JPS645674B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel rod replacement device for a fuel assembly used in a nuclear reactor.

A large number of fuel assemblies are inserted into the core of pressurized water reactors currently in use. As shown in FIG. 1, these fuel assemblies include an upper nozzle 1 and a lower nozzle 2 arranged vertically apart, and a plurality of support grids 3 arranged between the upper nozzle 1 and the lower nozzle 2. The support grid 3 is inserted into the grid space formed by the straps of the support grid 3 at a predetermined interval, and is fixed by the fixing part of the support grid 3, and its upper and lower ends are connected to the upper nozzle 1,
It is composed of control rod guide tubes 4 each connected to the lower nozzle 2, and a large number of fuel rods 5 inserted into predetermined locations in the grid space of the support grid 3 and supported by leaf springs. . Such fuel assemblies are removed from the reactor core after burning for a certain period of time, and after undergoing various inspections, only those with no problems are reloaded into the reactor core.

However, among the fuel assemblies, in the fuel assemblies in which damaged fuel rods were detected in the various inspections, even though the number of damaged fuel rods is 1 to 2 per fuel assembly, However, it was not possible to reload the reactor core, and the fuel assemblies had to be stored in spent fuel tanks, which was extremely uneconomical.

This invention was made in view of the above circumstances,
A fuel assembly including rods (damaged fuel rods) is fixed in water in a water tank by a fuel assembly holding device with the lower nozzle positioned upward and the upper nozzle positioned downward;
Attach the positioning plate to the lower nozzle, use a cutting tool to cut the attachment part of the control rod guide tube to the lower nozzle, and remove the lower nozzle from the fuel assembly.
Grip the damaged fuel rod with the rod extraction and insertion tool, pull it out relatively from the fuel assembly by lowering the fuel assembly, and insert a rod (dummy rod) into the pulled out location using the rod extraction and insertion tool. ) and then attaching the lower nozzle to the control rod guide tube allows the damaged fuel rod to be removed from the fuel assembly, allowing the spent fuel to be transported for reprocessing. As a result, damaged fuel rods can be replaced with rods (dummy rods) for under-combusted fuel, making it possible to reload the reactor core, which can significantly reduce costs. The purpose is to provide a replacement device.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 45.
This will be explained based on the diagram. Reference numeral 11 in FIG. 2 is a fuel transfer canal (water tank) provided between the walls 12 and 12 of the spent fuel tank.
An upper fixing plate 13 is installed at a predetermined location on the upper part of the wall 1.
It is attached to 2 and 12. Upper fixing plate 13
Guide frames 14 and 15 are provided in a hanging manner, and lower fixing plates 16 and 17 are attached to the lower portions of the guide frames 14 and 15. The lower fixing plates 16 and 17 are connected to the walls 12 and 17 via the overhanging member 18.
It is fixed at 12. An operating shaft 1 is attached to each of the projecting members 18 provided on the lower fixed plates 16 and 17.
9 and 20 are connected, and the fuel transfer canal 1
From the top of 1, insert a long box wrench into the operating shaft 1.
By fitting into the upper end portions of 9 and 20 and turning these, the overhanging member 18 is extended toward the wall 12 side. Can support frames 21 and 22 are provided between the guide frames 14 and 15 to face each other. As shown in FIG. 4, a sheave 24a is attached to the upper part of the can support frames 21 and 22, respectively, and the can support frames 21 and 22 are connected to an electric winch 23 attached to the upper fixed plate 13, a sheave 24b, and a wire. Rope 25, sheave 24a, wire robe 2
5 is suspended vertically via a fixture 25a attached to the upper fixing plate 13, and is supported by a holding member 26 attached to the guide frames 14, 15. As shown in FIG. 3, this holding member 26 is rotatably attached to the guide frames 14 and 15, and its tip is connected to the cylinder mechanism 2.
It has a holding lever 28 which can be freely opened and closed by means 7. Between the can support frames 21 and 22, a can 30 is rotatably attached to the can support frames 21 and 22 around a shaft 29, and a stopper 31 is rotatably attached to the can support frames 21 and 22. It is fixedly provided by. A fuel assembly 33 including a damaged fuel rod 32 is fitted into the can 30 , and this fuel assembly 33 is fixed to the can 3 by a nozzle fixing mechanism 34 .
It is held at 0. As shown in FIGS. 10 and 11, a fixing plate 36 having a threaded rod 35 is screwed into the nozzle fixing mechanism 34. As shown in FIGS. Further, the nozzle fixing mechanism 34 is connected to a cylinder mechanism 37 rotatably attached to the side wall of the can 30, and is configured to be rotated by the cylinder mechanism 37.

The can 30 includes a worm wheel 38 attached to the shaft 29 and a worm wheel 38 rotatably provided on the side wall of the can support frame 22.
Worm 39 meshed with this worm 3
The U-shaped shaft is rotated in the water of the fuel transfer canal 11 by a rotating mechanism 42 consisting of shafts 40, 41, etc. connected to It can be fixed by a stopper 43. The stopper 43 rotates via two cylinder mechanisms 44 and 45 attached to one side of the can support frame 22, a chain 46 connected to these cylinder mechanisms 44 and 45, and a chain wheel 47 provided on the stopper 43. It is said to be free.

At the upper and lower parts of the orthogonally adjacent outer walls of the can 30, as shown in FIGS.
Two nozzle receiving mechanisms 51 and 52 are attached. The nozzle receiving mechanism 51 is shown in FIGS. 15 to 17.
It is configured as shown in the figure. That is, Kyan 3
A retaining plate 53 is attached to the base of the flange 30a of 0 with a pin 54 in a hinge shape. A long hole 55 is formed in the protrusion of the retaining plate 53.
3 is a pin 56 fitted into a long hole 55 and a link 5
7. It is connected via a pin 58 to a bracket 59 provided at the upper end of the collar portion 30a. pin 56
A yoke 62 provided at the tip of a piston rod 61 of a cylinder mechanism 60 is rotatably attached to the outer wall of the can 30 via a bracket. A notch hole 63 is formed in a portion of the flange portion 30a facing the retaining plate 53, and the retaining plate 53 is opened by the operation of the cylinder mechanism 60.
It is designed to rotate around a pin 54 between the position of the retaining plate 53 shown in the figure and the position of the retaining plate 53 shown in FIG. The nozzle receiving mechanism 52 is similar to the nozzle receiving mechanism 51, so the explanation thereof will be omitted.

Further, a nozzle pressing mechanism 64 is attached to the upper and lower parts of the can 30, located at the upper right corner in FIG. This nozzle pressing mechanism 64
As shown in FIG. 18, the bell crank 66 is rotatably attached to the base of the collar portion 30a via a pin 65, and the bell crank 66 is rotatably attached to the upper end of the bell crank 66 via a pin 67. A press plate 68, a bracket and a pin 6 are attached to the outer wall of the can 30.
A yoke 71 is rotatably attached via a piston rod 9 and is provided at the tip of a piston rod 70, and a cylinder mechanism 73 is connected to a lower end of a bell crank 66 via a pin 72. Note that a notch hole 74 through which the bell crank 66 can enter and exit is formed in a portion of the collar portion 30a that faces the bell crank 66.

Further, the nozzle receiving mechanism 51 of the can 30,
On the other two outer walls opposite to the two outer walls to which 52 are attached, opposite to a support grid 75 of a fuel assembly 33, which will be described later, inserted into the can 30,
Support grid pressing mechanisms 76, 77 are attached. The support grid pressing mechanism 76 is attached to a bracket 7 provided on the outer wall of the can 30 as shown in FIG.
8, 79, a bell crank 81 rotatably attached to the bracket 78 with a pin 80, a lever 83 rotatably attached to the bracket 79 with a pin 82, and a pin 84 between the bell crank 81 and the lever 83. , 85, and a press plate 86 is rotatably attached to the bracket 79 by a pin 87, and the tip of the piston rod is connected to the bell crank 81 by a pin 88.
The cylinder mechanism 89 is rotatably connected to the cylinder mechanism 89. Further, an appropriate hole 90 is formed in the outer wall of the can 30 at a portion where the pressing plate 86 enters and exits. Note that the support grid pressing mechanism 77 is the same as the support grid pressing mechanism 76, so a description thereof will be omitted.

Note that the nozzle fixing mechanism 34 and the nozzle receiving mechanism 5
1 and 52, the nozzle pressing mechanism 64, and the support grid pressing mechanisms 76 and 77 constitute a mechanism for holding the fuel assembly 33 in the can 30.

The can 30 is reversed in the water of the fuel transfer canal 11 by the rotation mechanism 42, and the stopper 3
1,43. Therefore, Kyan 30
The inner fuel assembly 33 is fixed with the lower nozzle 91 positioned above the upper nozzle.

On the upper fixing plate 13 is an upper XY table 101.
In Fig. 20, arrows A, B; C, D (X axis,
It is provided so as to be freely movable in the Y-axis direction. upper part
The XY table 101 consists of two parallel rails 103 provided on a base 102 on an upper fixed plate 13.
In FIG. 20, the first table 10 is slidably fitted in the directions of arrows A and B (X-axis direction).
4 and 2 provided on this first table 104.
It consists of a second table 106 that is fitted onto a parallel rail 105 of the book so as to be slidable in the directions of arrows C and D (Y-axis direction) in FIG. 1st
The table 104 is screwed to a screw rod 107 rotatably attached to the base 102, and is moved in the directions of arrows A and B by the rotation of a motor 108 connected to the screw rod 107. . The second table 106 has two parallel T-grooves 106a, and is moved in the directions of arrows C and D by the rotation of a motor 110 connected to a screw rod 109 rotatably attached to the first table 104. It is made so that it can be done.

In addition, below the upper XY table 101, there is a lower
An XY table 111 is provided. this bottom
To explain the XY table 111, there are mounting bases 112 at predetermined locations on the guide frames 14 and 15.
is installed. The guide structure 1 is attached to the mounting base 112 via brackets 112a and 112b.
13 is rotatably attached around a shaft 114. The guide structure 113 is shown in FIGS.
As shown in FIG.
are slidably fitted. A pair of sliding bodies 11
8 are connected by a guide bar 119, and a positioning metal fitting 121 having a V-groove 120 is slidably fitted into the guide bar 119. Sliding body 11
Reference numeral 8 indicates a worm 122 rotatably attached to the mounting base 112, a worm wheel 123 provided on the mounting base 112, a shaft 124, chain wheels 125 and 126 wound around a chain 143, and a shaft 1.
27. By rotating the shaft 130 provided on the worm 122 via two sets of chain wheels 128 provided on the guide structure 113 and a chain 129 wound around the chain wheels 128 and connected to the sliding body 118. In Fig. 22, arrow E,
It is said to be movable in the F direction. The positioning fitting 121 also includes a worm 131 rotatably attached to the mounting base 112, a worm wheel 132 provided on the mounting base 112, a shaft 133, a bevel gear 134 attached to this shaft 133, and a worm wheel 132 mounted on the mounting base 112. The meshed bevel gear 135, the spline shaft 136 of the bevel gear 135 rotatably and slidably penetrated by one sliding body 118, the chain wheel 137 spline-fitted to this spline shaft 136, and the other sliding body 118. Chain wheels 137 are rotatably attached, and positioning metal fittings 1 are wound around these chain wheels 137.
By rotating a shaft 139 provided on the worm 131 via a chain 138 connected to the worm 21, the worm 131 can be freely moved in the directions of arrows G and H in FIG.

The mounting base 112 also includes a bracket 112a,
112b, two rotating plates 140 via the shaft 114
are rotatably attached, and these rotating plates 140
is connected to the guide frame 1 via the cylinder mechanism 141.
4 and 15. In addition, the rotating plate 140
The guide structure 1 is connected to the cylinder mechanism 142 through the cylinder mechanism 142.
13 are connected to each other, and when the cylinder mechanism 141 is extended and the cylinder mechanism 142 is contracted, the guide structure 113 rises.

A tool mounting plate 151 is fitted into the T-groove 106a and attached to the second table 106 of the upper XY table 101 so that its position can be adjusted freely. As shown in FIG. 26, a housing shaft 152 is attached to the tool mounting plate 151 via a pinion 153 and a rack 154 so as to be vertically movable. pinion 1
A shaft 156 having a handle 155 and rotatably attached to the tool mounting plate 151 is connected to the shaft 53 . A drive shaft 157 is fitted into the housing shaft 152 so as to be freely rotatable by a motor 158 and connected to a lever 159 provided on the housing shaft 152 so as to move up and down when the lever 159 is rotated. . Drive shaft 157
is fitted into the housing 161 at the lower end of the
A cutting tool 162 is also removably attached via a spacer 160. Housing 161
is detachably attached to the housing shaft 152. Spacer 160 is urged upward by a spring. The drive shaft 157 is urged upward by a spring 163 and the housing shaft 15
2 and the spacer 160, the upward movement is stopped. A chip collection device 164 is connected to the housing 161, and a communication hole 165 communicating with the chip collection device 164 is formed.

On the other hand, the can 30 is inserted into the can 30, and the can 3
A positioning plate 171 is placed above the lower nozzle 91 of the fuel assembly 33 which is held at zero and is fixed in water with the lower nozzle 91 positioned above the upper nozzle. A guide hole 173 is formed in the positioning plate 171 so as to face the control rod guide tube 172 . The positioning plate 171 is provided with two clamping plates 174 that are brought into contact with the side surfaces of the lower nozzle 91, as shown in FIGS. 25 and 26. Holding plate 174 in positioning plate 171
A clamping claw 176 is rotatably attached to the opposite side via a shaft 177 via a bracket 175, respectively. In addition, the positioning plate 171
A guide pin 178 is erected at the center of the guide pin 178 . As shown in FIGS. 27 to 31, the guide pin 178 has large diameter portions 179 and 180 with a circular cross section located at both ends, a small diameter portion 181 with a circular cross section and a generally oval cross section located in the middle thereof. It has a medium diameter portion 182. In addition, the guide pin 178
A guide body 183 is fitted to be vertically slidable. A recess 184 is formed in the guide body 183. This recessed portion 184 includes a small diameter portion 185 with a circular cross section located at the lower end, an oval hole portion 186 with an oval cross section located at the upper end, and a medium diameter portion 187 with a circular cross section slightly larger than the small diameter portion 185. It has a large diameter part 188 having a slightly larger diameter than this middle diameter part 187 and having a circular cross section. A disk-shaped spacer 189 is fitted into the middle diameter portion 187 . Spacer 1
89 has a substantially oval-shaped oval hole 190.
A hole consisting of a circular hole 191 and a circular hole 191 is formed. Further, a groove 192 is formed on the upper surface of the spacer 189. The spacer 189 is urged upward by a spring 193 fitted into the small diameter portion 185. 25 and 2 on the outer circumferential surface of the lower end of the guide body 183, the two parts facing the clamping claws 176 are
As shown in FIG. 6, one end of each link 194 is rotatably attached via a shaft 195. The other end of the link 194 is rotatably attached to the upper end of the clamping claw 176 via a shaft 196. Then, the guide body 183 is connected to the positioning plate 171.
When separated from and above the link 194
The clamping claw 176 is located at the position indicated by the two-dot chain line in FIG.
distance from. The guide body 183 is the positioning plate 17
1, the link 194 and the clamping claw 176 are in the position shown by the solid line in FIG. It is done like this. A hanging tool 19 is provided in the oval hole 186 and large diameter portion 188 of the guide body 183.
7 is removably inserted. A recess 197a having a circular cross section is formed at the lower end of the hanger 197. Further, a collar 1 that fits into the oval hole 186 of the guide body 183 is provided on the outer periphery of the lower end of the hanging tool 197.
98 is provided, and a protrusion 199 is formed on the lower surface of the hanger 197 to fit in and out of the groove 192. A hanging ring 197b is provided at the upper end of the hanging tool 197.

In addition, in order to pull out the damaged fuel rod 32 from the fuel assembly 33 fixed in the water of the fuel transfer canal 11 and insert the dummy rod 200 in its place, the upper
A positioning jig 201 is installed on the second table 106 of the XY table 101 instead of the tool mounting plate 151.
It is fitted into the groove 106a and attached so that its position can be freely adjusted. The guide ring 2 is attached to the positioning jig 201.
02 is attached, and the tool connecting tube 203 is inserted through the positioning jig 201 and the guide ring 202 so as to be able to move up and down. As shown in FIG. 34, a suspender 205 having a hole 204 is connected to the upper end of the tool connecting pipe 203. A load cell 206 is fitted into the hole 204. Further, a pipe 207 is fitted into the tool connecting pipe 203 so as to be movable up and down.
This pipe 207 is inserted through the hanging tool 205 and connected to the hanging tool 205 via a load cell 206. A rod extraction and insertion tool 208 is provided at the bottom of the tube 207.

The rod extraction/insertion tool 208 is constructed as shown in FIGS. 35-39. That is, a cylinder mechanism 212 is attached between support plates 210 and 211 of the first lever 209, and a wire guide roller 213 and a roller 214 are attached to the tip of the piston rod via a bracket. This roller 214 is the first lever 20
It is fitted into a long hole 215 formed in 9 so as to be vertically movable. The first lever 209 also has a roller fitting hole 2 formed slightly below the elongated hole 215.
A wire guide roller 217 is fitted into 16 and rotatably attached. first lever 20
A bolt 218 is installed in the vicinity of the lower end of the lever 9, and links 220, which are provided on both sides of the first lever 209,
220 is rotatably attached. A second lever 222 having a slope 221 formed at its upper end is fitted between the links 220, 220. The upper part of this second lever 222 is connected to the first lever 2
It is removably fitted into a long hole 215 and a groove 223 formed in 09. Also, the second lever 2
A long hole 224 into which the wire guide roller 217 is loosely fitted is formed in the upper part of the wire guide roller 22 . A recess 22 is provided at the L-shaped lower end of the second lever 222.
5 is formed, and a third lever 226 is fitted into this recess 225. The lower part of the third lever 226 and the lower part of the first lever 209 are overlapped in a crosswise manner and are rotatably connected to each other by a pin 227. Both the lower end of the second lever 222 and the upper part of the third lever 226 are connected to the links 220 and 2.
20 are rotatably connected via a pin 228 provided between them. Further, the lower end of the second lever 222 and the links 220, 220 are rotatably connected via a pin 229. In addition, link 2
20, 220, the first lever 209 and the third lever 226 are provided with springs 23.
0 is attached in a compressed state.

The wire guide rollers 213 and 217 include
Wire 23 with one end attached to support plate 211
1 is wound around the wire 231, and the other end of this wire 231 is attached to a wire fixture 232 attached to one side of the second lever 222. Further, as shown in FIGS. 35 and 36, the lower ends of the first lever 209 and the third lever 226 have recesses with a circular cross section into which the damaged fuel rod 32 is inserted when the lower ends are aligned. 233 is formed. Incidentally, reference numerals 234 and 235 shown in FIG. 4 are fuel rod guides in which the damaged fuel rods 32 that have been pulled out are fitted and temporarily stored, and are attached to the guide frame 15.

In addition, when inserting the dummy rod 200 into the location where the damaged fuel rod 32 was pulled out from the fuel assembly 33 fixed in the water of the fuel transfer canal 11, a positioning tool is used from the second table 106 of the upper XY table 101. The tool 201 is removed and the tool guide 241 is attached to the second table 106.
This tool guide 241 is constructed as shown in FIGS. 41 and 42. That is, the guide main body 242 is attached to the second table 106. One side and the bottom of the guide body 242 are open. The guide body 242 has two guide bodies 243 made of long L-shaped members spaced apart and parallel to each other.
and is attached in a hanging manner. The two guide bodies 243 are guided to the positioning metal fittings 121 provided on the lower XY table 111 via guide metal fittings 244, and are connected to connecting metal fittings 245 at predetermined locations.
are connected by. The guide body 242 has bosses 246 and 247, and the boss 246 has bosses 246 and 247.
A shaft member 249 is screwed onto a nut 248 which is rotatably fitted and attached to the shaft member 46 and is movably provided. Two supporting plates 251 and 251 are attached to the shaft member 249 via a shaft 250 so as to face each other. Two drum-shaped drive rollers 252, 252 are rotatably attached between the two support plates 251, 251 via shafts 253, 254. The two drive rollers 252, 252 are connected to the shaft 2
53 and 254, and are interlocked to rotate via two pulleys 255 attached to one end of the pulleys 53 and 254, and a belt 256 wound around these pulleys. axis 25
A motor (rotary drive machine) 260 is connected to the other end of the motor 3 via a pulley 257, a belt 258, and a pulley 259. Also, the boss 247 includes the boss 2
A shaft member 262 screwed into a nut 261 rotatably attached to 47 is movably provided. Two supporting plates 264 are attached to the shaft member 262 via a shaft 263 so as to face each other. 2
Two drum-shaped drive rollers 265 are rotatably attached between the support plates 264 via shafts 266 and 267. The distance between the driving rollers 252 and 265 can be adjusted to an appropriate distance by moving the shaft members 249 and 262. Tables 268 and 269 are attached to predetermined locations of the two guide bodies 243. The stand 268 has shafts 270, 270
Hinges 271, 271 are rotatably attached to the hinges 271, 271, and hourglass-shaped guide rollers 272, 273 are rotatably attached to the hinges 271, 271. Further, hinges 275, 275 are rotatably attached to the stand 269 via shafts 274, 274, and hourglass-shaped guide rollers 276, 277 are rotatably attached to the hinges 275, 275. The guide rollers 272 and 273 are each fitted on the shaft 270 and connected to the base 268 and the hinge 27.
1, the guide rollers 276, 27
It is biased towards the 7 side. In addition, the guide roller 27
6 and 277 are urged toward the guide rollers 272 and 273 by torsion coil springs (biasing members) 281 that are fitted onto the shaft 274 and engaged with the base 269 and the hinge 275, respectively. In addition,
Support plate 210 of rod extraction and insertion tool 208,
Guide rollers 282 and 283 are rotatably attached to 211 as shown in FIGS. 35 and 36. These guide rollers 282, 283
is fitted into the guide body 243 to prevent the rod extraction/insertion tool 208 from coming off the guide body 243.

Also, between the upper fixing plate 13 and the lower fixing plate 16, there is a support 291 as shown in FIGS. 32 and 4.
is rotatably attached. The support 291 is connected to the support 29 shown in FIG.
4 are connected. A camera holder 29 having a television camera 295 for overall monitoring is mounted on the pillar 294.
6 is attached so that it can move up and down. A wire (not shown) is attached to the camera holder 296, and by winding this wire around a winding drum 298 attached to the upper fixed plate 13 and rotating the winding drum 298, the camera holder 296 can be moved. It is designed so that it can be moved up and down. The television camera 295 is rotated by rotating the column 291 on the upper fixed plate 13, and the link 29 is rotated on the upper fixed plate 13.
By moving 2,293, horizontal movement is possible. In addition, the upper fixing plate 1
3, a cylinder mechanism 299 is rotatably attached. A connecting pipe 301 is attached to the end of the cylinder mechanism 299 in a hanging manner.
A television camera 302 for monitoring is suspended from the upper part. Therefore, the television camera 302 is moved horizontally by the operation of the cylinder mechanism 299,
Further, the arm 299 can be rotated by rotating it on the upper fixing plate 13.

Note that each cylinder mechanism is connected to a pipe, and these pipes are appropriately communicated with an operating unit (not shown) provided on the upper fixing plate 13.
It is configured to be operated by operating this operating unit on the upper fixed plate 13. Further, the operation and operation of each of the mechanisms is performed while monitoring the television cameras 295 and 302 by moving them as appropriate.

Next, the operation of the damaged fuel rod replacement device in the fuel assembly configured as described above will be explained.

To extract the damaged fuel rod 32 from the fuel assembly 33 containing the damaged fuel rod 32, the lower nozzle 91 is positioned and fixed above the upper nozzle in the water of the fuel transfer canal 11.

For this purpose, a long box wrench is lowered from above the upper fixing plate 13, and this box wrench is fitted onto the upper ends of the actuating shafts 19 and 20, and these are rotated to loosen the projecting members 18 of the lower fixing plates 16 and 17, respectively. The lower fixing plates 16 and 17 are fixed to the wall 12 by extending toward the wall 12 side.

Next, the cylinder mechanisms 141 and 142 of the lower XY table 111 are operated to remove the guide structure 113.
to stand up.

Next, the cylinder mechanism 27 of the holding member 26 is operated to open the holding lever 28, and the electric winch 23
Operate the wire rope 25, sheep 24a,
Can support frames 21, 2 via 24b
2 is raised or lowered to position the upper end of the can 30 at 7 m or less above the water surface of the fuel transfer canal 11, the cylinder mechanism 27 is operated to close the holding lever 28, and the holding member 26 is used to secure the can support frames 21, 22. The can support frames 21 and 22 are supported by supporting the projections provided on the holding levers 28 by the holding levers 28.

Next, the cylinder mechanism 37 is operated to knock down the upper nozzle fixing mechanism 34 and open the upper end of the can 30.

Next, the fuel assembly 33 containing the damaged fuel rods is suspended by a pit crane (not shown) provided above the spent fuel tank and transferred to the fuel transfer canal 11.
The nozzle 91 is then transferred underwater, positioned directly above the can 30, lowered and inserted into the can 30, and the lower nozzle 91 is placed on the fixing plate 36 of the lower nozzle fixing mechanism 34.

Next, the holding plates 53 of the nozzle receiving mechanisms 51 and 52
While the can 30 is held upright, the cylinder mechanisms 73 of the nozzle pressing mechanisms 64 provided on the upper and lower sides of the can 30 are operated, and the upper nozzle and the lower nozzle 91 are moved by the pressing plate 68 to the nozzle receiving mechanisms 51 and 52.
It is held by pressing it against the holding plate 53 of.

Next, the cylinder mechanisms 89 of the support grid pressing mechanisms 76 and 77 are actuated to press the press plate 86 against the support grid 75 via the bell crank 81 to fix each support grid 75 to the can 30 (the cylinder mechanism 89 is When extended and retracted, bell crank 81 and lever 8
3, the press plate 86 is moved in parallel to the support grid 7
Close to and separate from 5. ). Note that the multiple cylinder mechanisms 89 operate synchronously.

Next, the cylinder mechanism 37 is operated to rotate the upper nozzle fixing mechanism 34 and position the fixing plate 36 above the upper nozzle.

Next, the electric winch 23 is operated to raise the can support frames 21 and 22, and the top of the lower nozzle 91 is located 3 m or less above the water level of the fuel transfer canal 11, and the upper and lower cylinder mechanisms 2
7 and 27 are operated in synchronization, and the upper and lower holding members 2
6, 26 and close the can support frame 21,
22 is fixed to the guide frames 14 and 15.

Next, lower a long box wrench from above the upper fixing plate 13, fit it into the hexagonal bar formed at the top of the screw rod 35, and turn the screw rod 35 to secure the fixing plates of the nozzle fixing mechanisms 34, 34. The fuel assembly 33 is fixed between 36 and 36.

Next, on the upper fixing plate 13, the shaft 41 is
A motor (not shown) connected to this shaft 41 is actuated to rotate the can 30 through the shaft 40, the worm 39, the worm wheel 38, and the shaft 29.
In FIG. 1, it is rotated in the direction of arrow I and reversed.
Thereby, the lower nozzle 91 is located above, and the upper nozzle is located below the lower nozzle 91. Note that between the time when the can 30 starts rotating and the can 30 is reversed, the cylinder mechanisms 44 and 45 are operated synchronously, the stopper 43 is reversed, and the opening of the can 30 is opened as shown in FIG. position it on the right side.

Next, each pair of stoppers 31, 31 is attached to the can 3.
These stoppers 31, 31
The can 30 is held between the can 30 and rotation of the can 30 is prevented. Thereby, the fuel assembly 33 is fixed in the water.

To remove the lower nozzle 91 from the fuel assembly 33, lower a long box wrench from above the upper fixing plate 13, fit it into the hexagonal bar formed at the top of the screw rod 35, and turn the screw rod 35 to remove the nozzle. Loosen the fixing plate 36 of the fixing mechanism 34.

Thereafter, the cylinder mechanism 37 is operated to collapse the nozzle fixing mechanism 34 and open the upper end of the can 30.

Next, the lower end of the hanging tool 197 is fitted into the oval hole 186 and the large diameter part 188 of the guide body 183, and the protrusion 199 is fitted into the groove 192.
Rotate the hanging tool 197 90 degrees against the
7 is suspended using a pit crane, etc. Then, the collar 198 attaches the large diameter portion 1 to the upper part of the guide body 183.
80 respectively engage with spacers 189, and these spacers 189 engage with guide body 183 against the force of spring 193. As a result, the hanging tool 19
A positioning plate 171 is suspended together with 7. At this time, the guide body 183 and the positioning plate 171
Separate from. In this state, the positioning plate 171 together with the hanger 197 is positioned above the lower nozzle 91 above the upper nozzle, and the fuel transfer canal 1
The lower nozzle 91 of the fuel assembly 33 is fixed in water with the uppermost part located 3 m or less below the water surface of the fuel assembly 33.
Place it on top. At this time, the clamping plate 174 is
5 and 26, it is brought into contact with the side surface of the lower nozzle 91. Next, when the hanging tool 197 is pushed down, the guide body 183 comes into contact with the positioning plate 171, and the link 194 pushes the upper part of the clamping claw 176 in the direction of arrow J in FIG. Rotate to. Thereby, the lower nozzle 91 is clamped by the clamping plate 174 and the clamping claw 176, and the positioning plate 171 is fixed to the lower nozzle 91. Here, the hanging tool 197
90° relative to the guide body 183. At this time, the guide pin 178, the guide body 183, the spacer 18
9. The hanging tool 197 is in the positional relationship shown in FIGS. 27 to 31, and the spacer 189 is attached to the guide pin 1.
The guide pin 178 is prevented from rising relative to the guide pin 78 by the medium diameter portion 182 of the guide pin 178. Further, the guide body 183 is connected to the spring 193 with respect to the positioning plate 171.
Since the clamping claws 176 are pressed against each other by the force of , rotation of the clamping claws 176 is locked. Thereafter, the hanging tool 197 is pulled up, pulled out from the guide body 183, and removed from above the lower nozzle 91.

Next, the motors 108 and 110 are operated to
Move the XY table 101 and cut the cutting tool 162.
is positioned directly above the guide hole 173 of the positioning plate 171.

Next, the handle 155 is turned to lower the housing shaft 152 and the lower end of the housing 161 is fitted into the guide hole 173. and motor 158
is operated to rotate the cutting tool 162, and the lever 159 is further operated to lower the cutting tool 162 to cut the upper surface of the simple screw 92 screwed into the lower nozzle 91. As a result, the welded portion of the detent pin 93, which is fitted into the groove of the simple screw 92 and welded to the lower nozzle 91, is cut and removed. Chips during cutting pass through the space between the housing 161 and the cutting tool 162 and the communication hole 165, and are collected by the chip collection device 1 shown in FIG.
It is sucked into 64 and recovered. The locking pin 93 is collected by this chip collection device 164 after cutting. After the locking pin 93 is collected, the simple screw 92 is loosened by turning it using a nozzle removal tool 94 shown in FIG. 43, and is removed from the lower nozzle 91. That is, the nozzle removal tool 94 has a long connecting rod 95 connected to a tool 95a that fits into the groove of the simple screw 92.
Turn the upper end of the tool 95a to rotate the simple screw 92 from the lower nozzle 91. Thereafter, the simple screw 92 is collected by suction using a suction tool (not shown).

Next, hang the nozzle handling tool 96 shown in FIG. They are pulled up slightly, moved laterally, and temporarily stored at an appropriate location underwater in the fuel transfer canal 11. The nozzle handling tool 96 connects the actuator 100 to the tool head 99 and the nondle 100a.
By moving the tool head 99 and moving it up and down, the claw body 97 rotatably attached to the tool head 99 can be moved.
It can be rotated between the position shown by the two-dot chain line in FIG. 44 and the position shown by the solid line.

Next, to extract the damaged fuel rod 32 from the fuel assembly 33, the fuel transfer canal 11 is
The fuel assembly 33 is fixed in the water of the fuel transfer canal 11 so as to be located 3 m or less above the water surface, and the lower nozzle 91 is removed from the fuel assembly 33 using the cutting tool 162. A lifting tool 205 connected to the pipe 203 is suspended by a pit crane and carried onto the upper XY table 101. Then, the positioning jig 20
1. Insert the tool connecting tube 203 into the guide ring 202. Then, while observing the position of the rod extraction/insertion tool 208 using the television cameras 295 and 302, the upper XY table 101 is moved to position the rod extraction/insertion tool 208 above the damaged fuel rod 32 to be extracted from the fuel assembly 33. .

Next, the tool connecting tube 203 is lowered together with the rod extraction/insertion tool 208, and the shafts 130, 139 extending upward from above the upper fixing plate 13 are turned to connect the lower XY table 111.
The tool connecting tube 203 is brought into contact with the V-groove 120 of the positioning fitting 121.
03 in a vertical position and the rod extraction and insertion tool 208 is positioned directly above the failed fuel rod 32.

Next, the cylinder mechanism 212 is operated to contract it. Then, the wire 231 becomes temporarily loosened,
Since the roller 214 presses the slope 221 and the spring 230 presses the third lever 226, the second lever 222 rotates about the pin 229 in the direction of arrow L in FIG. Move to the position indicated by the two-dot chain line in the figure. At this time,
The link 220 rotates about the shaft 219 in the direction of arrow M in FIG. 36 and reaches the position shown by the chain double-dashed line in the same figure, and the pin 229 moves to the position shown by the symbol A in the same figure. Therefore, the third lever 226 rotates about the pin 227 in the direction of arrow N in the figure. This opens the tips of the first lever 209 and the third lever 226.

Next, the first lever 209 and the third lever 22
With the tip of 6 open, further insert the tool connecting pipe 20.
3 to lower the damaged fuel rod 32 into the recess 233.
After positioning, the cylinder mechanism 212 is actuated to extend it. Then, the wire 231 is pulled upward, which causes the second lever 22
2 rotates in the direction of arrow P in FIG.
lever 222, third lever 226, link 2
20 returns to its original position, the lower ends of the first lever 209 and the third lever 226 are closed, and the upper end of the damaged fuel rod 32 is sandwiched between these lower ends.

Next, the holding lever 28 attached to the guide frames 14, 15 is opened by operating the cylinder mechanism 27. Then, the electric winch 23 is operated to lower the can support frames 21 and 22 via the wire rope 25. As a result, the fuel assembly 33 is lowered together with the can 30, and the damaged fuel rod 32 held by the first lever 209 and the third lever 226 is pulled out from the fuel assembly 33. The pulling force at this time is transmitted to the load cell 206 via the rod extraction/insertion tool 208 and the tube 207, and is measured by the load cell 206.

The damaged fuel rod 32 that has been pulled out is joined by a pit crane, inserted into the fuel rod guides 234 and 235, and temporarily stored.

Next, a dummy rod 200 is inserted into the location where the damaged fuel rod 32 was pulled out from the fuel assembly 33. At this time, the positioning jig 201 is removed from the second table 106 of the upper XY table 101, and the The tool guide 241 is attached on the table 106 of No. 2.

Then, in order to insert the dummy rod 200 into the fuel assembly 33, in order to pull out the damaged fuel rod 32,
The electric winch 23 is operated to raise the fuel assembly 33 which has been further lowered from a position below the water surface to a position approximately 4.5 m above the water surface.

Next, the dummy rod 200 is attached to another rod extraction and insertion tool 208 of the same shape and size as the rod extraction and insertion tool 208, and the tool guide 241 is
The nut 24 is connected between the drive rollers 252 and 265.
8 and 261 to expand them, and insert the dummy rod 200 and the rod extraction/insertion tool 208 between these drive rollers 252 and 265. When the rod extraction/insertion tool 208 passes between the drive rollers 252 and 265, the nuts 248 and 261 are turned to narrow the gap between the drive rollers 252 and 265, and the tool connecting tube 203 is held between the drive rollers 252 and 265.

Next, motor 206 is activated. Then, the belt 258, pulleys 259, 257, shaft 253,
Drive rollers 252 and 265 rotate via the pulley 255, shaft 254, and tool connecting tube 203, sending the tool connecting tube 203 downward. Dummy rod 200 attached to the tip of the rod extraction and insertion tool 208
The dummy rod 200 passes between the guide rollers 272 and 276, expands between the guide rollers 273 and 277, and passes through the gap, and the lower end of the dummy rod 200 reaches near the top of the fuel assembly 33. Here, the rotation of the motor 260 is stopped, and the lowering of the dummy rod 200 is temporarily stopped.
Then, while monitoring with television cameras 295 and 302, the upper XY table 101 and the lower XY table 111 are moved to position the dummy rod 200 directly above the dummy rod insertion location of the fuel assembly 33.

Next, the motor 260 is operated again and the dummy rod 200 is inserted into the fuel assembly 33. At this time,
The rod extraction and insertion tool 208 is the guide roller 2
72, 276; 273, 277, the tool connecting pipe 203 passes between the guide rollers 272, 276;
73,277. Further, the force for inserting the dummy rod 200 is transmitted from the drive rollers 252 and 265 to the upper part of the load cell 206 via the tool connection pipe 203, and from the load cell 206 to the pipe 206.
It is transmitted to the dummy rod 200 via the seven-rod extraction and insertion tool 208. Therefore, the load cell 20
Since a compressive force is applied to 6, this compressive force is measured as the insertion force of the dummy rod 200 by a measuring device (not shown) connected to the load cell 206.

After inserting the dummy rod 200 into the fuel assembly 33, operate the cylinder mechanism 212 of the rod extraction and insertion tool 208 to open the lower end of the rod extraction and insertion tool 208, remove the dummy rod 200 from the rod extraction and insertion tool 208, motor 26
0 is rotated in the opposite direction to when inserting the dummy rod 200, and the tool connecting tube 203 and the rod extraction/insertion tool 2 are inserted.
08 will be raised, and then it will be lifted up by a crane. As described above, after pulling out the damaged fuel rod 32 from the fuel assembly 33 and inserting the dummy rod 200 in its place, the control rod guide pipe 172 of the fuel assembly 33 is inserted into the lower nozzle using the locking cap screw 311. 91 is attached to the nozzle handling tool 96, and is lowered onto the upper part of the fuel assembly 33 from which the damaged fuel rod 32 has been pulled out, and this lower nozzle is fitted into the control rod guide tube 172 to control the In the rod guide tube 172,
The locking cap screw 311 fitted to the lower nozzle is screwed together using a nozzle installation tool 312 shown in FIG. 45, and the end of the locking cap screw 311 is caulked to the lower nozzle. Note that the nozzle installation tool 312 is a tool 312a connected to the connecting rod 95 of the nozzle removal tool 94. As a result of the above, the damaged fuel rod 32
It becomes possible to reuse the fuel assembly 33 containing the fuel.

As explained above, according to the present invention, a water tank, a can provided underwater in the water tank and having both ends open, and a mechanism for holding a fuel assembly fitted into the can in the can underwater; A mechanism that allows the can to move up and down in the water; a rotation mechanism that rotates the can in a vertical plane; a mechanism that fixes the can to the water tank in the water; and control in a nozzle of the fuel assembly fixed in the water. A positioning plate having a plurality of guide holes formed corresponding to the rod guide tube attachment portion, a mechanism for detachably attaching the positioning plate to the underwater nozzle, and a guide for the positioning plate attached to the underwater nozzle. A cutting tool that is inserted into the hole so as to be vertically movable and rotatable, and a gripping part that removably grips the end of the rod, and is capable of pulling out the rod from the underwater fuel assembly, and removing the rod from the underwater fuel assembly. a rod extraction/insertion tool for inserting the rod into the body; a mechanism for guiding the cutting tool and the rod extraction/insertion tool to predetermined positions; and a mechanism connected to an operating section provided at the top of the water tank so as to freely monitor the water. The system consists of a television camera movably installed in the water, and a can installed underwater is fixed to the tank by operation at the top of the tank, and a fuel assembly is inserted into the can underwater. , this fuel assembly can be fixed to a can, and the can can be further fixed to a water tank by inverting this can in water and positioning a lower nozzle above the upper nozzle, and a positioning plate is attached to the lower nozzle. Attach the
The guide mechanism guides the cutting tool to a predetermined position, the position is determined by the positioning plate, and the lower nozzle is cut, thereby making it possible to remove the lower nozzle from the fuel assembly. The rod (damaged fuel rod) of the fuel assembly is grasped and pulled out from the submerged fuel assembly, and the rod (dummy rod) is grasped by a rod extraction and insertion tool, and the rod (damaged fuel rod) is grasped and removed from the submerged fuel assembly. Since it can be inserted into a fuel assembly, by attaching a predetermined lower nozzle to this fuel assembly, it is possible to reuse a fuel assembly that contains damaged fuel rods and was previously unusable. Therefore, it is possible to significantly reduce costs, and the effect is enormous.

[Brief explanation of drawings]

Fig. 1 is a partially omitted front view of a fuel assembly loaded into a conventional nuclear reactor, Fig. 2 is a partially omitted front view showing an embodiment of the present invention, and Fig. 3 is a side view of the main parts thereof. , FIG. 4 is a partially omitted side view, FIG. 5 is a diagram showing one operating state of the main parts, FIG. 6 is a diagram showing the state in which the guide frame is fixed to the fuel transfer canal, and FIG. 7 is a diagram showing the state in which the guide frame is fixed to the fuel transfer canal. Fig. 8 is a side view of the guide frame and the lower fixing plate; Fig. 9 is a plan view of the upper fixing plate;
The figure is a plan view of the lower fixing plate, Figure 10 and Figure 1.
Figure 1 shows how the can is attached to the can support frame, Figures 12 to 14 show how the fuel assembly holding mechanism is attached to the can, and Figures 15 and 16. 17 is a sectional view taken along line - in FIG. 16, and FIG.
The figure is a view in the direction of the arrow in FIG. 13, FIG. 19 is a view showing the installation state of the support grid pressing mechanism, FIG. 20 is a plan view of the upper XY table, FIG. 21 is a side view of the main part, Figure 22 is a plan view of the lower XY table, and Figure 23 is the - of Figure 22.
A cross-sectional view along the line, Figure 24 is the same as that of Figure 23.
25 is a plan view showing the state in which the positioning plate is attached to the lower nozzle, and FIG. 26 is the state in which the positioning plate is attached to the lower nozzle, the state in which the cutting tool is attached, and the cutting. 27 is a partially omitted vertical cross-sectional view showing the state of cutting by the tool; FIG. 27 is a view showing a state in which the positioning plate and the hanging tool are attached; FIG. 28 is a cross-sectional view taken along the line - in FIG. 27; The figure is a cross-sectional view taken along line XI--XI in FIG. 27, FIG. 30 is a cross-sectional view taken along line - in FIG. 27, and FIG. 31 is a cross-sectional view taken along line XI--XI in FIG. 27. Fig. 32 is a plan view thereof, Fig. 33a is a side view of the main part thereof, Fig. 33b is an enlarged detailed view of the circular part b in Fig. 33a, Fig. 33c is Fig. 33b
Fig. 34 is a partially cutaway sectional view showing the relationship between the hanging device and the load cell, Fig. 35
The figure is a front view of the rod extraction and insertion tool.
Figure 6 is a side view of the rod extraction and insertion tool, Figure 37 is a bottom view of the rod extraction and insertion tool,
Fig. 38 is a partially omitted side view of the rod extraction/insertion tool, and Fig. 39 is the XI of Fig. 36.
A sectional view taken along line XI, FIG. 40a is a front view of the main parts, FIG. 40b is a diagram showing the connection state of the guide body and positioning fitting, FIG. 40c is FIG. 40b
Fig. 41 is an enlarged partially cutaway longitudinal sectional view of the main part, Fig. 42 is an enlarged longitudinal sectional side view of the main part, and Fig. 43 shows the simple screw of the lower nozzle with the nozzle removal tool. Fig. 44 is a partially omitted vertical sectional view showing a state in which the nozzle handling tool is engaged with the lower nozzle, and Fig. 45 shows the lower nozzle's locking cap screw attached to the nozzle. It is a figure which shows the state rotated by a tool. 11...Fuel transfer canal (water tank), 12...
Wall, 13... Upper fixing plate, 16, 17... Lower fixing plate, 18... Overhanging member, 21, 22... Can support frame, 26... Holding member, 30...
... Can, 31, 43 ... Stopper, 32 ... Damaged fuel rod, 33 ... Fuel assembly, 34 ... Nozzle fixing mechanism, 42 ... Rotating mechanism, 51, 52 ... Nozzle receiving mechanism, 64 ... Nozzle pressing mechanism, 76,
77... Support grid pressing mechanism, 101... Upper XY
Table, 111...Lower XY table, 121
...Positioning bracket, 151 ...Tool mounting plate, 16
2... Cutting tool, 164... Chip collection device, 17
1... Positioning plate, 173... Guide hole, 174
...Pinch plate, 176...Pinch claw, 178...Guide pin, 183...Guide body, 194...Link, 197...Hanging tool, 200...Dummy rod, 2
01...Positioning jig, 206...Load cell,
208...Rod extraction and insertion tool, 241...
Tool guide, 252, 265... Drive roller, 2
95,302...TV camera.

Claims (1)

[Claims] 1 A water tank, a can provided underwater in the water tank and open at both ends, a mechanism for holding a fuel assembly inserted into the can in the can underwater, and a mechanism capable of vertically moving the can in the water. a mechanism for rotating the can in a vertical plane, a mechanism for fixing the can to the water tank in the water, and a control rod guide pipe attachment part of the nozzle of the fuel assembly fixed in the water. a positioning plate having a plurality of guide holes, a mechanism for detachably attaching the positioning plate to the underwater nozzle; and a mechanism for attaching the positioning plate to the underwater nozzle so as to be vertically movable and rotating. A rod puller having a cutting tool that is freely movable and a gripping part that detachably grips the end of the rod, and for pulling out the rod from the underwater fuel assembly and inserting the rod into the underwater fuel assembly. an insertion tool, a mechanism for guiding the cutting tool and the rod extraction/insertion tool to predetermined positions, and a mechanism connected to an operation section provided at the upper part of the water tank and movably provided in the water so as to be able to monitor the water. A fuel rod replacement device for a fuel assembly, comprising a television camera.