow of the waste liquid. Through these two valves, the flow rate of the waste liquid entering the reactor 104 can be effectively adjusted to ensure that the waste liquid can fully contact the oxidant in the reactor and reach an appropriate reaction time; the circulation pump 203b is used to transport the waste liquid in the mixing tank to the reactor 104, ensuring the continuity and stability of the waste liquid flow and ensuring the stable operation of the system.

[0033] Specifically, the fourth pipeline 204 is provided with an electron beam processor 204a and a COD tester 204b, and the electron beam processor 204a is provided between the reactor 104 and the COD tester 204b;

[0034] The electron beam processor 204 is used to further degrade organic matter in the waste liquid. Its specific dosage is adjusted according to the organic matter concentration of the waste liquid. Through electron beam irradiation, the chemical bonds of organic matter can be effectively broken, further improving the processing efficiency; the COD tester 204b is used to monitor the chemical oxygen demand (COD) in the waste liquid in real time to determine the degree of removal of organic matter in the waste liquid. If the COD does not meet the set standard, the waste liquid will be returned to the system for secondary treatment.

[0035] Specifically, the fifth pipeline 205 is provided with a sixth valve 205a, a waste liquid pump 205b and a seventh valve 205c, the waste liquid pump 205b is provided between the neutralization tank 105 and the access end of the sixth pipeline 206, and the seventh valve 205c is provided between the access end of the sixth pipeline 206 and the original wastewater treatment system; the sixth pipeline 206 is provided with an eighth valve 206a;

[0036] The seventh valve 205c and the eighth valve 206a are used to control the flow path of the waste liquid to ensure flow control in different treatment stages; the waste liquid pump 205b is used to transport the neutralized waste liquid to the next treatment link to ensure that the neutralized waste liquid can enter the original wastewater treatment system.

[0037] Specifically, the degradation component 100 is further provided with an alkali tank 106, which is connected to the neutralization tank 105 through a seventh pipeline 207, and an alkali pump 207a is further provided on the seventh pipeline 207; and a pH meter 105a is further provided in the neutralization tank 105;

[0038] The alkali tank 106 is used to store alkaline solution (such as sodium hydroxide solution), which will be used for neutralization treatment in the final stage of waste liquid treatment to adjust the pH value of the waste liquid and ensure that the discharged waste liquid meets environmental standards; the alkali pump 207a is used to accurately control the injection amount of the alkali solution to ensure that it can be automatically adjusted as needed to avoid excessive or insufficient conditions; the pH meter 105a is an online pH meter used to monitor the pH value of the waste liquid in the neutralization tank 105 in real time. According to the reading of the pH meter, the system automatically adjusts the workload of the alkali pump 207a to ensure that the pH value of the waste liquid is maintained between 6 and 9. Too high or too low a pH value may affect the compliance of waste liquid discharge, so real-time monitoring and adjustment are required.

[0039] Specifically, the waste liquid tank 101, the oxidant tank 102, the mixing tank 103, the reactor 104, the neutralization tank 105, the alkali tank 106 and the connected pipes, valves and pumps are all made of austenitic stainless steel, and the material grade is not less than 304L;

[0040] Austenitic stainless steel is a material with excellent corrosion resistance and high temperature resistance, and is particularly suitable for treating corrosive substances such as organic acids and oxidants contained in chemical decontamination wastewater. Using austenitic stainless steel as the main material can not only effectively prevent equipment corrosion and extend service life, but also ensure long-term stable operation of the system in high temperature and strong acid and alkali environments. Choosing 304L stainless steel, which has a lower carbon content, can prevent intergranular corrosion and improve the corrosion resistance of the material.

[0041] Specifically, the reactor 104 is provided with a heat exchange tube 104a, and the outside of the heat exchange tube 104a is filled with high-temperature molten salt 104b to meet the temperature requirement of the oxidation reaction;

[0042] The heat exchange tube 104a is used to heat the waste liquid to the required oxidation reaction temperature. Generally, the organic pollutants in the waste liquid need to react effectively with the oxidant at a higher temperature (about 150°C). As a heat exchange medium, the high-temperature molten salt 104b has excellent thermal conductivity and can quickly transfer heat to the waste liquid in the heat exchange tube. The high-temperature molten salt in this embodiment adopts a sodium nitrate / potassium nitrate mixture, which can maintain stability at high temperatures and is not easy to volatilize. The use of molten salt ensures that the waste liquid can maintain a constant temperature to meet the temperature requirements of the oxidation reaction.

[0043] Example 3

[0044] Reference Figure 1-2 , which is the third embodiment of the present invention, and provides a method for treating decontamination waste liquid in a pressurized water reactor nuclear power plant, comprising opening a first valve 201b, a second valve 201c and a third valve 202a, pumping the organic waste liquid in the waste liquid tank 101 and the oxidant liquid in the oxidant tank 102 into a mixing tank 103 through a dosing pump 201a for thorough mixing;

[0045] The fourth valve 203a and the fifth valve 203c are opened, and the circulating pump 203b pumps the mixed solution in the mixing tank 103 into the reactor 104 for pre-oxidation treatment;

[0046] The waste liquid after the pre-oxidation treatment is further treated by the electron beam processor 204a, and the waste liquid treated by the electron beam is then tested by the COD tester 204b for COD;

[0047] The waste liquid after the test enters the neutralization tank 105 for neutralization treatment. The waste liquid in the neutralization tank 105 is tested for pH value by the pH meter 105a. If the pH value is low, the alkali liquid in the alkali tank 106 is pumped into the neutralization tank 105 through the alkali pump 207a to adjust the pH value in the neutralization tank 105 to 6-9.

[0048] When the COD test is less than 500 mg / L, the sixth valve 205a and the seventh valve 205c are opened to pump the waste liquid in the neutralization tank 105 into the original wastewater treatment system by the waste liquid pump 205b. If the COD is greater than or equal to 500 mg / L, the sixth valve 205a and the eighth valve 206a are opened to pump the waste liquid back to the mixing tank 103 by the waste liquid pump 205b, and the oxidant is added again for treatment until the COD content of the wastewater meets the requirements;

[0049] The valves can be set as electric valves, through the operation of these valves, the system can achieve automatic or manual flow control.

[0050] Specifically, the oxidant added to the oxidant tank 102 is an ammonium persulfate solution with a concentration of 20% to 40%;

[0051] Ammonium persulfate is a strong oxidant that can effectively oxidize organic matter in wastewater. According to experimental data, within the concentration range of 20%-40%, ammonium persulfate can maximize its oxidizing ability while avoiding safety hazards caused by excessive concentration; the selection of electron beam irradiation dose is based on the concentration of organic matter in the wastewater. Low-concentration organic wastewater can be treated with a lower dose (about 1 kGy), while high-concentration organic wastewater requires a higher dose.

[0052] When in use, 50L of citric acid-EDTA decontamination waste liquid with a concentration of about 2% is loaded into the waste liquid tank 101, and 100L of 30% ammonium persulfate solution is loaded into the oxidant tank 102. The decontamination waste liquid and the ammonium persulfate solution are pumped into the mixing tank 103 through the dosing pump 201a in a volume ratio of not less than 3:5, and the molten salt temperature in the reactor 104 is adjusted to 150°C, and the circulation pump 203b is started to pump the solution in the mixing tank 103 into the reactor 104 for pre-oxidation treatment, and the opening of the fifth valve 203c is adjusted to control the outlet solution temperature of the reactor 104 to be not less than 100°C; adjust the electron beam processor 2 04a electron beam irradiation dose to an appropriate dose, the waste liquid is deeply treated; the COD of the waste liquid is tested by a COD tester 204b, and the test result is 1500mg / L; after the waste liquid enters the neutralization tank 105, the waste liquid is tested by an online pH meter 105a and the pH value is 2.5, and the alkali liquid in the alkali tank 106 is pumped into the neutralization tank 105 by an alkali pump 207a, and the pH value in the neutralization tank 105 is adjusted to 8; because the COD does not meet the requirement of 500mg / L, the waste liquid is pumped back to the mixing tank 103 by a waste liquid pump 205b, and ammonium persulfate is added again for treatment until the COD meets the requirement.

[0053] Table 1 shows the COD test results of 1.5% citric acid + 0.5% EDTA solution before and after 30% persulfate ammonium oxidation (volume ratio 3:5)

[0054]

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant, characterized in that: include, A degradation component (100) comprises a waste liquid tank (101), an oxidant tank (102), a mixing tank (103), a reactor (104), and a neutralization tank (105), wherein the waste liquid tank (101) is connected to the mixing tank (103) via a first pipeline (201), the oxidant tank (102) is connected to the middle of the first pipeline (201) via a second pipeline (202), the mixing tank (103) is connected to the reactor (104) via a third pipeline (203), and the reactor (104) is connected to the neutralization tank (105) via a fourth pipeline (204); The neutralization tank (105) is provided with a fifth pipeline (205) and a sixth pipeline (206), wherein the fifth pipeline (205) is connected to the original wastewater treatment system, and the sixth pipeline (206) is connected to the fifth pipeline (205) at one end and connected to the mixing tank (103) at the other end.

2. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 1, characterized in that: The first pipeline (201) is provided with a dosing pump (201a), a first valve (201b), and a second valve (201c); the dosing pump (201a) is arranged between the access end of the second pipeline (202) and the access end of the mixing tank (103); the first valve (201b) is arranged between the waste liquid tank (101) and the access end of the second pipeline (202); and the second valve (201c) is arranged between the dosing pump (201a) and the mixing tank (103); The second pipeline (202) is provided with a third valve (202a).

3. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 2, characterized in that: The third pipeline (203) is provided with a fourth valve (203a), a circulation pump (203b), and a fifth valve (203c), and the fourth valve (203a) and the fifth valve (203c) are respectively arranged on both sides of the circulation pump (203b).

4. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 3, characterized in that: The fourth pipeline (204) is provided with an electron beam processor (204a) and a COD tester (204b), and the electron beam processor (204a) is arranged between the reactor (104) and the COD tester (204b).

5. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 4, characterized in that: The fifth pipeline (205) is provided with a sixth valve (205a), a waste liquid pump (205b) and a seventh valve (205c); the waste liquid pump (205b) is provided between the neutralization tank (105) and the access end of the sixth pipeline (206); and the seventh valve (205c) is provided between the access end of the sixth pipeline (206) and the original wastewater treatment system; The sixth pipeline (206) is provided with an eighth valve (206a).

6. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 5, characterized in that: The degradation component (100) is further provided with an alkali tank (106), and the alkali tank (106) is connected to the neutralization tank (105) via a seventh pipeline (207), and an alkali pump (207a) is further provided on the seventh pipeline (207); The neutralization tank (105) is also provided with a pH meter (105a).

7. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 6, characterized in that: The waste liquid tank (101), oxidant tank (102), mixing tank (103), reactor (104), neutralization tank (105), alkali tank (106) and the connected pipes, valves and pumps are all made of austenitic stainless steel with a material grade not less than 304L.

8. The decontamination waste liquid treatment system for a pressurized water reactor nuclear power plant according to claim 7, characterized in that: A heat exchange tube (104a) is provided in the reactor (104), and the exterior of the heat exchange tube (104a) is filled with high-temperature molten salt (104b).

9. A method for treating waste liquid from a pressurized water reactor nuclear power plant, characterized in that: The method for treating decontamination waste liquid from a pressurized water reactor nuclear power plant comprises: Open the first valve (201b), the second valve (201c) and the third valve (202a), and pump the organic waste liquid in the waste liquid tank (101) and the oxidant liquid in the oxidant tank (102) into the mixing tank (103) through the dosing pump (201a) for thorough mixing; The fourth valve (203a) and the fifth valve (203c) are opened, and the circulating pump (203b) pumps the mixed solution in the mixing tank (103) into the reactor (104) for pre-oxidation treatment; The waste liquid after the pre-oxidation treatment is further treated by an electron beam processor (204a), and the waste liquid treated by the electron beam is then tested for COD by a COD tester (204b); The waste liquid after the test enters the neutralization tank (105) for neutralization treatment. The pH value of the waste liquid in the neutralization tank (105) is tested by a pH meter (105a). If the pH value is low, the alkali liquid in the alkali tank (106) is pumped into the neutralization tank (105) through an alkali pump (207a) to adjust the pH value in the neutralization tank (105) to 6 to 9; When the COD test result is less than 500 mg / L, the sixth valve (205a) and the seventh valve (205c) are opened to pump the waste liquid in the neutralization tank (105) into the original wastewater treatment system using the waste liquid pump (205b). If the COD is greater than or equal to 500 mg / L, the sixth valve (205a) and the eighth valve (206a) are opened to pump the waste liquid back into the mixing tank (103) through the waste liquid pump (205b), and the oxidant is added again for treatment until the COD content of the wastewater meets the requirements.

10. The method for treating waste liquid from a pressurized water reactor nuclear power plant according to claim 9, characterized in that: The oxidant added to the oxidant tank (102) is an ammonium persulfate solution with a concentration of 20% to 40%.

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