JPS581721B2 - Nuclear fuel assembly gap inspection device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a nuclear fuel assembly gap inspection device.

Generally, a nuclear fuel assembly 10 is an assembly of fuel rods 20, as illustrated in FIG.

Further, the fuel rod 20 is a fuel tube filled with a large number of pellets formed by molding nuclear fuel material.

This combustion bar 20 has both ends attached to the upper tie plate 11.
and a lower tie plate 12, and are fixed by a tie rod 13 that fastens the upper tie plate 11 and the lower tie plate 12, forming a bundle-shaped nuclear fuel assembly 10.

A spacer 14 is provided in the middle of the nuclear fuel assembly 10 to keep the distance between the fuel rods 20 constant, as shown in FIG.

Further, the upper tie plate 11 of the nuclear fuel assembly 10 is provided with a hook portion 15 for vertical hanging, and the lower end of the tie plate 12 is provided with a seating portion 16 whose side surface is tapered. There is.

In this way, the fuel rods 2 arranged in the nuclear fuel rod assembly 10
0, the mutual spacing between adjacent fuel rods 20 is kept constant by the upper tie plate 11, lower tie plate 2, and spacer 14 as shown in FIG. This uniformity results in a safe and efficient fuel structure arrangement.

However, in such a nuclear fuel assembly 10, the fuel rods 20 may be deformed by irradiation during use in a nuclear reactor, resulting in bending or the like.

Changes in the mutual spacing between the fuel rods 20 due to the bending of the fuel rods 20 may cause local heating of the fuel rods 20 or breakage of the fuel tubes.

Therefore, in the nuclear fuel assembly 10, it is necessary to periodically measure the gap size, that is, the gap between adjacent fuel rods 2 over the entire length thereof, to monitor changes in the gap, and to ensure safe and efficient operation of the nuclear reactor. be.

However, the nuclear fuel assembly 10 that is taken out after being used in a nuclear reactor can be stored in a hot laboratory (a closed room for radioactivity shielding) and a fuel storage pool where water shielding can be performed without requiring a complicated removal device. Since it is stored in 50,
This gap inspection of the fuel rods 20 of the nuclear fuel assembly 10 must be performed underwater.

Conventional underwater gap inspection of the nuclear fuel assembly 10 has been carried out quite schematically using an industrial television or a periscope, and therefore has the problem of low reliability.

In addition, in the nuclear fuel rod underwater measurement device already proposed in Japanese Patent Application Laid-Open No. 50-8998, a large pressing force is applied to the fuel rods in order to give the fuel assembly an appropriate measurement attitude with respect to the measurement device. Therefore, there is a problem in that there is a risk that the fuel rod may be bent due to the measurement pressure and the surface may be damaged.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a nuclear fuel assembly gap inspection device that performs highly reliable quantitative inspection without damaging or deforming fuel rods.

To achieve the above object, the present invention comprises: an erected pedestal; a main slide that is vertically slidable along a vertical wall of the pedestal; a rotatable upper chuck for gripping the upper end; a rotatable lower chuck disposed at the lower end of the main slide for supporting the lower end seating portion of the nuclear fuel assembly; a holding device that holds a nuclear fuel assembly; a drive control device for the holding device that remotely controls the holding device to rotate the nuclear fuel assembly and move the nuclear fuel assembly in the vertical direction; A pair of parallelism detection terminals, non-measuring, which are movable independently of each other in a direction perpendicular to the axial direction of the nuclear fuel assembly and are biased so as to be in light contact with two adjacent fuel rods of the nuclear fuel assembly. A parallelism detection terminal escape mechanism that sometimes retreats the pair of parallelism detection terminals to a non-contact position; 1; parallelism detection means equipped with a sum-difference calculation type measuring device; capable of opening and closing in a horizontal plane, each lightly contacting opposing sides of the two fuel rods of the nuclear fuel assembly and biased in the opening direction; a pair of gap measurement terminals; a gap measurement terminal relief mechanism for closing the pair of gap measurement terminals to a non-contact position; and a second sum-difference calculation type measuring device for detecting the distance between adjacent fuel rods.

According to this configuration, the holding device is remotely controlled by the holding device drive control device to move the nuclear fuel assembly held by the holding device, and the parallelism detection means and the holding device drive control device move the nuclear fuel assembly into a posture relative to the gap measuring device. will be corrected.

Then, the gap measuring terminal of the gap measuring device is brought into light contact with the opposing side surfaces of the two fuel rods to detect the adjacent distance between the two fuel rods, and after the detection is completed, the gap measuring terminal is moved to close.

An embodiment of the nuclear fuel assembly gap detection device according to the present invention will be described below with reference to the drawings.

Spent nuclear fuel assemblies taken out from the reactor are carried into the water of the fuel storage pool 50 and temporarily stored in a honeycomb-shaped fuel storage rack provided at the bottom of the pool 50. The radioactivity accumulated in the area is attenuated.

Thereafter, this nuclear fuel assembly is transferred to an inspection device installed on the side wall of the pool and inspected for suitability for reuse.

As shown in FIG. 4, this inspection device consists of a pedestal 100 that is erected in the water along the side wall of the pool, and a pedestal 100 that temporarily supports the nuclear fuel assembly transferred from the fuel storage rack and brings it to the measurement position. A relay device 200 for transferring, a holding device 300 for receiving nuclear fuel assemblies from this relay device 200 and holding them at a measurement position, and a measuring device 500 for measuring various dimensions of the nuclear fuel assemblies held in this holding device 300.
It has a drive control device 600 that is provided above the water of the pool and remotely controls the relay device 200, the holding device 300, and the measuring device 500.

The relay device 200 also includes a lower pedestal 210 that holds the seating portion of the nuclear fuel assembly, an intermediate holding pawl 220 that holds the intermediate portion of the nuclear fuel assembly, and a hook portion 1 of the nuclear fuel assembly.
5 and a swing arm 230 that engages with the swing arm 230.

Further, the holding device 300 includes a steadying pawl 310 that holds the intermediate portion of the nuclear fuel assembly and restricts movement in the horizontal direction.
, a lower chuck 320 that holds the seating portion of the nuclear fuel assembly and is rotatable, and an upper chuck 330 that holds the hook portion 15 of the nuclear fuel assembly and is rotatable.

That is, in this embodiment, the nuclear fuel assemblies stored in the pool are transferred to the relay device 200 of the inspection device by a fuel transfer device (not shown) to prevent sideways movement in the water and prevent them from being exposed above the water. It has become.

As shown in FIG. 5, this relay device 200
A drive section 241 and an opening/closing drive section 251 are provided.

The swing drive unit 241 swings so as to engage the swing arm 230 with the hook portion 15 of the nuclear fuel assembly 10 carried into the relay position, and further moves the nuclear fuel assembly 10 from the relay position to the measurement position. The intermediate holding pawl 220 holding the assembly 10 and the swing arm 230 are synchronously swung.

The swing 1 drive unit 241 also moves the nuclear fuel assembly 10 that has been inspected back from the measurement position to the relay position.

The opening/closing 1 driving section 251 operates the intermediate holding pawl 220 so as to hold the outer periphery of the intermediate portion of the nuclear fuel assembly 10 and prevent lateral vibration during transfer.

The swing/drive unit 241 rotates the swing drive shaft 242 at a reduced speed via a worm, a worm gear, and a gear train, and the rotation of the swing drive shaft 242 is transmitted to a ball screw shaft 243 via a bevel gear.

A rack 244 is screwed onto this ball screw shaft 243, and can be reciprocated by rotation of the ball screw shaft 243.

This reciprocating movement of rack 244 rotates Geneva drivers 246 and 247 via pinion 245.

A Geneva wheel 248 is connected to the Geneva driver 246, and the Geneva wheel 248 is connected to the swing arm 230 via a gear.

Furthermore, the Geneva wheel 249 is connected to a relay arm 250 via a gear, and this relay arm 250 is provided with an intermediate holding pawl 220.

As shown in FIG. 6, the Geneva driver 246 and the Geneva driver 247 each have a pair of first pins 246A, 247A and a second pin 246B, which correspond to the same position with respect to the rotation angle of the pinion 245. 2
47B is planted.

The Geneva wheel 248 and the Geneva wheel 249 are coaxial, and are connected to the first pins 246A and 247A of the Geneva driver 246 and the Geneva driver 247, respectively.
and the first Geneva grooves 248A and 249A that engage with the second pins 246B and 247B, and the second Geneva groove 248.
B, 249B is provided, but Geneva wheel 24
Only the first Geneva groove 249A of 9 is the Geneva driver 2.
The first Geneva groove 248A and the second Geneva groove 248B of the Geneva wheel 248 are carved on the rotation locus of the Geneva bin at the engagement position with the first pin 247A of the Geneva wheel 248.
and the second Geneva groove 249 of the Geneva wheel 249
B are each engraved in the radial direction.

Therefore, the swing arm 230 is connected to the Geneva driver 2.
46 first pin 246A- engages and rotates in the first Geneva groove 248A of the Geneva wheel 248, thereby swinging from the standby position to the relay position, and the Geneva driver 246
The second pin 246B of the Geneva wheel 248 is engaged with and rotated by the second Geneva groove 248B of the Geneva wheel 248, thereby swinging from the relay position to the measurement position.

Furthermore, when the first pin 247A of the Geneva driver 247 engages with the first Geneva groove 249A of the Geneva wheel 249, the intermediate holding pawl 220 is relayed without being given any rotation via the relay arm 250. The second pin 247B of the Geneva driver 247
is engaged with and rotated by the second Geneva groove 249B of the Geneva wheel 249, thereby swinging from the relay position to the measurement position.

Next, the opening/closing drive section 251 is connected to an opening/closing drive shaft 252 via a gear train, and this opening/closing drive shaft 252 is connected to an intermediate shaft 253 via a bevel gear.

This intermediate shaft 253 is connected via a bevel gear 254A to a driven shaft 254 that is coaxially incorporated into the swing arm 230 and the relay arm 250, and this driven shaft 254 is provided with a cylindrical geared rack portion 254B. It is being

A pinion 255 supported by the relay arm 250 is meshed with this rack portion 254B.
The rotation of 55 causes a rack link 257 to reciprocate via a crank link 256, and a pinion 258 that meshes and rotates is connected to this rack link 257, and a pinion 259 that rotates in the opposite direction is connected to this pinion 258. ing.

The pinion 258 and the pinion 259 are provided with a pair of intermediate holding pawls 220, which are configured to open and close by rotating the opening/closing drive unit 251 in forward and reverse directions to grip the nuclear fuel assembly 10.

Note that detection shafts 261 and 262 are provided at the output ends of the swing drive unit 241 and the opening/closing drive unit 251, respectively, and these detection shafts 261 and 262 control the swing positions of the swing arm 230 and the intermediate holding pawl 220. In addition, the opening and closing positions of the intermediate holding pawl 220 can be detected and controlled.

In this relay device 200, the lower pedestal 210 is adapted to move up and down somewhat in conjunction with a main slide 311, which will be described later.

That is, the nuclear fuel assembly 10 carried to the relay position by this fuel transfer device is moved down the side of the swing arm 230 that has escaped to the standby position and the center part of the intermediate holding pawl 220 that is open at the relay position. It is supported on the lower pedestal 210.

Thereafter, by the operation of the opening/closing drive section 251, the intermediate holding pawl 2
20 is closed to hold the nuclear fuel assembly 10, and the fuel transfer device suspending the hook portion of the nuclear fuel assembly 10 is released to return it to its original position.

Next, by driving the swing drive unit 241,
The swing arm 230 is swung from the standby position to the relay position, and the locking portion of the swing arm 230 is attached to the nuclear fuel assembly 10.
the hook part 15 of.

When the swing arm 230 engages the nuclear fuel assembly 10, the lower pedestal 210 is lowered and the fuel assembly 10 is fully retained by the intermediate retaining pawl 228 and the swing arm 230 in this intermediate position.

By further driving the swing drive unit 241 from this state, the intermediate holding pawl 220 and the swing arm 230 are
The nuclear fuel assembly 1 is swung from the relay position to the measurement position.
0 to the holding device 300 at the measurement position.

FIG. 7 shows the steady rest of the holding device 300 at the measurement position, which is provided on the main slide 311 which is movable up and down along the vertical wall of the pedestal 100 after the nuclear fuel assembly 10 is gripped by the intermediate holding pawls 220 at the relay position. Claw 3
10 shows the state in which this nuclear fuel assembly 10 is delivered.

As shown in FIG. 8, this holding device 300 includes a hoisting drive unit 341 that moves a main slide 311 provided with a lower chuck 320 and an upper chuck 330 up and down along the vertical wall of the pedestal 100, and an upper chuck 33.
0 up and down with respect to the upper main slide 346, an upper chuck opening/closing drive section 371 that opens and closes the upper chuck 330, and a chuck rotation drive section 391 that rotates the lower chuck 320 and the upper chuck 330. , and a steady rest pawl opening/closing drive unit 401 that opens and closes the steady rest pawl 310.

The winding drive unit 341 rotates a winding drum 344 via a worm 342 and a worm wheel 343.

A hoisting rope 345 is wound around the hoisting drum 344, and this hoisting rope 345 is connected to an upper main slide 346, so that the upper main slide 346 can be moved up and down along the vertical wall of the pedestal 100. .

A lower main slide 348 is connected to the upper main slide 346 via a connecting pipe 347.

Further, an upper chuck box 349 is slidably provided on the upper main slide 346, and a lower chuck box 350 is fixed to the lower main slide 348.

Note that a detection shaft 35 is connected to the output end of this winding drive section 341.
1 is connected, and the output value of the winding drive unit 341 can be detected and controlled.

The upper chuck vertical drive section 361 is connected to an upper chuck vertical drive shaft 362 through a gear train, and this upper chuck vertical drive shaft 362 is connected to a ball screw shaft 363 through a gear train.

The ball screw portion of this ball screw shaft 363 is screwed to the upper chuck box 349, and the upper chuck box 349 is moved up and down relative to the upper main slide 346 by forward and reverse rotation of the upper chuck vertical 1 drive unit 361. It is designed to let you do so.

Further, this upper chuck box 349 is equipped with a pinion 364 whose movement in the vertical direction is restricted.
A rotatable bracket 365 is fixed to.

This bracket 365 is further connected to the upper chuck 330 via a pin 366, as shown in FIG.

That is, the displacement of the upper chuck box 349, which is moved up and down by the operation of the upper chuck vertical drive section 361, is transmitted to the upper chuck 330 via the pinion 364 and the bracket 365.

A detection shaft 367 is provided at the output end of the upper chuck vertical drive unit 361, so that the vertical movement of the upper chuck 330 can be detected and controlled.

The upper chuck opening/closing drive section 371 is connected to an upper chuck opening/closing drive shaft 372 via a gear train, and this upper chuck opening/closing drive shaft 372 is connected to an intermediate shaft 373 via a bevel gear.

This intermediate shaft 373 is connected to a cam shaft 374 via a bevel gear.
A grooved cam 375 is fixed to this camshaft 374.

This grooved cam 375 is adapted to swing a cam lever 376 that is swingably supported by the upper chuck box 349.

This cam follower 376 is provided with a cam follower 377, and this cam follower 377 connects the chuck shaft 379 to the upper chuck box 349 via a locking portion 318.
It is designed to move up and down.

Further, as shown in FIG. 9, an opening/closing link 381 is connected to this chuck shaft 379 via a pin 380.
This opening/closing link 381 is slidably connected to the upper chuck 330 via a pin 382.

The chuck shaft 379 is axially keyed to the pinion 364 and is slidable in the axial direction with respect to the pinion 364.

That is, one drive of the upper chuck opening/closing drive section 371 causes the chuck shaft 379 to move into the upper chuck box 3.
49, and the upper chuck 330 opens and closes relative to the bracket 365.

A detection shaft 383 is connected to the output end of the upper chuck opening/closing drive unit 371, and the degree of opening/closing of the upper chuck 330 is controlled by detection.

The chuck rotation 1 drive unit 391 is connected to an intermediate shaft 392 via a gear train such as a worm gear.
is connected to the chuck rotating shaft 393 via a gear train.

This chuck rotation shaft 393 is connected to the upper main slide 34
6 and the connecting pipe 347 and the lower main slide 348, and is connected to the pinion 394 inside the upper main slide 346, and the pinion 39
4 is connected to the pinion 364 via an idle gear.

The chuck rotation shaft 393 is connected to a pinion 395 inside the lower main slide 348, and this pinion 395 is connected to a pinion 396 via an idle gear, and the pinion 396 is a driven shaft provided in the lower chuck 320. It is fixed at 397.

That is, the upper chuck 330 is rotated by the pinion 394 and the pinion 36 by driving the chuck rotation drive unit 391.
4, and the lower chuck 320 is rotated via pinions 395 and 396 synchronously with the rotation of the upper chuck 330.

Further, the steady rest pawl opening/closing drive unit 401 is connected to a drive shaft 402 via a gear train, and the drive shaft 402 is connected to an intermediate shaft 403 via a bevel gear.

The intermediate shaft 403 is further connected to the ball screw shaft 40 via a gear.
It is connected to 4.

The ball screw portion of this ball screw shaft 404 is connected to a slide block 405, and the slide block 405 is moved back and forth by rotation of the ball screw.

Furthermore, a pair of steady rest pawls 310 are connected to the slide block 405 via a pair of left and right swing links 406, and these steady rest pawls 310 are provided in two sets, upper and lower, by an interlocking shaft 407.

In other words, the steady rest pawl opening/closing drive unit 401 is driven by the rotation of the ball screw shaft 404 and the slide block 40.
The swing link 406 is swung through the reciprocating movement of 5, and the pair of steady rest pawls 310 are opened and closed.

Note that a detection shaft 408 is connected to the output part of the steady rest pawl opening/closing drive unit 401, so that the opening/closing degree of the steady rest pawl 310 can be detected and controlled.

Further, as shown in FIG. 10, a housing 411 into which the driven shaft 397 and the lower chuck 320 are inserted is fixed to the lower chuck box 350, and this housing 411 is connected to the driven shaft via a bearing 412. 397 is rotatably supported.

At the top of this bearing 412 is a spring receiver 413.
is provided, and the spring receiver 413 and the lower chuck 32
A spring 414 is provided between the lower end of the nuclear fuel assembly 1 and the lower end of the nuclear fuel assembly 1 supported on the lower chuck 320.
0 is biased and supported vertically upward.

The inner chuck surface of the lower chuck 320 is formed into a tapered accommodating part 415, and the accommodating part 415 has the same taper angle as the seating part 16 of the nuclear fuel assembly 10. The body 10 is centered.

The nuclear fuel assembly 10 that has been transferred by the swinging of the relay device 200 to the measurement position where the holding device 300 configured as described above is provided is moved by the intermediate holding pawl 220 and the swing arm 230 of the relay device 200. In the supported state, the steady rest pawl 310 is closed by the operation of the steady rest pawl opening/closing drive unit 401, and is gripped by the steady rest pawl 310.

Next, the hoist drive unit 341 is driven to raise the lower main slide 348 and the lower chuck box 350, and the seating portion 16 of the nuclear fuel assembly 10 is supported in the accommodating portion 415 of the lower chuck 320.

In this way, from the nuclear fuel assembly 10 held by the steady rest pawl 310 and the lower chuck 320, the intermediate holding pawl 220 and the swing arm 230 are attached to the relay device 20.
It is opened by the operation of the opening/closing drive section 251 and the swing drive section 241 of No. 0 and returns to the relay position.

Next, by operating the upper chuck vertical drive unit 361, the upper chuck 330 is lowered to the hook portion 15 of the nuclear fuel assembly 10 from which the swing arm 230 has been removed, and further by operating the upper chuck opening/closing drive unit 371, the upper chuck 330 is lowered to the hook portion 15 of the nuclear fuel assembly 10 from which the swing arm 230 has been removed. 15 is locked and fixed.

In this state, by slightly raising the upper chuck vertical drive section 361, the nuclear fuel assembly 10 is suspended from the upper chuck 330 and its centripetal action is performed.

At this time, the lower chuck 320 floats up following the biasing force of the spring 414 and performs a centripetal action on the lower end of the nuclear fuel assembly 10, completely closing the steady rest pawl 310 and holding the nuclear fuel assembly 10.

As described above, the setting of the nuclear fuel assembly 10 to the holding device 300 at the measurement position is completed.

Next, FIG. 11 is an explanatory diagram showing a measuring device 500, which includes a column 501 fixed to the vertical wall surface of the pedestal 100 adjacent to the holding device 300, and a horizontal column 501 attached to the column 501. An X-table 502 and a Y-table 503 that protrude in the direction and are movable in one X direction and one Y direction, respectively, and a measuring section 504 placed on the X-table 502 and Y-table 503.
It has

The measuring section 504 is provided with a parallelism detection stage 530, a gap measuring device 540, and an outer bar measuring device 560, each of which has its mechanical parts built into a waterproof box 505.

The parallelism detection means 530 is a means for accurately operating the gap measurement device 540, and detects the inclination of the two fuel rods 20 as the measurement targets of the nuclear fuel assembly 10 with respect to the measurement section.

The gap measuring device 540 is a device that measures the gap between the fuel rods 20 of the nuclear fuel assembly 10.

An industrial television 506 is provided above the measurement unit 504, and this industrial television 506 is connected to a parallelism detection means 530.
Also, the operating state of the gap measuring device 540 with respect to the nuclear fuel assembly 10 can be observed.

That is, while the nuclear fuel assembly 10 is held at this measurement position by the holding device 300, it is rotated or moved up and down with respect to the measurement section 504, and the gap between two adjacent fuel rods 20 is measured over its entire length. It is now possible to do so.

FIG. 12 shows the drive system of the X-table 502 and Y-table 503 of this measuring device 500. The intermediate shaft 512 is connected to an X-ball screw 513 via a bevel gear.

The ball screw of the X-ball screw 513 is the X-table 50
2, and this X
- The table 502 is moved in the X direction.

Further, the Y-drive portion 521 is connected to an intermediate shaft 522 via a gear train such as a worm gear, and the intermediate shaft 522 is connected to a Y-ball screw 523 through a bevel gear and a gear train.

The Y-1 ball screw 523 is connected to the Y-table 503, and the Y-table 5 is driven by the Y-driver 521.
03 is movable in one direction.

Note that an X-detection axis 514 and a Y-detection axis 524 are connected to the output ends of the X-driver 511 and the Y-driver 521, respectively, and can detect and control the amount of movement of the X-table 502 and Y-table 503, respectively. It is said that

FIG. 13 shows the measuring mechanism of the parallelism detecting means 530. This parallelism detecting means 530 has a pair of movable units that are in light contact with two fuel rods 20 as objects of measurement and are movable independently of each other. It has a parallelism detection terminal 531.

The parallelism detection terminal 531 includes a rod 532 that is slid inside the waterproof box 505, and the rod 532 is linked to a balancer 534 via a lever 533.

One end of the balancer 534 is opened underwater to receive water pressure and cancel the water pressure acting on the parallelism detection terminal 531 via the lever 533.

Bellophrams 535 are provided at the ends of the rod 532 and balancer 534 that contact the water, and the waterproof box 50
5 Prevents water from entering the interior.

Further, a spring 534A is attached to the other end of the balancer 534.
The spring 534A applies measuring pressure to the rod 532 and the parallelism detection terminal 531 via the lever 533.

Furthermore, a cam lever 536 is brought into contact with the rear end of the rod 532, and one end of this cam lever 536 is attached to the rear end of the rod 532.
37 and is biased, and the other end is connected to a cam 538
is in contact with.

The cam 538 moves the parallelism detection terminal 531 backward when not measuring, and rotates the cam lever 536 clockwise during measurement to interrupt contact with the rod 532 and push the parallelism detection terminal 531 forward. ing.

Therefore, the cam 538 and the cam lever 536 constitute a parallelism detection terminal release mechanism.

Furthermore, a detection link 53 is located near the rear end of the rod 532.
9 is provided, and this detection link 539 is connected to a micro detection head (not shown), and the parallelism detection terminal 531
The amount of movement is transmitted to a first sum-difference calculation type measuring device such as a differential transformer, and the difference in level between the two fuel rods 20 is detected.

Based on the output value of the first sum-difference measuring device, the chuck rotation drive unit 391 of the holding device 300 is operated to move the nuclear fuel assembly 10 supported on the lower chuck 320 and the upper chuck 330 into fuel rods. 20
Rotate the nuclear fuel assembly 1 to the position where the step becomes zero.
The center line to be measured passing through the center of the cross section of 0 is made to coincide with the measurement center line.

The chuck rotation drive unit 391 can be driven based on the output value of the first sum-difference measuring device by operator operation or by automatic control using a pulse motor or the like that rotates the number of pulses corresponding to the output value. It may be something.

In this way, the parallelism detection means 530
The adjacent distance between the two nuclear fuel rods 20 whose inclination with respect to
It is measured by the gap measurement terminal 541 of.

That is, a pair of gap measurement terminals 541 that are movable independently of each other have their tips inserted into the middle of the two nuclear fuel rods 20, and the other ends are fixed to a pair of rods 542.

These pair of rods 542 are supported by the waterproof box 505 and reciprocate in opposite directions.

Bellophrams 543 are provided at both ends of the rod 542 to prevent water from entering the waterproof box 505.

One end of an L lever 544 that is swingably supported with respect to the waterproof box 505 is slidably connected to this rod 542, and a spring 545 is attached to the rod 542 between the waterproof box 505 and the L lever 544. This spring 545 applies a measuring pressure to open the gap measuring terminal 541.

An escaper 546 is attached to the other end of the L lever 544, and a cam lever 547 is connected to the escaper 546.

The cam lever 547 is brought into contact with a cam 549 by the biasing force of a spring 548.

This cam 549 is connected to the escaper 54 when not measuring.
Gap measurement terminal 54 via 6 and L lever 544
1 is in a completely closed state, and the escaper 546 is kept in a non-contact state with respect to the L lever 544 during measurement.

Therefore, a gap measurement terminal release mechanism is configured including the cam 549 and the cam lever 547.

A head 550 is provided near the other end of the L lever 544, and this head 550 comes into contact with an outer door 551 for micro detection.

This micro detection head 551 is connected to a second sum-difference calculation type measuring device and detects the distance between adjacent nuclear fuel rods 20 based on the amount of movement of the gap measurement terminal 541.

According to the nuclear fuel assembly gap inspection device according to the above embodiment, the nuclear fuel assembly 10 is given a correct measurement attitude by the holding device 300 and the parallelism detection stage 530,
The fuel rod 2 is connected with light contact pressure by the gap measuring terminal 541.
Since a gap of 0 is measured, the fuel rod 20 will not be damaged or deformed.

Further, this nuclear fuel assembly 10 is rotated and moved up and down by the holding device 300, so that the gap of any fuel rod 20 can be measured over its entire length.

Note that the drive control of the relay device 200, holding device 300, and measuring device 500 described above is controlled by observation by an operator or automatically by a drive control device 600 installed on a floor deck provided on the top surface of the pool. It looks like this.

This drive control device 600 includes a swing drive section 241, an opening/closing drive section 251, a winding drive section 341, an upper chuck up/down drive section 361, an upper chuck opening/closing drive section 371, a chuck rotation drive section 391, and a steady rest pawl opening/closing drive section 401. ,X
It is comprised of one drive section 511, one Y drive section 521, and the like.

Further, since the relay device 200, the holding device 300, and the measuring device 500 are each assembled into a unit and attached to the pedestal 100, they can be easily separated from the pedestal 100 and carried out onto the water during maintenance and inspection. It looks like this.

As described above, according to the present invention, it is possible to perform a highly reliable quantitative gap inspection without damaging or deforming the fuel rods.

[Brief explanation of drawings]

Figure 1 is a partially cross-sectional side view showing an example of a nuclear fuel assembly, Figure 2 is a cross-sectional view taken along line ``-'' in Figure 1, and Figure 3 is a cross-sectional view taken along line ``-'' in Figure 1. 4 is an overall perspective view showing an embodiment of the nuclear fuel assembly underwater inspection device according to the present invention, FIG. 5 is a perspective view showing the drive system of the relay device, and FIG.
The figure is a plan view of main parts showing the Geneva drive section of the same relay device.
The figure is a plan view showing the receiving state of the nuclear fuel assembly from the relay position to the measurement position, FIG. 8 is a perspective view showing the drive system of the holding device, FIG. 9 is a sectional view showing the upper chuck, and FIG. 10
The figure is a partially sectional side view of the lower chuck, Figure 11 is a perspective view of the measuring device, Figure 12 is a perspective view of the drive system of the measuring device, and Figure 13 is parallelism detection. A sectional view showing the means, and FIG. 14 is a sectional view showing the same gap measuring device. 10... Nuclear fuel assembly, 20... Nuclear fuel rod, 100... Frame, 200... Relay device, 210... Lower pedestal, 220...
・Intermediate holding pawl, 230...Swing arm, 241
....Owing drive section, 251 .... Opening/closing drive section, 300 .... Holding device, 310 ....
Steady rest pawl, 311...Main slide, 3
20... Lower chuck, 330... Upper chuck, 341... Winding drive unit, 346
・・・・・・Upper main slide, 348・・・・・・
Lower main slide, 361... Upper chuck vertical drive section, 371... Upper chuck opening/closing drive section, 391... Chuck rotation drive section, 401.
... Steady rest pawl opening/closing drive unit, 500...
・Measuring device, 502...X-table, 503
... Y-table, 504 ... measurement unit, 530 ... parallelism detection means, 540 ... gap measurement device.

Claims (1)

[Claims] 1. An erected pedestal; a main slide that can slide vertically along the vertical wall of the pedestal; a rotatable upper part that is disposed at the upper end of the main slide and grips the upper end of the nuclear fuel assembly; a chuck, a rotatable lower chuck disposed at the lower end of the main slide and supporting a lower end seating part of the nuclear fuel assembly, and a holding device disposed on the pedestal for holding the nuclear fuel assembly; a drive control device for a holding device that rotates the nuclear fuel assembly by remotely controlling the holding device and moves the nuclear fuel assembly in the vertical direction; A pair of parallelism detection terminals that are movable independently and are energized so as to come into light contact with two adjacent fuel rods of the nuclear fuel assembly, and the pair of parallelism detection terminals are turned off when not making measurements. a parallelism detection terminal release mechanism for retracting the parallelism detection terminals to the contact position, and a first sum-difference calculation type measuring device that detects the difference in the amount of movement when the pair of parallelism detection terminals lightly contact each of the two fuel rods. parallelism detection means; a pair of gap measurement terminals that can be opened and closed in a horizontal plane and that are in light contact with opposing sides of the two fuel rods of the nuclear fuel assembly and biased in the opening direction; A cap measuring terminal relief mechanism for closing the gap measuring terminal to a non-contact position, detecting the adjacent distance between the two fuel rods when the pair of gap measuring terminals lightly contact the opposing sides of the two fuel rods. Second to do
A nuclear fuel assembly gap inspection device comprising: a gap measuring device having a sum-difference calculation type measuring device;