Spent fuel assembly disassembly cutter performance evaluation device and evaluation method

Abstract

A kind of spent fuel assembly disassembly cutter performance evaluation device and evaluation method, for the sawing machinability of nuclear grade material of irradiated spent fuel assembly in dry condition without lubrication is carried out system test and quantitative evaluation, the device includes: main test table, including main rack, main work platform, main drive mechanism, transverse drive mechanism, vertical drive mechanism, cutter and spent fuel assembly clamp, cutter is connected with main drive mechanism;Sub-test table is set in the side of main rack corresponding to main drive mechanism;And control system, for controlling main drive mechanism, transverse drive mechanism and vertical drive mechanism, and real-time detection torque, current, vibration, noise and cutter temperature of main drive mechanism output, real-time monitoring cutter tooth wear and the cutting topography of being cut object, collect and store test data, and construct dry sawing reliability feature database.The present application also provides spent fuel assembly disassembly cutter performance evaluation method.

Description

Technical Field

[0001] This invention relates to nuclear fuel cycle reprocessing technology, and in particular to an evaluation device and method for evaluating the performance of sawing tools during the dismantling of spent fuel assemblies. Background Technology

[0002] With the development of fast reactors and closed fuel cycles, the dismantling of spent fuel assemblies has become a bottleneck in reprocessing plants. The assembly shell is made of 3mm thick PNC-FMS or ODS steel, which undergoes significant hardening and work hardening after irradiation, and must be cut under uncooled and unlubricated conditions in a hot chamber. Existing technologies, such as abrasive wheel cutting, generate large amounts of radioactive waste liquid; laser cutting suffers from slag adhesion and significant thermal impact on fuel rods; mechanical sawing fails to meet the industrial specifications of "long life, high speed, and zero breakage" due to difficulties in chip removal and rapid tool wear. Currently, there is a lack of a dedicated evaluation platform for the cutting performance of spent fuel assembly dismantling tools, which prevents the provision of quantitative basis for material selection, geometric parameters, coating design, and process optimization of dismantling tools, severely hindering the engineering progress of spent fuel assembly dismantling equipment. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a device and method for evaluating the performance of spent fuel assembly dismantling tools, which addresses the above-mentioned deficiencies of the prior art.

[0004] To achieve the above objectives, the present invention provides a performance evaluation device for spent fuel assembly dismantling tools, wherein the device is used for systematic testing and quantitative evaluation of the sawing machinability of nuclear-grade materials of irradiated spent fuel assemblies under dry, unlubricated conditions, including:

[0005] The main test bench includes a main frame, a main working platform, a main drive mechanism, a lateral drive mechanism, a vertical drive mechanism, a cutting tool, and a spent fuel assembly fixture. The main working platform is mounted on the main frame, and a main T-slot test bench is provided on the main working platform. The vertical drive mechanism is mounted on the main working platform via a Z-axis support frame. The lateral drive mechanism is located on the main working platform and connected to the main drive mechanism. The main drive mechanism is mounted on the Z-axis support frame and connected to the vertical drive mechanism. The cutting tool is connected to the main drive mechanism. The spent fuel assembly fixture is provided corresponding to the T-slot test bench.

[0006] A secondary test bench, located on one side of the main frame corresponding to the main drive mechanism, includes a secondary frame and a secondary working platform mounted on the secondary frame. A secondary T-slot test bench is mounted on the secondary working platform, and the secondary T-slot test bench is perpendicular to the T-slot test bench.

[0007] The control system is connected to the main drive mechanism, the lateral drive mechanism and the vertical drive mechanism respectively. It is used to control the main drive mechanism, the lateral drive mechanism and the vertical drive mechanism, and to detect the torque, current, vibration, noise and tool temperature output by the main drive mechanism in real time. It also monitors the wear of the tool teeth and the cutting morphology of the object being cut in real time, collects and stores test data, and constructs a dry sawing reliability characteristic database.

[0008] The aforementioned spent fuel assembly dismantling tool performance evaluation device includes a main drive mechanism comprising a rotary spindle, a spindle drive motor, and a spindle reducer. The spindle reducer is connected to the spindle drive motor. The spindle is mounted on a spindle bearing housing and connected to the spindle reducer via a spindle coupling. The tool is mounted on the spindle bearing housing via a Morse taper tool holder and is connected to the spindle.

[0009] The aforementioned spent fuel assembly dismantling tool performance evaluation device, wherein the output speed of the spindle drive motor is 20-6000 rpm, to adapt to high-speed and low-speed cutting of different types of tools.

[0010] The aforementioned spent fuel assembly dismantling tool performance evaluation device, wherein the tool is a metal circular saw, ceramic saw teeth or CBN saw blade, is used to systematically test and quantitatively evaluate the machinability of irradiated stainless steel cladding, end plugs and skeleton for circumferential cutting, longitudinal cutting and cutting.

[0011] The aforementioned spent fuel assembly dismantling tool performance evaluation device includes a control system comprising an industrial computer and a torque sensor, a current sensor, a decibel meter, an acceleration sensor, a temperature sensor, and a high-speed camera connected to the industrial computer. The torque sensor and current sensor are mounted on the spindle drive motor; the acceleration sensor, decibel meter, and temperature sensor are mounted on the spindle bearing housing; and the high-speed camera is positioned corresponding to the tool.

[0012] The aforementioned spent fuel assembly dismantling tool performance evaluation device includes a control system that further comprises a pneumatic vortex tube cooler, which is mounted on the Z-axis support and connected to the industrial control computer. The gas pressure of the pneumatic vortex tube cooler is continuously adjustable from 0 to 0.5 MPa, and it cools the tool and accelerates chip removal according to the test requirements.

[0013] The aforementioned spent fuel assembly dismantling tool performance evaluation device includes a transverse drive mechanism comprising an X-axis drive motor, an X-axis reducer, an X-axis lead screw and nut, and an X-axis linear guide. The X-axis reducer is connected to the X-axis drive motor. The X-axis lead screw and nut are mounted on the main working platform via an X-axis bearing seat and connected to the X-axis reducer via an X-axis coupling. The X-axis linear guide is arranged parallel to the X-axis lead screw and nut on the main working platform and is connected to the Z-axis support frame.

[0014] The aforementioned spent fuel assembly dismantling tool performance evaluation device includes a vertical drive mechanism comprising a Z-axis drive motor, a Z-axis reducer, a Z-axis lead screw and nut, and a Z-axis linear guide. The Z-axis reducer is connected to the Z-axis drive motor and mounted on the Z-axis support frame. The Z-axis lead screw and nut are mounted on the Z-axis support frame via a Z-axis bearing seat and are connected to the Z-axis reducer via a Z-axis coupling. The Z-axis support frame is connected to the X-axis lead screw and nut and moves along the X-axis linear guide at a speed of 0-1000 mm / min.

[0015] In the aforementioned spent fuel assembly dismantling tool performance evaluation device, the main drive mechanism is connected to the Z-axis lead screw and moves along the Z-axis linear guide at a speed of 0-200 mm / min. The control system determines the optimal cutting depth by adjusting the main drive mechanism to move forward or backward along the Z-axis, accurately judges the cutting performance of the tool, quickly maps the optimal cutting parameter range, and switches between circumferential cutting, slitting, or longitudinal cutting conditions.

[0016] To better achieve the above objectives, the present invention also provides a method for evaluating the performance of spent fuel assembly dismantling tools, wherein the aforementioned spent fuel assembly dismantling tool performance evaluation device includes the following steps:

[0017] Fix the tool to be tested to the rotating spindle;

[0018] The spent fuel assembly to be cut is fixed to the main test bench using a spent fuel assembly clamp; during circumferential cutting and slit cutting, the axis of the spent fuel assembly is perpendicular to the rotation plane of the cutting tool; during longitudinal cutting, the axis of the spent fuel assembly is parallel to the rotation plane of the cutting tool.

[0019] The control system sets the corresponding cutting speed and feed rate according to the circumferential cutting, longitudinal cutting, or slit cutting conditions; and performs tool setting confirmation, moving the tool to a position where it is just out of contact with the material to be cut;

[0020] Start the blade rotation to begin the cutting performance evaluation test of the blade dry cutting the spent fuel assembly;

[0021] During the experiment, the control system automatically collected and recorded the spindle drive motor torque, spindle drive motor current, and tool temperature in real time, and generated curves showing the changes of spindle drive motor torque, spindle drive motor current, vibration and noise generated during cutting, and tool temperature over time; and

[0022] By combining images of saw blade tooth wear and cut morphology of the object being cut, the cutting performance of dry sawing of spent fuel assemblies is evaluated, and a database of dry sawing reliability characteristics is constructed.

[0023] The technical effects of this invention are as follows:

[0024] This invention is applicable to the multi-parameter coupled in-situ evaluation of the dry sawing performance of spent fuel assemblies in hot chamber environments. Under conditions of no lubrication and no cooling, circumferential, longitudinal, and cut-off tests are performed on nuclear-grade materials such as the stainless steel cladding, end plugs, and skeleton of irradiated spent fuel assemblies. Simultaneously, full-dimensional signals such as torque, current, vibration, noise, temperature, and high-speed images of the teeth are collected to establish a dry sawing reliability characteristic database, providing high-confidence data support for tool life prediction and failure analysis. The platform features stepless speed regulation of the spindle from 20–6000 rpm and a speed range of 0–1000 rpm. With adjustable feed rate (mm / min), adjustable Z-axis depth of cut, and one-click switching between three cutting modes, the device can quickly map the optimal cutting parameter range. The evaluation results directly guide the development of engineering prototype process packages, shortening the R&D cycle. The device is compatible with various cutting tools such as metal circular saws, ceramic saw teeth, and CBN saw blades, meeting the full-chain performance evaluation needs from basic research to engineering verification. The evaluation method can also be applied to the development of cutting tools for other highly radioactive materials such as fusion reactor cladding and radioactive waste containers, providing common technical support for nuclear facility decommissioning and waste minimization, improving dismantling efficiency and safety, and having significant economic and social benefits.

[0025] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention;

[0027] Figure 2 for Figure 1 The left view;

[0028] Figure 3 for Figure 1 Top view;

[0029] Figure 4 This is a schematic diagram of the working state of a device according to an embodiment of the present invention;

[0030] Figure 5 This is a schematic diagram showing the relative positions of the saw blade and the spent fuel assembly during circumferential cutting according to an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram showing the relative positions of the saw blade and the spent fuel assembly during cutting according to an embodiment of the present invention;

[0032] Figure 7 This is a schematic diagram showing the relative positions of the saw blade and the spent fuel assembly during longitudinal cutting according to an embodiment of the present invention;

[0033] Figure 8 for Figure 7 The left view.

[0034] Among them, the attached figures are labeled

[0035] 1 Main test bench

[0036] 11 Mainframe Rack

[0037] 12 Main Working Platform

[0038] 121 Main T-slot test bench

[0039] 13 Main drive mechanism

[0040] 131 Spindle drive motor

[0041] 132 main shaft reducer

[0042] 133 Spindle Coupling

[0043] 134 Spindle bearing housing

[0044] 14 Lateral drive mechanism

[0045] 141 X-axis drive motor

[0046] 142 X-axis reducer

[0047] 143 X-axis coupling

[0048] 144 X-axis bearing housing

[0049] 145 X-axis lead screw and nut

[0050] 146 X-axis linear guide

[0051] 15 Vertical drive mechanism

[0052] 151 Z-axis support bracket

[0053] 152 Z-axis drive motor

[0054] 153 Z-axis reducer

[0055] 154 Z-axis coupling

[0056] 155 Z-axis bearing housing

[0057] 156 Z-axis lead screw and nut

[0058] 157 Z-axis linear guide

[0059] 16 knives

[0060] 17 Spent fuel assembly clamp

[0061] 2 auxiliary test benches

[0062] 21 Sub-racks

[0063] 22 auxiliary work platforms

[0064] 23 T-slot test benches

[0065] 3 Control System

[0066] 31 Industrial PC

[0067] 32. Pneumatic vortex tube cooler

[0068] 33 dB meter

[0069] 34 Accelerometers

[0070] 35 Temperature sensor

[0071] 36 high-speed cameras

[0072] 4 Spent fuel assembly Detailed Implementation

[0073] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings:

[0074] See Figures 1-3 , Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention. Figure 2 for Figure 1 Left view, Figure 3 for Figure 1A top view. The spent fuel assembly dismantling tool performance evaluation device of the present invention is used for systematic testing and quantitative evaluation of the sawing machinability of nuclear-grade materials such as the stainless steel cladding, end plugs, and skeleton of irradiated spent fuel assemblies 4 under dry, unlubricated conditions. The device includes: a main test bench 1, comprising a main frame 11, a main working platform 12, a main drive mechanism 13, a transverse drive mechanism 14, a vertical drive mechanism 15, a tool 16, and a spent fuel assembly fixture 17. The main working platform 12 is mounted on the main frame 11, and a main T-slot test bench 121 is provided on the main working platform 12; the vertical drive mechanism 15 is mounted on the main working platform 12 via a Z-axis support frame; the transverse drive mechanism 14 is disposed on the main working platform 12 and connected to the main drive mechanism 13; the main drive mechanism 13 is mounted on the Z-axis support frame and connected to the vertical drive mechanism 15; the tool 16 is connected to the main drive mechanism 13; the... The spent fuel assembly fixture 17 is set corresponding to the T-slot test bench; the auxiliary test bench 2 is set on one side of the main frame 11 corresponding to the main drive mechanism 13, including an auxiliary frame 21 and an auxiliary working platform 22 mounted on the auxiliary frame 21, and an auxiliary T-slot test bench 23 is set on the auxiliary working platform 22, which is perpendicular to the T-slot test bench; and the control system 3 is connected to the main drive mechanism 13, the lateral drive mechanism 14 and the vertical drive mechanism 15 respectively, for controlling the main drive mechanism 13, the lateral drive mechanism 14 and the vertical drive mechanism 15, and detecting the torque, current, vibration, noise and cutter 16 temperature output by the main drive mechanism 13 in real time, and monitoring the wear of the cutter 16 teeth and the cutting morphology of the object being cut in real time, collecting and storing test data, and constructing a dry sawing reliability characteristic database, which can realize the cutting test of spent fuel assembly 4 after nuclear irradiation under unlubricated conditions.

[0075] The main drive mechanism 13 in this embodiment includes a rotary spindle, a spindle drive motor 131, and a spindle reducer 132. The spindle reducer 132 is connected to the spindle drive motor 131. The spindle is mounted on a spindle bearing seat 134 and connected to the spindle reducer 132 via a spindle coupling 133. The cutting tool 16 is mounted on the spindle bearing seat 134 via a Morse taper tool holder and is connected to the spindle. The output speed of the spindle drive motor 131 is 20-6000 rpm to accommodate high-speed and low-speed cutting of different types of cutting tools 16.

[0076] The cutting tool 16 in this embodiment can be a metal circular saw, ceramic saw teeth, or CBN saw blade, etc., to systematically test and quantitatively evaluate the machinability of irradiated stainless steel cladding, end plugs, and skeletons for circumferential cutting, longitudinal cutting, and cutting.

[0077] The control system 3 includes an industrial computer 31 and a torque sensor, a current sensor, a decibel meter 33, an acceleration sensor 34, a temperature sensor 35, and a high-speed camera 36, ​​all connected to the industrial computer 31. The torque sensor and current sensor are mounted on the spindle drive motor 131; the acceleration sensor 34, decibel meter 33, and temperature sensor 35 are mounted on the spindle bearing housing 134; and the high-speed camera 36 is positioned corresponding to the cutting tool 16. The control system 3 may also include a pneumatic vortex tube cooler 32, mounted on the Z-axis support frame 151 and connected to the industrial computer 31. The gas pressure of the pneumatic vortex tube cooler 32 is continuously adjustable from 0 to 0.5 MPa, and it cools the cutting tool 16 and accelerates chip removal according to experimental requirements.

[0078] The transverse drive mechanism 14 in this embodiment includes an X-axis drive motor 141, an X-axis reducer 142, an X-axis lead screw and nut 145, and an X-axis linear guide rail 146. The X-axis reducer 142 is connected to the X-axis drive motor 141. The X-axis lead screw and nut 145 is mounted on the main working platform 12 through an X-axis bearing seat 144 and is connected to the X-axis reducer 142 through an X-axis coupling 143. The X-axis linear guide rail 146 is arranged parallel to the X-axis lead screw and nut 145 on the main working platform 12. The vertical drive mechanism 15 includes a Z-axis drive motor 152, a Z-axis reducer 153, a Z-axis lead screw nut 156, and a Z-axis linear guide rail 157. The Z-axis reducer 153 is connected to the Z-axis drive motor 152 and is mounted on the Z-axis support frame 151. The Z-axis lead screw nut 156 is mounted on the Z-axis support frame 151 via a Z-axis bearing seat 155 and is connected to the Z-axis reducer 153 via a Z-axis coupling 154. The Z-axis support frame 151 is connected to the X-axis lead screw nut 145 and moves along the X-axis linear guide rail 146 at a speed of 0-1000 mm / min.

[0079] The main drive mechanism 13 is connected to the Z-axis lead screw nut 156 and moves along the Z-axis linear guide 157 at a speed of 0-200 mm / min. The control system 3 adjusts the main drive mechanism 13 to move forward or backward along the Z-axis to determine the optimal cutting depth of the tool 16, accurately judge the cutting performance of the tool 16, quickly map the optimal cutting parameter range, and switch between three cutting conditions: circumferential cutting, slit cutting, and longitudinal cutting. The three cutting modes can be switched with a single button. The industrial control computer 31 has a "Mode Selection" button on its interactive interface. The PLC program presets motor parameter combinations (speed, feed rate, and travel limit) for the three modes. After clicking the button, the system automatically stops the current operation, switches to the safe initial position of the corresponding mode, loads the preset parameters, and waits for the start command.

[0080] This invention is applicable to the systematic testing and quantitative evaluation of the sawing machinability of nuclear-grade materials such as irradiated stainless steel cladding, end plugs, and skeletons under dry, unlubricated conditions, for the development and performance evaluation of dry cutting tools 16 under different operating conditions (circumferential cutting, longitudinal cutting, and slitting) in spent fuel recovery units. It can perform both circumferential and slitting of spent fuel assemblies 4, as well as longitudinal cutting. For circumferential cutting, spent fuel assembly 4 is placed on the auxiliary test bench 2 with its axis parallel to the saw blade axis; for longitudinal cutting, spent fuel assembly 4 is placed on the main test bench 1 with its axis perpendicular to the saw blade axis. During circumferential and longitudinal cutting, adjusting the Z-axis forward or reverse movement until the cutting depth is greater than the cladding wall thickness achieves disassembly. For slitting, the axis of spent fuel assembly 4 is placed parallel to the saw blade axis, and adjusting the Z-axis forward or reverse movement until the cutting depth is greater than the height of opposite sides of the hexagonal assembly achieves complete slitting of the assembly. Because the main T-slot test bench 121 has a groove in the middle, when circumferentially cutting the spent fuel assembly 4, the spent fuel assembly 4 can be completely cut along the entire cross-section. Due to the groove in the middle of the test bench plate with the T-slot, the dismantling tool 16 will not cut into the test bench plate when completely cutting the spent fuel assembly 4 along the entire cross-section. The groove width B is 20-50mm, preferably 30mm, which is greater than the saw blade thickness (usually 2-5mm) plus a safety clearance; the groove depth H is 10-20mm, preferably 15mm, with a certain safety distance. During cutting, the saw blade enters from one side of the assembly. When cutting below the bottom surface of the assembly, the saw blade teeth enter the hollow area of ​​the groove. The groove design avoids the "cannot be cut" problem caused by traditional solid table surfaces.

[0081] See Figures 4-8 , Figure 4 This is a schematic diagram of the working state of the device according to an embodiment of the present invention. Figure 5 This is a schematic diagram showing the relative positions of the saw blade and spent fuel assembly 4 during circumferential cutting according to an embodiment of the present invention. Figure 6 This is a schematic diagram showing the relative positions of the saw blade and the spent fuel assembly 4 during cutting, according to an embodiment of the present invention. Figure 7 This is a schematic diagram showing the relative positions of the saw blade and spent fuel assembly 4 during longitudinal cutting according to an embodiment of the present invention. Figure 8 for Figure 7 The left view. The method for evaluating the performance of spent fuel assembly dismantling tools according to the present invention, used in the aforementioned spent fuel assembly dismantling tool performance evaluation device, includes the following steps:

[0082] Step S100: Put on the special protective equipment and fix the test tool 16 to the rotating spindle using the corresponding size flange;

[0083] Step S200: Fix the irradiated spent fuel assembly 4 to be cut to the main test bench 1 using the spent fuel assembly clamp 17, ensuring that the material to be cut does not exceed the range of the main test bench 1 or the auxiliary test bench 2; when circumferentially cutting and cutting, the axis of the spent fuel assembly 4 is perpendicular to the rotation surface of the cutting tool 16; when longitudinally cutting, the axis of the spent fuel assembly 4 is parallel to the rotation surface of the cutting tool 16.

[0084] Step S300: The control system 3 sets the corresponding cutting speed (20-6000 rpm) and feed rate (0-1000 mm / min) according to the three working conditions of circumferential cutting, longitudinal cutting, or cut-off; and performs tool setting confirmation, moving the tool 16 to a position where it is just not in contact with the material to be cut; where the moving speed and cutting speed are both feed rates during sawing. For sawing, when the saw blade is fixed, the relationship between feed rate, tooth feed amount, and rotation speed is as follows:

[0085] V f =f n zn;

[0086] Among them, V f f is the feed rate, in mm / min. n is the tooth feed rate, in mm / t; z is the number of saw blade teeth; n is the spindle speed, in rpm;

[0087] Step S400: A pneumatic vortex tube cooler 32 can be added according to the test requirements. The magnetically fixed pneumatic vortex tube cooler 32 can be installed on the Z-axis support frame 151. Its nozzle is adjustable and aligned with the cutting area at a distance of 50-100mm. By connecting to the compressed air pipeline, the gas pressure range is 0-0.5MPa. It can cool the saw blade and accelerate the discharge of sawdust according to the test requirements.

[0088] The pneumatic vortex tube cooler 32 is connected to the control system 3. The solenoid valve control signal is controlled by the PLC digital output module (DO), 24VDC. Pressure monitoring is achieved by a pressure sensor (4-20mA) connected to the AI ​​module for real-time monitoring. When the air source pressure is <0.15MPa, the system automatically reduces the feed speed by 50% and triggers an alarm for safety interlocking. Specific applications are as follows: Manual mode User interface buttons Continuous spray Adjustable from 0.2 to 0.5 MPa Manual control Automatic mode Cutting start signal Turn on when cutting, turn off when stopping. Preset value (default 0.3MPa) Synchronized with cutting Temperature control mode Temperature sensor >250℃ Automatically turns on, turns off when the temperature is below 200°C. 0.4MPa Temperature control

[0089] Step S500: Start the rotation of the cutter 16 and begin the cutting performance evaluation test of the dry cutting of spent fuel assembly 4 by the cutter 16;

[0090] In step S600, during the experiment, the control system 3 automatically collects and records in real time the torque of the spindle drive motor 131, the current of the spindle drive motor 131, and the temperature of the tool 16, and generates and analyzes the time-varying curves of the spindle drive motor 131 torque, the spindle drive motor 131 current, the vibration and noise generated during cutting, and the temperature of the tool 16; and

[0091] Step S700: Combining the saw blade tooth wear and the cut morphology image of the object being cut, evaluate the cutting performance of the saw blade in dry cutting of the spent fuel assembly 4, and construct a dry sawing reliability feature database.

[0092] If, during the test, the torque, current, vibration, noise, and temperature of the spindle drive motor 131 increase sharply and the saw blade suffers severe wear (such as coating peeling, tooth breakage, etc.), it can be determined that the saw blade has reached the end of its service life.

[0093] Step S800: After the test, return the saw blade to its original position after cutting, put on protective equipment and remove the cut irradiated spent fuel assembly 4, clean the test bench surface with compressed air or a vacuum cleaner, and collect and dispose of the relevant waste in accordance with regulations.

[0094] Step S900: Collect some of the saw chips. Further experimental analysis can be conducted on the saw chips, including saw chip morphology analysis, metallographic analysis, XRD diffraction analysis, etc.

[0095] In this embodiment, the spindle drive motor 131 drives the saw blade to rotate via the rotating spindle. The saw blade is fixed to the tool holder by a fastening mechanism, and the tool holder with a Morse taper is mounted on the spindle bearing seat 134. The rotating spindle is connected to the spindle drive motor 131, and its output speed range is 20-6000 rpm, adaptable to different types of saw blades, such as metal circular saws, ceramic saw teeth, and CBN saw blades, for both high-speed and low-speed cutting. The spindle drive motor 131 is equipped with a torque sensor and a current sensor. The spindle bearing seat 134 is equipped with an acceleration sensor 34, a decibel meter 33, and a temperature sensor 35. A high-speed camera 36 is positioned on the ground, facing the saw blade teeth. All sensors are connected to the industrial control computer 31, enabling real-time monitoring of the torque, current, vibration, noise, and saw blade temperature output by the spindle drive motor 131. The high-speed camera 36 monitors the wear of the saw blade teeth and the cutting morphology of the object being cut in real time, facilitating observation and analysis of experimental conditions.

[0096] In this embodiment, the Z-axis support frame 151 is connected to the X-axis lead screw nut 145 and moves along the X-axis via the X-axis linear guide rail 146 at a speed of 0-1000 mm / min. In evaluating the dry cutting performance of a saw blade, changing the moving speed allows for testing and evaluation of the optimal dry cutting speed, accurately determining the saw blade's cutting performance, and quickly mapping the optimal cutting parameter range. The Z-axis drive motor 152 is fixedly connected to the Z-axis lead screw nut 156, driving the spindle drive motor 131 and the rotary spindle to move forward or backward along the Z-axis at an adjustable speed of 0-200 mm / min. By adjusting the forward or reverse Z-axis movement, the optimal depth of cut can be tested and evaluated, accurately determining the saw blade's cutting performance, quickly mapping the optimal cutting parameter range, and switching between circumferential cutting, cut-off, and longitudinal cutting conditions. The Z-axis support frame 151 can be equipped with a pneumatic vortex tube cooler 32 with a gas pressure range of 0-0.5 MPa, which can cool the saw blade and accelerate sawdust discharge according to experimental requirements.

[0097] The optimal cutting parameters were rapidly mapped using a full-factor experiment for initial screening, followed by precise positioning using response surface methodology (RSM). This process is illustrated in the table below. Coarse screening stage Full factorial trial (3 factors, 3 levels) Rotation speed: 500 / 2000 / 4000 rpm; Feed rate: 50 / 300 / 600 mm / min; Depth of cut: 0.5 / 1.5 / 3 mm Precise positioning Central Composite Design (CCD) Refine within ±20% of the optimal range for coarse screening. Evaluation indicators Specific cutting energy (SE), tool wear rate (TWR), and kerf quality (Ra) Weighted composite score

[0098] The full factorial experiment (3 factors, 3 levels) refers to a systematic method that, in the experiment, sets 3 different levels for each of the 3 key process parameters (rotation speed, feed rate, and depth of cut), and exhausts all possible combinations of parameters. This method can comprehensively evaluate the influence of each factor on the processing results and the interactions between them. The parameters in this embodiment are as follows: rotation speed, 500 rpm, 2000 rpm, 4000 rpm; feed rate, 50 mm / min, 300 mm / min, 600 mm / min; depth of cut, 0.5 mm, 1.5 mm, 3 mm. Since it is a 3-factor, 3-level experiment, the total number of experiments is 3³ = 27. This means that cutting tests for these 27 combinations need to be performed sequentially, for example: combination 1, 500 rpm + 50 mm / min + 0.5 mm; combination 2, 500 rpm + 50 mm / min + 1.5 mm; ...; combination 27, 4000 rpm + 600 mm / min + 3 mm. The fast mapping algorithm uses a quadratic regression model to establish the cutting parameters and performance indicators, finding the extreme points by calculating partial derivatives, and determining the optimal parameter range within 15 sets of tests.

[0099] The industrial control computer 31 in this embodiment can control the entire test device and monitor the saw blade speed, the output torque of the spindle drive motor 131, the output current of the spindle drive motor 131, the vibration and noise generated by cutting, and the temperature of the saw blade in real time. The high-speed camera 36 is placed on the ground to monitor the wear of the saw blade and the cutting morphology of the object being cut in real time, which facilitates data recording and test analysis.

[0100] The main spindle drive motor 131 and the Z-axis drive motor 152 are fixed on the Z-axis support frame 151. The spent fuel assembly fixture 17 is fixed on the test bench with a T-slot. The X-axis linear guide rail 146 is fixedly connected to the Z-axis support frame 151. The Z-axis support frame 151 is connected to the X-axis drive motor 141 by a threaded ball screw. The main spindle drive motor 131 drives the saw blade to rotate by rotating the main spindle. The main spindle drive motor 131 is connected to the Z-axis drive motor 152 by a threaded ball screw. The torque sensor, current sensor, acceleration sensor 34, decibel meter 33, high-speed camera 36, ​​and temperature sensor 35 collect data and summarize it in the industrial control computer 31. Under dry conditions without lubrication or cooling, the irradiated spent fuel assembly 4's stainless steel cladding, end plugs, and skeleton, as well as other nuclear-grade materials, are subjected to circumferential cutting, longitudinal cutting, and severing tests. By collecting multi-source data such as cutting torque, current, vibration, noise, temperature, and tooth images in real time, a dry sawing reliability feature database is constructed to quickly map the optimal cutting parameter range.

[0101] Because Taylor's Tool Life Equation for conventional metal cutting is inapplicable due to the lack of work hardening characteristic parameters for nuclear-irradiated materials, this invention employs a multi-sensor fusion criterion for dry sawing characteristics of nuclear-grade materials. The specific implementation of tool life prediction and failure analysis is as follows:

[0102] The predicted tool life for tool 16 is shown in the table below: Wear life High-speed camera captures real-time images of teeth. Image recognition algorithm calculates the flank wear amount VB VB ≥ 0.3mm or coating peeling area > 20% Fatigue life Accelerometer 34 monitors vibration spectrum Identification of tooth crack feature frequencies based on FFT analysis Vibration acceleration > 5g, and the appearance of a characteristic frequency peak. Thermal damage life Temperature sensor 35 monitors the temperature of the saw blade substrate. Temperature-time integral model The substrate temperature is >350℃ and lasts for >30 seconds.

[0103] Failure analysis includes:

[0104] 1) Real-time failure warning: When any two of the torque, current, vibration, noise, and temperature exceed 150% of the average value during the initial stable period, the system will automatically trigger a three-level warning (yellow-orange-red).

[0105] 2) Failure Mode Identification:

[0106] Wear failure: slow increase in torque + stable vibration + slow increase in temperature;

[0107] Tooth breakage failure: sudden increase in vibration / noise + severe torque fluctuation;

[0108] Thermal failure: rapid temperature rise + increased current + material discoloration.

[0109] The detection principles of each sensor are shown in the table below: Torque signal Servo motor encoder + current algorithm Spindle servo drive internal estimation EtherCAT / CanOpen bus Current signal Servo motor power line Spindle servo drive internal acquisition EtherCAT / CanOpen bus Accelerometer top of bearing housing Vibration acceleration Piezoelectric effect → charge signal decibel meter Bearing housing side sound pressure level Capacitor microphone → voltage signal Temperature sensor bearing housing heat source end Infrared radiation / thermoelectric potential Thermocouple → Voltage Signal High-speed camera Ground facing the saw blade Optical images CMOS → Digital Image

[0110] In this system, real-time detection uses a multi-channel data acquisition card (NI PXIe-4499) to connect all sensor signals. The torque and current detection of the spindle drive motor 131 uses the built-in function of the servo system. The torque and current data are uploaded in real time via digital communication. No additional physical sensors are installed on the motor body. The data is collected and processed synchronously through the LabVIEW real-time system.

[0111] The data fusion algorithm aligns six types of data by timestamp to construct a multi-dimensional feature vector. The data acquisition layer includes a servo data bus layer (estimated spindle torque, actual spindle current, actual spindle speed, servo alarm status - EtherCAT) and an external sensor layer (accelerometer 34 (vibration), decibel meter 33 (noise), temperature sensor 35 (temperature), high-speed camera 36 (image) - data acquisition card / network port) – data synchronization layer: unified timestamp (IEEE 1588 precision clock synchronization), data caching and alignment (FIFO queue, 1000ms depth), sampling rate conversion (servo data 1kHz interpolated to 10kHz and aligned with vibration data) — Feature extraction layer: Torque / current: calculation of RMS, peak value, fluctuation coefficient, and spectral features; Vibration: FFT transformation, envelope analysis, and feature frequency extraction; Noise: A-weighted sound pressure level and spectral analysis; Temperature: temperature rise rate and thermal equilibrium time; Image: tooth wear, coating status, and crack identification (AI algorithm) — Evaluation decision layer: Dry sawing performance index (DSPI) calculation, tool life prediction model (LSTM neural network), failure warning and automatic shutdown logic, and dry sawing reliability feature database storage.

[0112] The multi-source data fusion processing in this embodiment includes the following layers: raw data layer (including torque-time, current-time, vibration-time, temperature-time, noise-time, and image sequence) — signal preprocessing layer (including filtering and denoising, anomaly removal, and data alignment) — feature extraction layer (including time domain features, frequency domain features, and image features) — evaluation and decision layer (including wear level, life prediction, and performance rating). The torque / current data processing employs a moving average filter (100ms window width) to eliminate high-frequency noise, calculates the root mean square (RMS) value as a steady-state cutting force index, and calculates the coefficient of variation (CV) as a cutting stability index. Vibration signal processing uses FFT transform to extract spectral features, focusing on the saw tooth passing frequency and its harmonics; a peak at the harmonic indicates tooth damage. Image processing includes: tooth wear detection uses Canny edge detection to extract the tooth profile and compares it with a standard tooth shape to calculate wear; coating peeling identification uses color space conversion (RGB→HSV) to identify the color difference between the coating and the substrate; crack detection uses morphological operations (Top-Hat transform) to enhance crack features; the comprehensive evaluation algorithm establishes a Dry Saw Performance Index (DSPI) and outputs evaluation conclusions based on this: DSPI≥85: Excellent, suitable for engineering applications; 70≤DSPI<85: Good, parameters need optimization; 55≤DSPI<70: Acceptable, only applicable to specific conditions; DSPI<55: Unacceptable, tool or process requires significant improvement.

[0113] Example 1: Circular metal saw (φ300mm, z=60 teeth) used for circumferential cutting of spent fuel assembly cladding. spindle speed 800-2500 rpm 1500 rpm Linear velocity 141-471 m / min, preferably 283 m / min feed rate 50-300 mm / min 150 mm / min The corresponding feed per tooth is 0.017-0.1mm, preferably 0.056mm. Z-axis cutting depth 0.5-3.0 mm 2.0 mm Cut layer by layer, with a single cut depth not exceeding 3mm. Cooling method Non-pneumatic vortex tube cooler Vortex tube 0.3MPa Activate when continuous cutting exceeds 5 minutes

[0114] Example 2: Ceramic serrated (φ250mm, z=40 teeth) longitudinal end plug spindle speed 2000-4000 rpm 3000 rpm Ceramic cutting tools require high-speed cutting, with a linear speed of 314-628 m / min. feed rate 10-80 mm / min 40 mm / min Feed per tooth: 0.008-0.067 mm, preferably 0.033 mm Z-axis cutting depth Layer-by-layer feed 0.5mm / layer Ceramics are brittle, so a shallow depth of cut and multiple passes are used. Cooling method none none Ceramic materials are resistant to high temperatures and can be dry-cut.

[0115] Example 3: CBN saw blade (φ350mm, z=80 teeth) cutting skeleton spindle speed 1500-3500 rpm 2500 rpm CBN's high hardness allows for medium to high rotational speeds, with linear velocities of 165-385 m / min. feed rate 80-500 mm / min 250 mm / min The skeleton material is relatively thick, requiring a large feed rate, 0.021-0.125mm per tooth. Z-axis cutting depth Fixed cutting depth Frame thickness + 2mm Complete cutting is achieved using T-slot grooves. Cooling method pneumatic vortex tube cooler 0.4MPa continuous Cutting large thicknesses generates a lot of heat, so forced cooling is necessary.

[0116] This invention is applicable to the performance evaluation of various cutting tools such as metal circular saws, ceramic saw teeth, and CBN saw blades. It features adjustable cutting speed, feed rate, and cooling method. For dry sawing of nuclear-grade materials, it employs a multi-parameter coupled evaluation method and a feature database. An optional pneumatic vortex tube cooler can be installed to enhance chip removal and cooling effects. This evaluation method can also be applied to special stainless steel materials irradiated with fusion reactor cladding, radioactive waste containers, and other highly radioactive materials. It enables systematic testing and quantitative evaluation of the dry cutting performance of spent fuel assembly dismantling tools, providing data support for material selection, structural optimization, and process parameter formulation of dismantling tools.

[0117] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A performance evaluation device for spent fuel assembly dismantling cutting tools, characterized in that, Systematic testing and quantitative evaluation of the sawing machinability of nuclear-grade materials for irradiated spent fuel assemblies under dry, unlubricated conditions, including: The main test bench includes a main frame, a main working platform, a main drive mechanism, a lateral drive mechanism, a vertical drive mechanism, a cutting tool, and a spent fuel assembly fixture. The main working platform is mounted on the main frame, and a main T-slot test bench is provided on the main working platform. The vertical drive mechanism is mounted on the main working platform via a Z-axis support frame. The lateral drive mechanism is located on the main working platform and connected to the main drive mechanism. The main drive mechanism is mounted on the Z-axis support frame and connected to the vertical drive mechanism. The cutting tool is connected to the main drive mechanism. The spent fuel assembly fixture is provided corresponding to the T-slot test bench. A secondary test bench, located on one side of the main frame corresponding to the main drive mechanism, includes a secondary frame and a secondary working platform mounted on the secondary frame. A secondary T-slot test bench is mounted on the secondary working platform, and the secondary T-slot test bench is perpendicular to the T-slot test bench. The control system is connected to the main drive mechanism, the lateral drive mechanism and the vertical drive mechanism respectively. It is used to control the main drive mechanism, the lateral drive mechanism and the vertical drive mechanism, and to detect the torque, current, vibration, noise and tool temperature output by the main drive mechanism in real time. It also monitors the wear of the tool teeth and the cutting morphology of the object being cut in real time, collects and stores test data, and constructs a dry sawing reliability characteristic database.

2. The spent fuel assembly dismantling tool performance evaluation device as described in claim 1, characterized in that, The main drive mechanism includes a rotary spindle, a spindle drive motor, and a spindle reducer. The spindle reducer is connected to the spindle drive motor. The spindle is mounted on a spindle bearing housing and connected to the spindle reducer via a spindle coupling. The cutting tool is mounted on the spindle bearing housing via a Morse taper tool holder and is connected to the spindle.

3. The spent fuel assembly dismantling tool performance evaluation device as described in claim 2, characterized in that, The output speed of the spindle drive motor is 20-6000 rpm to adapt to high-speed and low-speed cutting of different types of tools.

4. The spent fuel assembly dismantling tool performance evaluation device as described in claim 3, characterized in that, The cutting tools are metal circular saws, ceramic saw teeth, or CBN saw blades. The machinability of irradiated stainless steel cladding, end plugs, and skeletons for circumferential cutting, longitudinal cutting, and cut-off is systematically tested and quantitatively evaluated.

5. The spent fuel assembly dismantling tool performance evaluation device as described in claim 2, characterized in that, The control system includes an industrial computer and a torque sensor, a current sensor, a decibel meter, an acceleration sensor, a temperature sensor, and a high-speed camera, all connected to the industrial computer. The torque sensor and the current sensor are mounted on the spindle drive motor; the acceleration sensor, the decibel meter, and the temperature sensor are mounted on the spindle bearing housing; and the high-speed camera is positioned corresponding to the cutting tool.

6. The spent fuel assembly dismantling tool performance evaluation device as described in claim 5, characterized in that, The control system also includes a pneumatic vortex tube cooler, which is installed on the Z-axis support and connected to the industrial computer. The gas pressure of the pneumatic vortex tube cooler is continuously adjustable from 0 to 0.5 MPa. It cools the tool and accelerates chip removal according to the test requirements.

7. The spent fuel assembly dismantling tool performance evaluation device as described in claim 1, characterized in that, The transverse drive mechanism includes an X-axis drive motor, an X-axis reducer, an X-axis lead screw and nut, and an X-axis linear guide. The X-axis reducer is connected to the X-axis drive motor. The X-axis lead screw and nut are mounted on the main working platform through an X-axis bearing seat and are connected to the X-axis reducer through an X-axis coupling. The X-axis linear guide is arranged parallel to the X-axis lead screw and nut on the main working platform and is connected to the Z-axis support frame.

8. The spent fuel assembly dismantling tool performance evaluation device as described in claim 7, characterized in that, The vertical drive mechanism includes a Z-axis drive motor, a Z-axis reducer, a Z-axis lead screw and nut, and a Z-axis linear guide. The Z-axis reducer is connected to the Z-axis drive motor and is mounted on the Z-axis support frame. The Z-axis lead screw and nut are mounted on the Z-axis support frame via a Z-axis bearing seat and are connected to the Z-axis reducer via a Z-axis coupling. The Z-axis support frame is connected to the X-axis lead screw and nut and moves along the X-axis linear guide at a speed of 0-1000 mm / min.

9. The spent fuel assembly dismantling tool performance evaluation device as described in claim 8, characterized in that, The main drive mechanism is connected to the Z-axis lead screw and moves along the Z-axis linear guide at a speed of 0-200 mm / min. The control system adjusts the main drive mechanism to move forward or backward along the Z-axis to determine the optimal cutting depth of the tool, accurately judge the cutting performance of the tool, quickly map the optimal cutting parameter range, and switch between circumferential cutting, slitting, or longitudinal cutting conditions.

10. A method for evaluating the performance of a spent fuel assembly dismantling tool, characterized in that, The spent fuel assembly dismantling tool performance evaluation device according to any one of claims 1-9 includes the following steps: Fix the tool to be tested to the rotating spindle; The spent fuel assembly to be cut is fixed to the main test bench using a spent fuel assembly clamp; during circumferential cutting and slit cutting, the axis of the spent fuel assembly is perpendicular to the rotation plane of the cutting tool; during longitudinal cutting, the axis of the spent fuel assembly is parallel to the rotation plane of the cutting tool. The control system sets the corresponding cutting speed and feed rate according to the circumferential cutting, longitudinal cutting, or slit cutting conditions; and performs tool setting confirmation, moving the tool to a position where it is just out of contact with the material to be cut; Start the blade rotation to begin the cutting performance evaluation test of the blade dry cutting the spent fuel assembly; During the experiment, the control system automatically collected and recorded the spindle drive motor torque, spindle drive motor current and tool temperature in real time, and generated curves showing the changes of spindle drive motor torque, spindle drive motor current, vibration and noise generated during cutting and tool temperature over time. By combining images of saw blade tooth wear and cut morphology of the object being cut, the cutting performance of dry sawing of spent fuel assemblies is evaluated, and a database of dry sawing reliability characteristics is constructed. as well as Establish a dry sawing performance index and output evaluation conclusions based on the dry sawing performance index.

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