CN217333645U - High-burnup fuel cladding oxidation test device - Google Patents

Abstract

The utility model relates to a high-burnup fuel cladding oxidation test device, including electric melting furnace, air supply line subassembly, waste liquid recovery system and shield cover. The gas supply pipe assembly includes a water vapor supply pipe connected to a first end of the electric melter in a first direction. The waste liquid recovery system is connected with the second end of the electric melting furnace along the first direction. The shield cover, the electric melting furnace, the gas supply pipe assembly and the waste liquid recovery system are arranged in the shield cover. The cladding sample piece is arranged in the electric melting furnace, and water vapor can be introduced into the electric melting furnace through the water vapor supply pipe, so that the cladding sample piece and the water vapor are subjected to oxidation reaction under the heating of the electric melting furnace. Since the water vapor is also radioactive after flowing through the containment sample, the radioactive recovery unit is provided so that the radioactive material carried in the waste fluid can be absorbed, thereby preventing radioactive contamination of the waste fluid. Meanwhile, the shielding cover wraps the electric melting furnace, the gas supply pipe assembly and the waste liquid recovery system, and can shield possible radiation generated by the cladding sample piece.

Description

High-burnup fuel cladding oxidation test device

Technical Field

The utility model relates to a cladding oxidation test device technical field especially relates to a high fuel consumption fuel cladding oxidation test device.

Background

The reactor coolant loss accident, referred to as loss of coolant accident or LOCA for short, refers to an accident in which the primary circuit coolant charge is reduced due to a rupture (break) of the primary circuit pressure boundary. After a LOCA accident occurs, as the coolant volume of the reactor pressure vessel decreases, core fuel may be exposed, causing the fuel clad to heat up. The zirconium based cladding materials (e.g., Zr-2, Zr-4, ZIRLO, M5, E110, etc.) undergo steam oxidation, i.e., a zirconium water reaction, at high temperatures. The existing LOCA acceptance criteria 10CFR50.46 contains 5 independent limits or requirements: (1) the fuel clad peak temperature (PCT) should not exceed 1204 ℃ (2200 ° f); (2) the local maximum oxidation amount of the fuel cladding (equivalent cladding oxidation amount ECR) should not exceed 17% of the pre-oxidation cladding thickness; (3) the amount of hydrogen produced by the reaction of the fuel clad with water or steam should not exceed 1% of the total amount of hydrogen produced by the reaction of all the fuel clad; (4) the core maintains a coolable geometry; (5) the core maintains long-term cooling.

However, the current LOCA acceptance criteria of 10CFR50.46 was developed based on LOCA performance tests of a large number of non-irradiated Zr-2 and Zr-4 alloys, and these criteria are not necessarily applicable to cladding materials under high burnup conditions. Under high burn-up conditions, hydrogen absorption embrittlement of the fuel cladding can occur, i.e. hydrogen produced by corrosion of the cladding during normal operation is absorbed by the cladding base metal. Under a LOCA accident, hydrogen in the cladding increases the solid solubility and diffusion rate of oxygen in the cladding. Thus, for high-burn-up fuel cladding with high hydrogen content, even if the peak cladding temperature is below 1204 ℃, the local maximum oxidation is less than 17%, the cladding material may still embrittle, losing ductility. Therefore, the performance of the cladding material under the LOCA condition under the high-fuel-consumption condition must be fully researched.

However, the prior art lacks a means for conducting a high-burn fuel cladding oxidation test.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide a high-burnup fuel cladding oxidation test device to solve the problem of the lack of a device for performing the high-burnup fuel cladding oxidation test in the prior art.

A high-burnup fuel cladding oxidation test apparatus, comprising:

the electric melting furnace is used for heating the cladding sample piece;

the gas supply pipe assembly comprises a water vapor supply pipe, is connected with a first end of the electric melting furnace along a first direction and is used for supplying water vapor required by an oxidation reaction to the cladding sample piece;

a waste liquid recovery system connected to a second end of the electric melter in the first direction, the waste liquid recovery system including a radioactivity recovery unit for recovering radioactive substances in the waste liquid discharged from the second end of the electric melter; and

and the electric melting furnace, the gas supply pipe assembly and the waste liquid recovery system are arranged in the shielding cover.

In one embodiment, the waste liquid recovery system further comprises a condenser and a waste liquid tank, wherein the inlet end of the condenser is connected with the second end of the electric melting furnace, the outlet end of the condenser is connected with the waste liquid tank, and the radioactivity recovery unit is connected with the waste liquid tank.

In one embodiment, the radioactivity recovery unit is an activated carbon adsorption unit.

In one embodiment, the gas pressure inside the shield is less than the gas pressure outside the shield.

In one embodiment, the electric melting furnace comprises an electric heating pipe and a pipe body, the electric heating pipe is arranged around the outside of the pipe body, and the size of the pipe body along the first direction is larger than that of the electric heating pipe along the first direction;

the high-fuel-consumption fuel cladding oxidation test device further comprises a moving mechanism, wherein the moving mechanism is arranged on the electric melting furnace and is used for driving the cladding sample piece to move in the pipe body along a first direction.

In one embodiment, the high burnup fuel cladding oxidation test device further comprises a quenching bath, the quenching bath is arranged at the first end of the electric melting furnace, and the quenching bath is communicated with the interior of the pipe body.

In one embodiment, the moving mechanism is a worm transmission mechanism, the worm transmission mechanism comprises a worm and a power mechanism, one end of the worm is used for connecting the cladding sample piece, and the power mechanism is used for driving the worm to move along the first direction.

In one embodiment, the electric melting furnace further comprises an outer support and an insulating layer, the electric heating pipe, the insulating layer and the outer support are sequentially arranged from inside to outside, and the electric heating pipe comprises a silicon carbide rod and/or a resistance heating rod.

In one embodiment, the gas supply pipe assembly further comprises an argon gas supply pipe connected to the first end of the electric melter for introducing argon gas into the electric melter.

In one embodiment, the high-burnup fuel cladding oxidation test device further comprises two groups of thermocouples, wherein one group of thermocouples is arranged on the cladding sample piece, and the other group of thermocouples is arranged in the electric smelting furnace.

According to the high-fuel-consumption fuel cladding oxidation test device, the electric melting furnace and the water vapor supply pipe are arranged, the cladding sample piece is arranged in the electric melting furnace, and water vapor is introduced into the electric melting furnace through the water vapor supply pipe, so that the cladding sample piece and the water vapor are subjected to oxidation reaction under the heating of the electric melting furnace. Since the highly combustible fuel cladding sample is radioactive after being irradiated in the stack, water vapor is also radioactive after flowing through the cladding sample, and by arranging the radioactivity recovery unit in the waste liquid recovery system, the radioactive substances carried in the waste liquid can be absorbed, so that the radioactive contamination of the waste liquid can be prevented. Meanwhile, the electric melting furnace, the gas supply pipe assembly and the waste liquid recovery system are wrapped by the shielding cover, so that radiation generated by the high-fuel-consumption fuel cladding sample piece in the test process can be shielded. Therefore, the performance of the cladding material under the LOCA working condition under the high-burnup working condition can be researched through the high-burnup fuel cladding oxidation test device.

Drawings

FIG. 1 is a schematic diagram of a high-burnup fuel cladding oxidation test apparatus in one embodiment;

FIG. 2 is a schematic view of the configuration of the jacket sample within the body of the tube.

Reference numerals:

100-an electric melting furnace; 120-an outer support; 130-an insulating layer; 140-an electric heating tube;

210-a water vapor supply pipe; 220-argon supply tube;

300-a waste liquid recovery system; 310-a condenser; 311-a housing; 312-spiral coil pipe; 320-a waste liquid tank; 330-a radioactivity recovery unit;

400-a shield can; 410-glove box;

500-a tube body; 510-a moving mechanism;

600-quenching bath;

700-cladding a sample; 710-inlet ends of water vapor flow channels; 720-outlet end of the water vapor flow channel;

800-thermocouple.

Detailed Description

In order to make the above objects, features and advantages of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, as those skilled in the art will be able to make similar modifications without departing from the spirit and scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, a first feature "on" or "under" a second feature may be directly contacting the second feature or the first and second features may be indirectly contacting the second feature through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, an embodiment of the present invention provides a high-burnup fuel cladding oxidation test apparatus, which includes an electric melter 100, a gas supply pipe assembly, a waste liquid recovery system 300, and a shield 400. The electric melter 100 is used to heat the cladding sample 700. The gas supply pipe assembly includes a water vapor supply pipe 210 connected to a first end of the electric melter 100 in a first direction for supplying water vapor required for an oxidation reaction to the shell sample 700, the water vapor being generated by a steam generator. The waste liquid recovery system 300 is connected to a second end of the electric melter 100 in the first direction, and the waste liquid recovery system 300 includes a radioactivity recovery unit for recovering radioactive materials in the waste liquid discharged from the second end of the electric melter 100. The shield case 400, the electric melter 100, the gas supply pipe assembly, and the waste liquid recovery system 300 are disposed inside the shield case 400.

In the present embodiment, the sheath sample 700 is provided in the electric melter 100 by providing the electric melter 100 and the water vapor supply pipe 210, and water vapor is introduced into the electric melter 100 through the water vapor supply pipe 210, so that the sheath sample 700 is subjected to an oxidation reaction with the water vapor under heating of the electric melter 100. Since the highly combustible fuel cladding sample 700 is radioactive by irradiation in the stack, and thus the water vapor is also radioactive after flowing through the cladding sample 700, the radioactive substance carried in the waste liquid can be absorbed by providing the radioactive recovery unit in the waste liquid recovery system 300, so that radioactive contamination of the waste liquid can be prevented. Meanwhile, the electric melter 100, the gas supply pipe assembly and the waste liquid recovery system 300 are wrapped by the shielding case 400, and radiation generated from the high-fuel-consumption fuel cladding sample 700 during the reaction process can be shielded. Therefore, the performance of the cladding material under the LOCA working condition under the high-burnup working condition can be researched through the high-burnup fuel cladding oxidation test device.

In some embodiments, the waste liquid recovery system 300 further includes a condenser 310 and a waste liquid tank 320, an inlet end of the condenser 310 is connected to the second end of the electric melter 100, an outlet end of the condenser 310 is connected to the waste liquid tank 320, and the radioactivity recovery unit is connected to the waste liquid tank 320.

In the present embodiment, the condenser 310 includes a housing 311, a spiral coil 312 disposed in the housing 311, and secondary-side condensate, wherein an inlet end of the spiral coil 312 is an inlet end of the condenser 310, and an outlet end of the spiral coil 312 is an outlet end of the condenser 310. Hydrogen gas generated in the zirconium water process or unreacted water vapor can enter the spiral coil 312 in the condenser 310 and undergo heat exchange with the secondary cooling water in the spiral coil 312, thereby cooling the water vapor to a liquid and then circulating to the waste liquid tank 320. The radioactivity recovery unit is connected with the waste liquid tank through a pipeline, and the radioactivity recovery unit can absorb radioactive substances carried in the waste gas.

Further, the radioactivity recovery unit is an activated carbon adsorption unit. And a radioactivity monitoring instrument is arranged on the active carbon adsorption unit and used for monitoring the radioactivity change of the active carbon adsorption unit.

In some embodiments, the air pressure inside the shielding can 400 is less than the air pressure outside the shielding can 400, i.e., the inside of the shielding can 400 is a negative pressure environment, which can be used to prevent the radioactive material from leaking during the test. In addition, the shield 400 may be made of a material for shielding radioactive materials. Preferably, the shielding case 400 is a lead glass case, which has a good shielding effect and can pass an observation test of the lead glass case. The lead glass cover is further provided with a glove box 410, and during testing, workers can insert hands into the glove box 410 to operate.

In some embodiments, the electric melter 100 includes a pipe body 500 and the electric heating pipe 140, the electric heating pipe 140 is enclosed outside the pipe body 500, and a dimension of the pipe body 500 in the first direction is larger than a dimension of the electric heating pipe 140 in the first direction. The number of the electric heating pipes 140 may be plural, and a plurality of electric heating pipes 140 are wound around the pipe body 500 in the circumferential direction. Wherein the first direction may be a height direction of the electric melter 100.

The high-fuel-consumption fuel cladding oxidation test device further comprises a moving mechanism 510, wherein the moving mechanism 510 is arranged on the electric melting furnace 100, and the moving mechanism 510 is used for driving the cladding sample 700 to move in the tube body 500 along the first direction.

In this embodiment, the tube body 500 may be a high temperature resistant quartz tube, and heat generated by the electric melter 100 is transmitted to the inner cladding sample 700 through the high temperature resistant quartz tube in a thermal radiation manner. In the process of performing the cladding oxidation test, the test is also needed to change the heating rate and the cooling rate so as to be used for carrying out the oxidation sensitivity test of the high-fuel-consumption fuel cladding material. Since the size of the pipe body 500 in the first direction is larger than the size of the electric heating pipe 140 in the first direction, when the moving mechanism 510 drives the cladding sample 700 to move to the height range of the electric heating pipe 140 after the heating is finished, the cladding sample 700 can only be cooled slowly due to the higher temperature in the electric melter 100. When the moving mechanism 510 drives the cladding sample 700 to move out of the height range of the electric heating tube 140, the cladding sample 700 can be rapidly cooled due to the low air temperature.

Further, the high-fuel-consumption fuel cladding oxidation test device further comprises a quenching bath 600, the quenching bath 600 is arranged at the first end of the electric melting furnace 100, and the quenching bath 600 is communicated with the interior of the electric melting furnace 100. That is, when the moving mechanism 510 moves the cladding sample 700 toward the first end of the electric melter 100 and the cladding sample 700 is located in the quenching bath, quenching cooling can be achieved.

In some embodiments, the moving mechanism 510 is a worm drive mechanism including a worm having one end for connecting to the cladding sample 700 and a power mechanism for moving the worm in a first direction. The power mechanism is fixed on the pipe body 500, and the worm moves relative to the power mechanism under the driving of the power mechanism. The worm transmission mechanism has good stability and high precision, and can ensure the accurate and stable movement of the cladding sample piece 700. And the worm drive mechanism does not interfere with other objects in the high-burnup fuel cladding oxidation test device.

In other embodiments, the moving mechanism 510 may also be a variety of telescoping mechanisms, such as an electric telescoping rod.

In some embodiments, the electric melting furnace 100 includes an outer support 120 and an insulating layer 130, the electric heating tube 140, the insulating layer and the outer support 120 are sequentially disposed from inside to outside, and the electric heating tube 140 includes a silicon carbide rod and/or a resistance heating rod. The outer support 120 serves as an outer shell of the electric melting furnace 100, and the insulating layer 130 is disposed between the outer support 120 and the electric heating tube 140, and is used for slowing down the dissipation speed of heat generated by the electric heating tube 140 to one side of the outer support 120.

In some of the present embodiments, the electrical heating tube 140 includes a silicon carbide rod and a resistance heating rod. Namely, the silicon carbide rod and the resistance heating rod are arranged at the same time, and the silicon carbide rod or the resistance heating rod can be selectively used in the test. For example, when rapid heating is required, a silicon carbide rod can be used for heating, the maximum heating temperature of the silicon carbide rod is 1300 ℃, the maximum heating rate is 30 ℃/s, and the test working condition requirement of high-temperature oxidation of the cladding material can be met. When the temperature needs to be raised slowly, a resistance heating rod can be used for heating.

Specifically, in an actual test, the slow heating and the fast heating in the embodiment can be combined with the fast cooling, the slow cooling and the quenching cooling in the above embodiment, so that the combination of the slow heating/slow cooling, the slow heating/fast cooling, the fast heating/slow cooling, the fast heating/fast cooling and the fast heating/quenching cooling can be obtained, and the combination can be used for verifying the influence of different heating and cooling condition combinations on the high-temperature oxidation performance of the high-fuel-consumption fuel cladding.

In some embodiments, the gas supply pipe assembly further comprises an argon gas supply pipe 220, and the argon gas supply pipe 220 is connected to the first end of the electric melter 100 for introducing argon gas into the electric melter 100. An end of the argon supply pipe 220 remote from the electric melter 100 is connected to the argon tank through a connection pipe. And is used for introducing argon gas into the tube body 500 at the beginning stage of the test so as to remove air in the tube body 500.

In some embodiments, the high-burnup fuel cladding oxidation test apparatus further comprises two sets of thermocouples 800, wherein one set of thermocouples 800 is arranged on the cladding sample 700 and the other set of thermocouples 800 is arranged in the electric melter 100.

Specifically, the thermocouple 800 disposed on the cladding sample 700 is used for monitoring the temperature of the cladding sample 700, and the thermocouple 800 disposed in the electric melter 100 is located in the tube 500 and between the cladding sample 700 and the inner wall of the tube 500, and is used for monitoring the ambient temperature of the cladding sample 700.

The high burnup fuel cladding oxidation test apparatus of the present application may also be used to perform single and double side oxidation tests on the cladding sample 700. Referring to fig. 2, the containment shell 700 is a cylindrical structure, and a water vapor flow channel is formed in the containment shell 700, wherein an inlet end 710 of the water vapor flow channel is located at one end of the cylindrical structure, and an outlet end 720 of the water vapor flow channel is located on a sidewall of the cylindrical structure and is close to the other end of the cylindrical structure. When a single-sided oxidation test is carried out, the inlet end and the outlet end need to be plugged. In the double-sided oxidation test, the inlet and outlet ends need to be opened.

In the high-burnup fuel cladding oxidation test, the moving mechanism 510 is first actuated to feed the cladding sample 700 into the electric melter 100, and argon gas is supplied to the electric melter 100 through the argon gas supply pipe 220 to purge air in the test apparatus. Then, the electric heating pipe 140 of the electric melting furnace 100 is opened to heat the cladding sample 700, argon gas is heated to 150 ℃, and then water vapor of 150 ℃ is introduced into the electric melting furnace 100. The heating is continued to keep the cladding sample 700 at the temperature required by the test (generally 800-1200 ℃). The electric heating tube 140 may use a silicon carbide rod heater or a resistance heater as needed to perform the simulation of the fast heating or slow heating condition, respectively. Meanwhile, the water vapor and the argon gas flow out of the tube 500 and enter the condenser 310, and the water vapor flows into the waste liquid tank 320 after being condensed. An activated carbon adsorption unit connected to the waste liquid tank 320 adsorbs radioactive substances that may be carried by the water vapor and argon gas. And finally, closing the electric heating tube 140 after the cladding sample piece 700 is oxidized at high temperature. By the moving mechanism 510, the cladding sample 700 can be placed in the height range of the electric heating tube 140 for slow cooling, placed outside the height range of the electric heating tube 140 for fast cooling, or placed in the quenching bath 600 for quenching cooling, so as to research the influence of different cooling rates on the oxidation performance of the high-fuel-consumption fuel cladding. During the test, the dynamic change of the temperature of the thermocouple 800 is recorded in real time. After the test is finished, the cladding sample piece 700 is taken down, oxidation weighing is carried out, and follow-up tests such as a ring crush test and the like are continuously carried out.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. A high-burnup fuel cladding oxidation test apparatus, comprising:

the electric melting furnace is used for heating the cladding sample piece;

the gas supply pipe assembly comprises a water vapor supply pipe, is connected with a first end of the electric melting furnace along a first direction and is used for supplying water vapor required by an oxidation reaction to the cladding sample piece;

a waste liquid recovery system connected to a second end of the electric melter in the first direction, the waste liquid recovery system including a radioactivity recovery unit for recovering radioactive substances in waste vapor discharged from the second end of the electric melter; and

and the electric melting furnace, the gas supply pipe assembly and the waste liquid recovery system are arranged in the shielding cover.

2. The high-burnup fuel cladding oxidation test apparatus of claim 1, wherein the waste liquid recovery system further includes a condenser and a waste liquid tank, an inlet end of the condenser is connected to the second end of the electric melter, an outlet end of the condenser is connected to the waste liquid tank, and the radioactivity recovery unit is connected to the waste liquid tank.

3. The high burnup fuel cladding oxidation test apparatus of claim 1, wherein the radioactivity recovery unit is an activated carbon adsorption unit.

4. The high burnup fuel cladding oxidation test apparatus of claim 1, wherein a gas pressure inside the shield is less than a gas pressure outside the shield.

5. The high-burnable fuel cladding oxidation test apparatus of claim 1, wherein the electric melter includes an electric heating tube and a tube body, the electric heating tube being surrounded outside the tube body, a dimension of the tube body in the first direction being larger than a dimension of the electric heating tube in the first direction;

the high-fuel-consumption fuel cladding oxidation test device further comprises a moving mechanism, the moving mechanism is arranged on the electric melting furnace, and the moving mechanism is used for driving the cladding sample piece to move in the pipe body along a first direction.

6. The high-burnable fuel cladding oxidation test apparatus as set forth in claim 5, further comprising a quenching bath provided at the first end of the electric melter, the quenching bath communicating with the inside of the pipe body.

7. The high-burnup fuel cladding oxidation test device of claim 5, wherein the moving mechanism is a worm transmission mechanism, the worm transmission mechanism includes a worm and a power mechanism, one end of the worm is used for connecting the cladding sample, and the power mechanism is used for driving the worm to move along a first direction.

8. The high burnup fuel cladding oxidation test device of claim 5, wherein the electric melter further comprises an outer support body and an insulating layer, the electric heating pipe, the insulating layer and the outer support body are sequentially arranged from inside to outside, and the electric heating pipe comprises a silicon carbide rod and/or a resistance heating rod.

9. The high burnup fuel clad oxidation test apparatus of claim 1, wherein the gas supply tube assembly further comprises an argon gas supply tube connected to the first end of the electric melter for introducing argon gas into the electric melter.

10. The high burnup fuel cladding oxidation test apparatus of claim 9, further comprising two sets of thermocouples, one set of thermocouples being disposed on the cladding sample and the other set of thermocouples being disposed within the electric melter.

Images