CN1120502C - Address code measuring system for reactor control bar position - Google Patents

Abstract

An address code reactor control rod position measurement system is characterized in that: the distance between adjacent positioning coils is twice the control rod step length, and each positioning coil outputs a 1-bit code signal; the control rod drive shaft uses a non-magnetic Materials and magnetic materials are alternately arranged and processed, and the drive shaft is mechanically connected with the control rod to move synchronously. Treat the code output by the positioning coil as an address code, and the address code corresponds to the rod position. The rod position code signal and the coil fault signal are generated by a double-level comparator, and the fault detection of the rod position detector coil is realized. The invention correctly displays the position of the control rod, can be applied to the rod position measurement of the control rod of the cryogenic reactor and the pressurized water reactor, and can also be used for the measurement of the end point position of all reciprocating parts.

Description

Address Code Reactor Control Rod Rod Position Measuring System

technical field

The invention belongs to the field of nuclear reactors, in particular to the position measurement of nuclear reactor control rods and the measurement of the end points of all reciprocating parts.

Background technique

The present invention is an improvement of the Chinese patent CN92103620.5 "self-encoding digital rod position measuring system".

The reactor control rod system is one of the most important systems in nuclear reactor engineering. It is the only movable part in the nuclear reactor internals. The control rods are lifted or lowered to achieve neutron balance in the reactor core reaction process. Start-up, power regulation, steady-state operation and normal shutdown are all realized by control rods, and it is extremely important to correctly and reliably measure and indicate the position of the control rods in the reactor. The research on the measurement method of control rod position has been developing along with the development of nuclear reactor engineering. At present, the multi-coil-coil coding rod position measurement system widely used in pressurized water reactors and nuclear power plants is designed and manufactured according to US Patent US3858191.

Although the multi-coil-coil coding rod position measurement system is applicable to the current nuclear reactor engineering, its rod position detector has too many coils, and each coil can only detect a little position. In order to reduce the number of signal lead-out wires, the coils should be differentially connected in pairs according to Gray code coding, which makes the coil winding process of the rod position detector very complicated and prone to open circuit or short circuit faults. Secondly, since multiple coils are connected to each bit signal output line, the failure of one coil will lead to wrong rod position indication, and it is difficult for this system to detect a single coil fault in the rod position detector. The rod position detectors of pressurized water reactors and nuclear power plants are installed outside the pressure vessel, so it is easy for the staff to inspect and replace the rod position detectors. In recent years, starting from the safety of nuclear reactors, it is required to put the control rod drive mechanism and rod position detector into the pressure shell. The low temperature nuclear heating reactor built by Tsinghua University uses hydraulically driven control rods to realize the release How to implement the rod position detector into the stack is an urgent problem to be solved.

Chinese patent CN92103620.5 "Self-encoded digital rod position measurement system" rod position detector has few coils, and each signal line is a single coil output, so the coil winding process is very simple, and the rod position detector can be put into the stack Require. However, the rod position detector designed and manufactured according to this patent has a transition area, and the output code in the transition area coincides with the rod position true value code, resulting in an error display. Therefore, the self-encoded digital rod position measurement system is only suitable for the measurement of the end point position of the step-type moving parts, and it requires the step distance of the step-type motion to be larger than the transition zone of the rod position detector. Otherwise, an error display may appear.

Contents of the invention

The purpose of the present invention is to provide a rod position measurement system, which overcomes the shortcomings of the "self-encoded digital rod position measurement system", has the characteristics of no repeated codes and no code errors, and is suitable for the end point position measurement of step-by-step moving parts , It is also suitable for the measurement of the end position of continuous moving parts, and the position of the control rod is displayed correctly in the whole stroke of the control rod movement.

As shown in Figure 1, the present invention consists of a rod position detector 1, a signal transmitter 4, a data processing unit 10 and a display screen 11, wherein the rod position detector 1 includes a coil group 2 and a control rod drive shaft 3, and the coil group There are primary coils, compensation coils and N positioning coils in 2. The signal transmitter 4 includes an AC power source 9 , an amplification unit 5 , a rectification unit 6 , a comparison unit 7 and a switching level output unit 8 . It is characterized in that: the position measuring coil N in the above-mentioned coil group 2 is a positive integer not less than 5, and the distance between two adjacent position measuring coils is twice the step length between the control rod measuring points. The above-mentioned control rod drive shaft 3 is composed of segmented magnetically permeable materials and non-magnetically permeable materials arranged alternately, M is the number of odd-numbered segments including the first segment of material, _M1 is the number of even-numbered segments including the second segment of material, and the guide The relationship between the number of segments of magnetic material and non-magnetic material and the N of the positioning coil is: when N is an odd number, $m=\frac{1}{2}(N-1),$ when N is even $m=\frac{1}{2}(N-2);$ M ₁ =M-1. The length of the first section of material is A, and A is 3 times the step length of the control rod, and the length of each section of the same material as the first section is (A+4B) times the step length of the control rod, and B is a sequence of natural numbers starting from 1. The length of the last section of the same material as the first section is optional. The material other than the two ends of the drive shaft should be the same as that of the second section, and its length should be greater than 2N times the step length of the control rod.

The length of the second section of material and the same material as the second section thereafter satisfy the control rod step length of the relational expression [2(N-2)-A-4(B-1)]. The comparison unit 7 adopts a dual-level comparator, that is, a high-level comparator and a low-level comparator. The low-level comparator outputs a stick address signal, and the high-level comparator outputs a coil fault signal, thereby realizing N signal The coil outputs 2N switching level signals.

Coil group 2 includes 1 primary coil, N positioning coils and 1 compensation coil, N must be greater than 5, each coil is ring-shaped, installed above the drive shaft 3 movement track, outside the pressure cover, concentric with the drive shaft . The drive shaft is mechanically connected to the control rods and moves synchronously. When the drive shaft passes through the positioning coil, the position of the magnetically conductive material and the non-magnetically conductive material determines the output signal amplitude of the corresponding positioning coil, and the standard switching level is obtained after simple processing. That is: each positioning coil can output a binary code, and the output code of the coil group 2 corresponds to the position of the control rod. In the data processing unit 10, the output code of the coil group 2 is regarded as an address code, and 2 ^N byte addresses can be formed by the N-bit address bus, and the address code produced by the control rod bit is smaller than that formed by the N-bit address line In the address space, the address unit output by each stick bit stores the value of the stick bit of the control stick. We call the output code in the transition area "pseudo-code", and the pseudo-code also occupies an address, and the actual rod position value of the control rod is also stored in the pseudo-code address. An error display is generated, and the output code of the rod position detector 1 corresponds to the rod position of the control rod.

The spacing between adjacent coils in coil group 2 is twice the step size between the control rod measuring points, that is, the resolution of the detection rod position. The number of positioning coils is determined by the stroke and resolution of the control rod, that is to say, the number of positioning coils is determined by the number of required measuring points, but the number of positioning coils cannot be less than 5, and less than 5 cannot form magnetically conductive materials, non-magnetically conductive materials or Non-magnetic materials, magnetic materials are alternately arranged on the drive shaft, the upper limit of the number of positioning coils is not limited, it is completely determined by the number of measuring points required, in the control rod position measurement system of nuclear power plants, there are 7 or 8 positioning coils enough.

If the first section of the drive shaft 3 is a magnetically permeable material, then the minimum length of the magnetically permeable material section is 3 times the control rod step length, and the lengths of other parts are added up in increments of 4 times the control rod step length, that is, each section The length is 3 times the step length of the control rod, 7 times the step length of the control rod, 11 times the step length of the control rod, ... the number of segments of the magnetically permeable material is restricted by the number of coils N, and the number of segments of the magnetically permeable material M is related to that of the coil The number N has the following relationship: when N is an odd number $m=\frac{1}{2}(N-1)$ when N is even $m=\frac{1}{2}(N-2)$ The number of non-magnetic material segments is 1 less than the number of magnetic material segments, and the minimum length of the non-magnetic material is also 3 times the control rod step length. The length of other sections is also increased by 4 times the control rod step length. For a rod position detector containing N positioning coils, the length of the non-magnetic material section is correspondingly [2(N-2)-3] times the control Stick step size, [2(N-2)-7] times.... Controls the stick step size.

The driving shaft 3 can be designed according to the original code, and can also be designed according to the inverse code. The driving shaft 3 designed according to the inverse code can be exchanged with its corresponding magnetic-conductive material and non-magnetic-conductive material.

The primary coil of the coil group 2, the lead-out wires of the compensation coil and the position detection coil are directly connected with the signal transmitter 4. The signal transmitter 4 includes an AC power supply 9, an amplification unit 5, a rectification unit 6, a comparison unit 7 and a switching level output unit 8; wherein the AC power supply provides an excitation source for the primary coil of the rod position detector 1, a compensation coil and a position measuring unit. The output wires of the coils are all connected to the amplifying unit 5 of the signal transmitter 4 . The comparison unit 7 adopts a dual-level comparator, that is, a high-level comparator and a low-level comparator. The low-level comparator outputs a stick address signal, and the high-level comparator outputs a coil fault signal, thereby realizing N measurement The bit coil outputs 2N switching level signals. The switch level output unit 8 simultaneously outputs the rod position address signal and the coil fault signal. The rod position address signal and coil fault signal output by the signal transmitter 4 are directly connected to the data processing unit 10 . The data processing unit 10 is an intelligent circuit board, and its minimum system includes a central processing unit 8031, a program memory 2764, and an address latch 8282. In addition, it also has an input/output parallel interface 8255 and other necessary chips . The conversion from address code to display code is realized by software. Naturally, other intelligent data processing circuit boards can also be used.

The display codes and other display signals decoded by the data processing unit 10 are all sent to the display screen 11; various visualized bar position display devices can be designed according to requirements.

The invention has the advantages of reducing the number of coils of the rod position detector, simplifying the coil winding process, improving the reliability of the rod position detector, and correctly displaying the position of the control rod during the whole movement of the control rod, so that the rod position can be realized. In addition, the invention also realizes coil fault detection and alarm, ensuring the reliability of the entire rod position measurement system. It can not only be used for the rod position measurement of the low temperature reactor hydraulic drive control It is used for rod position measurement of PWR magnetic drive control rod system, and can also be used for end point position measurement of all reciprocating parts.

Description of drawings

Fig. 1 is a schematic diagram of the present invention.

Fig. 2 is a principle diagram of a rod position detector at a measuring point in embodiment 33 of the present invention.

Detailed ways

Embodiment 1: Fig. 2 is an embodiment of the present invention, a principle diagram of a rod position detector with 33 measuring points. The rod position measurement system of a certain nuclear power plant has 32 measuring points, which is designed according to the present invention. According to the number of measuring points, the coil group 2 has 7 position measuring coils L ₀ --L ₆ , 1 compensation coil Lc, and the position measuring coil is 2 Double control rod step lengths are arranged in order, and the compensation coil is placed outside the stroke of the control rod. The primary coil can be coaxially wound with the compensation coil and the positioning coil, or it can be wound separately at both ends of the compensation coil and each positioning coil, and the driving The shaft is designed according to the original code, the magnetic material is 1Crl3, and the non-magnetic material is 1Crl8Ni9Ti. According to the above, the first section of the drive shaft is a magnetic material, including 3 sections of magnetic material and 2 sections of non-magnetic material. The material lengths were 3, 7, and 11 times the control rod step length, respectively. The lengths of the non-magnetic materials are 7 and 3 times the step length of the control rods respectively. Do～D6 is the output waveform of the corresponding positioning coil, and the scale indicates 33 measuring points from 0-32. Table 1 is the truth table of the address codes of the 7 positioning coils, and Table 2 is the distribution table of the address codes of the 7 positioning coils.

Embodiment 2: This embodiment is designed according to the inverse code, the coil group 2, the magnetic material and the non-magnetic material are the same as the embodiment 1, and the first section of the drive shaft is a non-magnetic material, which contains a total of 3 sections of non-magnetic material and 2 sections of magnetically permeable materials, the lengths of non-magnetically permeable materials are 3, 7, and 11 times the step length of the control rods, and the lengths of the magnetically permeable materials are respectively 9 and 5 times the step length of the control rods. Table 3 shows 8 positioning coils Truth table, table 4 is the distribution table of 8 coil address codes.

The attached table is as follows: Table 1 is the truth table of the address codes of the 7 positioning coils.

Table 2 is the address code distribution table of 7 positioning coils.

Table 3 is the truth table of 8 coil address codes.

Table 4 is the address distribution table of 8 coils.

In the table: # indicates the stick address, and S indicates the pseudocode address.

Table 1 Truth table of 7 coil address codes stick position binary code hexadecimal code pseudocode 32313029282726252423222120191817161514131211109876543210 1 1 1 1 1 0 01 1 1 1 1 1 00 1 1 1 1 1 00 1 1 1 1 1 10 0 1 1 1 1 11 0 1 1 1 1 11 0 0 1 1 1 11 1 0 1 1 1 11 1 0 0 1 1 11 1 1 0 1 1 11 1 1 0 0 1 11 1 1 1 0 1 10 1 1 1 0 0 10 1 1 1 1 0 10 0 1 1 1 0 00 0 1 1 1 1 00 0 0 1 1 1 00 0 0 1 1 1 10 0 0 0 1 1 11 0 0 0 1 1 11 0 0 0 0 1 11 1 0 0 0 1 10 1 0 0 0 0 10 1 1 0 0 0 10 0 1 0 0 0 00 0 1 1 0 0 00 0 0 1 0 0 00 0 0 1 1 0 00 0 0 0 1 0 00 0 0 0 1 1 00 0 0 0 0 1 00 0 0 0 0 1 10 0 0 0 0 0 1 7C7E3E3F1F5F4F6F6777737B393D1C1E0E0F0747436321311018080C0406020301 3B, 791D, 3C23, 6111, 30

Table 1

Table 2 7 coil address code distribution table H/L 0 1 2 3 4 5 6 7 8 9 A B C D. E. f 01234567 #$ #$##$ # #$### # # #### ## #$ $# ##$# $# #### ######

Table 2

Table 3 Truth table of 8 coil address codes (inverse code) stick position binary code hex code pseudocode 38373635343332313029282726252423222120191817161514131211109876543210 0 0 0 0 0 1 1 10 0 0 0 0 0 1 11 0 0 0 0 0 1 11 0 0 0 0 0 0 11 1 0 0 0 0 0 11 1 0 0 0 0 0 01 1 1 0 0 0 0 00 1 1 0 0 0 0 00 1 1 1 0 0 0 00 0 1 1 0 0 0 00 0 1 1 1 0 0 00 0 0 1 1 0 0 00 0 0 1 1 1 0 00 0 0 0 1 1 0 01 0 0 0 1 1 1 01 0 0 0 0 1 1 01 1 0 0 0 1 1 11 1 0 0 0 0 1 11 1 1 0 0 0 1 11 1 1 0 0 0 0 11 1 1 1 0 0 0 11 1 1 1 0 0 0 01 1 1 1 1 0 0 00 1 1 1 1 0 0 00 1 1 1 1 1 0 00 0 1 1 1 1 0 01 0 1 1 1 1 1 01 0 0 1 1 1 1 01 1 0 1 1 1 1 11 1 0 0 1 1 1 11 1 1 0 1 1 1 11 1 1 0 0 1 1 11 1 1 1 0 1 1 11 1 1 1 0 0 1 11 1 1 1 1 0 1 11 1 1 1 1 0 0 11 1 1 1 1 1 0 11 1 1 1 1 1 0 01 1 1 1 1 1 1 0 07038381C1C0E060703038181C0C8E86C7C3E3E1F1F0F8787C3CBE9EDFCFEFE7F7F3FBF9FDFCFE 8C, 0EC6, 87BC, 3EDE, 9F

table 3

Table 4 8 coil address code distribution table (inverse code) H/L 0 1 2 3 4 5 6 7 8 9 A B C D. E. f 0123456789ABCDEF ###### #### ##### #$ #$### #### # # ####$$# # $$###$# $###

Table 4

Claims (1)

1, a kind of by stick location probe, the signal transmitting device, the address code measuring system for reactor control bar position that data processing unit and display screen are formed, above-mentioned stick location probe comprises coil groups and control rod driving shaft, coil groups comprises primary coil, compensating coil and N location coil, coil groups is installed in driving shaft tracks top, concentric with driving shaft, above-mentioned signal transmitting device comprises AC power, amplifying unit, rectification unit, comparing unit and switch level output unit, coil groups directly is connected with the signal transmitting device, the address signal of signal transmitting device output directly is connected with data processing unit with the coil fault signal, all is sent to display screen through later demonstration sign indicating number and other shows signal of data processing unit decoding, it is characterized in that:

(1) the location coil N in the above-mentioned coil groups is the positive integer greater than 5, and two adjacent location coil-spans are two times of step-lengths between the control rod measuring point;

(2) above-mentioned control rod driving shaft is alternately arranged by the permeability magnetic material of segmentation and non-magnet material and is processed, and M is the hop count that comprises the odd number section of first section material, M ₁Be the hop count that comprises the even number section of second section material, the relational expression of the hop count of permeability magnetic material and non-magnet material and location coil N is: when N is odd number, $M=\frac{1}{2}(N-1),$ When N is even number, $M=\frac{1}{2}(N-2);$ M ₁=M-1, the length of first section material is A, A is 3 times of control rod step-lengths, below with each segment length of first section same material be (A+4B) times control rod step-length, below with each segment length of first section same material be (A+4B) times control rod step-length, wherein B is since 1 sequence of natural numbers, and the length of second section material and later and second section same material satisfies relational expression [2 (N-2)-A-4 (B-1)] control rod step-length doubly;

(3) above-mentioned comparing unit adopts high level comparator and low-level comparator, and low-level comparator is exported excellent bit address signal, high level comparator output winding fault-signal, thus realize 2N switch level signal of N signal coil output.