Apparatus and method for loading pellets into fuel rods

An apparatus for loading cylindrical fuel pellets into tubular fuel rods which are adapted for use in a nuclear reactor, and comprising

• rod support means for supporting a plurality of tubular fuel rods in a laterally aligned arrangement,
• pellet support means positioned adjacent one end of said rod support means for supporting a plurality of longitudinal columns of fuel pellets, with the columns being longitudinally aligned with respective ones of the rods on said rod support means, said pellet support means including guide surface means for each of said columns which is adapted for supporting a plurality of serially arranged and longitudinally oriented cylindrical pellets, and such that the pellets are adapted to be slideably and longitudinally advanced along said guide surface means to define an advancing column of pellets, and
• transition guide means positioned between said pellet support means and said rod support means for guiding the advancing columns of pellets into respective ones of said rods, said transition guide means including pellet segregation means disposed adjacent the end of each of said guide surface means for permitting each advancing pellet having a cross-sectional diameter equal to a predetermined minimum diameter to advance thereacross while permitting each advancing pellet having a cross-sectional diameter less than the predetermined minimum diameter to drop to a level below the level of the remaining pellets in the advancing column, each of said pellet segregation means including a pair of laterally separated and longitudinally extending parallel guide rails adapted to support the advancing column of pellets therebetween, and with the guide rails being laterally separated a predetermined distance so as to support each pellet of said predetermined minimum diameter while permitting a pellet of undersize diameter to drop therebetween to a level below the level of the remaining pellets in the column, and further including lateral shoulder means for precluding the further longitudinal advance of each such dropped pellet and the trailing pellets in the associated column, said lateral shoulder means being disposed adjacent and below the downstream end of said guide rails and at a level such that the advancing pellets of predetermined minimum diameter pass freely above said shoulder means while any undersize pellet which has dropped below the level of the remaining pellets is engaged by said shoulder means.