Patent Number: 040173577
Section: claims

1. A nuclear core inlet flow arrangement for a nuclear reactor, said nuclear core comprising, in combination, a plurality of fuel assemblies including fissile material for generating heat by nuclear fission, inlet flow means for admitting reactor coolant into said nuclear core, said reactor coolant serving to remove said generated heat from said nuclear core, said inlet flow means comprising a plurality of seperate plenum flow regions, plurality of inlet flow nozzles respectively communicating with a corresponding one of said plurality of fuel assemblies for admitting and directing said reactor coolant into and through said corresponding fuel assemblies, each of said inlet flow nozzles having a plurality of parallel inlet flow path means with the respective corresponding flow path means of said plurality of nozzles in fluid communication with a corresponding one of a plurality of separate plenum flow regions from which said reactor coolant is drawn into said nuclear core for assuring the existence of an inlet flow path for said reactor coolant into said nuclear core, said plurality of parallel inlet flow path means associated with each of said nozzles being connected by a common flow channel comprising the interior of said corresponding inlet flow nozzle and an outlet means for exiting said reactor coolant from said nuclear core. 2. The system of claim 1 wheerein said plurality of plenum flow regions comprises a main flow region for supplying a first of said inlet flow path means with reactor coolant and an alternate flow plenum region for supplying a second of said inlet flow path means with said reactor coolant, said plenum flow regions being flow connected but physically separated by a perforated sealing member, said perforated sealing member having perforated openings sized to permit flow of said reactor coolant between said plenum flow regions but prevent passage of foreign objects which may block said second of said inlet flow path means.