JPS62116296A - Monitor test piece detachable device for pressure vessel of nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a monitoring test piece attachment/detachment device for a nuclear reactor pressure vessel.
In particular, the present invention relates to a monitoring test piece attaching/detaching device for a nuclear reactor pressure vessel suitable for simplifying the attachment and detachment of a monitoring test piece.

[Background of the invention]

In light water reactor pressure vessels for power generation, the core area of the reactor pressure vessel is used for the purpose of collecting data to periodically investigate and evaluate changes in the mechanical properties of the reactor pressure vessel material due to neutron irradiation. The standard stipulates that the same material as a certain member be installed as a monitoring test piece.

The monitoring test piece installed at a predetermined location is taken out from inside the reactor after a certain period of time according to a predetermined program, and is compared with mechanical property data that has not been irradiated with neutrons before reactor operation. , the existence and extent of deterioration of mechanical properties of reactor pressure vessel core area materials are being evaluated.

The monitoring test piece consisted of a tensile test piece and a Charpy impact test piece. These test pieces are monitoring test pieces for monitoring changes in mechanical properties of core region materials due to neutron irradiation, and accelerated test pieces for accelerating the predicted neutron irradiation dose over a short period of time until the end of the reactor life. It can be divided into All of these test pieces are housed in a basket and placed in a predetermined position. As shown in FIG. 9, a dryer 2, a separator 3, a jet pump 5, etc. are arranged inside the reactor pressure vessel 1, and a monitoring sample piece basket 15A for accelerated irradiation is fixed to an upper grid plate 16, and a reactor wall The monitoring test piece 15B is installed near the inner wall of the reactor pressure vessel near the reactor core.

The installation state of these test pieces will be explained based on FIGS. 10 to 14. Monitoring test piece for accelerated irradiation (bath care) 15A is
As shown in Figure 10, monitoring test pieces 15B are installed at one place inside the reactor pressure vessel, and are placed at equal intervals at an angle of 90° from the center of the reactor near the inner wall of the reactor pressure vessel. Placed.

As shown in FIGS. 11 and 12, the accelerated irradiation monitoring test pieces Basqueso 1 to 15A have aluminum foil 2 on the upper grid plate 16.
On the other hand, the furnace wall monitoring test piece Baskeso 1-15B is spot welded (23) through the bracket 1, which is suspended by the boulder 17, as shown in FIGS. 13 and 14.
A fixing method is adopted in which the holder 8 is clamped by a spring 19. The monitoring test piece must be removed from a predetermined position inside the reactor pressure vessel during reactor shutdown, based on a predetermined program and taking into account the operating period of the nuclear couplant. However, with conventional mounting mechanisms, the monitoring test piece is installed in a high radiation environment inside the reactor, making it extremely difficult for people to access the monitoring test piece installation location. Therefore, as shown in FIG. 15, the monitoring specimen basket can be taken out by operating a long ball 20 with a hook at the tip from above the flange opening of the reactor pressure vessel near the reactor well 21. work is being done.

This monitoring test piece removal work is carried out with reactor water inside the reactor pressure vessel in order to shield radiation from inside the reactor. However, the distance between the operator and the location where the monitoring test piece is installed is approximately 12 to 22 meters, and visibility is poor because the work is underwater, so underwater lighting and underwater television are used to confirm the location of the monitoring test piece. The work is done while doing the work, and the work efficiency is extremely poor. For this reason, when removing monitoring test pieces, workers are trained in advance using a mock-up that simulates the structure inside the reactor pressure vessel. However, even with such training, if the monitoring test piece basket were to fail in its removal and fall off, it would be extremely difficult to retrieve it since it is inside the reactor, and this could have a serious impact on the operation of the nuclear couplant. This work requires extreme care under radiation conditions, as it may not only cause damage to the reactor pressure vessel but also cause damage to the inside of the reactor pressure vessel.

In addition, when conventional monitoring test piece baskets are installed, after removing the monitoring test pieces, it is necessary to add new monitoring test pieces to confirm data reproducibility or to consider extending the life of the reactor pressure vessel. Even if this occurs, it is extremely difficult to reinstall the monitoring test piece because humans cannot access it.

Furthermore, since conventional monitoring test specimen baskets are mounted individually at predetermined positions, data on different neutron irradiation doses can be collected, and the mechanical properties of the material can be determined in response to neutron irradiation doses. In order to investigate trends in the amount of change, it is necessary to individually remove multiple monitoring specimen baskets.

[Purpose of the invention]

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to easily install and remove monitoring test pieces inside a reactor pressure vessel, and to easily install and remove monitoring test pieces inside a reactor pressure vessel. An object of the present invention is to provide a monitoring test piece attaching/detaching device for a nuclear reactor pressure vessel, which allows a monitoring test piece basket to be attached and removed at the same time.

[Summary of the invention]

The present invention involves laying rails in the vertical direction inside the reactor pressure vessel near the inner wall surface of the reactor pressure vessel, and moving one or more monitoring test piece baskets storing monitoring letters and test pieces on the rails. By moving the monitoring test piece basket freely along the rail, installation and removal of the monitoring test piece basket is made easy, and by connecting the monitoring test piece baskets at appropriate intervals in the longitudinal direction of the reactor core. , which allows monitoring test pieces with different neutron irradiation doses to be taken out at the same time.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings. 1st
The figure is a cross-sectional view showing an embodiment of a mechanism for attaching and detaching a monitoring test piece for a reactor pressure vessel according to the present invention when applied to a boiling water reactor pressure vessel. In Figure 1,
A dryer 2 and a separator 3 are installed inside the reactor pressure vessel 1.
, furnace piping 4, jet pump 5, etc. are arranged. A permanent rail 6 is placed in the reactor pressure vessel 1 at a position where it does not interfere with each of the above-mentioned devices. The monitoring test piece basket 7 is movably installed using the permanent rail 6 as a guide, and the monitoring test piece is stored in the monitoring test piece basket 7. In this manner, the monitoring test piece can be attached to and removed from a predetermined position within the reactor pressure vessel 1 by means of the monitoring test piece basket 7 that moves along the guide. The monitoring test piece basket 7 is installed and removed through the opening of the reactor pressure vessel flange 8. Figure 1 shows the interior of the reactor pressure vessel 1 with the monitoring test piece installed during reactor operation. It shows the condition. FIG. 2 shows the inside of the reactor pressure vessel when the monitoring test piece basket is installed and removed, with the dryer 2, separator 3, etc. in FIG. 1 removed. The permanent rail 6 can be placed at almost any position in the circumferential direction of the reactor pressure vessel 1 as long as obstacles such as the dryer support bracket 9 inside the reactor pressure vessel 1 are avoided.

In this embodiment, in order to confirm the uniformity of the distribution of the neutron irradiation amount in the circumferential direction of the reactor pressure vessel 1, permanent rails 6 are installed at several locations at equal intervals in the circumferential direction of the reactor pressure vessel. . Further, the permanent rail 6 has a structure in which a portion thereof is curved in order to avoid interference with the in-core piping 4 installed in the reactor pressure vessel 1.

FIG. 3 is a side sectional view showing how the permanent rail 6 is attached to the reactor pressure vessel 1 according to the present invention, and FIG. 4 is a front view of FIG. 3. 3 and 4, the rail support bracket 1 installed on the inner wall surface of the reactor pressure vessel 1
1, reinforcing rail supports 10 are provided at predetermined intervals in the vertical direction, and extend at both ends of the rail supports 10.

FIG. 7 shows a plurality of monitoring specimen baskets 7 connected to a permanent rail 6 at appropriate intervals.

In the core region of the reactor pressure vessel, the vertical distribution of neutron flux is high at the center of the core, as shown in FIG. 7, and becomes low above and below the center. Therefore, if the monitoring test piece baskets 7 are connected at appropriate intervals depending on the distribution of neutron flux, each monitoring test piece will receive a different amount of neutron irradiation during the same test period. It is possible to collect data on the amount of neutron irradiation.

FIG. 8(A) is a sectional view showing another embodiment of the monitoring test piece attaching/detaching device according to the present invention, and FIG. 8(B) is an enlarged view of the main part of FIG. 8(A).

In this embodiment, the permanent rail 6 is placed in the core region near the core side, and a plurality of monitoring test specimen baskets 7 are connected to the permanent rail 6 placed in this area at predetermined intervals. ing. The monitoring test piece basket 7 arranged in this manner can receive accelerated neutron irradiation that is greater than the neutron irradiation amount received by the reactor wall, so it is possible to collect data on multiple neutron irradiation doses in areas with large neutron irradiation doses. becomes.

〔Effect of the invention〕

As described above, according to the present invention, it becomes extremely easy to remove the monitoring test piece installed inside the reactor pressure vessel, and it also becomes easy to install a new monitoring test piece when the need arises. Furthermore, by connecting multiple monitoring test piece baskets at appropriate intervals in the longitudinal direction of the reactor core and installing them inside the reactor pressure vessel, data on multiple neutron irradiation doses with different neutron irradiation doses can be collected at once. Therefore, it is possible to collect data on material deterioration over time in response to changes in neutron irradiation at one time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the overall configuration of the monitoring test piece attachment/detachment device according to the present invention during reactor operation, and FIG. 2 shows the inside of the reactor pressure vessel when the monitoring test piece basket according to the present invention is attached and removed. 3 is a side sectional view showing how the permanent rail of the present invention is installed in the reactor pressure vessel (1 piece state), FIG. 4 is a front view of FIG. 3, and FIG. 5 is a monitoring test piece basket. Fig. 6 is a cross-sectional view taken along the line A-A in Fig. 5, and Fig. 7 is a front view showing the state of attachment of the monitoring specimen basket to the permanent rail. FIG. 8(A) is a sectional view showing another embodiment of the monitoring test piece attaching/detaching device according to the present invention;
Figure 8 (B) is an enlarged view of the main parts of Figure 8 (A), Figure 9 is an overall configuration diagram of the reactor pressure vessel, and Figure 10 is B-B of Figure 9.
Line sectional view, Figure 11 is an enlarged view of the main part of the monitoring test piece basket for accelerated irradiation in Figure 9, and Figure 12 is C in Figure 11.
13 is a side view 1 of the furnace wall monitoring specimen basket in FIG. 9, FIG. 14 is a front view of FIG. 13, and FIG. 15 shows the mounting state of the conventional monitoring specimen basket. FIG. ■... Reactor pressure vessel, 2... Dryer, 3... Separator, 4... In-reactor piping, 5...
Jet pump, 6...Permanent rail, 7...Monitoring specimen basket, 8...
Flange, 9...Dryer support bracket, 10...
...Rail support, 11...Rail support placket, 12...
...Wire, 13...Wheel, 14...
...stopper.

Claims (1)

[Claims] 1) Rails are laid in the vertical direction of the reactor pressure vessel near the inner wall surface of the reactor pressure vessel, and one or more monitoring test piece baskets containing monitoring test pieces are movable along the rails. A monitoring test piece attaching/detaching device for a nuclear reactor pressure vessel, which is characterized by being installed.