A core positioning method for a nuclear reactor loader and unloader

Abstract

The present invention relates to the technical field of commissioning of a loader and unloader of a pressurized water reactor nuclear power plant, and specifically discloses a method for core positioning of a loader and unloader of a nuclear reactor. The method comprises the following steps: Step 1: Initializing the core coordinates of the loader and unloader. Step 2: Confirming and adjusting the skew state of the loader and unloader carriages. Step 3: Measuring and adjusting the verticality of the fixed sleeve, telescopic sleeve, fuel assembly model 1, and core enclosure; Step 4: Measuring and adjusting the horizontality of the loader and unloader hook and the core lower plate components; Step 5: Encoder adjustment; Step 6: Core positioning. The method calculates and sets the coordinates of the loader and unloader assembly core positioning through the fuel assembly model, thereby improving the core positioning accuracy, avoiding collision between the assembly and the enclosure, and significantly improving the efficiency of the core positioning operation.

Description

Technical Field

[0001] The invention belongs to the technical field of commissioning of a loader and unloader of a pressurized water reactor nuclear power plant, and in particular relates to a core positioning method of a loader and unloader of a nuclear reactor. Background Art

[0002] The Hualong One is a million-kilowatt, third-generation pressurized water reactor (PWR) nuclear power unit independently designed and built in my country. Its reactor core utilizes a layout of 177 advanced nuclear fuel assemblies. Core positioning for PWR loading and unloading equipment (referred to as "core positioning") is a critical task that occupies a significant portion of the plant's main line of work during the construction, installation, and commissioning phases. Core positioning is fundamental to fuel assembly loading and unloading at a nuclear power plant, and its accuracy, efficiency, and maintenance costs directly impact the safety and profitability of loading and unloading. From the perspective of core positioning alone, the ideal approach is to calibrate and store the coordinates of each core assembly during equipment commissioning. However, this approach is extremely labor-intensive and consumes significant time. Furthermore, the distribution of core assemblies is highly regular, making it a generally unsuitable method for core positioning. Traditional single-point and four-point positioning methods also fall short in terms of accuracy, efficiency, and maintenance costs.

[0003] Core positioning is a complex systemic task, influenced by many factors. First, maximizing positioning accuracy is a core consideration in core positioning. Second, the vast majority of core positioning work occurs during the installation and commissioning phase of a nuclear power plant, making the efficiency of core positioning a key concern. Furthermore, prior to each refueling overhaul, the loading and unloading machine requires comprehensive maintenance, and the efficiency and cost of core positioning maintenance are also key considerations. Therefore, core positioning primarily addresses three key aspects: positioning accuracy, operational efficiency, and maintenance costs, to ensure the safety and effectiveness of nuclear power plant loading and unloading operations. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for positioning the core of a nuclear reactor loader and unloader in view of the above-mentioned deficiencies in the prior art.

[0005] In order to solve the above problems, the technical solution of the present invention is as follows: a method for positioning the core of a nuclear reactor loader and unloader, the method comprising the following steps:

[0006] Step 1: Initialize the core coordinates of the loader. The loader grabs the fuel assembly model and transports it to any fuel assembly position near the coaming of the core. The core coordinates are initialized in the loader core coordinate program.

[0007] Step 2: Confirm and adjust the skew status of the trolley and carriage of the loader and unloader. Move the loader and unloader to the H08 position of the core, and confirm and adjust the skew status of the trolley and carriage;

[0008] Step 3: Measure and adjust the verticality of the fixed sleeve, telescopic sleeve, fuel assembly model 1, and core shroud;

[0009] Step 4: Measure and adjust the levelness of the loader hook and the lower core plate components;

[0010] Step 5: Encoder calibration. Measure and adjust the deviation between the tooth pitch at the joints and the tooth pitch at the non-joints of the racks on the loader and trolley tracks that match the encoder travel gears, and the deviation between the actual movement distance of the loader and trolley within the core range and the distance displayed by the encoder.

[0011] Step 6: Core positioning. The fuel assembly model is transferred to the H08, M02, P04, P12, M14, D14, B12, B04, and D02 positions by the loader and unloader, and the coordinates are recorded. The coordinate values ​​displayed by the loader and unloader positioning system are reset using the coordinate values ​​of the H08 position. The step lengths of adjacent fuel assemblies and the coordinate positions of all positions in the core are calculated using the coordinate values ​​of the H08, M02, P04, P12, M14, D14, B12, B04, and D02 positions.

[0012] The deflection states of the trolley and the small car in step 2 include the deflection of the trolley in the Y direction and the core axis, the deflection of the small car in the X direction and the core axis, and the deflection of the trolley and the small car body.

[0013] The step 2 further comprises the following steps:

[0014] S201: Confirm the deflection of the trolley in the Y direction relative to the core axis and make corrections to the trolley; confirm the deflection of the trolley in the X direction relative to the core axis and make corrections to the trolley;

[0015] S202: Use the theodolite to measure the deflection of the trolley and the car body and record it. At the same time, record the position and deviation value displayed by the master and slave encoders of the trolley and the car, and make temporary marking points at the H08 position of the loader and unloader trolley;

[0016] S203: The loader and unloader move to the tipping machine position and are accurately aligned with the tipping machine position. The deflection of the trolley and car body is measured with a theodolite and recorded. At the same time, the positions and deviation values ​​displayed by the master and slave encoders of the loader and unloader trolley and car are recorded, and temporary marking points are made for the trolley and car body at the tipping machine position.

[0017] The adjacent fuel assembly step lengths in step 6 include the adjacent assembly step lengths in the X direction and the adjacent assembly step lengths in the Y direction.

[0018] The method further includes step 7: verifying the core positioning effect. A position whose position boundary includes the core panel is selected for verification to observe whether the fuel assembly model collides with the core panel when it falls into the position.

[0019] The method also includes step 8: measuring the core positioning margin. The core positioning margin is measured at the center of each quadrant of the core. The fuel assembly model is transported to the L05 coordinate position by a loading and unloading machine, and the fuel assembly model is lowered. When the lower tube seat of the fuel assembly model is 50 mm away from the lower core plate, the loading and unloading machine is activated in bypass mode and moves in the directions of 0°, 90°, 180°, and 270° respectively until the loading and unloading machine generates an underload alarm in the directions of 0°, 90°, 180°, and 270°. The offset values ​​in the directions of 0°, 90°, 180°, and 270° are recorded, and the minimum of the offset values ​​in the directions of 0°, 90°, 180°, and 270° is taken as the core positioning margin.

[0020] The method further includes step 9: marking a permanent reference point for core positioning, setting the H08 position and the tipping machine position as permanent reference points.

[0021] The step 9 further comprises the following steps:

[0022] S901: Move the loader to position H08, compare and adjust it with the temporary mark made in step S202, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicles, and mark H08 as the permanent reference point;

[0023] S902: Move the loader to the tipping machine position, compare and adjust it with the temporary mark made in step S203, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicle owners, and mark the tipping machine position as a permanent reference point.

[0024] The loader and unloader grabs the fuel assembly model and transports it to position A06.

[0025] The significant effect of the present invention is that: the method for core positioning of a nuclear reactor loader and unloader described in the present invention calculates and sets the coordinates of the component core positioning of the loader and unloader through a fuel assembly model, thereby improving the core positioning accuracy, avoiding collision between the assembly and the enclosure, and significantly improving the efficiency of the core positioning operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural schematic diagram of an auxiliary device used in a core positioning method for a nuclear reactor loader and unloader according to the present invention;

[0027] Figure 2This is a schematic diagram of the core coordinate quadrant layout of a core positioning method for a nuclear reactor loader and unloader according to the present invention;

[0028] Figure 3 This is a flow chart of a method for positioning the core of a nuclear reactor loader and unloader according to the present invention;

[0029] In the figure: 1. Dummy fuel assembly; 2. Lower core plate; 3. Measuring device; 4. Positioning pin. DETAILED DESCRIPTION

[0030] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of the present invention.

[0031] In the description of the present invention, it should be noted that the directions or positional relationships indicated by “upper” and the like are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as a limitation on the present invention.

[0032] In the description of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connect," "dispose," "install," "fix," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may refer to direct connection, indirect connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0034] like Figure 1 As shown, a core positioning method for a nuclear reactor loader and unloader according to the present invention uses the following mold as an auxiliary device for the positioning method, comprising a fuel assembly model 1, a core lower plate 2, a measuring device 3, and positioning pins 4; the core lower plate 2 is a grid-like structure in which the grids have the same size; positioning pins 4 are provided at the intersections of the grids of the core lower plate 2, and two positioning pins 4 are provided at each intersection of the core lower plate 2, except for the intersections at the outer edge of the core lower plate 2; measuring devices 3 are provided on the four sides of the grid where the fuel assembly model 1 falls, serving as a distance reference for the fuel assembly model 1; and a surrounding plate is provided at the edge of the core;

[0035] like Figure 2As shown in the figure, a method for positioning the core of a nuclear reactor loader and unloader according to the present invention uses this figure as a schematic diagram of the core coordinate quadrant arrangement of the core cavity formed by the core shroud; the directions of 0°, 90°, 180°, and 270° are schematically marked in the figure;

[0036] The present invention provides a method for positioning the core of a nuclear reactor loader and unloader, the method comprising the following steps:

[0037] Step 1: Initialize the core coordinates of the loader. The loader grabs the fuel assembly model 1 and transports it to any fuel assembly position near the coaming of the core. The core coordinates are initialized in the loader core coordinate program.

[0038] As an embodiment, the loader grabs the fuel assembly model 1 and transports it to Figure 2 A06 position in;

[0039] Step 2: Confirm and adjust the skew status of the loader and unloader trolleys. When the loader and unloader moves to the core H08 position, confirm and adjust the skew status of the loader and unloader trolleys to ensure that their postures meet the requirements for normal operation of the loader and unloader. The skew status includes the skew of the trolley in the Y direction and the core axis, the skew of the trolley in the X direction and the core axis, and the skew of the trolley and the trolley body.

[0040] S201: Confirm and record the deviation of the trolley in the Y direction relative to the core axis. In one embodiment, the trolley is corrected mechanically. In another embodiment, the trolley is corrected using the encoder correction function of the loader to ensure that the deviation of the trolley in the Y direction relative to the core axis meets the design requirements.

[0041] Confirm and record the deviation of the trolley in the X direction relative to the core axis. In one embodiment, the trolley is corrected mechanically. In another embodiment, the trolley is corrected using the encoder correction function of the loader to ensure that the deviation of the trolley in the X direction relative to the core axis meets the design requirements.

[0042] S202: Use the theodolite to measure the deflection of the trolley and the car body and record it. At the same time, record the position and deviation value displayed by the master and slave encoders of the trolley and the car, and make temporary marking points at the H08 position of the loader and unloader trolley;

[0043] S203: The loader and unloader move to the tipping machine position and are accurately aligned with the tipping machine position. The deflection of the trolley and car body is measured with a theodolite and recorded. At the same time, the positions and deviation values ​​displayed by the master and slave encoders of the loader and unloader trolley and car are recorded, and temporary marking points are made for the trolley and car body at the tipping machine position.

[0044] Step 3: Measure, record, and adjust the verticality of the fixed sleeve, telescopic sleeve, fuel assembly model 1, and core shroud to ensure they meet normal operating requirements.

[0045] Step 4: Measure, record, and adjust the levelness of the loader hook and the lower core plate components to meet normal working requirements;

[0046] Step 5: Encoder calibration. Measure and adjust the deviation between the tooth pitch at the joints and the tooth pitch at the non-joints of the racks on the loader and trolley tracks that mate with the encoder travel gears, and the deviation between the actual travel distance of the loader and trolley within the core range and the distance displayed by the encoder.

[0047] Step 6: Core positioning.

[0048] S601: Measure the coordinate value of position H08. The fuel assembly model 1 is transferred to the upper part of position H08 by the loading and unloading machine. The fuel assembly model 1 is lowered and stopped at a distance of 2 to 50 mm from the lower core plate. Four measuring devices 3 are installed on the positioning pins 4 at the four positions adjacent to position H08. The positions of the loading and unloading machine trolley and the trolley are adjusted so that the distance from the four surfaces of the lower tube seat of the fuel assembly model 1 to the measuring devices 3 is 1 mm. The coordinate value of H08 at this time (X H08 , Y H08 ), and reset the displayed coordinate value of the loader positioning system according to this coordinate value;

[0049] S602: Repeat step S601 to measure the coordinate values ​​of eight points (X, M02 , Y M02 )、(X P04 , Y P04 )、(X P12 , Y P12 )、(X M14 , Y M14 )、(X D14 , Y D14 )、(X B12 , Y B12 )、(X B04 , Y B04 ) and (X D02 , Y D02 ). (The difference between S602 and S601 is only the location of measurement).

[0050] S603: X-direction adjacent component step length, Y-direction adjacent component step length, X-direction coordinate calculation formula, Y-direction coordinate calculation formula

[0051]

[0052] Where: m is the coordinate position to be measured, the number of steps from the H08 position in the X-axis direction;

[0053] n is the coordinate position to be measured, the number of steps from the H08 position in the Y-axis direction;

[0054] The coordinates of each position in the core are calculated using the above formula and stored in the coordinate database of the loader positioning system;

[0055] Step 7: Verify the core positioning. Select a location within the core enclosure for verification. Observe whether the fuel assembly model 1 collides with the core enclosure when it is placed in that location. As an example, eight locations, K01, R06, R10, K15, F15, A10, A06, and F01, are selected for verification. If there is any collision, measure and adjust that location. Once verification is successful, adjust and solidify the coordinate database.

[0056] Step 8: Core positioning margin measurement. Specifically, the core positioning margin is measured at the center position of each quadrant of the core (as an embodiment, the center position of each quadrant is L05, L11, E11 and E05 respectively); as an embodiment, the margin at the L05 position is measured, the fuel assembly model 1 is transported to the L05 coordinate position by the loader and unloader, the fuel assembly model 1 is lowered, and when the lower tube seat of the fuel assembly model 1 stops at a distance of 2 to 50 mm from the lower plate of the core, the loader and unloader bypass is started, and the loader and unloader carts are horizontally displaced in the directions of 0°, 90°, 180°, and 270° respectively, and the loader and unloader telescopic sleeve is vertically lifted and lowered until the loader and unloader respectively generate underload alarms in the directions of 0°, 90°, 180°, and 270°, and the offset values ​​in the directions of 0°, 90°, 180°, and 270° are recorded respectively, and the minimum value among the offset values ​​in the directions of 0°, 90°, 180°, and 270° is taken as the core positioning margin;

[0057] Step 9: Mark the permanent reference points for core positioning. According to the coordinate database, adjust the scale plates of the loader and unloader to meet the design requirements, and set the H08 position and the tipping machine position as permanent reference points.

[0058] S901: Move the loader to position H08, compare and adjust it with the temporary mark made in step S202, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicles, and mark H08 as the permanent reference point;

[0059] S902: Move the loader to the tipping machine position, compare and adjust it with the temporary mark made in step S203, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicles, and mark the tipping machine position as a permanent reference point;

[0060] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A method for positioning the core of a nuclear reactor loader and unloader, characterized by: The method comprises the following steps: Step 1: Initialization of the core coordinates of the loader and unloader; the loader and unloader grabs the fuel assembly model (1), transports it to any fuel assembly position near the coaming of the core, and initializes the core coordinates in the loader and unloader core coordinate program; Step 2: Confirm and adjust the skew status of the trolley and carriage of the loader and unloader; move the loader and unloader to the H08 position of the core, and confirm and adjust the skew status of the trolley and carriage; Step 3: Measure and adjust the verticality of the fixed sleeve, telescopic sleeve, fuel assembly model (1), and core shroud; Step 4: Measure and adjust the levelness of the loader hook and the lower core plate components; Step 5: Encoder calibration: Measure and adjust the deviation between the tooth pitch at the joint and the tooth pitch at the non-joint of the racks on the loader and unloader trolley tracks that match the encoder travel gears, and the deviation between the actual movement distance of the loader and unloader trolley within the core range and the distance displayed by the encoder. Step 6: Core positioning: The fuel assembly model (1) is transferred to the positions H08, M02, P04, P12, M14, D14, B12, B04 and D02 respectively by the loader and unloader, and the coordinates are recorded. The displayed coordinate values ​​of the positioning system of the loader and unloader are reset with the coordinate values ​​of the H08 position. The step lengths of adjacent fuel assemblies and the coordinate positions of all the positions in the core are calculated with the coordinate values ​​of the H08, M02, P04, P12, M14, D14, B12, B04 and D02 positions. The method further comprises step 7: verifying the core positioning effect; selecting a position whose position boundary includes the shroud for verification, and observing whether the fuel assembly model (1) collides with the core shroud when it falls into the position; The method further comprises step 8: measuring the core positioning margin; measuring the core positioning margin at the center position of each quadrant of the core, transporting the fuel assembly model (1) to the L05 coordinate position by a loading and unloading machine, lowering the fuel assembly model (1), stopping when the lower tube seat of the fuel assembly model (1) is 50 mm away from the lower plate (2) of the core, starting the loading and unloading machine bypass, and performing displacement operations in the directions of 0°, 90°, 180°, and 270° respectively, until the loading and unloading machine respectively generates an underload alarm in the directions of 0°, 90°, 180°, and 270°, and recording the offset values ​​in the directions of 0°, 90°, 180°, and 270° respectively, and taking the minimum value among the offset values ​​in the directions of 0°, 90°, 180°, and 270° as the core positioning margin; The method further comprises step 9: marking a permanent reference point for positioning the core; setting the H08 position and the tipping machine position as permanent reference points; The step 9 further comprises the following steps: S901: Move the loader to position H08, compare and adjust it with the temporary mark made in step S202, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicles, and mark H08 as the permanent reference point; S902: Move the loader to the tipping machine position, compare and adjust it with the temporary mark made in step S203, and make a permanent mark. At the same time, record the position and deviation value displayed by the encoder of the large and small vehicle owners, and mark the tipping machine position as a permanent reference point.

2. A method for positioning a core of a nuclear reactor loader and unloader according to claim 1, characterized in that: The deflection states of the trolley and the small car in step 2 include the deflection of the trolley in the Y direction and the core axis, the deflection of the small car in the X direction and the core axis, and the deflection of the trolley and the small car body.

3. A method for positioning a core of a nuclear reactor loader and unloader according to claim 1, characterized in that: The step 2 further comprises the following steps: S201: Confirm the deflection of the trolley in the Y direction relative to the core axis and make corrections to the trolley; confirm the deflection of the trolley in the X direction relative to the core axis and make corrections to the trolley; S202: Use the theodolite to measure the deflection of the trolley and the car body and record it. At the same time, record the position and deviation value displayed by the master and slave encoders of the trolley and the car, and make temporary marking points at the H08 position of the loader and unloader trolley; S203: The loader and unloader move to the tipping machine position and are accurately aligned with the tipping machine position. The deflection of the trolley and car body is measured with a theodolite and recorded. At the same time, the positions and deviation values ​​displayed by the master and slave encoders of the loader and unloader trolley and car are recorded, and temporary marking points are made for the trolley and car body at the tipping machine position.

4. A method for positioning a core of a nuclear reactor loader and unloader according to claim 1, characterized in that: The adjacent fuel assembly step lengths in step 6 include the adjacent assembly step lengths in the X direction and the adjacent assembly step lengths in the Y direction.

5. The method for core positioning of a nuclear reactor loader and unloader according to claim 1, characterized in that: The loader grabs the fuel assembly model (1) and transports it to position A06.

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