Corrosion test method for simulated feedwater of evaporator for radioactive feedwater

Abstract

The application discloses a corrosion test method for simulating a radioactive feed liquid of an evaporator, and comprises the following steps: 1) selecting a first material with corrosion performance suitable for an operating environment of the evaporator by using a simulated feed liquid in a quick screening test, wherein vanadium ions are used in the simulated feed liquid to simulate plutonium ions in the radioactive feed liquid; 2) selecting a second material by performing a corrosion test on the first material, wherein the simulated feed liquid is used in the corrosion test; 3) selecting a simulated evaporator product by performing a corrosion body test on the second material, wherein the second material is processed into the simulated evaporator, the simulated feed liquid is used in the corrosion body test to simulate operation of the radioactive feed liquid in the evaporator in the simulated evaporator. The method is reasonable and effective in determining the corrosion resistance of a material of a plutonium-containing evaporator, plays a guiding role in research and operation of the plutonium-containing evaporator, and is good in simulation and strong in operability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear fuel reprocessing, and particularly relates to a corrosion test method of simulated feed liquid for an evaporator of radioactive feed liquid. BACKGROUND

[0002] The nuclear fuel reprocessing plant mainly adopts the PUREX process, and the reflux extraction method is mainly used in the plutonium purification process to concentrate plutonium. In the plutonium tail end process, the plutonium nitrate solution is converted into plutonium dioxide powder by the method of plutonium oxalate precipitation-filtration-roasting. A small amount of plutonium is contained in the filtrate mother liquor during the precipitation-filtration process, which needs to be recovered. The oxalic acid in the mother liquor needs to be destroyed during the recovery and utilization.

[0003] The introduction of the evaporator containing plutonium feed liquid in the plutonium purification process can greatly improve the concentration efficiency of plutonium, reduce the amount of waste liquid, and reduce the time and cost of plant operation. Similarly, since the amount of plutonium in the filtrate mother liquor is very small, the use of the evaporator to evaporate and concentrate the mother liquor before returning to the system can greatly reduce the processing load of the system, reduce the amount of reagents and radioactive waste liquid additionally increased by concentrating the feed liquid in the previous process, meet the principle of waste minimization of the reprocessing plant, and improve the operating flux of the plant, which has strong economic efficiency.

[0004] At present, the technology of the plutonium-containing evaporator has not been mastered. One of the main reasons is that the operating environment is special, involving high temperature, cold and hot alternation and other working conditions, and the corrosion of the equipment material is strong. In addition, the plutonium feed liquid itself is corrosive, and the additional oxalic acid and nitric acid can also cause corrosion to the equipment. Therefore, the corrosion resistance of the plutonium-containing evaporator material needs to be studied.

[0005] At the same time, due to the strict management of plutonium, as well as the extreme toxicity and radioactivity of plutonium, it is impossible to carry out research and test work on the plutonium-containing evaporator using real plutonium feed liquid. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a corrosion test method of simulated feed liquid for an evaporator of radioactive feed liquid, which can solve the above problems in the prior art. The simulated feed liquid with good simulation and strong operability is used to carry out research work on the plutonium-containing evaporator, and technical support is provided for the design and operation of the evaporator for the radioactive feed liquid containing plutonium.

[0007] The present application provides a simulated feed liquid preparation method, basic composition and corrosion test method of a typical radioactive feed liquid containing plutonium concentration evaporator and radioactive mother liquor evaporator.

[0008] The technical solution adopted to solve the technical problem of the present application is to provide a corrosion test method of simulated feed liquid for an evaporator of radioactive feed liquid, comprising the following steps:

[0009] 1) selecting a first material with suitable corrosion performance for the operating environment of the evaporator by using a simulated feed solution in a quick screening test, the simulated feed solution using vanadium ions to simulate plutonium ions in the radioactive feed solution;

[0010] 2) selecting a second material by conducting a corrosion test on the first material using a simulated feed solution;

[0011] 3) selecting a simulated evaporator product by conducting a corrosion body test on the second material, the corrosion body test referring to processing the second material into a simulated evaporator, and using a simulated feed solution to simulate the operation of the radioactive feed solution in the evaporator in the simulated evaporator.

[0012] Preferably, when the evaporator is used for the concentration of a plutonium-containing radioactive feed solution, the plutonium-containing radioactive feed solution does not include a radioactive mother liquor, the plutonium-containing radioactive feed solution includes plutonium ions and fission elements, the plutonium-containing radioactive feed solution is a nitric acid system, and the concentration of the plutonium ions is 4.1×10 -3 ~ 1.67 mol / L.

[0013] Preferably, the minimum value of the concentration of vanadium ions in the simulated feed solution is not less than the concentration of plutonium in the plutonium-containing radioactive feed solution in the initial state of the evaporator when the evaporator is used for the concentration of plutonium, and the maximum value of the concentration of vanadium ions is not more than three times the concentration of plutonium in the plutonium-containing radioactive feed solution after the concentration.

[0014] Preferably, the non-radioactive reagents in the simulated feed solution remain consistent with the plutonium-containing radioactive feed solution in the initial state;

[0015] Preferably, the concentration of nitric acid in the simulated feed solution is 0.5 ~ 16 mol / L, and the concentration of fission elements in the simulated feed solution is less than 10 -3 ~ 10 -6 mol / L.

[0016] Preferably, the radioactive feed solution is a radioactive mother liquor, when the evaporator is used for the evaporation of the radioactive mother liquor, the radioactive mother liquor includes plutonium ions and metal ions, the radioactive mother liquor is an oxalic acid system or a nitric acid system, and the concentration of the plutonium ions is 4.1×10 -6 ~ 8.4×10 -2 mol / L.

[0017] Preferably, the radioactive feed solution is a radioactive mother liquor,

[0018] The minimum value of the concentration of vanadium ions in the simulated feed solution is not less than the concentration of plutonium in the radioactive mother liquor in the initial state of the evaporator, and the maximum value of the concentration of vanadium ions is not more than three times the concentration of plutonium in the plutonium-containing radioactive feed solution after the concentration.

[0019] Preferably, the metal ions in the radioactive mother liquor remain consistent with the radioactive mother liquor in the initial state;

[0020] The concentration of nitric acid in the simulated feed solution is 0.5-16 mol / L,

[0021] The concentration of oxalic acid in the simulated feed solution is consistent with that of the radioactive mother liquor,

[0022] The concentration of the fissile element in the simulated feed solution is less than 10 -3 6 mol / L.

[0023] Preferably, the temperature at which the simulated feed solution in step 3) is operated in the simulated evaporator is 20-140℃, and the pressure is -15-2 kPa.

[0024] Preferably, in step 1), the quick screening test comprises a first electrochemical corrosion test and a first uniform corrosion test.

[0025] Preferably, in step 1), the test conditions of the quick screening test are the highest temperature in the preset temperature range of the quick screening and the maximum pressure in the preset pressure range of the quick screening.

[0026] Preferably, in step 1), the test conditions of the quick screening test are the ratio of the most corrosive corrosion solution in the preset corrosion range and the maximum concentration of each component in the preset concentration range of the simulated feed solution.

[0027] Preferably, in step 2), the corrosion test comprises a second electrochemical corrosion test, a second uniform corrosion test, and a localized corrosion test.

[0028] Preferably, in step 2), the test conditions of the corrosion test are the highest temperature and the lowest temperature in the preset temperature range of the corrosion, and the maximum pressure and the minimum pressure in the preset pressure range of the corrosion.

[0029] Preferably, the concentration of the simulated feed solution comprises any one or several of the maximum vanadium ion concentration, nitric acid concentration, non-radioactive reagent concentration, manganese ion concentration, potassium permanganate concentration, and oxalic acid concentration in the preset concentration range;

[0030] and any one or several of the minimum vanadium ion concentration, nitric acid concentration, non-radioactive reagent concentration, manganese ion concentration, potassium permanganate concentration, and oxalic acid concentration.

[0031] Preferably, the simulated evaporator in step 3) comprises a simulated evaporator tank body and a welded joint provided on the simulated evaporator tank body.

[0032] Preferably, the simulated evaporator in step 3) has an outer size not greater than that of the evaporator, the internal component structure and type of the simulated evaporator are consistent with those of the plutonium-containing evaporator, and the number of internal components of the simulated evaporator is 1-2. ​

[0033] Preferably, the test time of the corrosion body test in step 3) is not less than 1 month.

[0034] The method in the present application proposes a simulation liquid preparation method and a composition ratio of the simulation liquid for a plutonium-containing evaporator, which has good simulation and strong operability, and a test method for rapidly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and has strong operability.

[0035] The corrosion test method for the simulation liquid of the evaporator for radioactive liquid in the present application has the following beneficial effects:

[0036] (1) A simulation liquid preparation and corrosion test method for a plutonium-containing evaporator in a reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0037] (2) A simulation liquid preparation method for a plutonium-containing evaporator in a reprocessing plant is determined, which has good simulation and strong operability;

[0038] (3) A corrosion test method for a plutonium-containing evaporator is provided, which includes the composition of the simulation liquid for the test, the test conditions, and the test content. The test method is simple, reasonable, and economical. DETAILED DESCRIPTION

[0039] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below in combination with specific embodiments.

[0040] Embodiment 1

[0041] The present embodiment provides a corrosion test method for a simulation liquid of an evaporator for radioactive liquid, which comprises the following steps:

[0042] 1) For at least two samples of materials, a first material with corrosion performance suitable for the operating environment of the evaporator is selected by using a simulation liquid in a quick screening test, and vanadium ions are used in the simulation liquid to simulate plutonium ions in the radioactive liquid;

[0043] 2) A second material is selected by performing a corrosion test on the first material using a simulation liquid;

[0044] 3) A simulation evaporator product is selected by performing a corrosion body test on the second material, wherein the corrosion body test refers to processing the second material into a simulation evaporator, and the simulation liquid is used in the simulation evaporator to simulate the operation of the radioactive liquid in the evaporator.

[0045] The corrosion test method for the simulation liquid of the evaporator for radioactive liquid in the present embodiment has the following beneficial effects:

[0046] (1) A simulation feed solution preparation and corrosion test method for the post-treatment plant plutonium-containing evaporator is developed, which reasonably and effectively determines the corrosion resistance of the plutonium-containing evaporator material, and plays a guiding role in the research and operation of the plutonium-containing evaporator.

[0047] (2) A simulation feed solution preparation method for the post-treatment plant plutonium-containing evaporator is determined, which has good simulation and strong operability.

[0048] (3) A corrosion test method for the plutonium-containing evaporator is provided, including the composition of the simulation feed solution, the test conditions, and the test content, and the test method is simple and reasonable, and has good economy.

[0049] Example 2

[0050] The embodiment provides a corrosion test method for a simulation feed solution of a plutonium-containing evaporator, which comprises the following steps:

[0051] 1) For at least two kinds of materials, a first material with corrosion resistance suitable for the operating environment of the evaporator is selected by using a simulation feed solution in a quick screening test, and vanadium ions are used in the simulation feed solution to simulate plutonium ions in the radioactive feed solution.

[0052] 2) A second material is selected by performing a corrosion test on the first material using a simulation feed solution.

[0053] 3) A simulation evaporator product is selected by performing a corrosion body test on the second material, wherein the second material is processed into a simulation evaporator, and the simulation feed solution is used in the simulation evaporator to simulate the operation of the radioactive feed solution in the evaporator.

[0054] The plutonium-containing evaporator in the post-treatment plant mainly includes two types, one is a plutonium concentration evaporator, and the other is a mother liquor evaporator. The plutonium concentration evaporator is used for concentrating the plutonium-containing radioactive feed solution, and the mother liquor evaporator is used for evaporating the radioactive mother liquor.

[0055] Among a plurality of materials, at least two are selected for quick screening, a material is preliminarily determined quickly using fewer tests, a corrosion test is performed on the material to obtain the corrosion performance, and it is determined that the material is usable. Then, a corrosion body test is performed to verify that the selected material is indeed usable. The corrosion body test simulates the actual equipment, and the test conditions are closer to the equipment operating environment and more accurate. The corrosion test can use small parts such as plates or pipes or welded joints, and the test conditions can be similar to or more severe than the equipment operating environment.

[0056] When the first material is one material, the second material is the same material as the first material. When the number of the first material is greater than one material, the first material includes the second material.

[0057] Preferably, when the evaporator is used for concentrating a plutonium-containing radioactive feed liquid, the plutonium-containing radioactive feed liquid does not include a radioactive mother liquor, the plutonium-containing radioactive feed liquid includes plutonium ions, fission elements, the plutonium-containing radioactive feed liquid is a nitric acid system, the concentration of the plutonium ions is 4.1 x 10 -3 ~ 1.67 mol / L.

[0058] The plutonium ions in the plutonium-containing feed liquid of the plutonium concentration evaporator are replaced by vanadium ions.

[0059] Preferably, the minimum value of the vanadium ion concentration in the simulation feed liquid is not less than the concentration of the plutonium in the plutonium-containing radioactive feed liquid in the initial state of the evaporator when the plutonium is concentrated, and the maximum value of the vanadium ion concentration is not more than three times the concentration of the plutonium in the plutonium-containing radioactive feed liquid after the concentration.

[0060] Preferably, the non-radioactive reagents (if any) in the simulation feed liquid remain consistent with the plutonium-containing radioactive feed liquid (real material) in the initial state, such as hydrazine, hydroxylamine nitrate, etc.

[0061] Preferably, the concentration of nitric acid needs to consider the maximum and minimum concentrations during the operation of the evaporator, the concentration of nitric acid in the simulation feed liquid is 0.5 ~ 16 mol / L, and the concentration of the fission element in the simulation feed liquid is less than 10 -3 ~ 10 -6 mol / L, which can be considered to have no effect on corrosion, and no additional simulation elements are added.

[0062] The plutonium-containing feed liquid of the mother liquor evaporator is replaced by vanadium ions.

[0063] Preferably, the radioactive feed liquid is a radioactive mother liquor, when the evaporator is used for evaporating the radioactive mother liquor, the radioactive mother liquor includes plutonium ions, metal ions (such as manganese ions or potassium permanganate), the radioactive mother liquor is an oxalic acid system or a nitric acid system, and the concentration of the plutonium ions is 4.1 x 10 -6 ~ 8.4 x 10 -2 mol / L.

[0064] Preferably, the radioactive feed liquid is a radioactive mother liquor,

[0065] The minimum value of the vanadium ion concentration in the simulation feed liquid is not less than the concentration of the plutonium in the radioactive mother liquor in the initial state of the evaporator, and the maximum value of the vanadium ion concentration is not more than three times the concentration of the plutonium in the plutonium-containing radioactive feed liquid after the concentration.

[0066] Preferably, the metal ions in the radioactive mother liquor remain consistent with the radioactive mother liquor (real material) in the initial state, such as manganese ions or potassium permanganate, etc.

[0067] The concentration of nitric acid needs to consider the maximum and minimum concentrations during the operation of the evaporator, the concentration of nitric acid in the simulation feed liquid is 0.5 ~ 16 mol / L,

[0068] The concentration of oxalic acid in the simulated feed solution is consistent with that of the radioactive mother liquor (real material), and the maximum concentration of oxalic acid during the operation of the evaporator needs to be considered,

[0069] The concentration of the fragment element in the simulated feed solution is less than 10 -3 ~ 10 -6 mol / L, which can be considered to have no effect on corrosion, and no additional simulation elements are added.

[0070] Preferably, the temperature at which the simulated feed solution in step 3) is operated in the simulated evaporator is 20-140°C, and the pressure is -15-2 kPa.

[0071] Preferably, in step 1), the fast screening test includes: a first electrochemical corrosion test, a first uniform corrosion test.

[0072] Specifically, the fast screening test selects samples of multiple materials, conducts a first electrochemical corrosion and a first uniform corrosion test, and quickly screens out one or more samples with corrosion performance suitable for the operating environment of the plutonium-containing evaporator.

[0073] Preferably, in step 1), the test conditions of the fast screening test are the highest temperature in the fast screening preset temperature range and the maximum pressure in the fast screening preset pressure range.

[0074] Specifically, the test conditions of the fast screening test should be as few as possible to achieve the purpose of rapid screening, i.e., selecting the most stringent conditions, the highest temperature and the maximum pressure, at least the boiling state.

[0075] Preferably, in step 1), the test conditions of the fast screening test are the most corrosive corrosion solution ratio in the preset corrosion range, and the maximum concentration of each component in the preset concentration range of the simulated feed solution is superimposed.

[0076] Specifically, the most corrosive ratio is selected when the simulated feed solution of the fast screening test is prepared to achieve the purpose of rapid screening, and the maximum concentrations of vanadium ions, nitric acid, non-radioactive reagents (if any), manganese ions or potassium permanganate (if any), and oxalic acid (if any) are superimposed.

[0077] Preferably, in step 2), the corrosion test includes: a second electrochemical corrosion test, a second uniform corrosion test, and a localized corrosion test.

[0078] Specifically, the corrosion test refers to the second electrochemical corrosion test, the second uniform corrosion test, and the localized corrosion test conducted on one or more samples determined in the fast screening stage.

[0079] Preferably, in the step 2), the test conditions of the corrosion test are the highest temperature in the preset temperature range, the lowest temperature, the maximum pressure in the preset pressure range, and the minimum pressure.

[0080] Specifically, the test conditions of the corrosion test should consider the pressure and temperature changes during the operation of the evaporator, and at least include the highest temperature and the maximum pressure, and also include the lowest temperature and the minimum pressure as comparative research conditions.

[0081] Preferably, the concentration of the simulated feed liquid includes any one or several of the maximum vanadium ion concentration, nitric acid concentration, non-bleeding reagent concentration, manganese ion, potassium permanganate concentration, and oxalic acid concentration in the preset concentration range.

[0082] and any one or several of the minimum vanadium ion concentration, nitric acid concentration, non-bleeding reagent concentration, manganese ion, potassium permanganate concentration, and oxalic acid concentration.

[0083] Specifically, the preparation of the simulated feed liquid for the corrosion test should include the concentration changes of the feed liquid during the operation of the evaporator, i.e., the maximum vanadium ion concentration, nitric acid concentration, non-bleeding reagent (if any) concentration, manganese ion or potassium permanganate (if any) concentration, and oxalic acid concentration (if any), and the minimum vanadium ion concentration, nitric acid concentration, non-bleeding reagent (if any) concentration, manganese ion or potassium permanganate (if any) concentration, and oxalic acid concentration (if any). If necessary, several groups of simulated feed liquid ratios can be combined within the maximum and minimum ranges according to the characteristics of each material on the material corrosion.

[0084] Preferably, the simulated evaporator in the step 3) includes a simulated evaporator tank body and a welded joint provided on the simulated evaporator tank body. Specifically, the simulated evaporator includes a plate material for the simulated evaporator tank body.

[0085] Specifically, the corrosion body test is for materials selected for the quick screening test and the corrosion test, which are expensive and have less working conditions, and the specific material corrosion performance is less known.

[0086] Preferably, the simulated evaporator in the step 3) has an outer size not greater than that of the evaporator, and the internal component structure and type of the simulated evaporator are consistent with those of the plutonium-containing evaporator, but the number of internal components is greatly reduced, and the number of internal components of the simulated evaporator with the same structure is only 1-2.

[0087] Specifically, the test object of the corrosion body test is an equipment with the same or slightly smaller outer size as the plutonium-containing evaporator.

[0088] Preferably, the test time of the corrosion body test in the step 3) is not less than 1 month.

[0089] Specifically, the test conditions of the corrosion body test are consistent with the actual plutonium-containing evaporator, and the test time is determined according to the rapid screening test and the corrosion test, and the test time is not less than 1 month, and the test time is as long as possible under the condition.

[0090] Specifically, the composition of the simulated solution in the corrosion body test matches the concentration of the initial material when the plutonium-containing evaporator is not concentrated.

[0091] Specifically, the rapid screening test mainly uses more severe conditions to quickly select one or several materials through a small amount of tests.

[0092] The role of the corrosion test is to obtain the corrosion performance of the material suitable for the evaporator through a large amount of tests, and to determine that the material can be used for the evaporator according to the plate, pipe and welded joint that can appear in the structure of the evaporator equipment. If only one material is selected by the rapid screening test, the corrosion test is only done on one material, and if two materials are selected by the rapid screening test, the corrosion test is done on two materials. Because the test amount is large, it is not appropriate to exceed two.

[0093] The corrosion test finally determines and selects one material for the corrosion body test.

[0094] Specifically, the corrosion test method for the simulated solution of the evaporator for radioactive solution provided in the embodiment includes the following steps:

[0095] The plutonium concentration evaporator assumes that the feed liquid before evaporation is 20 g / L of plutonium, 0.5 mol / L of hydrazine, the concentration of the fissile element is less than 10 - 5 mol / L, and the concentration of nitric acid is 0.7 mol / L. It is assumed that the feed liquid after evaporation is 100 g / L of plutonium, 0 mol / L of hydrazine, the concentration of the fissile element is less than 10 - 4 mol / L, and the concentration of nitric acid is 10 mol / L.

[0096] According to the present application, the composition of the simulated solution is: the minimum concentration of vanadium is 0.0837 mol / L, the maximum concentration is 1.046 mol / L, the concentration of nitric acid is 0.7-10 mol / L, the concentration of hydrazine is 0-0.5 mol / L, and the fissile element is not considered.

[0097] The stop temperature of the evaporator is 20℃, and the pressure is normal pressure; the running temperature is 120℃, and the pressure is normal pressure.

[0098] Corrosion test method:

[0099] ​Fast screening test, select several materials of plate and welded joints, with vanadium 1.046 mol / L, nitric acid 10 mol / L, hydrazine 0.5 mol / L to carry out electrochemical test, uniform corrosion test. Test conditions are boiling state, pressure normal pressure. Select one or several materials.

[0100] Corrosion test, the material determined by fast screening test, with vanadium 1.046 mol / L, nitric acid 10 mol / L, hydrazine 0.5 mol / L and vanadium 0.0837 mol / L, nitric acid 0.7 mol / L to carry out electrochemical test, uniform corrosion test, local corrosion test. Test conditions are boiling state, pressure normal pressure; 20℃, pressure normal pressure.

[0101] Corrosion body test, for the above determined material, process the equipment with the same size as the evaporator, and only one purchased part; with vanadium 0.0837 mol / L, nitric acid 0.7 mol / L, hydrazine 0.5 mol / L to carry out evaporation and concentration test, temperature 120℃, pressure normal pressure during operation. Test time is 2 months.

[0102] The material determined by the corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has a uniform corrosion rate of less than 0.05-0.1 mm / year, and no obvious pitting and other material changes occur, indicating that the corrosion resistance is good, and the evaporator can be used.

[0103] The method in the embodiment proposes a simulation liquid preparation method and a composition ratio of the simulation liquid which are good in simulation and strong in operability for a plutonium-containing evaporator, and gives a test method which can quickly detect the corrosion resistance of the equipment material of the plutonium-containing evaporator according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and strong in operability.

[0104] The corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has the following beneficial effects:

[0105] (1) A simulation liquid preparation and corrosion test method for a plutonium-containing evaporator in a reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0106] (2) A simulation liquid preparation method for a plutonium-containing evaporator in a reprocessing plant is determined, which is good in simulation and strong in operability;

[0107] (3) A corrosion test method for a plutonium-containing evaporator is provided, including the composition of the simulation liquid for the test, the test conditions, and the test content, and the test method is simple and reasonable, and good in economy.

[0108] Example 3

[0109] Specifically, the embodiment provides a corrosion test method of a simulated feed liquid of an evaporator for a radioactive feed liquid, which comprises the following steps, and is different from the embodiment 2 in that:

[0110] The mother liquor evaporator is assumed that the feed liquid before evaporation is 1 g / L of plutonium, 0.1 g / L of potassium permanganate, and the concentration of the fission fragment element is lower than 10 - 6 mol / L, the concentration of nitric acid is 2 mol / L, and the concentration of oxalic acid is 0.2 mol / L. The feed liquid after evaporation is assumed to be 5 g / L of plutonium, 0.3 g / L of manganese ions, and the concentration of the fission fragment element is lower than 10 -5 mol / L, the concentration of nitric acid is 8 mol / L, and the concentration of oxalic acid is 0.01 mol / L.

[0111] According to the embodiment, the simulated feed liquid is composed of: the minimum concentration of vanadium is 0.0041 mol / L, and the maximum concentration of vanadium is 0.041 mol / L, the concentration of nitric acid is 2-8 mol / L, the concentration of potassium permanganate is 0.1 g / L (the concentration of manganese ions is 0.3 g / L), the concentration of oxalic acid is 0.01-0.2 mol / L, and the fission fragment element is not considered.

[0112] The stop temperature of the evaporator is 20 ℃, and the pressure is normal pressure; the running temperature is 130 ℃, and the pressure is normal pressure.

[0113] The corrosion test method comprises the following steps:

[0114] The fast screening test selects several materials of plate and welded joints, and carries out electrochemical tests and uniform corrosion tests on the materials with vanadium 0.041 mol / L, nitric acid 8 mol / L, potassium permanganate 0.1 g / L, and oxalic acid 0.2 mol / L. The test conditions are boiling state and normal pressure.

[0115] The corrosion test, the materials of plate and welded joints determined by the fast screening test, carry out electrochemical tests, uniform corrosion tests, and local corrosion tests on the materials with vanadium 0.041 mol / L, nitric acid 8 mol / L, potassium permanganate 0.1 g / L, and oxalic acid 0.2 mol / L, and vanadium 0.0041 mol / L, nitric acid 2 mol / L, manganese ions 0.3 g / L, and oxalic acid 0.01 mol / L. The test conditions are boiling state and normal pressure; 20 ℃ and normal pressure.

[0116] The corrosion body test is aimed at the above-determined material, processes an equipment with the same size as the evaporator and two purchased parts inside; vanadium 0.0041 mol / L, nitric acid 2 mol / L, potassium permanganate 0.1 g / L, and oxalic acid 0.2 mol / L carry out evaporation and concentration tests, the running temperature is 130 ℃, and the pressure is normal pressure. The test time is 3 months.

[0117] The material determined by the corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment has a uniform corrosion rate of less than 0.05-0.1 mm / year, and no obvious pitting and other material changes occur, indicating that the corrosion resistance is good and the material can be used for the evaporator.

[0118] The method in the embodiment provides a simulated feed liquid preparation method and a composition ratio of the simulated feed liquid, which has good simulation and strong operability, and according to the working characteristics of the plutonium-containing evaporator, a test method for rapidly detecting the corrosion resistance of the equipment material of the plutonium-containing evaporator is provided. The method is reasonable, efficient and has strong operability.

[0119] The corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment has the following beneficial effects:

[0120] (1) A simulated feed liquid preparation and corrosion test method for a plutonium-containing evaporator in a reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0121] (2) A simulated feed liquid preparation method for a plutonium-containing evaporator in a reprocessing plant is determined, which has good simulation and strong operability;

[0122] (3) A corrosion test method for a plutonium-containing evaporator is provided, which includes the composition of the simulated feed liquid for the test, test conditions, and test content. The test method is simple, reasonable, and economical.

[0123] Embodiment 4

[0124] The corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment includes the following steps, and the difference from Embodiment 2 is:

[0125] The plutonium concentration of the feed liquid before evaporation is 1 g / L, the hydrazine concentration is 0.5 mol / L, the fissile element concentration is less than 10 - 6 mol / L, and the nitric acid concentration is 0.5 mol / L. The plutonium concentration of the feed liquid after evaporation is 5 g / L, the hydrazine concentration is 0 mol / L, the fissile element concentration is less than 10 - 5 mol / L, and the nitric acid concentration is 7.5 mol / L.

[0126] According to the present application, the composition of the simulated feed liquid is as follows: the minimum concentration of vanadium is 0.0041 mol / L, the maximum concentration of vanadium is 0.063 mol / L, the nitric acid concentration is 0.5-7.5 mol / L, the hydrazine concentration is 0-0.5 mol / L, and the fissile element is not considered.

[0127] The stop temperature of the evaporator is 20℃, and the pressure is normal pressure; the running temperature is 140℃, and the pressure is -15 kPa.

[0128] Corrosion test method:

[0129] Fast screening test, select several materials of plate and welded joints, to vanadium 0.063 mol / L, nitric acid 7.5 mol / L, hydrazine 0.5 mol / L to carry out electrochemical test, uniform corrosion test. Test conditions are boiling state, pressure-15kPa. Select one or several materials.

[0130] Corrosion test, the material determined by fast screening test, to vanadium 0.063 mol / L, nitric acid 7.5 mol / L, hydrazine 0.5 mol / L and vanadium 0.0041 mol / L, nitric acid 0.5 mol / L to carry out electrochemical test, uniform corrosion test, localized corrosion test. Test conditions are boiling state, pressure-15kPa; 20℃, pressure-15kPa.

[0131] Corrosion body test, for the above-mentioned one material, process the equipment with the same size as the evaporator, and only one purchased part; to vanadium 0.0041 mol / L, nitric acid 0.5 mol / L, hydrazine 0.5 mol / L to carry out evaporation and concentration test, temperature 140℃, pressure-15kPa during operation. Test time is 2 months.

[0132] The material determined by the corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has a uniform corrosion rate of less than 0.05-0.1 mm / year, and no obvious pitting and other material changes occur, indicating that the corrosion resistance is good, and the evaporator can be used.

[0133] The method in the embodiment proposes a simulation liquid preparation method and a composition ratio of the simulation liquid which are good in simulation and strong in operability, and gives a test method which can quickly detect the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and strong in operability.

[0134] The corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has the following beneficial effects:

[0135] (1) A simulation liquid preparation and corrosion test method for a plutonium-containing evaporator in a reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0136] (2) A simulation liquid preparation method for a plutonium-containing evaporator in a reprocessing plant is determined, which is good in simulation and strong in operability;

[0137] (3) The corrosion test method of the plutonium evaporation device is provided, including the simulated feed liquid composition, test conditions and test contents, and the test method is simple, reasonable and economical.

[0138] Embodiment 5

[0139] The corrosion test method of the simulated feed liquid of the evaporation device for the radioactive feed liquid is provided in the embodiment, and the difference from the embodiment 2 is that the steps include:

[0140] The plutonium concentration evaporation device is assumed that the feed liquid before evaporation is 80 g / L of plutonium, 0.5 mol / L of hydrazine, and the concentration of the fissile element is less than 10 - 4 mol / L, and the concentration of nitric acid is 2 mol / L. It is assumed that the feed liquid after evaporation is 400 g / L of plutonium, 0 mol / L of hydrazine, and the concentration of the fissile element is less than 10 - 3 mol / L, and the concentration of nitric acid is 16 mol / L.

[0141] According to the application, the simulated feed liquid composition is taken: the minimum concentration of vanadium is 0.33 mol / L, the maximum concentration is 1.67 mol / L, the concentration of nitric acid is 2-16 mol / L, the concentration of hydrazine is 0-0.5 mol / L, and the fissile element is not considered.

[0142] The evaporation device stops at 30℃, and the pressure is normal pressure; when running, the temperature is 130℃, and the pressure is 24 kPa.

[0143] The corrosion test method is:

[0144] The fast screening test selects several materials of the plate and the welded joint, and carries out the electrochemical test and the uniform corrosion test with 1.67 mol / L of vanadium, 16 mol / L of nitric acid and 0.5 mol / L of hydrazine. The test conditions are boiling state and 24 kPa of pressure. One or several materials are screened out.

[0145] The corrosion test, the material determined by the fast screening test, carries out the electrochemical test, the uniform corrosion test and the local corrosion test with 1.67 mol / L of vanadium, 16 mol / L of nitric acid and 0.5 mol / L of hydrazine, and 0.33 mol / L of vanadium and 2 mol / L of nitric acid. The test conditions are boiling state, 24 kPa of pressure, 30℃ and 24 kPa of pressure, respectively.

[0146] The corrosion body test is carried out on the above-mentioned determined material, and the equipment with the same size as the evaporation device and only one purchased part is processed; the evaporation concentration test is carried out with 0.33 mol / L of vanadium, 2 mol / L of nitric acid and 0.5 mol / L of hydrazine, and the running temperature is 130℃ and the pressure is 24 kPa. The test time is 2 months.

[0147] The material determined by the corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment has a uniform corrosion rate of less than 0.05-0.1 mm / year, and no obvious change of the material such as pitting corrosion occurs, indicating that the corrosion resistance is good, and the material can be used for the evaporator.

[0148] The method in the embodiment provides a simulated feed liquid preparation method and a composition ratio of the simulated feed liquid, which has good simulation and strong operability, and according to the working characteristics of the plutonium-containing evaporator, a test method for rapidly detecting the corrosion resistance of the equipment material of the plutonium-containing evaporator is provided. The method is reasonable, efficient and has strong operability.

[0149] The corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment has the following beneficial effects:

[0150] (1) A simulated feed liquid preparation and corrosion test method for a plutonium-containing evaporator in a reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0151] (2) A simulated feed liquid preparation method for a plutonium-containing evaporator in a reprocessing plant is determined, which has good simulation and strong operability;

[0152] (3) A corrosion test method for a plutonium-containing evaporator is provided, which includes the composition of the simulated feed liquid for the test, test conditions, and test content. The test method is simple, reasonable, and economical.

[0153] Embodiment 6

[0154] The corrosion test method of the simulated feed liquid of the evaporator for radioactive feed liquid in the embodiment includes the following steps, and the difference from the embodiment is:

[0155] The mother liquor evaporator is assumed to have plutonium 0.001 g / L, potassium permanganate 0.1 g / L, and the concentration of the fission fragment element is less than 10 -5 mol / L before evaporation, and the mother liquor evaporator is assumed to have plutonium 0.005 g / L, manganese ions 0.3 g / L, and the concentration of the fission fragment element is less than 10 -4 mol / L after evaporation.

[0156] According to the present application, the composition of the simulated feed liquid is as follows: the minimum concentration of vanadium is 4.1 x 10 -6 mol / L, and the maximum concentration is 6.3 x 10 -5 mol / L, the concentration of nitric acid is 0.5-16 mol / L, the concentration of potassium permanganate is 0.1 g / L (manganese ions 0.3 g / L), the concentration of oxalic acid is 0.01-0.2 mol / L, and the fission fragment element is not considered.

[0157] Evaporator stop temperature 20℃, pressure normal pressure; running temperature 140℃, pressure 24kPa.

[0158] Corrosion test method:

[0159] Fast screening test, select several materials of plate and welded joints, with vanadium 6.3×10 -5 mol / L, nitric acid 16mol / L, potassium permanganate 0.1g / L, oxalic acid concentration 0.2mol / L to carry out electrochemical test, uniform corrosion test. Test conditions are boiling state, pressure 24kPa. Select one or several materials.

[0160] Corrosion test, the material of plate and welded joints determined by fast screening test, with vanadium 6.3×10 -5 mol / L, nitric acid 16mol / L, potassium permanganate 0.1g / L, oxalic acid concentration 0.2mol / L and vanadium 4.1×10 -6 mol / L, nitric acid 0.5mol / L, manganese ion 0.3g / L, oxalic acid concentration 0.01mol / L to carry out electrochemical test, uniform corrosion test, localized corrosion test. Test conditions are boiling state, pressure 24kPa; 20℃, pressure 24kPa.

[0161] Corrosion body test, for the above determined one material, process the equipment with the same size as the evaporator, with 2 purchased parts inside; vanadium 4.1×10 -6 mol / L, nitric acid 0.5mol / L, potassium permanganate 0.1g / L, oxalic acid concentration 0.2mol / L to carry out evaporation concentration test, running temperature 140℃, pressure 24kPa. Test time is 3 months.

[0162] The material determined by the corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has uniform corrosion rate less than 0.05-0.1mm / year, and no obvious pitting and other material changes, which indicates that the corrosion resistance is good, and the material can be used for the evaporator.

[0163] The method in the embodiment proposes a simulation liquid preparation method and composition ratio of the simulation liquid with good simulation and strong operability for the plutonium-containing evaporator, and gives a test method for rapidly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and has strong operability.

[0164] The corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has the following beneficial effects:

[0165] (1) A simulation liquid preparation method for the evaporation of the post-processing plant containing plutonium is developed, which can reasonably and effectively determine the corrosion resistance of the material of the evaporation device containing plutonium, and plays a guiding role in the research and operation of the evaporation device containing plutonium.

[0166] (2) A simulation liquid preparation method for the evaporation of the post-processing plant containing plutonium is determined, which has good simulation and strong operability.

[0167] (3) A corrosion test method for the evaporation of the post-processing plant containing plutonium is provided, including the composition of the simulation liquid, the test conditions, and the test content. The test method is simple, reasonable, and economical.

[0168] Example 7

[0169] The corrosion test method for the simulation liquid of the evaporation device for radioactive liquid provided in this embodiment includes the following steps, and the difference from Example 3 is:

[0170] The mother liquor evaporator is assumed to have a plutonium concentration of 4 g / L, a potassium permanganate concentration of 0.1 g / L, a fissile element concentration of less than 10 - 4 mol / L, a nitric acid concentration of 2 mol / L, and an oxalic acid concentration of 0.2 mol / L before evaporation. After evaporation, the liquid is assumed to have a plutonium concentration of 20 g / L, a manganese ion concentration of 0.3 g / L, a fissile element concentration of less than 10 -3 mol / L, a nitric acid concentration of 8 mol / L, and an oxalic acid concentration of 0.01 mol / L.

[0171] According to the present application, the composition of the simulation liquid is as follows: the minimum concentration of vanadium is 0.0167 mol / L, the maximum concentration can be 0.083 mol / L, the concentration of nitric acid is 2-8 mol / L, the concentration of potassium permanganate is 0.1 g / L (manganese ion concentration is 0.3 g / L), the concentration of oxalic acid is 0.01-0.2 mol / L, and the fissile element is not considered.

[0172] The stop temperature of the evaporator is 30°C, and the pressure is normal pressure. When running, the temperature is 130°C, and the pressure is -15 kPa.

[0173] Corrosion test method:

[0174] Fast screening test: several materials of plate and welded joints are selected, and electrochemical test and uniform corrosion test are carried out with vanadium 0.083 mol g / L, nitric acid 8 mol / L, potassium permanganate 0.1 g / L, and oxalic acid concentration 0.2 mol / L. The test conditions are boiling state and pressure -15 kPa. One or several materials are selected.

[0175] The plate and the welded joint of the material determined by the corrosion test and the quick screening test are subjected to electrochemical test, uniform corrosion test and local corrosion test with vanadium 0.083 mol / L, nitric acid 8 mol / L, potassium permanganate 0.1 g / L and oxalic acid concentration 0.2 mol / L, and vanadium 0.0167 mol / L, nitric acid 2 mol / L, manganese ion 0.3 g / L and oxalic acid concentration 0.01 mol / L. The test conditions are boiling state and pressure-15 kPa, 30℃ and pressure-15 kPa, respectively.

[0176] The corrosion body test is performed on the above-determined material, and a device with the same size as the evaporator is processed, and two purchased parts are used. The evaporation and concentration test is performed with vanadium 0.0167 mol / L, nitric acid 2 mol / L, potassium permanganate 0.1 g / L and oxalic acid concentration 0.2 mol / L. The temperature during operation is 130℃, and the pressure is-15 kPa. The test time is 3 months.

[0177] The material determined by the corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has a uniform corrosion rate of less than 0.05-0.1 mm / year, and no obvious pitting and other material changes occur, indicating that the corrosion resistance is good, and the evaporator can be used.

[0178] The method in the embodiment proposes a simulation liquid preparation method and a composition ratio of the simulation liquid, which has good simulation and strong operability for the plutonium-containing evaporator. According to the working characteristics of the plutonium-containing evaporator, a test method for rapidly detecting the corrosion resistance of the equipment material is given. The method is reasonable, efficient and has strong operability.

[0179] The corrosion test method of the simulation liquid of the evaporator for radioactive liquid in the embodiment has the following beneficial effects:

[0180] (1) A simulation liquid preparation and corrosion test method for the plutonium-containing evaporator in the reprocessing plant is developed, which reasonably and effectively determines the corrosion resistance of the material of the plutonium-containing evaporator, and plays a guiding role in the research and operation of the plutonium-containing evaporator;

[0181] (2) A simulation liquid preparation method for the plutonium-containing evaporator in the reprocessing plant is determined, which has good simulation and strong operability;

[0182] (3) A corrosion test method for the plutonium-containing evaporator is provided, which includes the composition of the simulation liquid for the test, the test conditions and the test content. The test method is simple, reasonable and economical.

[0183] It is understood that the above embodiments are only exemplary for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the present application, and these modifications and improvements are also considered as the protection scope of the present application.

Claims

1. A method for testing the corrosion of simulated feed liquid in an evaporator for radioactive feed liquid, characterized in that, Includes the following steps: 1) For samples of at least two materials, the first material whose corrosion performance is suitable for the evaporator operating environment is selected by using a simulated feed solution in a rapid screening test, in which vanadium ions are used to simulate plutonium ions in a radioactive feed solution; 2) Conduct a corrosion test on the first material using a simulated liquid solution to select the second material; 3) Conduct a corrosion body test on the second material. The corrosion body test refers to processing the second material into a simulated evaporator, using a simulated liquid to run in the simulated evaporator to simulate the operation of radioactive liquid in the evaporator, and selecting the simulated evaporator product.

2. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, When the evaporator is used to concentrate plutonium-containing radioactive feed solutions, the plutonium-containing radioactive feed solution does not include the radioactive mother liquor. The plutonium-containing radioactive feed solution includes plutonium ions and fragmented elements. The plutonium-containing radioactive feed solution is a nitric acid system, and the concentration of plutonium ions is 4.1 × 10⁻⁶. -3 ~1.67mol / L.

3. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1 or 2, characterized in that, The minimum vanadium ion concentration in the simulated feed solution is not less than the plutonium concentration in the radioactive feed solution containing plutonium in the initial state of the evaporator during plutonium concentration, and the maximum vanadium ion concentration is not more than three times the plutonium concentration in the radioactive feed solution containing plutonium after concentration.

4. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 3, characterized in that, The non-radioactive reagents in the simulated feed solution are kept consistent with the plutonium-containing radioactive feed solution in its initial state. The concentration of nitric acid in the simulated feed solution was 0.5–16 mol / L, and the concentration of cleavage elements in the simulated feed solution was less than 10. -3 ~10 - 6 mol / L.

5. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, The radioactive feed solution is a radioactive mother liquor. When the evaporator is used for evaporating the radioactive mother liquor, the radioactive mother liquor includes plutonium ions and metal ions. The radioactive mother liquor is an oxalic acid system or a nitric acid system, and the concentration of plutonium ions is 4.1 × 10⁻⁶. -6 ~8.4×10 -2 mol / L.

6. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1 or 5, characterized in that, The radioactive feed solution is a radioactive mother liquor. The minimum concentration of vanadium ions in the simulated feed solution is not less than the concentration of plutonium in the radioactive mother liquor in the initial state of the evaporator, and the maximum concentration of vanadium ions is not more than three times the concentration of plutonium in the concentrated plutonium-containing radioactive feed solution.

7. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 6, characterized in that, The metal ion content in the radioactive mother liquor remains consistent with that of the radioactive mother liquor in its initial state. The concentration of nitric acid in the simulated feed solution was 0.5–16 mol / L. The oxalic acid concentration in the simulated feed solution was consistent with that of the radioactive mother liquor. The concentration of fragmenting elements in the simulated feed solution is less than 10. -3 ~10 -6 mol / L.

8. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 3), the simulated liquid operates at a temperature of 20–140°C and a pressure of -15–2 kPa in the simulated evaporator.

9. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 1), the rapid screening test includes: a first electrochemical corrosion test and a first uniform corrosion test.

10. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 1), the test conditions for the rapid screening test are the highest temperature within the preset temperature range of the rapid screening test and the maximum pressure within the preset pressure range of the rapid screening test.

11. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 1), the test conditions for the rapid screening test are the ratio of the most corrosive solution within the preset corrosion range, plus the maximum concentration of each component within the preset concentration range of the simulated liquid.

12. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 2), the corrosion test includes: a second electrochemical corrosion test, a second uniform corrosion test, and a localized corrosion test.

13. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, In step 2), the test conditions for the corrosion test are the highest and lowest temperatures within the preset corrosion temperature range, and the maximum and minimum pressures within the preset corrosion pressure range.

14. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, The simulated evaporator in step 3) includes a simulated evaporator tank and a welded joint disposed on the simulated evaporator tank.

15. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, The external dimensions of the simulated evaporator in step 3) are no larger than those of the evaporator. The internal structure and type of the simulated evaporator are the same as those of the plutonium-containing evaporator. The number of internal components of the simulated evaporator is 1 to 2.

16. The corrosion test method for simulated feed liquid in an evaporator for radioactive feed liquid according to claim 1, characterized in that, The corrosion test in step 3) shall last for no less than one month.