CN112599255B

CN112599255B - Control rod drop reference signal generating device and method thereof

Info

Publication number: CN112599255B
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: 2023-02-10
Anticipated expiration: 2040-12-05
Also published as: CN112599255A

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 bundle 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 Drive shaft tooth groove.

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 the content of the first and second substances,

t4= the time from the holding coil current dropping to 33% of nominal value to the start of the rod bundle drop, should be <150 ms;

t5= the time from the beginning of the bundle descent to the entry into the buffer section;

t6= the time from the entry of the bundle into the buffer section to its arrival at the bottom of the buffer section, T4+ T5+ T6 should be less than 3s at the hot state.

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 the control rod falls 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 300mm. The primary coil is a long solenoid, about 2000 turns, 1.97mm in wire diameter, and is wound along the whole 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 resolution of the detector is 8 steps (127 mm), 31 measuring coils are divided into five groups of A, B, C, D and E, and the whole measuring stroke is 256 mechanical steps. The measurement coils are grouped as follows.

First, if a measuring coil C1 is wound at 1/2 of the height 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, hereinafter the same as) V1.

Further, if the coils C21 and C22 are wound at 1/4 and 3/4 of the height, whether the rod position is in the [0, 64) interval or the [64, 128) interval can be known by monitoring the induced voltage V21 of the coil 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 C2 output voltage V2= | V21-V22|, the induction voltage is high or 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 height of 1/8, 3/8, 5/8 and 7/8 and are sequentially connected in series in a positive and negative way to form a group C3, so that the whole measuring stroke can be divided into 8 sections with equal length, and the section in which the rod beam is positioned can be determined by monitoring three voltages V1, V2 and V3 (= | V31-V32+ V33-V34 |), and the measuring resolution reaches 32 steps.

And then winding eight coils of C41, C42, 8230and C48 at the heights of 1/16, 3/16, 5/16, 7/16, 9/16, 11/16, 13/16 and 15/16, and sequentially connecting the eight coils in series in a positive and negative way 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 positioned can be determined by monitoring four voltages of V1, V2, V3 and V4 (= | V41-V42+ V43 8230; -V48 |), and the measuring resolution reaches 16 steps.

And then winding C51, C52, 8230and C516 sixteen coils at the height of 1/32, 3/32, 5/32, 8230, and 31/32, and sequentially connecting the coils in series in a positive and negative way 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 beam is positioned can be determined by monitoring five voltages V1, V2, V3, V4 and V5 (= | V51-V52+ V53 \823030; V516 |), and the measuring resolution reaches 8 steps.

The C1, C2, C3, C4, 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 groups are numbered as:

group E (first group) of coils 16

Group D (second group) of coils 8 24

Group C (third group) coils 412 20 28

Group B (fourth group) of coils 26 10 14 18 26 30

Group a (fifth group) coil 135 7 9 13 15 17 19 21 23 25 27 29 31

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 longer, the rod falling time cannot be obtained through the normal rod position measurement signal, and is generally obtained through measuring the induced voltage of a primary coil of a 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 second nuclear power plant in Qinshan mountain, and 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 a special recorder or a testing cabinet is adopted for measurement is limited, so the measurement is generally carried out in a grouping switching mode, after one subgroup is tested, a primary coil piezoelectric voltage signal transfer cable is required to be taken down and connected to another group, a holding coil current signal transfer cable is taken down and connected to another 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, and provides a control rod drop reference signal generating apparatus and a control rod drop reference signal generating method.

The invention discloses a device and a method for generating control rod drop reference signals, which mainly aim to integrate dozens of (61 generally million kilowatt nuclear power units) drop time measurement reference signals required by the measurement and analysis of the common drop time 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 critical path time of a nuclear reactor start plan 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 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 cluster 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 generating method, and the control rod drop reference signal generating device recorded in the technical scheme is adopted to execute the following steps:

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

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

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

and step S4: backtracking from the minimum point to find the time point t33 with the amplitude larger than the minimum value and the step amplitude of 33 percent;

step S5: backtracking from the minimum point to find the time point t80 with the amplitude larger than the minimum value plus 80% step amplitude;

step S6: and taking the calculated T80 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 initial point of the rod falling as t1;

step S2.2: obtaining a t0: t0=1 if t1< =750ms, otherwise t0= t1-750;

step S2.3: a t0, t1 time period subsequence is taken from the DROPref 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 maximum Vmax, minimum Vmin, and subscript tmin to obtain the minimum are found for the filtered subsequence.

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 = tmin;

step S4.3: t = t-1 if the value at time t in the filtered DROPref signal subsequence is <33% Vmax;

step S4.4: aborting if t < =0 or the time t value Vt > =33% vmax in the DROPref signal subsequence;

step S4.5: t33 has no effective value if Vt <33% vmax at the time of cycle termination, otherwise t33= 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: setting t = t33-t0;

step S5.2: t = t-1 if the value at time t in the filtered DROPref signal subsequence is <80% > -vmax;

step S5.3: aborting if t < =0 or the time t value Vt > =80% in the DROPref signal subsequence, vmax;

step S5.4: t80 has no significant value if Vt <80% vmax at the time of loop termination, otherwise t80= 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 of a control rod drive mechanism configuration.

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

Where T4= the time from the holding coil current dropping to 33% of nominal value to the start of the beam drop, should be <150 ms; t5= time between the beginning of the rod bundle drop and the entry into the buffer segment; t6= the time from when the bundle enters the buffer section to when it reaches the bottom of the buffer section, T4+ T5+ T6 should be less than 3s in the hot state.

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 preferred embodiment of the present invention showing the manner in which a wand drop reference signal is generated.

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 respectively converting the current of each subgroup of holding coils to form voltage signals;

UO2 is the falling rod reference signal DROPref.

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

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

Fig. 10B is a schematic view of a wand drop 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 normally < =0.15, T5=1.2855 normally < =2.4, T5+ T6=1.778 normally < =3.2; the first bounce T7 is normal, the bounce duration T7 is normal, the second bottoming T8 is normal, and the second bounce T9 is normal.

Detailed data:

t0=20200309 194540.313dt =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 (note: T4 End: 40%: vmax, 20%; vmax connecting line and horizontal axis intersection);

t5End 3135 (description: T5 End: 75% Vmax, 50% Vmax line-Vmax horizontal line intersection point);

t6End 4120 (explaining that the intersection point of the connecting line between the point T6 which is first less than 0 after the T6End is Vmax and the previous point thereof and the horizontal axis);

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

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

t9End 4750 (illustrating the point where T9: T8 is first > 0);

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

t4 0.059 (which shows that T4 stops and DROPref falls to 33% of the time point T4 Bgn);

t5.2855 (note: T5 stop-T4 stop);

t6.4925 (Note: T6 stop-T5 stop);

t56.778 (Explanation: T5+ T6);

t7.1085 (description: T7-T6);

t8.118 (note: T8-T7);

t9 0.0885 (Explanation: T9-T8).

Detailed Description

The present invention discloses a control rod drop reference signal generating apparatus 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 shows 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 the preferred embodiment of the 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 the 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:

and step S4: backtracking the time point t33 with the search amplitude value being larger than the minimum value and the step amplitude being 33% from the minimum value point;

Further, referring to fig. 10A of the drawings, step S1 (monitoring a group a coil voltage, 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: the waveform is broken into lines and redundant end points are merged;

step S1.3: calculating a median sequence;

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

step S1.5: backtracking and searching a median point P1 of < Vmin/2 from the first minimum point;

step S1.6: solving 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 of P0 and P2 are in a specific range, the rod falling is judged to be started.

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

step S2.1: recording the initial point of the rod falling as t1;

step S2.2: obtaining a t0: t0=1 if t1< =750ms, otherwise t0= t1-750;

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

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

Further, step S4 (finding the time point t33 with the amplitude > minimum +33% step amplitude back from its minimum value point) is embodied as the following steps:

step S4.2: t = 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 = t33-t0;

step S5.2: t = t-1 if the value at time t in the filtered DROPref signal subsequence is < 80%;

It is worth mentioning that the bar falling reference signal is used for bar falling time calculation analysis results as an example, see fig. 11 of the drawings, where T4 Bgn-corresponds to T80 when DROPref falls to 80%, and T4Bgn corresponds to T33 when DROPref 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 conversion module 21;

the rod position measuring 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 taken as the time starting point of the T4 time of all the clusters in the same subgroup, the T4 time is only slightly prolonged, and the judgment 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-to-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 monitoring cabinet 20 superimposes the first rod cluster holding coil voltage signals of each subset through a built-in adder circuit to form a composite drop rod reference signal droprf.

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 decreases to 80 percent and 33 percent are identified in the rod position measuring cabinet 30, the T80 is used as a rod falling time calculation starting point, the obtained measuring result is about 5ms ahead of the position where the actual current of each rod bundle decreases to 33 percent, and the deviation is conservative and can be used for judging the rod falling time T4<150 ms; t33 is used as the reference value for determining t80 advance.

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

In order to effectively solve the problem of multi-signal switching during the rod-falling time measurement, the invention provides a rod-falling reference signal generating device and a method thereof, which create conditions for integrating the rod-falling time measurement and analysis function into a rod position measuring device, improve the automation level of the rod-falling time measurement and analysis, and effectively reduce the nuclear reactor startup plan key path time occupied by the rod-falling 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 taken as the time starting point of the T4 time of all the rod bundles in the same subgroup, the T4 time is only slightly lengthened, and the judgment of 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.

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 control rods related to the present patent application should be regarded as the prior art, and the specific structure, operation principle, and control manner and spatial arrangement manner that may be related to these technical features may be conventional in the art, 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:

said current-to-voltage conversion module at said drive mechanism monitoring cabinet converting each subset of first bundle retention coil currents to each subset of first bundle retention coil voltage signals;

2. A control rod drop reference signal generating method, characterized by employing the control rod drop reference signal generating apparatus as set forth in claim 1, and performing the steps of:

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

step S1 is specifically implemented as the following steps:

step S1.3: calculating a median sequence;

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

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

step S1.7: if the slope of the connecting line of the P0 and the P2, the time difference and the amplitude difference are in a specific range, judging that the rod is dropped;

step S2: obtaining a rod falling reference signal sequence during tracing back 750ms from a rod falling starting point;

step S2 is specifically implemented as the following steps:

step S2.1: recording the starting point of the rod as t1;

step S2.2: obtaining t0: t0=1 if t1< =750ms, otherwise t0= t1-750;

step S2.3: taking a t0, t1 time period subsequence from the DROPref signal sequence;

step S3 is specifically implemented as the following steps:

step S3.2: solving the maximum Vmax, the minimum Vmin and the subscript tmin for obtaining the minimum of the filtered subsequence;

step S4 is specifically implemented as the following steps:

step S4.2: t = tmin;

step S4.4: stopping if t < =0 or the t-time value Vt > =33% vmax in the DROPref signal subsequence;

step S4.5: t33 has no significant value if Vt <33% vmax at the time of cycle termination, otherwise t33= t0+ t;

step S5 is specifically implemented as the following steps:

step S5.1: t = t33-t0;

step S5.4: t80 has no significant value if Vt <80% vmax at the time of cycle termination, otherwise t80= t0+ t;