A device and method for simulating boiling nitric acid galvanic corrosion testing of spent fuel reprocessing

Abstract

A kind of simulation spent fuel reprocessing boiling nitric acid galvanic corrosion testing device and method, device includes base, heating stage, reaction kettle, cover plate, object table, lifting adjusting mechanism and control panel;Heating stage is set in the top of base;Reaction kettle is set in the top of heating stage;Cover plate is set in the top of reaction kettle;Object table is located inside reaction kettle and is connected with cover plate by lifting adjusting mechanism;Control panel is set in base, temperature sensor is arranged in the inside of reaction kettle, heating stage and temperature sensor are electrically connected with control panel;Reaction kettle is connected with beaker storing saturated potassium nitrate solution by salt bridge tube, reference electrode is arranged in beaker, reference electrode is electrically connected with electrochemical workstation, galvanic couple sample is electrically connected with electrochemical workstation.The method is: temporarily support cover plate, install galvanic couple sample on object table, adjust the area ratio of galvanic couple sample and the distance between galvanic couple, cover plate is installed back to reaction kettle, add nitric acid to reaction kettle and adjust heating, adjust the height of galvanic couple sample.

Description

Technical Field

[0001] This invention belongs to the field of spent fuel reprocessing technology, and in particular relates to a test device and method for simulating spent fuel reprocessing boiling nitric acid galvanic corrosion. Background Technology

[0002] In the reprocessing of spent fuel, concentrated nitric acid, which has strong oxidizing properties, is used to dissolve the spent fuel. The dissolution of spent fuel is accompanied by high temperature and radioactivity, so the materials used in the boiling nitric acid environment have very high requirements for corrosion resistance.

[0003] Currently, the corrosion-resistant materials used in spent fuel reprocessing plants mainly include 304L stainless steel, 310L stainless steel, Ti-5Ta titanium alloy, Ti-5Ta-1.8Nb titanium alloy, zirconium alloy, etc. However, the connection or welding of these materials can cause significant potential differences, which in turn leads to galvanic corrosion, thus posing a huge safety hazard to spent fuel reprocessing.

[0004] At present, research on galvanic corrosion is usually limited to ambient and neutral environments, while research on galvanic corrosion in boiling nitric acid environments is relatively scarce. Therefore, it is essential to carry out research on galvanic corrosion in boiling nitric acid environments. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a simulated spent fuel reprocessing boiling nitric acid galvanic corrosion testing device and method, which can evaluate the galvanic corrosion performance of different metallic materials under the boiling nitric acid environment of spent fuel reprocessing, and can study the effects of temperature, galvanic distance, and area ratio on galvanic corrosion.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a simulated spent fuel reprocessing boiling nitric acid galvanic corrosion testing device, comprising a base, a heating platform, a reaction vessel, a cover plate, a loading platform, a lifting and adjusting mechanism, and a control panel; the heating platform is disposed above the base; the reaction vessel is disposed above the heating platform; the cover plate is disposed above the reaction vessel; the loading platform is located inside the reaction vessel and is connected to the cover plate via the lifting and adjusting mechanism; the control panel is disposed on the base, and the heating platform is electrically connected to the control panel; a temperature sensor is disposed inside the reaction vessel and is electrically connected to the control panel.

[0007] The lifting and adjusting mechanism includes a lead screw, a lead nut, a guide rod, a coupling, and a motor; the platform adopts a disc-shaped structure; the lead nut is fixedly installed at the center of the platform; the motor is vertically fixed above the cover plate with its shaft facing downwards; the lead screw is vertically arranged, with its upper end sealed through the cover plate and fixedly connected to the motor shaft via the coupling; the lead nut is fitted onto the lead screw; the guide rod is located on the side of the lead screw, parallel to the lead screw, and its top end is fixedly connected to the cover plate; a guide hole is provided on the platform, through which the guide rod passes; the motor is electrically connected to the control panel.

[0008] A first slide and a second slide are provided on the platform, and the first slide and the second slide are arranged parallel to each other. A first slider is installed in the first slide, and a first sample mounting groove is provided at the center of the bottom of the first slider. A first adapter hole is provided at the center of the interior of the first slider located above the first sample mounting groove. A first sample fastening screw is installed on the side of the first sample mounting groove. A second slider is installed in the second slide, and a second sample mounting groove is provided at the center of the bottom of the second slider. A second adapter hole is provided at the center of the interior of the second slider located above the second sample mounting groove. A second sample fastening screw is installed on the side of the second sample mounting groove.

[0009] The first sample mounting slot and the first adapter through hole form a two-stage stepped hole structure. The first thermocouple pair sample adopts a two-stage stepped cylindrical structure. The large-diameter section of the first thermocouple pair sample is sealed and inserted into the first sample mounting slot, and the small-diameter section of the first thermocouple pair sample is sealed and inserted into the first adapter through hole. A first protective sleeve covers the outside of the small-diameter section of the first thermocouple pair sample. The second sample mounting slot and the second adapter through hole form a two-stage stepped hole structure. The second thermocouple pair sample adopts a two-stage stepped cylindrical structure. The large-diameter section of the second thermocouple pair sample is sealed and inserted into the second sample mounting slot, and the small-diameter section of the second thermocouple pair sample is sealed and inserted into the second adapter through hole. A second protective sleeve covers the outside of the small-diameter section of the second thermocouple pair sample.

[0010] A salt bridge tube is sealed and inserted into the cover plate. The salt bridge tube has a liquid injection port in the middle of its body, and a sealing plug is installed at the injection port. A first porous plug is installed at the opening of the salt bridge tube inside the reactor. A beaker is located outside the reactor and is used to store a saturated potassium nitrate solution. A reference electrode is installed inside the beaker and is electrically connected to an electrochemical workstation via a first wire. A second porous plug is installed at the opening of the salt bridge tube outside the reactor, and the opening of the salt bridge tube with the second porous plug is located inside the beaker. The top of the small-diameter section of the first thermocouple is electrically connected to the electrochemical workstation via a second wire, and the perforations of the second wire with the first protective sleeve and the cover plate are sealed. The top of the small-diameter section of the second thermocouple is electrically connected to the electrochemical workstation via a third wire, and the perforations of the third wire with the second protective sleeve and the cover plate are sealed.

[0011] A tail gas condenser is sealed and inserted into the cover plate. One end of the tail gas condenser is connected to the inside of the reactor, and the other end is connected to the tail gas treatment equipment. A water-cooled heat exchange jacket is adjusted on the body of the tail gas condenser and is connected to the refrigeration circulating water station.

[0012] A simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test method, employing the aforementioned simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test device, includes the following steps:

[0013] Step 1: Prepare a temporary support and fix the cover plate horizontally on the temporary support. At this time, the cover plate is pre-installed with a lifting and adjusting mechanism, the lifting and adjusting mechanism is pre-installed with a platform, and the platform is pre-installed with a first slider and a second slider.

[0014] Step 2: Weld a second wire to the top of the small-diameter section of the first thermocouple sample, then pass the first protective sleeve through the second wire and cover the outside of the small-diameter section of the first thermocouple sample, and then seal the wire perforation of the first protective sleeve; at the same time, weld a third wire to the top of the small-diameter section of the second thermocouple sample, then pass the second protective sleeve through the third wire and cover the outside of the small-diameter section of the second thermocouple sample, and then seal the wire perforation of the second protective sleeve.

[0015] Step 3: Insert the processed first thermocouple sample into the first slider from below the stage, so that the smaller diameter section of the first thermocouple sample protrudes from above the first slider, and the larger diameter section of the first thermocouple sample is inserted into the first sample mounting slot; at the same time, insert the processed second thermocouple sample into the second slider from below the stage, so that the smaller diameter section of the second thermocouple sample protrudes from above the second slider, and the larger diameter section of the second thermocouple sample is inserted into the second sample mounting slot.

[0016] Step 4: Adjust the area of ​​the large diameter section of the first thermocouple sample exposed outside the first slider, and then tighten the first sample fixing screw; adjust the area of ​​the large diameter section of the second thermocouple sample exposed outside the second slider, and then tighten the second sample fixing screw until the ratio of the exposed area of ​​the large diameter section of the first thermocouple sample to that of the second thermocouple sample reaches the set value.

[0017] Step 5: Adjust the position of the first slider along the first slide rail, and at the same time adjust the position of the second slider along the second slide rail until the distance between the first and second thermocouple samples reaches the set value. Then, pass the second and third wires through the cover plate from below the cover plate, and then seal the wire holes in the cover plate.

[0018] Step 6: Transfer the cover plate from the temporary support to the reactor and fix the cover plate to the reactor. Then connect the second and third wires to the electrochemical workstation. Then pour saturated potassium nitrate solution into the beaker so that the reference electrode is immersed in the saturated potassium nitrate solution. At this time, the reference electrode has been connected to the electrochemical workstation in advance through the first wire.

[0019] Step 7: Insert one end of the prepared salt bridge tube into the reactor through the insertion hole on the cover plate, and insert the other end of the salt bridge tube into the beaker and immerse it in the saturated potassium nitrate solution. At this time, the inside of the salt bridge tube has been filled with electrolyte solution.

[0020] Step 8: Prepare a funnel and insert the handle of the funnel into the reactor through the insertion hole of the tail gas condenser pipe. Then, inject nitric acid into the reactor through the funnel until the amount of nitric acid injected reaches the set value. Then remove the funnel and insert the tail gas condenser pipe into the reactor through the insertion hole on the cover plate. At this time, the tail gas condenser pipe has been connected to the tail gas treatment equipment in advance, and a water-cooled heat exchange jacket has also been installed on the outside of the tail gas condenser pipe in advance.

[0021] Step 9: Start the heating platform through the control panel to heat the nitric acid inside the reactor until the temperature of the nitric acid reaches the set value. The temperature of the nitric acid is fed back to the control panel in real time through the temperature sensor. Then start the cooling circulating water station to cool the tail gas condenser through the water-cooled heat exchange jacket. Most of the tail gas condensate will drip back into the reactor along the tail gas condenser, and a small part of the tail gas will enter the tail gas treatment equipment for harmless treatment.

[0022] Step 10: After the nitric acid reaches the set temperature, start the motor through the control panel. The motor drives the lead screw to rotate synchronously. The rotational motion of the lead screw will be converted into the linear motion of the lead screw nut. In turn, the lead screw nut drives the stage to adjust its height. By adjusting the height of the stage, the first and second galvanic couple samples can be tested for galvanic corrosion in gas phase, liquid phase or gas-liquid two-phase alternating state.

[0023] Step 11: Repeat steps 1 to 10, except that the setting values ​​for the ratio of the exposed area of ​​the large diameter section of the first electrode pair sample to that of the second electrode pair sample are adjusted, the setting values ​​for the electrode pair spacing of the first electrode pair sample and the second electrode pair sample are adjusted, and the setting values ​​for the nitric acid heating temperature are adjusted.

[0024] The beneficial effects of this invention are:

[0025] The simulated spent fuel reprocessing boiling nitric acid galvanic corrosion test device and method of the present invention can evaluate the galvanic corrosion performance of different metal materials in the spent fuel reprocessing boiling nitric acid environment, and can study the effects of temperature, galvanic distance, and area ratio on galvanic corrosion. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of a simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion testing device according to the present invention;

[0027] Figure 2 for Figure 1 Sectional view of AA;

[0028] Figure 3 for Figure 1 Enlarged view of the middle section (I);

[0029] Figure 4 for Figure 1 Enlarged view of Part II;

[0030] In the diagram, 1—base, 2—heating platform, 3—reactor, 4—cover plate, 5—stage, 6—control panel, 7—temperature sensor, 8—lead screw, 9—lead nut, 10—guide rod, 11—coupling, 12—motor, 13—guide hole, 14—first slide rail, 15—second slide rail, 16—first slider, 17—first sample mounting slot, 18—first sample fixing screw, 19—second slider, 20—second sample mounting slot, 21—second sample fixing screw, 22—first... 23—Second thermocouple sample, 24—First protective sleeve, 25—Second protective sleeve, 26—Salt bridge tube, 27—Sealing plug, 28—First porous plug, 29—Beaker, 30—Saturated potassium nitrate solution, 31—Reference electrode, 32—First lead wire, 33—Electrochemical workstation, 34—Second porous plug, 35—Second lead wire, 36—Third lead wire, 37—Tail gas condenser, 38—Tail gas treatment equipment, 39—Water-cooled heat exchange jacket, 40—Refrigeration circulating water station, 41—Nitric acid. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] like Figures 1-4 As shown, a simulated spent fuel reprocessing boiling nitric acid galvanic corrosion test device includes a base 1, a heating platform 2, a reaction vessel 3, a cover plate 4, a platform 5, a lifting and adjusting mechanism, and a control panel 6. The heating platform 2 is positioned above the base 1; the reaction vessel 3 is positioned above the heating platform 2; the cover plate 4 is positioned above the reaction vessel 3; the platform 5 is located inside the reaction vessel 3 and is connected to the cover plate 4 via the lifting and adjusting mechanism; the control panel 6 is positioned on the base 1, and the heating platform 2 is electrically connected to the control panel 6; a temperature sensor 7 is installed inside the reaction vessel 3 and is electrically connected to the control panel 6.

[0033] The lifting and adjusting mechanism includes a lead screw 8, a lead screw nut 9, a guide rod 10, a coupling 11, and a motor 12; the platform 5 adopts a disc-shaped structure; the lead screw nut 9 is fixedly installed at the center of the platform 5; the motor 12 is vertically fixed above the cover plate 4 with the motor shaft facing downwards; the lead screw 8 is vertically arranged, and its upper end passes through the cover plate 4 and is fixedly connected to the motor shaft of the motor 12 through the coupling 11; the lead screw nut 9 is fitted onto the lead screw 8; the guide rod 10 is located on the side of the lead screw 8, is parallel to the lead screw 8, and its top end is fixedly connected to the cover plate 4; a guide hole 13 is provided on the platform 5, and the guide rod 10 passes through the guide hole 13; the motor 12 is electrically connected to the control panel 6.

[0034] A first slide rail 14 and a second slide rail 15 are provided on the stage 5, and the first slide rail 14 and the second slide rail 15 are arranged parallel to each other. A first slider 16 is installed in the first slide rail 14. A first sample mounting groove 17 is provided at the bottom center of the first slider 16. A first adapter hole is provided at the center of the inside of the first slider 16 above the first sample mounting groove 17. A first sample fastening screw 18 is installed on the side of the first sample mounting groove 17. A second slider 19 is installed in the second slide rail 15. A second sample mounting groove 20 is provided at the bottom center of the second slider 19. A second adapter hole is provided at the center of the inside of the second slider 19 above the second sample mounting groove 20. A second sample fastening screw 21 is installed on the side of the second sample mounting groove 20.

[0035] The first sample mounting groove 17 and the first adapter through hole form a two-stage stepped hole structure. The first thermocouple sample 22 adopts a two-stage stepped cylindrical structure. The large-diameter section of the first thermocouple sample 22 is sealed and inserted into the first sample mounting groove 17, and the small-diameter section of the first thermocouple sample 22 is sealed and inserted into the first adapter through hole. A first protective sleeve 24 covers the outside of the small-diameter section of the first thermocouple sample 22. The second sample mounting groove 20 and the second adapter through hole form a two-stage stepped hole structure. The second thermocouple sample 23 adopts a two-stage stepped cylindrical structure. The large-diameter section of the second thermocouple sample 23 is sealed and inserted into the second sample mounting groove 20, and the small-diameter section of the second thermocouple sample 23 is sealed and inserted into the second adapter through hole. A second protective sleeve 25 covers the outside of the small-diameter section of the second thermocouple sample 23.

[0036] A salt bridge tube 26 is sealed and inserted into the cover plate 4. The salt bridge tube 26 has a liquid injection port in the middle of its body, and a sealing plug 27 is installed at the liquid injection port. A first porous plug 28 is installed at the opening of the salt bridge tube 26 inside the reactor 3. A beaker 29 is provided outside the reactor 3 to store a saturated potassium nitrate solution 30. A reference electrode 31 is provided inside the beaker 29, and the reference electrode 31 is electrically connected to the electrochemical workstation 33 via a first wire 32. The salt bridge tube located outside the reactor 3... A second porous plug 34 is installed at the opening of the salt bridge tube 26, and the opening of the salt bridge tube 26 with the second porous plug 34 is located inside the beaker 29; the top of the small-diameter section of the first thermocouple is electrically connected to the electrochemical workstation 33 through the second wire 35, and the perforations of the second wire 35 and the first protective sleeve 24 and the cover plate 4 are sealed; the top of the small-diameter section of the second thermocouple is electrically connected to the electrochemical workstation 33 through the third wire 36, and the perforations of the third wire 36 and the second protective sleeve 25 and the cover plate 4 are sealed.

[0037] A tail gas condenser pipe 37 is sealed and inserted into the cover plate 4. One end of the tail gas condenser pipe 37 is connected to the inside of the reactor 3, and the other end of the tail gas condenser pipe 37 is connected to the tail gas treatment equipment 38. A water-cooled heat exchange jacket 39 is adjusted on the pipe body of the tail gas condenser pipe 37, and the water-cooled heat exchange jacket 39 is connected to the refrigeration circulating water station 40.

[0038] In this embodiment, the reactor 3, salt bridge tube 26, beaker 29, and tail gas condenser tube 37 are all made of glass; the cover plate 4, stage 5, lead screw 8, lead screw 9, guide rod 10, first slider 16, first sample fixing screw 18, second slider 19, second sample fixing screw 21, first protective sleeve 24, second protective sleeve 25, and sealing plug 27 are all made of polytetrafluoroethylene; the first porous plug 28 and the second porous plug 34 are both made of porous nano-ceramics.

[0039] A simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test method, employing the aforementioned simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test device, includes the following steps:

[0040] Step 1: Prepare a temporary support and fix the cover plate 4 horizontally on the temporary support. At this time, the cover plate 4 is pre-installed with a lifting adjustment mechanism, the lifting adjustment mechanism is pre-installed with a platform 5, and the platform 5 is pre-installed with a first slider 16 and a second slider 19.

[0041] Step 2: Weld a second wire 35 to the top of the small-diameter section of the first thermocouple sample 22 prepared in advance. Then, pass the first protective sleeve 24 through the second wire 35 and put it on the outside of the small-diameter section of the first thermocouple sample 22. After that, seal the wire through hole of the first protective sleeve 24. At the same time, weld a third wire 36 to the top of the small-diameter section of the second thermocouple sample 23 prepared in advance. Then, pass the second protective sleeve 25 through the third wire 36 and put it on the outside of the small-diameter section of the second thermocouple sample 23. After that, seal the wire through hole of the second protective sleeve 25.

[0042] Step 3: Insert the processed first thermocouple sample 22 from below the stage 5 into the first slider 16, so that the smaller diameter section of the first thermocouple sample 22 protrudes from above the first slider 16, and the larger diameter section of the first thermocouple sample 22 is inserted into the first sample mounting slot 17; at the same time, insert the processed second thermocouple sample 23 from below the stage 5 into the second slider 19, so that the smaller diameter section of the second thermocouple sample 23 protrudes from above the second slider 19, and the larger diameter section of the second thermocouple sample 23 is inserted into the second sample mounting slot 20;

[0043] Step 4: Adjust the area of ​​the large diameter section of the first thermocouple sample 22 exposed outside the first slider 16, and then tighten the first sample fixing screw 18; adjust the area of ​​the large diameter section of the second thermocouple sample 23 exposed outside the second slider 19, and then tighten the second sample fixing screw 21 until the ratio of the exposed areas of the large diameter sections of the first thermocouple sample 22 to the second thermocouple sample 23 reaches the set value.

[0044] Step 5: Adjust the position of the first slider 16 along the first slide 14, and at the same time adjust the position of the second slider 19 along the second slide 15 until the distance between the first electrode pair sample 22 and the second electrode pair sample 23 reaches the set value. Then, pass the second wire 35 and the third wire 36 through the cover plate 4 from below the cover plate 4, and then seal the wire through holes in the cover plate 4.

[0045] Step 6: Transfer the cover plate 4 from the temporary support to the reactor 3 and fix the cover plate 4 to the reactor 3 together. Then connect the second wire 35 and the third wire 36 to the electrochemical workstation 33. Then pour saturated potassium nitrate solution 30 into the beaker 29 so that the reference electrode 31 is immersed in the saturated potassium nitrate solution 30. At this time, the reference electrode 31 has been connected to the electrochemical workstation 33 in advance through the first wire 32.

[0046] Step 7: Insert one end of the prepared salt bridge tube 26 into the reactor 3 through the insertion hole on the cover plate 4, and insert the other end of the salt bridge tube 26 into the beaker 29 and immerse it in the saturated potassium nitrate solution 30. At this time, the inside of the salt bridge tube 26 has been filled with electrolyte solution.

[0047] Step 8: Prepare a funnel and insert the handle of the funnel into the reactor 3 through the insertion hole of the tail gas condenser pipe 37. Then, inject nitric acid 41 into the reactor 3 through the funnel until the injection amount of nitric acid 41 reaches the set value. Then remove the funnel and insert the tail gas condenser pipe 37 into the reactor 3 through the insertion hole on the cover plate 4. At this time, the tail gas condenser pipe 37 has been connected to the tail gas treatment equipment 38 beforehand, and the tail gas condenser pipe 37 is also fitted with a water-cooled heat exchange jacket 39 beforehand.

[0048] Step 9: Start the heating platform 2 through the control panel 6 to heat the nitric acid 41 inside the reactor 3 until the temperature of the nitric acid 41 reaches the set value. The temperature of the nitric acid 41 is fed back to the control panel 6 in real time through the temperature sensor 7. Then start the cooling circulating water station 40 to cool the tail gas condenser 37 through the water-cooled heat exchange jacket 39. Most of the tail gas condensate will drip back into the reactor 3 along the tail gas condenser 37, and a small part of the tail gas will enter the tail gas treatment equipment 38 for harmless treatment.

[0049] Step 10: After the nitric acid 41 reaches the set temperature, start the motor 12 through the control panel 6. The motor 12 drives the lead screw 8 to rotate synchronously. The rotational motion of the lead screw 8 will be converted into the linear motion of the lead screw 9. Then, the lead screw 9 drives the stage 5 to adjust its height. By adjusting the height of the stage 5, the first galvanic couple sample 22 and the second galvanic couple sample 23 can be tested for galvanic corrosion in gas phase, liquid phase or gas-liquid two-phase alternating state.

[0050] Step 11: Repeat steps 1 to 10, except that the setting value of the ratio of the exposed area of ​​the large diameter section of the first electrode pair sample 22 to the second electrode pair sample 23 is adjusted, the setting value of the electrode pair spacing of the first electrode pair sample 22 and the second electrode pair sample 23 is adjusted, and the setting value of the heating temperature of nitric acid 41 is adjusted.

[0051] In addition, in order to increase the number of thermocouple pairs tested in a single test, the number of stages 5 can be expanded as needed. For example, multiple stages 5 can be set along the lead screw 8 and guide rod 10, so as to meet the testing needs of multiple thermocouple pairs.

[0052] The solutions described in the embodiments are not intended to limit the scope of patent protection of this invention. All equivalent implementations or modifications that do not depart from the scope of this invention are included in the patent scope of this case.

Claims

1. A simulated spent fuel reprocessing boiling nitric acid galvanic corrosion testing device, characterized in that: The system includes a base, a heating platform, a reaction vessel, a cover plate, a platform, a lifting and adjusting mechanism, and a control panel. The heating platform is positioned above the base. The reaction vessel is positioned above the heating platform. The cover plate is positioned above the reaction vessel. The platform is located inside the reaction vessel and is connected to the cover plate via the lifting and adjusting mechanism. The control panel is mounted on the base, and the heating platform is electrically connected to the control panel. A temperature sensor is installed inside the reaction vessel and is electrically connected to the control panel. The lifting and adjusting mechanism includes a lead screw, a lead nut, a guide rod, a coupling, and a motor. The platform has a disc-shaped structure. The lead nut is fixed... The motor is fixedly installed at the center of the platform; it is vertically fixed above the cover plate with its shaft facing downwards; the lead screw is vertically arranged, with its upper end sealed through the cover plate and fixedly connected to the motor shaft via a coupling; the lead screw nut is fitted onto the lead screw; the guide rod is located on the side of the lead screw, parallel to the lead screw, and its top end is fixedly connected to the cover plate; a guide hole is provided on the platform, through which the guide rod passes; the motor is electrically connected to the control panel; a first slide rail and a second slide rail are provided on the platform, parallel to each other; a first slider is installed in the first slide rail. A first sample mounting groove is provided at the center of the bottom of the slider, and a first adapter hole is opened at the center of the interior of the first slider above the first sample mounting groove; a first sample fastening screw is installed on the side of the first sample mounting groove; a second slider is installed in the second slide, and a second sample mounting groove is provided at the center of the bottom of the second slider, and a second adapter hole is opened at the center of the interior of the second slider above the second sample mounting groove; a second sample fastening screw is installed on the side of the second sample mounting groove; the first sample mounting groove and the first adapter hole form a two-stage stepped hole structure, and the first thermocouple uses a two-stage... The first thermocouple pair has a stepped cylindrical structure. The large-diameter section of the first thermocouple pair is sealed and inserted into the first sample mounting groove, and the small-diameter section of the first thermocouple pair is sealed and inserted into the first adapter through-hole. A first protective sleeve covers the small-diameter section of the first thermocouple pair. The second sample mounting groove and the second adapter through-hole form a two-stage stepped hole structure. The second thermocouple pair also has a two-stage stepped cylindrical structure. The large-diameter section of the second thermocouple pair is sealed and inserted into the second sample mounting groove, and the small-diameter section of the second thermocouple pair is sealed and inserted into the second adapter through-hole. A second protective sleeve covers the small-diameter section of the second thermocouple pair.

2. The simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion testing device according to claim 1, characterized in that: A salt bridge tube is sealed and inserted into the cover plate. The salt bridge tube has a liquid injection port in the middle of its body, and a sealing plug is installed at the injection port. A first porous plug is installed at the opening of the salt bridge tube inside the reactor. A beaker is located outside the reactor and is used to store a saturated potassium nitrate solution. A reference electrode is installed inside the beaker and is electrically connected to an electrochemical workstation via a first wire. A second porous plug is installed at the opening of the salt bridge tube outside the reactor, and the opening of the salt bridge tube with the second porous plug is located inside the beaker. The top of the small-diameter section of the first thermocouple is electrically connected to the electrochemical workstation via a second wire, and the perforations of the second wire with the first protective sleeve and the cover plate are sealed. The top of the small-diameter section of the second thermocouple is electrically connected to the electrochemical workstation via a third wire, and the perforations of the third wire with the second protective sleeve and the cover plate are sealed.

3. The simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion testing device according to claim 2, characterized in that: A tail gas condenser is sealed and inserted into the cover plate. One end of the tail gas condenser is connected to the inside of the reactor, and the other end is connected to the tail gas treatment equipment. A water-cooled heat exchange jacket is adjusted on the body of the tail gas condenser and is connected to the refrigeration circulating water station.

4. A simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test method, employing the simulated spent fuel reprocessing boiling nitric acid galvanic galvanic corrosion test apparatus as described in claim 3, characterized in that... Includes the following steps: Step 1: Prepare a temporary support and fix the cover plate horizontally on the temporary support. At this time, the cover plate is pre-installed with a lifting and adjusting mechanism, the lifting and adjusting mechanism is pre-installed with a platform, and the platform is pre-installed with a first slider and a second slider. Step 2: Weld a second wire to the top of the small-diameter section of the first thermocouple sample, then pass the first protective sleeve through the second wire and cover the outside of the small-diameter section of the first thermocouple sample, and then seal the wire perforation of the first protective sleeve; at the same time, weld a third wire to the top of the small-diameter section of the second thermocouple sample, then pass the second protective sleeve through the third wire and cover the outside of the small-diameter section of the second thermocouple sample, and then seal the wire perforation of the second protective sleeve. Step 3: Insert the processed first thermocouple sample into the first slider from below the stage, so that the smaller diameter section of the first thermocouple sample protrudes from above the first slider, and the larger diameter section of the first thermocouple sample is inserted into the first sample mounting slot; at the same time, insert the processed second thermocouple sample into the second slider from below the stage, so that the smaller diameter section of the second thermocouple sample protrudes from above the second slider, and the larger diameter section of the second thermocouple sample is inserted into the second sample mounting slot. Step 4: Adjust the area of ​​the large diameter section of the first thermocouple sample exposed outside the first slider, and then tighten the first sample fixing screw; adjust the area of ​​the large diameter section of the second thermocouple sample exposed outside the second slider, and then tighten the second sample fixing screw until the ratio of the exposed area of ​​the large diameter section of the first thermocouple sample to that of the second thermocouple sample reaches the set value. Step 5: Adjust the position of the first slider along the first slide rail, and at the same time adjust the position of the second slider along the second slide rail until the distance between the first and second thermocouple samples reaches the set value. Then, pass the second and third wires through the cover plate from below the cover plate, and then seal the wire holes in the cover plate. Step 6: Transfer the cover plate from the temporary support to the reactor and fix the cover plate to the reactor. Then connect the second and third wires to the electrochemical workstation. Then pour saturated potassium nitrate solution into the beaker so that the reference electrode is immersed in the saturated potassium nitrate solution. At this time, the reference electrode has been connected to the electrochemical workstation in advance through the first wire. Step 7: Insert one end of the prepared salt bridge tube into the reactor through the insertion hole on the cover plate, and insert the other end of the salt bridge tube into the beaker and immerse it in the saturated potassium nitrate solution. At this time, the inside of the salt bridge tube has been filled with electrolyte solution. Step 8: Prepare a funnel and insert the handle of the funnel into the reactor through the insertion hole of the tail gas condenser pipe. Then, inject nitric acid into the reactor through the funnel until the amount of nitric acid injected reaches the set value. Then remove the funnel and insert the tail gas condenser pipe into the reactor through the insertion hole on the cover plate. At this time, the tail gas condenser pipe has been connected to the tail gas treatment equipment in advance, and a water-cooled heat exchange jacket has also been installed on the outside of the tail gas condenser pipe in advance. Step 9: Start the heating platform through the control panel to heat the nitric acid inside the reactor until the temperature of the nitric acid reaches the set value. The temperature of the nitric acid is fed back to the control panel in real time through the temperature sensor. Then start the cooling circulating water station to cool the tail gas condenser through the water-cooled heat exchange jacket. Step 10: After the nitric acid reaches the set temperature, start the motor through the control panel. The motor drives the lead screw to rotate synchronously, and then the lead screw nut drives the stage to adjust the height. By adjusting the height of the stage, the first and second galvanic couple samples can be tested for galvanic corrosion in gas phase, liquid phase or gas-liquid two-phase alternating state. Step 11: Repeat steps 1 to 10, except that the setting values ​​for the ratio of the exposed area of ​​the large diameter section of the first electrode pair sample to that of the second electrode pair sample are adjusted, the setting values ​​for the electrode pair spacing of the first electrode pair sample and the second electrode pair sample are adjusted, and the setting values ​​for the nitric acid heating temperature are adjusted.

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