JP2005241527A - Method of dismantling nuclear reactor facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nuclear reactor facility dismantling method capable of dismantling efficiently a nuclear reactor, and suitable for controlling a radioactive waste of a dismantled matter collectively in one site. <P>SOLUTION: A suppression chamber is reinforced, an inner structure thereof is removed, a pressure vessel and its accessory, and a reactor containment and its accessory are dismantled to store dismantled matters thereof in the suppression chamber. A surface layer of a storage chamber inner wall face in a nuclear reactor building is removed to store removed matters thereof in the suppression chamber. The suppression chamber is sealed and covered with a concrete structure to be shielded, and a residual portion (contaminated portion) in the nuclear reactor building is dismantled thereafter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a nuclear reactor dismantling method suitable for dismantling a nuclear reactor and managing the radioactive waste in one place.

  As a method of dismantling the nuclear reactor, a laser beam is guided from a laser oscillator provided outside the nuclear reactor into the nuclear reactor via an optical fiber, and a cutting gas is blown while irradiating this laser beam to the cutting part of the nuclear reactor equipment. Therefore, it has been proposed to cut the reactor equipment (see, for example, Patent Document 1). It has also been proposed to dismantle the reactor by remotely operating a manipulator installed in the reactor (see, for example, Patent Document 2).

There is also a method for dismantling the nuclear reactor that builds a scaffold along the biological shielding wall of the nuclear reactor and installs an elevator inside the biological shielding wall to streamline the dismantling work of the biological shielding wall and the work of carrying out the dismantling to the outside. Has been proposed (see, for example, Patent Documents 3 and 4).
JP 2001-166090 A JP-A-8-75892 JP 2000-9894 A JP-A-5-273390

  However, in the above-mentioned Patent Documents 1, 2, 3, 4 and various seminars, only individual technical methods for dismantling the nuclear reactor are proposed. Moreover, there is no mention of how to dispose of the dismantled materials, especially how to store radioactive contaminants. Therefore, in general, dismantled materials are divided into radioactive contaminants and contaminated materials, and the contaminated materials are disposed of as industrial waste, and the radioactive contaminants are collected and stored in a specific radiation control facility. It's only possible.

  The present invention has been made in view of such circumstances, and its purpose is to efficiently dismantle a nuclear reactor and to manage atomic waste suitable for managing the dismantled radioactive waste in one place. The purpose is to provide a method for dismantling furnace equipment.

  In the present invention, a suppression chamber provided in an annular shape around a reactor containment vessel surrounding a reactor pressure vessel has a large pipe cross section with an inner diameter of about 4 m, for example, and draws a circle with a diameter of 30 to 40 m. It is made by paying attention to the fact that it has a large space that is large enough to store the dismantled matter (radioactive contaminants) dismantled from the reactor equipment.

Therefore, in order to achieve the above-described object, the reactor facility dismantling method according to claim 1 of the present invention is:
<a> Reinforcing the lower layer of the suppression chamber provided in an annular shape around the reactor containment vessel and removing the internal structure of the suppression chamber [preparation process]
<b> Thereafter, the pressure vessel and its accessory, and the reactor containment vessel and its accessory are dismantled and the dismantled product is stored in the suppression chamber, and the reactor containment vessel in the reactor building The surface layer of the storage room wall surface is deleted and the deleted material is stored in the suppression chamber [dismantling process],
<c> Next, the suppression chamber is sealed, and the suppression chamber is covered with a concrete structure and shielded [sealed storage treatment].
<d> The remaining part (contaminated part) of the reactor building is disassembled.

  In other words, the reactor facility dismantling method according to the present invention removes the internal structure of the suppression chamber, thereby forming a large space for accommodating the reactor dismantling material inside the suppression chamber. The pressure vessel and its associated material dismantled (radioactive contaminants), the reactor containment and its associated dismantled materials (radioactive contaminants), and the inner wall surface layer of the reactor containment vessel storage chamber were deleted. After sequentially storing the deleted items (radioactive contaminants), sealing the suppression chamber, covering it with a radioactive shield (concrete), storing it, and dismantling the remaining reactor building (contaminated site) It is characterized by treating waste as industrial waste.

Preferably, as described in claim 2, with respect to the operation of storing the dismantled matter (radioactive contaminants) resulting from the dismantling of the pressure vessel or the like into the suppression chamber, a manhole provided in the suppression chamber, and / or Alternatively, it may be performed through a vent pipe connecting the suppression chamber and the reactor containment vessel.
More preferably, as described in claim 3, a rail is laid in the suppression chamber from which the internal structure has been removed, and a cask (storage container) is movably provided on the rail. Alternatively, it is desirable that the cask is sealed and stored in the suppression chamber after storing the deletion (radioactive contaminant). More specifically, the cask is sealed as described in claim 4, for example, after concrete is filled in a cask containing dismantled materials and / or deleted materials, the opening is sealed with a steel plate lid. It can be done by welding.

  As for the cask, as described in claim 5, a semi-cylindrical container body having wheels that run on the rail, that is, a round boat type container in which the cylindrical container is halved along its axial direction. The dismantled material and / or the deleted material is stored in this cask and sealed as described above, and then turned upside down and overlapped on another cask on the rail to form a cylinder. It is desirable to store it in the chamber.

  As for the reinforcement of the lower layer portion of the suppression chamber, it is preferable to actively utilize, for example, a dismantling material (contaminated material) of a clean facility in the reactor building as described in claim 6.

  According to the reactor facility dismantling method according to the present invention, the suppression chamber of the reactor facility is effectively utilized as it is as a storage area for the dismantled material, and a pressure vessel, a reactor containment vessel, etc. are provided in the internal space of the suppression chamber. After storing this demolition (radioactive contamination), sealing this suppression chamber, and covering it with a radioactivity shield (concrete), the demolition (radioactive contamination) is simply stored together, It is not necessary to transfer the demolition (radioactive contamination) to the outside of the nuclear reactor equipment by using a transportation means such as a truck, so that the diffusion range of the contamination can be minimized. Moreover, since radioactive contaminants (disassembled materials) dismantled from the pressure vessel and the like are simply carried and stored in the suppression chamber sequentially through the manhole and vent pipe of the suppression chamber, the dismantling procedure can be simplified. And the efficiency of the dismantling work can be improved. Then, the site where the reactor facility was dismantled can be used as it is as a storage place for the dismantled material, and the spread of the radioactive contamination range can be prevented.

  In particular, after the casks containing the dismantled materials and / or deleted materials (radioactive contaminants) are individually sealed, the caskes are finally sealed while the sealed casks are sequentially gathered in one place. Objects and deletions (radioactive contaminants) can be sealed multiple times to reliably prevent the spread of radioactivity. At this time, by using a semi-cylindrical cask and stacking the cask inverted upside down on another cask, the two caskes are stored in a stacked state, so that the circular pipe cross section A large number of casks can be stored by effectively using the internal space of the suppression chamber.

  Furthermore, if the dismantling material (contaminated material) of the clean equipment in the reactor building is actively used for reinforcing and fixing the suppression chamber described above, the amount of industrial waste generated by dismantling can be reduced. The effect that the equipment cost required for the dismantling work can be kept low is exhibited.

Hereinafter, a method for dismantling a nuclear reactor facility according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1A is a longitudinal sectional view showing a schematic configuration of a nuclear reactor facility to be dismantled, and FIG. 1B is a plan view of a suppression chamber (pressure suppression chamber) forming a part of the nuclear reactor facility. . The reactor facilities to be dismantled are those that have been previously exposed to the radiation in the fuel and reactor vessel, and the remaining part (equipment) has been decontaminated (washing out the radioactivity). Consists of. In addition, clean facilities that can be disposed of as general industrial waste among the various facilities in the reactor facilities have been removed in advance, and the remaining reactor facilities (pressure vessel, reactor containment vessel, reactor building, etc.) ) Is subject to dismantling.

  The reactor equipment shown in FIGS. 1 (a) and 1 (b) will be briefly described. This reactor equipment is a reactor pressure vessel (RPV) 1 and a steel product provided around the reactor pressure vessel 1. The reactor containment vessel (PCV) 2 is provided, and the reactor containment vessel 2 is provided in a concrete reactor building (R / B) 3 as a radioactive shield. In particular, the periphery of the reactor containment vessel 2 is thickly covered with a biological shielding wall 3a that forms a part of the reactor building (R / B) 3, and the biological shielding wall 3a allows the radioactive contamination region and the clean region to be separated. Is isolated.

  Further, the lower part of the floor of the reactor building (R / B) 3 is located around the lower part of the reactor containment vessel 2. A suppression chamber chamber 5 in which a suppression chamber (S / C) 4 is disposed is provided in an annular shape. The suppression chamber 4 is, for example, a steel pipe having an inner diameter of about 4 m and arranged in an annular shape with a pipe having a diameter of 30 to 40 m around the reactor containment vessel 2 as shown in a plan view in FIG. Made up of. The suppression chamber 4 is connected to the dry well of the reactor containment vessel 2 through a plurality of (for example, eight) vent pipes 6.

  In FIG. 1, reference numeral 7 denotes a PCV connection facility (instrument) in which a reactor containment vessel (PCV) 2 and a clean region of the reactor building 3 are connected via a biological shielding wall 3 a forming a part of the reactor building 3. 8, 8 are pipes arranged in the reactor containment vessel 2, and 9 is ancillary equipment such as pipes arranged in the suppression chamber chamber 5. Further, the suppression chamber 5 is usually formed as an underground structure in the reactor building 3.

  FIG. 2 is a diagram showing a schematic procedure of the dismantling method according to the present invention in dismantling the reactor equipment having the above-described structure, and FIGS. 3 to 16 respectively show the outline of the work contents in each work stage. ing. Referring to these drawings, the reactor facility demolition method according to one embodiment of the present invention will be described. Prior to dismantling the reactor facility, the fuel and various facilities in the reactor containment vessel 2 are carried out. In addition, the inside of the containment vessel 2 is decontaminated (radioactive removal). Moreover, what can be processed as general industrial waste such as a control table in the reactor building 3 is carried out and disposed of in advance.

  Thereafter, as a first stage, first, the suppression chamber 4 is reinforced by using the dismantling material of the clean equipment in the reactor building 3 as shown in FIG. 3, and between the lower portion of the suppression chamber 4 and the bottom surface of the suppression chamber chamber 5. Concrete is poured into the plate to fix the suppression chamber 4 [Step S1]. Specifically, as shown in FIG. 3, a reinforcing material (dismantling material) 11 is provided between the outer peripheral surface of the suppression chamber 4 and the bottom surface / wall surface of the suppression chamber 5, and a so-called dencil tape is provided on the outer surface of the suppression chamber 4. After the anti-corrosion / rust-proofing treatment, such as by winding the concrete, the concrete 12 is poured into the lower layer of the suppression chamber chamber 5 to reinforce and fix the suppression chamber 4.

  Next, as shown in FIG. 4, in the clean region in the reactor building 3, the PCV connection equipment (instruments, piping, etc.) 7 is cut, and the cut portion is sealed with a cap 13, so that the reactor pressure vessel ( Instruments and piping connected to the RPV 1 are removed, and the reactor pressure vessel (RPV) 1 is isolated from the clean area in the reactor building 3 [step S2]. Further, a structure such as a vent pipe and a downcomer provided in the suppression chamber 4 is removed [Step S3]. By removing the structure in the suppression chamber 4, a storage space for a dismantled reactor facility, etc., which will be described later, is secured.

  Thereafter, as shown in FIG. 5, the rail 14 is laid on the bottom surface of the suppression chamber 4 from which the internal structure has been removed, and the monorail 15 is laid on the ceiling surface [step S4]. Incidentally, the rail 14 forms a traveling path of a cask 16 for storing dismantled objects as shown in FIG. 6, and the monorail 15 forms a traveling path of a crane (not shown). The cask 16 is, for example, a semi-cylindrical steel container body provided with wheels 16a running on the rails 14, that is, a round wooden boat type having a width of 3 m and a length obtained by halving the cylindrical container along its axial direction. It consists of a container of about 3m. Loading of the dismantled material into the cask 16 is performed using a crane attached to the monorail 15 described above. The cask 16 and the crane are incorporated into the suppression chamber 4 through the manhole 4a provided in the suppression chamber 4 and the vent pipe 6 described above. In addition, the cask 16 is incorporated into the suppression chamber 4 in a necessary number sequentially as the dismantling process described later proceeds.

  When the preparatory process for the reactor dismantling operation is completed by the above-described operations, the structures in the reactor building (R / B) 3 and the reactor containment vessel (PCV) 2 as shown in FIG. The dismantling work is started [step S5]. Then, the dismantled product is carried into the suppression chamber 4 via the manhole 4a and the vent pipe 6 as shown in FIG. 7, and sequentially loaded onto the cask 16 to seal the cask 16 [step S6]. The casks 16 are packed with the dismantled material and sealed. After the required amount (bulk) of dismantled material is packed into the cask 16, the concrete or mortar is poured into the cask 16 to fix the dismantled material, and the dismantled material is fixed. The plate is covered with a plate-like lid 16b made of a steel plate and covered with the opening (the upper surface of the cask 16).

  When the dismantled material is loaded and sealed on the plurality of casks 16, some of the casks 16 are turned upside down as shown in FIG. 8 and overlapped on the remaining casks 16. In other words, one of the cask 16 having a semicircular cross section is turned upside down and overlapped on another cask 16 to join the two casks into a cylindrical shape. By such overlapping of the cask 16, the cask 16 can be stored effectively using the space having a circular cross section of the suppression chamber 4. Then, the two casks 16 overlapped one by one are moved along the rails 14 and are sequentially gathered at predetermined locations in the suppression chamber 4 as shown in FIG.

  If the structures in the reactor building (R / B) 3 and the reactor containment vessel (PCV) 2 are disassembled as described above, packed in the cask 16 and stored in the suppression chamber 4, then FIG. As shown in FIG. 11, the reactor pressure vessel (RPV) 1 and its ancillary equipment are disassembled, and as shown in FIG. 11, the reactor containment vessel (PCV) 2 and its ancillary equipment are disassembled [step S7]. These disassembled materials are similarly transferred into the suppression chamber 4 and packed into the cask 16, and the cask 16 is sealed and stored in the suppression chamber 4 [step S8].

  Next, as shown in FIG. 12, the surface layers such as the inner wall surface and the bottom surface of the concrete biological shielding wall 3a surrounding the aforementioned reactor containment vessel (PCV) 2 of the reactor building (R / B) 3, for example, It is deleted over a thickness of 50 to 70 mm [Step S9], and the deleted material is similarly packed in the cask 16 and stored in the suppression chamber 4 [Step S10]. That is, since there is a high possibility that the surface layer such as the biological shielding wall 3a is contaminated by radioactivity, the surface layer is scraped off and sealed using the cask 16 in the same manner as the dismantled material described above. Then, all of the plurality of casks 16 each sealing these dismantled items and deleted items are accommodated in a suppression chamber 4 forming a pipe line having a diameter of 30 to 40 m.

  After all of the radioactive contaminants are stored in the cask 16 and stored in the suppression chamber 4 as described above, the concrete 17 is poured into the suppression chamber 4 to fix each cask 16 as shown in FIG. Then, the casted concrete 17 further shields the cask 16 and eventually the dismantled material packed in the cask 16. Then, the vent pipe 6 connecting the suppression chamber 4 and the reactor containment vessel (PCV) 2 is sealed with a metal cap 18 [step S11]. Then, concrete is poured into the suppression chamber 5 and the entire suppression chamber 4 is covered and hardened, and then a concrete isolation wall 19 having a predetermined thickness is formed to cover the entire suppression chamber 5 as shown in FIG. .

  Thereafter, the entire reactor building (R / B) 3 remaining after removing all radioactive contaminants is dismantled as shown in FIG. 15, and the dismantled material does not contain any radioactive contaminants. Therefore, it is disposed of as general industrial waste [Step S12]. Then, on the former site where the reactor building (R / B) 3 was dismantled, for example, as shown in FIG. The radioactive leak from the radioactive waste (dismantled etc.) embedded in is monitored [step S13]. In this monitoring, for example, a radiation monitor (sensor) 21 or the like is installed in the vicinity of the suppression chamber chamber 5 covered with concrete, and the water quality such as rain water or ground water is inspected to radiate from the cask 16 described above. This is done by monitoring for leaks.

  Thus, according to the dismantling method in which the reactor facility is disassembled as described above, and the dismantled matter contaminated by the radioactivity is stored and stored using the suppression chamber 4 that the reactor facility has, The demolished material can be effectively shielded and stored in the ground without being transported using a truck or the like. In addition, it is possible to store the decontaminated matter by moving it into the suppression chamber 4 within the reactor facility to be dismantled. Accordingly, it is possible to effectively prevent the diffusion of the contamination accompanying the transfer of the dismantled material, and to minimize the contamination range.

  Further, according to the above-described embodiment, since the dismantled matter contaminated by the radioactivity is sequentially sealed using the cask 16, the diffusion of the contamination can be effectively prevented also in this respect. Further, a semi-cylindrical cask 16 is used, and this cask 16 is turned upside down and overlapped on another cask 16 to form a columnar shape and stored in the suppression chamber 4. There is also an advantage that a lot of demolitions can be stored and stored by effectively utilizing the space.

  The present invention is not limited to the embodiment described above. Here, an example in which the dismantled product is sealed using the cask 16 has been described, but the dismantled material such as the pressure vessel 1 is fixed and stored while covering a predetermined amount of concrete in order from a predetermined region of the suppression chamber 4. Anyway. Even when the cask 16 is used, its size, shape, etc. are sufficient if it can be accommodated in the suppression chamber 4. In addition, it is possible to use other fillers instead of concrete or mortar to fix the dismantled material in the cask 16, and mortar or other fillers to fix the cask 16 in the suppression chamber 4. It is also possible to use. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

The figure which shows schematic structure of the nuclear reactor equipment used as the object of demolition. The figure which shows an example of the schematic process sequence of the dismantling method of the nuclear reactor equipment which concerns on one Embodiment of this invention. The figure which shows the mode of reinforcement and fixation of the suppression chamber 4. FIG. The figure which shows the mode of the removal of the structure in the suppression chamber 4, and the cutting and sealing of PCV connection equipment (instruments, piping, etc.) 7. The figure which shows the mode of laying of the rail 14 grade | etc., In the suppression chamber 4. FIG. The figure which shows the example of a cask. The figure which shows the mode of loading to the cask 16 of the structure in the reactor building (R / B) 3 and the reactor containment vessel (PCV) 2, and its demolition thing. The figure which shows the form of the stacking of the cask 16 which accommodated the demolition thing. The figure which shows the form of the storage in the suppression chamber 4 of the cask 16 which accommodated the demolition thing. The figure which shows the mode of the dismantling of the reactor pressure vessel (RPV) 1 and its incidental equipment. The figure which shows the mode of dismantling of the reactor containment vessel (PCV) 2 and its incidental equipment. The figure which shows the mode of deletion of the surface layer of the biological shielding wall 3a in the reactor building (R / B) 3. FIG. The figure which shows the mode of sealing and fixing of the cask 16 in the suppression chamber 4. FIG. The figure which shows the mode of the sealing of the suppression chamber 4 in the suppression chamber chamber 5, and fixation. The figure which shows the mode of the demolition of the reactor building (R / B) 3. The figure which shows the mode of the storage of the demolition thing accommodated in the suppression chamber 4 using the cask 16. FIG.

Explanation of symbols

1 Reactor pressure vessel (RPV)
2 Reactor containment vessel (PCV)
3 Reactor building (R / B)
4 Suppression chamber (S / C)
5 Suppression chamber 6 Vent pipe 7 PCV connection equipment (instruments, piping, etc.)
DESCRIPTION OF SYMBOLS 11 Reinforcement material 14 Rail 15 Monorail 16 Cask 19 Concrete isolation wall 20 Monitoring building 21 Radioactivity monitor (sensor)

Claims (6)

Reinforcing the lower portion of the suppression chamber provided in an annular shape around the reactor containment vessel surrounding the reactor pressure vessel, and removing the internal structure of the suppression chamber;
Thereafter, the pressure vessel and its accessory, and the reactor containment vessel and its accessory are disassembled and the dismantled product is stored in the suppression chamber, and the inner wall surface of the reactor containment vessel in the reactor building Delete the surface layer and store the deletion in the suppression chamber,
Next, the reactor chamber is dismantled after sealing the suppression chamber and covering the suppression chamber with a concrete structure to shield it, and then dismantling the reactor building.   Storage of the dismantled material and the deleted material in the suppression chamber is performed through a manhole provided in the suppression chamber and / or a vent pipe connecting the suppression chamber and the reactor containment vessel. The dismantling method of the nuclear reactor equipment according to claim 1.   The dismantled material and the deleted material are stored in the suppression chamber after a rail is laid in the suppression chamber from which the internal structure is removed, and then the dismantled material and / or the deleted material is stored in a cask provided on the rail. The reactor equipment dismantling method according to claim 1, further comprising: sealing the cask.   The sealing of the cask containing the dismantled material and / or the deleted material is performed by filling the cask with concrete or mortar and sealingly welding the opening with a steel plate lid. Item 4. Reactor facility dismantling method according to Item 3.   The cask is formed of a semi-cylindrical container having wheels that run on the rail. The cask is housed and sealed with the dismantled material and / or the deleted material, and then the upper and lower sides thereof are turned upside down. The reactor equipment dismantling method according to claim 3, wherein the reactor equipment is stored in the suppression chamber in a cylindrical state by being superimposed on a cask.   The method for dismantling a nuclear reactor according to claim 1, wherein the reinforcement of the lower layer portion of the suppression chamber is performed using a dismantling material for a clean facility in the nuclear reactor building.

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