Hold-down apparatus for fuel assemblies.

摘要

A hold-down apparatus for resiliently locating a fuel assembly (1) in the core of a nuclear reactor is incorporated in the top nozzle (2) of the fuel assembly. The hold-down apparatus comprises a plurality of hold-down devices (7) each of which is located in the top nozzle by a top plate (10) and a bottom adaptor plate (11). Included in each hold-down device (7) is a guide pin (18) extending upwardly from the adaptor plate (11) and telescopically supporting a plunger (8) at its upper end. The plunger (8), which is urged upwardly by a pair of helical springs (23, 24), extends above the top nozzle (2) for location against the upper core plate of the reactor. Thus, the hold-down devices serve to absorb hydraulic forces resulting from the flow of coolant through the fuel assembly and cater for any expansion of the fuel assembly during operation. <IMAGE>