JP2009085867A - Handrail device in nuclear power plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a handrail device in a nuclear power plant that certainly prevents occurrence of the accident that a foreign substance with a risk of breakage of a fuel assembly disperses and mixes in a used fuel pool, and facilitates installation in and removal from the periphery of the used fuel pool. <P>SOLUTION: This handrail device in the nuclear power plant is a handrail installed around the used fuel pool in the nuclear power plant. The handrail comprises handrail frames having a shielding plate inside them, an overlap type link section for blocking the clearance between adjacently arranged handrail frames, and a banner-like sheet for preventing mixing of a foreign substance attached to the lower side of the handrail frames via a hanger rail. The handrail is of retractable type, removal type, or fixed type. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a handrail device in a nuclear power plant, for example, installed around a spent fuel pool in a nuclear power plant.

  Conventionally, as shown in FIG. 10, a spent fuel pool P in a nuclear power plant, a nuclear reactor connected to a storage pool such as a steam separator, and other pipes that have been subjected to a general bending process. A handrail L having a structure is installed.

  This handrail L is installed only in consideration of human safety. For example, a bolt, a nut, a washer, It does not prevent foreign matters such as metal pieces, paint film pieces, sheets and tapes from entering.

  In recent nuclear power plants, fuel damage due to such foreign matter (especially metals) mixing, that is, debris damage frequently occurs. Therefore, a storage pool such as a spent fuel pool P and a steam separator is provided. Measures are taken to prevent foreign matter from being mixed, for example, by curing the handrail L itself installed around the connected nuclear reactors with a sheet or tape.

For example, as shown in FIG. 11, this debris breakage is caused by a fluid in a state where so-called debris, which is a metal piece foreign matter, is mixed in the fuel assembly R and captured by the spacer portion S or the like. It is the so-called fretting that the pipe surface wears.
nothing special

  However, in the past, although each handrail itself was cured with, for example, a sheet or tape, there was a gap between the handrails, so the spent fuel pool side, the reactor side and the floor side Cannot be completely isolated from each other, and there is a possibility that foreign matters such as metal pieces scattered from the floor side may be mixed through the gap.

  In addition, due to the inadequate curing method of handrails and deterioration due to long-term use of handrails, as a secondary disaster, sheet pieces and tape pieces are used as a spent fuel pool, air / water separator storage pool, etc. There was a frequent problem that it was mixed into the reactors connected to the reactor.

  Therefore, the present invention has been created in view of the existing circumstances as described above. For example, foreign substances that may cause damage to the fuel assembly are scattered and mixed in the spent fuel pool. An object of the present invention is to provide a handrail device in a nuclear power plant that can reliably prevent the occurrence of a situation and can be easily installed and removed around a spent fuel pool.

  A handrail device in a nuclear power plant according to the present invention is a handrail installed around a spent fuel pool in a nuclear power plant, and the handrail is disposed adjacent to a handrail frame provided with a shielding plate on the inside. The above-mentioned problem is provided by including an overlapping type connecting portion for closing a gap between the handrail frames, and a banner-like foreign matter mixing prevention sheet attached to the lower side of the handrail frame via a hanger rail. Settled.

  Further, the handrail is one of a retractable type, a removable type, and a fixed type, thereby solving the above-described problem.

  Furthermore, the retractable handrail has a bracket movable part installed at the periphery of the spent fuel pool so that the handrail frame can be folded and supported in one end direction. .

  Further, the bracket movable portion is formed by drilling a pair of upper and lower long holes that are inclined forward and an arc-shaped guide hole that extends from the upper end of the long hole located on the upper side toward the front lower side. A pair of left and right plates, an upper butterfly bolt that inserts and fixes the lower end of the leg of the handrail frame between both plates, and a lower end of the leg of the handrail frame that penetrates through a long hole located below the two plates The lower part for fixation which is inserted in the long hole which has a guide hole located in the upper part of both board materials, and supports the bolt so that it can rotate, and is united with the leg part lower end of a handrail frame A side wing nut is provided, the lower wing nut is loosened, and then the handrail frame is pulled up to slide the lower wing nut and the support bolt diagonally upward along each elongated hole, and then the support bolt is centered. Slide the lower wing nut along the arc-shaped guide hole as By tilting the reluctant handrail frame and solve the problems also discussed above.

  In addition, a tiltable pole standing on the base and the bracket movable so that the spent fuel pool with the handrail frame removed can be used as a substitute for the handrail frame by dividing it with a safety rope The above-mentioned problem has been solved by providing a fixed pole erected through the section, a retractable pole, and a safety rope inserted into the ring at the upper end of the fixed pole.

  At the top of the handrail frame, a hook for hanging the jig and a hook for hanging the float are attached, and the shielding plate inside the handrail frame has precautions for easy-to-see surroundings and radiation signs. The above-mentioned problem was solved by the fact that a mounting seat for receiving a signboard or the like is attached.

  According to the present invention, it is possible to reliably prevent the occurrence of a situation in which foreign matter having a risk of causing damage to the fuel assembly is scattered and mixed in the spent fuel pool. In addition, handrails can be easily installed and removed around the spent fuel pool.

  Specifically, it is a handrail installed around a spent fuel pool in a nuclear power plant, and the handrail has a gap between a handrail frame provided with a shielding plate inside and a handrail frame arranged adjacent to each other. There is a risk of causing damage to the fuel assembly because it is equipped with a stacking type connecting part for closing and a curtain-like foreign matter mixing prevention sheet attached to the underside of the handrail frame via a hanger rail It is possible to reliably prevent the occurrence of a situation where foreign matters are scattered and mixed in the spent fuel pool.

  In addition, since the handrails are either retractable, removable, or fixed, handrails that can realize a favorable situation around the spent fuel pool at the nuclear power plant are appropriately selected and installed. can do.

  Furthermore, the retractable handrail has a bracket movable part installed at the periphery of the spent fuel pool so that the handrail frame can be folded and supported in one end direction. Work can be done easily.

  Furthermore, the bracket movable portion is formed by drilling a pair of upper and lower long holes in the forward inclined direction and an arcuate guide hole extending from the upper end of the long hole located on the upper side toward the front lower side. A pair of left and right plates, an upper butterfly bolt that inserts and fixes the lower ends of the leg portions of the handrail frame between the two plate materials, and a lower hole of the leg portions of the handrail frame that are penetrated through a long hole located below the both plates. The lower part for fixing which is inserted in the long hole which has the guide hole located in the upper side of both board materials, and the support bolt which supports so that it can rotate, and is united with the leg part lower end of a handrail frame Side wing nut, loosen the lower wing nut, and then pull up the handrail frame to slide the lower wing nut and the support bolt diagonally upward along each slot, and then attach the support bolt. Slide the lower wing nut along the arc-shaped guide hole as the center Since tilting the handrail frame while, safe, yet the retractable handrail that can be folded with one touch, can be inexpensively manufactured with a simple configuration.

  In addition, a tiltable pole standing on the base part and the bracket movable part so that the spent fuel pool with the handrail frame removed can be used as a substitute for the handrail frame by dividing it with a safety rope A safety pole for safety measures after the completion of the movement of the fuel changer. Rope can be easily installed around the spent fuel pool, and disassembly and removal of these can be easily performed.

  In addition, a hook for hanging a jig and a hook for hanging a floating ring are attached to the upper side of the handrail frame, and the shielding plate inside the handrail frame has precautions and radiation for surrounding areas that are easily visible. Since a mounting seat for receiving a signboard such as a sign is attached, it is possible to call attention in work in the spent fuel pool such as movement of a fuel changer.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the handrail device in the nuclear power plant according to the present invention is installed around the spent fuel pool P, and each of the retractable handrail 1a, the removable handrail 1b, and the fixed handrail 1c. It is comprised by three bodies.

  For example, on one end side of the spent fuel pool P where the low-floor type fuel changer is installed, which is connected to the reactor, there is a retractable handrail 1a and a detachable handrail for work such as moving the fuel changer. The type handrail 1b is adopted. In addition, a stationary handrail 1c is installed around the other spent fuel pool P. The reactor communicates with a storage pool such as a steam separator.

  The bottom of this low-floor type fuel changer is approximately at the same level as the fuel change floor, and it is necessary to remove the handrail L with a height of about 1 m each time. In this way, the structure is such that the handrail L can be tilted down, so that it is possible to shorten each work time such as fuel replacement work and reduce the burden on the operator.

  That is, as a specific configuration of the retractable handrail 1a, as shown in FIGS. 2 (b) and 3 (a), a shielding plate 2a made of metal or the like is provided inside the handrail frame 2 having a substantially rectangular shape. Provided. Since this shielding plate 2a has been baked, it is excellent in decontamination, does not require any curing, and does not contain deteriorated sheet pieces or tape pieces.

  Further, as shown in FIGS. 2A and 2B, a connecting portion 5 is provided between the handrail frames 2 by overlapping the plates in order to eliminate this gap.

  Further, as shown in FIG. 3B, a hanger rail 21 is provided on the lower frame side of the handrail frame 2 and is transparent in consideration of workability such as wire lashing accompanying temporary placement of a high-dose article. A hanging curtain-shaped foreign matter mixing prevention sheet 22 made of a urethane material close to is attached to the hanger rail 21 so as to be in contact with the floor surface.

  The hanger rail 21 is provided with a slit portion 23 along the longitudinal direction on the lower surface of a horizontally long rectangular tube material, and both sides are opened. Then, from one opening side, the rod 24 of the foreign matter mixing prevention sheet 22 having one end wound around the rod member 24 is inserted, and attached so that the lower side of the foreign matter mixing prevention sheet 22 is pulled out from the slit portion 23. It is said.

  A round bar 25 is arranged at the opening edge of the slit portion 23 so as not to damage and break the foreign matter mixing prevention sheet 22 that is pulled out. Thereby, it is configured so that foreign matter can be prevented from entering the spent fuel pool P from the floor side.

  Further, as shown in FIGS. 8 and 9, the bracket movable part 11 in which both leg parts 3 extending downward from the left and right ends of the handrail frame 2 are installed on the periphery of the spent fuel pool P via the base part 4. The handrail frame 2 itself can be folded in one end direction.

  As shown in FIGS. 4 (a) and 4 (b), the bracket movable portion 11 is configured such that the rear ends of a pair of plate members 12 facing each other are attached to the base via bolts 14 by attachment members 13 having an inverted L shape. A pair of upper and lower elongated holes 15a and 15b are formed in each of the plate members 12, and the upper end of the elongated hole 15a located on the upper side is directed downward and forward. An arcuate guide hole 15c is extended.

  Then, a rectangular tube-like support pipe 17 is formed by inserting the lower end of the leg portion 3 of the handrail frame 2 and fixing the leg portion 3 so as to be detachable by the upper side butterfly bolt 16 for fixing the leg portion. The lower end of the support pipe 17 is supported by a support bolt 18 which is fitted between a pair of plate members 12 which are opposed to each other and penetrates through a long hole 15b located on the lower side of both plate members 12. .

  4 (a) and 4 (b), a lower wing nut 19 for fixing the bracket movable portion 11 is provided in a long hole 15a having a guide hole 15c located on the upper side of the plate member 12. The lower wing nut 19 itself can be loosened by being inserted through the front side surface of the support pipe 17.

  When tilting the handrail frame 2 with respect to the bracket movable portion 11, first, the lower wing nut 19 is loosened, and the handrail frame 2 is lifted upward by about 3 cm, whereby the lower wing nut 19 and the supporting bolt 18 are supported. Slides obliquely upward along the long holes 15a and 15b, and further tilts the handrail frame 2 forward so that the lower wing nut 19 slides along the arcuate guide hole 15c with the support bolt 18 as the center. Since it moves, it is comprised so that the handrail frame 2 can be tilted reliably and easily.

  In addition, around the spent fuel pool P in a state where the handrail frame 2 is removed can be partitioned by an alternative safety rope 31.

  That is, the handrail frame 2 is disassembled and removed from the bracket movable portion 11, and the fixed pole 33 shown in FIGS. 5D to 5E is erected via the bracket movable portion 11.

Furthermore, in places where the bracket movable part 11 does not exist, the retractable poles 32 are fixed at equal intervals along the base part 4 around the spent fuel pool P with bolts 14 shown in FIG. , I try to stand.

  The safety rope 31 is inserted into the rings 32 a and 33 a at the upper ends of the retractable pole 32 and the fixed pole 33.

  Thus, when the safety rope 31 is stretched, the hook (not shown) of the safety rope 31 is sequentially inserted through the tiltable pole 32 and the rings 32a and 33a at the upper end of the fixed pole 33, and the canal portion (not shown) Until the ring 33a at the upper end of the last fixed pole 33 is attached.

  Further, as shown in FIG. 6 (a), a hook 41a for hanging a floating ring, which is formed by bending a U-shaped frame into a U-shape, for example, is attached to the upper side of the handrail frame 2 near the fuel inspection place. Yes. Moreover, as shown in FIG.6 (b), the hook 41b for jig | tool suspension bent to a C-ring shape is attached to the upper side of the handrail frame 2. As shown in FIG.

  Further, as shown in FIGS. 7A and 7B, the shielding plate 2a inside the handrail frame 2 is provided with a slit for receiving a signboard Q such as a precaution to a place that is easily noticeable in the surrounding area or a radiation sign. A plurality of mounting seats 42 made of a frame material are provided to alert the user during work.

  Next, an example of assembly, use, and operation of the best mode of the present invention configured as described above will be described.

  First, as shown in FIG. 1, in the normal installation state, for example, the retractable handrail 1 a is attached to one end of the spent fuel pool P where the low bed type fuel changer is connected to the reactor. An outer handrail 1b is installed. Further, around the other spent fuel pool P, a fixed handrail 1c is installed.

  When using a fuel changer, first, the detachable handrail 1b is removed from a bracket (not shown), moved to a place where it does not interfere with the travel of the fuel changer, and temporarily placed.

  Next, preparation for a tilting operation of the retractable handrail 1a is performed. At this time, before the handrail frame 2 is tilted from the bracket movable portion 11, it is confirmed that the upper side butterfly bolt 16 for fixing the leg portion is securely tightened (see FIG. 4A).

  And as shown in FIG. 8, the lower wing nut 19 for fixation in the bracket movable part 11 is loosened, and the handrail frame 2 is pulled up. At this time, the lower wing nut 19 and the support bolt 18 slide and move obliquely upward along the long holes 15a and 15b (see FIG. 4A).

  Then, as shown in FIG. 9, when the handrail frame 2 is tilted forward, the lower hand wing nut 19 slides along the arcuate guide hole 15c around the support bolt 18 and the handrail frame 2 itself lies sideways. Is done.

  At this time, the foreign matter mixing prevention sheet 22 suspended on the hanger rail 21 is attracted to the near side so that the bracket movable portion 11 is not pinched. And leave it on the floor quietly to avoid impact.

  Then, the safety rope 31 is removed and the fuel changer is moved. At this time, the retractable pole 32 is laid down along the curve liner by the bracket movable portion 11.

  After completion of the movement of the fuel changer, a safety rope 31 for safety measures is installed around the spent fuel pool P.

  At this time, the hook (not shown) of the safety rope 31 is sequentially inserted into the rings 32a and 33a at the upper ends of the retractable pole 32 and the fixed pole 33, and when the canal portion (not shown) is reached, the last fixed pole 33 is reached. A hook is attached to the ring 33a at the upper end.

  The handrail device in the nuclear power plant according to the present invention is widely used as a handrail device in various fields, for example, installed around a nuclear reactor or a storage pool such as a steam separator in addition to a spent fuel pool. Can be used.

FIG. 3 is a perspective view of a state in which a retractable handrail, a removable handrail, and a fixed handrail are installed around a storage pool such as a spent fuel pool, a nuclear reactor, and a steam separator. It shows specific configurations of a retractable handrail, a removable handrail, and a fixed handrail. (A) is a plan view, (b) is a front view, and (c) is a plan view showing a connection portion between the handrails. is there. The example of attachment of a foreign material mixing prevention sheet is shown, (a) is a front view, (b) is a side view which expanded the principal part. An example of a bracket movable part is shown, (a) is a side view, (b) is a front view. An example of a retractable pole and a fixed pole is shown, (a) is a front view of the retractable pole, (b) is a side view, (c) is a plan view, and (d) is a front view of the fixed pole. The figure (e) is also a plan view. An example of hook attachment is shown, (a) is an explanatory view of a hook for hanging a floating ring, and (b) is an explanatory view of a hook for hanging a jig. An example of the mounting seat for signboard reception with respect to the shielding board inside a handrail frame is shown, (a) is a top view, (b) is a front view. It is a perspective view of the state before tilting a handrail frame via a bracket movable part. It is a perspective view of the state which tilted the handrail frame via the bracket movable part. It is a perspective view which shows the installation state of the handrail in a prior art example. It is explanatory drawing which shows an example of fretting of the fuel cladding tube in a prior art example.

Explanation of symbols

P ... spent fuel pool Q ... signboard L ... handrail R ... fuel assembly S ... spacer 1a ... retractable handrail 1b ... removable handrail 1c ... fixed handrail 2 ... handrail frame 2a ... shielding plate 3 ... leg DESCRIPTION OF SYMBOLS 4 ... Base part 5 ... Connection part 11 ... Bracket movable part 12 ... Plate material 13 ... Mounting member 14 ... Bolt 15a, 15b ... Long hole 15c ... Guide hole 16 ... Upper side butterfly bolt 17 ... Support pipe 18 ... Support bolt 19 ... Lower part Side wing nut 21 ... Hanger rail 22 ... Foreign matter prevention sheet 23 ... Slid part 24 ... Bar material 25 ... Round bar 31 ... Safety rope 32 ... Retractable pole 32a ... Ring (1)
33 ... Fixed pole 33a ... Ring (2)
41a ... Hook for hanging the jig 41b ... Hook for hanging the floating ring 42 ... Installation seat

Claims (6)

  A handrail installed around a spent fuel pool in a nuclear power plant, the handrail being overlapped to close a gap between a handrail frame provided with a shielding plate inside and a handrail frame disposed adjacent to each other A handrail device in a nuclear power plant, comprising: a connecting portion of a type and a curtain-like foreign matter mixing prevention sheet attached to a lower side of a handrail frame via a hanger rail.   The handrail device in a nuclear power plant according to claim 1, wherein the handrail is one of a retractable type, a removable type, and a fixed type.   The handrail device in a nuclear power plant according to claim 2, wherein the retractable handrail includes a bracket movable portion installed at the periphery of the spent fuel pool so that the handrail frame can be folded and supported in one end direction. .   The bracket movable part has a pair of upper and lower front inclined direction elongated holes and a pair of left and right holes formed by drilling an arcuate guide hole extending from the upper end of the elongated hole located on the upper side toward the front lower side. And the upper butterfly bolt that inserts and fixes the lower end of the leg portion of the handrail frame between the two plate materials, and the long hole located on the lower side of both plate materials, and rotates the lower end of the leg portion of the handrail frame. A fixing lower butterfly that is inserted into a long hole having a guide hole that is positioned above both plate members and a support bolt that is supported so as to be movable, and is integrated with the lower end of the leg portion of the handrail frame. After the lower wing nut is loosened and the handrail frame is lifted upward, the lower wing nut and the support bolt are slid upwardly along each elongated hole, and then the lower part around the support bolt. While sliding the side wing nut along the arc-shaped guide hole Handrail device in a nuclear power plant according to claim 3 tilting the sliding frame.   With a retractable pole standing on the base and the bracket movable part so that the spent fuel pool with the handrail frame removed can be used as an alternative to the handrail frame by dividing it with a safety rope. The handrail device in a nuclear power plant according to claim 3 or 4, further comprising: a fixed pole that stands upright; a retractable pole; and a safety rope that is inserted into a ring at an upper end of the fixed pole.   At the upper side of the handrail frame, hooks for hanging the jig and hooks for hanging the float are attached, and the shielding plate inside the handrail frame has precautions for easy-to-see surroundings, radiation signs, etc. The handrail device in a nuclear power plant according to any one of claims 1 to 5, further comprising a mounting seat for receiving a signboard.

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