the instituto de energia atomica's metallurgy division pilot plant has been established to develop fabrication and control techniques of ceramic fuel elements, to train personnel and to acquire experience in quality control of fuel pellets. its close association with the institute's chemical engineering division, where pilot-plant development on uranium and thorium purification is carried out, affords a direct way to ascertain the influence of salt processing variables on the behavior of oxides derived from such uranium salts (ammonium diuranate and ammonium uranyl carbonate). the pilot plant, with a capacity of about 5 tons of uo sub 2 pellets per year, has ample flexibility in equipment, installations and procedures for such work, comprising uranium salts calcining, uo sub 2 reduction, uo sub 2 pellet fabrication, sintering, inspection, centerless grinding and adequate controls, both on powders and on pellets produced. it comprises several self-contained sub-units, corresponding to each particular operation, arranged in such a way that work can be carried independently and asssuring in each good control of accountablity.quality control techniques are exerted both on powder and on pellets lines. in the powders line, besides the current routine control tests, special ones have been developed and used, comprising grain size microscopy, electron scanning examination of particle shape and sedimentationtests. these controls allow fabrication of oxide powders (mainly natural uranium up to now) to meet the specifications for the particular programs that have been tackled. (atomin