CN112599255A

CN112599255A - Control rod drop reference signal generating device and method thereof

Info

Publication number: CN112599255A
Application number: CN202011417504.5A
Authority: CN
Inventors: 昌正科; 张明晖; 刘信信; 马一鸣; 欧明秋; 宫成军; 徐胜峰; 晁博; 李艺; 田野; 米正宇; 孟昊
Original assignee: Nuclear Power Operation Research Shanghai Co ltd
Current assignee: Nuclear Power Operation Research Shanghai Co ltd
Priority date: 2020-12-05
Filing date: 2020-12-05
Publication date: 2021-04-02
Anticipated expiration: 2040-12-05
Also published as: CN112599255B

Abstract

The invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method. The control rod drop reference signal generating device comprises a rod control power cabinet, a driving mechanism monitoring cabinet and a rod position measuring cabinet, wherein: the rod-controlled power supply cabinet comprises at least one Hall current sensor; the driving mechanism monitoring cabinet comprises a control rod drop reference signal generating module and at least one current-voltage conversion module; the rod position measuring cabinet comprises a control rod drop reference signal analysis module. The invention discloses a device and a method for generating control rod drop reference signals, which integrate dozens of drop time measurement reference signals required by common drop time measurement and analysis into a single reference signal and provide an analysis processing algorithm of the single reference signal.

Description

Control rod drop reference signal generating device and method thereof

Technical Field

The invention belongs to the technical field of nuclear power station control rod drop time measurement, and particularly relates to a control rod drop reference signal generating device and a control rod drop reference signal generating method.

Background

The fast regulation of reactor power in pressurized water reactor nuclear power plants is mainly achieved by controlling the lifting and downward insertion of the rod bundles. The lifting and inserting actions of the Rod cluster are driven by a set of electromagnetic Drive Mechanism (CRDM), referring to figure 1 of the attached drawings, when the Control Rod is static, a holding coil is electrified, and a holding hook (also called a clamping pin claw) swings into a tooth groove of a Drive shaft.

The emergency shutdown of the reactor is realized by opening a shutdown breaker, cutting off a CRDM power supply and allowing a control rod bundle to fall into a reactor core under the action of gravity. The length of the rod bundle dropping time is directly related to whether safe shutdown can be realized, and the rod dropping time is required to be smaller than a safe analysis value (typically 2.4 seconds in the second nuclear power plant in Qinshan), so the rod dropping time is measured before each pile starting.

The drop time consists of six segments, as shown in figures 2A and 2B of the accompanying drawings. Wherein,

t4-the time from the hold-in coil current dropping to 33% of nominal value to the start of the beam drop, should be <150 ms;

t5 — the time between the beginning of the bundle drop and the entry into the buffer segment;

t6-the time from when the cluster enters the buffer to when it reaches the bottom of the buffer, T4+ T5+ T6 should be less than 3s at hot.

The falling time of the control rods is influenced by the whole driving wire, the control rod driving wire is composed of a driving mechanism, a guide cylinder assembly, a fuel assembly, a control rod assembly and the like, the control rods possibly rub with the guide rods in the guide cylinder assembly and the fuel assembly in the falling process, and the buffer when the control rods fall is provided by a guide tube buffer section in the fuel assembly and a buffer spring below the control rod assembly. The buffer section length of a control rod guide tube in a typical power plant fuel assembly is 640mm, the length of a control rod entering the buffer section when falling to the bottom of a reactor is about 550-560mm, and 34.5 steps are carried out; the control rod assembly buffer spring has a total length of about 22.45mm and a maximum compression length of about 5mm when dropped.

Because the control rod and the connected driving shaft are positioned in the high-temperature and high-pressure environment of the nuclear reactor, the position of the control rod and the connected driving shaft is measured by a rod position detector by generally utilizing the electromagnetic induction principle, and the T4, T5 and T6 time periods can be measured only by utilizing the rod position detector in a non-contact way.

The typical rod position detector mainly comprises a primary coil, a measuring coil, an auxiliary coil, a coil framework, a sealing shell and an outer sleeve. Taking the second nuclear power plant in Qinshan as an example, the overall length of the rod position detector is 4006mm, the inner diameter is 154mm, and the outer diameter is 300 mm. The primary coil is a long solenoid, about 2000 turns, with a wire diameter of 1.97mm, and is wound along the entire stroke. The measuring coil and the auxiliary coil are secondary side coils, each of which has 1700 turns, 2cm width and 0.23mm wire diameter and is coaxial with the primary side coil. The primary coil is used for generating an alternating magnetic field, the measuring coil is used for forming a rod position code, and the auxiliary coil is used for primary current regulation.

The drive shaft is made of magnetic material, and the permeability of the sealing shell, the framework, the outer sleeve and other media in the detector is low, so that the voltage induced by the drive shaft passing through the measuring coil is greatly different, and the top end or the bottom end of the drive shaft can be known by monitoring the induced voltage of the measuring coil at a certain position. The position of the drive shaft, the control rod, can be determined substantially by monitoring the induced voltage signal of each coil, provided that a sufficient number of measurement coils are provided.

In order to substantially determine the position of the control rod, a sufficient number of measuring coils must be provided. The number and spacing of the measurement coils is determined based on the length of the drive shaft stroke and the desired resolution. In order to reduce the number of connections between the detectors and the signal processing channels, and the number of signal processing devices, the measurement coils must also be grouped.

Taking the second nuclear power plant in Qinshan as an example, the length of each mechanical step of the control rod driving shaft is 15.875mm, and the full stroke is 228 steps. The detector resolution was 8 steps (127mm), 31 measurement coils were divided into A, B, C, D, E five groups, and the total measurement stroke was 256 mechanical steps. The measurement coils are grouped as follows.

First, if a measuring coil C1 is wound at 1/2 of the measuring stroke of the probe, it is known whether the rod position is in the [0, 128 ] interval or the [128, 256 ] interval by monitoring the induced voltage (effective value, the same applies hereinafter) V1.

Further, if the coils C21 and C22 are wound at the heights of 1/4 and 3/4, the rod position can be known to be in a [0, 64) interval or a [64, 128) interval by monitoring the induced voltage V21 of the C21; by monitoring the induced voltage V22 of C22, it can be known whether the rod position is in the [128, 192) interval or the [192, 256) interval.

In fact, the three coils divide the whole measuring stroke into four intervals with equal length, and the induced voltage of the three coils is monitored to know which interval the rod position is in; the induced voltage levels and corresponding rod positions can be tabulated below.

If C21 and C22 are connected in series in reverse to form a group (called C2), because V21 and V22 are always in phase, the output voltage V2 of C2 is | V21-V22 |, and the induction voltage is low and the corresponding rod position is shown in the following table.

Similarly, four coils of C31, C32, C33 and C34 are wound at the heights of 1/8, 3/8, 5/8 and 7/8 and are sequentially connected in series in a positive-negative mode to form a C3 group, so that the whole measuring stroke can be divided into 8 intervals with equal length, and the interval in which the rod beam is located can be determined by monitoring three voltages of V1, V2 and V3 (i.e., | V31-V32 + V33-V34 |), and the measuring resolution reaches 32 steps.

And then eight coils C41, C42, … and C48 are wound at the heights of 1/16, 3/16, 5/16, 7/16, 9/16, 11/16, 13/16 and 15/16, and are connected in series in a positive-negative mode to form a C4 group, so that the whole measuring stroke can be divided into 16 intervals with equal length, and the interval in which the rod beam is located can be determined by monitoring four voltages V1, V2, V3 and V4 (i.e. | V41-V42 + V43 … -V48 |), and the measuring resolution reaches 16 steps.

And then sixteen coils C51, C52, … and C516 are wound at the heights of 1/32, 3/32, 5/32, … and 31/32 and are sequentially connected in series in a positive-negative mode to form a C5 group, so that the whole measuring stroke can be divided into 32 intervals with equal length, and the interval in which the rod bundle is positioned can be determined by monitoring five voltages V1, V2, V3, V4 and V5 (i.e. | V51-V52 + V53 … -V516 |), and the measuring resolution reaches 8 steps.

The C1, C2, C3, C4 and C5 groups are generally referred to as E, D, C, B, A groups, respectively, and the coils are numbered from low to high, so that the coils in each group are numbered as:

group E (first group) of coils 16

Group D (second group) coil 824

Group C (third group) coil 4122028

Group B (fourth group) coil 26101418222630

Group a (fifth group) coil 135791113151719212325272931

The detector structure and coil numbering refer to figure 3 of the drawings.

The length of the typical rod falling time T5 is about 1.5-2 seconds, and because the processing time of the normal rod position measurement signal is long, the rod falling time can not be obtained through the normal rod position measurement signal, and is generally obtained through measuring the induced voltage of the primary coil of the rod position detector. Referring to fig. 2A and 2B of the drawings, the rod-falling time is obtained by two parameters of the holding coil current and the primary coil induced voltage.

Conventionally, the rod drop time is measured by simultaneously connecting a current signal of a holding coil and an induced voltage signal of a primary coil led from a rod position device to a special recorder or a test cabinet, and the function of the led current signal of the holding coil is used as a reference signal of a T4 time calculation starting point. Because the number of control rods of the whole unit is large (33 bundles of control rods of a Qinshan second nuclear power plant, the number of control rods of a typical million kilowatt nuclear power unit is 61 bundles), the number of channels which are processed simultaneously when the special recorder or the test cabinet is adopted for measurement is limited originally, so the measurement is generally carried out in a grouping switching mode, after one subgroup is tested, a piezoelectric voltage signal switching cable of a primary coil is required to be taken down and connected to another rod group, a current signal switching cable of a holding coil is taken down and connected to another rod group, and the switching wiring work required during the test is large.

Disclosure of Invention

The present invention is directed to the state of the art, overcomes the above drawbacks, and provides a control rod drop reference signal generating device and a control rod drop reference signal generating method.

The invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method, and mainly aims to integrate dozens of drop time measurement reference signals (generally 61 million kilowatt nuclear power units) required by common drop time measurement and analysis into a single reference signal and provide an analysis processing algorithm of the single reference signal.

The invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method, and aims to create conditions for integrating a drop time measurement and analysis function into rod position measurement equipment, improve the automation level of drop time measurement and analysis and effectively reduce the nuclear reactor starting plan key path time occupied by the drop time measurement.

The invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method, and further aims to analyze drop reference signals in a rod position measuring cabinet.

The invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method, and further aims to effectively solve the problem of multi-signal switching.

The invention adopts the following technical scheme that the control rod drop reference signal generating device comprises a rod control power supply cabinet, a driving mechanism monitoring cabinet and a rod position measuring cabinet, wherein:

the rod-controlled power supply cabinet comprises at least one Hall current sensor;

the driving mechanism monitoring cabinet comprises a control rod drop reference signal generating module and at least one current-voltage conversion module;

the rod position measuring cabinet comprises a control rod drop reference signal analysis module;

the Hall current sensor positioned in the rod control power cabinet is used for collecting the current of the first rod bundle holding coil of each subgroup;

the current-voltage conversion module located in the drive mechanism monitoring cabinet converts each subset of first bundle retention coil currents to each subset of first bundle retention coil voltage signals;

the drive mechanism monitoring cabinet superimposes the voltage signals of the first rod cluster holding coils of each subgroup through a built-in adder circuit to form a comprehensive rod drop reference signal DROPref.

The invention further discloses a control rod drop reference signal generation method, the control rod drop reference signal generation device recorded in the technical scheme is adopted, and the following steps are executed:

step S1: monitoring the voltage of the group A coils and capturing rod falling signals;

step S2: obtaining a wand falling reference signal sequence during a period of backtracking from a wand falling starting point to 750 ms;

step S3: calculating the maximum and minimum values of the rod falling reference signal sequence;

step S4: backtracking from its minimum point to find the time point t33 where the amplitude is > minimum + 33% step amplitude;

step S5: backtracking from its minimum point to find the time point t80 where the amplitude is > minimum + 80% step amplitude;

step S6: the calculated T80 is taken as the starting point of the rod falling time T4.

According to the above technical solution, as a further preferable technical solution of the above technical solution, the step S2 is specifically implemented as the following steps:

step S2.1: recording the starting point of the falling rod as t 1;

step S2.2: obtaining t 0: if t1< ═ 750ms, then t0 equals 1, otherwise t0 equals t 1-750;

step S2.3: a time period sub-sequence of t0, t1 is taken from the droref signal sequence.

According to the above technical solution, as a further preferable technical solution of the above technical solution, the step S3 is specifically implemented as the following steps:

step S3.1: performing digital filtering processing on the DROPref signal subsequence obtained in the step 2;

step S3.2: the filtered subsequence is evaluated for a maximum Vmax, a minimum Vmin, and a minimum tmin index.

According to the above technical solution, as a further preferable technical solution of the above technical solution, the step S4 is specifically implemented as the following steps:

step S4.1: if Vmax + Vmin is less than 0.3, t33 has no effective value, otherwise, the following steps are continued;

step S4.2: t is tmin;

step S4.3: if the value of t time in the filtered DROPref signal subsequence is less than 33% Vmax, t is t-1;

step S4.4: if t < ═ 0 or the value Vt > at the time t of the DROPref signal subsequence is 33% Vmax, stopping;

step S4.5: if the cycle is stopped, Vt is less than 33% Vmax, then t33 has no effective value, otherwise t33 is t0+ t.

According to the above technical solution, as a further preferable technical solution of the above technical solution, the step S5 is specifically implemented as the following steps:

step S5.1: t is t33-t 0;

step S5.2: if the value of t time in the filtered DROPref signal subsequence is less than 80% Vmax, t is t-1;

step S5.3: if t < ═ 0 or the value Vt > at the time t in the DROPref signal subsequence is 80% Vmax, stopping;

step S5.4: if the cycle is stopped, Vt < 80% Vmax indicates that t80 has no valid value, otherwise t80 is t0+ t.

The device and the method for generating the control rod drop reference signal have the advantages that dozens of (61 in a million kilowatt nuclear power unit) drop time measurement reference signals required by common drop time measurement and analysis are integrated into a single reference signal, and an analysis processing algorithm of the single reference signal is provided.

Drawings

FIG. 1 is a schematic view of a control rod drive mechanism configuration.

FIG. 2A is a schematic diagram showing the composition of the rod drop time.

Wherein T4 is the time from the holding coil current dropping to 33% of nominal value to the beginning of the beam drop, which should be <150 ms; t5 — the time between the beginning of the bundle drop and the entry into the buffer segment; t6-the time from when the cluster enters the buffer to when it reaches the bottom of the buffer, T4+ T5+ T6 should be less than 3s at hot.

Fig. 2B is a schematic diagram of a drop profile feature point.

FIG. 3 is a schematic diagram of a rod position detector coil arrangement and connection.

FIG. 4 is a schematic diagram of the current dropping process for each bundle in the same subgroup.

Fig. 5 is a schematic view of a topology of a falling rod reference signal generating apparatus according to a preferred embodiment of the present invention.

Fig. 6A is a schematic diagram (in part) of a hall current sensor, a current collection device, in accordance with a preferred embodiment of the present invention.

Fig. 6B is a schematic diagram (in part) of a hall current sensor, a current collection device, in accordance with a preferred embodiment of the present invention.

Fig. 6C is a schematic diagram (in part) of a hall current sensor, a current collection device, in accordance with a preferred embodiment of the present invention.

Fig. 7 is a schematic diagram of a current-voltage conversion card according to a preferred embodiment of the invention.

FIG. 8A is a schematic diagram of a falling rod reference signal generation scheme in accordance with a preferred embodiment of the present invention.

FIG. 8B is a schematic diagram of the topology of the falling rod reference signal generation method according to the preferred embodiment of the present invention.

Wherein UO1 ═ U1+ U2+. + U16);

UO2＝-UO1*R5/R_3-18；

u1., 16 are voltage signals formed by converting the current of each subgroup holding coil respectively;

UO2 is the falling rod reference signal droprref.

Fig. 9 is a flow chart of finding the step time point of the falling rod reference signal according to the preferred embodiment of the invention.

FIG. 10A is a flow chart of a wand-fall signal capture algorithm.

Fig. 10B is a schematic illustration of a falling rod waveform.

Fig. 11 is a schematic diagram showing an example of the results of the calculation and analysis of the rod drop time.

Wherein, the analysis result is as follows: and (5) normally cutting off the power and dropping the rod.

With reference to the above figure, the results were normal by analysis of the Up induced voltage:

the reference signal is normal; t4 ═ 0.062 normal ═ 0.15, T5 ═ 1.2855 normal ═ 2.4, T5+ T6 ═ 1.778 normal ═ 3.2; the first bounce T7 is normal, the bounce time length T7 is normal, the second bottoming T8 is normal, and the second bounce T9 is normal.

Detailed data:

t0 ═ 20200309194540.313 dt ═ 0.0005; t4Bgn-440 (indicating that DROPref falls to 80% of the time);

t4Bgn 446 (stating: T4 begins: DROPref falls to 33% point in time);

t4End 564 (description: T4 End: 40% Vmax, 20% Vmax connecting line and cross axis intersection);

t5End 3135 (note: T5 End: 75% Vmax, 50% Vmax connection and Vmax horizontal intersection);

t6End 4120 (explaining that the intersection point of the connecting line of the point T6 which is first less than 0 after Vmax and the previous point thereof is T6 and the horizontal axis);

t7End 4337 (note: T7: point first >0 after T6);

t8End 4573 (note: point first < ═ 0 after T8: T7);

t9End 4750 (note: T9: point first >0 after T8);

t4+0.062 (Note: T4 stop-DROPref falls to 80% of time T4 Bgn-);

t40.059 (note: T4 stop-DROPref falls to 33% at time T4 Bgn);

t51.2855 (Explanation: T5 stop-T4 stop);

t60.4925 (Explanation: T6 stop-T5 stop);

t561.778 (Explanation: T5+ T6);

t70.1085 (Explanation: T7-T6);

t80.118 (Explanation: T8-T7);

t90.0885 (Explanation: T9-T8).

Detailed Description

The present invention discloses a control rod drop reference signal generating device and a control rod drop reference signal generating method, and the following describes the embodiments of the present invention with reference to the preferred embodiments.

Referring to figures 1 to 11 of the drawings, figure 1 shows a control rod drive mechanism configuration; FIG. 2A shows the composition of the drop time; FIG. 2B shows a drop bar waveform feature point; FIG. 3 illustrates a rod position detector coil arrangement and connection; FIG. 4 illustrates a same subgroup of individual bundle current drop processes; FIG. 5 illustrates the topology of the drop rod reference signal generating apparatus of the preferred embodiment of the present invention; FIG. 6A shows a current collection device-Hall current sensor (section) of a preferred embodiment of the present invention; FIG. 6B shows a current collection device-Hall current sensor (section) of a preferred embodiment of the present invention; FIG. 6C shows a current collection device-Hall current sensor (section) of a preferred embodiment of the present invention; FIG. 7 illustrates a current-to-voltage conversion card of a preferred embodiment of the present invention; FIG. 8A illustrates a falling rod reference signal generation in accordance with a preferred embodiment of the present invention; FIG. 8B illustrates a drop rod reference signal generation topology of a preferred embodiment of the present invention; FIG. 9 shows a flow of finding a step time point from a falling rod reference signal according to a preferred embodiment of the present invention; FIG. 10A shows a wand-drop signal capture algorithm flow; FIG. 10B illustrates a drop bar waveform; fig. 11 shows an example of the results of the calculation analysis of the rod drop time.

It is worth mentioning that conventionally, the measurement of the rod drop time is to connect the current signal of the holding coil and the induced voltage signal of the primary coil led from the rod position device to a special recorder or a test cabinet at the same time, and the function of the led current signal of the holding coil is used as a reference signal of the starting point of the T4 time calculation. Because the number of control rods of the whole unit is large (33 bundles of control rods of a Qinshan second nuclear power plant, the number of control rods of a typical million kilowatt nuclear power unit is 61 bundles), the number of channels which are processed simultaneously when the special recorder or the test cabinet is adopted for measurement is limited originally, so the measurement is generally carried out in a grouping switching mode, after one subgroup is tested, a piezoelectric voltage signal switching cable of a primary coil is required to be taken down and connected to another rod group, a current signal switching cable of a holding coil is taken down and connected to another rod group, and the switching wiring work required during the test is large.

In order to effectively solve the problem of multi-signal switching during the rod falling time measurement, the device and the method for generating the rod falling reference signal of the control panel integrate dozens of (generally 61 million kilowatt nuclear power units) rod falling time measurement reference signals required by the general rod falling time measurement analysis into a single reference signal, thereby reducing the number of the rod falling time measurement switching signals.

Preferred embodiments.

Preferably, referring to FIG. 9 of the drawings, the control rod drop reference signal generating method includes the steps of:

Further, referring to fig. 10A of the drawings, step S1 (monitoring a group a coil voltages, capturing a rod-drop signal) is embodied as the following steps:

step S1.1: carrying out digital filtering processing on the A group of coil voltages Ua;

step S1.2: folding the waveform and combining redundant endpoints;

step S1.3: calculating a median sequence;

step S1.4: finding the first minimum point P2, tmin and Vmin of the median sequence;

step S1.5: backtracking from the first minimum point to find the median point P1 < Vmin/2;

step S1.6: finding the intersection point P0 of the minimum point P2, the median point P1 and the 0 axis;

step S1.7: if the slope, the time difference and the amplitude difference of the connecting lines P0 and P2 are in a specific range, the rod falling is judged to be started.

Further, the step S2 (finding the wand-falling reference signal sequence during the backtracking from the wand-falling start point to 750 ms) is specifically implemented as the following steps:

step S2.1: recording the starting point of the falling rod as t 1;

Further, step S3 (calculating the maximum and minimum values of the falling rod reference signal sequence) is implemented as the following steps:

Further, step S4 (tracing back from its minimum point to find the time point t33 where the amplitude > minimum + 33% step amplitude) is embodied as the following steps:

step S4.2: t is tmin;

Further, step S5 (tracing back from its minimum point to find the time point t80 where the amplitude > minimum + 80% step amplitude) is embodied as the following steps:

step S5.1: t is t33-t 0;

It is worth mentioning that the falling rod reference signal is used for the example of the calculation and analysis result of the falling rod time, see fig. 11 of the drawings, wherein T4 Bgn-corresponds to the time point T80 when the droref falls to 80%, and T4Bgn corresponds to the time point T33 when the droref falls to 33%.

A first embodiment.

Preferably, referring to fig. 5 of the drawings, the control rod drop reference signal generating apparatus comprises a rod control power supply cabinet 10, a drive mechanism monitoring cabinet 20 and a rod position measuring cabinet 30, wherein:

the rod-controlled power supply cabinet 10 comprises at least one Hall current sensor 11;

the drive mechanism monitoring cabinet 20 comprises a control rod drop reference signal generating module 22 and at least one current-voltage converting module 21;

the rod position measurement cabinet 30 includes a control rod drop reference signal analysis module 31.

Referring to fig. 4 of the drawings, the power supply cut-off time of each cluster in the same subgroup is the same based on the measurement of the rod drop time, the current drop curves are basically synchronous, the time point when the current of any cluster drops to 80% is earlier than the time point when the current of other clusters drops to 33%, so that the time point when the current of a certain cluster drops to 80% is only slightly longer than the time point of T4 as the time starting point of the drop time of all the clusters in the same subgroup T4, and the determination of the rod drop time is conservative.

Referring to fig. 6 of the drawings, the hall current sensors 11 located in the bar-controlled power cabinet 10 are used to collect the first bundle-holding-coil currents of the respective sub-groups.

Referring to fig. 7 of the drawings, the current-voltage conversion module 21 located in the drive mechanism monitoring cabinet 20 converts each subset of first bundle retention coil currents to each subset of first bundle retention coil voltage signals;

referring to fig. 8A and 8B of the drawings, the drive mechanism monitor cabinet 20 superimposes the first rod cluster holder coil voltage signals of each subset through a built-in adder circuit to form a composite drop rod reference signal droprref.

When the rod drop time of the control rods is measured, an operator of the reactor in the main control room respectively lifts each group of control rods, after the control rods are lifted to the top of the reactor, a corresponding power supply subgroup is disconnected in the rod control power distribution cabinet, and a power supply disconnection signal is transmitted to the rod position measuring cabinet 30 through a rod drop reference signal DROPref.

When any subgroup of power supplies are disconnected, the DROPref signal generates a step change, time points T80 and T33 when the DROPref step drops to 80 percent and 33 percent are identified in the rod position measuring cabinet 30, a T80 is used as a rod drop time calculation starting point, the obtained measuring result is about 5ms earlier than the position where the actual current of each rod bundle drops to 33 percent, and the deviation is conservative and can be used for judging the rod drop time T4<150 ms; t33 is used as the reference value for the degree of advance of decision t 80.

The control rod drop reference signal generating device and the method thereof disclosed by the embodiments of the invention have the following control basis of the main working principle.

The invention provides a rod drop time reference signal generating device and a method thereof, aiming at effectively solving the problem of multi-signal switching during rod drop time measurement, creating conditions for integrating a rod drop time measurement and analysis function into rod position measurement equipment, improving the automation level of rod drop time measurement and analysis, and effectively reducing the nuclear reactor startup plan key path time occupied by rod drop time measurement.

Specifically, referring to fig. 4 of the drawings, in the method, based on the measurement of the rod drop time, the power supply cut-off time of each rod bundle in the same subgroup is the same, the current drop curves are basically synchronous, the time point when the current of any rod bundle drops to 80% is earlier than the time point when the current of other rod bundles drops to 33%, so that the time point when the current of a certain rod bundle drops to 80% is only slightly longer than the time point of T4 as the time starting point of T4 of all rod bundles in the same subgroup, and the rod drop time is conservative.

The main working principle of the control rod drop reference signal generating device and the method disclosed by the embodiments of the invention is explained as follows.

Specifically, when the method is used for measuring the rod falling time, a rod falling reference signal is transmitted to the rod position measuring cabinet through the pair of core wires, so that a starting point signal can be provided for calculation and analysis of the rod falling time of all rod bundles, the problem of multi-signal switching is effectively solved, the automation level of measurement and analysis of the rod falling time is improved, and the critical path time of a nuclear reactor starting plan occupied by the measurement of the rod falling time is effectively reduced.

It should be noted that the technical features such as specific selection of the control rod and the like related to the present patent application should be regarded as the prior art, the specific structure and the operation principle of the technical features and the control mode and the spatial arrangement mode which may be related to the technical features should be adopted by the conventional selection in the field, and should not be regarded as the invention point of the present patent, and the present patent is not further specifically described in detail.

It will be apparent to those skilled in the art that modifications and equivalents may be made in the embodiments and/or portions thereof without departing from the spirit and scope of the present invention.

Claims

1. A control rod drop reference signal generating device is characterized by comprising a rod control power supply cabinet, a driving mechanism monitoring cabinet and a rod position measuring cabinet, wherein:

2. A control rod drop reference signal generating method, characterized in that the control rod drop reference signal generating apparatus as set forth in claim 1 is used to perform the following steps:

3. The control rod drop reference signal generation method as set forth in claim 2, wherein the step S1 is embodied as the steps of:

step S1.2: folding the waveform and combining redundant endpoints;

step S1.3: calculating a median sequence;

4. The control rod drop reference signal generation method as set forth in any one of claims 2 to 3, wherein the step S2 is embodied as the steps of:

step S2.1: recording the starting point of the falling rod as t 1;

5. The control rod drop reference signal generation method as set forth in claim 4, wherein step S3 is embodied as the steps of:

6. The control rod drop reference signal generation method as set forth in claim 5, wherein step S4 is embodied as the steps of:

step S4.2: t is tmin;

7. The control rod drop reference signal generation method as set forth in claim 6, wherein the step S5 is embodied as the steps of:

step S5.1: t is t33-t 0;