A device for measuring the interface of radioactive waste resin based on magnetostrictive liquid level gauge

Abstract

The present invention discloses a device for measuring the interface of radioactive waste resin based on a magnetostrictive level gauge. The device comprises a magnetostrictive level gauge comprising a water level float and a resin float; the device further comprises a traction device, a cable, and a lifting claw; the cable is connected to the traction device, and the lifting claw is fixed to the cable; the lifting claw is located below the resin float, and when the traction device drives the lifting claw upward via the cable, the resin float is lifted by the lifting claw; the device further comprises a housing and a control box, the meter head and traction device are both located within the housing, and both are connected to the control box for data communication. The device measures the interface of irradiated resin by combining the measurement principle of a magnetostrictive level gauge with a special float design and a dedicated lifting device, enabling simultaneous measurement of the liquid level and the resin / water interface height.

Description

Technical Field

[0001] The invention relates to the field of indicating or measuring the liquid level or the surface of flowing solid materials, and in particular to a device for measuring the interface of radioactive waste resin based on a magnetostrictive liquid level gauge. Background Art

[0002] As of September 30, 2020, there are 49 nuclear power units in operation in my country with an installed capacity of 51,027.16 MWe (rated installed capacity). Each 1,000 MW nuclear power unit generates approximately 5-10 million tons of electricity per year. 3 Waste resin is one of the main radioactive wastes from nuclear power plants. In my country, most of this waste resin is currently solidified with cement. However, due to its large volume expansion ratio and resulting high waste volume, this not only fails to meet the principle of waste minimization but also places a significant burden on subsequent management. During solidification, the resin volume in the metering tank must be precisely controlled to ensure that the ratio of resin, water, and cement meets the design standard. Therefore, measuring and controlling the resin volume is a crucial aspect of the solidification process.

[0003] Common methods for measuring solid-liquid or gas-solid interfaces in China include: float method, reflection method, and dielectric constant method.

[0004] Float Method: Because the density difference between water and resin is minimal, the float's equivalent density must be accurately measured. During the measurement process, the ratio of commonly dissolved impurities in water constantly changes. When the density is below 1 or above 1.06, the float will not be at the liquid interface, resulting in completely erroneous results. When the water density fluctuates between 1 and 1.06, the float is at the solid-liquid interface. However, due to the density change, the float's position relative to the interface also changes, and the magnitude of this change is proportional to the float's diameter. A 1% change in water density (from 1 to 1.01) results in an error of one-sixth of the float's diameter. Therefore, the float method is subject to significant errors and even reliability issues.

[0005] Reflection method: Light (ultrasound) is stationary above an interface. A pulse of light is emitted, which reflects off the interface. The time difference between the emission and return of the pulse can be measured to calculate the interface distance. Alternatively, the change in interface height can be calculated by measuring the change in height and the change in reflection angle. Due to the small size of the resin particles, the reflection is diffuse, and the reflection angle is uncertain (the reflection angle method is not applicable). The reflected light intensity is very small (and fluctuates greatly, even to the point where no light signal is present at the receiving element). Therefore, the reflection method has low reliability. Furthermore, the ultrasonic probe cannot be placed above the water surface, otherwise the water surface will reflect most of the sound signal. If the probe is submerged, the acoustic wedge of the ultrasonic transducer is made of engineering plastic and is easily damaged in a radioactive environment.

[0006] Dielectric constant method: The dielectric constants of water and resin are basically the same, and changes in dissolved impurities in water will cause large changes in the dielectric constant. Therefore, large errors will occur in both capacitance and microwave wave velocity measurements.

[0007] Because both the liquid level and the resin / water interface height need to be measured, conventional single-interface measuring instruments are no longer suitable. Furthermore, in such highly radioactive environments, any instrument failure is extremely difficult and expensive to repair, making interface measurement of radioactive waste resin a challenging task. Summary of the Invention

[0008] In view of this, the present invention provides a radioactive waste resin interface measurement device based on a magnetostrictive liquid level gauge, aiming to solve the problem in the prior art of inaccurate radioactive waste resin interface measurement and inability to simultaneously measure the liquid level and resin / water interface height.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A device for measuring the interface of radioactive waste resin based on a magnetostrictive liquid level gauge, comprising a magnetostrictive liquid level gauge comprising a gauge head and a detection rod, the magnetostrictive liquid level gauge further comprising a water level float and a resin float, the water level float and the resin float both being slidably sleeved on the detection rod, with the water level float being located above the resin float;

[0011] The measuring device further includes a traction device, a cable, and a lifting claw; the cable is connected to the traction device, and the lifting claw is fixed to the cable; the lifting claw is located below the resin float, and when the traction device drives the lifting claw upward through the cable, the resin float is lifted by the lifting claw;

[0012] The measuring device further comprises a box body and a control box. The meter head and the traction device are both arranged in the box body, and the meter head and the traction device are both connected to the control box for data communication.

[0013] As a further technical solution of the above solution, the measuring device further includes a spring, the spring is sleeved on the detection rod and the upper end of the spring is fixedly connected to the box.

[0014] As a further technical solution of the above solution, the lifting claw includes a plurality of cutting claws.

[0015] As a further technical solution of the above solution, the cable is located in a gap between the resin float and the detection rod.

[0016] As a further technical solution of the above solution, a flange is fixedly connected to the bottom of the box.

[0017] As a further technical solution of the above solution, a heavy hammer is connected to the lower end of the detection rod.

[0018] As a further technical solution of the above solution, the resin float includes a shell and a counterweight block arranged in the shell.

[0019] As a further technical solution of the above solution, the shell is ellipsoidal.

[0020] As a further technical solution of the above scheme, the traction device includes an encoder, a motor, a first pulley and a second pulley; the encoder, the motor and the first pulley are all arranged in the box body, the first pulley is installed on the rotating shaft of the motor, the second pulley is arranged at the lower end of the detection rod, and the cable is wound between the first pulley and the second pulley; the encoder is connected to the motor, and the encoder and the motor are both connected to the control box for data communication.

[0021] As a further technical solution of the above solution, a radiation-proof compartment is provided in the box body, and the meter head, encoder and motor are all arranged in the radiation-proof compartment.

[0022] In summary, the present invention offers the following advantages and benefits compared to existing technologies: By combining the measurement principle of a magnetostrictive level gauge with a special float design and a dedicated lifting device, the present invention measures the irradiated resin interface, enabling simultaneous measurement of both the liquid level and the resin / water interface height. This environmentally friendly device, unmatched by other technical devices, features a high degree of automation, is easy to operate, provides excellent measurement results, and is safe and environmentally friendly. This device is highly competitive from both a technical and long-term economic perspective, potentially saving nuclear power plants substantial environmental pollution control costs and time. This provides a novel technology for measuring the interface of radioactive waste resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a front view structural schematic diagram of the present invention.

[0024] Figure 2 for Figure 1 The schematic diagram of the cross-section mechanism along the AA direction is shown. To clearly show the structure, the water level float and resin float are omitted.

[0025] Figure 3 for Figure 1 Schematic diagram of the top view structure.

[0026] The meanings of the numbers in the figure are: box 101, mounting plate 102, partition 103, cable gland 104, flange 105, spring 106, radiation-proof compartment 107, encoder 201, motor 202, first pulley 203, cable 204, lifting claw 205, detection rod 301, water level float 302, resin float 303, and weight 304. DETAILED DESCRIPTION

[0027] 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.

[0028] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0029] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of terms such as "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0030] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0031] like Figure 1-Figure 3As shown, a device for measuring the interface of radioactive waste resin based on a magnetostrictive level gauge according to an embodiment of the present application includes a magnetostrictive level gauge, which includes a gauge head and a probe rod 301. The magnetostrictive level gauge also includes a water level float 302 and a resin float 303. The water level float 302 and the resin float 303 are both slidably mounted on the probe rod 301, with the water level float 302 positioned above the resin float 303. The measuring device also includes a traction device, a cable 204, and a lifting claw 205. The cable 204 is connected to the traction device, and the lifting claw 205 is fixed to the cable 204. The lifting claw 205 is positioned below the resin float 303. When the traction device drives the lifting claw 205 upward via the cable 204, the resin float 303 is lifted by the lifting claw 205. The measuring device further includes a box body 101 and a control box. The meter head and the traction device are both arranged in the box body 101, and the meter head and the traction device are both connected to the control box for data communication.

[0032] A magnetostrictive level gauge is a magnetostrictive liquid level displacement sensor. A float is mounted on the outer surface of the sensor stem, moving up and down along the stem in response to changes in the liquid level. Inside the float is a permanent magnet ring. When the magnetic field of a pulsed current meets the magnetic field generated by the float ring, the magnetic field around the float changes, causing a waveguide made of magnetostrictive material to generate a torsional pulse at the float's location. This pulse travels back along the waveguide at a constant speed and is detected by a detector. By measuring the time difference between the pulse current and the torsional pulse, the float's position, and therefore the liquid level, can be precisely determined. Technical advantages of magnetostrictive level gauges: They are suitable for high-precision level measurement of clean liquids, achieving an accuracy of 1 mm, with the latest models achieving 0.1 mm. They can also be used to measure the interface between two dissimilar liquids. Their explosion-proof design makes them suitable for hazardous environments, and their intelligent electronic circuitry calculates volume. With the float as the only moving part, they require minimal maintenance. The embodiments of the present application utilize this principle to create a device for measuring the interface of radioactive waste resin. The measurement performance of this measuring device is primarily guaranteed by a magnetostrictive level gauge. A specially designed resin float 303 precisely suspends and remains at the interface between the resin and water. The magnetic ring within the resin float 303 acts on the probe rod 301, transmitting a position signal to the meter, which analyzes and processes the signal to calculate the resin interface value. Simultaneously, the water level float 302, suspended above the water surface, also emits a measurement signal, measuring the distance to the water surface. This allows a single instrument to simultaneously measure the height of the resin interface and the water surface. Since radioactive waste resin may become hardened after a period of quiescence, and particles trapped between the resin float 303 and the probe rod 301 or cable 204 may jam the resin float 303, rendering it impossible to measure. Therefore, the embodiment of the present application also specially designs a lifting device. When the resin float 303 is stuck, the resin float 303 is lifted to a certain height through the traction device, cable 204 and lifting claw 205, thereby destroying the fixed state between the resin float 303 and the detection rod 301, and allowing the resin float 303 to return to a state where it can slide freely relative to the detection rod 301.

[0033] To lower the lifted resin float 303 back to its original measuring position, the measuring device described in this embodiment of the present application further includes a spring 106, which is sleeved onto the probe rod 301 and fixedly connected to the housing 101 at its upper end. When the resin float 303 is lifted to a certain height by the lifting claw 205, it squeezes the water level float 302 and spring 106. The spring 106 then provides a restoring force, causing the water level float 302 and the resin float 303 to descend. Due to their inherent density, the water level float 302 and the resin float 303 automatically float to the water surface and the interface between the water surface and the resin. The lifting claw 205, driven by the traction device, then lowers the cable 204 below the resin float 303. By lifting and pressing back and forth several times, the gap between the resin float 303 and the detection rod 301 is no longer filled with resin, so that the resin float 303 can be restored to a state where it can slide freely relative to the detection rod 301, thereby ensuring the measurement effect.

[0034] If the resin is severely compacted, simply moving the resin float 303 up and down may not maintain a clear gap for a long time. To this end, the lifting claws 205 in the embodiment of the present application also include several cutting claws designed as blade claws. When the resin is severely compacted or stuck, the blade claw lifting device can cut the resin, thereby achieving the purpose of moving the resin float 303. Furthermore, the lifting claws 205 of the lifting device are designed as blade structures. When the claws sink into the resin, they can also cut the resin to achieve the purpose of lifting, reducing the failure rate of the device lifting.

[0035] In order to better lift the resin float 303 and effectively crush the compacted resin in the gap, the cable 204 is located in the gap between the resin float 303 and the detection rod 301. In this way, the cable 204 itself can also rub and crush the resin, while also reducing the volume of the embodiment of the application.

[0036] Furthermore, a weight 304 is connected to the lower end of the detection rod 301. The weight 304 is suspended to the end of the detection rod 301, and gravity causes the detection rod 301 to always remain in a vertical state to ensure measurement accuracy.

[0037] The design of the resin float 303 must consider the gap between the cable 204 or probe rod 301 and the resin float 303. This gap is currently designed to be greater than 2.5 times the diameter of the resin particles. Its clogging resistance needs to be repeatedly verified through subsequent testing to maximize its clogging resistance while ensuring measurement accuracy. The cable 204 itself has a very small diameter and does not affect the gap space.

[0038] Furthermore, the resin float 303 in this embodiment is designed as an adjustable-density float, comprising an outer shell and a counterweight disposed within the shell. During testing, the density of the resin float 303 can be continuously adjusted by adjusting the counterweight level, and different counterweights can be used for coarse and fine tuning to achieve the optimal measured density. Furthermore, the outer shell is ellipsoidal, or disc-shaped, allowing the counterweights within the shell to be dispersed as much as possible and concentrated at the bottom, resulting in a more uniform equivalent density throughout the resin float 303 and ensuring a stable suspension state.

[0039] In order to facilitate the installation of the device, a flange 105 is fixedly connected to the bottom of the box body 101 to facilitate the installation and connection of a storage tank containing radioactive waste resin.

[0040] To ensure smooth lifting of the resin float 303, the traction device includes an encoder 201, a motor 202, a first pulley 203, and a second pulley. The encoder 201, motor 202, and first pulley 203 are all located within the housing 101. The first pulley 203 is mounted on the rotating shaft of the motor 202, and the second pulley is located at the lower end of the detection rod 301. The cable 204 is wound between the first pulley 203 and the second pulley. The encoder 201 is connected to the motor 202, and both the encoder 201 and the motor 202 are connected to the control box for data communication. Specifically, the encoder 201 and the motor 202 are fixedly mounted within the housing 101 via a mounting plate 102. The motor 202 drives the first pulley 203 and the second pulley to rotate, allowing the cable 204 to move back and forth around the first pulley 203 and the second pulley.

[0041] Since radioactive waste resin has strong radiation ability and can easily affect the operation of electronic equipment, the embodiment of the present application also separates a radiation-proof compartment 107 in the box 101 through a partition 103. The meter head, encoder 201 and motor 202 are all arranged in the radiation-proof compartment 107 to isolate the impact of radiation on electronic equipment.

[0042] The entire device is operated and controlled by a remote control box. A cable gland 104 is provided on the box 101, connecting the box 101 and the control box via a cable. This ensures that the control box is shielded from radiation and protects the operator's safety. Other critical parts of the device that may be affected by radiation, such as the walls of the radiation-proof compartment 107, can be made of shielding materials such as lead to ensure measurement accuracy. However, it is not advisable to use lead for all components, as this would significantly increase the total weight of the device.

[0043] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0044] The above preferred embodiments should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for measuring the interface of radioactive waste resin based on a magnetostrictive liquid level gauge, comprising a magnetostrictive liquid level gauge, wherein the magnetostrictive liquid level gauge comprises a meter head and a detection rod (301), and is characterized in that: The magnetostrictive liquid level gauge further comprises a water level float (302) and a resin float (303), wherein the water level float (302) and the resin float (303) are both slidably mounted on the detection rod (301), and the water level float (302) is located above the resin float (303); The measuring device further comprises a traction device, a cable (204) and a lifting claw (205); the cable (204) is connected to the traction device, and the lifting claw (205) is fixed on the cable (204); the lifting claw (205) is located below the resin float (303), and when the traction device drives the lifting claw (205) to rise through the cable (204), the resin float (303) is lifted by the lifting claw (205); The measuring device further comprises a box (101) and a control box. The meter head and the traction device are both arranged in the box (101), and the meter head and the traction device are both connected to the control box for data communication.

2. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The measuring device further comprises a spring (106), wherein the spring (106) is sleeved on the detection rod (301) and the upper end of the spring (106) is fixedly connected to the box (101).

3. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The lifting claw (205) includes a plurality of cutting claws.

4. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The cable (204) is located in the gap between the resin float (303) and the detection rod (301).

5. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: A flange (105) is fixedly connected to the bottom of the box body (101).

6. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The lower end of the detection rod (301) is connected to a weight (304).

7. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The resin float (303) comprises a shell and a counterweight block arranged in the shell.

8. The device for measuring the interface of radioactive waste resin based on a magnetostrictive liquid level gauge according to claim 7, characterized in that: The shell is in an ellipsoidal shape.

9. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 1, characterized in that: The traction device comprises an encoder (201), a motor (202), a first pulley (203) and a second pulley; the encoder (201), the motor (202) and the first pulley (203) are all arranged in the box body (101), the first pulley (203) is installed on the rotating shaft of the motor (202), the second pulley is arranged at the lower end of the detection rod (301), and the cable (204) is wound between the first pulley (203) and the second pulley; the encoder (201) is connected to the motor (202), and the encoder (201) and the motor (202) are both connected to the control box for data communication.

10. The radioactive waste resin interface measuring device based on a magnetostrictive liquid level gauge according to claim 9, characterized in that: A radiation-proof compartment (107) is provided in the box (101), and the meter head, encoder (201) and motor (202) are all arranged in the radiation-proof compartment (107).

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