JP2012117946A - Nuclear reactor building of nuclear power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a lay-down space cannot be secured and workability around a nuclear reactor well is inhibited when maintenance of large equipment is executed since a cask decontamination pit is installed beside a cask pit of a used fuel pool at an operation floor of a nuclear reactor building, and in addition, man-hour of a maintenance work increases since an XY direction crane cannot be used in transfer of an MSIV/SRV chamber in the perpendicular direction since an MSIV/SRV wrapping chamber is narrow in the conventional case.SOLUTION: A nuclear reactor well side of a large object carrying-in port is secured as a lay-down space with sufficient area by transferring a cask decontamination pit conventionally installed beside a cask pit of a used fuel pool and on the front side of the large object carrying-in port viewed from the nuclear reactor well to the opposite side of the large object carrying-in port. In addition, an XY crane is installed in an MSIV/SRV wrapping chamber widely secured by transferring the cask decontamination pit to the opposite side of the large object carrying-in port viewed from the nuclear reactor well.

Description

  The present invention relates to a reactor building structure of a nuclear power plant with improved workability of an operation floor.

  Conventionally, in a nuclear power plant, a cask is used as a container for storing and transporting spent fuel taken out from the core. The cask is usually a heavy container having a cylindrical shape with a diameter of about 3 m and a length of about 10 m, for example, a sealed container made of stainless steel. In order to protect workers from radiation exposure, loading of spent fuel into the cask is performed in a cask pit provided at one corner of the spent fuel pool. Since the operation of loading the spent fuel into the cask is performed underwater, the surface of the cask is contaminated with pool water from the spent fuel pool. For this reason, a cask decontamination pit is installed to clean the surface of the cask taken out from the cask pit to the extent that it can be carried out of the nuclear power plant.

  FIG. 3 shows the state of the laydown (temporary placement) space of the operation floor A provided in the upper part of the conventional reactor building 10. The laydown space 9 in which large equipment on the operation floor A of the reactor building 10 can be laid down is about 30 m × 10 m. The laydown space 9 is provided on the side of the reactor well 8 and the spent fuel pool 6. Here, a cask pit 5 is provided in a part of the spent fuel pool 6, and a large material entrance 7 for carrying various devices and the like from the lower floor is installed in the vicinity of the cask pit 5. The cask decontamination pit 1 is arranged on the front side of the large material entrance 7 when viewed from the reactor well 8 in the substantially central portion of the operation floor A. In this case, since the cask decontamination pit 1 is arranged in the vicinity of the reactor well 8, sufficient laydown space is not secured when large-scale equipment is maintained on the operation floor A. The workability of was reduced.

  FIG. 4 shows a lower floor B arranged one floor below the operation floor A. The lower floor B includes an MSIV / SRV wrapping chamber 2 for performing maintenance and inspection of the main steam isolation valve (MSIV) and the main steam relief valve (SRV), and is disposed below the operation floor A. The MSIV / SRV wrapping chamber 2 is installed on the lower floor B, and has a space of about 40 m × about 8 m. However, since the lower part of the cask decontamination pit 1 of the operation floor A protrudes from the ceiling of the MSIV / SRV wrapping chamber 2, the width of the MSIV / SRV wrapping chamber 2 that can be used for actual work is narrowly limited to about 5 m. The monorail 3 is installed in a straight line, and the electric chain block 4 is installed to perform maintenance work.

  An interior partition wall 11 is installed in the MSIV / SRV wrapping chamber 2. This is because the cask decontamination pit 1 is installed on the operation floor A, which is the upper floor, and the area with poor workability is used as the storage space due to the lower part of the cask decontamination pit 1 protruding from the ceiling in the MSIV / SRV wrapping room. It is installed for the purpose of partitioning the room for use.

  In a reactor building having a spent fuel pool 6 having a longitudinal dimension of about 30 m to increase the fuel storage capacity, the conventional cask decontamination pit 1 is located on the front side of the large-size inlet 7 when viewed from the reactor well 8. Had been placed in.

  In Patent Document 1, since the crane is installed when disassembling the SRV in the reactor containment vessel, it is not necessary to consider exceeding the peak of the SRV when carrying out the SRV. It is disclosed that it can be lowered. However, a configuration in which an XY crane movable in a horizontal plane is installed in the MSIV / SRV wrapping chamber is not disclosed.

  Patent Document 2, Patent Document 3, and Patent Document 4 all disclose that a cask decontamination pit is installed in the vicinity of a reactor well in a conventional reactor building. No particular mention is made of securing the laydown space by arranging the reactor well away from the reactor well.

  The purpose of the present invention is to improve work efficiency at the time of regular inspection of the operation floor by relocating the cask pit or cask decontamination pit, and to improve work efficiency at the time of regular inspection by installing an XY crane in the MSIV / SRV wrapping room To do.

JP-A-9-222490 JP 63-274897 A JP 62-118296 A Japanese Patent Laid-Open No. 9-5492

  Conventionally, the cask decontamination pit has been installed close to the cask pit of the spent fuel pool, so there is not enough laydown space when maintaining large equipment on the operation floor, impeding workability. . Further, in the MSIV / SRV wrapping room, the width of the room is narrow, so a monorail is installed on the upper part and an electric chain block is installed to perform maintenance work. During the maintenance work, it is necessary to move the MSIV and SRV in a direction perpendicular to the monorail, but there is a problem that the number of maintenance work increases because the upper electric chain block cannot be used for the movement in the perpendicular direction.

  The present invention relates to a nuclear reactor well, a spent fuel pool having a cask pit, a large material inlet provided in the vicinity of the spent fuel pool, and a cask decontamination for decontaminating the cask carried from the cask pit. In the reactor building having a pit and an operation floor having a laydown space on the side of the spent fuel pool and a laydown space for temporary placement of equipment during a periodic inspection work, the cask decontamination pit and the large-sized object are carried in A mouth is disposed at an end of the operation floor, and a continuous laydown space is secured to the side of the reactor well and the spent fuel pool.

  Further, in the reactor building, the cask decontamination pit is arranged on the reactor well side with respect to the large material entrance.

  Further, in the reactor building, the cask decontamination pit is arranged on the opposite side to the reactor well with respect to the large material carrying-in port.

  In the reactor building, an XY crane is installed on the ceiling of the MSIV / SRV wrapping disposed on the lower floor below the operation floor.

  In the reactor building, a space for installing an XY crane in the MSIV / SRV wrapping chamber is secured by removing an indoor partition wall.

  The present invention temporarily holds equipment during a periodic inspection operation, a nuclear reactor well, a spent fuel pool having a cask pit, a large-sized material inlet provided close to the spent fuel pool, a cask decontamination pit In a reactor building with an operation floor that has a laydown space on the side of the reactor well and the spent fuel pool, a cask decontamination pit and a large loading port are arranged at the end of the operation floor, and the reactor well and the above-mentioned use By securing a continuous laydown space on the side of the spent fuel pool, a sufficient laydown space on the operation floor can be secured, and workability during equipment maintenance can be improved.

  Also, by securing a wide MSIV / SRV wrapping chamber, installing an XY crane in the MSIV / SRV wrapping chamber, and setting the entire MSIV / SRV wrapping chamber as the operating range of the crane, MSIV and SRV can be installed at any position in the room. It can be moved and workability can be improved.

The top view which shows the operation floor of the reactor building of this invention The top view which shows the lower floor of the reactor building of this invention Plan view showing the operation floor of a conventional reactor building Plan view showing the lower floor of a conventional reactor building

  Embodiments of the present invention will be described below based on examples.

  FIG. 1 is a plan view showing a laydown state of an operation floor of a reactor building according to the present invention. A cask pit 5 is installed in a part of the spent fuel pool 6, and a large material entrance 7 is installed in the vicinity of the cask pit 5. The cask decontamination pit 21 is newly disposed on the side opposite to the large material inlet 7 when viewed from the reactor well 8. In this case, as can be seen by comparing with the operation floor of the conventional reactor building of FIG. 3, a certain continuous laydown space 29 of about 40 m × 10 m wider than the conventional one is secured on the side of the reactor well 8. Workability during maintenance can be improved.

  Here, FIG. 1 shows a case where the large carry-in entrance 7 remains at the conventional position, and the cask decontamination pit 21 is newly moved near the wall at the end of the operation floor A. The large material entrance 7 may be moved together. Alternatively, the large carry-in entrance 7 may be moved near the end of the operation floor A, and the cask decontamination pit 21 may be provided on the reactor well 8 side in the vicinity thereof. In this case as well, a certain continuous and wider laydown space 29 is secured, the moving distance from the cask pit 5 to the cask decontamination pit 21 is shortened, and the curing work to prevent contamination of the floor of the operation floor A is facilitated. Become.

  FIG. 2 shows the lower floor B containing the MSIV / SRV wrapping chamber 12 of the reactor building according to the invention. In this case, the cask decontamination pit 21 is disposed on the opposite side of the large material inlet 7 as viewed from the reactor well 8 as described above. Therefore, since the lower part of the cask decontamination pit 1 and the MSIV / SRV wrapping chamber 2 are arranged at positions that do not interfere with each other in a plane, the indoor partition wall 9 that was in the MSIV / SRV wrapping chamber 2 in the conventional example becomes unnecessary, This can be removed. Therefore, the size of the MSIV / SRV wrapping chamber 2 can be secured about 40 m × about 8 m. By installing the XY crane 13 on the ceiling of the MSIV / SRV wrapping chamber 2, the MSIV / SRV wrapping chamber 2 is installed on the entire room by the crane. As a result, the workability can be greatly improved.

5. Cask pit
6 ... spent fuel pool
7 ... Large port
8 ... Reactor well
9 ... Room partition wall
21 ... Cask decontamination pit 22 ... MSIV / SRV wrapping room
23 ... XY crane 29 ... laydown space A ... operating floor B ... lower floor

Claims (5)

A nuclear reactor well, a spent fuel pool having a cask pit, a large material inlet provided in the vicinity of the spent fuel pool, a cask decontamination pit for decontaminating the cask carried from the cask pit, In the reactor building having an operation floor having a laydown space for temporary placement of equipment at the time of inspection work on the side of the reactor well and the spent fuel pool,
The reactor building characterized in that the cask decontamination pit and the large-size carry-in entrance are arranged at an end of the operation floor, and a continuous laydown space is secured to the side of the reactor well and the spent fuel pool. .   The reactor building according to claim 1, wherein the cask decontamination pit is disposed on a reactor well side with respect to the large-size entrance.   The reactor building according to claim 1, wherein the cask decontamination pit is disposed on the opposite side to the reactor well with respect to the large material entrance.   The reactor building according to any one of claims 1 to 3, wherein an XY crane is installed on a ceiling of an MSIV / SRV wrapping disposed on a lower floor below the operation floor. 5. The reactor building according to claim 4, wherein a space for installing an XY crane in the MSIV / SRV wrapping chamber is secured by removing an indoor partition wall.

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