WO2011013376A1

WO2011013376A1 - Test container and test method using same

Info

Publication number: WO2011013376A1
Application number: PCT/JP2010/004807
Authority: WO
Inventors: 一成藤原; 英朗田中; 美和笹沼; 博男雨澤; 甚作細川; 勇一小沼; 隆齋藤; 邦雄鬼沢; 義幸坂詰
Original assignee: 日本原子力発電株式会社; 東京電力株式会社; 東北電力株式会社
Priority date: 2009-07-30
Filing date: 2010-07-29
Publication date: 2011-02-03
Also published as: JP2011033399A; JP5205644B2

Abstract

A test container provided with a generated gas mixing section (10c) to which and from which a sweep gas is supplied and discharged, and also with a containing section (40b, 50b) which is disposed adjacent to the generated gas mixing section, has at least one small hole (40a, 50a) for discharging, to the generated gas mixing section, gas which is generated during a test from a body (A, B) being tested, and contains and encapsulates the body except the small hole. The test container can prevent the body being tested from excessively drying.

Description

Test container and test method using the test container

The present invention can prevent excessive drying of the specimen due to the sweep gas by providing a specimen storage section for storing the specimen, particularly the concrete specimen, and appropriately influence the radiation on the specimen. The present invention relates to a test container that can be evaluated and a test method thereof.

In recent years, research on the properties of concrete receiving radiation has been underway. Generally, the radiation irradiation test is performed by irradiating a test container storing a test body such as concrete or metal with radiation.

In the radiation irradiation test of concrete, when the concrete stored in the test container is irradiated with radiation, the moisture in the concrete is decomposed and hydrogen gas is generated. For this reason, in the case of a completely sealed test container, the hydrogen gas concentration continues to rise. Since various problems occur when the hydrogen gas concentration in the test container increases, the hydrogen gas concentration in the test container is preferably 4% or less.

As a structure that makes it possible to reduce the hydrogen gas concentration in the test container, for example, there is a structure in which helium gas having a humidity of 0% is supplied into the test container and the gas generated in the test container is flowed out (for example, Non-Patent Document 1).

According to the test container described in Non-Patent Document 1, it is possible to remove the gas generated from the specimen by bringing the helium gas into direct contact with the concrete specimen.

Furthermore, according to Non-Patent Document 2, it is said that heat generation due to radiation is also affecting the performance of concrete, and there are many documents in which the strength decreases when a concrete specimen is exposed in a high temperature environment. Therefore, there is a need for a test method that takes into account the effects of heat generated by radiation.

However, according to the test container described in Non-Patent Document 1, since the helium gas directly contacts the concrete specimen, the concrete specimen is exposed to severe dry conditions for a long time. There is a possibility of deterioration. Depending on the degree of deterioration, it may not be possible to determine the presence or absence of radiation from the test results.

Also, a method of supplying moisture by adding moisture to the supplied helium gas can be considered. In this case, it is preferable to set the inside of the test container to 60 ° C. and 60% RH, but it is difficult to control with a current radiation irradiation apparatus or the like. A large-scale remodeling to prevent supply loss is necessary, which is not realistic. Moreover, since it is necessary to use pure water for moisture to prevent activation of impurities contained in water, there is a possibility that concrete will be further deteriorated by using pure water.

Also, it is necessary to appropriately evaluate the influence of radiation on the concrete specimen, taking into account the effect of heat on the concrete specimen.

The present invention has been made to solve such a conventional problem. By providing a test specimen storage container having a small hole, it is possible to prevent the test specimen from being dried and to the test specimen. It is an object of the present invention to provide a test container and a test method capable of appropriately evaluating the effects of radiation.

The test container of the present invention is disposed adjacent to the generated gas mixing section where the sweep gas is supplied and discharged, and discharges the gas generated from the specimen during the test to the generated gas mixing section. And at least one small hole portion, and a test body storage portion that seals and stores the test body other than the small hole portion.

In addition, the test method of the present invention includes a test body stored in a test container and irradiated with radiation to perform a radiation irradiation test, and the test body is stored in a test container and heated only at the monitoring temperature of the radioactive irradiation test. The test is performed, and the result of the radiation irradiation test is compared with the result of the irradiation effect confirmation test to separate and evaluate the influence of radiation on the specimen.

According to the test container and the test method of the present invention, it is possible to prevent excessive drying of the specimen, and at the same time, it is possible to appropriately evaluate the influence of radiation on the specimen.

It is sectional drawing which shows the structure of the test container of embodiment of this invention. It is a figure which shows the relationship of the radiation irradiation test and influence confirmation test of this embodiment. It is a figure explaining the prior confirmation test method which confirms the drying prevention effect of the test container of this invention. It is a figure which shows an example of the gas concentration measurement result of the hydrogen gas and oxygen gas which generate | occur | produced during irradiation. It is a figure which shows the relationship between a fast neutron irradiation amount and the compressive strength of a concrete test body. It is a figure which shows the relationship between a fast neutron irradiation amount and the static elastic modulus of a concrete test body. It is a figure which shows the relationship between the neutron irradiation amount and the compressive strength put together by Hilsdorf et al. It is the figure which the present inventors screened and rearranged FIG.

Hereinafter, a test container which is an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the radiation irradiation test will be mainly described as an example, but the present invention is not limited to this, and can naturally be used for general tests. In the following description, the test container of the present embodiment is also referred to as a semi-seal container. Here, the semi-seal refers to a seal that does not completely seal but has a small hole for degassing.

FIG. 1 is a cross-sectional view showing the configuration of the test container of the present embodiment. The test container 100 of the present embodiment has a circular cross section of about φ60 mm, and the overall length of the container main body has an outer shape of approximately 1300 mm. In addition, the full length and shape of the test container of this embodiment are not restricted to this, It can change suitably according to the shape etc. of a test body (for example, prismatic shape etc.).

The test container 100 of the present embodiment includes an outer cylinder container 10, a discharge pipe 20, a supply pipe 30, a first inner cylinder container 40, and a second inner cylinder container 50.

The outer cylinder container 10 has a substantially hollow cylindrical shape. The upper end plug 10a is provided in the upper part inside the outer cylinder container 10, and the lower end plug 10b is provided in the lower part. A space between the upper end plug 10a and the lower end plug 10b (hereinafter referred to as a generated gas mixing unit 10c) is kept airtight with respect to the outside.

The supply pipe 30 penetrates the upper end plug 10a from the upper part of the outer cylindrical container 10 and enters the generated gas mixing part 10c, and the outlet part 30a of the supply pipe 30 is arranged at the lower part in the generated gas mixing part 10c. Is done. And the supply pipe | tube 30 supplies the sweep gas from the sweep gas supply apparatus not shown to the generation gas mixing part 10c.

The discharge pipe 20 passes through the upper end plug 10a from the upper part of the outer cylindrical container 10 and enters the generated gas mixing part 10c, and the inlet part 20a of the discharge pipe 20 is arranged at the upper part in the generated gas mixing part 10c. Is done. The discharge pipe 20 discharges the sweep gas from the generated gas mixing unit 10c to the outside.

With such a configuration, a flow in a certain direction of the sweep gas from the outlet part 30a of the supply pipe 30 toward the inlet part 20a of the discharge pipe 20 is formed inside the outer cylinder container 10.

1st inner cylinder container 40 is arrange | positioned at the upper part in generated gas mixing part 10c, and the lower part of the inlet part 20a of the discharge pipe 20. As shown in FIG. The first inner cylinder container 40 has a gas vent hole 40a having a diameter of about φ1 mm that is very small with respect to the diameter of the container. On the side to be). And the 1st inner cylinder container 40 stores the concrete test body A in the test body storage part 40b substantially sealed in places other than the gas vent hole 40a.

The second inner cylinder container 50 is disposed in the lower part of the generated gas mixing unit 10 c and in the lower part of the first inner cylinder container 40. Similarly to the first inner cylinder container 40, the second inner cylinder container 50 has a gas vent hole 50a having a diameter of about φ1 mm. The gas vent hole 50a is formed in the container upper surface direction (that is, the first inner cylinder container 50). It is arranged on the side facing the cylindrical container 40. And the 2nd inner cylinder container 50 stores the concrete test body B in the test body storage part 50b substantially sealed in places other than the gas vent hole 50a.

The distance between the inner wall of the first inner cylinder container 40 and the side surface of the concrete specimen A and the distance between the inner wall of the second inner cylinder container 50 and the side surface of the concrete specimen B should be 0.1 to 0.2 mm. Is preferred. This is because the generated hydrogen gas and oxygen gas are not properly discharged when the inner wall of the inner cylinder container and the concrete specimen are in close contact, and when the interval is wider than 0.2 mm, This is because it is considered that the drying of the concrete specimen is likely to proceed.

In the present embodiment, the number of inner cylinder containers is two, but the number is not limited to this, and the number can be increased or decreased as appropriate according to the number of test specimens.

Next, a method for using the test container of this embodiment will be described.

First, the test bodies A and B are stored in the first inner cylinder container 40 and the second inner cylinder container 50, respectively. Then, the inner

cylindrical containers

40 and 50 are arranged in the generated gas mixing section 10c in which the flow of the sweep gas is formed in the inside so that the small holes face the downstream direction of the flow of the sweep gas. And store.

Next, after loading the test container 100 of the present embodiment on an apparatus for irradiating radiation, a sweep gas (for example, helium gas) with a predetermined flow rate is supplied from the supply pipe 30 into the generated gas mixing unit 10c.

The supplied helium gas is supplied from the outlet portion 30a of the supply pipe 30 and is discharged from the inlet portion 20a of the discharge pipe 20. Therefore, the helium gas in a certain direction from the lower part to the upper part of the generated gas mixing part 10c. A flow is formed along the outside of the first inner cylinder container 40 and the second inner cylinder container 50.

Here, the concrete test bodies A and B are stored in the first inner cylinder container 40 and the second inner cylinder container 50, and the

gas vent holes

40a and 50a are arranged in the downstream direction of the flow of helium gas. Therefore, the flow of helium gas does not directly contact the concrete specimens A and B. Thereby, it becomes possible to prevent the concrete test bodies A and B from being excessively dried.

In addition, when the moisture in the concrete specimens A and B is decomposed into hydrogen and oxygen by irradiation, the

specimen storage parts

40b and 50b inside the first inner cylinder container 40 and the second inner cylinder container 50 are used. The generated hydrogen gas and oxygen gas are discharged from the

specimen storage parts

40b and 50b to the generated gas mixing part 10c through the

gas vent holes

40a and 50a having a diameter of about φ1 mm.

Further, since the inside of the generated gas mixing unit 10c is a constant pressure equivalent to the atmospheric pressure, the pressure in the

specimen storage units

40b and 50b is higher than the pressure in the generated gas mixing unit 10c during the test. Accordingly, the sweep gas in the generated gas mixing unit 10c does not flow into the

specimen storage units

40b and 50b from the

gas vent holes

40a and 50a.

The hydrogen gas released to the generated gas mixing unit 10c is discharged from the discharge pipe 20 to the outside of the test vessel 100 together with the helium gas flowing from the lower part to the upper part of the generated gas mixing part 10c. Thereby, it becomes possible to prevent the hydrogen gas concentration inside the test container 100 from being excessively increased.

As for the diameters of the

gas vent holes

40a and 50a, if the diameter is large, it is expected that moisture release from the concrete specimen accelerates and drying proceeds, and if the diameter is small, hydrogen gas may not be released sufficiently. . As a result of the evaluation by the present inventors, it has been found that the diameter of the

vent holes

40a, 50a is preferably about φ1 mm from the viewpoint of drying the concrete and releasing hydrogen gas.

Next, an influence confirmation test using the test container of this embodiment will be described.

In this test, concrete physical properties such as 1) compressive strength, 2) static elastic modulus, and 3) moisture content are targeted as items to evaluate the soundness of concrete receiving radiation. The test consists of a radiation test of a concrete specimen using the Japan Atomic Energy Agency's Material Test Reactor (JMTR) and an effect confirmation test to evaluate the result of the test. The related figure of each test is shown in FIG.

Since the radiation irradiation test is an accelerated irradiation test, it has been confirmed by preliminary analysis that the temperature of the concrete specimen rises to about 60 ° C due to internal heat generated by γ rays. Moreover, the test body is loaded in the semi-seal container for the purpose of avoiding extreme drying by the dry helium gas flowing in the test container. In order to analyze and evaluate the changes in the physical properties of concrete in structures that receive radiation, it is necessary to eliminate such conditions related to temperature and humidity that are peculiar to the test environment.

Therefore, in this test, in addition to the accelerated irradiation test, various “effect confirmation tests” (basic test, drying effect confirmation test, irradiation effect confirmation test) shown in FIG. 2 are performed.

(A) Radiation irradiation test Since the radiation irradiation test is an accelerated irradiation test, it was confirmed by the analysis for this test that the temperature of the specimen rises to about 60 ° C due to internal heat generation of the concrete specimen due to γ rays. ing. Moreover, the test body is loaded in the semi-seal container for the purpose of avoiding extreme drying by the dry helium gas flowing in the test container.

(B) Impact Confirmation Test The impact confirmation test is conducted to evaluate the difference between concrete subjected to radiation and concrete not subjected to radiation, namely, an irradiation effect confirmation test, a drying effect confirmation test, and a basic test.

i) Irradiation effect confirmation test The irradiation effect confirmation test is conducted to remove only the effects of radiation from the irradiation test and to extract only the effects of radiation. This is a test in which a test body is placed in a semi-seal container having the same shape as that of the radiation irradiation test, and the set temperature outside the container is heated at the monitoring temperature of the irradiation test (the average measured temperature of the test body in the radiation irradiation test).

ii) Drying effect confirmation test The drying effect confirmation test is carried out with the specimen exposed without using the semi-seal container from the irradiation effect confirmation test in order to evaluate the influence of the semi-seal container conditions. The temperature conditions are the same as in the irradiation effect confirmation test, and heating is performed at the monitoring temperature of the irradiation test, and the humidity is constant at 60% RH.

iii) Basic test The basic test is a test at a constant temperature of 20 ° C and a humidity of 60% RH in order to see the changes over time in the physical properties of the concrete specimen.

Table 1 is a table showing the results of an impact confirmation test using the test container of the present embodiment.

As can be seen from Table 1, the mass of the concrete specimen varies depending on the test method. Therefore, by comparing the data, it is possible to analyze the cause of the mass change of the concrete specimen.

Thus, it becomes possible to evaluate only the influence of radiation by comparing the results of the radiation irradiation test and the irradiation effect confirmation test. Further, by comparing the results of the irradiation effect confirmation test and the drying effect confirmation test, it becomes possible to evaluate the influence of the sealing condition. Moreover, it becomes possible to evaluate the influence of temperature by comparing the results of the drying effect confirmation test and the basic test. Further, by comparing the results of the radiation irradiation test and the basic test, it is possible to correct the strength standard and the age of the material.

As described above, the test container of this embodiment can prevent excessive drying of the test body, and at the same time, can facilitate the discharge of gas inside the test container.

In addition, according to the test method using the test container of the present embodiment, it is possible to appropriately evaluate the difference between the concrete that receives radiation and the concrete that does not receive radiation by performing an impact confirmation test.

In the above embodiment, the supplied sweep gas is helium gas. However, the present invention is not limited to this, and an inert gas or the like can be appropriately used according to the purpose of use.

Moreover, in the said embodiment, although hydrogen gas was mentioned and demonstrated as an example of unnecessary gas, it is not restricted to this, It is also possible to apply to the test body which generate | occur | produces gas other than hydrogen gas. .

In the above embodiment, the concrete test body is described as an example of the test body. However, the present invention is not limited to this, and the present invention can be applied to various test bodies that need to prevent drying.

Furthermore, in the above-described embodiment, the test container is a combination of the inner cylinder container and the outer cylinder container. However, the present invention is not limited to this. For example, the generated gas mixing section into which the sweep gas flows in and out, and the generated gas It is good also as an integral structure which has the test body storage part connected to a mixing part through a gas vent hole with a diameter of about φ1 mm.

(First Experiment Example)
Next, a test method using the test container of this embodiment will be described. A preliminary confirmation test for confirming the drying prevention effect of the test container of the present invention will be described as a first experimental example.

1． Purpose of the test In order to forcibly discharge the hydrogen gas generated during the irradiation test, helium gas with a humidity of 0% is flowed into the test container at a rate of about 60 cc / min. Confirm the effectiveness of semi-sealing of the test specimen, which is planned as a measure to prevent extreme drying of the test specimen, which is a concern when helium gas directly hits the concrete specimen.

2． Exam overview
2.1 Semi-sealed container (see Fig. 1)
(1) Material: SUS304
(2) Size Inner diameter: φ50.4mm
Height of the upper space in the container (the distance between the upper surface of the specimen and the upper wall of the inner cylinder container): 7 mm
Generated gas mixing area (generated gas mixing part 10c) height: 25 mm
(3) Structure: φ1mm hole is provided in the upper part, and all others are sealed.

2.2 Concrete specimen (1) Mixing: Same material, same composition and same manufacturing method as irradiation test concrete specimen (2) Size: φ50 × 100 (Dummy specimen: φ50 × 25)

2.3 Test parameters and number of test specimens Table 2 shows the test parameters and the number of test specimens.

2.4 Test method (see Fig. 3)
The experiment case is configured to supply 0% RH helium gas at 60cc / min to a semi-sealed container installed in a constant temperature / humidity chamber and exhaust the gas mixed with water vapor directly from the semi-sealed container to the outside of the constant temperature / humidity chamber. It was.

Also, in the comparative case and the standard case, the concrete specimens were left in the thermostatic / humidity bath and the curing room without sealing.

2.5 Measurement Items (1) Measurement Items: Mass (Before test start and after 30 days)
(2) A trap was provided in the gas vent pipe from the generated gas mixing area, and the humidity of the released gas was measured.

Table 3 is a table showing the test results.

3. Test results (1) The mass changes in the experimental case and the standard case are almost the same.
(2) Compared with the experimental case and the standard case, the change in mass is four times or more larger.

4. Conclusion It was confirmed that the semi-sealed container in which the concrete specimen was sealed in a container with only a hole with a diameter of 1 mm was effective as a preventive measure against extreme drying of the specimen with helium gas at 0% humidity.

(Second Experimental Example)
Next, actual concrete evaluation using the test container of the present invention will be described as a second experimental example.

1. Test method
1.1 Concrete specimens Table 4 shows the mix of concrete specimens. The materials used to make the specimens were selected from those commonly used in Japanese nuclear power plants. The shape of the concrete test specimen was a cylindrical shape of φ50 mm × 100 mm in consideration of the size of the test container. After placing the concrete, it was sealed and cured for 3 months in an environment of 20 ° C and 60% RH, and then air-cured in the same environment until the start of the test. In order to compare the effects of irradiation on concrete specimens, tests using non-irradiated specimens exposed to an environment of 20 ° C and 60% RH during the irradiation period were also conducted.

1.2 Irradiation equipment Irradiation tests were conducted using a material testing reactor (JMTR) of the Oarai Research and Development Center, Japan Atomic Energy Agency.

1.3 Irradiation test container In this test, a stainless steel test container with a diameter of 60 mm and a height of about 1 m was used (see Fig. 1). In this test vessel, four concrete specimens (φ50mm × 100mm), four concrete specimens for temperature measurement with embedded thermocouples (φ50mm × 25mm), fluence monitor for measuring neutron irradiation, etc. Loaded.

1.4 Irradiation conditions (1) Temperature The temperature of the concrete specimen shall be below the limit of 65 ° C stipulated by the Japan Society of Mechanical Engineers' concrete reactor containment standard, which is the design standard for nuclear power plants in Japan. It was a goal. The temperature limit value of 65 ° C is set based on the value (150 ° F) indicated in the American Society of Mechanical Engineers (ASME) standard for concrete reactor containment vessels. (Table 5)

(2) Neutron irradiation amount Based on the irradiation conditions in the selected irradiation holes, three levels of neutron irradiation amount were set. Table 6 shows the target neutron dose for each of the three levels of steps. The final target neutron dose is 60 years of fast neutron dose outside the reactor pressure vessel of a standard boiling water reactor (BWR) (3.0 x 10 ¹⁸ n / cm ² (E> 0.1 MeV)) ) Neutron dose for 10 years in

Step

1, 60 years in

Step

2, and 40 years in Step 3.

(3) Concentration of generated gas When radiation is applied to concrete, moisture in the concrete is decomposed and hydrogen gas is generated. Therefore, in order to suppress the hydrogen gas concentration to 4% or less, a carrier gas having a constant flow rate is supplied into the test container and the generated gas is allowed to escape. Moreover, in order to confirm the density | concentration of generated gas, it measured regularly.

1.5 Measurement items The measurement items during irradiation and the measurement items using the concrete specimen after irradiation are shown below.
(1) During irradiation: temperature, neutron irradiation amount, generated gas concentration (hydrogen gas, oxygen gas, nitrogen gas)
(2) After irradiation: compressive strength, static elastic modulus, dimensions, appearance, scanning electron microscope (SEM) observation

2. Measurement results Table 7 shows a list of measurement results during irradiation.

(1) Temperature The temperature of the concrete specimen during irradiation satisfied the temperature limit value (65 ℃) or less at all steps.

(2) Neutron irradiation amount The neutron irradiation amount was calculated by analysis, and the analysis result was corrected by the neutron irradiation amount obtained from the activation amount of the fluence monitor.

The fast neutron irradiation dose exceeded the target value at all steps. Also, in Step 3, which assumed 40 years, the fast neutron dose (3.0 × 10 ¹⁸ n / cm ² (E> 0.1MeV)) for 60 years outside the reactor pressure vessel of a standard BWR It was over. The maximum fast neutron dose was 12.0 × 10 ¹⁸ n / cm ² (E> 0.1 MeV).

(3) Generated gas Fig. 4 shows an example of the gas concentration measurement results of hydrogen gas and oxygen gas generated during irradiation. Since the hydrogen gas concentration showed a peak immediately after the start of irradiation and then gradually decreased, it is considered that the decomposition of water due to the irradiation was stopped. The oxygen gas concentration was confirmed after about 100 hours from the start of irradiation and gradually decreased after about 400 hours. These trends showed the same trend at all steps.

In addition to these gases, nitrogen gas was also measured, but only a slight amount was detected at the start of irradiation.

3. Measurement results after irradiation
(1) Compressive strength Fig. 5 shows the relationship between the fast neutron dose and the compressive strength of the concrete specimen. The vertical axis of the figure shows the ratio of the compression strength of the irradiated specimen to the compressive strength (average value of four specimens) of the non-irradiated specimen.

As is clear from this figure, the compression strength of the irradiated specimen was equivalent to that of the non-irradiated specimen regardless of the irradiation amount. It was also found that the compressive strength was almost constant without being affected by the neutron dose up to the maximum dose of 12.0 × 10 ¹⁸ n / cm ² (E> 0.1 MeV) in this test.

(2) Static elastic modulus Figure 6 shows the relationship between the fast neutron dose and the static elastic modulus of the concrete specimen. The vertical axis of the figure shows the ratio of the static elastic modulus of the irradiated specimen to the static elastic modulus (average of four specimens) of the non-irradiated specimen.

The static elastic modulus of the irradiated specimen is about 60 years of fast neutron dose (3.0 × 10 ¹⁸ n / cm ² (E> 0.1MeV)) outside the standard BWR reactor pressure vessel. And there was no change. When it exceeds 6.0 × 10 ¹⁸ n / cm ² , there is a tendency to decrease slightly, but it is not a decrease that affects the concrete structure.

(3) Dimensions As a result of comparing the diameters and heights of the concrete specimens before and after irradiation, all specimens have a change rate of within ± 0.1%, which is equivalent to the measurement error of the measuring instrument, and there is almost no dimensional change due to irradiation. I found that there was no.

(4) Appearance / Scanning Electron Microscope (SEM) Observation No deformation or cracks were observed in the appearance of the concrete specimen after irradiation. Furthermore, in order to observe concrete microscopically, the specimen was crushed and SEM observation of the crushed surface was performed. As a result, no clear difference from the non-irradiated specimen was observed.

4). Comparison with previous knowledge The figure showing the relationship between neutron irradiation dose and compressive strength, published in Hilsdorf et al., Is used to evaluate the soundness of concrete in aged nuclear power plants in Japan. Quoted.

Figure 7 shows the tendency of compressive strength to decrease with increasing dose, but as a result of our investigation of the individual data plotted, it was found that the following data was included: .

(a) The temperature of the specimen during irradiation is a high temperature of 100 ° C or higher. (About 140 ℃ ~ 550 ℃)
(b) The size of the specimen is very small. (One side is 8mm to 15mm)
(c) Evaluation is based on bending strength data, not compressive strength.

There are many documents that show that compressive strength decreases when concrete is exposed to high temperature environments exceeding 100 ° C. For example, according to the Japan Concrete Institute “Concrete Handbook”, regarding the heat resistance of concrete, “the decrease in compressive strength is relatively small until around 100 ° C, but above that the residual compressive strength ratio is inversely proportional to the heating temperature. An example of a test result that concludes that “it tends to be smaller” is shown.

Generally, the higher the irradiation density, the higher the temperature of the specimen and the greater the influence of temperature. That is, the cause of the decrease in compressive strength is not only the dose, but also the effect of temperature during irradiation.

Therefore, the data corresponding to (a) to (c) in the data of FIG. 7 was screened and rearranged. The result is shown in FIG. According to this, although the range of neutron irradiation amount is limited, it turns out that the compressive strength of concrete does not fall with the increase in neutron irradiation amount. As a result of plotting the results of this test together with this figure, the range of irradiation dose in this test showed a tendency similar to the previous findings.

5. Summary From the above results, it was confirmed that, within the range of irradiation dose in this test, irradiation did not have a significant effect on the compressive strength of the concrete and had no significant effect on the shielding performance. In addition, in this test, knowledge such as the fact that there was almost no change in size and structure due to radiation, and the gas generation behavior due to radiolysis was obtained. These findings are considered to be useful not only for concrete structures of nuclear power plants, but also for long-term soundness assessment of nuclear facilities that receive radiation.

Claims

A generated gas mixing section for supplying and discharging a sweep gas;
It is arranged adjacent to the generated gas mixing part, and has at least one small hole part for discharging the gas generated from the specimen during the test to the generated gas mixing part, and the test is performed except for the small hole part. A specimen storage section for sealing and storing the body;
A test container comprising:
An outer tube container that includes the generated gas mixing unit and in which a flow in a certain direction of the sweep gas is formed;
An inner cylinder container provided inside the outer cylinder container with the test specimen storage section, with the small hole portion directed in the downstream direction of the flow of the sweep gas;
The test container according to claim 1, comprising:
The test container according to claim 1 or 2, wherein the test container is a test container for a radiation irradiation test.
The test container according to claim 1 or 2, wherein the test container is a test container for a heating test.
During the radiation irradiation test or the heating test, the gas generated from the test body causes the pressure in the test body storage part to be higher than the pressure in the generated gas mixing part, and the pressure from the small hole part into the test body storage part. The test container according to claim 1, wherein an inflow of the sweep gas is blocked.
The test body is stored in the test container according to any one of claims 1 to 5, and a radiation irradiation test is performed by irradiating with radiation.
The test body is stored in the test container according to any one of claims 1 to 5, and an irradiation effect confirmation test is performed in which only heating is performed at the monitoring temperature of the radioactive irradiation test,
A test method characterized in that the result of the radiation irradiation test and the result of the irradiation effect confirmation test are compared to separate and evaluate the influence of radiation on the specimen.
Without further storing the test body in the test container according to any one of claims 1 to 5, a drying effect confirmation test is performed in which heating is performed at the monitoring temperature of the radioactive irradiation test in an environment with a predetermined constant humidity. ,
The test method according to claim 6, wherein the result of the irradiation effect confirmation test and the result of the drying effect confirmation test are compared, and the influence of the test container on the test body is separated and evaluated. .
Without further storing the test body in the test container according to any one of claims 1 to 5, further conducting a basic test in which the test body is allowed to stand in an environment having a predetermined constant temperature and a predetermined constant humidity,
The test method according to claim 7, wherein the result of the drying effect confirmation test is compared with the result of the basic test, and the effect of the temperature on the test specimen is separated and evaluated.