JPH02157697A - Remaining life diagnostic device for control rod driving mechanism - Google Patents

Abstract

PURPOSE:To find the remaining life time of a CRD with high accuracy by performing CRD inclination analytic processing based upon information in a 1st data base part and CRD reliability analytic processing based upon information in a 2nd data base part. CONSTITUTION:A remaining life comparison processing system by a main diagnostic device compares the remaining life diagnostic result and reliability analytic remaining life diagnostic result of an inclination analytic subsystem (F32). Then, the minimum remaining life time corresponding to a specified CRD manufacture number of a specified real plant is calculated (F33) and outputted (F34). On the other hand, scrum time data corresponding each constant inspection degree are plotted for a plate name, a test item example, and a manufacture number which are specified and data up to 5th inspection are plotted after disassembling inspection to calculate and display the estimated inspection degree of arrival to a control target value as TSC. Here, TX is the time in remaining life diagnosis and the remaining life time (period) of the CRD is estimated as TSC-TX.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control rod drive mechanism remaining life diagnosis device, particularly a control rod drive mechanism that diagnoses the remaining life from trend analysis results and reliability analysis results. Relating to a remaining life diagnosis device.

[Prior art] A conventional example of managing the lifespan of general equipment and parts is JP-A No. 62-276470 "Lifespan management device for equipment and parts".
There is.

This conventional example searches for information on past malfunctions and failures of equipment and parts, performs reliability analysis, and estimates average lifespan, failure rate, and failure mode. Furthermore, trend management and reliability analysis of equipment and parts each independently estimate the remaining life.

[Problems to be Solved by the Invention] The above-mentioned conventional example relates to life management of general equipment and parts. However, the control rod drive mechanism of a nuclear reactor (
In the case of CRD), there have been almost no failures or failures in the past, and reliability analysis should rather be performed using accelerated test data, and it is necessary to estimate the remaining life based on this.

Further, it is necessary to comprehensively compare and process remaining life diagnosis methods such as trend management and reliability analysis for one device (CRD), but the conventional example does not have such a viewpoint.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control rod drive mechanism remaining life diagnosis device that estimates the remaining life of a CRD with high accuracy.

[Means for Solving the Problems] The present invention includes a reliability analysis database unit that includes information obtained from accelerated tests of CRD, a trend analysis database unit that stores trend information, and a reliability analysis database unit that stores information for trend analysis. A comparison of the method for determining the remaining life for reliability using the information in the data section, the method for determining the remaining life for the trend using the information in the database section for trend analysis, and the remaining life for reliability and the remaining life for trend. and a means for estimating the remaining life of the CRD.

[Operation] According to the present invention, the remaining life of the CRD is estimated by determining the remaining life for trends and the remaining life for reliability and comparing the two.

[Example] FIG. 1 is a diagram showing an example of the remaining life diagnosis device of the present invention. In this example, various information for trends (plant name information 1, CR
D equipment information 2, CRD function test information 3, remaining life diagnosis management target value information 4), various information for reliability (CRD accelerated test information 5, remaining life diagnosis limit value information 6, Weibull distribution analysis information 7) Each of these pieces of information is latched into the trend analysis database section 10 through the input devices 8 and 9, and the latter is latched into the reliability analysis database section 12 to form a database.

The central processing unit 11 includes a control device 11A and a main memory 11B.
, an arithmetic unit 11G. The control device 11A performs control and management, and performs various processing using the main memory IIB and the arithmetic unit @11C.

The print output device 13 prints the output of the device 1l11, CR
1 display device 14 displays the output of device 11.

The auxiliary memory 15 stores various program sections 16A and 16B.
, 16C, 16D. The program section 16A is C.
It is a trend analysis subsystem having an RD trend analysis program, the program part 16B is a remaining life comparison diagnosis system having a remaining life comparison diagnosis program, and the program part 16C is a reliability analysis subsystem having a CRD reliability analysis program. The program section 16D is a remaining life diagnosis expert system.

Now, when the remaining life diagnosis expert system 16D is activated, each subsystem and its operating program stored in the auxiliary memory 15 are sent to the main memory 11B, and predetermined processing is performed. If it is program part 16A, CRD
CRD trend analysis is performed based on the trend analysis database unit 10. The program section 16C performs CRD reliability analysis using the CRD reliability analysis database section 2. For program section 16B, 16A and 1
Compare the remaining life determined with 6G.

2 to 5 show the processing flow of each program section 16A to 16G. In particular, FIG. 2 shows the processing of the program section 16A, FIGS. 3 and 4 show the processing of the program section 16C, and FIG. 5 shows the processing of the program section 16C. The processing of the program section 16B is shown.

The process shown in FIG. 2 will be explained. First, when the trend analysis subsystem is selected, the name of the plant for which the remaining life of the CRD is to be diagnosed is specified (F1 to F3).

Next, CRD diagnoses the remaining life of the specified plant name.
Serial number (The serial number is the unique name of the CRD.)
and designate test items for which trend analysis is to be performed from among a plurality of functional tests (F3 to F5).

Input the remaining life management target value for the test item specified here (F6) (If the management target value has already been input as an initial value for each test item, this operation is not necessary.

).

The system reads data up to the point where the diagnosis was made for the specified plant, CRD serial number, and test item (F7).

The arithmetic unit 11C calculates whether the data up to the current point has reached the remaining life management target value, and if it has reached the management target value, outputs an instruction to carry out inspection of the specified CRD (F8. FIO). .

If the control target value has not been reached, fit the test item data up to the current point (F8°F9) (The fitting method is the least squares method, which is frequently used statistically, but other fitting methods may be used as necessary. ).

The time required for the fitting line to reach the management target value is calculated by the arithmetic unit 11C and displayed on the CRT (Fll).

Perform the above procedure for all test items (F12),
The time required to reach the management target value with the minimum remaining life for the test items trend-analyzed so far is calculated by the computer (F13), and the inspection timing for the specified CRD serial number is output and displayed on the CRT screen (F14). ).

Next, the operation of the reliability analysis subsystem will be explained with reference to FIGS. 3 and 4.

In Figure 3, the reliability analysis subsystem (F15) specifies the parts that are subject to accelerated testing of the parts that make up the CRD (F16), and specifies the accelerated test item parameters (F17) (generally the remaining life of the CRD). The typical component that determines C
The accelerated test target parts and accelerated test item parameters for diagnosing the remaining life of the RD will be explained using the bending strength of a carbon seal as a representative example. ).

Next, from among the CRD acceleration tests performed on multiple CRDs, the CRD number (opinion of the number of the CRD attached to the acceleration test equipment, not the actual plant) for diagnosing the remaining life is specified (F18).

Here, for the specified accelerated test target part (here, carbon seal), CRD number, and test item parameter (here, bending strength), each severe condition (in the case of carbon seal, it deteriorates due to changes in temperature conditions - high temperature). Since the speed progresses rapidly, data will be taken hereafter as a representative example of temperature as a parameter of severe conditions.) Data is read in (F19).

Next, the read data is plotted and the deterioration tendency is displayed on the screen (F20). Also, input the limit value of the accelerated test item parameter (bending strength) (F21) (If the limit value has already been input as the initial value, 1 water damage operation is not necessary.

).

Here, the computer calculates the time required to reach the limit value under each harsh environmental condition (temperature condition) (F22), plots each time data, and fits the plot points (the fitting method is similar to trend analysis, with a minimum of 2 The time required to reach the limit value under normal operating environment conditions of the CRD (this time can be thought of as the failure time of the CRD) is calculated and displayed on the screen on the CRT.
F23).

The above procedure is carried out on a plurality of CRDs tested (F24), and the time to reach the limit value (CRD failure time) under normal operating environment conditions of the CRD is calculated as a plurality of sample data and displayed on the screen on the CRT.

Next, the operation shown in FIG. 4 will be explained. Perform Weibull distribution reliability analysis based on the time to reach the limit value (CRD failure time) of all CRDs subjected to accelerated testing (F25) (Weibull distribution is generally used for failure life and reliability analysis of nine equipment parts. (This is a statistical method that is widely used in

Number of CRD accelerated test data, number of failures, number remaining.

Estimate the Weibull distribution by unreliability (1-reliability),
Calculate the shape parameter m (m is a parameter that serves as an index for classifying nine equipment parts into three failure patterns: initial failure, random failure, and wear-out failure), estimate the failure pattern, and display it on the CRT screen. Let (F
26).

Next, calculate the time-reliability curve according to the failure pattern of the shape parameter m.
In other words, the average life time, average failure rate (average failure rate is the reciprocal of the average failure life), and reliability of the CRD are calculated and displayed on the CRT (F28, F29).

Here, the mean time between failures (the time obtained by dividing the sum of the time to reach the remaining life limit value under normal operating environment conditions in multiple CRD accelerated tests by the number of accelerated test data), that is, the average remaining life time of the CRD, is calculated as follows: The result is the average failure time. Therefore, by adjusting the reliability at this time, in order to derive a more reliable CRD remaining life, input the allowable reliability as necessary and calculate the CRD remaining life time at the allowable reliability. It is also possible to display it on the screen (F29A, F30°F3
1).

The remaining life comparison process shown in FIG. 5 will be explained. In FIG. 5, first, the remaining life diagnosis results of the above trend analysis subsystem and the reliability analysis remaining life diagnosis results are compared (F32).

Next, calculate the minimum remaining life time for the specified CRD serial number in the specified actual plant (F33), and output (
F34).

FIG. 6, FIG. 7, and FIG. 8 are examples of CRD trend analysis function test display screens.

Figure 6 shows examples of designated plant names and test items.

The scram time data for each periodic inspection order is plotted against the serial number, and the data from the 1st overhaul to the 5th periodic inspection is fitted (using the method of least squares).
The expected regular check order to reach the management target value is calculated and displayed as Tsc. Tx is the time at the time of remaining life diagnosis, and C
The remaining life time (period) of the RD is estimated as TSC-Tx.

Figures 7 and 8 show the normal driving time, stall flow (the amount of leakage of CRD drive water caused by deterioration of the carbon seal, and the unit is generally +27w1n, or rd/h).
This is an example of plotting (e.g. r, etc.). CR using the same procedure as in Figure 6
The remaining life time (period) of D can be estimated. In the example of constant drive time in FIG. 7, TMo-T.

In the stall flow example of FIG. 8, T ST −T x
becomes.

FIG. 9 is an example of a CRD trend analysis function test remaining life comparison display screen. According to Fig. 9, for the specified plant name and serial number, the minimum remaining life time (TLI) is determined from the expected regular test order to reach the control target value for all functional test items.
Here, TLI = TST TX) is calculated and displayed.

FIG. 10 is an example of a CRD reliability analysis accelerated test curve display screen (CRD-1), and FIG. 11 is an example of a CRD reliability analysis accelerated test curve display screen (CRD-&1).

Figure 1O is a curve showing the temperature effect on the bending strength, which is an accelerated test parameter, of carbon seals for accelerated test CRD (Nα1).
, N + B'C, N10'C (N is the normal operating environment condition) and the bending strength when the temperature is higher than the normal operating condition are plotted and fitted, and the time at which the limit value is reached is T^ Calculated and displayed as 1°TBI + 'rat.

Figure 11 is a screen in which the time at normal operating temperature N'C is estimated by plotting and fitting the time to reach the limit value under each temperature condition calculated in Figure 10, and the acceleration test CRD number. The life time (time to failure, ie failure time) of Storm 1 is estimated to be TNI.

Figures 12, 13, 14, and 15 are CRD-
Nα2. CRD-Nα3 life time (failure time) TN2
In a display example in which 1TN3 is similarly estimated, a plurality of these acceleration test data are sampled and Weibull distribution analysis is performed.

FIG. 16 is an example of a Weibull distribution plot data display screen, FIG. 17 is an example of a Weibull distribution analysis result display screen, and FIG. 18 is an example of a remaining life diagnosis reliability analysis display screen.

Figure 16 shows the life time (failure time) and number of failures estimated in Figures 10 to 15 (here, complete data is collected only for samples in which all data for which accelerated tests have reached the limit value). This is an example in which the reliability estimate and the unreliability estimate are calculated from the remaining number and displayed on the screen.

FIG. 17 shows the failure time T Nl e T according to FIG.
This is an example in which the slope m of the fitting line is calculated and displayed by plotting the estimated unreliability values of N2 to TNk and performing fitting.

m refers to the failure of one component of equipment as an initial failure or an accidental failure.

The parameter is an indicator for classifying wear-out failures into three failure patterns. 1m×1 is a decreasing failure rate type and is an early failure area, m=1 is a constant failure rate type and is an accidental failure area, and m)l is an increasing failure rate. The mold is said to be in the wear-out failure area.

In FIG. 17, as a simple example of Weibull distribution analysis, it is assumed that the analysis result is obtained when the slope m of the fitting line is 1, that is, the failure rate is constant and is in the random failure region.

In this case, time (1) and reliability R(t) have an exponential distribution relationship.

FIG. 18 shows the reliability curve estimated as a constant failure rate exponential distribution with m=1 in FIG. 17, and is R(t)=exp(-λ
It is expressed by the relational expression t). (R(t) is the reliability, λ
is the average failure rate) o m > 1 t m <
1 reliability curve is shown for reference.

T8 is the time at the time of diagnosis, and the reliability at that time is R.

T is the mean time between failures (M T B F : Mean
time between failure) is the time obtained by dividing the sum of the failure times TNI""TNk by the number of data, and is the average life time of the CRD. Therefore, C.R.D.
The average remaining life time is estimated to be Te-T.

Furthermore, in order to derive a more reliable remaining life of the CRD, if the allowable reliability RP is set, the CRD remaining life time (TL2) at the allowable reliability RP is T.

-Tx is estimated.

FIG. 18 is an example of calculating and displaying the CRD remaining life time and CRD average remaining life time at the allowable reliability.

Figure 19 is an example of the remaining life diagnosis analysis result display screen, showing the remaining life time (TLI = TST) calculated by trend analysis.
TX) and remaining life time (T
L2=TP-TX), and calculate the specified CRD serial number (001) in the specified actual plant (F plant).
The present invention is achieved by outputting the remaining life time of the CRD and displaying the recommended periodic inspection time for the next inspection of the CRD.

According to this example, the number of inspections during CRD disassembly and inspection, which used to be a critical pass process during periodic inspections of nuclear power plants, has been streamlined, and this has a significant effect on shortening the process during periodic inspections, reducing the amount of work, and reducing radiation exposure. There is.

In particular, 1100 MWe class boiling water nuclear power plants (hereinafter referred to as B
There are 185 CRDs installed in the WR (referred to as WR), and currently, the CRDs are inspected every 5 years (this inspection cycle is not based on any particular basis and is based on maintenance). As a result, approximately 37 inspections were carried out, resulting in a criticality pass process of approximately 12 days (as inspections were carried out for 3 inspections per day).

According to the present invention, it is possible to reasonably calculate and estimate the remaining life of the CRD, and it is thought that the number of CRDs inspected during one periodic inspection will be approximately 50%.

Therefore, it is thought that the amount of work and the amount of radiation exposure in the CRD critical pass process 2 during regular inspections will be approximately 50% of the conventional periodic inspection.

Especially when it comes to shortening the critical pass process.

Currently, the daily power generation cost of a 1100MW Wefi B W R is estimated to be about 100 million yen, so the power generation cost is expected to be about 100 million yen x 0.5m per day, or about 600 million yen, which is a huge effect.

[Effects of the Invention] According to the present invention, the remaining life time of a CRD can be determined with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is an embodiment diagram of the remaining life diagnosis device of the present invention, and FIG. 2 is a processing flow diagram of the CRD trend analysis subsystem of the present invention.
3 and 4 are processing flow diagrams of the CRD reliability analysis subsystem of the present invention, FIG. 5 is a processing flow diagram of the CRD remaining life comparison diagnosis subsystem of the present invention, and FIGS. Figure 8 is an example of the CRD trend analysis function test display screen of the present invention, Figure 9 is an example of the CRD trend analysis function test remaining life time comparison display screen, and Figures 10 and 11 are CRD reliability analysis accelerated test display screens. Example diagrams, Figures 1z to 15 are for each CR.
An example of the estimation display screen for each D, FIG. 16 is an example of the Weibull distribution plot data display screen, FIG. 17 is an example of the Weibull distribution analysis result display screen, FIG. 18 is an example of the remaining life diagnosis reliability analysis display screen, FIG. 19 is an example of a remaining life diagnosis analysis result display screen. 10... Trend analysis database section, 11... Central processing unit (computer), 12... Reliability analysis database section, 15... Auxiliary memory. Agent Patent Attorney Tadashi Akimoto Real figure figure figure figure figure figure figure figure figure i figure 2t remainder i figure figure figure i figure figure figure figure figure

Claims (1)

[Claims] 1. A first database unit storing plant name information, control rod drive mechanism (CRD) equipment information, control rod drive mechanism function test information, and remaining life diagnosis management target value information; a second database section for storing mechanism acceleration test information and Weibull distribution analysis information; a means for performing CRD trend analysis processing based on the information in the first database section to obtain trend remaining life; A control rod drive comprising: means for performing a CRD reliability analysis process based on the information to obtain a reliability remaining life; and a means for comparing the trend remaining life with the reliability remaining life to estimate the CRD remaining life. Mechanism remaining life diagnostic device. 2. The remaining life diagnostic device for a control rod drive mechanism according to claim 1, wherein the CRD remaining life based on the comparison is estimated using a minimum remaining life time. 3. The remaining life diagnosis device for a control rod drive mechanism according to claim 1, wherein the estimation is performed while displaying a remaining life image on a display screen.