Patent Number: 062663860
Section: claims

1. A method of performing maintenance on a nuclear reactor lower internal assembly, where said lower internal assembly is located within a reactor vessel, said method comprising the steps of: removing said lower internal assembly from said reactor vessel in an upright orientation;  inverting said lower internal assembly from said upright orientation;  performing maintenance on said lower internal assembly;  repositioning said lower internal assembly in a upright orientation; and  reinserting said lower internal assembly in said reactor vessel.  providing a spider assembly sized to fit within said cavity and which provides an outward radial force; and  installing said spider assembly within said cavity.  lifting said lower internal structure out of said reactor vessel;  positioning said lower internal assembly on said storage stand;  performing maintenance on said lower internal assembly.  positioning said lower internal assembly on said storage stand;  removing said spider assembly;  lifting said lower internal assembly off said storage stand;  lowering said lower internal assembly into said reactor vessel;  coupling said lower internal assembly to said reactor vessel.  wherein said removal step further comprises:  providing a frame assembly adapted to receive said lower internal assembly;  lifting said lower internal structure out of said reactor vessel;  positioning said lower internal assembly within said frame;  attaching said lower internal assembly to said frame.  providing a crane;  coupling said crane to said frame;  rotating said frame assembly with said crane.  providing said frame assembly with an arcuate portion;  rotating said frame assembly on said arcuate portion.  providing a storage stand;  removing said lower internal assembly from said frame assembly;  positioning said lower internal assembly on said storage stand;  performing maintenance on said lower internal assembly.  positioning said lower internal assembly in said frame assembly;  using said crane to reposition said frame assembly so that said lower internal assembly is in the upright orientation.  removing said lower internal assembly from said frame assembly;  positioning said lower internal assembly on said storage stand;  removing said spider assembly;  lifting said lower internal assembly off said storage stand;  lowering said lower internal assembly into said reactor vessel;  coupling said lower internal assembly to said reactor vessel. 2. The method of claim 1, wherein said lower internal assembly has an open ended cavity, and said removal step comprises: 3. The method of claim 2, wherein said maintenance step comprises: providing a storage stand; 4. The method of claim 3, wherein said reinserting step comprises: 5.The method of claim 2, wherein said lower internal assembly has an open ended cavity; and 6. The method of claim 5, wherein said rotating step comprises: 7. The method of claim 6, wherein said inverting step further comprises: 8. The method of claim 7 wherein said maintenance step comprises: 9. The method of claim 8, wherein said repositioning step comprises: 10. The method of claim 9, wherein said reinserting step comprises: