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JP-7855133-B1 - Method and apparatus for dismantling a bottomed cylindrical member

JP7855133B1JP 7855133 B1JP7855133 B1JP 7855133B1JP-7855133-B1

Abstract

[Challenge] To efficiently dismantle bottomed cylindrical members while minimizing the effects of radioactivity. [Solution] A method for dismantling a bottomed cylindrical member is provided inside a reactor containment vessel and has a body portion extending in the vertical direction and a lower closing portion that closes the lower end of the body portion, and includes the steps of: filling a bottomed cylindrical member installed in a concrete hole with water; cutting the bottomed cylindrical member from the inside of the bottomed cylindrical member above the water level in the bottomed cylindrical member; and transporting the cut pieces generated by cutting the bottomed cylindrical member to the outside of the bottomed cylindrical member. [Selection Diagram] Figure 6

Inventors

  • 冨満 亮兵
  • 神木 良継
  • 光畑 幸史
  • 永田 亮
  • 岡村 祥典
  • 鬼塚 博徳
  • ▲濱▼本 智元

Assignees

  • 三菱重工業株式会社

Dates

Publication Date
20260507
Application Date
20251223

Claims (6)

  1. A method for dismantling a bottomed cylindrical member, which is installed in a pool inside the reactor building of a pressurized water reactor , and is placed in a concrete hole formed by recessing downward from the floor surface of a cavity formed in the pool inside the reactor building , and has a body portion that extends vertically and a lower closing portion that closes the lower end of the body portion, With the bottomed cylindrical member installed in the concrete hole, the process involves filling the bottomed cylindrical member with water, The process involves cutting the bottomed cylindrical member from the inside of the bottomed cylindrical member above the water surface in the bottomed cylindrical member, A step of transporting the cut pieces generated by cutting the bottomed cylindrical member to the outside of the bottomed cylindrical member, A method for dismantling a bottomed cylindrical member, including the member in question.
  2. The process further includes the step of draining the water from the bottomed cylindrical member and lowering the water level, The method for dismantling a bottomed cylindrical member according to claim 1, wherein the steps of cutting the bottomed cylindrical member and transporting the cut pieces to the outside of the bottomed cylindrical member are repeated in the portion above the water surface at a lowered level.
  3. The method for dismantling a bottomed cylindrical member according to claim 1 or 2, wherein in the step of cutting the bottomed cylindrical member, the bottomed cylindrical member is cut vertically at a plurality of cutting positions spaced apart in the circumferential direction of the bottomed cylindrical member, and the bottomed cylindrical member is cut circumferentially between adjacent cutting positions in the circumferential direction.
  4. A dismantling device used in the method for dismantling a bottomed cylindrical member as described in claim 1, A first disc saw having a disc-shaped first cutting disc that is located in a vertical plane extending radially around the axis of the bottomed cylindrical member and capable of cutting the bottomed cylindrical member, A second disc saw having a disc-shaped second cutting disc located in a horizontal plane intersecting the vertical direction, capable of cutting the bottomed cylindrical member, A table that supports the first disc saw and the second disc saw so that they can move in the circumferential direction about the axis of the bottomed cylindrical member, A demolition device equipped with the following features.
  5. The dismantling device according to claim 4, further comprising a gripping member capable of clamping the upper end of the bottomed cylindrical member from both radial sides centered on the axis.
  6. The bottomed cylindrical member further comprises a support member that is supported on the inner circumferential surface and is positionable relative to the inner circumferential surface, The demolition device according to claim 4 or 5, wherein the support member comprises a base member extending radially outward from the axis of the bottomed cylindrical member, and a plurality of actuators provided at intervals in the circumferential direction from the axis of the bottomed cylindrical member, and actuators that are extendable and retractable radially from the base member.

Description

This disclosure relates to a method and apparatus for dismantling a bottomed cylindrical member. Patent Document 1 discloses a method for dismantling a nuclear power plant, which involves dismantling the in-reactor structures within the reactor vessel in water stored in a work pool, and then removing the dismantled in-reactor structures from the work pool. Japanese Patent Publication No. 2017-67728 This is a longitudinal cross-sectional view showing a pressurized water reactor, which is a reactor to be dismantled according to the embodiment of this disclosure.This is a schematic diagram showing a pressurized water reactor, with water stored inside according to the embodiment, with the reactor vessel lid removed, positioned inside the reactor building.This figure shows the reactor vessel body that is to be cut by the reactor vessel dismantling method according to the embodiment.This figure shows a dismantling device used for dismantling the reactor vessel body, arranged inside a bottomed cylindrical member, in a method for dismantling a bottomed cylindrical member according to an embodiment.This is a flowchart showing a method for dismantling the reactor vessel body according to the embodiment of this disclosure.This figure shows the state in which the bottomed cylindrical member is being cut vertically during the step of cutting the bottomed cylindrical member in the dismantling method for the bottomed cylindrical member according to the embodiment.This is a plan view showing the state in which the bottomed cylindrical member is being cut vertically in the step of cutting the bottomed cylindrical member in the dismantling method for the bottomed cylindrical member according to the embodiment.This figure shows the step of cutting a bottomed cylindrical member in the circumferential direction in a method for dismantling a bottomed cylindrical member according to an embodiment.This is a plan view showing the state in which the bottomed cylindrical member is being cut in the circumferential direction during the step of cutting the bottomed cylindrical member in the dismantling method for the bottomed cylindrical member according to the embodiment.This is a plan view showing one of the steps for cutting a bottomed cylindrical member in the circumferential direction in the dismantling method for a bottomed cylindrical member according to the embodiment.This figure shows the state following Figure 10.This figure shows the step of lowering the water level in the dismantling method for a bottomed cylindrical member according to the embodiment. The following describes embodiments for implementing the dismantling method and dismantling apparatus for a bottomed cylindrical member according to this disclosure, with reference to the attached drawings. However, this disclosure is not limited to these embodiments. <Implementation> (nuclear reactor) Figure 1 is a longitudinal cross-sectional view showing a pressurized water reactor 1, which is the reactor to be dismantled according to this embodiment. The reactor illustrated in this embodiment is a pressurized water reactor 1 (PWR) that uses light water as a reactor coolant and neutron moderator, creating high-temperature, high-pressure water that does not boil throughout the entire core, sending this high-temperature, high-pressure water to a steam generator to generate steam through heat exchange, and sending this steam to a turbine generator to generate electricity. As shown in Figure 2, the pressurized water reactor 1 is located within a reactor building pool 100, which is situated inside the reactor building (not shown). The reactor building pool 100 contains a space capable of storing cooling water (water). In this embodiment, the reactor building pool 100 comprises a first cavity 110 where the pressurized water reactor 1 is located, and a second cavity 120 adjacent to the first cavity 110. The first cavity 110 has a first floor surface 111 where workers can walk. The second cavity 120 has a second floor surface 121 that is recessed from the first floor surface 111. That is, the second floor surface 121 is located vertically (up and down) Dv below the first floor surface 111. As a result, the second cavity 120 is formed as a space recessed vertically Dv below the first cavity 110. The pressurized water reactor 1 of this embodiment comprises a reactor vessel 2, an upper core structure 5, and a lower core structure 6 within a reactor containment vessel (not shown), as shown in Figures 1 and 2. The reactor vessel 2 has a reactor vessel body (bottomed cylindrical member) 21 and a reactor vessel lid 22 (upper mirror) so that internal reactor structures can be inserted inside. As shown in Figure 2, the reactor vessel 2 is positioned inside a concrete hole 15 formed to be recessed from the first floor surface 111. The reactor vessel 2 is positioned so that a portion of it (specifically, the reactor vessel lid 22) protrudes from the first floor surface 111. The reactor vessel