Patent Number: 047175311
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and more particularly to FIG. 1 thereof, there is shown a railroad-type transport car, generally designated by the reference character 10, which is employed in a conventional manner within the nuclear reactor fuel assembly transfer system of the present invention. The transport car 10 comprises a primary, longitudinally extending, central support beam member 12 to which are fixedly secured, such as, for example, by welding or the like, at least two, longitudinally spaced, transversely extending secondary crossbeam members 14 and 16. For the purposes of this discussion, forward movement of the transport car 10, as designated by the arrow A, is considered to be in the direction leading from the reactor containment handling pool, not shown, to the spent fuel storage pool, also not shown. In this context, it is seen that the forward crossbeam 14 is fixedly secured to the upper surface of the central beam member 12 at an axial position intermediate the ends of beam 12, while the rearward crossbeam 16 is fixedly secured to the undersurface of the central beam member 12 at the trailing end thereof. Forward crossbeam 14 has upstanding, square-shaped plates 18 fixedly secured to the opposite ends thereof, while rearward crossbeam 16 has rearwardly extending, elongated plates 20 similarly fixedly secured to the opposite ends thereof. Each of the plates 18 serves as a mounting frame for a railroad-type wheel 22, while each of the substantially rectangularly shaped plates 20 serves as a mounting frame for a plurality of longitudinally spaced wheels 22. In this manner, transportation of car 10 along rails or tracks, not shown, disposed within the plant transfer tube or conduit, the reactor containment handling pool, and the spent fuel storage pool, all of which is also not shown but conventionally well-known, is facilitated. An upwardly extending, arch-shaped tie beam 24 is also provided to connect the rear ends of the car plates 20 together in order to provide the rear end of the car with the requisite amount of lateral structural rigidity. A fuel container 26, having a configuration of a substantially rectangular parallelopiped which is square in transverse cross-section, is pivotably mounted upon the transport car 10 by means of trunnions 28. The trunnions 28 are fixedly secured atop the side car plates 20 at an axial position interposed between the forwardmost set of wheels 22 mounted upon plates 20 and the rear sets of wheels 22 plates 20. In this manner, the fuel container 26 is able to be pivotably moved between its vertical or upended position at the extreme ends of its transportation travel path, and its horizontal position characteristic of its transportation through the plant transfer tube or conduit, not shown. It is noted that when the fuel container 26, which of course will contain either spent or fresh fuel assemblies during a transportation mode through the plant transfer tube or conduit between the reactor containment handling pool and the spent fuel storage pool, is disposed in its horizontal mode or disposition, the forward end of the container 26 is effectively laterally confined by means of a cradle defined by means of the forward crossbeam 14 and the upstanding wheel frames 18. In addition, a suitable latch mechanism 30 may be secured upon the forward end of central support beam 12 for retaining the fuel container 26 in its horizontal transport mode, however, for the purpose of this patent application and the present invention embodied herein, this latch mechanism 30 forms no part of the present invention. Lastly, it will be appreciated that, as viewed in FIG. 1, the lower end of the fuel container 26 is of course closed in order to retain the fuel assemblies, therein not shown, when the fuel assemblies are loaded into the fuel container 26 through means of the open upper end of the container by suitable crane or elevator apparatus, also not shown. When the fuel container 26 is then pivotably moved to its horizontal mode for transportation through the plant transfer tube or conduit, it is desired to effectively close the upper or forward end of the container 26 so as to prevent any inadvertent or undesired axial movement of the fuel assemblies out of the fuel container 26 in response to any axial loads which may possibly be impressed upon the fuel container-fuel assemblies assemblage during the horizontal transfer mode. In this regard, an upstanding fuel assembly retainer plate 32 is fixedly secured to the forward end of the transport car central beam 12 so as to effectively cover the open forward end of the fuel container 26 as the same is pivotably moved downwardly from its vertical upended, fuel load-unload mode to its horizontal transportation mode. In accordance with the present invention, there are provided upending mechanisms disposed within the reactor containment handling and spent fuel storage pools for automatically pivoting the fuel container 26 and its associated fuel assemblies between the aforenoted vertical loading-unloading and horizontal transport modes in response to the translational movement of the fuel container-fuel assemblies-transport car assemblage. With particular reference now being made to FIG. 2 of the drawings, the upending mechanism and system disposed within the spent fuel storage pool is shown as including an upender arm 34. Arm 34 is pivotably mounted upon a pivot rod 36 which is fixedly secured within the spent fuel storage pool by suitable means, not shown. A counterweight 38 is fixedly mounted upon a counterweight arm 40 which is integrally secured to the arm 34 so as to define an acute angle therewith, the counterweight 38 being disposed forwardly of the upender arm 34 as viewed in the forward direction of travel of the fuel container as designated by the arrow A. A horizontally disposed stop plate 42 is fixedly secured within the storage pool at a location rearwardly of upender arm 34, and consequently, under the weighted action of counterweight 38, upender arm 34 is normally vertically disposed against stop plate 42. Upender arm 34 extends downwardly beneath the level of stop plate 42, and the lower end of upender arm 34 is provided with a transversely extending bar 44 such that its ends project laterally outwardly from the plane of upender arm 34. The upender mechanism is disposed at an elevational level above the plane of horizontal travel of the fuel container 26 when the same is disposed within its horizontal transportation mode or orientation. A pair of brackets 46 are fixedly secured to the upper surface 48 of fuel container 26 at an axial or longitudinal location which is forwardly of the trunnions 28. Each of the brackets 46 is provided with a forwardly extending open slot 50 which is disposed at an elevational level matching that of the upender bar 44. In this manner, as the fuel container emerges from the plant transfer tube or conduit and is transported into the spent fuel storage pool, the fuel container slotted brackets 46 will engage the ends of upender arm bar 44 and be caused to automatically pivot upwardly from its horizontal transport mode to its vertical unload-load mode. This last-mentioned operational sequence may be appreciated with reference being made to FIG. 3 of the drawings wherein such movement of the fuel container 26, as caused by the upending system of the present invention, is schematically illustrated. As the fuel container proceeds from the reactor containment handling pool toward the spent fuel storage pool in its horizontal transportation mode, and in the direction of movement as designated by the arrow A, the fuel container will emerge from the plant transfer tube or conduit and approach the upender mechanism disposed within the spent fuel storage pool. In FIG. 3, the upender mechanism is schematically illustrated as including the upender pivot rod 36 and upender pick-up bar 44. The fuel container 26 is illustrated in various positions relative to the upender mechanism as exemplified, for example, by its approach position B wherein the fuel container trunnions are noted as 28'. When the fuel container is at such relative position, the fuel container upender brackets 46' are still upstream of the upender pick-up bar 44. As the fuel container 26 continues to approach the upender mechanism and the pick-up bar 44, engagement is made between the fuel container brackets 46 and the pick-up bar 44 when the fuel container trunnions are at station or position C. Continued horizontal translational movement of the railroad transport car 10 causes the corresponding translational movement of the fuel container 26 in the direction of arrow A and as illustrated by the illustrative location of the fuel container trunnions 28" at station or position D, however, as a result of the engagement of the fuel container brackets 46 with the upender pick-up bar 44, the upender arm 34, upender pick-up bar 44, fuel container 26, and fuel container brackets 46 are automatically caused to move to their upended positions denoted respectively at 34", 44", 26", and 46". In effect, then, by means of the present invention upending system, the fuel container is automatically caused to move, by means of the single translational movement of the railroad transport car 10, simultaneously through both translational and pivotable movements at the end of its travel path within the spent fuel storage pool. A horizontally disposed stop plate 54, similar to stop plate 42, is located within the lower depths of the spent fuel storage pool so as to arrest the pivotable movement of the trailing end of the fuel container 26" and thereby orient the same in its vertical mode whereby the container 26" is now made ready for its spent fuel unloading-fresh fuel loading operations by means of the suitable elevator or crane apparatus, not shown. Suitable stop means, also not shown, are provided immediately downstream of the end of the railroad rails or tracks for similarly arresting the translational movement of the transport car at the position or station D of trunnions 28". It is of course to be appreciated that the upending mechanism of the present invention is located within the spent fuel storage pool at a sufficient distance downstream from the end of the plant transfer tube or conduit extending into the spent fuel storage pool so as to in fact permit the clearance of the fuel container 26 beyond the transfer tube terminal end whereby the pivotable upending movement of the fuel container 26 may in fact be achieved. Furthermore, it is to be noted that the counterweight mechanism 38 serves the additionally desired function of maintaining engagement between the upender pick-up bar 44 and the fuel container brackets 46. If it is found in practice that this counterweighted force is required to be supplemented, suitable spring mechanisms, not shown, may be incorporated within the upender arm system so as to tend to bias the same still further toward its normally vertical mode as illustrated within FIG. 2. Another feature to be appreciated from the present invention system is that the trunnions 28 of the fuel container 26 are disposed rearwardly of the center of the fuel container as viewed along the axial length thereof. In this manner, the center of gravity is disposed to the right, or downstream, of the trunnions 28 of the fuel container as viewed, for example, in FIG. 3. As a result of this particular mounting of the fuel container upon the transport car 10, the fuel container 26 will tend to assume its horizontal transportation mode. This enhances the stability of the system, and acts in conjunction with the counterweight forces impressed upon the upending mechanism by means of counterweight 38. These forces become particularly active when the fuel container is caused to move from its vertical mode illustrated at 26" in FIG. 3 to its horizontal transport mode 26 upon completion of a fresh-fuel loading operation, and the commencement of a transport mode from the spent fuel storage pool toward the reactor containment handling pool. During the initial movement of the fuel container from its vertical mode 26" to its horizontal transport mode 26, it will of course be appreciated that the upending system of the present invention operates in precisely the same manner as described hereinabove, except in reverse, with disengagement of the upender pick-up bar 44 and the fuel container brackets 46 being achieved when the fuel container trunnions are located at station C. As has been briefly alluded to hereinbefore in connection with the general operation of the fuel transfer system characteristic of a nuclear plant, upending means must likewise be provided within the reactor containment handling pool of the plant, and in accordance with the present invention, such means is illustrated within FIG. 4. This system is operationally similar, but somewhat reversed, with respect to the upending system employed within the spent fuel storage pool, and is seen to include a pair of brackets 146 fixedly secured to the underside of fuel container 26. The brackets 146 are disposed forwardly of the fuel container trunnions 28, as considered in view of the relative direction of travel of the fuel container from the spent fuel storage pool to the reactor containment handling pool as designated by the arrow E, and include forwardly open slots 150. An upending mechanism is disposed within the reactor containment handling pool, and is seen to comprise an upender arm 134 pivotably mounted upon a pivot rod 136 which is fixedly secured within the reactor containment handling pool by suitable means, not shown. A counterweight 138 is fixedly mounted upon a counterweight arm 140 which is integrally formed with upender arm 134 so as to define therewith an obtuse angle such that the counterweight 138 is disposed below and rearwardly of upender arm 134. A horizontally disposed stop plate 142 is fixedly secured within the reactor containment handling pool at a location rearwardly of upender arm 134, and consequently, under the force of counterweight 138, the upender arm 134 is normally disposed vertically against stop plate 142. The upender arm 134 extends vertically above stop plate 142, and the upper end of arm 134 is provided with a transversely extending bar 144 such that its ends project laterally outwardly from the plane of arm 134. The upender mechanism is disposed at an elevational level below the plane of horizontal translational movement of the fuel container 26 so as not to interfere with the transportation thereof into the reactor containment handling pool, however, the upender pick-up bar 144 is disposed at an elevational level which matches that of the bracket slots 150 so as to operationally engage the same. In this manner, as the fuel container 26 emerges from the plant transfer tube or conduit into the reactor containment handling pool, the upending mechanism within the containment pool will automatically cause the leading end of the fuel container 26 to be pivoted downwardly whereby the fuel container 26 is ultimately re-oriented to its vertical fresh fuel unloading mode. This last-mentioned operational sequence may be appreciated from reference being made to FIG. 5 of the drawings wherein such movement of the fuel container 26, and the interaction with the upending mechanism within the reactor containment pool, is schematically illustrated. As the fuel container proceeds in its horizontal transport mode through the plant transfer tube or conduit and emerges from the same, the container 26 will enter the containment pool and approach the upending mechanism illustrated within FIG. 4. In FIG. 5, the upending mechanism of FIG. 4 is schematically illustrated as including the upender pivot rod 136 and the upender pick-up bar 144. The fuel container 26 is illustrated in various positions relative to the upender mechanism as exemplified, for example, by its approach position F wherein the fuel container trunnions are noted as 28'. When the fuel container 26' is at such relative position, the fuel container upender brackets 146' are still upstream of the upender pick-up bar 144. As the fuel container 26 continues to approach the upender mechanism and the pick-up bar 144, engagement is made between the fuel container brackets 146 and the pick-up bar 144 when the fuel container trunnions 28 are disposed at station or position C. Continued horizontal translational movement of the railroad transport car 10 causes the corresponding translational movement of the fuel container 26 in the direction of arrow E and as illustrated by the location of the fuel container trunnions 28" at station or position D. However, as a result of the engagement of the fuel container brackets 146 with the upender pick-up bar 144, the upender arm 134, upender pick-up bar 144, fuel container 26, and fuel container brackets 146 are automatically caused to be pivoted downwardly so as to achieve their upended positions 134", 144" , 26", and 146", respectively. A horizontally disposed stop plate 154 is located within the lower depths of the reactor containment handling pool so as to arrest the downwardly pivotable movement of the leading end of the fuel container 26" and thereby orient the same in its vertical mode whereby the container 26" is now made ready for its fresh fuel unloading-spent fuel loading by means of suitable elevator or crane apparatus, not shown. Suitable stop means, also not shown, is also provided immediately downstream of the end of the railroad rails or tracks within the containment pool for similarly arresting the translational movement of the transport car corresponding to the position or station D of trunnions 28". It is to be noted at this juncture that the aforenoted relative disposition of the trunnions 28 and the center of gravity of the fuel container likewise enhances the operational stability of the system within the reactor containment handling pool as such was characteristic of the operational modes within the spent fuel storage pool. Referring now to FIG. 6 of the drawings, a second, modified arrangement of the upending system of the present invention is disclosed. While the system of FIG. 6 is similar to that of FIG. 2 so as to be employed within the spent fuel storage pool of the fuel handling building, another system similar to that of FIG. 6 yet modified in accordance with the operational orientation of the system of FIG. 4, may likewise be provided so as to be capable of being employed within the reactor containment pool. As seen in FIG. 6, in lieu of the single dependent upender arm 34 of the embodiment of FIG. 2, the system of FIG. 6 employs a pair of laterally spaced dependent upender arms 234. In addition, in lieu of the single laterally outwardly projecting pick-up bar 44 of the system of FIG. 2, each arm 234 is provided at its lower end with a laterally inwardly projecting pick-up bar 244. The arms 234 are pivotally supported by suitable pivot rods, not shown, and are connected together by means of a transversely extending support bar 252. A pair of counterweights 238 are respectively operatively associated with each upender arm 234 through means of counterweight arms 240 integrally formed with the upender arms 234. Another modification of the system of FIG. 2 as embodied within the system of FIG. 6 resides in the disposition of the upender fuel container brackets 246 upon the sidewalls of the fuel container 226 as opposed to the same being disposed upon the upper and lower surfaces of the container. The brackets 246 are of course still provided with forwardly open slots 250 whereby the brackets 246 can operatively engage the upender pick-up bars 244. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.