JP2003262697A - Shielding device for working area in reactor containment vessel, and method for repairing in-vessel structure by using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it easy to install a shielding wall for reducing radiation exposure in the repairing and repair work in a reactor pressure vessel (RPV). <P>SOLUTION: The shielding wall in an RPV skirt 11 is constituted by putting shielding body blocks 20 on shielding body support pedestals 19 mounted on CRD housings 9, and a shielding wall in a pedestal 12 consists of shielding plates 26 mounted on a CRD housing flange 9a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor containment vessel for repairing and repairing reactor internals such as a neutron flux measuring device (ICM) and a control rod drive mechanism (CRD) in the reactor containment vessel. TECHNICAL FIELD The present invention relates to a work area shield device that shields a work area inside from radiation, and a method for repairing internal structures of a reactor using the same.

[0002]

2. Description of the Related Art In a nuclear power plant, a high-dose work area where repair and repair work is carried out in a reactor containment vessel (PCV) and a reactor pressure vessel (RPV) in service, is a lead plate or a lead hair mat. The exposure dose is reduced by using a shielding device that is constructed by binding the scaffold to a support. However, in a narrow working space within the RPV or PCV, the work of binding the lead plate or the lead bristle mat to the support of the scaffolding material to construct the shielding device is cramped and the work efficiency is poor.

Therefore, Japanese Utility Model Laid-Open No. 62-111583 proposes a control rod drive mechanism housing support fitting as shown in FIG. 11 (first prior art). This support fitting is a grid plate 41 placed under the CRD.
A support bar 42 supporting both ends thereof, a support beam 43 arranged below the PCV and connected to an inner wall of the pedestal (both not shown), and a support beam 4
3 and a suspension rod 44 connecting the support bar 42.

A shield plate 45 is supported between the lower ends of the suspension rods 44. The shield plate 45 has a dimension longer than the interval between the adjacent suspension rods 44, both ends thereof are fixed by the two suspension rods 44, and the adjacent suspension rods 44 are mounted in a vertically stacked relationship.

In Japanese Utility Model Publication No. 62-91291,
A radiation shielding mechanism for a PCV pedestal as shown in FIG. 12 has been proposed (second prior art). This shield mechanism has a structure in which a radiation shield 55 is provided to block the central space 54 of the PCV pedestal 53 in a state in which a large number of CRD housings 52 projecting vertically from the RPV 51 are inserted so as to be vertically movable. ing.

The radiation shield 55 is composed of upper and lower iron plates 5 each having a through hole through which each CRD housing 52 is inserted.
6 and a neutron beam shielding layer 57 made of boron or the like interposed between the iron plates 46. 58 is CR
D It is a grating used as a scaffold for replacement work.

Further, Japanese Patent Laid-Open No. 56-40788 proposes a CRD exchange device as shown in FIGS. 13 to 15 (third prior art). 13 is a cross-sectional plan view of the carry-in / out port of the CRD exchanging device, FIG. 14 is an enlarged view of FIG. 13A, and FIG. 15 is a front view of the arrow B of FIG.

This CRD exchanging device is provided in a space below a PCV (not shown) in a pedestal 61, and comprises a turning moving device 62, a CRD attaching / detaching device 63 and a CRD handling device 64 mounted thereon. Has been done.

The swing moving device 62 is mounted on a circular rail 65, a platform 66 is provided at an appropriate position, and a shield chamber 67 is formed at an end of the platform 66. The shield chamber 67 is formed by attaching a shield plate 69 supported by four columns 68 to the ceiling. For maintenance and inspection of the CRD replacement device in the pedestal 61, or for visual confirmation during CRD replacement work, the platform 6
The operator stands by in the shielding room 67 when the work on 6 is completed or when the next setup or the like is performed. Reference numeral 70 in FIG. 13 denotes a carry-in / out port provided in the pedestal 61.

Furthermore, Japanese Patent Laid-Open No. 7-55981 proposes a support for a CRD housing as shown in FIGS. 16 and 17 (fourth prior art). 16 is C
FIG. 17 is a plan view of the RD housing support, and FIG. 17 is a side view in which a part of the support is sectioned.

As shown in FIG. 17, this housing support is provided with a radiation shield cup 73 for accommodating the bottom 72 of each control rod drive device 71 and a cup support rod 74 provided on the peripheral surface of the shield cup 73. And a hanger rod 77 to which the support rod 75 is attached via a hub 76, and the like. An opening 79 through which an electric cord 78 (see FIG. 17) of the control rod drive device 71 is inserted is formed at the bottom of the shielding cup 73.

As shown in FIG. 16, a plurality of (two in the illustrated example) shield cups 73 are provided on the peripheral surface of the shield cup 73 at positions where the cup support rods 74, 74 face each other. Support rods 7 arranged at the front and back with the clip in between
It is supported by 5,75.

[0013]

In the case of the control rod drive mechanism housing support fitting according to the first prior art shown in FIG. 11, for example, the CRD housing 40a or 40b is used.
When replacing the above, since the shielding plate 45a below it is mounted on the shielding plates 45b and 45c on both sides thereof, the shielding plate 45a and the shielding plates 45b and 45c on both sides thereof in total are 3 It is necessary to remove the one shield plate 45. Therefore, the other shield plate 45 near the exchange place must be removed, the effect of shielding the radiation near the exchange place is reduced, and the extra shield plate 4 is removed.
There is a problem that it takes time to remove and install 5b and 45c.

In the case of the radiation shielding structure according to the second prior art shown in FIG. 12, the radiation shielding member 55 is large enough to cover the space 54 of the pedestal 53, resulting in high cost. Moreover, since it is necessary to form through holes through which a large number of CRD housings 52 are inserted respectively at predetermined positions of the radiation shield 55, the production of the radiation shield 55 and its attachment are complicated, and especially the radiation shield 55 is In the case of the two iron plates 56, 56 and the neutron beam shielding layer 55 which is filled between the iron plates 56 and 56 and surrounds the outer periphery of each CRD housing 52, their production and their attachment are very complicated.

In the case of the CRD exchanging device according to the third prior art shown in FIGS. 13 to 15, maintenance of the CRD exchanging device,
When working on the platform 66 for inspection and visual confirmation during CRD replacement work, since the worker exits the shield room 67 and performs a predetermined work, there is a problem that radiation exposure during that time is inevitable.

In the case of the CRD housing support according to the fourth prior art shown in FIGS. 16 and 17, the control rod drive device 71 shown in FIG. 16 is covered with, for example, a shield cup 73a.
Since the shield cup 73a is supported by the support rod 75a and the support rod 75b, it is necessary to remove both support rods 75a and 75b when exchanging. However, since the support rods 75a and 75b also support the shield cups 73b to 73f around them in addition to the shield cups 73a, these shield cups 73b to 73f are also removed. Therefore, another shield cup 73 near the replacement site
There is a problem in that the removal of b to 73f is unavoidable, the effect of shielding radiation near the replacement place is reduced, and it takes time to remove and install the extra shielding cups 73b to 73f.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to easily install a shielding device only at a necessary portion in repair / repair in a high dose and narrow working space in RPV or PCV. (EN) Provided is a work area shield device in a nuclear reactor containment vessel, which enables safe and efficient work, and a method of repairing a reactor internal structure using the same.

[0018]

In order to achieve the above-mentioned object, the present invention provides an internal reactor containment vessel for repairing internal structures such as ICM and CRD. It is intended for work area shielding devices that shield the work area from radiation.

The first means of the present invention is the above-mentioned repair /
The shield support is detachably attached to the side of the structure to be repaired, a predetermined number of shield blocks are placed on the shield support, and the shield support and shield blocks are repaired and repaired alternately. It is characterized in that a shielding wall is formed by installing it on the side of an object.

According to a second aspect of the present invention, in the first means, the shield support base has a groove portion, and at least one of the shield blocks is placed in the groove portion. To do.

A third means of the present invention is the first means or the second means, wherein a plurality of shield blocks are stacked on one shield support base, and the shield blocks are covered by other shields. It is characterized in that a lateral shift prevention portion that engages with the body block is provided.

According to a fourth aspect of the present invention, in any one of the first to third means, a part of the structure to be repaired / repaired is provided at one end of the shield support base. A hooking arm for locking is provided, and a support member for mechanically sandwiching a part of the structure to be repaired / repaired is provided at the other end of the shield support to repair the hooking arm. Hook a part of the structure to be repaired,
By sandwiching the other part of the structure to be repaired or repaired by the support member, the shield supporter is detachably attached to the side surface of the structure to be repaired or repaired.

A fifth means of the present invention is the shield means for the structure to be repaired / repaired according to the fourth means, so that the support member of the shield support is located on the outer peripheral side of the work area. It is characterized by being attached.

A sixth means of the present invention comprises a shielding plate applied to each flange of the structure to be repaired / repaired, and a mounting member for removably mounting the shielding plate to the flange. A shield wall is formed by attaching the shield plate.

A seventh means of the present invention is that the shield support is detachably attached to the side surface of the structure to be repaired / repaired, a predetermined number of shield blocks are placed on the shield support, and the shield is placed on the shield. A body support and shield blocks are alternately installed on the side of the structure to be repaired / repaired to form a shielding wall, and the shielding plate applied to each flange of the structure to be repaired / repaired and the shielding plate It comprises a mounting member which is detachably mounted on the flange, and the shielding wall is formed by mounting the shielding plate on each flange.

According to an eighth aspect of the present invention, the work area shielding device according to any one of the first to seventh means is installed in a pedestal, and the repair work of the reactor internal structure is performed in the pedestal. It is characterized by performing the operation and then removing the work area shielding device.

A ninth means of the present invention is to install the work area shielding device according to any one of the first to seventh means in a pedestal and a reactor pressure vessel skirt, and in the pedestal, the reactor is installed. Repairing internal structures,
After that, the work area shielding device is removed.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 10 as an example of replacement work of a neutron flux measurement device (ICM) housing for repair / repair work of a reactor internal structure. And explain.

FIG. 2 is a vertical sectional side view of the RPV and the internal structure of the boiling water reactor. The RPV 1 contains a dryer 2, a separator 3 and a shroud 4, and an upper lattice plate 5 and a core support plate 6 for supporting fuel are attached to the shroud 4. At the bottom of the RPV 1 (lower mirror part), an ICM housing 8 connected to the ICM guide tube 7 and a CR
The D housing 9 penetrates. The ICM housing 8 has an ICM housing flange 8a at its lower end,
The D housing 9 has a CRD housing flange 9a at its lower end.

FIG. 3 is a vertical sectional side view of the structure inside the RPV 1 and the PCV 10. The RPV 1 is formed by connecting the RPV skirt 11 to the top opening step 1 of the pedestal 12 of the PCV 10.
It is installed at 0a. The ICM housing 8 and the CRD housing 9 reach the inside of the pedestal 12 through the heat insulating material 13 that closes the bottom of the RPV 1 and the top opening of the pedestal 12. Heat insulation material 1 inside the RPV skirt 11
4, a grating plate 15 is laid along the step 10a between the inside and the CRD housing 9.

In the pedestal 12, an ICM housing exchanging device 17 mounted on a platform 16 is installed for exchanging the ICM housing.

For repairing and repairing the internal structure of the nuclear reactor as described above, a long apparatus is installed from inside the pedestal 12 by RPV.
This is done by inserting into 1. Replacing the ICM housing 8 eliminates the guide for inserting a long device from the pedestal 12 after pulling out the lower ICM housing 8b.
Install an insertion guide inside.

FIG. 1 shows an ICM in such a nuclear reactor.
It is a flowchart of the replacement work of the housing 8. In step 1, before draining water in RPV1, pedestal 1
Install a shield inside 2 and install a shield wall. When installing the shield inside the pedestal 12, it is necessary to remove the CRD housing support in advance in order to prevent interference. Further, since the nuclear instrumentation cable hangs down from above after the CRD is removed, the shielded body is cured by binding it to the CRD housing 9 so that it does not interfere with the attachment of the shielded body. Attach to the CRD housing flange 9a.

In step 2, the RPV skirt 11
Install a shield to install a shield wall inside.
To install this shield, enter the RPV skirt 11 through the manhole of the heat insulating material 13 and then use the grating plate 1.
5 Move on top and attach the shield to the shield wall installation part. The shield is attached to a structure such as the CRD housing 9 in the PCV 10.

In step 3, all the water in the RPV 1 is drained, and the ICM housing 8 is exchanged in preparation for exchange in the air environment. In step 4, the processing machine is inserted from the lower part of the furnace into the ICM housing 8 to be replaced, and the ICM housing 8 is cut by the lower mirror portion of the RPV 1 to prepare for withdrawal.

In step 5, a jack is attached from the lower part of the furnace to the flange 8a of the ICM housing 8 to be replaced, and the lower ICM housing 8b is located below the cut portion.
Forcibly pull out and carry out. In step 6, a jig / machining machine for fixing the ICM guide tube 7 connected to the ICM housing 8 from the lower part of the furnace is inserted into the ICM guide tube 7 from the upper CRD housing 8c, and the lower end of the ICM guide tube 7 is cut off. In step 7, the separated ICM guide tube 7 and upper ICM housing 8 are taken out of the RPV 1 and carried out.

In step 8, the processing machine is inserted from the bottom of the furnace, and the build-up welded portion (the portion where the ICM housing 8 to be replaced is fixed by welding) at the bottom of the RPV 1 is completely removed by machining. In step 9, the welding machine is carried in from the upper part of the furnace, and a new build-up seat is formed in the build-up welded portion removed in step 8. In step 10,
A processing machine is inserted into the RPV 1 from the lower part of the furnace to shape the newly formed build-up seat. In step 11, the lower end of the ICM guide tube 7 is groove-processed by the processing machine inserted into the RPV 1 from the lower part of the furnace.

In step 12, a new ICM housing 8 is inserted from the bottom of the furnace. In step 13, a welding machine is inserted into the ICM housing 8 from the lower part of the furnace, and the new ICM guide tube 8 and the remaining ICM housing 7 are welded from the inner surface to be joined. In step 14, the welding machine is loaded into the RPV1 from the upper part of the furnace and the RPV1
The new ICM housing 8 and the new ICM housing 8 are welded (J welded) to each other at the build-up seat to be joined.

In step 15, water is poured into RPV1.

In step 16, RPV skirt 1
Remove the shield inside 1 and dismantle it. This removal procedure is the reverse of the attachment procedure in step 2.
In step 17, the shield inside the pedestal 12 is removed and the shield wall inside the pedestal is disassembled. This removal procedure is the reverse of the attachment procedure in step 1. In step 18, a pressure resistance test of the welded portion of the ICM housing 8 is performed, and if there is no abnormality, the replacement work is completed.

Most of the replacement work of the ICM housing 8 is a work in the lower part of the furnace, and the work space is in the RPV skirt 11 or the pedestal 12 shown in FIG.

When replacing the ICM housing 8, RPV1
Since the working space in the RPV skirt 11 and the pedestal 12 becomes a high dose area in order to drain the water inside, by installing the shield wall inside the pedestal and the shield wall inside the RPV skirt before draining water inside the RPV 1, Prevent exposure during installation work.

FIG. 4 is an exploded perspective view of the shield body constituting the shield wall installed in the RPV skirt 11. The shield according to the present embodiment mainly includes a shield support 19 that functions as a mounting member and a shield block 20 that is supported by the shield support 19 and that functions as a shield.

The shield support 19 is made of carbon steel and has a U-shaped cross section with the flange facing upward.
9a, a rear wall 19b, and a bottom wall 19c connecting the front wall 19a and the rear wall 19b, and having an outer width of 100 m, for example.
m, inner width 80 mm, height 45 mm, length 1000 mm.

The shield block 20 has, for example, five sides.
It is a square rod-shaped carbon steel having a length of about 1000 mm and a square of 0 mm. 30 mm in length and 20 m in width at a position 200 mm inside from both ends of the shield block 20.
A lateral shift prevention portion 21 having a thickness of 6 mm and a thickness of 6 mm is welded to the side surface of the shield block 20 so as to project downward or upward by 20 mm.

A plurality of shield blocks 20 are stacked and placed in the inner groove portion of the shield support 19.
The shield support 19 also functions as a part of the shield.
The front wall 19a of the shield support 19 has a function of preventing lateral displacement of the shield block 20 at the bottom.

On the rear wall 19b of the shield support base 19, a pair of two supports 22 for fixing it to the CRD housing 9 and a hooking arm 23 having a thickness of about 15 mm are welded. There is. The shield support 19 is attached by positioning the arm 23 by hooking the arm 23 from the outside of one of the CRD housings 9, and using the support 22 to position the other one.
The three CRD housings 9 are sandwiched, and the three mounting bolts 24 screwed to the support 22 are clamped and fixed so that the two mounting bolts 24 are attached to the CRD housing 9 in the order of the outer two and the inner one. A protective cap 25 is fitted on the tip of each mounting bolt 24 to prevent the CRD housing 9 from being scratched and to prevent it from slipping. In the present embodiment, the support 22, the bolt 24, and the protective cap 25 constitute a support member. The shield support 19 is attached in a horizontal state. FIG. 7 shows a planar state in which the shield support 19 is attached in this manner.

FIG. 5 is a perspective view showing a shielding wall constructed by mounting a shielding body in the RPV skirt 11. In this shield wall, the shield supporter 19 is attached to the CRD housing 8 as described above, and the shield block 20 is stacked on the shield supporter 19 to be assembled successively. When stacking the shield blocks 20 on the shield support 19, the lateral shift prevention portion 21 welded to the side surface of the shield block 20 is used to perform positioning and fall prevention.

FIG. 6 is a front view [the same figure (a)] and a side view [the same figure (b)] of the shielding wall installed in the RPV skirt 11. The shielding wall is constructed as follows.

First, the shield supporter 19 of the first stage is positioned at the height of the upper surface of the grating plate 15 to the limit of CR.
The shield support 19 is attached to the CRD housing 9 by attaching it to the D housing 9 and tightening the attachment bolts 24 screwed to the support 22. A plurality of shield blocks 20 (three in this embodiment) are stacked in the inner groove of the shield support 19.

At the time of stacking the shield blocks 20, the lateral deviation prevention portion 21 is stacked up to the first and second tiers, and the third tier is stacked downward. Side slip prevention unit 2
When the shield block 20 in the third stage with 1 facing downward is stacked on the shield block 20 in the second stage, the lateral shift prevention portions 21 of the upper and lower shield blocks 20 interfere with each other, so the shield block in the third stage is blocked. 20 is slightly shifted in the longitudinal direction to avoid interference. Such a state is clearly shown in FIG.

On the upper surface of the uppermost shield block 20 of the first stage, a gap of about 10 mm to 20 mm is formed, and in the same manner, the second stage shield support 19 is attached and the shield blocks 20 are stacked. By repeating the procedure, the shielding body blocks 20 are piled up to the position just near the bottom of the RPV 1 to form a shielding wall.

FIG. 7 is a cross-sectional plan view showing an arrangement state of the shield walls installed in the group of the ICM housing 8 and the CRD housing 9 in the RPV skirt 11 to prevent exposure when replacing the ICM housing.

In this embodiment, the ICM housing 8d is used.
Is an example of an ICM housing to be replaced, in which a shield wall is formed so as to surround the work area when working in the vicinity thereof so as to be isolated from other ICM housings 8 and CRD housings 9 serving as radiation sources.

In this embodiment, the support 22 side of the shield support 19 is arranged on the outer peripheral side of the RPV 1 so that the shield support 19 can be attached to the CRD housing 9 and the tightening work can be easily performed with the bolts 24. it can.

FIG. 8 is a perspective view of a shield for forming a shield wall separating the work area in the pedestal, and FIG. 9 is a perspective view of the shield attached to the CRD housing flange. This shielding wall is, as shown in FIG.
It is formed by attaching the shield to the CRD housing flange 9a.

The shield of the present embodiment comprises a shield plate 26 that shields, and a plurality of pairs of hook bolts 27 and hooks 28 that function as mounting members. The shield plate 26 is formed of a carbon steel plate having a thickness of about 30 mm in a quadrangular shape, and has a CRD housing flange 9a.
An arcuate notch 26b is provided to avoid interference between the hole 26a for connection with the CRD housing flange 9a and the adjacent ICM housing flange 8a.

The shield plate 26, as shown in FIG.
The hook bolt 27 and the hook 28 hook the CRD housing flange 9a so as to be sandwiched between the shield plate 26 and the CRD housing flange 9a.

FIG. 10 shows a pedestal 12 as a work area.
FIG. 3 is a cross-sectional plan view [FIG. (A)] and a side view [FIG. (B)] showing a shielding wall installed by attaching a shielding plate 26 so as to isolate the inside from a group of the ICM housing 8 and the CRD housing 9. .

The shield wall in the pedestal in this embodiment is an IC to be exchanged immediately above the work area.
CRD housing flange 9 near the M housing 8d
It is formed by attaching the shield plate 26 to a with no gap. A notch 26b provided to avoid interference with the adjacent ICM housing flange 8a and CRD housing flange 9a when the shield plate 26 is attached.
The shielding plate 26 is attached and positioned according to the shape (see FIG. 8). The hook bolt 27 has a length of about 70 mm so that the shield plate 26 can be attached to form a shield wall without removing the CRD restrent 29 [see (b) in the figure].

According to the present invention, the shielding wall for reducing the exposure in the work in the vicinity of the high radiation source for repair / repair of the reactor containment vessel and the internal structure of the reactor can be easily provided only at a necessary portion. It can be easily configured.

[Brief description of drawings]

FIG. 1 is a flowchart of an ICM housing replacement work in an embodiment of the present invention.

FIG. 2 is a vertical sectional side view showing a reactor pressure vessel and a reactor internal structure of a boiling water reactor.

FIG. 3 is a vertical sectional side view showing an entry work area for ICM housing replacement.

FIG. 4 is an exploded perspective view of a shield for constructing a shield wall that is installed to shield the work area within the RPV skirt.

FIG. 5 is a perspective view showing a shield wall installed in the RPV skirt.

FIG. 6 is a perspective view showing a shielding wall installed in the RPV skirt.

FIG. 7 is a cross-sectional plan view showing an arrangement state of a shielding wall installed in an RPV skirt.

FIG. 8 is a perspective view of a shield for forming a shield wall installed so as to shield a work area in the pedestal.

FIG. 9 is a perspective view showing a state in which the shield is attached to the CRD housing flange in order to install the shield wall inside the pedestal.

FIG. 10 is a cross-sectional plan view and a side view showing a shielding wall set in a pedestal.

FIG. 11 is a side view of a control rod drive mechanism housing support fitting according to a first conventional technique.

FIG. 12 is a cross-sectional view of a radiation shielding mechanism in a PCV pedestal according to a second conventional technique.

FIG. 13 is a cross-sectional plan view of a carry-in / out port of a CRD exchanging device according to a third conventional technique.

FIG. 14 is an enlarged view of FIG. 13A.

FIG. 15 is a front view taken along the arrow B of FIG.

FIG. 16 is a plan view of a CRD housing support according to a fourth conventional technique.

FIG. 17 is a side view in which a part of the support is sectioned.

[Explanation of symbols]

1 Reactor pressure vessel (RPV) 2 dryer 3 separator 4 shrouds 7 ICM guide tube 8 ICM housing 8a ICM housing flange 8d ICM housing to be replaced 9 CRD housing 9a CRD housing flange 10 Reactor containment vessel (PCV) 11 RPV skirt 12 pedestal 19 Shield support 20 Shield block 22 Support 23 arms 26 Shield plate 27 hook bolt 28 hooks 29 CRD Restrent

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryo Sato             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division

Claims (9)

[Claims] 1. Repairing the internal structure of the reactor in the containment vessel
In a work area shield device for shielding the work area in the reactor containment vessel from radiation for repair, a shield support base is detachably attached to the side surface of the structure to be repaired / repaired, and the shield support base is attached. A shield wall is formed by placing a predetermined number of shield blocks on top and alternately installing this shield support and shield blocks on the side of the structure to be repaired / repaired to form a shield wall. Work area shielding device. 2. The work area shielding device according to claim 1, wherein the shield support has a groove, and at least one of the shield blocks is placed in the groove. A work area shielding device in the containment vessel. 3. The work area shield apparatus according to claim 1 or 2, wherein a plurality of shield blocks are stacked on one shield support, and the shield blocks are combined with other shield blocks. A work area shielding device in a reactor containment vessel, which is provided with a lateral slip prevention portion for locking. 4. The work area shielding apparatus according to claim 1, wherein a hook for locking a part of the repair / repair target structure to one end of the shield support base. Arm is provided, and a support member for mechanically sandwiching a part of the structure to be repaired / repaired is provided at the other end of the shield support, and the structure for repairing / repairing the hooking arm is provided. Characterized in that the shield supporter is detachably attached to the side surface of the repair / repair target structure by hooking a part of the other part of the repair / repair target structure by the support member. A work area shielding device in the containment vessel. 5. The work area shield apparatus according to claim 4, wherein the shield support base is attached to the repair / repair target structure so that the support member of the shield support base is located on the outer peripheral side of the work area. A work area shielding device in a containment vessel. 6. Repairing the internal structure of the reactor in the reactor containment vessel
In a work area shield device for shielding the work area in the reactor containment vessel from radiation for repair, a shield plate applied to each flange of the structure to be repaired / repaired, and the shield plate can be detached from the flange A work area shield device in a reactor containment vessel, characterized in that a shield wall is formed by attaching the shield plate to each flange. 7. Repairing the internal structure of the reactor inside the containment vessel
In a work area shield device for shielding the work area in the reactor containment vessel from radiation for repair, a shield support base is detachably attached to the side surface of the structure to be repaired / repaired, and the shield support base is attached. A predetermined number of shield blocks are placed on top of this, and a shield wall is formed by alternately installing this shield support and shield blocks on the sides of the structure to be repaired / repaired. The reactor containment vessel, characterized in that it comprises a shield plate applied to the flange of and a mounting member for removably attaching the shield plate to the flange, and a shield wall is formed by attaching the shield plate to each flange. Work area shielding device inside. 8. A work area shielding device according to any one of claims 1 to 7 is installed in a pedestal,
A method for repairing the internal structure of a nuclear reactor, which comprises repairing the internal structure of a nuclear reactor in a pedestal and then removing the work area shielding device. 9. The work area shielding device according to any one of claims 1 to 7 is installed in a pedestal and a reactor pressure vessel skirt, and repair work of a reactor internal structure is performed in the pedestal. , Then, the method for repairing the internal structure of a nuclear reactor, characterized in that the work area shielding device is removed.