JP2004219180A - Irradiation deterioration diagnostic method of nuclear reactor incore equipment and its system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate the remaining life of equipment based on actualy measured values from the viewpoint of soundness maintenance of the incore equipment in an atomic power plant or the like by sampling a material exposed to neutron irradiation of the nuclear reactor incore equipment as a test piece corresponding to evaluation object portion, operation period, test method or the like in the minimum range wherein a structural material function is not lost. <P>SOLUTION: This method has a sampling method determination process (S101) for determining a sample collection method for collecting for deterioration degree evaluation, a sampling process (S102) for collecting the test piece by the determined sampling method, a deterioration degree measuring process (S103) for performing a material test by using the collected test piece and evaluating the deterioration degree of the object portion from acquired data, and an evaluation process (S104) for evaluating the deterioration degree of the evaluation object portion by using the measured value. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention evaluates the remaining life of in-core equipment such as a nuclear power plant, and implements inspections and countermeasures at an appropriate time. The present invention relates to an irradiation deterioration diagnosis method and the same system.
[0002]
[Prior art]
In a nuclear power plant, material deterioration due to neutron irradiation accumulates with aging, and repair or replacement of in-furnace equipment may be required. In consideration of efficiency and cost, repairs and replacements should be performed before the furnace equipment is damaged, but if the repair / replacement time is set too safe, the cost merit may be impaired. Therefore, it is desired to develop a highly accurate evaluation method for repair / replacement time.
[0003]
Conventionally, a non-destructive diagnosis, such as a primary diagnosis for selecting a part to be inspected, a secondary diagnosis for predicting the progress of deterioration and a pre-service life, has been made as a complex diagnostic system for such reactor internal equipment 3 A technique for performing the following diagnosis has been proposed (for example, see Patent Document 1).
[0004]
However, in this conventional technique, since all the primary diagnoses are performed based on the database, a large amount of data is required to determine the target device. Further, the tertiary diagnosis based on the direct diagnosis is used for improving the accuracy of the secondary diagnostic device, but the secondary diagnosis is not used for determining the timing of performing the tertiary diagnosis. Further, this prior art does not disclose a specific sample collection site or a sample size when diagnosing a sample material.
[0005]
[Patent Document 1]
JP-A-11-23776
[Problems to be solved by the invention]
As a means for highly accurate evaluation of repair / replacement time in ordinary equipment, a method is known in which a test piece is collected from a site to be evaluated of the equipment and a material test is performed on the test piece. However, neutron-irradiated materials in nuclear reactor equipment are activated, so care must be taken in terms of exposure. Further, it is necessary to perform a test specimen to be sampled within a range that does not lose the function of the structural material.
[0007]
Therefore, in order to perform irradiation deterioration evaluation with high accuracy, it is desirable to perform deterioration diagnosis using a sampling material. However, from the viewpoint of reducing exposure and maintaining the function of a structure, it is desirable that a test piece to be sampled is small.
[0008]
The present invention has been made in view of such circumstances, and in order to maintain the integrity of in-core equipment such as a nuclear power plant, the remaining life of the equipment is evaluated, and inspection and countermeasures of the nuclear power plant are performed at an appropriate time. An object of the present invention is to provide a method and a system for diagnosing irradiation deterioration of equipment in a nuclear reactor, which can accurately grasp the state of deterioration of equipment at the present time.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is sufficient for performing a deterioration evaluation based on an evaluation target site, a test method, and an operation history in equipment in a nuclear reactor, and has an effect on a function of an evaluation target. A sampling method determining step of determining a sampling position, a sampling size, and a sampling number for sampling a minimum test piece in a range not to be performed, a sampling step of sampling a test piece from the relevant part of the actual machine according to the determined sampling method, and Material testing by all or some combination of electrochemical reactivation (EPR) measurement (hereinafter referred to as "EPR measurement"), microhardness measurement, radiation measurement and helium content measurement using test specimens Deterioration degree measuring step of performing, evaluation of IASCC (environmental stress corrosion cracking) susceptibility by the EPR measurement, and measurement of the microhardness An evaluation step of evaluating all of the mechanical properties and fracture toughness values, the neutron irradiation amount evaluation by the radiation measurement, and the weldability evaluation by the helium amount measurement, or the deterioration degree evaluation of the evaluation target site composed of a combination of some of them And a method for diagnosing irradiation degradation of equipment in a nuclear reactor.
[0010]
In the invention according to claim 2, for each target part of the irradiation deterioration diagnosis in the reactor internal equipment, at least the EPR measurement, the microhardness measurement, the gamma ray measurement, and the helium content analysis as the diagnostic test are required. A test piece size database for storing data related to test piece dimensions, a material database for storing data relating to the reactor operation period and past evaluation results for each of the target parts, and an input for specifying a device to be evaluated for irradiation deterioration diagnosis Means, the minimum required sample volume of the device to be evaluated based on the comparison with the data of each database corresponding to the device to be evaluated input from the input means, to obtain a sample collection method that does not cause any problem in the function of the device. Sampling method calculation means for calculating and outputting sample size, number of samples, and sampling position information The equipped, to provide a sampling method determination system, characterized by determining compatible sampling method for each target site of irradiation degradation diagnosis based on the input of the evaluation device to the input means.
[0011]
According to the third aspect of the present invention, the relation data between the EPR value and the IASCC sensitivity, the relation data between the microhardness and the 0.2% proof stress, the tensile strength and the fracture toughness value, the radiation measurement values of Co-60 and Mn-54 A database for deterioration diagnosis that stores analytic data of neutron irradiation dose and helium content and data on the relationship between welding heat input and welding cracks based on the EPR measurement, microhardness measurement, radiation measurement and helium content measurement data A measurement value input means for inputting, and an evaluation calculation means for comparing a measurement value input from the measurement value input means with data of the deterioration diagnosis database and performing an evaluation calculation corresponding to the measurement value, Test results for test pieces taken based on the number of samples and the sampling position determined by the sampling method determination system according to Item 2. By inputting to the input means, evaluation of IASCC sensitivity by EPR measurement, evaluation of mechanical properties and fracture toughness value by microhardness measurement, evaluation of neutron irradiation dose by radiation measurement of Co-60 and Mn-54, and helium content Provided is a system for diagnosing irradiation deterioration of equipment in a nuclear reactor, characterized in that the degree of deterioration composed of all or a part of the evaluation of weldability by measurement is determined.
[0012]
According to the present invention, a step of determining a method of collecting a minimum sample in a range that is sufficient for performing deterioration evaluation and does not affect the function of the evaluation target, and performing a material test using the collected sample to determine the degree of deterioration. By providing the step of evaluating, a minimum necessary sample can be collected from the actual in-furnace equipment to perform a material test, so that exposure can be reduced and a highly accurate deterioration diagnosis can be performed. Then, in order to minimize the number of test pieces to be collected, the sampling position, the sampling size, and the final number are determined, and then sampling is performed. In addition, the deterioration is evaluated by performing the measurement specialized for the necessary material characteristic values using the sampling material.In this deterioration evaluation, not only the deterioration of the material but also the evaluation of the neutron irradiation amount by radiation measurement and the irradiation It also includes evaluation of weldability for repair by measuring helium generation. Therefore, it is possible to perform an evaluation including the possibility of performing welding by using the neutron irradiation amount as a parameter.
[0013]
In the step of determining the method of collecting the sample, the step of determining the sample volume that needs to be collected from the dimensions of the test piece used for each test item, and the step of determining the sample to be collected from the information on the device to be evaluated and the required sample volume By determining the dimensions, the number of samples, and the sampling position, it is possible to collect the minimum number of samples necessary for the test without deteriorating the soundness of the structure, so that exposure can be reduced.
[0014]
In the step of performing a material test to determine the degree of deterioration, evaluation of IASCC sensitivity by the EPR method, evaluation of mechanical properties and fracture toughness by microhardness measurement, neutron irradiation by radiation measurement of Co-60 and Mn-54 By performing all or part of the combination of the evaluation of the weldability and the evaluation of the weldability by measuring the amount of helium, the evaluation of the IASCC susceptibility by the EPR method, the evaluation of the mechanical properties and the fracture toughness value by the measurement of the microhardness, Co-60 Deterioration diagnosis can be performed by combining all or a part of neutron irradiation dose evaluation by radiation measurement of Mn-54 and helium content measurement, or all or part of welding possibility evaluation. Can be.
[0015]
In the step of evaluating IASCC sensitivity by the EPR method, EPR measurement is performed using a sample collected based on the system according to claim 2, and the result is compared with a database on the relationship between the EPR value and IASCC sensitivity. By evaluating the IASCC susceptibility of the test piece, the EPR test can be performed using a sample collected from the equipment in the actual furnace, so that the IASCC susceptibility can be accurately evaluated.
[0016]
In the step of evaluating the fracture toughness value by measuring the microhardness, the microhardness is measured using a sample collected based on the system according to claim 2, and the result is compared with the microhardness and 0.2% proof stress. By evaluating the mechanical properties of the sample against all or part of the database on the relationship between tensile strength and fracture toughness, the microhardness measurement can be performed using the sample taken from the actual furnace equipment. Therefore, the mechanical properties can be accurately evaluated.
[0017]
Further, in the step of evaluating the neutron irradiation dose by measuring the radiation of Co-60 and Mn-54, the radiation dose is measured using a sample collected based on the system according to claim 2, and the result is used as the neutron irradiation dose. Since the neutron irradiation dose of the test specimen is evaluated by collating it with the analysis value database, it is possible to perform radiation measurement using samples taken from the actual furnace equipment. Can be.
[0018]
Further, in the step of welding possibility evaluation by measuring the helium content, the helium content is measured using a sample collected based on the system according to claim 2, and the result is compared with the helium content and welding heat input and welding crack. Since the possibility of welding work at the site where the sample was sampled is evaluated by collating with the database regarding the relationship, the He amount can be measured using the sample collected from the equipment in the actual furnace, so that welding of the sample can be accurately performed. Applicability can be evaluated.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a process diagram schematically showing a method of diagnosing irradiation deterioration of equipment in a nuclear reactor, and FIG. 2 is a process diagram extracting and showing the processing contents of the same process.
[0020]
As shown in FIGS. 1 and 2, the method according to the present embodiment is roughly divided into a sampling method determining step (S101) for determining a sampling method to be sampled for evaluating the degree of deterioration, and a test piece based on the determined sampling method. Sampling step (S102), a material test is performed using the collected test pieces, and a deterioration measuring step (S103) for evaluating the degree of deterioration of the target portion from the obtained data is performed. Evaluation step (S104) of evaluating the degree of deterioration of the target portion.
[0021]
First, in the sampling method determination step (S101), a minimum value within a range that does not affect the function of the evaluation target is sufficient to perform the deterioration evaluation based on the evaluation target site, the test method, and the operation history in the equipment inside the reactor. Determine the sampling position, sampling size and number of samples to be sampled. That is, the minimum volume of the test piece required for each test for performing the deterioration evaluation is determined, and based on this volume, the information and operation history of the equipment to be evaluated, the material database and past evaluation results are applied. Then, a specific sampling position, size and number are determined. At this time, the number of samples may be included in the determination item because there may be a plurality of samples due to restrictions on the sampling position and work efficiency.
[0022]
FIG. 3 shows the procedure of this sampling method determination step in detail. As shown in FIG. 3, for each target part of the irradiation deterioration diagnosis in the reactor internal equipment, at least the EPR measurement, microhardness measurement, gamma ray measurement and helium content analysis as the diagnostic test are required. A test piece size database 1 for storing data on test piece size is applied.
[0023]
Then, a material database 2 for storing data relating to the reactor operation period and past evaluation results for each evaluation target portion, input means 3 for specifying an evaluation target device for irradiation deterioration diagnosis, and input from the input means 3 The minimum required sample volume of the device to be evaluated is determined based on the comparison with the data of the databases 1 and 2 corresponding to the device to be evaluated.
[0024]
Further, the sampling method calculating means 4 calculates a sampling method having no problem in the function of the device, and determines a sampling method suitable for each target part of the irradiation deterioration diagnosis with respect to the sample size and number, the sampling position, and the like. And output that information.
[0025]
Next, in the sampling step (S102), as shown in FIG. 1 and FIG. 2, according to the sample size, the number of samples, and the sampling position determined in the sampling method determination step (S101), the actual part of the reactor 5 is used. A test piece 6 is collected.
[0026]
In the deterioration degree measuring step (S103), the EPR value measurement (S103a), microhardness measurement (for example, nano-universal hardness measurement) (S103b), and the helium content of the test piece 6 collected in the sampling step (S102) Analysis (measurement of transmuted helium amount) (S103c), radiation measurement of gamma rays (for example, radiation measurement values of Co-60 and Mn-54) (S103d), and the like are performed.
[0027]
Then, in the evaluation step (S104), the degree of deterioration of the evaluation target portion is evaluated by collating the measured values measured in the degree of deterioration measurement step (S103) with the deterioration diagnosis database 7.
[0028]
That is, the deterioration diagnosis database 7 includes data on the relationship between the EPR value and the IASCC sensitivity, data on the relationship between microhardness and 0.2% proof stress, tensile strength and fracture toughness, and radiation of Co-60 and Mn-54. Analytical data of the neutron irradiation dose based on the measured values, helium content, and data on the relationship between welding heat input and welding cracks are stored.
[0029]
Then, the deterioration diagnosis database 7 and the measured values such as the EPR measurement value, the microhardness measurement value, the radiation measurement value, and the helium content input from the measurement value input means 8 are input to the calculation means 9, and the calculation means In 7, the degree of deterioration of the evaluation target portion is evaluated by comparing the input value from the measured value input means 8 with the data in the deterioration diagnosis database 7.
[0030]
As described above, in the present embodiment, the sampling position, the sampling size, and the number of samples are determined in the sampling method determination step, sampling is performed from the in-furnace equipment in accordance with the determination, and then the EPR test is performed using the sampled sample, All or part of the microhardness measurement, the radiation measurement, and the He amount measurement are performed, and the degree of deterioration of the test piece is evaluated. This result is used directly, or the deterioration diagnosis of the target in-furnace equipment is performed by comparing with the existing database.
[0031]
FIG. 4 is an explanatory diagram showing an example of the relationship between the EPR value and the IASCC sensitivity described above. As shown in FIG. 3, the EPR value and the IASCC sensitivity have a proportional relationship, and the test result 6 is applied to the diagram showing the relational expression or relation obtained from the deterioration diagnosis database 7 by using the measurement result. The specimens are collected and the IASCC sensitivity of the specimen collection section is evaluated.
[0032]
FIGS. 5A and 5B are graphs showing a relationship between a measured value of microhardness and a 0.2% proof stress and a relationship between a measured value of microhardness and a fracture toughness value as examples of mechanical property evaluation. is there. As shown in FIGS. 4A and 4B, the measured value of microhardness is proportional to the 0.2% proof stress, and the measured value of microhardness and the fracture toughness are quadratic curves. In a gradually decreasing relationship. The measurement result is applied to a relational expression or a diagram showing the relation obtained from such a database, and the mechanical properties of the test piece sampling unit are evaluated.
[0033]
FIG. 6 is an evaluation diagram of welding feasibility using He amount and welding heat input as parameters. As shown in FIG. 5, the relationship between the He amount and the welding heat input gradually decreases in a quadratic curve. Therefore, the obtained He amount of the evaluation target portion and the heat input of the assumed welding method are plotted, and if that point is within the weldable region, it is determined that welding can be performed.
[0034]
In the present embodiment, a computer is applied as the sampling method calculation means 4, but a part or all of the evaluation can be performed manually.
[0035]
The evaluation is performed by all or some of the methods shown as examples of the deterioration diagnosis in FIG. Then, an overall evaluation is performed by combining the individual results obtained at the end. As the neutron dose increases, the IASCC sensitivity increases and the fracture toughness decreases. That is, it indicates that the defects caused by the IASCC increase with an increase in the operation period, and the defect size that can be tolerated by the equipment decreases. If repair is determined to be necessary based on both results, the possibility of welding repair is evaluated based on the He amount and neutron irradiation amount at that time.
[0036]
As described above, the sampling method determination system according to the present embodiment includes, as means for performing the sampling method determination step (S101), EPR measurement as a diagnostic test for each irradiation degradation diagnosis target in the reactor internal equipment. Specimen size database 1 that stores the minimum required specimen size data for microhardness measurement, gamma ray measurement, and helium content analysis, and data on past evaluation results for each reactor operation period and target site. Material database 2 to be stored, input means 3 for specifying a device to be evaluated for irradiation deterioration diagnosis, and minimum required based on collation with data of each database corresponding to the device to be evaluated input from input device 3 Calculate the sample volume of the device to be evaluated, calculate the sample A sampling method calculating means for outputting pull dimensions, the number of samples, and sampling position information; and determining a sampling method suitable for each target part of the irradiation deterioration diagnosis based on the input of the evaluation target equipment to the input means. Things.
[0037]
In addition, the irradiation deterioration diagnosis system of the present embodiment includes relation data between EPR value and IASCC sensitivity, relation data between microhardness and 0.2% proof stress, tensile strength and fracture toughness, Co-60 and Mn-54. A deterioration diagnosis database 7 for storing analysis value data of neutron irradiation dose and helium content based on the measured values of radiation and relation data between welding heat input and welding cracking; EPR measurement, microhardness measurement, radiation measurement and helium content A measurement value input unit 8 for inputting a measured value of the amount, an evaluation operation for collating the measured value input from the measured value input unit 8 with seven data of the deterioration diagnosis database, and performing an evaluation operation corresponding to the measured value Means 9. Then, by inputting the test result to the measurement value input means 8 for the test piece taken based on the number of samples and the sample taking position determined by the above-described sampling method determination system, the evaluation of IASCC sensitivity by EPR measurement, Evaluation of mechanical properties and fracture toughness by microhardness measurement, evaluation of neutron irradiation dose by radiation measurement of Co-60 and Mn-54, and evaluation of weldability by helium content measurement This is to determine the degree of deterioration.
[0038]
According to the above-described embodiment, since a material test can be performed by sampling a minimum necessary number of test pieces 6 from the actual furnace equipment, it is possible to obtain an irradiation deterioration diagnosis system having both reduced exposure and high accuracy. it can. In addition, since a minimum number of test pieces 6 necessary for the test can be collected without deteriorating the soundness of the structure, an irradiation deterioration diagnosis system with reduced exposure can be obtained.
[0039]
In addition, EPR test, microhardness measurement, radiation measurement, He amount measurement, etc. are performed using test specimens collected from actual furnace equipment. The deterioration degree of a plurality of items can be evaluated, and a highly accurate and complex irradiation deterioration diagnosis system can be obtained.
[0040]
【The invention's effect】
As described above, according to the present invention, the neutron-irradiated material in the reactor equipment is evaluated in accordance with the site to be evaluated, the operation period, the test method, etc. Samples can be sampled within the range, and the remaining life of the equipment can be evaluated based on the measured values in order to maintain the soundness of in-core equipment such as a nuclear power plant. Therefore, there is an effect that the state of deterioration of the device at the present time can be accurately grasped.
[Brief description of the drawings]
FIG. 1 is an overall explanatory diagram for explaining a deterioration diagnosis method according to an embodiment of the present invention.
FIG. 2 is a process chart showing a deterioration diagnosis procedure according to an embodiment of the present invention.
FIG. 3 is a process chart showing a procedure for determining a sample collection method according to an embodiment of the present invention.
FIG. 4 is a graph showing the relationship between EPR values and IASCC sensitivity.
FIGS. 5A and 5B are graphs showing the relationship between microhardness and mechanical properties.
FIG. 6 is a graph showing an example of evaluation of welding possibility based on He amount.
[Explanation of symbols]
1 Specimen size database 2 Material database 3 Input means 4 Sampling method calculation means 5 Reactor 6 Specimen 7 Deterioration diagnosis database 8 Measured value input means 9 Calculation means

Claims (3)

Sampling position and sampling location for sampling the smallest test specimen that is sufficient to perform deterioration evaluation based on the evaluation target site, test method, and operation history in the reactor internal equipment and that does not affect the function of the evaluation target A sampling method determining step of determining dimensions and the number of samples, a sampling step of collecting a test piece from the relevant part according to the determined sampling method, and EPR measurement, microhardness measurement, radiation measurement and Deterioration degree measurement step of performing material test by all or part of combination of helium content measurement, evaluation of IASCC susceptibility by EPR measurement, evaluation of mechanical properties and fracture toughness value by microhardness measurement, radiation measurement All of the neutron irradiation dose evaluation by and the evaluation of the weldability by the helium content measurement, or Irradiation degradation diagnosis method of the reactor furnace device, characterized in that it comprises an evaluation step for Quality Evaluation of the evaluation target part consisting of a combination of parts, the. For each target part of the irradiation deterioration diagnosis in the equipment inside the reactor, data on the minimum required test specimen dimensions for EPR measurement, microhardness measurement, gamma ray measurement and helium content analysis as the diagnostic test are stored. A test piece size database, a material database for storing data relating to the reactor operation period and past evaluation results for each of the target parts, input means for specifying an evaluation target device for irradiation deterioration diagnosis, and input from the input means The minimum required sample volume of the device to be evaluated is determined based on the comparison with the data of each database corresponding to the device to be evaluated, and the sample size and the sample are calculated by calculating the sample collection method that does not cause any problem in the function of the device. And a sampling method calculating means for outputting the number and sampling position information. Sampling method determination system, characterized by determining compatible sampling method for each target site of irradiation degradation diagnosis based on the input of the evaluation device. Relationship data between EPR value and IASCC sensitivity, relationship data between microhardness and 0.2% proof stress, tensile strength and fracture toughness value, analysis value of neutron dose based on radiation measurement values of Co-60 and Mn-54 A database for deterioration diagnosis that stores data and data relating to the amount of helium and welding heat input and welding cracks, and a measurement value input unit that inputs measurement values of EPR measurement, microhardness measurement, radiation measurement and helium content, 3. The sampling method determination system according to claim 2, further comprising: evaluation operation means for comparing a measured value input from the measured value input means with data of the deterioration diagnosis database and performing an evaluation operation corresponding to the measured value. The test result of the test piece sampled based on the sample number and the sample sampling position determined by the above is input to the input means. Evaluation of IASCC sensitivity by EPR measurement, evaluation of mechanical properties and fracture toughness value by microhardness measurement, evaluation of neutron irradiation dose by radiation measurement of Co-60 and Mn-54, and weldability by helium content measurement An irradiation deterioration diagnosis system for equipment in a nuclear reactor, wherein the deterioration degree is determined by a combination of all or some of the evaluations.

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