Apparatus for coating nuclear fuel pellets with a burnable absorber

Apparatus for depositing a coating on nuclear fuel pellets, comprising:

• (a) a generally cylindrical drum rotatable about its longitudinal axis, the circumferential part of said drum having a portion with an open area;
• (b) an enclosed pallet having a lower screened part and a detachable upper screened part with said lower and upper screened parts spaced apart at a distance allowing said pellets to be disposed only in a single layer within said pallet between said lower and upper screened parts, said pallet disposable generally in said open area of said drum and, there disposed, removably attachable to said drum with said upper and lower screened parts facing along a general radial direction;
• (c) a chamber, said drum disposable within said chamber with the longitudinal axis of said drum oriented generally horizontally, said chamber with the disposed said drum defining a hermetically sealed unit;
• (d) means for rotating said drum about its longitudinal axis;
• (e) means for sputtering said coating on said pellets, said sputtering means, when said drum is disposed within said chamber, having a stationary, sputter-frangible, upper target disposed inside and proximate the circumferential part of said drum at a location which is above the longitudinal axis of said drum and which is at a longitudinal distance corresponding to that of said open area of said drum, said stationary upper target oriented to face generally upward and radially outward to sputter said coating onto those areas of said pellets, in said pallet on the rotating said drum, which are exposed to said stationary upper target as said pallet rotates past, said sputtering means, when said drum is disposed within said chamber, also having a stationary sputter-frangible, lower target disposed outside and proximate the circumferential part of said drum at a location which is below the longitudinal axis of said drum and which is at a longitudinal distance corresponding to that of said open area of said drum, said stationary lower target oriented to face generally upward and radially inward to sputter said coating onto those areas of said pellets, in said pallet on the rotating said drum, which are exposed to said stationary lower target as said pallet rotates past;
• and
• (f) means for controlling said drum rotating means and said sputtering means.