JPS58124987A - Control rod operation guide device for atomic power plant - 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 [Technical Field of the Invention] The present invention provides a method for controlling coolant flow rate and controlling a control rod by controlling a coolant flow rate and controlling a control rod.
The present invention relates to a control rod operation guide device for a nuclear power plant that predicts the neutron distribution within the reactor of a nuclear power plant that controls reactor output and guides control rod operation based on this prediction.

[Technical background of the invention]

During the operation of a boiling water reactor (BWR) plant, the following three detector regions are passed between startup and reaching the rated output level.

(a) SRM (5source range mo
(b) I RM (Intermediate run)
ge monitor) area Area from near criticality to low output level (c) APRM (Average power ra
nge monitor) area All areas from low output level to high output level Among these detector areas, the IRM area requires the most attention from the operator. In other words, is the temperature increase rate in the furnace constant in this region? It is necessary to operate the @ stick, and it is necessary to switch wrenches between multiple IRMs.

[Problems with background technology]

Operators must frequently switch the IRM wrench as described above as they operate the control rods.

Furthermore, if the timing of wrench switching is missed, a reactor scram will occur, so careful attention must be paid to the timing.

Furthermore, if the IRM range is switched prematurely, the scale becomes smaller and there is a risk that the control rod will be blocked from being pulled out. Further, although the IRM instruction value increases immediately after the control rod is operated, the IRM instruction value may decrease thereafter as the temperature rises. Therefore, when changing the wrench at a stage where the indicated value is small relative to the scale, the wrench down,
This means that one of the range knobs must be selected, which increases the complexity of switching wrenches.

Therefore, it is not a good idea to switch the wrench at the bottom of the scale, and it is desirable to reduce the number of switches by switching at the bottom of the scale, but in this case, as mentioned above, the timing will be lost and the scale will be over may cause a reactor scram.

Conventionally, control rod operations and IRM range switching have relied on the experience and intuition of operators, but there is a need for the development of a device that can guide and accurately control control rod operations and wrench switching.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and each time a control rod is operated, it instructs the control rod core position and operation amount to be operated next time, and also determines whether it is necessary to change the IRM wrench as a result of the above operation. The objective is to obtain a control rod operation guide device that instructs the

[Summary of the invention]

In the present invention, each time a control rod is operated, the control rod core position and operation amount to be operated next are instructed, and the detector indication value is predicted from the reactor power distribution result associated with the operation, and the detector indication value is predicted from the current set value. The above objective is achieved by instructing the wrench to be switched depending on whether or not the detector stays within the range of a certain detector wrench.

[Embodiments of the invention]

In Figure 1, inside the reactor 1 are various detectors (not shown) that detect process variables such as the position of the control rods inserted in the reactor core, the neutron flux in the reactor core, the flow rate of coolant in the reactor, pressure, and temperature. The detected outputs, that is, the core data signal S1, are input to a core performance calculation device 2 that calculates the performance of the reactor core. This core performance calculation device 2 is constituted by a well-known electronic computer, and calculates the core performance based on the input core data signal S1.

The output signal S2, which is the calculation result of the core performance calculation device 2, is
It is given to the axial power distribution prediction device 3 and the two-dimensional furnace power distribution prediction device 4, and is used as initial value data by these devices. The axial power distribution prediction device 3 approximates the reactor core with an axial-dimensional diffusion model to quickly obtain the f4'5 reactor power distribution based on control rod position changes with the necessary accuracy. It has the same configuration as the device disclosed in Japanese Patent Application No. 55-89001.

The two-dimensional reactor power distribution prediction device 4 is a core performance calculation device 2.
Input the two-dimensional reactor power distribution corresponding to the installation of the IRM detection detector, normalize the two-dimensional reactor power distribution, and predict the reactor power distribution after control rod operation from the following calculation formula. That is,
In a nuclear reactor, the following diffusion equation holds.

Here, KH, Ji M 1. J i B 1. J
indicates the infinite multiplication factor, moving area, and axial buckling at nodes I and J, where the core height is the IRM detector position,
λ is the eigenvalue of the reactor, and φ is the neutron flux.

The axial leakage amounts Bl and J are determined by back calculation of equation (1). (2) The data transferred from the core performance calculation device 2 as described above. The total nuclear constant based on is calculated, and the neutron flux distribution in the reactor and the neutron flux distribution on the calculation formula match.

Changes in the neutron flux distribution after control rod operation can be determined by determining the nuclear constant for the control rod and repeatedly calculating equation (1).

Signal S of the absolute value of the prediction result of the axial output distribution prediction device 3
3 and IRM of the prediction results of the two-dimensional reactor power distribution prediction device 4
The signal S4 of the normalized reactor power distribution on the detection detector surface is input to the detector indication value prediction device 5, and the detector indication value prediction device 5 calculates whether the signal S3 or S4 is the neutron at the detector position. The neutron flux at the detector position is determined by combining the flux distributions. Furthermore, the neutron flux φ1 obtained here is converted into a detector indication value according to the following equation.

Ai = αφ1・・・・・・・・・・・・・・・・・・
(8) Here, A1 is the indicated value of the detector 1, and α is a conversion coefficient determined in consideration of the control rod position around the detector 1.

The control rod position designation device 6 receives a control rod position signal S of the reactor 1.
5, and from this signal S5 and the preset control rod withdrawal procedure, specify the core position and operation amount of the control rod to be operated next, and use the signal S6 regarding these to predict the axial reactor power distribution. Apparatus 3: Supply to the two-dimensional reactor power distribution prediction apparatus 4 and start them.

The control rod operation instruction device 7 receives the signal S6 and instructs the position and operation amount of the control rod to be operated, and also determines the wrench whose instruction value is currently set based on the output signal S7 of the detector instruction value prediction device 5. It determines whether or not it stays within the range, and if it deviates, it instructs to change the wrench.

In addition, 8 in FIG. 1 is a nuclear reactor operation panel, and a signal S8 related to detector wrench data set on this panel is given to the control rod operation instruction device 7.

Therefore, in the device of the present invention, when the operator operates a control rod, the control rod position specifying device 6 is automatically activated immediately after, and the position and operation amount of the control rod to be operated next are set. The instruction is given by the operation instruction device 7. At the same time, the data on the control rod operations are delivered to the axial reactor power distribution device 3 and the two-dimensional reactor power distribution prediction device 4, and these devices are started up and The detector indication value prediction device 5 predicts the detector indication value based on the prediction results of both the devices 3 and 4.

The control rod operation instruction device determines whether or not it is necessary to change the currently set detector wrench based on the prediction result of the detector instruction value prediction device 5, and instructs the change if necessary.

Therefore, it is most preferable in terms of accuracy to predict the reactor power distribution by performing three-dimensional calculations, but three-dimensional calculations require a long calculation time and are not suitable for online prediction. In the present invention, the axial reactor power distribution prediction and the two-dimensional reactor power distribution prediction are combined to approximate three-dimensional calculations in order to shorten the calculation time, but the prediction accuracy is as shown in Figure 2. . That is, in FIGS. 2A and 2B, the inserted state of the control rod is shown in a grid, where blanks in the grid indicate that the control rod is fully withdrawn, and O indicates that the control rod is fully inserted. Figure 2C shows the predicted neutron flux distribution when the state in Figure 2A changes to the state in Figure 2B, that is, when the control rods (9, 8) in Figure 2A are fully inserted. ing. From this figure, it can be seen that the drop in neutron flux at the operated control rod core position (9.8) and the surrounding core positions is approximately the same between the predictions made by the present invention and the predictions made by cubic calculation. Recognize. It can be seen that almost the same prediction results are obtained at other core locations. Therefore, it is recognized that the apparatus of the present invention can obtain prediction accuracy that is almost the same as prediction by three-dimensional calculation.

〔Effect of the invention〕

According to the present invention, each time a control rod is operated, the core position and operation amount of the control rod to be operated next are instructed, and it is also instructed whether or not to change the IBM wrench as a result of the control rod operation. There is no risk of various inconveniences occurring due to premature range switching.Furthermore, as a result of being instructed to switch the wrench as described above, the mental burden on the operator is significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
Figures A and B are control rod pattern diagrams, and Figure 2C is a graph for explaining the present invention in detail. 1. Nuclear reactor, 2. Core performance calculation device,
3... Axial power distribution prediction device, 4... Two-dimensional reactor power distribution prediction device, 5... Detector indication value prediction device, 6. Control rod position indicating device, 7... Control rod operation instruction Device, S, ~S8...Signal 11-

Claims (1)

[Claims] Calculates core performance based on plant data obtained from various detectors that detect the position of control rods inserted into the reactor core, neutron east inside the reactor core, process quantities inside and outside the core, etc. an axial reactor power distribution prediction device that predicts an axial reactor power distribution based on an axial-dimensional diffusion model using data output by the core performance calculation device; A two-dimensional reactor power distribution prediction device that predicts a reactor power distribution in a height plane of a neutron detector using data output by the device, and the axial reactor power distribution prediction device and the two-dimensional reactor power distribution prediction device. The neutron flux distribution at the detector position is synthesized from the neutron flux distribution by
A detector indication value prediction device that converts into a detector signal, the detector range data set on the reactor operation panel, and the detector indication value 1- Range switching information and control to be operated from the results of the sub-device A control rod operation guide device for a nuclear power plant, comprising a control rod operation instruction device that provides rod information.