Patent Number: 053234359
Section: claims

1. A support for a control rod drive housing in a boiling water reactor comprising: a first means for supporting a control rod drive; and  a second means for supporting said control rod drive, said second means disposed on said first supporting means wherein said second means is movable on said first supporting means from a support position to a non-support position, whereby said control rod drive is supported by said first and second supporting means when said second means is in said support position and said control rod drive is not supported by said first and second supporting means and can be replaced without removing said second supporting means from said first support means when said second supporting means is in said non-support position.  a plurality of first support members provided in rows on opposing sides of a lower portion of a plurality of control rod drives; and  a plurality of second support members disposed on said first support member, said second support member having a plurality of extension members for supporting said control rod drives, wherein said second support member is movable from a support position to a non-support position, whereby said control rod drive is supported by said extension members when said second means is in said support position and said control rod drive is not supported by said extension members and can be replaced without removing said second support means from said first support means when said second support means is in said non-support position. 2. A control rod drive housing support according to claim 1, wherein said first supporting means comprises a plurality of support members provided in rows on opposing sides of a lower portion of a plurality of control rod drives. 3. A control rod drive housing support according to claim 2, wherein said second supporting means comprises a plurality of second support members disposed on said first support members, each of said second support members having a plurality of extension members for supporting said control rod drives, whereby said control rod drive is supported by said extension members when said second support is in said support position and said control rod drive is not supported by said extensions members when said second support is in said non-support position. 4. A control rod drive housing support according to claim 3, wherein said second support is rotatably disposed on said first support member, whereby said extensions are moveable rotatably from said support position to said non-support position and from said non-support position to said support position. 5. A control rod drive housing support according to claim 4, wherein said of first support members have a plurality of hubs for receiving said plurality of second support members rotatably thereon. 6. A control rod drive housing support according to claim 5, wherein said second support member has a hole therethrough for receiving one of said plurality of hubs rotatably therein. 7. A control rod drive housing support according to claim 6, wherein said plurality of extension members on each of said second support member is four, each of said extension members supporting a quadrant of said control rod drive, whereby one extension from four second support members support one control rod drive. 8. A control rod drive housing support according to claim 3, wherein said first support member has a first hole therethrough and said second support member has a second hole therethrough for receiving an instrument to be supported in said control rod drive housing, said second support member having a rim extending beyond said second hole which is rotatably mounted in said first hole of said first support member, whereby said first support member supports both the second support member an said instrument. 9. A control rod drive housing support according to claim 8, wherein said plurality of extension members on each of said second support member is four, each of said extension members supporting a quadrant of said control rod drive, whereby one extension member from four second support members support one control rod drive. 10. A control rod drive housing support according to claim 1, wherein said plurality of extension members on said second support member are removable, whereby said extensions are disposed on said first support member when in said support position and are removed from said first support member when in said non-support position. 11. A control rod drive housing support according to claim 10, wherein said plurality of extension members on said second support member is two, each of said extension members supporting half of said control rod drive. 12. A support for a control rod drive housing in a boiling water reactor comprising: 13. A control rod drive housing support according to claim 12, wherein said second support is rotatably disposed on said first support member, whereby said extensions are moveable rotatably from said support position to said non-support position and from said non-support position to said support position. 14. A control rod drive housing support according to claim 13, wherein said of first support members has a plurality of hubs for receiving a plurality of second support members rotatably thereon. 15. A control rod drive housing support according to claim 14, wherein said second support member has a hole therethrough for receiving one of said plurality of hubs rotatably thereon. 16. A control rod drive housing support according to claim 14, wherein said plurality of extension members on said second support member is four, each of said extension members supporting a quadrant of said control rod drive, whereby one extension from four second support members support one control rod drive. 17. A control rod drive housing support according to claim 13, wherein said first support member has a first hole therethrough and said second support member has a second hole therethrough for receiving an instrument to be supported in said control rod drive housing, said second support member having a rim extending beyond said second hole which is rotatably mounted in said first hole of said first support member, whereby said first support member supports both the second support member an said instrument. 18. A control rod drive housing support according to claim 17, wherein said plurality of extension members on said second support member is four, each of said extension members supporting a quadrant of said control rod drive, whereby one extension from four second support members support one control rod drive. 19. A control rod drive housing support according to claim 12, wherein said plurality of extension members on said second support member are removable, whereby said extensions are disposed on said first support member when in said support position and are removed from said first support member when in said non-support position. 20. A control rod drive housing support according to claim 19, wherein said plurality of extension members on said second support member is two, each of said extension members supporting half of said control rod drive.