Patent Number: 055330754
Section: description

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 2 and 3, a preferred embodiment of the alignment device of the invention is illustrated. FIGS. 2 and 3 also show a spent fuel container which basically corresponds to that discussed above in connection with FIG. 1 and elements of which are identified by the same reference numerals in FIGS. 2 and 3 with primes attached. The alignment device, which is generally denoted 20, includes a lightweight plate 22 which is fitted over the access opening 14' in the cover or lid 12' of the container 10'. Plate 22 is supported on cover 12' by a mounting arrangement including a plurality of pin holes 24 formed in plate 22 and a plurality of pins 26 disposed on the upper surface of cover 12'. It will be appreciated that the pins can be provided on plate 22 and the pinholes provided in cover 12' (as described below in connection with FIG. 4) and that other mounting arrangements can also be used. Plate 22 acts as a foundation or support for the installation and use of a laser 28. Thus, the main purpose of the mounting arrangement, i.e., the pins and pinholes of the exemplary embodiment being discussed, is to orient the laser 28 with respect to the centerline of the access opening 14' of the cover 12' of the spent fuel shipping container 10'. An O-ring 30 is installed on the underside of plate 22 around the periphery thereof. The plate 22 includes a viewing window 32 (not shown in FIG. 2) which enables visual observation of the laser beam for targeting purposes and a laser aperture or laser admittance window 34 (best seen in FIG. 2) disposed beneath laser 28 and through which the laser beam is transmitted. Plate 22 also preferably includes a pair of opposed handles (not shown) for permitting manual installation and removal thereof. Laser 28 preferably comprises a low power (approximately 0.5 mw) helium neon (HeNe) laser or visible diode laser. Such lasers are commercially available, self-contained and powered from batteries or a small 115 V a.c. adapter. An example of a suitable helium neon laser is that made by Melles Griot of Irvine, Calif. identified as Model 05 LLR 881 while an example of a suitable visible diode laser is the Model No. 06 DAL 001 (and 06 DAL 001/A) produced by the same manufacturer. A snap-in mount (not shown) is available as an accessory to enable fixed mounting of the laser device 28. The snap-in mount is attached to plate 22 with suitable fasteners (not shown). The mount for the laser 28 is shown schematically in the drawings and is generally denoted 36 in FIGS. 2 and 3. It is noted that a suitable mount is described in more detail in connection with FIG. 4. A suitable laser target 38 is incorporated into the top surface of each of the fuel pockets 16' of the spent fuel shipping container 10' during the container assembly process. The targets 38 are preferably reflective grooves or strips which provide enhanced reflection of the incoming beam. In the exemplary embodiment illustrated in FIGS. 2 and 3, the targets 38 are provided on the slanted shoulders 40 (FIG. 2) of the pockets 16'. A conventional indexing ring arrangement, represented by ring 42 (FIG. 3), is provided on the top of container 10' to indicate the proper angular position of cover 12' as is described in more detail below. In operation, prior to use of the system of the invention, the operability of the laser 28 is checked, as is the condition of the O-ring 30 on the bottom of plate 22. The laser 28 is mounted into the mount (indicated schematically at 36) and the perpendicularity of the laser 28 to the plate 22 is confirmed. A closure plug (not shown) is removed from the access opening 14' of the cover or lid 12' and the laser 28 is installed over the opening 14' and energized. The cover 12' of container 10' is then rotated and the laser beam is viewed through the viewing window 32 (see FIG. 3). Proper indexing is indicated when the reflection of the laser beam brightens because of the enhanced reflection provided by the target groove 28. The index ring arrangement 42 (FIG. 3) at the top of the container 10' permits identification of the azimuth reading which corresponds to the fuel pocket in question. Referring to FIG. 4, a further embodiment of the invention is shown. In FIG. 4, the cover is denoted 12" while elements similar to those of FIGS. 2 and 3 are given the same reference numerals with primes attached. In general, FIG. 4 simply illustrates some of the elements of FIGS. 2 and 3 in more detail, although there are also some differences. In FIG. 4, the support plate 22' is provided with pins or dowels (one of which, denoted 26', is shown) while the cover 12" includes the corresponding pinholes or recesses (one of which, denoted 24', is shown). More importantly, in accordance with this preferred embodiment, a single access window, denoted 32' is employed which provides both a laser mount and viewing access. As illustrated, window 32' is mounted in a recess 42' in plate 22' and secured to plate 22' by capscrews 44. Laser 28' is mounted by a mounting arrangement generally denoted 36' and including a support cage 46 and an L-shaped mounting bracket 48 secured to plate 22'. FIG. 4 also illustrates one of two gripping handles, denoted 50, which were mentioned above and which are located on opposite sides of plate 22'. It will be appreciated that the operation of the embodiment of FIG. 4 is basically the same as that of the embodiment of FIGS. 2 and 3. Although the present invention has been described relative to specific exemplary embodiments thereof, it will be understood by those skilled in the art that variations and modifications can be effected in these exemplary embodiments without departing from the scope and spirit of the invention.