JPH05333189A - Remaining life estimating method for material exposed to radiation environment and its device - Google Patents

Abstract

(57) [Summary] [Object] To provide a residual life estimation apparatus and method applicable to a nuclear reactor capable of measuring the residual life by simply measuring the physical characteristics of a sample. [Structure] A real sample having substantially the same composition is placed in a life monitoring part for monitoring the life, and a measuring means for measuring a physical characteristic value of the real sample and the environment of the model sample previously obtained by an experiment Storage means for storing the relationship between the elapsed time and the physical property value, means for storing the life time of the elapsed time until the unstable destruction of the model sample in the environment obtained in advance by experiment, and the actual sample And means for calculating the remaining life from the difference between the elapsed time corresponding to the measurement result and the time stored in the life time storage means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for estimating the remaining life of a material exposed to high energy particles or electromagnetic waves, and is particularly suitable for a metal material which is used under high temperature water / neutron irradiation and causes stress corrosion cracking. Remaining life estimation method and apparatus.

[0002]

2. Description of the Related Art Materials such as austenitic stainless steel used in a nuclear reactor are exposed to radiation under the corrosive environment of high temperature water, so that irradiation-induced stress caused by corrosion damage or material change is caused. Corrosion cracking (IASCC) may occur. Irradiation-induced stress corrosion cracking (SCC) is classified into intragranular type and grain boundary type according to the shape of the fracture surface.

In these nuclear reactor plants, if an accident should occur, its social ripple effect is great, and therefore it is essential to prevent the accident. As a method of suppressing irradiation-induced stress corrosion cracking (IASCC), a method of injecting hydrogen is currently proposed. In this method, the dissolved oxygen concentration is reduced by injecting hydrogen,
Or reduce the corrosion potential.

Conventionally, the safety against stress corrosion cracking of the above materials has been confirmed by carrying out a periodic inspection every year, and a guarantee for use after the periodic inspection is provided. However, with this method, although the safety at the time of regular inspection can be confirmed, it is not possible to predict the life whether or not stress corrosion cracking will occur before the next periodic inspection.

Further, as a stress corrosion cracking life diagnosis system for metal materials, there is a technique described in JP-A-64-69942. This technique evaluates stress corrosion cracking characteristics by determining the amount of electric charge for active dissolution of the new surface and the localization coefficient of corrosion.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the technique described in Japanese Patent No. 942, in order to measure the remaining life of the sample, it is necessary to obtain the charge amount and the localization coefficient of corrosion for the active dissolution of the new surface. Therefore, there is a problem that it is not possible to measure the remaining life of a material which is embrittled by irradiation of particles, by only performing a simple inspection on the sample.

It is an object of the present invention to measure the remaining life of a material that can undergo unstable fracture by exposure to energetic particles or electromagnetic waves by simply measuring the physical properties of the sample. Another object of the present invention is to provide a residual life estimation apparatus and method applicable to a nuclear reactor.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a material whose mechanical properties are deteriorated by being exposed to high energy radiation is exposed under a plurality of exposure conditions. The first step to find the relationship between the physical quantity of multiple types of model samples obtained by exposure to high-energy radiation and the exposure period. From the relationship obtained in the first step, the criticality leading to unstable destruction of the sample The second step of obtaining the exposure period, the third step of installing an actual sample made of a material having substantially the same composition as the model sample under the high-energy radiation irradiation environment of the measurement target containing the material as a constituent member From the relationship between the exposure step and the physical quantity obtained in the first step, the physical quantity of the real sample obtained in the fourth step is compared with the physical quantity of the real sample obtained after the irradiation. And the actual exposure period of the measurement target, and the difference between the critical exposure period of the second step and the actual exposure period of the measurement target of the fourth step. A remaining life estimation method is provided including the steps of.

The first step comprises the first step of obtaining the relationship between the physical quantity of a plurality of types of model samples and the exposure amount, and the exposure amount and the exposure period of the measurement object corresponding to the exposure amount. A first two steps of determining the relationship,
In the second step, a critical embrittlement amount that causes unstable fracture of the material and a critical exposure amount corresponding to the critical embrittlement amount are obtained from the relationship obtained in the first step.
The second step of obtaining the relationship between the critical exposure period of the measurement target corresponding to the critical exposure amount from the relationship between the exposure amount and the exposure healing period obtained in the first step of It is possible to include.

Further, according to the second aspect of the present invention, a plurality of types of materials obtained by exposing a material, whose mechanical properties are deteriorated by being exposed to high energy radiation, to high energy radiation under a plurality of exposure conditions. First storage means for storing the relationship between the physical quantity of the sample and the exposure period obtained based on the model sample, and the relationship stored in the first storage means causes the material to undergo unstable destruction by irradiation. First calculation means for determining a critical exposure period, the composition is installed under a high-energy radiation irradiation environment of a measurement target including substantially the same material as the model sample as a constituent member, and has substantially the same composition as the model sample Means for taking in a physical quantity after irradiation obtained from an actual sample made of a material having a substance, and the object of the actual sample taken in by the taking means from the relationship between the physical quantity stored in the first storage means and the exposure time. A means for determining an actual exposure period corresponding to the amount, using this as the actual exposure period of the measurement target, and means for determining a difference between the actual exposure period of the measurement target and the critical exposure period determined by the first calculation means. A life estimation device is provided.

The first storage means is a first first storage means for storing the relationship between the physical quantities of a plurality of types of model samples and the exposure quantity, and the exposure quantity and the exposure of the measurement object corresponding to the exposure quantity. A second storage means for storing a relationship with a period, wherein the first computing means has a critical brittleness which causes unstable fracture of the material due to the relationship stored in the first first storage means. Using the relation stored in the first first calculating means for determining the amount of oxidization and the critical exposure amount corresponding to the critical embrittlement amount, and the first second storage means, the measurement corresponding to the critical exposure amount. A first second calculating means for obtaining the relationship between the critical exposure period of the object can be provided.

[0012]

In the remaining life estimation method according to the first aspect of the present invention, the actual sample includes a material having substantially the same composition as that of the lifespan monitoring section for monitoring the lifespan, and substantially the lifespan monitoring section. Are placed under high-energy radiation in the same environment.

Here, high energy radiation refers to high energy particles such as neutrons, ions, α rays, γ rays and electromagnetic waves. In the present invention, high-energy particles and electromagnetic waves having an energy that causes embrittlement of a metal material at 0.1 MeV or more are referred to as high-energy radiation.

Further, as an experiment, a plurality of types of model samples are arranged in substantially the same environment as the life monitoring part, and the exposure period under the environment and the physical quantity of the model sample are measured. Thus, the relationship between the exposure period under the environment and the physical quantity of the model sample is obtained. From the relationship between the exposure period of the model sample and the physical quantity, the critical exposure period until the unstable destruction of the material forming the actual sample is caused is obtained. In the present invention, unstable fracture is stress corrosion cracking or cracking that occurs in an actual sample placed in a life monitoring unit under irradiation of high-energy radiation, and the cracks grow and grow,
It indicates the state of instantaneous fracture, and includes both brittle fracture and ductile fracture.

Next, the physical quantity of the actual sample placed in substantially the same environment as the life monitoring section is measured at any time.

Using the relationship between the physical quantity and the exposure period, the relationship between the physical quantity corresponding to the physical quantity of the actual sample and the exposure period is obtained. Next, the difference between the physical quantity of the actual sample and the critical exposure period is calculated and used as the remaining life of the life monitoring part.

The physical quantity is compliance, hardness,
Mechanical properties such as strength and elongation and stress corrosion cracking properties can be used.

The method and apparatus for estimating the remaining life of the present invention is suitable for estimating the remaining life of materials used in fusion reactors, nuclear reactors, particle accelerators and the like.

[0019]

An embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1) As shown in FIG. 17, the apparatus for estimating the remaining life of the austenitic stainless steel of the reactor constituent member of the first embodiment of the present invention uses the compliance λ as the physical quantity of the sample 11 shown in FIG. Measuring device 14 for measurement
And a storage device 112 that stores a function g that represents the relationship between the compliance λ of the sample 11 and the elapsed time t, and the elapsed time tc until the sample 11 reaches the end of life, obtained by experiments in advance, and the measuring device 14. Measurement results and storage device 11
An arithmetic unit 19 for calculating the remaining life using the stored contents of No. 2. Further, a display device 10 for displaying the remaining life,
A function compensating device 111 for compensating the function g of the stored contents of the memory device 112 and a timer 113 for outputting an elapsed time t _o used for compensation are configured. In this example,
The elapsed time t corresponds to the above-mentioned exposure period. In addition, the elapsed time t _c until reaching the end of life corresponds to the critical exposure period until the above-mentioned unstable breakdown occurs.

As shown in FIG. 15, the measuring device 14 uses the sample 1
1, a pulling jig 18 connected to the sample 11 for pulling the sample 11, and a state in which a constant displacement Φ is applied to the sample 11,
The screw 16 for fixing the pulling jig 18 to the restraining jig 15 is provided. A load cell 13 for measuring a tensile load p applied to the sample 11 and converting the tensile load p into an electric signal is connected to the pulling jig 18. The load cell 13 is
The one having an allowable maximum load of 500 kg and an accuracy of ± 1 kg, which can be used in high-temperature high-pressure water of 370 ° C. or less and 150 atm or less subjected to radiation irradiation, was used.

In this embodiment, the sample 11 is used as the model sample and the actual sample. Sample 11 is made of austenitic stainless steel having the same composition as the reactor constituent member whose life is to be measured, and has a plate thickness B of about 5 m as shown in FIG.
m, width W = about 12 mm, and has through holes 11a and 11b for connecting to the pulling jig 18. Further, between the through holes 11a and 11b, a notch 11c having a width Φ ₀ of the opening when a load is not applied is provided. In addition, about 1.5 at the tip of the notch 11c.
A fatigue precrack 12 having a length of mm is provided. The fatigue pre-crack 12 is based on the standard (ASTM E-399), the through holes 11a and 11b of the sample 11 are connected to a tensile tester, and the fracture toughness value of the constituent material of the sample 11 is 60 at room temperature atmosphere. The stress intensity factor value of% or less is shown in FIG.
It was provided by pulling in the direction of the arrow. As a result, the tip of the fatigue pre-crack 12 is about 1 / the width W of the sample 11.
Reached position 2. The fatigue precrack 12 is provided equally when the sample 11 is used as a model sample and when it is used as an actual sample.

The sample 11 provided with the fatigue pre-crack 12 was directly connected to the pulling jig 18 and the internal load cell 13, and this was tested by a tensile tester until the opening of the notch 11c became a constant displacement Φ. Pull. Then, the sample 11 is set in the measuring device 14 by fixing these to the restraining jig 15 with the screws 16 in a pulled state.

As shown in FIGS. 17 and 16, the measuring device 14 equipped with the sample 11 as an actual sample is shown in FIG.
It is arranged inside the neutron instrumentation tube 170. In this embodiment, the measuring device 14 is loaded into the reactor from the beginning of operation of the reactor. The neutron instrumentation tube 170 has a wall thickness of about 1.5 mm, which is sufficiently smaller than the in-metal penetration ability of tens of centimeters of neutron irradiation, so that neutron irradiation and direct irradiation in the instrumentation tube 170 are: There is almost no difference, and the environment is almost the same as the reactor components. The signal line of the load cell 13 runs around the inside of the neutron instrumentation pipe 170, goes out of the reactor 17, and is connected to the arithmetic unit 19.

Next, the structure of the storage device 112 will be described.
As shown in FIG. 23, the storage device 112 includes the first storage means 11
It has 2a and the 2nd memory | storage means 112b. The first storage means 112a stores a mathematical formula of a function λ = g1 (a) indicating a relationship between the compliance λ of the sample 11 and the crack length a of the sample, which is previously obtained by an experiment using a plurality of model samples. ing. A graph of the function λ = g1 (a) is shown in FIG. In the second storage means 112b, the crack length a of the sample 11 and the elapsed time t after being placed in the reactor are also obtained by an experiment in which a plurality of model samples are similarly placed in a simulated reactor environment. The mathematical expression of the function a = g2 (t) indicating the relationship of and the time tc until the austenitic stainless steel reaches unstable life due to unstable fracture are stored. Function a
= G2 (t) and the time tc until reaching the end of life are shown in the graph of FIG.

The function g1 is as shown in FIG.
As shown in FIG. 5, it was obtained by using a plurality of samples 11 having different crack lengths and determining the relationship between the load p and the displacement Φ of these samples 11. Application to the reactor operating temperature of 288 ° C
It was performed by Young's modulus correction. Function g2, life t
_c is a simulated reactor environment (288 ° C, 8
0 atmospheric pressure high temperature high pressure water, gamma rays 10 ⁵ to 10 ⁸ R / H irradiation),
The measuring device 14 equipped with the sample 11 as a model sample is arranged, and the change in the load time P resulting from the time t after the arrangement and the crack growth is converted into the crack length a from FIG. 19 and obtained. It is a thing. Under this environment, the preformed crack gradually and stably progresses with the lapse of time t, and the length a thereof gradually increases. The crack length a was measured by actually confirming the tip of the crack with a microscope at regular time intervals.

The compliance λ of the sample 11 is
It measured as follows. Compliance λ is λ = EB
Φ / p (E: Young's modulus, B: thickness of sample 11). In FIG. 18, the crack length a is different (a _{1 to} a _{5 in the} figure).
It is the relationship between the load P and the crack opening displacement Φ within the elastic range obtained for the five samples 11. As shown in FIG. 18, it can be seen that the slope of the straight line decreases as the crack length increases. Compliance λ is shown in FIG.
Is the value obtained by multiplying the reciprocal of the gradient (Φ / P) by Young's modulus E and the thickness B of the test piece and standardizing. The measuring device 14 of the present embodiment is
The opening displacement of the sample 11 is maintained at a constant displacement Φ, and the load p applied to the sample 11 at this time is obtained as the output load p of the load cell 13. Therefore, Φ is given as a constant,
By measuring only the load p, the compliance λ
Got. This compliance λ and the crack length a are expressed in a graph as shown in FIG. 19, and a mathematical expression expressing the function λ = g1 (a) is obtained. As shown in FIG. 19, as the crack length a progresses, the load p decreases and the compliance λ increases.

Also, the elapsed time t was measured separately, and the relationship with the corresponding crack length a is shown in a graph as shown in FIG.
A mathematical expression expressing the function a = g2 (t) was obtained. The crack length a is
The stress intensity factor K of the material forming the sample 11 becomes larger.
Value, the fracture toughness value Kic of the material, at a time point q, the crack rapidly expands and the sample 11 breaks. The experiment under the simulated reactor environment is continued until the sample 11 which is a model sample breaks due to unstable fracture, and the elapsed time t _c to the point q at the time of fracture is obtained and this is the life. The elapsed time was tc.

These g1, g2 and tc are stored in the storage device 112.
I memorized it. The functions g1 and g2 are expressed by the formula g1 = k1a ⁵ + k2a ⁴ + k3a obtained by reading FIGS. 19 and 20, respectively.
³ + k4a ² + k5a + k6 (k1 to k6 are constants), g2
^{= M1t 5 + m2t 4 + m3t} 3 + m4t 2 + m5t + m6
(M1 to m6 are constants). Moreover, the measurement detection limit of the crack length a was ± 0.01 mm. The precrack length is 1/2 · W = 6 mm, so the crack length a
= 6.02 mm or less is the detection limit, and the remaining life predictable range is the range shown in FIG.

Next, the configuration of the arithmetic unit 19 will be described. The arithmetic unit 19 includes a first arithmetic unit 19a and a second arithmetic unit 19b. The first calculation means 19a is
The load p measured by the measuring means 14 which reads the function g1 of the first storage means 112a and mounts the sample 11 as an actual sample.
Substitute _o into the function g1. Λ _o = E obtained by this
From BΦ / p _o = g1 (a _f ), a _f corresponding to the load p _o is obtained and output to the second computing means 19b. Second computing means 1
9b reads the function g2 of the second storage means 112b,
The crack length a _f input from the first calculating means 19b is substituted into the function g2. A _f = g2 obtained by this
From (t _f ), t _f corresponding to the crack length a _f is obtained. Further, the second calculation means 19b reads the elapsed time t _c until the end of life from the second storage means 112b and calculates the remaining life t _c −t.
_f is calculated and output to the display device 10. Still further, the second calculation means 19b from the data a _f obtained so far, the time change rate da _f / dt _f of a _f, the stress intensity factor K
= Fσ√a = f · po / WB · √a (here, f; shape factor given in advance, σ; stress, a; crack length) is calculated and output to the display device 10.

Next, the structure of the function compensator 111 will be described. The function compensator 111 includes compensation calculation means 111.
a and a program storage unit 111b that stores a least squares method program. The function compensator 111 uses a _f
The time t _o when p _o measurements corresponding to, and received from the timer 113, the second calculation means, to calculate the a _o corresponding to the time t _o from the function g2. The function compensator 111 uses the function a =
(a _f , t _f ) obtained from g2 (t) is compared with a _f and a _{o of} (a _o , t _o ), which is calculated back from the actual time lapse t _o . When the difference between a _f and a _o is larger than a predetermined value, the least squares program is read from the program storage unit 111b. Then, a plurality of data (a _f n, t _o n) obtained so far (n: the number indicating the order of data),
(A _c , t _c ) and the function g2 is fitted by the least-squares method, and g2 is a different function a _f = g2 ′.
Compensate for (t _o ). (A _c , t _c ) is used so that a _c = g2 (t _c ) corresponding to the life time t _c is fixed so that the function g2 ′ satisfies a _c = g2 ′ (t _c ). This is because

The display device 10 includes a CRT 10a,
It has a printer 10b. CRT10a displays the remaining lifetime tc-tf, and the stress intensity factor K, and a time change rate da _f / dt _f of a _f. The printer 10b prints out these on paper.

Next, the operation of the remaining life measuring apparatus for the austenitic stainless steel constituting the nuclear reactor of this embodiment will be described with reference to the flowchart of FIG.

The measuring device 14 comprises the load cell 13
The load p _o applied to the sample 11, which is an actual sample, is measured and output to the arithmetic unit 19 (step 181). Arithmetic device 19
The first calculation means 19a of the above receives the load p _o and uses the function g1 of the first storage means 112a of the storage device 112 to obtain p
A crack length a _f corresponding to _o is obtained (step 182).
The crack length a _f is the crack measurement limit X ₀ = 0.
If it is larger than 02 mm, a _f is output to the second calculation means 19b, and if it is smaller, the process returns to step 181 (step 183).

The function compensator 111 outputs p _o corresponding to a _f.
The time t _o at the time of measurement is received from the timer 113, is output to the second calculating means, and the second calculating means 19b receives the function g.
2, to calculate the a _o corresponding to the time t _o (step 184). Then, the function compensator 111 compares a _f and a _o (step 185). If the difference is larger than a predetermined value, the function g2 is calculated using the least square method as described above.
To the function g2 ′ (step 186). The second arithmetic unit 19b obtains the time t _f corresponding to a _f using the compensated function g2 in the second storage means 112b. Furthermore, the elapsed time t that is the life of the second storage means 112b.
_{From c} , t _c −t _f is calculated and this is output to the display device 10 as the remaining life. Furthermore, the second computing means 19
b is the time change rate da _{f of} a _f from the data obtained so far.
/ Dt _f and stress intensity factor K _f = Fσ√a _f = F · p _o / W
B√a _f (where F: shape factor, σ; stress, a _f ; crack length) is calculated and output to the display device 10 (step 187). Display device 10 includes a remaining life (t _c -t _f), and displays the stress intensity factor K _f, the da _f / dt _f (step 188).

As described above, the remaining life measuring apparatus of this embodiment is
As a real sample, a sample 11 having a pre-crack was placed in almost the same environment of the nuclear reactor and its load was measured with a simple configuration, and an unstable fracture of the austenitic stainless steel of the nuclear reactor component against stress corrosion cracking Life expectancy against
It can be easily and accurately measured. Normally, a structure is used under a stress condition that does not cause crack growth (a stress condition of a crack generation limit stress intensity factor K _th or less in FIG. 21), but a crack is generated and propagates starting from a welding defect or inclusion. There is. The generated crack gradually and stably progresses with time, but when the crack length becomes large and the K value becomes equal to the fracture toughness value K _ic of a known material, the crack rapidly progresses as shown in FIGS. 20 and 21. Elongates and breaks due to unstable fracture. The residual life measuring apparatus of the present embodiment causes such a crack development on the sample 11 of the actual sample in the environment of the actual furnace, and by using the mechanical characteristic value of the sample 11, the simulation is performed with high accuracy. , To measure the remaining life.

In the present invention, the compliance λ of the sample 11 is used as a variable, and this is measured by the measuring device 14 which gives the sample 11 a constant displacement Φ. As a result, it is only necessary to measure the load p applied to the sample 11, and it is possible to perform actual measurement within the nuclear reactor under severe environmental conditions. Further, the function compensator 111 corrects the function g2, which is a known crack growth curve, when the measured crack length is significantly different. This makes it possible to accurately predict the service life. Further, in the above, the function compensation device 111
22 has described the operation of performing steps 184 to 186 in each measurement, but it is not always necessary to perform each measurement, and it is of course possible to perform the operation once in several times at an arbitrary time interval. is there. Also, the fracture toughness value K _ic
Can have a safety factor (margin).

In the present invention, the crack length a measured above and the crack growth rate da _f / dt _f calculated from the life prediction apparatus are used.
And the stress intensity factor K is displayed on a device such as a display or a printer so that the crack growth behavior of the material in the furnace can be confirmed at a glance. Therefore, it is a very useful remaining life measuring device.

Also, in the first embodiment, the storage device 112.
The functions to be stored in λ = g1 (a) and a = g2 (t)
Then, the crack length a was once determined and constructed. Here, since it can be expressed as λ = g1 · g2 (t) = g (t), it is of course possible to obtain the remaining life directly from the elapsed time t with one function g.

Further, in this embodiment, the sample 11 having the same composition as that of the part for monitoring the life was used. However, if the relationship between the part for monitoring the life and the change in mechanical characteristics with time of the sample 11 is clear in advance. It is also possible to form the sample 11 with materials having different compositions. Further, in this embodiment, the measuring device 14
Was placed inside the neutron instrumentation pipe 170. However, even if the environment around the neutron instrumentation pipe 170 is different from the environment, the difference in the remaining life due to the difference in the environment is clear. If so, the life can be monitored. In these cases, the calculation means corrects the difference in the remaining life.

Further, in this embodiment, as the model sample,
Although the sample 11 having the same shape as the actual sample was used, the sample is not limited to this. Model samples of various shapes can be used as long as the relationship between the exposure period and the compliance λ can be obtained.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a remaining life measuring apparatus according to this embodiment, and FIG. 2 is a flowchart of a remaining life measuring method according to this embodiment.

As shown in FIG. 1, this residual life measuring apparatus comprises an input means such as a keyboard 1 for inputting the amount of change in mechanical characteristic value of a real sample irradiated with high energy particles such as neutrons or electromagnetic waves. A storage unit 3 that stores predetermined information in advance, a calculation unit 2 that performs a predetermined calculation according to a program written in a memory (not shown), and a calculation unit 3
And an output unit such as a CRT 4 for displaying the remaining life output from the device.

The storage unit 3 stores the amount of change in mechanical characteristic values of several model samples irradiated with a predetermined amount of particles, and the irradiation embrittlement amount indicating the degree of embrittlement of the model sample due to particle irradiation. The first storage means that stores the relationship between the model sample, the relationship between the particle irradiation amount to the model sample and the irradiation embrittlement amount of the model sample, and the criticality at which fracture due to stress corrosion cracking of the model sample occurs. A second storage unit that stores in advance a critical irradiation amount that is an irradiation amount corresponding to the irradiation embrittlement amount, a particle irradiation amount of an actual sample having substantially the same composition as the model sample, and particles of the actual sample. It is configured to include a third storage unit that stores the relationship with the irradiation period in advance.

The contents stored in the storage unit 3 will be described with reference to FIG. FIG. 3 is a graph showing the contents stored in the storage unit 3. FIG. 3A shows the first
7 is a graph showing the contents of the storage means, in which the vertical axis represents the amount of change in mechanical property value and the horizontal axis represents the amount of irradiation embrittlement. The amount of change in mechanical property value on the vertical axis refers to, for example, the amount of change in hardness before and after irradiation of particles such as ions and neutrons, the amount of increase in 0.2% proof stress, and the like. The irradiation embrittlement amount shown on the horizontal axis represents the amount of embrittlement due to unstable fracture described above, and the embrittlement due to brittle fracture of the sample,
Includes embrittlement due to ductile fracture. Specifically, it refers to a ratio of break elongation before and after particle irradiation (break elongation after particle irradiation / break elongation before particle irradiation).

FIG. 3B is a graph showing the contents of the second storage means, in which the vertical axis represents the particle irradiation amount to the model sample and the horizontal axis represents the irradiation embrittlement amount. The critical irradiation embrittlement dose shown in the same figure refers to the irradiation embrittlement dose when a crack occurs, and the particle irradiation dose corresponding to this critical irradiation embrittlement dose is referred to as the critical particle irradiation dose.

FIG. 3C is a graph showing the contents of the third storage means, where the vertical axis represents the particle irradiation amount of the actual sample and the horizontal axis represents the particle irradiation period. Here, the particle irradiation critical period refers to a particle irradiation period corresponding to the critical particle irradiation amount.

The contents of FIGS. 3 (a), 3 (b) and 3 (c) described above may be displayed on an output means such as a CRT 4 if necessary.

The calculation unit 2 is composed of a CPU, and first calculation means for obtaining the irradiation embrittlement amount corresponding to the change amount of the mechanical property value of the actual sample irradiated with particles from the first storage means, and the first calculation. A second calculation means for obtaining, from the second storage means, the particle irradiation amount to the actual sample corresponding to the irradiation embrittlement amount obtained from the means, and the particle irradiation amount to the actual sample obtained from the second calculation means. A third calculation means for obtaining the particle irradiation period of the actual sample from the third storage means, and a critical irradiation period corresponding to the critical irradiation amount stored in the second storage means are obtained from the third storage means, and this critical irradiation is carried out. Compare the period and the particle irradiation period,
A fourth calculation means for calculating either or both of the difference and the ratio is provided.

Next, a method of measuring the remaining life of a material using this remaining life measuring apparatus 100 will be described. Generally, a material undergoes changes in hardness, strength and elongation when irradiated with particles such as neutrons. On the other hand, along with such a material change, the material becomes brittle by irradiation. Therefore, in order to measure the remaining life of the material, the relationship between the amount of change in mechanical properties such as hardness and strength and the amount of irradiation embrittlement is obtained for the material irradiated with particles such as neutrons. Further, the relationship between the irradiation embrittlement amount and the particle irradiation amount and the relationship between the particle irradiation period and the particle irradiation amount are obtained. Then, the amount of irradiation embrittlement was determined from changes in mechanical properties such as hardness and strength, and the remaining life was measured.

This method will be described with reference to the flowchart shown in FIG. First, the amount of change in the mechanical characteristic value of the actual sample irradiated with the particles is input (step 41). next,
From the first storage means that stores the relationship between the amount of change in mechanical properties and the irradiation embrittlement amount of the model sample that has been irradiated with a predetermined amount of particles and has substantially the same composition as the actual sample, An irradiation embrittlement amount corresponding to the mechanical characteristic value change amount is obtained (step 42). As described above, the irradiation embrittlement amount indicates the embrittlement amount due to unstable fracture. Next, the relationship between the particle irradiation amount to the model sample and the irradiation embrittlement amount of the model sample, and the critical irradiation amount that is the irradiation amount corresponding to the critical irradiation embrittlement amount at which the model sample fractures are stored in advance. The amount of particle irradiation to the actual sample corresponding to the irradiation embrittlement amount of the actual sample is obtained from the second storage means (step 43). Next, the particle irradiation dose to the actual sample is
When the dose is above the critical dose (step 44), that fact is output, and material replacement and the like are displayed (step 45). Further, when the particle irradiation amount to the actual sample is less than the critical irradiation amount, the relationship between the particle irradiation amount to the actual sample and the particle irradiation period to the actual sample is stored in advance from the third storage means, A particle irradiation period corresponding to the particle irradiation amount of the actual sample which has been irradiated with particles is obtained (step 46). Next, either or both of the difference and the ratio between the particle irradiation period and the particle irradiation critical period corresponding to the critical irradiation amount are obtained (step 47),
The remaining life is output to the CRT or the like (step 48).

Since the above processing is performed by using the remaining life measuring apparatus 100 according to this embodiment, the operator inputs the mechanical characteristic value change amount of the actual sample into this remaining life measuring apparatus 100. As a result, it is possible to know the remaining life of the structure made of the same material as this actual sample. The amount of change in mechanical property value means a difference or ratio of 0.2% proof stress, hardness, elongation at break and tensile elongation before and after particle irradiation. Further, instead of the change amount of the mechanical characteristic value, the change amount of the electric characteristic value such as the difference between the electric resistance before and after the irradiation and the eddy current may be input.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to FIGS. 4, 5, 6, 7, 8, 9, 10, 11, 12.
Will be explained.

The present embodiment is an example of measuring the remaining life of a material which undergoes neutron irradiation in a nuclear reactor and causes stress corrosion cracking. When neutrons collide with atoms in a metal, a large number of irradiation defects (point defects) are formed by a cascade process. They move and disappear in a short time within about 10 to ³ seconds in the cascade, and the number reaches a certain value. The point defects that survive within each of these cascades travel long distances to form secondary defects such as dislocations and voids, which increase the resistance to dislocation motion, causing embrittlement and hardening.

On the other hand, the interstitial atoms and vacancies formed in the material by irradiation interact with the solute atoms, and P, S
It causes segregation of chemical components such as i, Cr, Ni and Mn. This affects the material's susceptibility to stress corrosion cracking.

As described above, when a material, particularly a metal material, is subjected to neutron irradiation, the mechanical properties such as irradiation embrittlement and hardening change, and the stress corrosion cracking susceptibility changes. Therefore, if the relationship between the two is obtained, the stress corrosion cracking characteristics can be determined from changes in hardness, strength and elongation.

For a model sample having the same composition as the austenitic stainless steel used as a reactor material, after neutron irradiation, high strain water (288 ° C.) was obtained by a low strain rate (about 10 to ⁷ S to ¹ ) tensile test (sert test). , 85 bar, 32p
As a result of investigating the relationship between the stress corrosion cracking property and the elongation at break (elongation until break) in pmDO), it was found that there is a relationship shown in FIG. In this example, the model sample is broken by unstable fracture including brittle fracture and ductile fracture. FIG. 12 shows the irradiation embrittlement and the grain boundary stress corrosion crack fracture of the austenitic stainless steel subjected to neutron irradiation, which was determined by the ratio of the break elongation before and after irradiation (break elongation after irradiation / break elongation before irradiation). It is a graph showing the relationship with the surface ratio, showing the ratio of break elongation before and after irradiation on the horizontal axis,
The vertical axis shows the grain boundary type stress corrosion cracking fracture rate. The circles are the results for the SUS304-based material, and the triangles are the results for the SUS316-based material.

As shown in FIG. 12, as the decrease in fracture elongation due to neutron irradiation increases, the grain boundary type stress corrosion cracking fracture surface ratio increases, and when the irradiation embrittlement amount is large, the stress corrosion cracking resistance also deteriorates. It is suggested that In addition, it was found that grain boundary type stress corrosion cracking did not occur when the ratio of fracture elongation before neutron irradiation and after neutron irradiation was about 60% or more,
It was found that there is a limit of irradiation embrittlement that does not cause intergranular stress corrosion cracking. In addition, this result shows that there is no difference between the neutron irradiation in the reactor and the particle irradiation by the ion accelerator shown in FIG. 11 described later, and the materials in the reactor can be evaluated by experiments using the accelerator. I understand. This model sample has a plate width of about 3 mm and a length of about 1 mm.
The thickness is 5 mm and the plate thickness is about 0.3 mm.

In this embodiment, an actual sample having the same shape and composition as the model sample is loaded into the reactor from the beginning of operation. Regarding the loading position of the actual sample in the reactor, see Figs.
Will be explained. FIG. 7 is a sectional view showing a neutron instrumentation tube for loading an actual sample. FIG. 8 is a graph showing the intensity distribution of the neutron irradiation dose in the axial direction of the neutron instrumentation tube, the vertical axis is the length of the neutron instrumentation tube (total length about 4 m), and the horizontal axis is the neutron irradiation intensity.

The actual sample is loaded in the neutron instrumentation tube 170 as shown in FIG. This neutron instrumentation tube 170
A fluence monitor 171, which measures neutron flux, a spacer 172, a tensile test piece assembly loading position 173 for loading a tensile test piece assembly, and a hardness sample assembly loading position 173 for loading a hardness test piece assembly And is configured. This neutron instrumentation tube 170 has a wall thickness of about 1.5 mm, which is sufficiently smaller than 10 cm, which is the penetration capability of neutron irradiation in metal, so that neutron irradiation and direct irradiation in the instrumentation tube are almost the same. There is no difference. The two sample pieces 173 and 174 are loaded into the sample insert section 180 having a neutron irradiation intensity distribution as shown in FIG.

Next, the remaining life measuring apparatus according to this embodiment will be described with reference to FIG. FIG. 4 is a block diagram of the remaining life measuring apparatus according to the present embodiment. As shown in FIG. 4, this remaining life measuring apparatus is a keyboard 1 for inputting the amount of change in mechanical characteristic value of an actual sample irradiated with neutrons in a nuclear reactor.
And the like, a storage unit 70 that stores predetermined information in advance, and a calculation unit 6 including a CPU that performs a predetermined calculation according to a program written in a memory (not shown).
0 and an output means such as a CRT 4 for displaying the remaining life.

The storage unit 70 stores in advance the relationship between the change amount of the mechanical characteristic value of the model sample irradiated with a predetermined amount of ions and the irradiation embrittlement amount indicating the degree of embrittlement. And second storage means for storing in advance the relationship between the stress corrosion cracking susceptibility of the model sample and the irradiation embrittlement amount of the sample, and the ion irradiation amount of the model sample when converted into a neutron irradiation amount. Third storage means for preliminarily storing the relationship between the neutron irradiation dose and the irradiation embrittlement amount, the neutron irradiation dose, and the operating period of a nuclear reactor whose constituent material is an actual sample having substantially the same composition as the model sample And a fourth storage unit that stores the relationship of No. 1 in advance.

Next, the contents of each storage means will be described with reference to FIG. FIG. 6 is a graph showing the content of data stored in advance. FIG. 6A is a graph showing the contents of the first storage means, where the vertical axis represents the amount of change in mechanical characteristic value,
The horizontal axis represents the irradiation embrittlement amount. The amount of change in mechanical characteristic value shown on the vertical axis is, for example, the amount of change in hardness before and after ion irradiation, 0.
It refers to the amount of increase in 2% proof stress. The irradiation embrittlement amount shown on the horizontal axis refers to a ratio of break elongation before and after ion irradiation (break elongation after ion irradiation / break elongation before ion irradiation).

An example of this measurement is shown in FIGS. Figure 9
6 is a graph showing the relationship between the amount of change in hardness of a model sample subjected to ion irradiation and the amount of irradiation embrittlement, where the vertical axis represents the amount of irradiation change and the horizontal axis represents the amount of change in hardness. FIG. 10 is a graph showing the relationship between the increase amount of 0.2% proof stress of a model sample subjected to ion irradiation and the irradiation embrittlement amount, in which the vertical axis represents the irradiation change amount and the horizontal axis represents 0.2%. Indicates the increase in yield strength. As can be seen from both figures, as the amount of change in hardness and strength increases,
It can be seen that the amount of irradiation embrittlement decreases, the elongation at break decreases, and the model sample embrittles. FIG. 13 is a graph showing the relationship between the ratio of rupture elongation before and after irradiation (irradiation embrittlement amount) and the increase in hardness of austenitic stainless steel subjected to neutron irradiation. The breaking elongation ratio is shown, and the vertical axis shows the increase in hardness. The circle indicates SU
These are the results for S304 series materials, and the triangle marks are SUS.
It is a result about a 316 series material. Results similar to those shown in FIG. 9 were obtained.

FIG. 6B is a graph showing the contents of the second storage means, in which the vertical axis represents the stress corrosion cracking susceptibility of the model sample irradiated with ions and the horizontal axis represents the irradiation embrittlement amount. The stress corrosion cracking susceptibility shown on the vertical axis means the ratio of the grain boundary type stress corrosion cracking fracture surface ratio before and after irradiation. Further, the critical irradiation embrittlement amount shown in the figure, the irradiation embrittlement amount when the grain boundary type stress corrosion cracking fracture surface begins to be observed, generally, irradiation when the risk of stress corrosion cracking increases It corresponds to the amount of embrittlement.

An example of this measurement is shown in FIG. FIG. 11 is a graph showing the relationship between the amount of irradiation embrittlement and the intergranular stress corrosion cracking (IGSCC) fracture surface ratio. This IGSCC fracture rate is
It was determined by observing the sample after fracture with an electron microscope.

FIG. 6C is a graph showing the contents of the third storage means, in which the vertical axis represents the neutron irradiation amount corresponding to the ion irradiation amount with which the model sample was irradiated, and the horizontal axis represents the irradiation embrittlement amount.
This irradiation embrittlement amount is a uniform amount that represents the amount of embrittlement due to particle irradiation, and the ion irradiation amount that gives a certain amount of embrittlement can be converted into a neutron irradiation amount. The graph showing this conversion result is the graph shown in FIG. This conversion method is 1 dpa≈1 × 10 ²¹ n / cm ² . dpa
Represents the number of target atoms ejected per atom of the incident particle. Further, the neutron critical dose refers to the neutron dose corresponding to the critical irradiation embrittlement dose shown in FIG.

FIG. 6D is a graph showing the contents of the fourth storage means, where the vertical axis represents the neutron irradiation dose of the actual sample loaded in the reactor and the horizontal axis represents the operating period of the reactor. Here, the reactor operation critical period refers to a reactor operation period corresponding to the neutron critical dose.

The above-mentioned FIGS. 6 (a), (b), (c),
The contents of (d) may be displayed on the output means such as the CRT 4 if necessary.

Next, the calculation section 60 will be described. The calculation unit 60 corresponds to the irradiation embrittlement amount corresponding to the mechanical characteristic value change amount of the actual sample, which is obtained from the first storage unit, and the irradiation embrittlement amount obtained from the first calculation unit. Second calculating means for obtaining the neutron irradiation amount to the actual sample from the third storing means, and third calculating means for obtaining the reactor operation period corresponding to the neutron irradiation amount obtained from the second calculating means from the fourth storing means And a fourth calculation means for obtaining, from the third storage means, the neutron critical irradiation dose to the actual sample, which corresponds to the critical irradiation embrittlement amount causing the stress corrosion cracking stored in the second storage means. The reactor operation critical period corresponding to the neutron critical dose obtained from the means is obtained from the fourth storage means, and this reactor operation critical period is compared with the reactor operation period,
And a fifth calculation means for calculating the remaining life from the difference.

Next, a method of measuring the remaining life of a material using this remaining life estimation device 200 will be described. This method will be described with reference to the flowchart shown in FIG. FIG. 5 is a flowchart of the remaining life estimation method according to the present embodiment. First, the amount of change in the mechanical property value of the actual sample that has been irradiated with neutrons in the reactor is input (step 8).
1). Next, the amount of change in the mechanical characteristic value of the model sample having substantially the same composition as the actual sample irradiated with a predetermined amount of ions,
The irradiation embrittlement amount corresponding to the change amount of the mechanical characteristic value of the actual sample is obtained from the first storage unit that stores the relationship with the irradiation embrittlement amount of the model sample in advance (step 82). Next, a neutron equivalent to the ion irradiation amount to the model sample is stored from the third storage unit that stores the relationship between the neutron irradiation amount and the irradiation embrittlement amount when the ion irradiation amount is converted into the neutron irradiation amount. The dose is calculated (step 83). Next, the relationship between the amount of ion irradiation to the model sample and the irradiation embrittlement amount of the model sample, and the critical irradiation embrittlement amount, which is the irradiation embrittlement amount when the grain boundary type stress corrosion crack fracture surface begins to be observed in the model sample. The neutron irradiation dose to the actual sample corresponding to the irradiation embrittlement amount of the actual sample is obtained from the second storage unit that stores the critical ion irradiation amount corresponding to the conversion amount in advance (step 84). next,
When the neutron irradiation dose to the actual sample is equal to or more than the neutron critical irradiation dose (step 85), that fact is output (step 8).
6). Next, when the neutron irradiation dose to the actual sample is less than the neutron critical irradiation dose, the relationship between the neutron irradiation dose to the actual sample and the neutron irradiation period to the actual sample is stored in advance from the fourth storage means. The neutron irradiation period corresponding to the neutron irradiation amount of the actual sample is obtained (step 87). Next, either or both of the difference and the ratio between the neutron irradiation period and the neutron irradiation critical period corresponding to the neutron critical irradiation dose are obtained (step 88), and the remaining life is displayed (step 8).
9).

In this case, when the relationship between the neutron irradiation dose received by the actual sample and the irradiation embrittlement amount obtained by the first storage unit from the change amount of the mechanical properties of the actual sample is different from that of the third storage unit. The relationship between the neutron irradiation dose and the irradiation embrittlement dose in the third storage means can be corrected. A safety factor can be used for the critical embrittlement amount at which stress corrosion cracking occurs.

Since the above processing is performed by using the residual life estimation apparatus 200 according to the present embodiment, the operator can check the hardness and strength of the actual sample which is the metal sample neutron-irradiated in the reactor. By measuring the amount of change, it is possible to predict the life of a nuclear material subjected to neutron irradiation at a high temperature against stress corrosion cracking, and this has a great effect on preventive maintenance of a nuclear plant. The amount of change in mechanical property value refers to the difference in 0.2% proof stress, hardness, elongation at break and tensile elongation before and after particle irradiation. Further, instead of the change amount of the mechanical characteristic value, the change amount of the electric characteristic value such as the difference between the electric resistance before and after the irradiation and the eddy current may be input.

The critical irradiation embrittlement amount represents the amount of embrittlement at which the material exhibits stress corrosion cracking susceptibility, and when the stress corrosion cracking fracture surface is allowed to reach a certain value, for example, 10 or 20%. In addition, the amount of embrittlement corresponding to this can be the critical irradiation embrittlement amount.

Next, regarding the remaining life of the operating reactor,
A case where the technique of the second embodiment is applied will be described. Find the amount of embrittlement of nuclear components that have been used up to now. For this purpose, for example, used materials of the operating nuclear reactor are used as test materials. An embrittlement amount equivalent to the obtained embrittlement amount is given to an actual sample by a combination of cold working and heat treatment. This actual sample is loaded into the operating reactor and used for estimating the remaining life. Furthermore, as a method for measuring the hardness of the actual sample placed in the operating nuclear reactor, a measuring method using ultrasonic waves can be used. This method sends ultrasonic waves to a sample placed in an operating nuclear reactor, receives a reflected wave from the sample, and measures the hardness of the sample from the characteristics of the reflected wave. This method can measure hardness without removing the sample from the nuclear reactor and without damaging the sample.

In the above-mentioned second and third embodiments, the user inputs the measurement results by the keyboard 1, but the present invention is not limited to this, and the sample can be input from the sample as in the first embodiment. It is of course possible to input directly from the measuring device 14.

The present invention can be applied not only to austenitic stainless steel, but also to Inconel alloys used for springs and bolt materials, zirconium alloys for fuel cladding tubes, and the like.

[0078]

According to the present invention, there is an effect that the remaining life due to embrittlement of a material irradiated with high-energy particles or electromagnetic waves can be judged from simple compliance and physical quantities such as hardness and strength.

[Brief description of drawings]

FIG. 1 is a block diagram of a remaining life estimation apparatus according to a second embodiment.

FIG. 2 is a flowchart of a remaining life estimation method according to a second embodiment.

FIG. 3 is a graph showing the contents of a storage unit of the remaining life estimation apparatus according to the second embodiment.

FIG. 4 is a block diagram of a remaining life estimation device according to a third embodiment.

FIG. 5 is a flowchart of a remaining life estimation method according to the third embodiment.

FIG. 6 is a graph showing the content of data stored in advance in the storage unit of the remaining life estimation apparatus according to the third example.

FIG. 7 is a sectional view showing a neutron instrumentation tube for loading an actual sample.

FIG. 8 is a graph showing the intensity distribution of neutron irradiation dose in the axial direction of the neutron instrumentation tube.

FIG. 9 is a graph showing the relationship between the amount of change in hardness of a sample subjected to ion irradiation and the amount of irradiation embrittlement.

FIG. 10 is a graph showing the relationship between the amount of increase in 0.2% proof stress of an ion-irradiated sample and the amount of irradiation embrittlement.

FIG. 11 is a graph showing the relationship between the amount of irradiation embrittlement and the grain boundary type stress corrosion cracking fracture rate.

FIG. 12 is a graph showing the relationship between the ratio of fracture elongation before and after irradiation of austenitic stainless steel subjected to neutron irradiation and the grain boundary stress corrosion cracking fracture surface ratio.

FIG. 13 is a graph showing the relationship between the ratio of elongation at break and the increase in hardness before and after irradiation of neutron-irradiated austenitic stainless steel.

FIG. 14 is a perspective view showing the shape of a sample according to the first embodiment of the present invention.

FIG. 15 is a perspective view showing the configuration of the measuring apparatus according to the first embodiment of the present invention.

FIG. 16 is a cutaway perspective view showing the configuration of a nuclear reactor to which the first embodiment of the present invention has been applied.

FIG. 17 is a block diagram showing the configuration of a remaining life estimation apparatus according to the first embodiment of the present invention.

FIG. 18 is a graph showing a relationship between a load P and a crack opening displacement Φ for test pieces having different crack lengths a of samples.

FIG. 19 is a graph showing the relationship between the sample compliance λ (= EBΦ / P, E; Young's modulus, B: test piece plate thickness) and the crack length a in a simulated reactor environment.

FIG. 20: Crack length a and time t in a simulated reactor environment
The graph which shows the relationship of.

FIG. 21: Crack growth rate da / in simulated reactor environment
The graph which shows the relationship between dt and the stress intensity factor K.

FIG. 22 is a flowchart showing a life prediction operation by the remaining life prediction apparatus according to the first embodiment of the present invention.

FIG. 23 is a block diagram showing the configuration of the first embodiment of the present invention.

[Explanation of symbols]

1 ... Keyboard, 2, 60 ... Arithmetic unit, 3, 70 ... Storage unit, 4 ... CRT, 170 ... Neutron instrumentation tube 21, 61 ...
First computing means, 22, 62 ... Second computing means, 23, 63
... third arithmetic means, 24, 64 ... fourth arithmetic means, 65 ... fifth arithmetic means, 31, 71 ... first storage means, 32, 72 ...
Second storage means 33, 73 ... Third storage means 74 ... Fourth
Storage means, 11 ... Sample, 12 ... Fatigue pre-crack, 13 ... Radiation resistant internal load cell, 14 ... Crack measuring device, 15 ... Restraining jig, 16 ... Screw, 17 ... Reactor pressure vessel, 19 ... Computing device , 111 ... Function compensation device, 113 ... Timer, 11
2 ... storage device, 170 ... neutron instrumentation tube, 10 ... display device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shizuo Matsushita 4026 Kuji Town, Hitachi City, Hitachi, Ibaraki Prefecture Hitachi Research Institute, Ltd. (72) Shigeki Kasahara 4026 Kuji Town, Hitachi City, Ibaraki Prefecture, Hitachi Corporation Inside Hitachi Research Laboratory (72) Inventor Michiyoshi Yamamoto 3-1-1 1-1 Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Works

Claims (26)

[Claims] 1. A relationship between a physical quantity of a plurality of types of model samples obtained by exposing a material whose mechanical properties are deteriorated by being exposed to high energy radiation to high energy radiation under a plurality of exposure conditions and an exposure period. The first step to obtain, the second step to obtain the critical exposure period until the material causes unstable fracture from the relation obtained in the first step, from the material having substantially the same composition as the model sample A third step of placing the actual sample in a high-energy radiation irradiation environment of a measurement target including the material as a constituent member, a fourth step of measuring a physical quantity of the actual sample after irradiation, and a first step From the relationship between the physical quantity and the exposure period obtained in step 4, find the actual exposure period corresponding to the physical amount of the actual sample obtained in the fourth step, and use this as the actual exposure period of the measurement target. And a sixth step of obtaining the difference between the critical exposure period of the second step and the actual exposure period of the measurement object of the fourth step. 2. The first step according to claim 1, wherein the first step for obtaining the relationship between the physical quantity of a plurality of types of model samples and the exposure quantity, and the exposure quantity and the measurement corresponding to the exposure quantity. A second step of obtaining a relationship with an exposure period of an object, wherein the second step uses the relationship obtained in the first step to cause critical brittleness of the material leading to unstable fracture. Corresponding to the critical exposure amount from the second step of obtaining the amount of criticality and the critical exposure amount corresponding to the critical embrittlement amount, and the relationship between the exposure amount obtained in the first step and the exposure period. The second remaining step of obtaining the relationship between the critical exposure period of the measurement target and the remaining life estimation method. 3. The residual life estimation method according to claim 1, wherein the material is an iron-based structural material. 4. The residual life estimation method according to claim 1, wherein the measurement target is a nuclear power plant. 5. The residual life estimation method according to claim 1, wherein the physical quantity includes the irradiation embrittlement amount of the iron-based material as an essential parameter. 6. The relationship between the physical quantity and the exposure period of a plurality of types of model samples obtained by exposing a material whose mechanical properties are deteriorated by being exposed to high energy radiation to high energy radiation under a plurality of exposure conditions. The first step to obtain, the second step to obtain the critical exposure period until the material causes unstable fracture from the relation obtained in the first step, from the material having substantially the same composition as the model sample In the third step of placing the actual sample in the high-energy radiation irradiation environment of the measurement target containing the material as a constituent member, the fourth step of taking in the physical quantity of the actual sample after irradiation at any time, and the first step. From the relationship between the obtained physical quantity and the exposure period, the actual exposure period corresponding to the physical quantity of the actual sample obtained in the fourth step is obtained, and this is the fifth exposure step which is the actual exposure period of the measurement target. And a sixth step of obtaining the difference between the critical exposure period of the second step and the actual exposure period of the measurement object of the fourth step. 7. The method according to claim 6, wherein the first step is to obtain the relationship between the physical quantity of a plurality of types of model samples and the exposure amount, and the exposure amount and the measurement corresponding to the exposure amount. A second step of obtaining a relationship with an exposure period of an object, wherein the second step uses the relationship obtained in the first step to cause critical brittleness of the material leading to unstable fracture. Corresponding to the critical exposure amount from the second step of obtaining the amount of criticality and the critical exposure amount corresponding to the critical embrittlement amount, and the relationship between the exposure amount obtained in the first step and the exposure period. The second remaining step of obtaining the relationship between the critical exposure period of the measurement target and the remaining life estimation method. 8. The residual life estimation method according to claim 6, wherein the material is an iron-based structural material. 9. The residual life estimation method according to claim 6, wherein the measurement target is a nuclear power plant. 10. The residual life estimation method according to claim 6, wherein the physical quantity includes the irradiation embrittlement amount of the iron-based material as an essential parameter. 11. The relationship between the physical quantity of a plurality of types of model samples obtained by exposing a material, whose mechanical properties are deteriorated by being exposed to high energy radiation, to high energy radiation under a plurality of exposure conditions, and the exposure period. The first step to obtain, the second step to obtain the critical exposure period until the material causes unstable fracture from the relation obtained in the first step, from the material having substantially the same composition as the model sample And a third step of installing the actual sample and the means for measuring the actual sample and the physical quantity thereof in a high-energy radiation irradiation environment of a measurement target including the material as a constituent member, the physical quantity of the actual sample after irradiation From the relationship between the physical quantity obtained in the 4th step and the 1st step and the exposure period, the actual exposure period corresponding to the physical quantity of the actual sample obtained in the 4th step is calculated. A remaining life including a fifth step in which this is the actual exposure period of the measurement target, and a sixth step of obtaining a difference between the critical exposure period of the second step and the actual exposure period of the measurement target in the fourth step. Estimation method. 12. The method according to claim 11, wherein the first step is to obtain the relationship between the physical quantity of a plurality of types of model samples and the exposure amount, and the exposure amount and the measurement corresponding to the exposure amount. The first two to find the relationship with the exposure period of the subject
And the critical step corresponding to the critical embrittlement amount that causes the material to undergo unstable fracture from the relationship obtained in the first step. A second step of obtaining the exposure amount and a relationship of the critical exposure period of the measurement object corresponding to the critical exposure amount from the relationship between the exposure amount and the exposure period obtained in the first second step 2) The remaining life estimation method including the steps 2 and. 13. The residual life estimation method according to claim 11, wherein the material is an iron-based structural material. 14. The residual life estimation method according to claim 11, wherein the measurement target is a nuclear power plant. 15. The residual life estimation method according to claim 11, wherein the physical quantity includes the irradiation embrittlement amount of the iron-based material as an essential parameter. 16. A model sample obtained based on a plurality of types of model samples obtained by exposing a material whose mechanical properties are deteriorated by being exposed to high energy radiation to high energy radiation under a plurality of exposure conditions. A first storage means for storing the relationship between the physical quantity and the exposure period of the first storage element, and a first exposure means for determining the critical exposure period until the material undergoes unstable destruction by irradiation from the relationship stored in the first storage means.
Computing means, an actual sample which is installed in a high-energy radiation environment to be measured and which contains substantially the same material as the model sample as a constituent member, and which is made of a material having substantially the same composition as the model sample From the relationship between the physical quantity stored in the first storage means and the exposure period, the actual exposure period corresponding to the physical quantity of the actual sample captured by the capturing means is obtained, and is obtained from the means. A remaining life estimation device comprising a means for determining a difference between the actual exposure period of the measurement target and the critical exposure period determined by the first calculation means, which is the actual exposure period of the measurement target. 17. The first storage means according to claim 16, wherein the first storage means stores the relationship between the physical quantity of a plurality of types of model samples and the exposure quantity, and the exposure quantity and its exposure quantity. And a first second storage means for storing a relationship with the exposure period of the measurement target corresponding to the first calculation means, and the first arithmetic means is unstable due to the relationship stored in the first first storage means. Using the relation stored in the first first computing means and the first second storage means for obtaining the critical embrittlement amount leading to fracture and the critical exposure amount corresponding to the critical embrittlement amount, A first second calculating means for obtaining a relationship between the critical exposure period of the measurement target corresponding to the critical exposure amount,
Remaining life estimation device. 18. The residual life estimation device according to claim 16, wherein the material is an iron-based structural material. 19. The residual life estimation device according to claim 16, wherein the measurement target is a nuclear power plant. 20. The remaining life estimation device according to claim 16, wherein the physical quantity includes the irradiation embrittlement amount of the iron-based material as an essential parameter. 21. A model sample obtained based on a plurality of types of model samples obtained by exposing a material, whose mechanical properties are deteriorated by being exposed to high energy radiation, to high energy radiation under a plurality of exposure conditions. A first storage means for storing the relationship between the physical quantity and the exposure period of the first storage element, and a first exposure means for determining the critical exposure period until the material undergoes unstable destruction by irradiation from the relationship stored in the first storage means.
Computing means, an actual sample which is installed in a high-energy radiation environment to be measured and which contains substantially the same material as the model sample as a constituent member, and which is made of a material having substantially the same composition as the model sample And means for outputting a physical quantity relating to the mechanical characteristics of the actual sample, means for taking in the physical quantity after irradiation of the actual sample output by the output means at any time, from the relationship between the physical quantity stored in the first storage means and the exposure period , The actual exposure period corresponding to the physical quantity of the actual sample taken in by the capturing means is defined as the actual exposure period of the measurement target, and the actual exposure period of the measurement target and the critical exposure period determined by the first computing means A remaining life estimation device including means for determining the difference between 22. The first storage means according to claim 21, wherein the first storage means stores the relationship between the physical quantity of a plurality of types of model samples and the exposure quantity, and the exposure quantity and its exposure quantity. And a first second storage means for storing a relationship with the exposure period of the measurement target corresponding to the first calculation means, and the first arithmetic means is unstable due to the relationship stored in the first first storage means. Using the relation stored in the first first computing means and the first second storage means for obtaining the critical embrittlement amount leading to fracture and the critical exposure amount corresponding to the critical embrittlement amount, A first second calculating means for obtaining a relationship between the critical exposure period of the measurement target corresponding to the critical exposure amount,
Remaining life estimation device. 23. The remaining life estimation device according to claim 21, wherein the physical quantity from the output means is a load on an actual sample. 24. A model sample obtained based on a plurality of types of model samples obtained by exposing a material whose mechanical properties are deteriorated by being exposed to high energy radiation to high energy radiation under a plurality of exposure conditions. A first storage means for storing the relationship between the physical quantity of the material and the exposure period, and a first exposure means for determining the critical exposure period until the material undergoes unstable destruction by irradiation from the relationship stored in the first storage means.
Computing means, an actual sample which is installed in a high-energy radiation irradiation environment of a measurement target including substantially the same material as the model sample as a constituent member, and which is made of a material having substantially the same composition as the model sample From the relation between the physical quantity stored in the first storage means and the exposure period, the actual exposure period corresponding to the physical quantity of the actual sample output from the output means is obtained, This is the actual exposure period of the measurement target,
A remaining life estimation device including means for obtaining a difference between the actual exposure period of the measurement target and the critical exposure period obtained by the first calculation means. 25. The first storage means according to claim 24, wherein the first storage means stores the relationship between the physical quantity of a plurality of types of model samples and the exposure quantity, and the exposure quantity and its exposure quantity. And a first second storage unit that stores a relationship with the exposure period of the measurement target corresponding to the first calculation unit, and the first calculation unit is unstable due to the relationship stored in the first first storage unit. Using the relation stored in the first first computing means and the first second storage means for obtaining the critical embrittlement amount leading to fracture and the critical exposure amount corresponding to the critical embrittlement amount, A first second calculating means for obtaining a relationship between the critical exposure period of the measurement target corresponding to the critical exposure amount,
Remaining life estimation device. 26. The remaining life estimation apparatus according to claim 24, wherein the real sample is pre-notched before being installed in an exposed environment.