Nuclear reactor fuel assembly with improved top nozzle and hold-down means

摘要

A nuclear reactor fuel assembly having an improved top nozzle subassembly with a hold-down device incorporated therewithin to prevent the force of the upward coolant flow from lifting the fuel assembly into damaging contact with the upper core support plate, while allowing for changes in fuel assembly length due to core-induced thermal expansion. The construction of the fuel assembly is such that its top surface can be placed in direct contact with the upper core plate. Thermal expansion of the components of the fuel assembly in the upward direction are accommodated within the top nozzle subassembly.