JPH09211200A - Capsule for irradiation test - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to efficiently analyze the deterioration of a material due to irradiation when irradiation temperature and doses are used as parameters by enabling the radiation test on a sample in a desired irradiating condition without giving the sample a thermal and radioactive history in the start-up and shut-down of a reactor. SOLUTION: A capsule for irradiation tests has a sample holder 8 to hold a sample 5, a fixed shield 9a and a rotary shield 9b. The fixed radiation shield 9a, which is fixedly placed around the sample holder 8, is shaped like a partial cylinder whose side has a partial opening of some degrees. The rotary radiation shield 9b is placed around the sample holder 8 concentrically with the fixed shield 9a so that the shield 9b can freely rotate there and has a wider open angle than the fixed shield 9a. The rotary shield 9b is rotated on the central axis by a motor 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation irradiation test capsule for accommodating a sample for conducting a radiation irradiation test of neutron rays, gamma rays, etc., and particularly to a radiation capable of irradiating a sample with radiation under desired conditions. It relates to an irradiation test capsule.

[0002]

2. Description of the Related Art A radiation irradiation test of neutron rays, γ rays, etc. is carried out in order to inspect the influence of radiation deterioration of materials mounted in a nuclear reactor or the like. In such a radiation irradiation test, a sample is mounted in a place where radiation is generated in a nuclear reactor, etc., the sample is irradiated with radiation during the operation of the nuclear reactor, then the sample is taken out from the nuclear reactor, and the radiation deterioration is inspected. The test is done. In such a radiation irradiation test, a sample is stored in a cylindrical container called a capsule and mounted on a nuclear reactor or the like.

[0003]

The radiation deterioration of a material depends mainly on the irradiation temperature and the irradiation dose of the material. It is also known that even if the radiation dose is the same, the degree of radiation deterioration of the material differs if the radiation flux is different. Therefore, in order to accurately analyze the radiation deterioration of the sample due to radiation irradiation, it is necessary to set the irradiation conditions such as irradiation temperature and irradiation dose during irradiation of the sample to the desired conditions before conducting the irradiation test. Is.

However, when the nuclear reactor is operated, the output of the nuclear reactor gradually rises from the start of the operation, and after a certain amount of time, a constant output is maintained and then a rated state is maintained. The output drops to zero after a certain amount of time has passed. In a radiation irradiation test using a conventional capsule, since the sample is directly irradiated with the radiation generated from the radiation source, the sample is affected by transient radiation other than the desired irradiation conditions at the time of starting and stopping the reactor, For example, they will receive a thermal and radiation history. Therefore, the radiation irradiation test cannot be performed under desired irradiation conditions, and it is not possible to efficiently analyze the irradiation deterioration of the material with the irradiation temperature and the irradiation dose as parameters based on the test results. there were.

In the present invention, in view of the problem of the conventional capsule for irradiation test, the sample is not exposed to the thermal or radiation history at the time of starting or stopping the reactor, and the sample is irradiated under desired irradiation conditions. To be able to perform a radiation test of
It is an object of the present invention to enable efficient analysis of irradiation deterioration of materials with irradiation temperature and irradiation dose as parameters.

[0006]

According to the present invention, in a radiation irradiation test capsule, a partially cylindrical fixed shield 9a and a rotary shield 9b are provided around a sample holder 8 for accommodating a sample, and remote operation is performed. By rotating the rotation shield 9b, the radiation source side is opened and closed like a shutter. Thus, the radiation applied to the sample from the radiation source side can be interrupted at any time, and the radiation can be applied in a desired irradiation pattern.

That is, the radiation irradiation test capsule according to the present invention is provided with a sample holder 8 for holding a sample 5 and a partial cylinder which is fixedly arranged around the sample holder 8 and whose side surface is opened by a certain angle. A fixed shield 9a that shields the shaped radiation, and a rotatably arranged around the use holder 8 concentrically with the fixed shield 9a. The fixed shield 9a has a cylindrical shape with an angle wider than the open angle of the fixed shield 9a. It is characterized by having a rotary shield 9b that shields radiation and a rotating mechanism that rotates the rotary shield 9b around its central axis.

In this radiation irradiation capsule, the open side surface of the fixed shield 9a is opened and closed by rotating the rotary shield 9b. That is, when the rotation shield 9b is located on the open side surface of the fixed shield 9a, the side surface is closed and the sample holder 8 inside them is shielded from the outside. On the other hand, when the rotation shield 9b is displaced from the open side surface of the fixed shield 9a, the side surface is opened and the use holder 8 inside them is exposed to the outside. By such rotation of the rotation shield 9b, the sample 5
Can be irradiated with radiation or blocked. Therefore, when this radiation irradiation capsule is mounted inside a nuclear reactor or the like and the open side surface of the fixed shield 9a faces the radiation source side, rotation of the rotary shield 9b causes
The sample inside the sample holder 8 can be irradiated or blocked with radiation. This radiation pattern is
It can be arbitrarily changed by rotating the rotation shield 9b.

This radiation irradiation capsule is provided with an outer cylinder 3 which covers the sample holder 8, the fixed shield 9a and the rotary shield 9b, and the rotary shield 9b is rotatable about the central axis of the outer cylinder 3. It is supported. Furthermore, the outer cylinder 3
A centering member 1 for positioning the center of the sample holder 8 at a predetermined position is provided at the tip end of the, so that the sample holder 8 can be mounted at a predetermined position inside the reactor.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described specifically and in detail with reference to the drawings. The outer cylinder 3 made of stainless steel pipe and the like and the protective pipe 17 are hermetically connected in the longitudinal direction via an upper end plug 4 made of stainless steel so that their central axes coincide with each other. At the upper end of the protective pipe 17, a protective pipe 18 made of a stainless steel pipe or the like having a diameter larger than that of the protective pipe 17 is airtightly connected in the longitudinal direction so that the central axes thereof coincide with each other. A protective tube 19 made of a thin and long stainless steel tube is hermetically connected in the longitudinal direction so that the central axes thereof coincide with each other.

The lower end of the outer cylinder 3 is sealed with a lower end plug 2 made of stainless steel or the like, and a heat insulating plate 6 is attached to the upper surface of the lower end plug 2. Further, a sample holder support member 23 is attached to the upper surface of the heat insulating plate 6. On the other hand,
A centering member 1 is attached below the lower end plug 2. The tip end surface of the centering member 1 is fitted to a support pin (not shown) protruding from the bottom surface of a nuclear reactor,
A recess for supporting the lower end side of the outer cylinder 3 at a predetermined position is formed, and the central axis of this recess coincides with the central axis of the outer cylinder 3.

As shown in FIG. 2, a sample holder 8 is attached to the center of the outer cylinder 3, and a sample 5 to be subjected to a radiation irradiation test is loaded inside the sample holder 8. The sample holder 8 is loaded in the center of the outer cylinder 3 by removing the lower end plug 2 from the lower end of the outer cylinder 3, and the upper and lower ends thereof are supported by a joint 21 and the sample holder supporting member 23, which will be described later. It is placed on the central axis of the cylinder 3. A fixed shield 9a and a rotary shield 9b are attached inside the outer cylinder 3 so as to surround the sample holder 8. These shields 9a and 9b are both materials that shield radiation, such as hafnium (Hf). ) Is formed.

The fixed shield 9a has a partially cylindrical shape having an angle of 180 ° or more, and is fixed to the inside so as to coincide with the central axis of the outer cylinder 3. Illustrated fixed shield 9
a has an angle of about 200 °, and the other side surface of about 160 ° is open. The rotation shield 9b has a partially cylindrical shape whose outer diameter is smaller than the inner diameter of the fixed shield 9a and has an angle of 180 ° or more.
It is arranged inside so as to coincide with the central axis of a.
The lower end of the rotation shield 9b is rotatably supported by the lower inner peripheral wall of the outer cylinder 3 via a bearing 7, and the upper end of the rotation shield 9b is connected to a rotating mechanism via a joint 21. There is.

A heater 11 is mounted in the space between the inner surface of the outer cylinder 3 and the shields 9a and 9b. The heater 11 can heat the sample 5 in the sample holder 8 to a required temperature. it can. The rotation mechanism includes a motor 16 such as a stepping motor and a rotation introducing machine 14. The motor 16 is housed in a protection tube 18, and its shaft 20 is connected to the rotation introducing machine 14. This rotation introducing machine 14 penetrates the center of the upper end plug 4 and
It is supported by the same end plug 4. The shaft 24 of the rotation introducing machine 14 is connected to the joint 21, and the joint 21 is rotatably supported by the bearing 12 on the upper end portion of the outer cylinder 3. Therefore, the rotation shield 9 b is rotated around the central axis of the outer cylinder 3 by driving the motor 16.

As shown in FIG. 3, pipes 15, 15 ... Are pierced around the upper end plug 4 around the rotation introducing machine 14, and some of these pipes 15, 15 ... It is for ventilation between the 17 side and the outer cylinder 3 side, and a part of the other part is for drawing out wiring or the like between the protective tube 17 side and the outer cylinder 3 side.
When the capsule is mounted on the reactor, the protection tube 19 at the uppermost end is pulled out to the outside of the reactor.
Air is supplied into the outer cylinder 3 and the heater wiring is drawn out through the protective pipes 17, 18 and the pipes 15, 15.

Such a capsule for a radiation irradiation test is mounted inside a nuclear reactor or the like with the outer cylinder 3 and the protection tubes 17 and 18 arranged vertically, and the centering member 1 at the tip of the outer cylinder 3 is attached to the bottom surface of the reactor. The lower end side of the outer cylinder 3 is supported at a predetermined position in the nuclear reactor by being fitted to a support pin (not shown) protruding from. Further, the protection tube 19 is held vertically while being pulled out from the nuclear reactor. At this time, as shown by the arrow on the right side of FIG. 2, the side surface open portion of the fixed shield 9a faces the radiation source, for example, the core of the nuclear reactor.

When the nuclear reactor is started in this state, the rotary shield 9b is first stopped at the position shown in FIG. 2, and the entire sample holder 8 is closed by the shields 9a and 9b.
After that, when the operation of the nuclear reactor reaches the rated state, the motor 16 is driven to rotate the rotation shield 9b in the direction indicated by the arrow of 180 ° (or the opposite direction), and the shield 9
The radiation source side of a and 9b is opened. After that, the rotation shield 9b is rotated again by 180 °, and the entire sample holder 8 is closed by the shields 9a and 9b as shown in FIG. By doing so, the sample holder 8 side is intermittently exposed to the radiation source side, and the sample 5 therein is intermittently irradiated with the radiation.

FIG. 4 shows the output of the reactor and the sample 5 at this time.
It is an example of the graph which shows the relationship with the radiation irradiation illuminance irradiated to. In general operation of a nuclear reactor, the output of the reactor gradually increases from the start of the operation, reaches a rated state after a certain time, and the output becomes constant. After that, the output gradually decreases when the operation is stopped, and the output becomes 0 after a lapse of a certain time. In this case, when the capsule without the shields 9a and 9b is used, the sample 5 in the sample holder 8 is always irradiated with the radiation of the nuclear reactor, so the sample 5 is not overheated at the time of starting and stopping the nuclear reactor. It will also be affected by temporary radiation. For this reason, it is not possible to efficiently analyze the irradiation deterioration of the material from the test results using the irradiation temperature and the irradiation dose as parameters.

On the other hand, as described above, after the operation of the nuclear reactor reaches the rated state, the rotating shields 9b are used to shield the shields 9a, 9a.
When b is opened and the sample 5 inside the sample holder 8 is exposed to radiation, as shown in FIG. 4, the sample 5 inside the sample holder 8 can be irradiated with radiation only during the rated operation of the reactor. That is, the sample 5 can be irradiated with radiation only under constant irradiation conditions. Also, the irradiation pattern
By rotation of the rotation shield 9b by the motor 16, as shown in FIG. 4, for example, intermittent irradiation can be arbitrarily set. FIG. 5 shows a modification of the shields 9a and 9b, in which the fixed shield 9a is formed over an angle of about 225 ° and the rotary shield 9b is formed over an angle of about 155 °. In this example, the fixed shield 9a
As a result, the directivity of the sample 5 with respect to radiation increases.

[0020]

As described above, in the radiation test capsule according to the present invention, the sample can be irradiated with radiation only under desired conditions without being affected by transient radiation at the time of starting and stopping the reactor. At the same time, it becomes possible to arbitrarily set the radiation irradiation pattern on the sample. As a result, it is possible to perform a radiation irradiation test on a sample under various irradiation patterns and with desired irradiation conditions according to the purpose of the test, and to efficiently analyze the irradiation deterioration of materials using irradiation temperature and irradiation dose as parameters. You will be able to do well.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an example of a capsule for a radiation irradiation test according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is an example of a graph showing the relationship between the output of the nuclear reactor and the radiation irradiation illuminance with which the sample is irradiated.

5 is a cross-sectional plan view of another example of the radiation irradiation test capsule according to the present invention, taken along the same position as in FIG.

[Explanation of symbols]

 1 Centering member 3 Outer cylinder 5 Sample 7 Bearing 8 Sample holder 9a Fixed shield 9b Rotation shield

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kawamura 3607 Shinbori, Narita-cho, Oarai-cho, Higashi-Ibaraki-gun, Ibaraki Prefecture Inside the Oarai Research Institute, Japan Atomic Energy Research Institute (72) Inventor Nakamichi, Narita-cho, Oarai-cho, Higashi-Ibaraki-gun, Ibaraki Prefecture 3607 Shinbori, Oarai Research Institute, Japan Atomic Energy Research Institute

Claims (3)

[Claims] 1. A sample (5) to be tested by irradiation with radiation.
In a capsule for a radiation irradiation test that accommodates a sample holder (8) that holds a sample (5), and a portion that is fixedly arranged around the sample holder (8) and whose side surface is opened by a certain angle. A fixed shield (9a) that shields cylindrical radiation, and a fixed shield (9a) that is rotatably arranged concentrically with the fixed shield (9a) around the holder (8), and the opening angle of the fixed shield (9a). Radiation irradiation test characterized by having a rotary shield (9b) for shielding radiation in a wider-angle partial cylindrical shape and a rotating mechanism for rotating the rotary shield (9b) around its central axis. Capsule. 2. A sample holder (8), a fixed shield (9)
a) and an outer cylinder (3) for covering the rotation shield (9b),
The radiation irradiation test capsule according to claim 1, wherein the rotation shield (9b) is supported so as to be rotatable around the central axis of the outer cylinder (3). 3. The centering member (1) for positioning the center of the sample holder (8) at a predetermined position is provided at the tip of the outer cylinder (3).
The radiation irradiation test capsule according to.