Corrosion test method for simulating feed liquid of evaporator for radioactive feed liquid

Abstract

The invention discloses a corrosion test method of simulated feed liquid for an evaporator of radioactive feed liquid, which comprises the following steps of: 1) for samples of at least two materials, simulating plutonium ions in the radioactive feed liquid by using the simulated feed liquid in a fast screening test and using vanadium ions in the simulated feed liquid to simulate plutonium ions in the radioactive feed liquid; selecting a first material of which the corrosion performance is suitable for an evaporator operation environment; 2) carrying out a corrosion test on the first material, using the simulated material liquid in the corrosion test, and selecting a second material; and (3) a corrosion body test is conducted on the second material, specifically, the second material is processed into a simulation evaporator, in the corrosion body test, the simulation feed liquid is used for running in the simulation evaporator to simulate running of the radioactive feed liquid in the evaporator, and a simulation evaporator product is selected. According to the method, the corrosion resistance of the plutonium-containing evaporator material is reasonably and effectively determined, the method plays a guiding role in research and operation of the plutonium-containing evaporator, and the method is good in simulation performance and high in operability.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear fuel post-processing, and in particular relates to a corrosion test method for a simulated liquid used in an evaporator of radioactive liquid. Background Art

[0002] Nuclear fuel reprocessing plants mainly use the PUREX process. In the plutonium purification process, the reflux extraction method is mainly used to concentrate plutonium. In the plutonium tail process, the plutonium oxalate precipitation-filtration-calcination method is used to convert the plutonium nitrate solution into plutonium dioxide powder. During precipitation-filtration, the filtered mother liquor contains a small amount of plutonium that needs to be recovered, and the oxalic acid in it needs to be destroyed during recycling.

[0003] Introducing an evaporator containing plutonium feed liquid in the plutonium purification process will greatly improve the plutonium concentration efficiency, reduce the amount of waste liquid generated, and the time and cost of plant operation. Similarly, since the filtered mother liquor contains very little plutonium, using an evaporator to evaporate and concentrate the mother liquor and then return it to the system can greatly reduce the system's processing load and reduce the amount of additional reagents and radioactive waste liquid caused by concentrating the feed liquid in the previous process, meeting the principle of minimizing waste in the reprocessing plant, and at the same time improving the plant's operating throughput, which is highly economical.

[0004] At present, the technology of plutonium-containing evaporators has not been mastered. One of the main reasons is that its operating environment is special, involving high temperature, alternating hot and cold conditions, which are highly corrosive to the equipment materials. In addition, the plutonium liquid itself is corrosive, and additional oxalic acid, nitric acid, etc. will also cause corrosion to the equipment. Therefore, it is necessary to study the corrosion resistance of the plutonium-containing evaporator material.

[0005] At the same time, due to the strict management of plutonium and its extreme toxicity and radioactivity, it is impossible to use real plutonium liquid to carry out research and testing of plutonium-containing evaporators. Summary of the invention

[0006] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art and to provide a corrosion test method for a simulated liquid used in an evaporator for radioactive liquid, to use a simulated liquid with good simulation performance and strong operability to carry out research on plutonium-containing evaporators, to support research on evaporators for radioactive liquids containing plutonium and to provide technical support for their design and operation.

[0007] The invention provides a typical plutonium-containing radioactive liquid concentration evaporator and a simulated liquid evaporator, basic composition and corrosion test method thereof.

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

[0009] 1) For samples of at least two materials, a first material having corrosion performance suitable for an evaporator operating environment is selected by using a simulated liquid in a rapid screening test, wherein vanadium ions are used in the simulated liquid to simulate plutonium ions in the radioactive liquid;

[0010] 2) performing a corrosion test on the first material, using a simulated liquid in the corrosion test, and selecting the second material;

[0011] 3) Conducting a corrosion test on the second material. The corrosion test refers to processing the second material into a simulated evaporator. In the corrosion test, simulated liquid is run in the simulated evaporator to simulate the operation of the radioactive liquid in the evaporator, and a simulated evaporator product is selected.

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

[0013] Preferably, the minimum vanadium ion concentration in the simulated liquid is not less than the plutonium concentration in the plutonium-containing radioactive liquid 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 plutonium-containing radioactive liquid after concentration.

[0014] Preferably, the non-radioactive agent in the simulated liquid is kept consistent with the radioactive liquid containing plutonium in the initial state;

[0015] Preferably, the concentration of nitric acid in the simulated liquid is 0.5 to 16 mol / L, and the concentration of the fragmentation element in the simulated liquid is less than 10 -3 ~10 -6 mol / L.

[0016] Preferably, the radioactive liquid is a radioactive mother liquid. When the evaporator is used to evaporate the radioactive mother liquid, the radioactive mother liquid includes plutonium ions and metal ions. The radioactive mother liquid is an oxalic acid system or a nitric acid system. The concentration of plutonium ions is 4.1×10 -6 ~8.4×10 -2 mol / L.

[0017] Preferably, the radioactive liquid is a radioactive mother liquid.

[0018] The minimum value of the vanadium ion concentration in the simulated feed liquid is not less than the plutonium concentration 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 plutonium concentration in the radioactive feed liquid containing plutonium after concentration.

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

[0020] The nitric acid concentration in the simulated liquid is 0.5-16 mol / L.

[0021] The concentration of oxalic acid in the simulated liquid is consistent with that of the radioactive mother liquid.

[0022] The concentration of the fragmentation element in the simulated liquid is less than 10 -3 ~10- 6 mol / L.

[0023] Preferably, in step 3), the temperature of the simulated liquid in the simulated evaporator is 20 to 140° C., and the pressure is -15 to 2 kPa.

[0024] Preferably, in step 1), the rapid screening test includes: a first electrochemical corrosion test and a first uniform corrosion test.

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

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

[0027] Preferably, in step 2), the corrosion test includes: a second electrochemical corrosion test, a second uniform corrosion test, and a local corrosion test.

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

[0029] Preferably, the concentration of the simulated liquid includes any one or more of the maximum vanadium ion concentration, nitric acid concentration, non-radioactive agent concentration, manganese ion concentration, potassium permanganate concentration, and oxalic acid concentration within a preset concentration range;

[0030] And any one or more of the corresponding minimum vanadium ion concentration, nitric acid concentration, non-radioactive agent 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 welding joint arranged on the simulated evaporator tank body.

[0032] Preferably, the outer dimensions of the simulated evaporator in step 3) are not larger than the evaporator, the structure and type of the internal components of the simulated evaporator are consistent with those of the plutonium-containing evaporator, and the number of the internal components of the simulated evaporator is 1 to 2.

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

[0034] The method of the present invention proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

[0036] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

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

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

[0039] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific implementation methods.

[0040] Example 1

[0041] This embodiment provides a corrosion test method for a simulated liquid used in an evaporator of a radioactive liquid, comprising the following steps:

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

[0043] 2) performing a corrosion test on the first material, using a simulated liquid in the corrosion test, and selecting the second material;

[0044] 3) Conducting a corrosion test on the second material. The corrosion test refers to processing the second material into a simulated evaporator. In the corrosion test, simulated liquid is run in the simulated evaporator to simulate the operation of the radioactive liquid in the evaporator, and a simulated evaporator product is selected.

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

[0046] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

[0047] (2) A method for preparing simulated liquid for a plutonium-containing evaporator in a reprocessing plant was determined, which has good simulation and strong operability;

[0048] (3) A corrosion test method for a plutonium-containing evaporator is provided, including the simulated liquid composition, test conditions, and test content. The test method is simple, reasonable, and economical.

[0049] Example 2

[0050] This embodiment provides a corrosion test method for a simulated liquid used in an evaporator of a radioactive liquid, comprising the following steps:

[0051] 1) For samples of at least two materials, a first material having corrosion performance suitable for an evaporator operating environment is selected by using a simulated liquid in a rapid screening test, wherein vanadium ions are used in the simulated liquid to simulate plutonium ions in the radioactive liquid;

[0052] 2) performing a corrosion test on the first material, using a simulated liquid in the corrosion test, and selecting the second material;

[0053] 3) Conducting a corrosion test on the second material. The corrosion test refers to processing the second material into a simulated evaporator. In the corrosion test, simulated liquid is run in the simulated evaporator to simulate the operation of the radioactive liquid in the evaporator, and a simulated evaporator product is selected.

[0054] There are two main types of plutonium-containing evaporators in reprocessing plants: plutonium concentration evaporator and mother liquor evaporator. Plutonium concentration evaporator is used to concentrate radioactive liquid containing plutonium, while mother liquor evaporator is used to evaporate radioactive mother liquor.

[0055] Select at least two materials from a variety of materials for rapid screening, and use fewer tests to quickly preliminarily determine a material. Conduct corrosion tests on this material to obtain corrosion properties and determine whether it is usable. Then conduct corrosion body tests to verify that the selected material is indeed feasible. Corrosion body tests simulate actual equipment, and the test conditions are closer to the equipment operating environment and more accurate. Corrosion tests can use small components, such as plates or pipes or welded joints, and the test conditions can be similar to or more stringent 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 to concentrate the radioactive liquid containing plutonium, the radioactive liquid containing plutonium does not include a radioactive mother liquid, the radioactive liquid containing plutonium includes plutonium ions and fragment elements, the radioactive liquid containing plutonium is a nitric acid system, and the concentration of plutonium ions is 4.1×10 -3 ~1.67mol / 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 vanadium ion concentration in the simulated liquid is not less than the plutonium concentration in the plutonium-containing radioactive liquid 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 plutonium-containing radioactive liquid after concentration.

[0060] Preferably, the non-radioactive reagent (if any) in the simulated liquid is kept consistent with the radioactive liquid containing plutonium (real material) in the initial state, such as hydrazine, hydroxylamine nitrate, etc.

[0061] Preferably, the nitric acid concentration should take into account the maximum and minimum concentrations during the operation of the evaporator, the nitric acid concentration in the simulated liquid is 0.5-16 mol / L, and the concentration of the fragment elements in the simulated liquid is less than 10 -3 ~10 -6 mol / L, it can be considered that it has no effect on corrosion and no additional simulation elements are added.

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

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

[0064] Preferably, the radioactive liquid is a radioactive mother liquid.

[0065] The minimum value of the vanadium ion concentration in the simulated feed liquid is not less than the plutonium concentration 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 plutonium concentration in the radioactive feed liquid containing plutonium after concentration.

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

[0067] The nitric acid concentration needs to take into account the maximum and minimum concentrations during the operation of the evaporator. The nitric acid concentration in the simulated liquid is 0.5-16 mol / L.

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

[0069] The concentration of the fragmentation element in the simulated liquid is less than 10 -3 ~10 -6 mol / L, it can be considered that it has no effect on corrosion and no additional simulation elements are added.

[0070] Preferably, in step 3), the temperature of the simulated liquid in the simulated evaporator is 20 to 140° C., and the pressure is -15 to 2 kPa.

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

[0072] Specifically, the rapid screening test selects samples of various materials, conducts the first electrochemical corrosion test and the first uniform corrosion test, and quickly screens out one or several samples whose corrosion properties are suitable for the operating environment of the plutonium-containing evaporator.

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

[0074] Specifically, the test conditions for rapid screening tests should be as few as possible to achieve the purpose of rapid screening, that is, the most demanding conditions should be selected, with the highest temperature and pressure, at least boiling state.

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

[0076] Specifically, when preparing the simulated liquid for the rapid screening test, the most corrosive ratio is selected to achieve the purpose of rapid screening, and the maximum vanadium ion concentration, nitric acid concentration, non-radioactive reagent (if any) concentration, manganese ion or potassium permanganate (if any) concentration, and oxalic acid concentration (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 local corrosion test.

[0078] Specifically, the corrosion test indicator performs a second electrochemical corrosion test, a second uniform corrosion test, and a local corrosion test on one or several samples determined in the rapid screening stage.

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

[0080] Specifically, the test conditions of the corrosion test should take into account the pressure and temperature changes during the operation of the evaporator. The test conditions should at least include the highest temperature and maximum pressure. For comparative research, the test conditions of the lowest temperature and minimum pressure should also be included.

[0081] Preferably, the concentration of the simulated liquid includes any one or more of the maximum vanadium ion concentration, nitric acid concentration, non-radioactive agent concentration, manganese ion concentration, potassium permanganate concentration, and oxalic acid concentration within a preset concentration range;

[0082] And any one or more of the corresponding minimum vanadium ion concentration, nitric acid concentration, non-radioactive agent concentration, manganese ion concentration, potassium permanganate concentration, and oxalic acid concentration.

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

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

[0085] Specifically, the corrosion body test is aimed at situations where the materials selected for the rapid screening test and the corrosion test are expensive, have fewer operating conditions, and have little knowledge of their specific material corrosion properties.

[0086] Preferably, the outer dimensions of the simulated evaporator in step 3) are not larger than the evaporator, and the structure and type of the internal components 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 to 2.

[0087] Specifically, the test object of the corrosion body test is a device with the same or slightly smaller external dimensions as the plutonium-containing evaporator.

[0088] Preferably, the test time of the corrosion body test in 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 based on the rapid screening test and the corrosion test. The test time is not less than 1 month, and the test time can be extended as much as possible under certain conditions.

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

[0091] Specifically, rapid screening tests mainly use more stringent conditions to quickly select one or several materials through a small number of tests.

[0092] The purpose of the corrosion test is to obtain the corrosion performance of the material suitable for the evaporator through a large number of tests. It can be used for plates, pipes, welded joints, etc. that may appear in the evaporator equipment structure to determine whether the material can be used for the evaporator. If only one material is selected in the quick screening test, the corrosion test is only performed on one material. If two materials are selected in the quick screening test, the corrosion test is performed on both materials. Because the test volume is large, it is not advisable to exceed two materials.

[0093] The ultimate goal of corrosion testing is to determine\select a material for corrosion testing.

[0094] Specifically, this embodiment provides a corrosion test method for a simulated liquid for an evaporator of a radioactive liquid, comprising the following steps:

[0095] Plutonium concentration evaporator, assuming that the liquid before evaporation is plutonium 20g / L, hydrazine 0.5mol / L, and the concentration of fragment elements is less than 10 - 5 mol / L, nitric acid concentration 0.7mol / L. Assume that the liquid after evaporation is plutonium 100g / L, hydrazine 0mol / L, and the concentration of the fragment elements is less than 10 - 4 mol / L, nitric acid concentration 10mol / L.

[0096] According to the present invention, the simulated liquid composition is as follows: the lowest vanadium concentration is 0.0837 mol / L, the highest concentration is 1.046 mol / L, the nitric acid concentration is 0.7-10 mol / L, the hydrazine concentration is 0-0.5 mol / L, and the fragment elements are not considered.

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

[0098] Corrosion test method:

[0099] Rapid screening test, select plates and welded joints of several materials, and conduct electrochemical test and uniform corrosion test with 1.046mol / L vanadium, 10mol / L nitric acid and 0.5mol / L hydrazine. The test conditions are boiling state and normal pressure. One or several materials are screened out.

[0100] Corrosion test, plate and welded joint of materials determined by quick screening test, electrochemical test, uniform corrosion test and local corrosion test were carried out with 1.046mol / L vanadium, 10mol / L nitric acid, 0.5mol / L hydrazine and 0.0837mol / L vanadium, 0.7mol / L nitric acid. The test conditions were boiling state, normal pressure; 20℃, normal pressure.

[0101] Corrosion body test, for one of the materials identified above, the processing is consistent with the evaporator's external dimensions, and the equipment with only one purchased part is carried out; evaporation concentration test is carried out with 0.0837mol / L vanadium, 0.7mol / L nitric acid and 0.5mol / L hydrazine, the operating temperature is 120℃, and the pressure is normal pressure. The test time is 2 months.

[0102] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0103] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

[0105] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

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

[0107] (3) A corrosion test method for a plutonium-containing evaporator is provided, including the simulated liquid composition, test conditions, and test content. The test method is simple, reasonable, and economical.

[0108] Example 3

[0109] Specifically, this embodiment provides a corrosion test method for a simulated liquid for an evaporator of radioactive liquid, comprising the following steps, which differs from Embodiment 2 in that:

[0110] Mother liquor evaporator, assuming that the liquid before evaporation is plutonium 1g / L, potassium permanganate 0.1g / L, and the concentration of fragment elements is less than 10 - 6 mol / L, nitric acid concentration 2mol / L, oxalic acid 0.2mol / L. Assuming that the liquid after evaporation is plutonium 5g / L, manganese ion 0.3g / L, and the concentration of fragment elements is less than 10 -5 mol / L, nitric acid concentration 8mol / L, oxalic acid 0.01mol / L.

[0111] According to the present invention, the simulated liquid composition is as follows: the minimum vanadium concentration is 0.0041 mol / L, the maximum concentration can be 0.041 mol / L, the nitric acid concentration is 2-8 mol / L, potassium permanganate is 0.1 g / L (manganese ion is 0.3 g / L), oxalic acid is 0.01-0.2 mol / L, and the fragment elements are not considered.

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

[0113] Corrosion test method:

[0114] Rapid screening test, select several materials of plates and welded joints, and conduct electrochemical test and uniform corrosion test with 0.041mol / L vanadium, 8mol / L nitric acid, 0.1g / L potassium permanganate, and 0.2mol / L oxalic acid concentration. The test conditions are boiling state and normal pressure. One or several materials are screened out.

[0115] Corrosion test, plates and welded joints of materials determined by quick screening test, electrochemical test, uniform corrosion test and local corrosion test were carried out with 0.041mol / L vanadium, 8mol / L nitric acid, 0.1g / L potassium permanganate, 0.2mol / L oxalic acid concentration and 0.0041mol / L vanadium, 2mol / L nitric acid, 0.3g / L manganese ion, 0.01mol / L oxalic acid concentration. The test conditions were boiling state, normal pressure; 20℃, normal pressure.

[0116] Corrosion body test, for one of the materials determined above, the equipment with the same dimensions as the evaporator and two purchased parts; 0.0041mol / L vanadium, 2mol / L nitric acid, 0.1g / L potassium permanganate, 0.2mol / L oxalic acid concentration, evaporation concentration test, operating temperature 130℃, pressure normal pressure. The test time is 3 months.

[0117] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0118] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

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

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

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

[0123] Example 4

[0124] This embodiment provides a corrosion test method for a simulated liquid used in an evaporator of radioactive liquid, comprising the following steps, which differs from Embodiment 2 in that:

[0125] Plutonium concentration evaporator, assuming that the liquid before evaporation is plutonium 1g / L, hydrazine 0.5mol / L, and the concentration of fragment elements is less than 10 - 6 mol / L, nitric acid concentration 0.5mol / L. Assume that the liquid after evaporation contains 5g / L plutonium, 0mol / L hydrazine, and the concentration of the fragment elements is less than 10 - 5 mol / L, nitric acid concentration 7.5mol / L.

[0126] According to the present invention, the simulated liquid composition is as follows: the lowest vanadium concentration is 0.0041 mol / L, the highest concentration 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 fragment elements are not considered.

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

[0128] Corrosion test method:

[0129] Rapid screening test, select plates and welded joints of several materials, and conduct electrochemical tests and uniform corrosion tests with 0.063mol / L vanadium, 7.5mol / L nitric acid, and 0.5mol / L hydrazine. The test conditions are boiling state and pressure -15kPa. One or several materials are screened out.

[0130] Corrosion test, plate and weld joint of materials determined by quick screening test, electrochemical test, uniform corrosion test and local corrosion test were carried out with 0.063mol / L vanadium, 7.5mol / L nitric acid, 0.5mol / L hydrazine and 0.0041mol / L vanadium, 0.5mol / L nitric acid. The test conditions were boiling state, pressure -15kPa; 20℃, pressure -15kPa.

[0131] Corrosion test, for one of the materials identified above, the equipment is processed to be consistent with the evaporator's external dimensions, and only one purchased part is used; evaporation concentration test is carried out with 0.0041mol / L vanadium, 0.5mol / L nitric acid, and 0.5mol / L hydrazine, the operating temperature is 140℃, and the pressure is -15kPa. The test time is 2 months.

[0132] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0133] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

[0135] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

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

[0137] (3) A corrosion test method for a plutonium-containing evaporator is provided, including the simulated liquid composition, test conditions, and test content. The test method is simple, reasonable, and economical.

[0138] Example 5

[0139] This embodiment provides a corrosion test method for a simulated liquid used in an evaporator of radioactive liquid, comprising the following steps, which differs from Embodiment 2 in that:

[0140] Plutonium concentration evaporator, assuming that the liquid before evaporation is plutonium 80g / L, hydrazine 0.5mol / L, and the concentration of fragment elements is less than 10 - 4 mol / L, nitric acid concentration 2mol / L. Assume that the liquid after evaporation is plutonium 400g / L, hydrazine 0mol / L, and the concentration of the fragment elements is less than 10 - 3 mol / L, nitric acid concentration is 16mol / L.

[0141] According to the present invention, the simulated liquid composition is as follows: the lowest vanadium concentration is 0.33 mol / L, the highest concentration is 1.67 mol / L, the nitric acid concentration is 2-16 mol / L, the hydrazine concentration is 0-0.5 mol / L, and the fragment elements are not considered.

[0142] The evaporator stop temperature is 30℃ and the pressure is atmospheric pressure; the operating temperature is 130℃ and the pressure is 24kPa.

[0143] Corrosion test method:

[0144] Rapid screening test, select plates and welded joints of several materials, and conduct electrochemical test and uniform corrosion test with 1.67mol / L vanadium, 16mol / L nitric acid and 0.5mol / L hydrazine. The test conditions are boiling state and pressure 24kPa. One or several materials are screened out.

[0145] Corrosion test, plate and weld joint of materials determined by quick screening test, electrochemical test, uniform corrosion test and local corrosion test were carried out with 1.67mol / L vanadium, 16mol / L nitric acid, 0.5mol / L hydrazine and 0.33mol / L vanadium, 2mol / L nitric acid. The test conditions were boiling state, pressure 24kPa; 30℃, pressure 24kPa.

[0146] Corrosion body test, for one of the materials identified above, the processing is consistent with the evaporator's external dimensions, and the equipment with only one purchased part is carried out; evaporation concentration test is carried out with 0.33mol / L vanadium, 2mol / L nitric acid and 0.5mol / L hydrazine, the operating temperature is 130℃ and the pressure is 24kPa. The test time is 2 months.

[0147] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0148] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

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

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

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

[0153] Example 6

[0154] This embodiment provides a corrosion test method for a simulated liquid for an evaporator of radioactive liquid, comprising the following steps, which are different from the embodiment in that:

[0155] Mother liquor evaporator, assuming that the liquid before evaporation is plutonium 0.001g / L, potassium permanganate 0.1g / L, and the concentration of fragment elements is less than 10 -5 mol / L, nitric acid concentration 0.5mol / L, oxalic acid 0.2mol / L. Assuming that the liquid after evaporation is plutonium 0.005g / L, manganese ion 0.3g / L, and the concentration of fragment elements is less than 10 -4 mol / L, nitric acid concentration is 16mol / L, oxalic acid is 0.01mol / L.

[0156] According to the present invention, the simulated liquid composition is: the minimum vanadium concentration is 4.1×10 -6 mol / L, the highest concentration can be 6.3×10 -5 mol / L, nitric acid concentration 0.5~16mol / L, potassium permanganate 0.1g / L (manganese ion 0.3g / L), oxalic acid 0.01~0.2mol / L, fragment elements are not considered.

[0157] The evaporator stop temperature is 20℃ and the pressure is atmospheric pressure; the operating temperature is 140℃ and the pressure is 24kPa.

[0158] Corrosion test method:

[0159] Rapid screening test, selected several materials of plates 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 and uniform corrosion test. The test conditions are boiling state and pressure 24kPa. One or several materials are selected.

[0160] Corrosion test, rapid screening test to determine the material plate and welded joints, to 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 and local corrosion test. The test conditions are boiling state, pressure 24kPa; 20℃, pressure 24kPa.

[0161] Corrosion test, for one of the materials identified above, the processing is consistent with the evaporator's dimensions, and the equipment has 2 purchased parts; vanadium 4.1×10 -6 mol / L, 0.5mol / L nitric acid, 0.1g / L potassium permanganate, and 0.2mol / L oxalic acid were used to carry out evaporation concentration tests at a temperature of 140°C and a pressure of 24kPa. The test period was 3 months.

[0162] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0163] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

[0165] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

[0166] (2) A method for preparing simulated liquid for a plutonium-containing evaporator in a reprocessing plant was determined, which has good simulation and strong operability;

[0167] (3) A corrosion test method for a plutonium-containing evaporator is provided, including the simulated liquid composition, test conditions, and test content. The test method is simple, reasonable, and economical.

[0168] Example 7

[0169] This embodiment provides a corrosion test method for a simulated liquid used in an evaporator of radioactive liquid, comprising the following steps, which differs from Embodiment 3 in that:

[0170] Mother liquor evaporator, assuming that the liquid before evaporation is plutonium 4g / L, potassium permanganate 0.1g / L, and the concentration of fragment elements is less than 10 - 4 mol / L, nitric acid concentration 2mol / L, oxalic acid 0.2mol / L. Assuming that the liquid after evaporation is plutonium 20g / L, manganese ion 0.3g / L, and the concentration of fragment elements is less than 10 -3 mol / L, nitric acid concentration 8mol / L, oxalic acid 0.01mol / L.

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

[0172] The evaporator stop temperature is 30℃ and the pressure is normal pressure; the operating temperature is 130℃ and the pressure is -15kPa.

[0173] Corrosion test method:

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

[0175] Corrosion test, plates and welded joints of materials determined by quick screening test, electrochemical test, uniform corrosion test and local corrosion test were carried out with 0.083molg / L vanadium, 8mol / L nitric acid, 0.1g / L potassium permanganate, 0.2mol / L oxalic acid concentration and 0.0167mol / L vanadium, 2mol / L nitric acid, 0.3g / L manganese ion and 0.01mol / L oxalic acid concentration. The test conditions were boiling state, pressure -15kPa; 30℃, pressure -15kPa.

[0176] Corrosion body test, for one of the materials determined above, the equipment is processed with the same dimensions as the evaporator, and the number of purchased parts is 2; 0.0167mol / L vanadium, 2mol / L nitric acid, 0.1g / L potassium permanganate, 0.2mol / L oxalic acid concentration is used for evaporation concentration test, the operating temperature is 130℃, the pressure is -15kPa. The test time is 3 months.

[0177] The material determined by the corrosion test method of the simulated liquid for the evaporator of the radioactive liquid in this 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 can be used in the evaporator.

[0178] The method in this embodiment proposes a method for preparing a simulated liquid with good simulation and strong operability for a plutonium-containing evaporator and a composition ratio of the simulated liquid, and provides a test method for quickly detecting the corrosion resistance of the equipment material according to the working characteristics of the plutonium-containing evaporator. The method is reasonable, efficient and highly operable.

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

[0180] (1) A simulated liquid preparation and corrosion test method for the plutonium evaporator in a reprocessing plant was developed to reasonably and effectively determine the corrosion resistance of the material of the plutonium evaporator, which plays a guiding role in the research and operation of the plutonium evaporator;

[0181] (2) A method for preparing simulated liquid for a plutonium-containing evaporator in a reprocessing plant was determined, which has good simulation and strong operability;

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

[0183] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

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

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

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

4. The corrosion test method for a simulated liquid used in an evaporator of a radioactive liquid according to claim 3, characterized in that: The non-radioactive reagent in the simulated liquid is kept consistent with the radioactive liquid containing plutonium in the initial state; The concentration of nitric acid in the simulated liquid is 0.5-16 mol / L, and the concentration of the fragmentation element in the simulated liquid is less than 10 -3 ~10 - 6 mol / L.

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

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

7. The corrosion test method for a simulated liquid used in an evaporator of radioactive liquid according to claim 6, characterized in that: The metal ions in the radioactive mother solution remain the same as those in the initial state; The nitric acid concentration in the simulated liquid is 0.5-16 mol / L. The concentration of oxalic acid in the simulated liquid is consistent with that of the radioactive mother liquid. The concentration of the fragmentation element in the simulated liquid is less than 10 -3 ~10 -6 mol / L.

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

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

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

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

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

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

14. The corrosion test method for a simulated liquid used in an evaporator of radioactive liquid according to claim 1, characterized in that: The simulated evaporator in step 3) includes a simulated evaporator tank body and a welding joint arranged on the simulated evaporator tank body.

15. The corrosion test method for a simulated liquid used in an evaporator of radioactive liquid according to claim 1, characterized in that: The outer dimensions of the simulated evaporator in step 3) are not larger than the evaporator, the structure and type of the internal components of the simulated evaporator are consistent with those of the plutonium-containing evaporator, and the number of the internal components of the simulated evaporator is 1 to 2.

16. The corrosion test method for a simulated liquid used in an evaporator of radioactive liquid according to claim 1, characterized in that: The test time of the corrosion body test in step 3) is not less than 1 month.