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A debris trap is mounted within a bottom nozzle of a fuel assembly so as to capture and retain debris carried by coolant flowing from the lower core plate openings of the nuclear reactor to the fuel assembly. The trap includes a hollow enclosure disposed below the adapter plate of the bottom nozzle

A debris trap is mounted within a bottom nozzle of a fuel assembly so as to capture and retain debris carried by coolant flowing from the lower core plate openings of the nuclear reactor to the fuel assembly. The trap includes a hollow enclosure disposed below the adapter plate of the bottom nozzle and between the corner legs of the nozzle. The enclosure is composed of upper and lower walls and a continuous side wall which spaces apart the upper and lower walls and interconnects their peripheries so as to form a debris capturing and retaining chamber within the hollow enclosure. The walls are composed of a material, such as wire mesh screen, which is permeable to liquid coolant but impermeable to debris. A plurality of wall sections severed from the lower wall and bent into the chamber of the enclosure define a plurality of openings into the chamber. The openings and wall sections which define them are oriented relative to the direction of coolant flow through the enclosure such that any debris which enters the chamber through the openings will be substantially detered from exiting back through the openings. Also, leaf springs are attached to opposite sides of the enclosure and engagable with a pair of corner legs of the bottom nozzle for releasably locking the trap enclosure in place in the bottom nozzle. Further, a central annular sleeve mounted between the upper and lower walls of th enclosure bolsters the structural integrity of the debris trap.

대표청구항 ▼

In a fuel assembly for a nuclear reactor including a plurality of nuclear fuel rods, at least one grid supporting said fuel rods in an organized array, an end nozzle having a central transverse adapter plate disposed adjacent said grid and a lower end of said fuel rods with a series of coolant flow

In a fuel assembly for a nuclear reactor including a plurality of nuclear fuel rods, at least one grid supporting said fuel rods in an organized array, an end nozzle having a central transverse adapter plate disposed adjacent said grid and a lower end of said fuel rods with a series of coolant flow holes defined therethrough which allow liquid coolant flow through said end nozzle and into said fuel assembly, a trap for capturing and retaining debris carried by said coolant flow to prevent entry of debris into said fuel assembly, said debris trap comprising: (a) a hollow enclosure disposed across said end nozzle adjacent to said transverse adapter plate and on an opposite side thereof from said grid, said enclosure being composed of material formed into a wire mesh screen which is permeable to the liquid coolant but impermeable to debris carried by the coolant; (b) said hollow enclosure having upper and lower walls extending across said end nozzle, spaced apart and interconnected at their peripheries so as to define a debris capturing and retaining chamber within said enclosure, one of said upper and lower walls being disposed adjacent to said adapter plate and the other of said walls being disposed away from said adapter plate; and (c) means on said hollow enclosure defining at least one opening into said chamber of said enclosure through said other of said upper and lower walls disposed away from said adapter plate, said opening defining means being disposed in a predetermined positional relationship with respect to the direction of coolant flow such that debris carried by said liquid coolant flow which enters said chamber of said enclosure through said opening will be substantially detered from exiting through said opening; (d) said opening defining means on said other wall including a wall section which is connected to said other wall, disposed at an angle to said other wall and the direction of coolant flow and is displaced at an inner edge from said other wall, so as to define said opening between its inner edge and said other wall in a plane extending generally parallel to the direction of coolant flow through said hollow enclosure and so as to define a path along which the debris must move in order to enter said chamber through said opening in a direction substantially transverse to the direction of coolant flow through said hollow enclosure.