JP3340251B2 - Digital control rod pull-out monitoring system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital control rod withdrawal monitoring system which is used for monitoring the power range of a nuclear reactor and which can control a plurality of control rods simultaneously.

[0002]

2. Description of the Related Art A control rod pull-out monitoring system (hereinafter referred to as "R
BM) are located in the containment vessel and are numbered in the vicinity of one hundred and several hundred control rods (the number depends on the maximum output value of the reactor). The number of installations differs depending on the maximum output value of the LPRM detector), an LPRM detector signal around the control rod for starting the withdrawal or insertion operation is selected and its average value is determined, and the average value around the control rod to be withdrawn or inserted is obtained. When the reactor output (local output) is abnormally high (or low), an alarm such as a rod block signal is generated to protect the reactor. Such RBM
Requires high reliability and high-speed response.

Currently operating nuclear reactors use analog RBMs. The analog RBM is configured to monitor the removal or insertion of one control rod at a time. Each split counter is used in the LPRM detector, and outputs a neutron flux detection signal as an LPRM detector signal. This neutron flux signal can be converted into a reactor output value.

By the way, in the analog type RBM, one at a time
It is configured to monitor the removal or insertion of one control rod. However, in order to reduce the start-up and shutdown time of the reactor, it is necessary to be able to simultaneously withdraw / insert multiple control rods. No. In fact, the reactor currently under construction (AB
WR) is designed on the assumption that a plurality of control rods are simultaneously pulled out.

In order to monitor simultaneous pull-out of a plurality of control rods using the above-mentioned analog RBM, in order to satisfy high reliability and high-speed response, the number of control rods to be simultaneously pulled out is controlled by the number of control rods. The formula RBM must be installed.

In the RBM, an RBM gain, which is a correction value for calculating an RBM value in a null sequence process, is calculated from an average value of LPRM detector signals around a selected control rod and an average reactor output (APRM value). ing. Such null sequence processing needs to be performed every time the pull-out control rod is changed. In the case of the analog type RBM, R
Null sequence processing units are required for the number of BMs.

The RBM value is obtained by averaging the LPRM detector signals around the selected control rod, and converting the average value into a correction value (R
BM gain). The reactor power is monitored using the RBM value.

[0008]

However, in order to monitor the simultaneous withdrawal of a plurality of control rods using the analog RBM, as described above, a plurality of analog RBMs are required.
As the number of RBMs increases, a transmission line for transmitting pull-out control rod information to each RBM and a null sequence processing unit are required in the same manner, and thus the problem that the whole system becomes large and complicated. is there. In addition, when the number of control rods for simultaneous pulling control is not the maximum, there are RBMs that are not operated, resulting in poor system efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and allows a plurality of control rods to be simultaneously pulled out and monitored without increasing the size and complexity of the system, thereby reducing costs and improving maintainability. It is an object of the present invention to provide a control rod withdrawal monitoring system that can perform the control.

[0010]

In order to achieve the above object, the present invention takes the following measures. The present invention processes a detection signal of a neutron flux detector around a control rod that is controlled to be pulled out of control rods arranged in a reactor, and the reactor output around the control rod has a fluctuation exceeding an allowable range. In a digital control rod pull-out monitoring system that generates an alarm, a control rod pull-out device that pulls out control rods is provided in the control rod pull-out device, at least the leading data indicating the beginning of valid data, the position data of the pull-out control rod, Control rod information creating means for creating frame data for all of the extraction control rods, including a frame number indicating the number of the control rod among the serial numbers assigned to the extraction control rods, and end data indicating the end of valid data; Serial data transmitting means for sequentially transmitting the frame data generated by the control rod information generating means as a frame data sequence repeatedly; A frame data string is provided from the control rod information creating means via the serial data transmission means, and the frame data of each of the pull-out control rods is input from the frame data string. Control rod information receiving means to be taken out, a storage unit for storing frame data of each pull-out control rod taken out by the control rod information receiving means, and a storage unit when the frame data stored in the storage unit exceeds a predetermined number. And a null sequence judging means for judging the necessity of the null sequence process by rearranging the frame sequence in the order of the frame number and comparing the frame sequence with the previous frame sequence.

[0011]

[0012]

The present invention has the following effects by taking the above measures. According to the present invention, the leading data indicating the beginning of valid data in the control rod information creating means provided in the control rod extracting device for performing the control rod extracting operation,
The frame data consisting of the position data of the pull-out control rods, the frame number indicating the control rod number among the serial numbers assigned to all the pull-out control rods, and the end data indicating the end of the valid data are all the pull-out control rods. And the created frame data is sequentially and repeatedly transmitted as a frame data sequence by the serial data transmission means.

On the other hand, on the system body side separated from the control rod extracting device, a frame data string serially transmitted from the control rod information generating means via the serial data transmitting means is input to the control rod information receiving means. And
Frame data of each pull-out control rod is extracted from the frame data string. Therefore, on the system body side, control rod information on all the pull-out control rods can be acquired, and one R
With the BM, simultaneous pullout monitoring of a plurality of control rods can be performed.

Further, the frame data of each pull-out control rod extracted by the control rod information receiving means is stored in the storage unit of the system body. If the number of frame data stored in the storage unit exceeds a predetermined number, for example, the assumed maximum number of simultaneous pull-out control rods, frame data is extracted from the storage unit and a frame sequence arranged in the order of reception is a frame sequence. Sorted in numerical order. The rearranged frame sequence is compared with the previous frame sequence. If the two frame sequences are different, it means that the selection control rod has changed, so that the null sequence process is executed.

[0015]

Embodiments of the present invention will be described below. FIG. 1 is a diagram showing schematic functional blocks of an RBM system according to an embodiment of the present invention. In the present embodiment, a digital RBM 2 is connected to a control rod extracting device 1 that performs an actual control rod extracting operation via a control rod information transmission path 3-1.
Reactor LPRM (Reactor Local Power) Value and APRM
LPRM / AP monitoring (reactor average power) value
The RM unit 4 is similarly connected to the digital RBM 2 by the transmission line 3.
-2.

The control rod pulling-out device 1 has a data editing unit 5 for editing the control rod information instructed to the device main body into serial transmission data having a data structure shown in FIG. 2, and a transmission data created by the data editing unit 5. And a data transmission unit 6 for serially transmitting the control rod information as control rod information to the control rod information transmission path 3-1.

The digital RBM 2 includes an input interface unit 7 connected to the control rod information transmission line 3-1; an input interface unit 8 connected to the transmission line 3-2;
An operation unit 9 having various processing functions inherent to the BM;
And an output interface unit 10 for outputting the processing result of the above to the outside in the form of an alarm or the like. The operation unit 9 includes the CPU 1
1, a RAM 12, and the like. The CPU 11 implements a unique function by executing processing based on the flowcharts shown in FIGS. 3 to 5 in addition to the functions described above. Also, R
The AM 12 includes a data storage area for storing control rod information sent from the control rod extraction device 1, an area counter indicating a storage area (memory address) of the data storage area, a data update counter indicating update information of the data storage area, and the like. Are formed. FIG. 6 shows a memory configuration of a data storage area formed in the RAM 12. In the data storage area, control rod information described later is stored for each area.

Next, the operation of the embodiment constructed as described above will be described. In the data editing unit 5 of the control rod drawing device 1, frame data 1 to frame data N for each control rod are created corresponding to the assumed maximum number of simultaneous pulling control rods (N). These frame data 1 to N are shown in FIG.
The data is transmitted from the data transmission unit 6 to the digital RBM 2 as serial data as shown in FIG.

Here, one frame data is shown in FIG.
As shown in FIG. 2 (b), the frame is composed of M frames, and one frame is composed of head data indicating the start of the frame, and X in the reactor of a control rod for pulling out, as shown in FIG. 2 (c).
It is composed of coordinates and Y coordinates, the number of selected control rods, a frame number, and end data indicating the end of the frame.

Whenever the control rod selected by the control rod pull-out device 1 changes, the data editing section 5 of the control rod pull-out device 1 edits the frame data again to renew the new frame data 1 to frame. Data N is transmitted serially.

Further, for example, the maximum number N of simultaneous pull-out control rods
In the case of 8, if the currently selected number of control rods is 3,
Zero data is inserted into the coordinates of the pull-out control rods of the frame data allocated to the non-selected control rods. If no control rod is selected, the control rod non-selection signal is transmitted to the digital RBM 2 in a transmission frame.

On the other hand, the digital RBM 2 processes the serial data input from the control rod extracting device 1 to the input interface unit 7 based on the flowchart shown in FIG. That is, M per frame data i
Although a number of frames are input serially, a data frame is received when the same frame is repeated r times (r <M) (step S1).

For example, in a case where one frame data is composed of five frames, and a frame is adopted when the data is repeated three times, there is an opportunity to read the data three times. That is, (1) when the first three frames match,
(2) When the second to fourth frames match, (3) 3
This is when the fifth to fifth frames match. If the first three frames match, the fourth and fifth frames need not be confirmed, so the fourth and fifth frames are ignored and time is spent processing those data. I will not.

Next, it is determined whether or not the frame adopted in step S1 is abnormal (step S2). For example,
If the received frame and the frame pattern shown in FIG. 2C do not match, it is determined that the received frame is abnormal, and a predetermined abnormal process is executed (step S11).

If it is determined in step S2 that the received frame is normal, the type of the received frame is determined (step S2).
3). There are three types of frames: control rod data, unselected data, and zero data. If the coordinate data of the control rod for pulling out the frame is included, it is recognized as the control rod data, and it is determined whether or not the number of selections registered in the received frame is the same as the previous time (step 4). If the selected number is not the same as the previous time, the control rod is newly increased or decreased, and the count value i of the area counter for specifying the storage area of the control rod information is cleared to zero (step S).
5) Store the frame in area i on the data storage area (step S6). If the selected number is the same as the previous one, the frame is stored in the area i designated by the area counter (step S6). When the data is stored in the area i on the data storage area, the count value of the data update counter is counted up (step S8).

FIG. 6 shows a memory configuration of a data storage area formed in the RAM 12. The frame is stored by making the area different for each frame data by the area counter.

When the number of currently selected control rods is smaller than the maximum number N of simultaneous pull-out control rods, zero data is included in the received frame depending on the frame data. In the process of step S3, if the received frame is zero data, the process shifts to step S1 to receive the next frame.

If a control rod non-selection signal is detected in the process of step S3, it is determined that the data is non-selected data, and the entire data storage area is cleared (step S9).
Increment the data update counter. Then, it waits for the next received frame.

The arithmetic unit 9 performs a null sequence determination process shown in FIG. That is, the number of frames stored in the data storage area is monitored, and more frame data than the maximum number N of simultaneous pull-out control rods (partly the same frame data is stored) are stored in the data storage area. When the number L of frame data becomes L> N (step Q1), L frames are taken out from the data storage area (step Q2) and rearranged in the order of frame numbers registered in each frame (step Q3). . At this time, if the same frame number exists, the latest frame is left.

After the rearrangement, the frame sequence at the time of the previous null sequence determination is compared with the current frame sequence (step Q4). If there is no change in the selection control rods, the frame sequence is the same. If there is a change in the selection control rods, the frame sequences are different. If there is a change in both frame sequences, a null sequence is executed (step Q5). An example of the null sequence processing is shown below. If the average value of the peripheral LPRM signal values ≧ APRM signal value,
RBM gain = 1.0 If average value of peripheral LPRM signal values ≧ APRM signal value, RBM gain = (APRM signal value) / (average value of peripheral LPRM signal values) Note that peripheral LPRM signal values are subject to null sequence processing. Is determined, the peripheral LPRM detector is uniquely determined from the core map shown in FIG.
An average value can be obtained by selecting the signal of the detector.

When the RBM gain is newly calculated by the null sequence processing, the RBM gain is used for correcting the corresponding peripheral LPRM signal value. Further, in the arithmetic unit 9, the abnormality determination process shown in FIG. 5 is executed at regular intervals. This is because when the processing is interrupted continuously for T seconds (step R1), it is determined whether or not the data update counter has been updated (step R2). (Step R3).

As described above, according to the present embodiment, selected control rod information having the frame data number of at least the maximum simultaneous pulling control rod number is serially transmitted from the control rod pulling device 1, and the digital RBM 2 transmits a plurality of frame data of a plurality of frame data. Since only the control rod data is selected and stored from among them, the frame data corresponding to the maximum number of simultaneous pull-out control rods can be transmitted to the digital RBM 2 through one transmission path 3-1. A plurality of pieces of selection control rod information can be received. Therefore, while maintaining high reliability and high-speed response without increasing the number of transmission paths and RBM2,
Withdrawal monitoring of a plurality of control rods can be performed, so that the system configuration can be simplified and the cost can be reduced.

According to the present embodiment, the frames related to the respective selection control rods are transmitted continuously M times, and are adopted when the frames are repeated r times (M> r) in the digital RBM2. It is resistant to disturbance noise and the like, and highly reliable information transmission is possible.

According to the present embodiment, the necessity of the null sequence processing is determined when the number of frames L stored in the digital RBM 2 becomes L> N, and the necessary null sequence processing is performed when the selection control rod changes. Since this is performed, the null sequence processing of all the selected control rods can be performed in one null sequence section. The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0035]

As described in detail above, according to the present invention, a plurality of control rods can be simultaneously pulled out and monitored without increasing the size and complexity of the system, thereby achieving cost reduction and improvement in maintainability. A control rod withdrawal monitoring system can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a digital RBM system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an entire configuration of a serial data string used for transmitting control rod information in the digital RBM system shown in FIG. 1, a frame configuration of one frame data, and a data configuration in one frame.

FIG. 3 is a flowchart of a control rod information receiving process in the digital RBM system shown in FIG. 1;

FIG. 4 is a flowchart of a null sequence determination process in the digital RBM system shown in FIG.

FIG. 5 is a flowchart of an abnormality determination process in the digital RBM system shown in FIG.

FIG. 6 is a memory configuration diagram of a data storage area.

FIG. 7 is a diagram showing a reactor map.

[Explanation of symbols]

1 ... Control rod pull-out device, 2 ... Digital RBM2, 3-
DESCRIPTION OF SYMBOLS 1 ... Control rod information transmission line, 4 ... LPRM / APRM unit, 5 ... Data editing part, 6 ... Data transmission part, 7, 8 ... Input interface part, 9 ... Calculation part, 10 ... Output interface part, 11 ... CPU, 12 RAM12.

Claims (1)

(57) [Claims] A detection signal of a neutron flux detector around a control rod, which is controlled to be pulled out of control rods disposed in the reactor, is subjected to signal processing, and fluctuations of the reactor power around the control rod exceed an allowable range. In a digital control rod withdrawal monitoring system that generates an alarm if any, a control rod withdrawal device that performs control rod withdrawal work is provided with at least the first data indicating the beginning of valid data,
The position data of the pull-out control rod, the frame number indicating the number of the control rod among the serial numbers assigned to all the pull-out control rods, and the frame data including the end data indicating the end of the valid data are all extracted control rods. Control rod information creating means for creating, a serial data transmitting means for sequentially transmitting the frame data created by the control rod information creating means as a frame data sequence, and a system body side separated from the control rod extracting device. A control rod information receiving means for receiving a frame data string from the control rod information creating means via the serial data transmission means and extracting frame data of each pull-out control rod from the frame data string; A storage unit for storing frame data of each pull-out control rod taken out by the receiving means; When the number of frame data stored in the storage unit exceeds a predetermined number, the frame data is taken out from the storage unit, the frame sequence is rearranged in the order of the frame number, and a null sequence is determined by comparing with the previous frame sequence. A digital control rod pull-out monitoring system, comprising: a sequence determination unit.