Patent ID: 8457271

Claim:
A radioactive debris trap ( 10 ) to be installed a steam generator having a primary head for the purpose of removing debris entrained in a primary flow ( 46 ) of a nuclear power plant's primary heat transport system, the debris trap ( 10 ) comprising: an outer cylinder ( 12 ) comprising an outer surface, a top end, a bottom end, a back side and an opposite front side having a perimeter; an inner cylinder ( 14 ) located within the outer cylinder ( 12 ) and coaxial therewith, the inner cylinder ( 14 ) comprising a top end and a bottom end; a top plate ( 16 ) which connects the top end of the outer cylinder ( 12 ) to the top end of the inner cylinder ( 14 ); a plurality of small holes ( 24 ) located at the top end of the outer cylinder ( 12 ) through which liquid exits the debris trap ( 10 ), the plurality of small holes ( 24 ) being sized to ensure that the gravitational force exerted on the debris entrained in the primary flow ( 46 ) is larger than the upward drag force exerted on the debris by the flow ( 46 ) itself; an annular cavity located between the outer cylinder ( 12 ) and the inner cylinder ( 14 ), the annular cavity comprising a settling chamber ( 48 ) positioned below the plurality of small holes ( 24 ); a bottom plate ( 18 ) connected to the perimeter of the bottom end of the outer cylinder ( 12 ) which encloses the radioactive debris trap ( 10 ); a gap ( 22 a ) located between the bottom end of the inner cylinder ( 14 ) and the bottom plate ( 18 ) through which primary flow ( 46 ) with debris entrained therein enters the settling chamber ( 48 ); a means for fixedly connecting the radioactive debris trap ( 10 ) to the steam generator, the means being fixedly attached to the outer surface of the outer cylinder ( 12 ); and a means for removing the radioactive debris trap ( 10 ) from the steam generator without exposing personnel to excessive radiation.