Patent Number: 047560673
Section: description

DETAILED DESCRIPTION OF EMBODIMENT AND PRACTICE OF THE INVENTION FIGS. 1 and 1A show predominantly the lower section 31 of an LGT including old split-pin assemblies 33 and 35 which are to be replaced. The pins 33 and 35 are spaced diametrically in counterbores 37 and 39 (FIG. 2) of the flange 41 of the section 31. The lower section 31 includes a plurality of sheaths 43 secured together by cards 45. The cards 45 have coextensive openings 47 (FIG. 1A), each opening having a boundary 49 whose envelope is of generally square shape. Each sheath 43 includes a plurality of tubes 51 of generally transverse C section whose openings are in communication with opening 47. The tubes 51 accommodate control rods (not shown). The arms of the spider (not shown) from which the control rods radiate pass through the lateral opening in the tubes 51. Control-rod guides 53 are mounted in the corners of the boundary 51. Each guide 53 has a transverse slot 55 in communication with opening 47. Each slot has longitudinal arcuate expansions 56 intermediate the ends and 57 near the outer ends for accommodating control rods (not shown). The tubes 51 and the guides 53 have longitudinal slots 58 for passing the coolant. The lowermost sheath 43a is connected between the lowermost card 45a and the flange 41. The upper section 63 of the LGT has a flange 65 bolted to the flange 61 of the upper guide-tube section. The uppermost sheath 43b is connected between the uppermost card 45 and the upper flange 65 of section 63. The intervening sheaths are connected between cards 45. Each OSPA 33-35 (FIG. 2) includes an old split pin 71 having a thread 73 at one end and a bifurcated tip or tires 75 at the opposite end. A flange 77 is interposed between the thread 73 and the tip 75 extending from a shank 79 connected to the threaded end. Each OSPA 33-35 is secured in the top and bottom counterbores 37 and 39 of the flange 41 by an old nut 80 with the flange 77 engaging the base of the bottom counterbore 39 and the old nut threaded onto the thread 73 and in engagement with the base of the top counterbore. Rotation of the old nut relative to the old pin is prevented by a locking device 81 of T section which engages a slot (not shown) in the top of pin 71. The locking device is secured by a pin 82 which passes through the nut 73 and is welded to the cross member of the locking device 81. In use, the outer surfaces of the tines of the tip 75 grip the surface of a hole in the upper core support (not shown in FIG. 2). The NSPA 84 (FIG. 3) in its state prior to crimping includes a new pin 83 (FIGS. 3, 4) and a new nut 85. The new pin 83 has near one end a thread 86 which is interposed between a stem 87 having elongated grooves or flutes 88 and a shank 89. The centers of the flutes 88 are spaced by 90.degree. around the stem 87. The opposite end 91 of the new pin is bifurcated. A flange 93 is interposed between the end 91 and the shank 89. The new nut 85 includes an internally threaded section 95 from which a cylindrical head 97 extends. The head 97 has circular grooves or notches 99. Secured to the head 97 of the new nut 85 is a cup 101 (FIG. 3) having a shoulder 103 from which a skirt 105 extends. The cup 101 is precrimped to the head by indentations 107 which engage the grooves 99 in the head. As shown in FIG. 4A in the completed NSPA 110, the cup 101 is crimped into the flutes 88 in the new pin 83. Also shown in FIG. 4A is a part of the upper core plate 94 of the reactor. The tines of the new split pin 83 extend into a hole in the core plate 94 gripping the wall of the hole. In the replacement of the OSPA's 33-35 by NSPA's 110, each OSPA is broken up into fragments and removed from the LGT. The new split pins 83 are then placed on knife edges or blades on a plate of an installation tool and the guide tube is positioned on the plate with its counterbores 37, 39 in registry with the new split pin and the flange 93 of each new split pin in engagement with, or positioned to be raised into engagement with, the base of the lower counterbore 39. The new nuts 85 are then torqued onto the new split pins 83 by a runner and a torque wrench. The cups 101 are then crimped into pairs of opposite flutes 88 in the stems of the split pins. As shown in FIG. 5, the replacement of the OSPA's 33-35 by the NSPA's is accomplished in a refueling pool 111 at a depth of about 20 feet of water. An OSPA removal stand 113 and an NSPA installation stand 115 are suspended vertically typically from a wall of the pool in position so that they can perform the removal and replacement. The removal stand 113 includes a saw assembly 117 and a drill 119. The installation stand 115 includes a fixture 121 appropriately equipped for the installation. FIGS. 6A through 6N show the processing of guide tube having diametrically mounted OSPA's 33 and 35 for the removal of the OSPA's. Only the lower section 31 and part of the upper section 63 of the LGT are shown but these sections are to be taken to represent the complete guide tube. The guide tube is removed from the reactor by a crane (not shown), which engages a bail (not shown) in the top of the guide tube, and transported to the OSPA removal stand 113 (FIG. 6A) where it is suspended on blocks 125 with OSPA positioned so as to be engaged by the saw 127 of the saw assembly 117 (FIG. 6B) at or above the crotch 129 (FIGS. 2, 6B) where the tines join. Preferably, the saw should not be aligned transversely with the region where the tines are separated. This positioning is to be avoided because it is undesirable that the saw should encounter the gap between the tines. Under appropriate circumstances, it may be feasible or even desirable to sever the old pin 71 along the tines. The saw 127 is driven by an air motor 133. The air is supplied through a hose 135 connected to a compressor (not shown) on the platform (not shown) above the refueling pool 111. The air is exhausted above the pool through an air hose 137. The saw assembly 117 is pivotal in and out of engagement with the old pin 71 of the old split-pin assembly so as to free the cutting region from chips. The old pin 71 is completely severed, breaking up the OSPA into a pin fragment 141 and a second fragment 143 including the flange 77 and old nut 80 (FIG. 7B) with the remainder of the old pin attached to it. The second fragment remains in the counterbores 37 and 39 of the flange 41. The guide tube (31-63) is next rotated 180.degree. positioning OSPA 35 to be engaged by the saw 127 and the second fragment 143 of the OSPA 33 coaxially with the bit 145 of the drill 119 (FIG. 6C). The bit 145 has a diameter approximately equal to or greater than the diameter of the shank 79 of the old split pin 71. The drill is driven by an air motor 147. Air is supplied to the motor 147 by hose 149 from a compressor (not shown) on the platform over the pool 111 and the exhaust is transmitted through a hose 151 to the region above the pool. The bit 145 is driven into the second fragment 143 axially (FIGS. 6D, 7C) breaking the second fragment up into a third fragment 153 (FIG. 7D) including predominantly the flange 77 and a fourth fragment 155 including the remainder of the old pin 71 and the old nut 80. The fragments 141, 153, 155 of OSPA 33 are removed. The saw 127 now severs the old split pin 71 of the second OSPA 35 into a pin fragment 141 and a second fragment 143 (FIGS. 6E, 7B). The guide tube (61-63) is rotated through 180.degree. and the drill 119 is operated to break up the second fragment 143 into a third fragment 153 and fourth fragment 155 (FIGS. 6F, 7D). The fragments 141, 153 and 155 of OSPA 35 are removed. Each new split pin 83 is now threaded onto the end of a long-handled rod (not shown) on the platform of the pool 111 and is positioned on a knife edge 161 on the platform 163 of the installation stand 115 with the tines of the bifurcated tip 91 bridging the knife edge (FIG. 6G). The long-handled rod is then unscrewed from each new split pin 83. The guide tube (31-63) is positioned on the platform with the fluted tip 87, the threaded section 85 and the shank 89 (FIG. 4) of each extending into the top counterbore 37 and the flange 93 abutting the base of the bottom counterbore 39 (FIGS. 6H, 6I). The guide tube is appropriately positioned by pin 165 which extends through opening 47 (FIG. 1A) and pins 167 which extend through opposite expanded openings 57. A new nut 85 is threaded onto each new split pin by nut runner 171 (FIGS. 6I, 6J). Each new nut 85 is secured to the new split pin 83 by applying a predetermined measured torque with a torque wrench 173 (FIGS. 6K, 6L). The locking cup 101 of each new nut 85 is crimped to the flutes 88 in each new split pin by a crimper 175 (FIGS. 6M, 6N). The saw-and-drill stand 113 is shown in its specific aspects in FIGS. 8 through 14. The stand 113 includes a pair of elongated vertical supports 181 (FIGS. 8, 9) each formed of a plurality of coextensive overlapping angles or extensions 183 secured together by bolts. The supports 181 are suspended from an angle plate 185. The angle plate is secured to a vertical plate 189 anchored in a corner 191 of a wall 193 of the pool. The angle plate 185 carries an eyebolt 195 for manipulating the stand 113. Pads 197 are bolted to certain of the angles 183 and engage the wall 193. The pads 197 are so preadjusted that the supports 181 extend vertically along the wall. The stand 113 includes a baseplate 199. The baseplate 199 is generally C-shaped with the web 200 of the C inwardly with respect to supports 181. The baseplate 199 is rigidly supported by a strut formed of straps 201, support 203 and braces 205. The straps 201 are suspended from angles 183. The support 203 is secured to an extension 206 from the lowermost angle 183a and the braces 205 are secured between support 203 and baseplate 199. The baseplate is also secured to projections 207 extending from the lowermost angles 183a. A fixture 209 is supported on a three-sided frame 210 bounding the opening 212 (FIG. 10) in the baseplate 199. The fixture 209 is positioned on the baseplate by dowel pins 211 and is bolted to the baseplate. The fixture 209 carries the blocks 125 (FIGS. 6B, 8) on which the flange 41 of the guide tube (31-63) is disposed. Vertical guides 213 extend upwardly from the blocks 125. The fixture 209 has oppositely disposed clamps 215 for firmly securing the guide tube. The guide tube is so oriented on blocks 125 that the clamps engage the flange 41 of the guide tube at positions displaced circumferentially by about 90.degree. from each OSPA 33 and 35. The saw 127 and its drive 133 are suspended as a unit from a shaft 217 extending vertically from the fixture 209 (FIGS. 9, 10). The shaft 217 carries a gear 219 which is rotatable by a pinion 211. The pinion is rotatable by a long arm (not shown) from the platform (not shown) over the pool 111. By rotating the pinion 221 the saw 127 may be pivoted so as to permit removal of the chips. A baseplate assembly 223 is mounted on angles 183b at an upper level of the support 181. The assembly 223 includes a baseplate 225 and a pair of supporting plates 227 which are secured to brackets 229 extending from the end sides of the angles 183b. The baseplates 225 and the supporting plates 227 are bolted together. At its outer end, the baseplate 225 carries pins 231 and 233. FIG. 9 shows a fragmentary diagrammatic view of the guide tube as a whole including the upper guide tube 235 as well as the LGT (31-63). The upper guide tube 235 and the LGT (31-63) are joined by a flange 239 (FIG. 9) which has holes to receive the pins 231 and 233 so that the overall guide tube (31-63-235) is in proper position for processing. The pin 231 has a bullet-shaped tip 241 and is longer than pin 233 to facilitate mounting of the guide tube. The drill 119 (FIGS. 12, 12A, 13, 14) has a nosepiece 243 extending from a bearing housing 245 including a bearing 247. The chuck 249 carrying the bit 145 extends from a drive adapter 251 which is connected to a threaded drive shaft 253 movable forward and backward and rotatable in the bearing 247 as the shaft is driven. To drive the shaft, the air motor 147 (FIGS. 6C, 12A) is provided. The air motor 147 is supplied through pipe 261 from a compressor (not shown) on the platform above pool 111 through hose 149 connected to a nipple 259. The pipe 261 communicates with the nipple in a chamber 263, containing the control valves for the motor. The pipe 261 is connected to the motor chamber containing the turbine (not shown) of the motor. The air is exhausted to the region above the pool 111 through a hose 151 (FIGS. 6C, 12) connected to the outlet 267 (FIGS. 13, 14) of an exhaust manifold 269. The exhaust manifold 269 is a member of generally L longitudinal cross section. Within the leg of the L there is a generally cylindrical chamber 271 communicating with cylindrical openings 273. Bounding each opening 273, there is a peripheral groove within which there is an O-ring 275. The outlet 267 extends through the foot of the L and communicates with chamber 271 through a grooved generally cylindrical region 277 and a neck 279. The opening through which the grooves 279 were machined has a threaded boundary 281 and is sealed by a plug 283. The part 285 of the motor 255 which contains the turbine (not shown) and has the exhaust holes 287, extends onto the chamber 271 through the O-rings 275 (FIG. 14). The chamber 271 is sealed pressure tight by the O-rings so that the exhaust air can only flow out through outlet 267 whence it is exhausted to the region above the pool 111. The motor shaft (not shown) is connected through reduction gears 289 and 291 (FIG. 12A) to drive gears 293 and 295. Drive gear 293 meshes with gear 297 to rotate the shaft 253 and through the shaft the bit 145. Drive gear 295 meshes with gear 299. Gear 299 meshes with the thread on shaft 253 and advances or retracts the bit 145 depending on the direction of rotation of the motor shaft. The housing 263 contains a forward-stroke control valve 301 which, reverses the direction of rotation of the turbine of motor 255 on engaging stop 303 when the bit 145 is advanced, and back-stroke control valve 305 which reverses the direction of rotation of the turbine, when the bit 145 is retracted, by engaging stop 307. The nuts 306 and the engaging stop 303 serve to adjust forward-reverse motions. The drill 119 is secured firmly to the fixture plate 209 through the opening 212 in baseplate 199 (FIGS. 10, 12B). A flange 311 is mounted about the chuck 249 of the drill. This flange 311 of the drill is held between an annular flanged member 313 above the flange 311 and an annular retention member 315 below this flange. The flange 317 of the flanged member 313 is bolted to the top of fixture 209. The retention member 315 is bolted to the flanged member 313. There is a bushing 319 in member 313 through which the bit 145 passes. The installation stand 115 (FIGS. 15-19) includes a support 321 formed of a plurality of sets 323 of coextensive angles 325 joined at their ends by plates 327. The sets 323 are suspended from angle supports 329 which are themselves suspended from a block 331 connected to a plate 333 anchored to a bracket 335 in the corner 337 of the wall of the pool 111. The block 331 carries an eyebolt 339. The plate 327 and a plate 341 at the lower ends of the angles 325 carry pads 343 which engage the adjacent wall 345 of the pool 111 and are preadjusted so that the support 321 is suspended vertically. The fixture 163 includes a baseplate 347 supported on a plate 348 of generally C section. The plates 347 and 348 are supported by braces 349 extending from a pedestal 351. The braces 349 have cross plates or ears 353 upon which the plates 347 and 348 are stacked. The plates 347 and 348 and the cross plates 353 are bolted together. The plates 347 and 348 are anchored to the plates 341 of the vertical supports by triangular brackets 354. Cups 355 (FIG. 18) extend from the plate 347 and are spaced symmetrically with respect to the center of the plate along the line 356 of the plate parallel to the wall of pool 111. Within each cup 355 the knife edge or blade 161 extends from the plate 347. The pin 165 extends from the center of plate 347 and the pins 167 extend from the plate 347 spaced symmetrically with respect to the center along a line at 45.degree. to the center line 356. The pins 165 and 167 serve to position the guide tube (31-63-235) appropriately on the fixture support 163. The pin 165 extends through the center of the section 31 (FIG. 1A) of the guide tube. The pins 167 extend through oppositely diagonally disposed expansions 57 (FIG. 1A). Projections 358 extend from the surface of plate 347 (FIG. 18). The guide tube is positioned on these projections. When a guide tube is positioned on plate 347 with the pins 165 and 167 penetrating through the center and through the openings 57, its counterbores 39 (FIG. 2) extend over the blades 161 so that the new split pins placed on the blades pass through the other counterbores 37. The plate 347 is widened near the outer end and pins 357 extend from the ears resulting from the expanded width. These pins serve for positioning the mechanism of the crimping assembly 175 (FIG. 6M) for crimping the cups 101 onto the flutes 88 of the new split pins 83. A guide plate 359 of generally C-section is suspended from the support 321 by brackets 361 of triangular shape connected to joining plate 327. The guide plate 359 is mounted on baseplates 363. The plates 359 and 363 are dowelled and bolted together. The inner edge of the guide plate 359 is shaped to accommodate the guide tube (31, 63, 235). The guide plate 359 carries pins 365 and 367. These pins, like the pins 231 and 233 (FIGS. 8, 9) of the saw-and-drill stand 113, pass through holes in the flange 239 joining the upper guide tube 235 and the LGT (31-63). In the use of the installation stand 115, each new split pin 83 (FIG. 4) is positioned on the plate 347 with its tines (end 91) straddling the knife edge 161 and its flange 93 engaging the upper surface of cup 355. The mounting and torquing of the nut 85 (FIG. 3) and the crimping of the cup 101 onto the flutes 88 in the pin is then carried out. These and other operations demand auxiliary tools which will now be described. It has been found that after the fragment 143 (FIG. 7C) of the old split-pin assembly 71 (FIG. 7A) is broken up by the drill 119 into the flange fragment 153 (FIG. 7D) and the pin-and-nut fragment 155, the flange fragment adheres to the base of the counterbore 39. To remove the flange fragment, the punch 371 shown in FIGS. 20, 20A, 20B is provided. Punch 371 is a long-handled tool capable of being operated from the platform above pool 111. The punch includes a long rod composed of pipe sections 373 joined by threaded sleeves 375. A plug 377 is welded to the upper end of the uppermost section 373 when the tool is in use (reversed with respect to FIG. 20). This section also carries a handle 379. A plug 381 is also welded to the lower end of the lowermost section 373. This plug carries a generally L-shaped member whose foot is a stud 383 integral with the leg 385. The stud 383 terminates in a pin 387. In use, the tool 371 is inserted in the pool 111 with the member 383-385 at the level of the flange 41 of the guide tube (FIGS. 1, 1A, 2). Since the pin 387 is offset with respect to the rod it is readily inserted in the upper counterbore 37. By manipulation of the handle 379, the flange fragment 153 is struck and released. FIGS. 21 and 22 show the runner 171 for threading the new nut 85 on the thread 86 of the new split pin 83. This runner includes a cylindrical tube 393 extending between a plate 395 and the top of a skeletal member formed of plates or bars 398 interconnected by tie plates 399 at the ends and by tie plates 401 on the sides. A bail 403 is joined to the ends of plate 395. Within the tube 393 a cylindrical shaft 405 is rotatable. The shaft 405 is hollow but terminates at the upper end in a socket 407 having an internal hexagonal female receptacle 409 for a wrench. At the lower end, the shaft terminates in a flange 411 from which a pin 413 extends integrally forming a shoulder at the flange 411. The shaft 405 passes through a bearing 415 in plate 395 and the pin 413 passes through bearings 417 in plates 398. The shaft 405 is rotatable by a wrench (not shown) engaged in receptacle 409. The shaft 405 drives a gear 419 through pin 413. The pin 413 is keyed to the hub of the gear 419 by keys 421. A roll pin 425 passes through the lower end of the pin 413. The gear 419 drives a train of gears 427, 429, 431. Typically, the gear ratio of the gears 419 and the gear 427 with which gear 419 meshes is one-to-one and the gear ratios between the other gears of the train is also one-to-one. A pin or stub shaft 433 is joined to the hub of the last gear 431 of the train by keys 435. A retaining ring 437 is in engagement with the top of pin 433. The stub shaft 433 carries a socket 439 whose inner surface 441 is shaped to mate with the outer surface of the new nut 85 (FIG. 3). Inwardly, where the inner surface of the socket 439 is shaped to mate with the head 97 and the cup 101 of the new nut 85. The socket has grooves within which there are O-rings 443. In the use of the runner 391, a new nut 85 is inserted in the socket 439 on the platform above the pool 111. The new nut is gripped and held securely by the O-rings 443. The runner 391 is then inserted in the pool 111 and the new nut is positioned over a selected new pin 83 on a knife edge 161 on the plate 348 of the installation stand 115 (FIG. 18) with the thread of the new nut in running engagement with the end of the thread 86 of the new pin 83. The positioning is facilitated by viewing the video screen (not shown) of a closed-circuit television system whose camera 445 is set to transmit a view of the top of the new pin (FIG. 6I). The new nut 85 is then threaded onto the thread 86 by rotating shaft 405 with a wrench. The rotation of shaft 405 rotates gear 419 in turn rotating gear 431 and socket 439 through the gear train. The new nut has grooves 446 (FIG. 3) (see also FIG. 3 Nee et al. supra) and the inner surface 441 of the socket 439 is shaped to mate with the grooves so that the threading is facilitated. After the new nut is threaded so that its inner end is in contact with the base of the upper counterbore 37 (FIG. 2) in flange 41, the runner 391 is separated from the new nut by pulling upwardly on the runner. It is now necessary to torque the new nut 85 onto the new pin with a torque which must not exceed a predetermined magnitude. For this purpose the offset extension torque wrench 173 (FIGS. 23, 23A) is provided. The wrench 173 includes a long pipe 453 having a plug 455 with a hexagonal head 457 welded to its upper end. Near its lower end the pipe 453 is penetrated by an arm 459 which is welded to it. The arm 459 carries a socket 461 whose inner surface is shaped to mate with the outer surface of the new nut. In the use of the torque wrench 173 the socket 461 is engaged with a new nut 85 threaded on a pin 83 by the runner 171 and is turned by applying a predetermined measured torque to the hexagonal head 457. The pipe 453 is maintained vertical by a fixture 463 including a block having a hole in which the pipe 453 is engaged. The torque is measured at the head 457 on the platform over the pool 111 but is applied through arm 459 since an offset is demanded. However, the arm is short compared to the length of the pipe 451 so that the actual torque applied to the new nut is substantially equal to the measured torque. Typically, as shown in FIG. 23A, the length of the pipe is 20 ft. and the distance between the axis of the pipe and the axis of the socket is 7 inches. The ratio of the length of the arm to the vertical length over which the torque is applied is only 7/240; the arm length is only 0.3% of the length of the pipe so that torque applied to the new nut 85 is for all practical purposes the same as the measured torque. The crimping assembly or crimper 175 (FIGS. 24A, 24B) includes a baseplate 473 to be disposed on the flange 41 (FIG. 2) of a guide tube 123 in position on plate 347 of the installation stand 115 (FIGS. 15-19) for a crimping operation. An inner pipe 475 has a flange 477 at the bottom which is bolted centrally to the plate 473. The pipe 475 is composed of axial sections 479 firmly connected, at each junction between abutting sections, by a female adapter 481 (FIG. 24A), having a threaded opening, connected to one section and a male adapter 483 having a threaded stud 485 (FIG. 25). The stud is threaded into the threaded opening, connected to the abutting section. The uppermost section 479a has a threaded stud 485a. The stud 485a passes through an opening in a top plate 487 and is secured by a nut 489 to the top plate. Along a portion of its length the upper section 479a is passed through a sleeve 490 suspended from plate 487. A bail 491 is mounted on the top plate. The crimper 175 also includes an outer cylindrical tube or pipe assembly 493 formed of sections or extensions 495 joined axially by couplings 497. Each coupling is composed of a flange 499 on one abutting section 495 and a flange 501 on the other and an annular bushing 503 interposed between the flanges 499 and 501. The flange 501a in the uppermost coupling 497a has an extended portion 504 which has slots to receive the bolts 506 that secure the flanges and bushing 503 together. The lengths and positioning of the sections 495 of the outer pipe assembly are such with respect to the inner pipe section 479 that the couplings 497 are interposed between adapter sets 481-483. The bushing 503 of each coupling 497 slideably engages the section 479 which is radially inwardly with respect to the bushing. The upper section 479a of the inner pipe 475 and the upper section 495a of the outer pipe 493 have coaxial transverse holes near the top (FIG. 25). The holes are penetrated by a pin 511 having a ring 513 at its outer end. The pin 511, when in the holes, prevents the outer pipe from dropping downwardly. By pulling transversely on the ring 513 the pin may be pulled out. Thus, the pin 511 serves as a quick release for the outer pipe 493. The lowermost section 495b of the outer pipe carries a crimping tool 515. The crimping tool 515 includes a plate 517 extending integrally near one end from the section 495b. At its opposite end the plate 517 carries oppositely disposed crimping jaws 519. The jaws 519 are fixedly secured, or extend integrally from, the lower surface of plate 517. The jaws 519 have oppositely disposed tapered cam surfaces 521 whose contour is shaped such that when the jaws are moved downwardly in engagement with a cup 101 of a new nut 85, the cup is effectively crimped into oppositely flutes 88 of a new pin 83 to which the new nut is threaded (FIG. 4A, top). The base 473 has holes 523 and 525. The crimper 175 is positioned for a crimping operation with the base 473 on the flange 41 of the guide tube 123. The crimper is so positioned that the hole 523 in the base 473 extends over the new nut 85 of a new-nut-and-split-pin assembly 84 (FIG. 3) whose cup 101 is to be crimped into flutes 88 of a new pin, and the hole 525 penetrated by the adjacent pin 357 (FIG. 18) extending from plate 347. The assembly 84 is centered in hole 523 so that it is coaxial with the center line between the surfaces 521 of the jaws 519 and the surfaces just above or in contact with the end of cup 101. A guide pin 527 extends from base 473 and passes through a hole in arm 517. The guide pin serves to guide the crimping tool 515 as it is moved upwardly and downwardly. The crimper 175 also includes a ram 529 which is of generally I-longitudinal cross section and is hollow encircling the upper section 495a of the pipe 493 near the top. The lower flange 531 of the ram 529 rests on the surface of extension 504 of the flange 501a of the upper coupling 497a in the standby condition of the crimper 175. The upper flange 533 of the ram 529 serves for operation of the ram. In the use of the crimper 175, the crimper is positioned on the flange 41 of a guide tube (31-63-235) as disclosed above and as shown in FIG. 24. In the standby condition of the crimper 471, the ram 529 is positioned so that the flange 531 is seated on the upper section 504 of the flange 501a of the coupling 497a. The quick-release pin 511 is removed and while the outer pipe 493 is held, the ram 529 is separated from the upper section 504 of the flange 510a. The ram 529 is then released or thrust downwardly so that it strikes section 504a thrusting pipe 493 and tool 515 downwardly. Jaws 519 move downwardly so that the cup 101 of the new nut 85 is crimped into flutes 88 of the new pin 83. The ram is repeatedly raised and released or thrust a number of times so that the crimping operation is carried out effectively. The crimper 175 is then removed from the NSPA and positioned on the other split-pin and nut assembly. In this case, the base 473 is positioned so that the other new nut is centered in hole 523 and the other pin 357 is centered in hole 525. The second crimping operation is then completed. The processed guide tube is then returned to the reactor. While the automatic tooling disclosed in Calfo et al. application (supra) operates highly successfully in situations in which the OSPA's in all or most guide tubes are to be replaced, the apparatus and method of this invention has marked advantages where only a few OSPA's are to be replaced by NSPA. The automatic tooling disclosed in Calfo et al. requires seven trailer trucks of equipment whereas this invention requires only one; the automatic tooling requires 30 to 50 minutes for complete separation (breakage) of the pin, and about 4 to 5 hours for complete removal of an OSPA and installation of an NSPA. The invention requires only 2 hours for removal of an OSPA and installation of an NSPA. This invention is much less costly than the automatic system. While preferred practice and a preferred embodiment of the invention has been disclosed herein, many modifications thereof are feasible. This invention is not to be restricted except insofar as is necessitated by the spirit of the prior art.