WO2019104510A1

WO2019104510A1 - Method and device for evaluating degree of neutron irradiation embrittlement of nuclear power plant reactor pressure vessel

Info

Publication number: WO2019104510A1
Application number: PCT/CN2017/113491
Authority: WO
Inventors: 束国刚; 李承亮; 徐贲; 陈骏; 段远刚; 刘伟; 邓小云; 冉小兵; 刘飞华
Original assignee: 中广核工程有限公司; 中国广核集团有限公司
Priority date: 2017-11-29
Filing date: 2017-11-29
Publication date: 2019-06-06
Also published as: GB202009909D0; GB2583292A8; GB2583292A; GB2583292B

Abstract

A method and device for evaluating the degree of neutron irradiation embrittlement of a nuclear power plant reactor pressure vessel. The initial electrical resistivity of the steel of a reactor pressure vessel is measured and the electrical resistivity of the steel of the reactor pressure vessel of any arbitrary point in time after being embrittled by neutron irradiation is acquired in real-time to calculate the macroscopic mechanical properties and/or neutron irradiation fluence; and, the degree of irradiation embrittlement of the reactor pressure vessel is analyzed and evaluated on the basis of the macroscopic mechanical properties and/or neutron irradiation fluence. The method and device are economical, environmentally friendly, safe, and highly efficient, allow real-time monitoring of the degree of irradiation embrittlement of a specific part of the reactor pressure vessel, and allow simultaneous monitoring of the degree of irradiation embrittlement of multiple parts of the reactor pressure vessel.

Description

\¥0 2019/104510 卩(:17 \2017/113491

1

Nuclear power plant reactor pressure vessel neutron irradiation embrittlement assessment method and device

Technical field

[0001] The present invention relates to the field of safe operation of nuclear power plant reactor pressure vessels, and more particularly to a method and apparatus for assessing the degree of neutron embrittlement in a nuclear power plant reactor pressure vessel.

Background technique

[0002] Reactor pressure vessels are one of the most critical large-scale equipment in a nuclear power plant nuclear island. The main function is a steel pressure vessel that contains and supports core nuclear fuel assemblies, control rod assemblies, internal reactor components, and reactor coolant. It is used for long-term exposure to strong radiation, high temperature and high pressure environments. Among them, neutron irradiation embrittlement (specifically, the yield strength and non-ductile transition temperature increase during irradiation embrittlement of reactor pressure vessel steel) is one of the main failure modes.

[0003] In order to ensure the safety of reactor pressure vessel operation, it is one of the commonly used methods to monitor and evaluate the degree of irradiation embrittlement. The specific implementation steps are as follows: (1) Before the nuclear power plant is loaded for the first time, install 4 to 6 irradiation supervision tubes inside the reactor pressure vessel, and each irradiation supervision tube is loaded with a fluence detector and a certain amount of tensile and impact. (1) According to the irradiation supervision tube extraction plan formulated by the irradiation supervision program, use the opportunity of refueling and maintenance of the nuclear power plant, periodically extract the irradiation supervision tube from the reactor pressure vessel, and then lead according to the radiation protection requirements. After the tank is packaged, it is transported long distance to the fixed-point hot chamber mechanism, and the mechanical probe samples such as tensile and impact are taken out by cutting and dissecting. Then, the components of the fluence detector are analyzed in the hot chamber, and the mechanical properties of the mechanical properties are carried out. The test, in turn, calculates the neutron irradiation fluence and mechanical properties data obtained by the fluence detector. (3) Conduct safety evaluation on the operation of reactor pressure vessels based on neutron irradiation fluence and mechanical property data.

[0004] However, the above existing methods have the following disadvantages:

[0005] (1) Limited by the internal space of the reactor pressure vessel, the number of mountable irradiation supervisory tubes is very limited, and it is not possible to supervise multiple parts of the reactor pressure vessel (including specific parts);

[0006] (2) Since the number of irradiation supervision tubes is very limited, it usually only has 4 to 6 and must be loaded once before the first loading operation. The prior art cannot be re-installed after running for a period of time. Irradiation \¥0 2019/104510 卩(:17€\2017/113491

2 Supervising the pipe, therefore, the neutron irradiation fluence of the reactor pressure vessel steel cannot be continuously obtained; at the same time, it takes a certain time for the irradiation supervision pipe to take, transport, cut anatomy, fluence detector test analysis, etc. The method has obtained obvious hysteresis in the degree of irradiation embrittlement of the reactor pressure vessel steel.

_{[0007] (4) A} large amount of radioactive waste is generated in the test and analysis section, and the subsequent three wastes are processed in a large amount and the cost is high;

_{[0008] (5) The} above method can only monitor the neutron irradiation embrittlement degree of the reactor pressure vessel core area as a whole, and does not have the function of monitoring other components of the reactor pressure vessel, especially the degree of irradiation embrittlement of a specific part.

_[0009] Therefore, it is necessary to provide an economical, environmentally friendly, safe, high-efficiency, real-time monitoring method for neutron irradiation embrittlement of nuclear power plant reactor pressure vessels in various parts of reactor pressure vessels.

technical problem

0 _010] The present invention provides an economical, environmentally friendly, safe, high-efficiency, real-time monitoring of reactor pressure vessels for various problems in the method of monitoring and evaluating the degree of irradiation embrittlement of reactor pressure vessel steel by the above conventional irradiation supervision method. Method and apparatus for neutron irradiation embrittlement assessment of nuclear power plant reactor pressure vessels with multiple locations and certain specific locations.

Problem solution

Technical solution

[ _0011] The technical solution proposed by the present invention with respect to the above technical problems is as follows:

_{[0012] In} one aspect, a method for evaluating neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel is provided, comprising the steps of:

_{[0013] 1} , establish a benchmark: measured the initial resistivity of the reactor pressure vessel steel ^

_{[0014] 82} , real-time monitoring: during the normal operation of the nuclear power plant, real-time acquisition of the resistivity of the reactor neutron irradiation embrittlement of the reactor pressure vessel steel at any time point ^

_{[0015] 33} , analytical calculation: based on the initial resistivity and real-time acquisition of the resistivity of the reactor pressure vessel steel after irradiation embrittlement _£ > obtaining the macroscopic pressure of the reactor pressure vessel steel in the process of irradiation embrittlement Mechanical properties; and _/ or, the neutron irradiation fluence of the reactor pressure vessel steel;

_{[0016] 84.} Safety Assessment: The degree of irradiation embrittlement of the reactor pressure vessel is evaluated based on the macroscopic mechanical properties and _/ or the reactor neutron irradiation fluence analysis of the pressure vessel steel. \¥0 2019/104510 卩(:17 \2017/113491

3

[0017] Preferably, in step 32, the resistivity after the neutron irradiation embrittlement of the same portion of the reactor pressure vessel steel at any time point is obtained in real time.

[0018] Preferably, the macroscopic mechanical property is a real-time yield strength

At least one of them.

[0019] Preferably, in step 33, calculating the real-time yield strength of the reactor pressure vessel steel in the irradiation embrittlement according to the formulas (1)-(2)

At least one of the formulas, wherein the formulas (1)-(2) are:

[0021] /^ _■ = eight ₂ +6 ₂ . ^>(2);

[0022] Among them: eight! , 8 ₂ , : 8 _! and all coefficients.

[0023] Preferably, for a specific nuclear power plant and reactor pressure vessel, said, ₂ , : 8 ₁ and 6 ₂ can be used to test the mechanical property data of the mechanical property sample by the conventional irradiation supervision method, and the initial pressure reactor steel The resistivity is determined or corrected.

[0024] Preferably, the security evaluation process in step 34 is: the real-time yield strength /? and real-time non-ductile transition temperature

At least one of the parameters is used as an analytical input parameter, and the degree of irradiation embrittlement of the reactor pressure vessel is evaluated in accordance with the analytical input parameter.

[0025] Preferably, in step 33, the neutron irradiation fluence of the reactor pressure vessel steel is calculated based on formula (3), and the formula (3) is:

[0026] 0 = eight ₃ + 6 ₃ . (> + (: · ^ (3);

[0027] wherein, ø is a neutron irradiation fluence of the reactor pressure vessel steel; 八₃ , :8 ₃ , (: are proportional factors.

[0028] Preferably, for a particular nuclear power plant and reactor pressure vessel, said ₃ , :8 ₃ , (: radiation fluence data obtainable by conventional irradiation supervision methods, and initial resistivity of reactor pressure vessel steel) Determine or correct.

[0029] Preferably, the safety evaluation process in step 34 is: using the reactor pressure vessel steel neutron irradiation fluence 0 as an analysis input parameter, and irradiating the reactor pressure vessel according to the analysis input parameter Degree of security assessment.

[0030] Preferably, in the step, the initial resistivity is measured by: after the reactor pressure vessel is installed in position, and before the nuclear power plant is first loaded, the initial pressure of the reactor pressure vessel steel is measured. \¥0 2019/104510 卩(:17€\2017/113491

4 resistivity ^.

_[0031] Preferably, the process of evaluating the degree of irradiation embrittlement of the reactor pressure vessel according to the macroscopic mechanical properties and _/ or the neutron irradiation fluence analysis of the reactor pressure vessel steel comprises: setting a preset condition, when The macroscopic mechanical properties and _/ or the reactor neutron irradiation fluence of the reactor pressure vessel steel are issued an early warning when the predetermined condition is met.

_{[0032] In} another aspect, an apparatus for evaluating neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel is also provided,

_[0033] comprising: a monitoring unit and an evaluation unit;

_{[0034] The} monitoring unit is connected at one end to the reactor pressure vessel for monitoring the resistivity of the reactor pressure vessel steel, and the other end is connected to the evaluation unit;

_{[0035] The} evaluation unit is configured to calculate macroscopic mechanical properties of the reactor pressure vessel steel during irradiation embrittlement according to the monitored resistivity of the reactor pressure vessel steel, and according to the macroscopic mechanical properties The change in data is a safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel;

_[0036] and _/ or, calculating the neutron irradiation fluence of the reactor pressure vessel steel according to the measured resistivity of the reactor pressure vessel steel, and according to the change of the neutron irradiation fluence of the reactor pressure vessel steel A safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel is performed.

_[0037] Preferably, the evaluation unit comprises:

_{[0038] a} storage unit, configured to store a resistivity of the reactor pressure vessel steel detected by the detecting unit;

_{[0039] a} calculation unit for calculating a macroscopic mechanical property of the reactor pressure vessel steel during irradiation embrittlement according to the detected resistivity of the reactor pressure vessel steel; and _/ or The resistivity of the reactor pressure vessel steel is calculated to obtain the neutron irradiation embrittlement fluence of the reactor pressure vessel steel

_[0040] and a judging unit for performing a safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to the calculated change in macroscopic mechanical properties of the reactor pressure vessel steel in irradiation embrittlement; _/ or, a safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel is made based on changes in the neutron irradiation fluence of the reactor pressure vessel steel.

_[0041] Preferably, further comprising a display unit connected to the evaluation unit for displaying a result of performing safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to the macroscopic mechanical property, and _/ Or, irradiating the reactor pressure vessel with the neutron irradiation fluence of the reactor pressure vessel steel \¥0 2019/104510 卩(:17€\2017/113491

5 The degree of safety assessment results.

Advantageous effects of the invention

Beneficial effect

_[0042] The technical solution of the present invention has the following technical effects:

_{[0043] (1)} real-time, online, and continuous monitoring of the resistivity of the reactor pressure vessel steel during the operation of the nuclear power plant, and real-time calculation of the macroscopic mechanical and _/ or neutron radiation amount data of the reactor pressure vessel steel;

_{[0044] (2)} Since the physical property (resistivity) test of the reactor pressure vessel steel is non-destructive, the data can be acquired indefinitely during the full life of the nuclear power plant, including during the future life extension operation;

_{[0045] (3) The} monitoring equipment and operation do not require special radiation safety protection requirements, and there is basically no requirement for the external space of the equipment, and the cost is low and the safety is good, especially no radioactive waste is generated, and there is basically no need for three waste disposal;

_{[0046] (4)} Simultaneously monitoring the degree of irradiation embrittlement at a plurality of locations of the reactor pressure vessel, and is particularly suitable for monitoring the initiation of microcracks or suspected microcracks found during the in-service inspection of the reactor pressure vessel during the refueling overhaul of the nuclear power plant. Extended behavior.

Brief description of the drawing

DRAWINGS

_[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are only some of the present invention. For the embodiments, those skilled in the art can obtain other drawings according to the drawings without any creative work.

_[0048] FIG. 1 is a flowchart illustrating a step of irradiation embrittlement degree neutron nuclear reactor pressure vessel according to a first embodiment of the evaluation method of the present invention;

Figure

_[0051] FIG. ₄ is an embodiment of the present invention, five, six resistivity provided by neutron irradiation fluence diagram;

_[0052] FIG. 5 is a schematic structural evaluation device irradiation embrittlement degree neutron reactor pressure vessel according to a seventh embodiment of the present invention is provided. \¥0 2019/104510 ?€1^2017/113491

6 Invention embodiment

Embodiments of the invention

[0053] The present invention is directed to the above problems existing in the irradiation embrittlement monitoring technology of the existing reactor pressure vessel,

[0054] An economical, environmentally friendly, safe, and efficient method and apparatus for neutron irradiation embrittlement assessment of nuclear power plant reactor pressure vessels capable of real-time monitoring of multiple parts of a reactor pressure vessel and irradiation of certain specific parts. The core idea is: to obtain the macroscopic mechanical properties and/or neutron irradiation fluence of the reactor pressure vessel steel by monitoring the change of the resistivity of the reactor pressure vessel steel during the operation of the reactor pressure vessel, and then to evaluate the irradiation of the reactor pressure vessel. The degree of embrittlement is used to carry out safety evaluation and life prediction of structural integrity during irradiation embrittlement of reactor pressure vessels.

[0055] Embodiment 1:

[0056] FIG. 1 shows an evaluation method for the degree of neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel (through macroscopic mechanical properties):

[0057] 1. Establish a benchmark: The initial resistivity of the reactor pressure vessel steel is measured; specifically, the "four-lead method (also known as four-point method or four-terminal method)" can be used to measure the position of the reactor pressure vessel core region. The initial resistivity of the steel can also be measured by other conventional methods. In this embodiment, the initial resistivity of the plurality of different specific positions of the reactor pressure vessel steel can be simultaneously obtained; preferably, The initial resistivity is measured as follows: After the reactor pressure vessel is installed in place, and before the nuclear power plant is first charged, the initial resistivity of the reactor pressure vessel steel is measured;

[0058] 82, real-time monitoring: during the normal operation of the nuclear power plant, real-time acquisition of the reactor at any time point

[0059] The resistivity of the pressure vessel steel after neutron irradiation embrittlement ^ Specifically, the "four-lead method (also known as four-point method or four-end method)" can be used to measure the same pressure of the reactor pressure vessel after embrittlement The real-time resistivity of the part is also determined by other conventional methods. The resistivity of the reactor pressure vessel steel after irradiation embrittlement is corresponding. When the initial resistivity of different parts is obtained at the same time, each time can be obtained in real time. The real-time resistivity at a portion is 0, that is, for the same portion, the initial resistivity and the resistivity after neutron irradiation embrittlement of the reactor pressure vessel steel at any point in time can be obtained, thereby The neutron irradiation fluence of the specific position of the reactor pressure can be continuously and simultaneously monitored; the initial resistivity and the resistivity unit of the reactor neutron irradiation embrittlement of the reactor pressure vessel steel are generally selected as 10

[0060] 33, analytical calculation: based on the initial resistivity and real-time acquisition of the reactor pressure vessel steel \¥0 2019/104510 卩(:17€\2017/113491

7 Resistivity after sub-radiation embrittlement ^ Calculate the reactor pressure vessel steel in the irradiation brittle by formula (1)-(2)

_[0063] wherein: , , ₂ , : ₈ , and both are coefficients, the value of the body may be based on the microstructure characteristics of the initial state of the reactor pressure vessel steel (such as grain size, dislocation type, quantity, second phase distribution) Characteristics, etc.), initial high temperature yield strength, initial ductile transition temperature, and reactor neutron irradiation during nuclear power plant operation

The range of values is generally [85, 215]; the range of values of 八₂ is generally [-16 _{7, -82];} : _{8 2}

The range of values is generally _{[73, 182]} . For specific nuclear power plants and reactor pressure vessels, above, 8 ₂

The initial resistivity of the reactor pressure vessel steel is determined or corrected.

_{[0064] In the} present embodiment, the value of 八_! is _-74.96 , : _{8 ! The} value is 156.6 ₇ , and the formula (1) thus obtained is _/? _^ = 156.6 ₇ ^- _74.96 ; further, the reactor is measured. The resistivity of the reactor vessel pressure steel after neutron irradiation embrittlement of the pressure vessel steel during operation (> _{3.63\10 - 7} 〇· _! ^ The real-time yield strength of the reactor pressure vessel steel is obtained by the formula ( ₁ ) _/? is 494MPa (hereinafter referred to as the calculated value).

It is 502 MPa (measured value). It can be seen that the calculated value deviation is only 1.6% relative to the measured value.

, meet the requirements.

_[0065] Embodiment 2:

_[0066] The present embodiment is different from the embodiment only in one embodiment, the measured steel reactor pressure vessel during operation of the reactor pressure vessel resistivity after neutron irradiation embrittlement of steel _£> 4.14 \ 10

(hereinafter referred to as the calculated value). The mechanical properties of the sample by irradiating the supervision of traditional ISCs and get real-time measurement of yield strength _/? Is 565MPa (measured value). It can be seen that the deviation of the calculated values is also only 1.6% with respect to the measured values, which is in compliance with the requirements. \¥0 2019/104510 卩(:17€\2017/113491

8

_[0067] Thereby, the real-time yield strength of the reactor pressure vessel steel of a specific nuclear power plant shown in FIG. ₂ can be obtained.

_[0068] Degree "variation curve. Among them, the black solid point is the radiation supervision mechanics in the traditional irradiation supervision tube

_[0069] The measured data obtained by the performance sample was measured, and the black straight line was obtained by the formula ( ₁ ) of the first and second examples to obtain the real-time yield strength _/? curve of the reactor pressure vessel steel.

_[0070] Embodiment 3:

_[0071] This embodiment differs from the first embodiment only in that the macroscopic mechanical property is a real-time non-ductile transition temperature. Similarly, in this embodiment, the value of eight is _-121.65 , and the value of ₈ is _116.79 .

The unit of measure, rather than the usual Celsius temperature unit, is converted to the following relationship: Absolute temperature ( _X ) = ₂₇₃ + Celsius (: °). And the actual measurement of the mechanical properties of the radiation in the traditional irradiation supervision tube

In terms of value, the calculated value deviation is only _7.5% , which meets the requirements.

_[0072] Embodiment 4:

_[0073] The present embodiment differs from the embodiment according to a third embodiment only in that the reactor pressure vessel steel measured during operation of the reactor pressure vessel resistivity after neutron irradiation embrittlement of steel _£> _{4.14 \ 10}

Is ₃₆₂ :^ (hereinafter referred to as the calculated value). The mechanical properties of the sample by irradiating the supervision of traditional ISCs and get real-time measurement of non-ductility transition temperature _{/? 7 \ ^} ₃₇₃ (measured value). It can be seen that the deviation of the calculated value is only _3.0% relative to the measured value, which is in compliance with the requirements.

_[0074] Thereby, the real-time non-ductile transition temperature of the reactor pressure vessel steel of a specific nuclear power plant shown in FIG. 3 can be obtained.

The measured data obtained by the actual measurement of the performance samples, the black straight line is obtained by the formula (2) of the third and fourth embodiments.

\¥0 2019/104510 卩(:17 \2017/113491

9

_1.2 , real-time non-ductile transition temperature /? 7 \ ^ and the real-time yield strength measured by the traditional method /? ₂ , real-time non-ductile transition temperature /? 7 ^ ^ are very close, the deviation is completely acceptable Within the scope, there will be no impact on the safety assessment of the degree of embrittlement of subsequent reactor pressure vessels.

[0076] It should be noted that, in the present invention, the real-time yield strength/? is obtained by formula (1) - (2).

The solution is one of the important inventions of the present invention by the inventors through repeated verification and creative labor. No identical or similar solutions are disclosed in the prior art.

[0077] Further, the security evaluation process in step 34 is: the real-time yield strength _{. 2} and the real-time non-ductile transition temperature.

At least one of the following is an analysis input parameter, and a safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel is performed according to the analytical input parameter, the safety assessment including structural integrity safety evaluation, life prediction, and the like. More specifically, the step of performing safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to the analysis input parameter comprises: setting a preset condition, when the value of the analysis input parameter satisfies the preset When conditions are met, an alert is issued.

[0078] The technical solution of this embodiment has the following technical effects:

[0079] (1) The resistivity of the reactor pressure vessel steel during the operation of the nuclear power plant can be tested in real time, and the change of the mechanical property data of the reactor pressure vessel steel can be obtained in real time;

[0080] (2) Since the resistivity test of the reactor pressure vessel steel is non-destructive, the data can be acquired indefinitely during the full life of the nuclear power plant, including during the future life extension operation;

[0081] (3) The test equipment and operation do not require special radiation safety protection requirements, and the test equipment has no special requirements for the external space, low cost and good safety, especially no radioactive waste, and basically no three waste disposal requirements;

[0082] (4) The degree of irradiation embrittlement of the reactor pressure vessel can be monitored at the same time, and is particularly suitable for monitoring the initiation of microcracks or suspected microcracks found during the in-service inspection of the reactor pressure vessel during the overhaul of the nuclear power plant. Extended behavior.

Embodiment 5:

1 shows a method for evaluating the degree of neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel (by neutron irradiation fluence), which differs from the first embodiment in that, in step 33, The reaction can be calculated based on the real-time obtained resistivity of the reactor pressure vessel steel neutron irradiation embrittlement and the formula (3) \¥0 2019/104510 卩(:17€\2017/113491

10 reactor pressure vessel steel neutron irradiation fluence; specifically, the formula ( ₃ ) is:

. _[0085] 0 = _{3 + 63} eight (> ₊ (: * ^ (3);

_[0086] wherein, the ø (unit is \10 _3⁄4 _/ 〇 ₁₁ ² ₃ > _{6 ¥} ) is the neutron irradiation fluence of the reactor pressure vessel steel; 八₃ , : _{8 3} , (: are all coefficients, 八₃ The range of values is generally _[51,112]; : _{8 3} is generally in the range _{[27, 74];} (: the range is generally _{[-11, -1]} . The specific value can be based on reactor pressure The microstructure characteristics of the initial state of the container steel (such as grain size, type of dislocation, quantity, distribution characteristics of the second phase, etc.), and the energy spectrum of the reactor neutron irradiation field during the operation of the nuclear power plant are comprehensively determined, for specific nuclear power plants and Reactor pressure vessel, ₃ _{,: 83} , (: can be determined or corrected by the radiation fluence data obtained by the traditional irradiation supervision method test fluence detector, and the initial resistivity of the reactor pressure vessel steel.

_{[0087] In} this embodiment, the value of ₃ is -86.40, and the value of _{8 3} is 43.52, (: the value is -4.9 ₇ , thereby obtaining the formula (3) is 0=-86.4〇 _+43.52 ^4.9 ₇ Further measuring the resistivity of the reactor pressure vessel steel after the neutron irradiation embrittlement of the reactor pressure vessel steel (> 3.63\10)

□ _{• 111,} whereby the neutron irradiation fluence of the reactor pressure vessel steel obtained by the formula (3) is _2.776x10 n/cm^E>lMeY (hereinafter referred to as the calculated value). The irradiation fluence obtained by conventional irradiation supervision methods (such as by a neutron fluence detector) is 2.9 _7x10 ¹ 3⁄4 _/cm ² , E>lMeV (measured value). It can be seen that the calculated value deviation is only 6.5% relative to the measured value, which meets the requirements.

_[0088] Embodiment 6:

_[0089] The present embodiment differs from the embodiment according to the fifth embodiment only in that the reactor pressure vessel steel measured during operation of the reactor pressure vessel resistivity after neutron irradiation embrittlement of steel _£> 4.14 \ 10

□ _{• 111,} whereby the neutron irradiation fluence of the reactor pressure vessel steel obtained by the formula (3) is 8.39x10 n/cm^E>lMeY (hereinafter referred to as the calculated value). Through traditional irradiation supervision methods (such as through neutrons)

See, the calculated value deviation is only 0.8% relative to the measured value, which meets the requirements.

_[0090] Accordingly, the irradiation fluence neutron steel container of FIG. 4 can be obtained for a specific nuclear power plant reactor pressure shown ø change curve. Wherein, the black solid point is the irradiation fluence data obtained by the conventional irradiation supervision method (such as by a neutron fluence detector), and the black straight line is the reactor pressure vessel steel obtained by the formula ( ₃ ) of the fifth and sixth embodiments. The neutron irradiation flu curve ø. \¥0 2019/104510 卩(:17€\2017/113491

11

_[0091] As can be seen from FIG. ₄ , the neutron irradiation fluence ø obtained by the formula ( _{3) of the} present invention is very close to the neutron irradiation flu measured by the conventional method, and the deviation value is completely Within the acceptable range, there is no impact on the safety assessment of the degree of embrittlement of subsequent reactor pressure vessels.

_{[0092] It} should be noted that, in the present invention, the scheme for obtaining the neutron irradiation flu by the formula ( ₃₎ is obtained by the inventor through repeated verification and exerting creative labor, and is an important invention of the present invention. First, no identical or similar solutions are disclosed in the prior art.

_[0093] Further, the safety evaluation process in step ₃₄ is: using the reactor pressure vessel steel neutron irradiation fluence 0 as an analysis input parameter, and irradiating the reactor pressure vessel according to the analysis input parameter Degree of security assessment.

_[0094] The technical solution of this embodiment has the following technical effects:

_{[0095] (1)} Real-time, online, continuous testing of resistivity of reactor pressure vessel steel during operation of nuclear power plant

And real-time calculation of the neutron radiation quantity data of the reactor pressure vessel steel;

_{[0096] (2)} Since the physical property test of the reactor pressure vessel steel is non-destructive, the data can be acquired indefinitely during the full life of the nuclear power plant, including during the future life extension operation;

_{[0097] (3) The} test equipment and operation do not require special radiation safety protection requirements, and there is basically no requirement for the external space of the equipment, and the cost is low and the safety is good, especially no radioactive waste is generated, and there is basically no need for three waste disposal;

_{[0098] (4) The} degree of irradiation embrittlement of the reactor pressure vessel can be monitored at the same time, and is particularly suitable for monitoring the initiation of microcracks or suspected microcracks found during the in-service inspection of the reactor pressure vessel during the overhaul of the nuclear power plant. Extended behavior.

_[0099] Embodiment 7:

_[0100] Referring to FIG. _{6, the} present invention also shows an apparatus for evaluating neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel, comprising:

_[0101] monitoring unit ₁ , evaluation unit ₂ and display unit _3;

_{[0102] The} monitoring unit _{1 is} connected at one end to a reactor pressure vessel for monitoring the resistivity of the reactor pressure vessel steel, and the other end is connected to the evaluation unit _2; wherein the resistivity of the reactor pressure vessel steel comprises: After the reactor pressure vessel is installed in place, and before the nuclear power plant is first charged, the initial resistivity of the reactor pressure vessel steel is measured, and during the normal operation of the nuclear power plant, real-time measurement Resistivity of the neutron irradiation embrittlement of the reactor pressure vessel steel at any point in time obtained

_{[0103] The} evaluation unit _{2 is} configured to calculate macroscopic mechanical properties of the reactor pressure vessel steel in irradiation embrittlement according to the detected resistivity p of the reactor pressure vessel steel, and according to the macroscopic mechanics Performance to perform a safety assessment of the degree of embrittlement damage of the reactor pressure vessel;

_[0104] and _/ or, calculating the neutron irradiation fluence of the reactor pressure vessel steel according to the detected resistivity of the reactor pressure vessel steel, and according to the reactor neutron irradiation fluence of the reactor pressure vessel steel The degree of irradiation embrittlement of the reactor pressure vessel is assessed for safety;

_{[0105] The} display unit _{3 is} connected to the evaluation unit ₂ for displaying a result of safety evaluation of the degree of irradiation embrittlement of the reactor pressure vessel according to the macroscopic mechanical properties and _/ or the neutron irradiation fluence .

_[0106] Specifically, the evaluation unit ₂ includes:

_{[0107] a} storage unit ₂₁ , configured to store a resistivity of the reactor pressure vessel steel detected by the monitoring unit;

_{[0108] a} calculating unit _22, configured to calculate _, according to the monitored resistivity of the reactor pressure vessel steel, macroscopic mechanical properties of the reactor pressure vessel steel during irradiation embrittlement; and _/ or The measured resistivity of the reactor pressure vessel steel is calculated to obtain the neutron irradiation fluence of the reactor pressure vessel steel; the calculation process is shown in formula ( ₁ )-( ₃ ), and will not be repeated here;

_[0109] and a judging unit _23, configured to perform safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to macroscopic mechanical properties and _/ or neutron irradiation fluence of the reactor pressure vessel steel, specifically, Presetting conditions may be set in the determining unit, and the macroscopic mechanical properties and _/ or the neutron irradiation fluence of the reactor pressure vessel steel are input as the analysis input parameter to the determining unit, and when the value of the input parameter is analyzed When the preset condition is met, the determining unit issues an early warning.

_{[0110] It} should be noted that the technical features in the first to third embodiments of the present invention may be arbitrarily combined, and the combined technical solutions are all within the protection scope of the present invention.

_0111] In summary, the present invention provides a method and apparatus for assessing reactor pressure vessel neutron irradiation embrittlement degree, which can be real-time, on-line, continuous testing resistivity of the reactor pressure vessel steel changes during operation of nuclear power plants, The macroscopic mechanical properties and _/ or neutron irradiation fluence data of the reactor pressure vessel steel are obtained in real time; since the physical properties (resistivity) test of the reactor pressure vessel steel is non-destructive, the full life of the nuclear power plant, including the future The data can be tested indefinitely during the life extension operation; the test equipment and operation do not require special radiation safety protection requirements, and there is basically no requirement for the external space of the equipment, and the cost is low. \¥0 2019/104510 卩(:17 \2017/113491

13 Safety is good, especially if no radioactive waste is generated, and there is basically no need for three waste treatment; and, macroscopic mechanical properties and/or neutron irradiation fluence at multiple locations of the reactor pressure vessel can be monitored simultaneously.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are included in the spirit and principles of the present invention, should be included in the present invention. Within the scope of protection of the invention.

Claims

\¥0 2019/104510 卩(:17€\2017/113491 14 Claims

[Claim 1] A method for evaluating the degree of neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel, characterized by comprising the steps of:

_81. Establish a benchmark: Measure the initial resistivity of the reactor pressure vessel steel _;

_52. Real-time monitoring: During the normal operation of the nuclear power plant, the resistivity of the neutron irradiation embrittlement of the reactor pressure vessel steel at any time point is obtained in real time^

_33. Analytical calculation: based on the initial resistivity and real-time obtained resistivity after irradiation embrittlement of the reactor pressure vessel steel ₍ > obtaining macroscopic mechanical properties of the reactor pressure vessel steel during irradiation embrittlement; And _/ or, the neutron irradiation fluence of the reactor pressure vessel steel;

4. Safety assessment: The degree of irradiation embrittlement of the reactor pressure vessel is evaluated based on the macroscopic mechanical properties and _/ or the reactor neutron irradiation fluence analysis of the pressure vessel steel.

[Claim 2] The method according to claim 1, wherein, in the step 32, the real-time access resistivity of the reactor pressure vessel steel at any point in time the same site neutron irradiation embrittlement _£>.

[Claim 3] The method according to claim 1, characterized in that the macroscopic mechanical properties of yield strength of real-time /? Ductile transition temperature and no real /? A at least 7 \ _^ in.

[Claim 4] The method according to claim 3, wherein, in step 33, the real-time yield strength of the reactor pressure vessel steel in the irradiation embrittlement is calculated according to the formulas (1 _)-(2) _. And at least one of the real-time non-ductile transition temperatures /? _^^ , wherein the formulas (1 _)-(2) are:

[Claim 5] The method according to claim ₄ , characterized in that, for a specific nuclear power plant and a reactor pressure vessel, said, , , ₈ , and ₆ can be tested for irradiation supervision samples by a conventional irradiation supervision method The mechanical properties data, as well as the initial resistivity of the reactor pressure vessel steel, are determined or corrected.

[Claim 6] The method according to any one of claims _3-4 , wherein the security review in step ₃₄ \¥0 2019/104510 卩(:17€\2017/113491

The estimation process is: using at least one of the real-time yield strength _/? and the real-time non-ductile transition temperature as an analysis input parameter, and the radiation embrittlement degree of the reactor pressure vessel is safe according to the analysis input parameter. Evaluation.

[Claim 7] The method according to claim ₁ , wherein in step ₃₃ , the neutron irradiation fluence of the reactor pressure vessel steel is calculated based on formula ( ₃ ), and the formula ( ₃ ) is:

0=8 _{3+6 3} . ^>+ () ² (3) ;

Wherein, the neutron irradiation fluence of the reactor pressure vessel steel; , : ₈ , (: are proportional factors.

[Claim 8] The method according to claim ₇ , characterized in that, for a specific nuclear power plant and reactor pressure vessel, said: ₈ , (: irradiation fluence data obtainable by a conventional irradiation supervision method , and the initial resistivity of the reactor pressure vessel steel is determined or corrected.

[Claim 9] The method according to any one of claims _7-8 , wherein the safety evaluation process in step ₃₄ is: using the reactor neutron irradiation fluence of the pressure vessel steel as an input parameter for analysis, A safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel is performed based on the analytical input parameters.

[Claim 10] The method according to claim ₁ , wherein, in the step, the initial resistivity

The measurement process of ^^ is: After the reactor pressure vessel is installed in place, and before the first charge operation of the nuclear power plant, the initial resistivity of the reactor pressure vessel steel is measured.

[Claim 11] The method according to claim _1, wherein the radiation brittleness of the reactor pressure vessel is evaluated according to the macroscopic mechanical properties and _/ or the reactor neutron irradiation fluence analysis of the pressure vessel steel The degree of progress includes: setting a preset condition to issue an early warning when the macroscopic mechanical properties and _/ or the reactor neutron irradiation fluence of the reactor pressure vessel meets the predetermined condition.

[Claim 12] An apparatus for evaluating the degree of neutron irradiation embrittlement in a nuclear power plant reactor pressure vessel,

The utility model is characterized in that it comprises: a monitoring unit and an evaluation unit; the monitoring unit is connected at one end to the reactor pressure vessel for monitoring the resistivity of the reactor pressure vessel steel, and the other end is connected to the evaluation unit;

The evaluation unit is configured to calculate the resistivity of the reactor pressure vessel steel according to the monitoring \¥0 2019/104510 卩(:17 \2017/113491

16 obtaining macroscopic mechanical properties of the reactor pressure vessel steel during irradiation embrittlement, and performing safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to the change of the macroscopic mechanical properties;

And/or calculating a neutron irradiation fluence of the reactor pressure vessel steel according to the measured resistivity of the reactor pressure vessel steel, and according to the change of the neutron irradiation fluence of the reactor pressure vessel steel The degree of irradiation embrittlement of the reactor pressure vessel is evaluated for safety.

[Claim 13] The apparatus according to claim 12, wherein the evaluation unit comprises:

a storage unit, configured to store a resistivity of the reactor pressure vessel steel monitored by the monitoring unit; and a calculating unit configured to calculate a reactor pressure vessel steel in the irradiation brittle according to the monitored resistivity of the reactor pressure vessel steel Macroscopic mechanical properties during the process; and/or for calculating the neutron irradiation fluence of the reactor pressure vessel steel based on the monitored resistivity of the reactor pressure vessel steel;

And a judging unit for performing a safety assessment on the degree of irradiation embrittlement of the reactor pressure vessel according to the calculated macroscopic mechanical properties of the reactor pressure vessel steel during the irradiation embrittlement process; and/or The degree of irradiation embrittlement of the reactor pressure vessel is evaluated safely based on changes in the neutron irradiation fluence of the reactor pressure vessel steel.

[Claim 14] The device according to any one of claims 12 to 13, further comprising a display unit

The display unit is connected to the evaluation unit for displaying a result of safety evaluation of the degree of irradiation embrittlement of the reactor pressure vessel according to the macroscopic mechanical property, and/or according to the reactor pressure vessel steel The results of a safety assessment of the degree of irradiation embrittlement of the reactor pressure vessel by the sub-irradiation fluence.