The following two methods were used to prepare a total of about 1500 grams of UN: nitriding the metal powder and nitriding a ndxture of UO/sub 2/ and C. Pellets having an average of about 94% of theoretical were obtained by sintering finely milled UN powder at 1750 deg C. Based on x-ray analysis only, good quality U/sub 3/Si/sub 2/ was prepared by reacting the elements at 1550 deg C. Pellets of U/sub 3/Si/sub 2/ having a density of about 93% of theoretical were obtained by sintering the finely milled U/sub 3/Si/sub 2/ powder at 1300 deg C. (W.L.H.)