Method for correcting and calculating outline of fuel assembly and method for judging influence on charging

Abstract

The invention relates to the field of fuel assemblies, in particular to a correction calculation method for the outline of a fuel assembly and a judgment method for influence on charging. The correction calculation method comprises the following steps: firstly, collecting data of two surfaces of an undeformed standard fuel assembly and a fuel assembly to be detected, wherein the data comprises distances between an upper tube seat, a lower tube seat and a positioning grid and a probe; calculating the reading offset of each layer of positioning grillwork; comparing the reading offset of each layer of the positioning grillwork and the reading offset of the upper tube seat, and calculating the deformation of each layer of the positioning grillwork; selecting two adjacent layers of grillwork, connecting the two layers of grillwork into a straight line, and calculating the middle offset of each layer of positioning grillwork under the condition of no deformation by taking the offset of the two grillwork as a reference; calculating the correction deformation of each layer of positioning grillwork of the fuel assembly by using the reading offset and the middle offset to obtain the maximum correction deformation of the fuel assembly; and calculating the correction deformation of the lower tube seat relative to the upper tube seat. According to the invention, the accuracy of fuel assembly contour calculation is improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel assemblies, and in particular to a method for correcting the calculation of the outer contour of a fuel assembly and a method for determining the influence on fuel loading. Background Art

[0002] After irradiation, the outer contour of the fuel assembly changes relative to the standard fuel assembly, and phenomena such as fuel assembly bending occur, that is, the centers of the upper and lower nozzle seats of the fuel assembly deviate, which may lead to difficulties in positioning the fuel assembly and the lower nozzle seat cannot be accurately positioned; it may also increase the risk of scratching during the movement of the fuel assembly.

[0003] At present, nuclear power plants generally measure the positional relationship between the nozzle seat and each layer of positioning grids through technologies such as ultrasonic or laser, and calculate the outer contour of the fuel assembly through the positional relationship. This calculation method does not consider the influence of the measurement environment, that is, the fuel assembly may shake or the assembly itself may be in an inclined state during the measurement, and the measured relative positional relationship may be inaccurate, resulting in too large an error in the measurement of the outer contour of the fuel assembly.

[0004] If the measurement and calculation of the outer contour of the fuel assembly are inaccurate, it will provide incorrect guidance for fuel operation, leading to the adoption of incorrect fuel operation strategies, and at this time, the risk of fuel operation will be greatly increased. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for correcting the calculation of the outer contour of a fuel assembly and a method for determining the influence on fuel loading, eliminating the influence of fuel assembly shaking and assembly inclination, and improving the accuracy of calculating the outer contour of the fuel assembly.

[0006] The present invention provides a method for correcting the calculation of the outer contour of a fuel assembly, including the following steps:

[0007] Step S1: Use the fuel assembly outer contour measuring device to first collect the distances between the upper nozzle seat, the lower nozzle seat, and the positioning grid and the probe on one surface of the undeformed standard fuel assembly, and then rotate 90 degrees to collect the distances between the upper nozzle seat, the lower nozzle seat, and the grid and the probe on another surface;

[0008] Step S2: Then collect the data of the same two surfaces of the fuel assembly to be measured. First, collect the distances between the upper nozzle seat, the lower nozzle seat, and the grid and the probe on one surface, and then rotate 90 degrees to collect the distances between the upper nozzle seat, the lower nozzle seat, and the grid and the probe on another surface;

[0009] Step S3: Calculate the reading offset of each layer of positioning grid;

[0010] Step S4: Compare the reading offset of each layer of positioning grid with that of the upper nozzle seat, and calculate the deformation amount of each layer of positioning grid;

[0011] Step S5: Select two adjacent layers of grids, connect the two layers of grids into a straight line, and calculate the intermediate offset of each layer of positioning grids without deformation based on the offset between the two grids, considering the vertical position relationship of each layer of positioning grids of the fuel assembly in the design.

[0012] Step S6: Calculate the corrected deformation amount of each layer of positioning grids of the fuel assembly by using the reading offset and the intermediate offset, and obtain the maximum corrected deformation amount of the fuel assembly.

[0013] Step S7: Calculate the corrected deformation amount of the lower nozzle relative to the upper nozzle.

[0014] In a specific embodiment of the present invention, in step S3, the reading offset of the selected positioning grid is the distance between the component to be measured and the probe minus the distance between the standard component and the probe.

[0015] In a specific embodiment of the present invention, in step S4, the deformation amount of each layer of positioning grid is the reading offset of this layer of positioning grid minus the reading offset of the upper nozzle.

[0016] In a specific embodiment of the present invention, in step S5, select the first layer of grid and the second layer of grid, and connect the first layer of grid and the second layer of grid into a straight line.

[0017] In a specific embodiment of the present invention, in step S5,

[0018] The intermediate offset of the upper nozzle Δ′1 = Δ1 - d1*(Δ3 - Δ2) / d2;

[0019] The intermediate offset of the first layer of grid Δ′2 = Δ2;

[0020] The intermediate offset of the second layer of grid Δ′3 = Δ3;

[0021] The intermediate offset of the Nth layer of grid Δ′ (N+1) =(d2 +... + d N )*(Δ3 - Δ2) / d2 + Δ2;

[0022] The intermediate offset of the lower nozzle Δ′ (N+2) =(d2 +... + d N+1 )*(Δ3 - Δ2) / d2 + Δ2;

[0023] where, Δ' is the intermediate offset; d1 is the vertical distance from the upper nozzle to the first layer of grid, d2 is the vertical distance from the first layer of grid to the second layer of grid... d N+1 is the vertical distance between the N - 1th layer of grid and the Nth layer of grid, d N+2 is the vertical distance from the Nth layer of grid to the lower nozzle;

[0024] The reading offset of the upper nozzle is Δ1, the reading offset of the first grid is Δ2, ……, Δ (N+1) is the reading offset of the Nth grid, and Δ (N+2) is the reading offset of the lower nozzle, where N is a natural number.

[0025] In a specific embodiment of the present invention, in the step S6, the corrected deformation amount is the reading offset minus the intermediate offset.

[0026] In a specific embodiment of the present invention, in the step S6, the maximum corrected deformation amount of the fuel assembly is B max ;

[0027] B max = max(|upper nozzle deformation amount|, |Nth grid deformation amount|, …, |lower nozzle deformation amount|)(4);

[0028] In formula 4, N is a natural number.

[0029] In a specific embodiment of the present invention, in the step S7, the corrected deformation amount of the lower nozzle relative to the upper nozzle is the corrected deformation amount of the lower nozzle minus the corrected deformation amount of the upper nozzle.

[0030] In a specific embodiment of the present invention, in the step S1, the fuel assembly outer contour measurement device uses a laser probe, and each of the upper nozzle, the lower nozzle, and each grid corresponds to a probe, and the probe is arranged parallel to the grid.

[0031] The present invention provides a method for determining the influence of the deformation of the fuel assembly outer contour on loading, including the following steps:

[0032] Step S1: Calculate the corrected deformation amount using the method;

[0033] Step S2: Determine the calculated corrected deformation amount.

[0034] If the following two conditions are simultaneously satisfied, there will be difficulties in the core placement operation of the fuel assembly, and it is necessary to consider the fuel assembly loading operation plan in advance to help the fuel assembly with a large deformation to be successfully placed;

[0035] Condition 1: The corrected deformation amount of the lower nozzle of the fuel assembly relative to the upper nozzle is greater than the radius of the positioning hole of the lower nozzle;

[0036] Condition 2: The lower nozzle of the fuel assembly is deflected relative to the upper nozzle in the R direction, and when the core is placed, the R direction is an open position.

[0037] Compared with the prior art, the method for correcting the calculation of the outer contour of the fuel assembly of the present invention fully considers the factors affecting the measurement of the outer contour of the fuel assembly, including fuel assembly sloshing, assembly tilting, etc., can eliminate the influence of the above factors, and can accurately calculate the outer contour of the fuel assembly. The method for determining the influence of the deformation of the outer contour of the fuel assembly on loading can identify the operation risks of the fuel assembly in the core of the nuclear power plant in advance. For the fuel assemblies identified as having difficulties in being in place, the fuel assembly operation plan can be considered in advance to help the fuel assemblies with larger deformations to be in place smoothly, reduce the risks of fuel operation, and improve the efficiency of fuel operation. Brief Description of the Drawings

[0038] Figure 1 It shows a schematic structural diagram of a device for measuring the outer contour of a fuel assembly;

[0039] In the figure, 1 - fixed base, 2 - clamping rod, 3 - probe, 4 - upper tube seat, 5 - positioning grid, 6 - lower tube seat. Detailed Embodiment

[0040] To further understand the present invention, the implementation schemes of the present invention will be described below in conjunction with embodiments. However, it should be understood that these descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the present invention.

[0041] An embodiment of the present invention discloses a method for correcting the calculation of the outer contour of a fuel assembly, including the following steps:

[0042] Step S1: Use the device for measuring the outer contour of the fuel assembly to first collect the distances between the upper tube seat, the lower tube seat, and the positioning grid and the probe on one surface of the undeformed standard fuel assembly, and then rotate 90 degrees to collect the distances between the upper tube seat, the lower tube seat, and the grid and the probe on another surface;

[0043] As Figure 1 shown, the structure of the device for measuring the outer contour of the fuel assembly is:

[0044] The fixed base 1 is detachably installed at the measurement station, the clamping rod 2 is installed on the fixed base 1, the clamping rod 2 is used to install and support the probe 3, there are multiple probes 3, and the multiple probes 3 are installed on the outer circumferential surface of the clamping rod 2 at intervals along the axial direction of the clamping rod 2, and moreover, the multiple probes 3 correspond to multiple parts to be measured on the fuel assembly one by one.

[0045] The fuel assembly usually includes a positioning skeleton and fuel rods placed in the skeleton. The skeleton includes an upper tube seat 4, a lower tube seat 6, and several positioning grids 5 provided between the upper tube seat 4 and the lower tube seat 6. Different types of fuel assemblies have different numbers of positioning grids 5. For example, the AP1000 fuel assembly has eight positioning grids 5.

[0046] When measuring in the present invention, it is necessary to simultaneously obtain the position information of the upper nozzle 4, the lower nozzle 6 and each positioning grid 5 of the fuel assembly. Therefore, the upper nozzle 4, the lower nozzle 6 and each positioning grid 5 are multiple parts to be measured on the fuel assembly to be measured. The number of the probes 3 matches the number of the parts to be measured on the fuel assembly. Therefore, the number of the probes 3 is not limited and can be set according to the type of the fuel assembly, specifically according to the number of the positioning grids 5 of the fuel assembly. Each probe 3 includes a laser generator and an image collector. The laser generator is used to project laser onto the surface to be measured of the corresponding part to be measured on the fuel assembly. The form of the laser projected by the laser generator is not limited and can be line laser, point laser or structured light. The image collector is used to collect the image of the surface to be measured of the part to be measured on the fuel assembly onto which the laser is projected. The laser generators and the image collectors of all the probes are connected to the controller through cables. The image collector conveys the image information of the surface to be measured containing the laser collected to the controller. The controller receives the image information and processes and analyzes the working data of each probe, and can calculate the actual position of the laser based on the laser triangulation method to obtain the measurement result.

[0047] When the standard fuel assembly rotates, it rotates 90 degrees clockwise or counterclockwise.

[0048] Step S2: Then collect the data of the same two surfaces of the fuel assembly to be measured. First, collect the distances from the upper nozzle, the lower nozzle and the grid to the probe on one surface, and then rotate 90 degrees to collect the distances from the upper nozzle, the lower nozzle and the grid to the probe on the other surface;

[0049] When the fuel assembly to be measured rotates, it rotates 90 degrees clockwise or counterclockwise.

[0050] The data to be collected is shown in Table 1, where X is the distance from Surface 1 to the measurement probe and Y is the distance from Surface 4 to the measurement probe.

[0051] Table 1 Content of Data Collection for the Outer Contour of the Fuel Assembly

[0052]

[0053] Step S3: Calculate the reading offset of each layer of the positioning grid. The reading offset of the selected positioning grid is the distance between the fuel assembly to be measured and the probe minus the distance between the standard assembly and the probe;

[0054] Δ = Y - X.................(1)

[0055] In the above formula: Δ represents the reading offset, Y represents the distance between the fuel assembly to be measured and the probe, and X represents the distance between the standard assembly and the probe;

[0056] The calculation results of the reading offset of each layer of the positioning grid are shown in Table 2.

[0057] Calculation Results of Offset of Each Layer of Positioning Grid of Component to Be Measured in Table 2

[0058] Item Surface 1 of the component under test Surface 4 of the component under test Reading offset of the upper tube seat <![CDATA[Δ 1-1 = Y 1-1 - X 1-1 > <![CDATA[Δ 2-1 = Y 2-1 - X 2-1 > Reading offset of the first layer of grid <![CDATA[Δ 1-2 = Y 1-2 - X 1-2 > <![CDATA[Δ 2-2 = Y 2-2 - X 2-2 > Reading offset of the second layer of grid <![CDATA[Δ 1-3 = Y 1-3 - X 1-3 > <![CDATA[Δ 2-3 = Y 2-3 - X 2-3 > ... ... ... Reading offset of the Nth layer of grid <![CDATA[Δ 1-(N+1) = Y 1-(N+1) - X 1-(N+1) > <![CDATA[Δ 2-(N+1) = Y 2-(N+1) - X 2-(N+1) > Reading offset of the lower tube seat <![CDATA[Δ 1-(N+2) = Y 1-(N+2) - X 1-(N+2) > <![CDATA[Δ 2-(N+2) = Y 2-(N+2) - X 2-(N+2) >

[0059] In the table, Δ 1-1 is the reading offset of the upper nozzle during the measurement of surface 1 of the fuel assembly to be measured, Δ 1-2 is the reading offset of the first layer of grid during the measurement of surface 1 of the fuel assembly to be measured,..., Δ 1-(N+1) is the reading offset of the Nth layer of grid during the measurement of surface 1 of the fuel assembly to be measured, Δ 1-(N+2) is the reading offset of the lower nozzle during the measurement of surface 1 of the fuel assembly to be measured.

[0060] Δ 2-1 is the reading offset of the upper nozzle during the measurement of surface 4 of the fuel assembly to be measured, Δ 2-2 is the reading offset of the first layer of grid during the measurement of surface 4 of the fuel assembly to be measured,..., Δ 2-(N+1) is the reading offset of the Nth layer of grid during the measurement of surface 4 of the fuel assembly to be measured, Δ 2-(N+2) is the reading offset of the lower nozzle during the measurement of surface 4 of the fuel assembly to be measured.

[0061] Step S4: Taking the upper nozzle of the fuel assembly as the zero point, calculate the deformation of each layer of positioning grid. The deformation of each layer of positioning grid is the reading offset of this layer of positioning grid minus the reading offset of the upper nozzle.

[0062] A = Δ 定位格架 - Δ 上管座 ......................(2)

[0063] In the above formula, A is the deformation.

[0064] The calculation results of the deformation of each layer of positioning grid are shown in Table 3. Referring to Table 3, when A is positive in the table, it represents an offset in the positive direction of X or Y relative to the upper nozzle of the fuel assembly; conversely, when A is negative, it represents an offset in the negative direction of X or Y relative to the upper nozzle of the fuel assembly.

[0065] Table 3 Deformation of Each Layer of Positioning Grid of Component to Be Measured

[0066] Item Surface 1 of the component under test Surface 4 of the component under test Deformation of the upper tube seat <![CDATA[A 1-1 = 0]]> <![CDATA[A 2-1 = 0]]> Deformation of the first layer of grid <![CDATA[A 1-2 = Δ 1-2 - Δ 1-1 > <![CDATA[A 2-2 = Δ 2-2 - Δ 2-1 > Deformation of the second layer of grid <![CDATA[A 1-3 = Δ 1-3 - Δ 1-1 > <![CDATA[A 2-3 = Δ 2-3 - Δ 2-1 > ... ... ... Deformation of the Nth layer of grid <![CDATA[A 1-(N+1) = Δ 1-(N+1) - Δ 1-1 > <![CDATA[A 2-(N+1) = Δ 2-(N+1) - Δ 2-1 > Deformation of the lower tube seat <![CDATA[A 1-(N+2) = Δ 1-(N+2) - Δ 1-1 > <![CDATA[A 2-(N+2) = Δ 2-(N+2) - Δ 2-1 >

[0067] In the table, A 1-1 is the deformation of the upper nozzle during the measurement of surface 1 of the fuel assembly to be measured, A 1-2 is the deformation of the first layer of grid during the measurement of surface 1 of the fuel assembly to be measured,..., A 1-(N+1) is the deformation of the Nth layer of grid during the measurement of surface 1 of the fuel assembly to be measured, A 1-(N+2) is the deformation of the lower nozzle during the measurement of surface 1 of the fuel assembly to be measured.

[0068] A 2-1 is the deformation of the upper nozzle when measuring the surface 4 of the fuel assembly to be measured, A 2-2 is the deformation of the first grid when measuring the surface 4 of the fuel assembly to be measured, ……, A 2-(N+1) is the deformation of the Nth grid when measuring the surface 4 of the fuel assembly to be measured, A 2-(N+2) is the deformation of the lower nozzle when measuring the surface 4 of the fuel assembly to be measured.

[0069] Step S5: Select the two closest grids, connect the two grids into a straight line, and calculate the intermediate offset of each layer of positioning grids without deformation based on the offset of the two grids and considering the vertical position relationship of each layer of positioning grids of the fuel assembly in design;

[0070] Preferably, select the first grid and the second grid. Because the first grid and the second grid are the closest.

[0071] The calculation results are shown in Table 4. In the table: 1) Δ' is the intermediate offset; 2) d1 is the vertical distance from the upper nozzle to grid 1, d2 is the vertical distance from grid 1 to grid 2…d N+1 is the vertical distance between the (N - 1)th grid and the Nth grid, d N+2 is the vertical distance from the Nth grid to the lower nozzle.

[0072] Table 4 Calculation results of the intermediate offset of each layer of positioning grids of the component to be measured

[0073]

[0074] In the table, Δ′ 1-1 is the intermediate offset of the upper nozzle when measuring the surface 1 of the fuel assembly to be measured, Δ′ 1-2 is the intermediate offset of the first grid when measuring the surface 1 of the fuel assembly to be measured, ……, Δ′ 1-(N+1) is the intermediate offset of the Nth grid when measuring the surface 1 of the fuel assembly to be measured, Δ′ 1-(N+2) is the intermediate offset of the lower nozzle when measuring the surface 1 of the fuel assembly to be measured.

[0075] Δ′ 2-1 is the intermediate offset of the upper nozzle when measuring the surface 4 of the fuel assembly to be measured, Δ′ 2-2 is the intermediate offset of the first grid when measuring the surface 4 of the fuel assembly to be measured, ……, Δ′ 2-(N+1) is the intermediate offset of the Nth grid when measuring the surface 4 of the fuel assembly to be measured, Δ′ 2-(N+2) is the intermediate offset of the lower nozzle when measuring the surface 4 of the fuel assembly to be measured.

[0076] Step S6: Calculate the corrected deformation of each layer of positioning grids of the fuel assembly by subtracting the intermediate offset from the reading offset;

[0077] B = Δ - Δ'................(3)

[0078] In the above formula: B represents the corrected deformation amount.

[0079] The calculation method of the corrected deformation amount of each layer of positioning grid of the component to be measured is shown in Table 5. According to the calculation results in Table 5, when B is positive, it means that the positioning grid deviates in the positive direction of X or Y; on the contrary, when B is negative, it means that it deviates in the negative direction of X or Y relative to the upper nozzle of the fuel assembly.

[0080] Table 5 Corrected deformation amount of each layer of positioning grid of the component to be measured

[0081] Item Surface 1 of the component under test Surface 4 of the component under test Corrected deformation of the upper tube seat <![CDATA[B 1-1 = Δ 1-1 - Δ′ 1-1 > <![CDATA[B 2-1 = Δ 2-1 - Δ′ 2-1 > Corrected deformation of grid 1 <![CDATA[B 1-2 = Δ 1-2 - Δ′ 1-2 > <![CDATA[B 2-2 = Δ 2-2 - Δ′ 2-2 > Corrected deformation of grid 2 <![CDATA[B 1-3 = Δ 1-3 - Δ' 1-3 > <![CDATA[B 2-3 = Δ 2-3 - Δ′ 2-3 > ... ... ... Corrected deformation of grid N <![CDATA[B 1-(N+1) = Δ 1-(N+1) - Δ' 1-(N+1) > <![CDATA[B 2-(N+1) = Δ 2-(N+1) - Δ′ 1-(N+1) > Corrected deformation of the lower tube seat <![CDATA[B 1-(N+2) = Δ 1-(N+2) - Δ′ 1-(N+2) > <![CDATA[B 2-(N+2) = Δ 2-(N+2) - Δ′ 1-(N+2) >

[0082] In the table, B 1-1 is the corrected deformation amount of the upper nozzle when measuring the surface 1 of the fuel assembly to be measured, B 1-2 is the corrected deformation amount of the first layer of grid when measuring the surface 1 of the fuel assembly to be measured,..., B 1-(N+1) is the corrected deformation amount of the Nth layer of grid when measuring the surface 1 of the fuel assembly to be measured, B 1-(N+2) is the corrected deformation amount of the lower nozzle when measuring the surface 1 of the fuel assembly to be measured.

[0083] B 2-1 is the corrected deformation amount of the upper nozzle when measuring the surface 4 of the fuel assembly to be measured, B 2-2 is the corrected deformation amount of the first layer of grid when measuring the surface 4 of the fuel assembly to be measured,..., B 2-(N+1) is the corrected deformation amount of the Nth layer of grid when measuring the surface 4 of the fuel assembly to be measured, B 2-(N+2) is the corrected deformation amount of the lower nozzle when measuring the surface 4 of the fuel assembly to be measured.

[0084] Step S7: Calculate the maximum value of the absolute offset of the positioning grid of the fuel assembly;

[0085] The maximum deformation amount of the fuel assembly refers to the maximum value of the absolute offset of the positioning grid of the fuel assembly. B max = max(|upper nozzle deformation amount|, |grid 1 deformation amount|,..., |lower nozzle deformation amount|) (4);

[0086] In formula 4, B max is the maximum deformation amount of the fuel assembly.

[0087] Step S8: Calculate the corrected deformation amount of the lower nozzle relative to the upper nozzle, using the deformation amount of the lower nozzle minus the deformation amount of the upper nozzle.

[0088] B 下管座-上管座 = B 下管座 - B 上管座.......................(5)

[0089] The deformation of the lower socket relative to the upper socket is positive, which is equivalent to the lower socket deviating in the positive X or Y direction relative to the upper socket; conversely, the deformation of the lower socket relative to the upper socket is negative, which is equivalent to the lower socket deviating in the negative X or Y direction relative to the upper socket.

[0090] The calculation result of the fuel assembly contour correction can be used to guide the core positioning operation of the fuel assembly, reduce the risk of fuel operation, improve operation efficiency, and save overhaul time. When

[0091] The embodiment of the present invention also discloses a method for determining the influence of the fuel assembly contour deformation on loading, including the following steps:

[0092] Step S1: Calculate the correction deformation using the method described in the above technical solution;

[0093] Step S2: Determine the calculated correction deformation.

[0094] If the following two conditions are simultaneously met, there will be difficulties in the core positioning operation of the fuel assembly, and it is necessary to consider in advance the fuel assembly loading operation plan to help the fuel assembly with large deformation be successfully positioned;

[0095] Condition 1: The correction deformation of the lower socket of the fuel assembly relative to the upper socket is greater than the radius of the positioning hole of the lower socket;

[0096] Condition 2: The lower socket of the fuel assembly deviates in the R direction relative to the upper socket, and when the core is positioned, the R direction is an empty position.

[0097] Illustrate with an example:

[0098] The radius of the positioning hole of the lower socket of the fuel assembly is 10 mm. The lower socket of the fuel assembly F deviates 20 mm in the positive Y direction relative to the upper socket, and there is no fuel assembly in the positive Y direction when the fuel assembly F is positioned. The fuel assembly F simultaneously meets the above Condition 1 and Condition 2. Therefore, there will be difficulties in the core positioning operation of the fuel assembly F, and it is necessary to consider in advance the loading operation plan.

[0099] The calculation result of the fuel assembly contour correction can be used to guide the core positioning operation of the fuel assembly, reduce the risk of fuel operation, improve operation efficiency, and save overhaul time. When the correction deformation of the lower socket of the fuel assembly relative to the upper socket is large and the following two conditions are simultaneously met, there will be difficulties in the core positioning operation of the fuel assembly, and it is necessary to consider in advance the fuel assembly loading operation plan to help the fuel assembly with large deformation be successfully positioned.

[0100] The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0101] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for correcting the calculation of the contour of a fuel assembly, characterized in that It includes the following steps: Step S1: Use the fuel assembly contour measuring device to first collect the distances between the upper nozzle, the lower nozzle, and the spacer grid and the probe on one surface of the undeformed standard fuel assembly, and then rotate 90 degrees to collect the distances between the upper nozzle, the lower nozzle, and the grid and the probe on the other surface. Step S2: Then collect the data of the same two surfaces of the fuel assembly to be measured. First, collect the distances between the upper nozzle, the lower nozzle, and the grid and the probe on one surface, and then rotate 90 degrees to collect the distances between the upper nozzle, the lower nozzle, and the grid and the probe on the other surface. Step S3: Calculate the reading offset of each layer of spacer grid. Step S4: Compare the reading offsets of each layer of spacer grid and the upper nozzle, and calculate the deformation of each layer of spacer grid. Step S5: Select two adjacent layers of grids, connect the two layers of grids into a straight line, and based on the offsets of the two grids, consider the vertical position relationship of each layer of spacer grid in the fuel assembly in design, and calculate the intermediate offset of each layer of spacer grid without deformation. Step S6: Use the reading offset and the intermediate offset to calculate the corrected deformation of each layer of spacer grid in the fuel assembly, and obtain the maximum corrected deformation of the fuel assembly. Step S7: Calculate the corrected deformation of the lower nozzle relative to the upper nozzle.

2. The correction calculation method for the contour of the fuel assembly according to claim 1, characterized in that, In the step S3, the reading offset of the selected spacer grid is the distance between the fuel assembly to be measured and the probe minus the distance between the standard assembly and the probe.

3. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, wherein In the step S4, the deformation of each layer of spacer grid is the reading offset of this layer of spacer grid minus the reading offset of the upper nozzle.

4. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, wherein In the step S5, select the first layer of grid and the second layer of grid, and connect the first layer of grid and the second layer of grid into a straight line.

5. The method for correcting the calculation of the fuel assembly contour according to claim 1, characterized in that In the step S5, The intermediate offset of the upper nozzle Δ′1 = Δ1 - d1*(Δ3 - Δ2) / d2; The intermediate offset of the first layer of grid Δ′2 = Δ2; The intermediate offset of the second layer of grid Δ′3 = Δ3; The intermediate offset Δ′ of the Nth layer grid (N+1) =(d2 +... + d N ) * (Δ3 - Δ2) / d2 + Δ2; Middle offset Δ′ of the lower socket (N+2) =(d2 +... + d N+1 ) * (Δ3 - Δ2) / d2 + Δ2; Among them, Δ' is the intermediate offset; d1 is the vertical distance from the upper tube seat to the first layer of grid, d2 is the vertical distance from the first layer of grid to the second layer of grid... d N+1 is the vertical distance between the (N - 1)-th layer of grid and the N-th layer of grid, d N+2 is the vertical distance between the N-th layer of grid and the lower tube seat; Δ is the reading offset, and N is a natural number.

6. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, characterized in that In the step S6, the corrected deformation is the reading offset minus the intermediate offset.

7. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, characterized in that, In the step S6, the maximum corrected deformation amount of the fuel assembly is B max ; B max = max(|Upper tube seat deformation|, |Deformation of the Nth layer grid|,..., |Lower tube seat deformation|) (4); In formula 4, N is a natural number.

8. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, characterized in that, In the step S7, the corrected deformation of the lower nozzle relative to the upper nozzle is the corrected deformation of the lower nozzle minus the corrected deformation of the upper nozzle.

9. The method for correcting and calculating the outer contour of the fuel assembly according to claim 1, characterized in that, In the step S1, the fuel assembly contour measuring device uses a laser probe, and each of the upper nozzle, the lower nozzle, and each layer of grid corresponds to a probe, and the probe is arranged parallel to the grid.

10. A method for determining the influence of the deformation of the outer contour of a fuel assembly on fuel loading, characterized in that, It includes the following steps: Step S1: Calculate the corrected deformation using the method described in any one of claims 1 to 9. Step S2: Judge the calculated corrected deformation. If the following two conditions are simultaneously met, there will be difficulties in the core positioning operation of the fuel assembly, and it is necessary to consider the fuel assembly loading operation plan in advance to help the fuel assembly with larger deformation to be positioned smoothly. Condition 1: The corrected deformation of the lower nozzle of the fuel assembly relative to the upper nozzle is greater than the radius of the positioning hole of the lower nozzle. Condition 2: The lower nozzle of the fuel assembly is deflected relative to the upper nozzle in the R direction, and when the core is positioned, the R direction is an open position.

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