JPS59690A - Control rod operation process indicating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control rod operation procedure display device, and more particularly, to a control rod operation procedure display device, which is capable of quickly starting and stopping a nuclear reactor without the control rod operation being blocked by a control rod withdrawal prevention monitor. The present invention relates to a control rod operation procedure display device that searches for and displays control rod operation procedures suitable for implementation.

In a boiling water reactor, several hundred fuel assemblies are loaded into the reactor to form the reactor core, and the output of the reactor is controlled by inserting over a hundred control rods between the fuel assemblies. is being adjusted. Furthermore, each control rod can be inserted and removed in dozens of steps from the fully inserted position to the fully withdrawn position. These control rods adjust the neutron flux distribution of the fuel assembly, prevent a local increase in the output of the fuel assembly, prevent damage to the fuel, and keep the reactor in a stable state. Therefore, when starting or stopping a nuclear reactor, if the control rods are operated in the wrong order, neutrons may be locally concentrated, causing fuel damage or an abnormal increase in the reactor's output. It is necessary to select and operate control rods in the correct order, with dozens of control rods and dozens of insertion/extraction positions. However, it is very difficult to select such a large number of control rods in a fixed order of operations and insert/remove them into predetermined positions, and there is a possibility of erroneous operation. Therefore, in recent years, a control rod operation procedure display device using a CR1 display device has been developed. The control rod operation procedure analyzed based on the reactor operation plan is stored in advance in a storage device, and the number of the control rod to be operated next (X-axis, Y-axis ) and insertion/removal position ft (N0T
In addition to displaying the control rod (indicated by CH), it is also determined whether the operated control rod was operated in the correct operating procedure, and in the case of an erroneous operation, an error is displayed. However, even when starting or stopping a nuclear reactor according to a plan analyzed in advance, there are often transient differences between the analysis results and the actual state of the reactor core. Therefore, even if the operator correctly operates the control rod according to the information on the control rod operation procedure display device, the control rod may not be controlled due to the interlock condition of the command height of the control rod withdrawal prevention monitor of the neutron instrumentation system. Rod operation is often blocked. In this case, it is necessary to temporarily suspend control rod operation and wait until the blockage is lifted. As a result, the operation time is long, the start or stop cannot be achieved within the scheduled time, there is a large deviation from the original operation plan, and the control rod operation procedure that has been analyzed and memorized in advance is If no changes are required, the control rod operation procedure display device will no longer be usable.

An object of the present invention is to provide a control rod operation j1 display device that allows an operator to smoothly and safely operate the control rods when starting and stopping a nuclear reactor.

A feature of the present invention is that, before displaying the control rod operation procedure, the instruction value of the control rod withdrawal prevention monitor after the control rod operation is predictively calculated,
By confirming that the set value that prevents control rod withdrawal is not exceeded, the control rod withdrawal prevention monitor prevents withdrawal when the operator performs the displayed control rod operation. Therefore, if you predict that the control rod withdrawal prevention monitor will prevent withdrawal if you follow the control rod operation procedure stored in advance, modify the control rod operation procedure so that the control rod withdrawal prevention monitor does not prevent withdrawal. Explore and view.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 2 is a system diagram of a control rod control device incorporating the control rod operation procedure display device of the embodiment shown in FIG. 1;

Local neutron detector (LPRM) installed inside reactor 1
The signal from 2 is calibrated by the neutron instrumentation device 4 and input to the control rod withdrawal prevention monitor 7 and the control rod operation procedure display device 9. The control rod 3 is driven by a control rod drive device 5. The control rod 3 insertion/removal position (NOTCH number) signal is
It is detected by a control rod position detector (not shown) and input to the control rod position information processing device 8. On the other hand, the operator selects the control rod 3 to be operated using the control rod manual operation device 6 and moves it to a predetermined insertion/removal position via the control rod drive device 5. At this time, the control rod withdrawal prevention monitor 7 averages the signals of the four local neutron detectors 2 in the axial direction of the IJ ring, and the value outputs the prevention signal. When the set point is exceeded, a blocking signal S is issued to prevent the control rod 3 from being pulled out any further. The control rod operation procedure display device 9 analyzes the control rod insertion/removal position signals received by the signal input section 9a, the local neutron detector signals, and the operation plan stored in the storage section 9b in advance. Using the control rod operation procedure, the calculation unit 9c and the control rod withdrawal prevention monitor 7
Calculate control rod operating procedures that do not exceed the blocking set point. The control rod operation procedure thus determined and the two-dimensional pattern of the control rod insertion/removal positions at the time of display are output by the display control section 9d to the CRT display 9e as a video signal. Therefore,
When the operator operates the control rod 3 according to the control rod operation procedure display device 9 according to this embodiment, the control rod withdrawal prevention monitor 7
The nuclear reactor can be started and stopped quickly and safely without being blocked by.

FIG. 2 is an example of a control rod operation procedure analyzed in advance based on the reactor operation plan. This control rod operation procedure is loaded in the storage section 9b of the control rod operation procedure display device 9. Further, within the same control rod operation procedure group number, the insertion/removal position limit value of each control rod 3 is assumed to be the same value. When withdrawing the control rods 3, the basic operation is to operate the control rods in order from the lowest group number when all control rods 3 are fully inserted, and within the same group number, from the lowest step number within the group. It is a procedure. However, the intra-group step numbers are temporarily attached for convenience of operation, and the order is not regulated during actual control rod operation. Therefore, even if the order of the control rods 3 to be operated within the same control rod operation procedure group is modified, it is still within the allowable range of the operation plan.

During actual operation of a nuclear reactor 1, a local neutron flux imbalance occurs temporarily due to the asymmetry of the control rod pattern. If the pull-out prevention monitor 7 is prevented, there may be a case where the operation must be interrupted. In this case, if the order of control rod operations is changed, the control rod withdrawal prevention monitor 7 is often not prevented. For this reason, in this embodiment, the search range includes changing the order of control rod operations within the same control rod operation procedure group. That is,
In the control rod operation procedure group number 30 in Fig. 2,
Control rod number (26-27) (34-27) (34-35
) (26-35) on the control rod withdrawal prevention monitor 7.
The goal is to search without being blocked.

FIG. M3 is a chart 70 of the control rod operation procedure search process executed in the calculation unit 9C of the control rod operation procedure display device 9. Each block will be explained below.

[Block 11] The setting value at which the control rod withdrawal prevention monitor 7 issues a prevention signal is determined as a linear function of the recirculation flow rate.

RL=α・FR×β ・・・・・・・・・m
Here, RL is the RBM blocking setting, F'fL is the recirculation flow rate, and α and β are constants. The recirculation flow rate is the flow rate of cooling water flowing through the core of the nuclear reactor 1.

[Block 12] Find the control rod operation procedure group number GM that includes the control rod operation to be displayed next based on the current control rod pattern. For example, in the case of control rod withdrawal, the control rod operations are accumulated according to the control rod operation procedure stored in advance from the state where all control rods 3 are fully inserted, and the control rod operations are compared with the current control rod pattern. Determine the lowest remaining group number.

[Block 13] Among the control rods 3 belonging to the group number GM, the control rods 3 that remain to be operated are arranged in the order of pre-stored step numbers within the group, numbered from 1 to N, and newly controlled. Create a bar operating procedure chart.

[Block 14] The control rod operation procedure chart created in block 13 is revised to an operation procedure chart that does not block the control rod withdrawal prevention monitor (RBkj) 7. FIG. 4 shows the search method. Here, regarding the calculation method of initial values and predicted values for nuclear thermal hydraulic calculation, refer to the local power distribution deformation prediction method for boiling water reactors (
The method proposed in Japanese Patent Application No. 48-94432) can be used. By applying this, the axial distribution of the traveling neutron detector (TIP) indicated value for each local neutron detector (LPRM) string after control rod operation can be obtained. By interpolating this with the positions of the four LPRMs installed in the axial direction! 0, LPRM indicated value LP (
L, J) can be obtained. The RBM reading RP shown in block 21 is calculated using the predicted value described above.

RP=MAX(RBMA, RBMB)...
...(2) 10R, LP (L, a) )/8 +RLP (L, 4)'J/8 Here, R, HMA is the RBM reading of A channel, RB
MB is the RBM reading of the B channel, L1 to L4 are the LPRM string numbers assigned to the operation control rods, R, LP
(L, J) is the LPR, M instruction value of string number L Lebel J.

Therefore, if the reading RP of the control rod withdrawal prevention monitor 7 after performing a control rod operation according to the operation procedure table does not exceed the set value RL for issuing a prevention signal, the control rod operation can be continued as is, and the next control Judgment is made for stick operation. R.P.
If exceeds RL, the order of operations is changed as shown in block 27 and the determination is made again. If the control rods are operated in the order listed in the operation procedure table, and it is confirmed that the control rod withdrawal prevention monitor's prevention signal setting value is not exceeded,
End the search process.

[Block 15] Display the operating procedure chart determined in block 14 on the CRT display 9e.
The data is transferred to the display control unit 9d for display on the screen.

Next, the display control unit 9d edits the control rod number and insertion/removal position limit value to be operated next from the operation procedure table along with the control rod pattern to be operated, and displays them on the CRT display 9e in the format shown in FIG. do. Figure 5 shows group number 300 control $26-
27 is moved from the insertion/removal position 40 to 4 and 6. 00 indicates that the control rods 3 are fully inserted, and as the number increases, the proportion of the control rods 3 that are being withdrawn from the core increases, and 48 indicates that the control rods 3 are fully withdrawn. In addition, in FIG. 5, complete extraction is indicated by a blank box.

According to the present invention, since it is possible to display control rod operation procedures that do not involve blocking the control rod withdrawal prevention monitor (BM), damage to fuel due to local concentration of neutrons and abnormal increase in reactor output can be prevented. It can be avoided. The control rod operation procedure that has been analyzed in advance is modified and displayed based on the actual reactor core state, allowing for flexible operation in line with the actual situation, and the time required to start and stop the reactor can be planned and synchronized. can be realized. When the operator performs the displayed operation, the operator's trust can be gained because the control rod withdrawal prevention monitor does not prevent the control rod from being withdrawn.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a control rod control device incorporating a control rod operation procedure display device according to an embodiment of the present invention, and FIG. 2 is a diagram showing control rods stored in the control rod operation procedure display device of FIG. An explanatory diagram showing the operation procedure, FIG. 3 is a chart 70 of the control rod operation procedure search process by the control rod operation procedure display device of FIG. 1, and FIG. 4 is a flowchart showing details of block 14 in FIG. 3.
FIG. 5 is an explanatory diagram showing a display example of the control rod operation procedure display device. 1... Nuclear reactor, 2... Local neutron detector, 3...
Control rod, 4... Neutron instrumentation device, 5... Control rod drive device, 6... Control rod manual operation device, 7... Control rod withdrawal prevention monitor, 8... Control rod position information processing equipment, 9.
...Control rod operation procedure display device, 9a...Signal input section,
9b...Storage unit, 9C...Calculation unit, 9d...Display control unit, 9e...CRT display. ! Jl Eye 20

Claims (1)

[Claims] 1. In a device that displays the operating procedure of multiple control rods that are pulled out and inserted into the fuel assembly in a sub-reactor to control the reactor output, the control rod withdrawal prevention monitor accompanying the displayed control rod operation. A means for predicting the reading and, if the predicted value exceeds a set value for preventing control rod withdrawal, a means for modifying a pre-stored control rod operating procedure and searching for a control rod operating procedure that falls within the set value. A control rod operation procedure display device, characterized in that the control rod operation procedure display device is provided.