Patent Number: 
Section: claims

1. A positioning assembly for use in a nuclear reactor peripheral assembly, wherein the assembly comprises:a plurality of rollers configured to be supported by and moveable relative to the peripheral assembly;a mast extending between the plurality of rollers, wherein at least two of the rollers are each positioned on different sides of the mast from each other to secure the mast and create relative movement between the mast and the rollers when the rollers rotate; anda power transmission configured to provide power to the rollers. 2. The assembly of claim 1, wherein the plurality of rollers includes at least one of, three rollers evenly positioned about the mast, three rollers positioned at a 90-degree interval and two 135-degree intervals about the mast, and four rollers each positioned at 90-degree intervals about the mast. 3. The assembly of claim 2, wherein the plurality of rollers includes a first group of at least three rollers at a first position and a second group of at least three rollers at a second position separated from the first position along the mast. 4. The assembly of claim 3, further comprising:an expander joined between a roller of the first group and a roller of the second group, wherein the expander is configured to bias the roller of the first group and the roller of the second group against the mast by expanding. 5. The assembly of claim 1, further comprising:a motor connected to the power transmission configured to provide the power to the rollers. 6. The assembly of claim 5, wherein,the plurality of rollers includes a first group of rollers at a first position and a second group of rollers at a second position separated from the first position along the mast,the power transmission includes a shaft geared to the motor and extending to the first group of rollers and the second group of rollers, andthe shaft connects to and powers at least two rollers of the first group and at least two rollers of the second group. 7. The assembly of claim 1, further comprising:a sun gear through which the mast passes, wherein the sun gear is configured to secure to the peripheral assembly, and wherein the rollers and the mast are connected to an exterior of the sun gear to revolve around the sun gear. 8. The assembly of claim 7, further comprising:a motor connected to the exterior of the sun gear so as to power the revolving of the rollers and mast around the sun gear. 9. The assembly of claim 1, wherein the mast is at least one of, a rope or cable having a round perimeter, and a rigid pole having a quadrilateral perimeter, further comprising:an instrument attached to the mast. 10. A peripheral assembly for use in a nuclear reactor, wherein the assembly comprises:a clamp configured to clamp on opposite sides of a steam dam in the nuclear reactor, wherein the clamp allows circumferential movement of the assembly on the steam dam; anda positioning assembly supported by the clamp, wherein the positioning assembly includes,a plurality of rollers moveable relative to the clamp,a mast extending between the plurality of rollers, wherein at least two of the rollers are each positioned on different sides of the mast from each other to secure the mast and create relative movement between the mast and the rollers when the rollers rotate, anda power transmission configured to provide power to the rollers. 11. The assembly of claim 10, wherein the plurality of rollers includes at least one of, three rollers evenly positioned about the mast, three rollers positioned at a 90-degree interval and two 135-degree intervals about the mast, and four rollers each positioned at 90-degree intervals about the mast. 12. The assembly of claim 11, wherein the plurality of rollers includes a first group of at least three rollers at a first position and a second group of at least three rollers at a second position separated from the first position along the mast. 13. The assembly of claim 12, further comprising:an expander joined between a roller of the first group and a roller of the second group, wherein the expander is configured to bias the roller of the first group and the roller of the second group against the mast by expanding. 14. The assembly of claim 10, further comprising:a motor connected to the power transmission configured to provide the power to the rollers. 15. The assembly of claim 14, wherein,the plurality of rollers includes a first group of rollers at a first position and a second group of rollers at a second position separated from the first position along the mast,the power transmission includes a shaft geared to the motor and extending to the first group of rollers and the second group of rollers, andthe shaft connects to and powers at least two rollers of the first group and at least two rollers of the second group. 16. The assembly of claim 10, further comprising:a sun gear through which the mast passes, wherein the sun gear is configured to secure to the peripheral assembly, and wherein the rollers and the mast are connected to an exterior of the sun gear to revolve around the sun gear. 17. The assembly of claim 16, further comprising:a motor connected to the exterior of the sun gear so as to power the revolving of the rollers and mast around the sun gear. 18. The assembly of claim 10, wherein the mast is at least one of, a rope or cable having a round perimeter, and a rigid pole having a quadrilateral perimeter, further comprising:an instrument supported by the mast and moveable relative to the clamp through movement of the positioning assembly. 19. The peripheral assembly of claim 10, further comprising:an inspection arm radially extendable from at least one of the clamp and the positioning assembly; anda utility end on the inspection arm configured to secure to an instrument. 20. The assembly of claim 19, further comprising:a drive rod extending vertically upward from the clamp, wherein the drive rod connects to and moves one of, the clamp circumferentially on the steam dam, the clamp vertically relative to the steam dam, and the inspection arm radially, and wherein the drive rod is moveable vertically to connect to and move only one of the clamp and the inspection arm.