Patent Number: 052951677
Section: summary

FIELD OF THE INVENTION This invention generally relates to an apparatus which is supported by and transportable along a refueling bridge of a nuclear reactor. In particular, the invention is directed to an apparatus for storing and coupling extension poles used to manipulate a tool at a remote location inside a boiling water reactor and supporting the coupled poles during assembly, transport and manipulation of the tool. BACKGROUND OF THE INVENTION During disassembly and servicing of a boiling water reactor, some activities must be performed underwater at depths of 40 to 60 feet. These activities are typically performed from the refueling bridge which spans the reactor cavity. Hollow, thin-walled poles are frequently used to reach the reactor components. These poles (each about 10 feet long and 2 to 4 inches in diameter) are usually stored on the refueling bridge. In order to reach the desired depth underwater, a number of poles are connected in series until the total length of the assembly is sufficient to allow one end of the assembly to be manipulated while the other end supports the tool at the desired depth. These poles are conventionally assembled on the bridge. Different diameter poles are used, with the larger-diameter poles being for high-torque activities. This system for storing, assembling and manipulating service poles on a refueling bridge suffers from a number of disadvantages. First, in order to reach the desired depth underwater, a number of poles need to be available to be coupled. The poles are usually stored by laying them down on the refueling bridge walkway prior to assembly and after disassembly. Poles stored in this way can obstruct other activities, present a hazard to personnel walking on the bridge, become tangled with ropes and lines, and spread contamination on the refueling bridge. Second, small-diameter, lightweight poles, which are typically used for underwater work, are very flexible and difficult to position when connected in long assemblies. Also, they cannot transmit the significant amount of torque which is required for some tools and operations. The poles also become very contaminated on the inside and are difficult to clean. Third, assembly and disassembly of a multiple-pole assembly requires much handling and holding of the pole sections. Holding and handling the weight of the pole assembly is tiring for operating personnel. During assembly or disassembly of the poles, it is possible for a pole to slip out of the operator's hands and into the cavity. Fourth, when using poles for a torquing operation, either a T-bar or a second person is required to hold the pole steady. Lastly, some underwater servicing operations require three or more people working along side each other in close proximity on the refueling bridge walkway. The close proximity of the workers causes congested working conditions and reduces individual visual observation of the underwater work. SUMMARY OF THE INVENTION The present invention is a service pole caddy system which overcomes the foregoing disadvantages of the conventional apparatus. This service pole caddy system was designed to provide a convenient means to store, assemble and disassemble service poles and to provide an auxiliary platform to perform the underwater work. In addition, the system provides a standard set of poles to perform most of the tasks and eliminates many of the problems historically experienced by servicing crews. In accordance with the preferred embodiment of the invention, the service pole caddy system comprises a rail truck-mounted rigid frame which supports a pole storage caddy, a set of standard service poles, a pole assembly work station and a motorized monorail pole hoist. A detachable auxiliary personnel work platform can be mounted on the rigid frame adjacent to the pole assembly work station. The hoist is used to convey the pole sections back and forth from the storage caddy to the work station for assembly and disassembly as required. The hoist is also used to support the weight of the pole assembly for in-vessel work. The entire rigid frame can be rolled along the refueling bridge to a desired location. The service pole caddy system provides a convenient vertical storage rack for storing service poles away from other servicing activities. The stored poles are easily accessible for assembly. Since the rack is positioned over the pool of coolant inside the reactor cavity, any excess water on the poles drains back into the pool, thereby keeping contaminated liquids off of the refueling bridge. Also, storing the service poles in a dedicated rack hanging off of the refueling bridge avoids the undesirable condition wherein the work area on the bridge walkway becomes cluttered with service poles. The service pole caddy system further comprises a passive pole support and assembly work station having means adapted to couple with a neck on a pole end connector of each of the service poles. In particular, these means comprise a two-position slotted keyway plate. A first position allows the pole to be lowered by the hoist until the next pole connector is lined up in the keyway. The operator then manually pushes the pole into a second position where the neck of the pole can be rested on a tapered support seat. The operator then causes the hoist to slacken, thereby transferring the load of the multi-pole assembly to the keyway plate, and removes the pole handling connector. The next pole is then removed from the caddy and connected to the pole supported by the keyway plate of the assembly station. Without disengaging the hoist from the last-assembled pole, the operator raises the multi-pole assembly to take the load off the keyway plate, pushes the multi-pole assembly until the pole intersecting the keyway is aligned in the first position. The operator then lowers the multi-pole assembly until the neck of the last-assembled (i.e., top) pole is lined up with the keyway and pushes the last-assembled pole into the support (i.e., second) position. This process is repeated until the pole assembly is complete. This feature eliminates the need for any mechanical latches, collars, or clamp devices. The pole assembly cannot be easily dropped, since it is either hooked to the hoist or supported in the assembly station keyway. The pole assembly work station on the service pole caddy system has a guided keyway feature to provide lateral restraint during torquing operations. The pole is vertically located in the guided keyway such that the full body diameter of the pole is within the key. The pole is thus prevented from moving laterally, allowing one-man torquing capability without the use of a T-bar. The service pole caddy system features a detachable auxiliary personnel platform. When used, the platform allows workers to position themselves adjacent to and/or across from each other when performing underwater work. Less congestion and more working room allows more efficient performance with less visual interference around the work area.