SPACE GRID INSERT

摘要

A nuclear reactor fuel assembly has a series of spacer grids (12) along its length. The grids have limited movement relative to a guide tube (10), that is the central instrument guide tube. At least one insert is located in a spacer grid concentrically about the central guide tube. The insert has a shoulder (22) along its upper end and is positioned about central guide tube. A sleeve lies between two adjacent spacer grids. The grids include saddles in the form of projections contacting the tube. The shoulder (22) maintains downward engagement of the insert with the adjacent grid. Upward engagement is ensured by a collar.