Process to reclaim UO.sub.2 scrap powder

A method for fabricating high-sinter-density UO.sub.2 pellets from UO.sub.2 scrap material comprising the steps of:

• oxidizing UO.sub.2 scrap material to form U.sub.3 O.sub.8 particles;
• reacting said U.sub.3 O.sub.8 particles with a nitric acid solution to produce a solution of uranyl nitrate;
• reacting said uranyl nitrate solution with ammonium hydroxide to-form a slurry of ammonium diuranate particles by precipitation;
• removing ammoniated water from said ammonium diuranate slurry to produce ammonium diuranate precipitate;
• calcining the ammonium diuranate precipitate to produce U.sub.3 O.sub.8 ;
• reducing the U.sub.3 O.sub.8 in a hydrogen atmosphere to form UO.sub.2 powder;
• passivating said UO.sub.2 powder by forming a hydrate compound on the surfaces of the particles of said powder;
• and
• sintering said passivated powder to form a pellet,
• wherein said precipitation is carried out in first and second stages, the pH in said first stage being less than the pH in said second stage and the amount of uranium precipitated out of said uranyl nitrate solution during said first stage of precipitation being held to no more than 67%, and said uranyl nitrate solution is reacted with ammonium hydroxide by adding ammonia in an amount determined in accordance with the following:
• Uranyl Nitrate Flow (UNH)=14.59 (R/C.sub.u)
• Ammonia Flow (NH.sub.3)=(UNH)(2C.sub.u P/238+N)
• Water Flow=(NH.sub.3) (M.sub.2 /M.sub.1 -1)
• where R is the rate of UO.sub.2 (kg/hr);
• C.sub.u is the uranium concentration (gm U/liter);
• N is the nitric acid molarity;
• P is the fraction of uranium precipitated in the first stage of precipitation;
• and M.sub.1, M.sub.2 are the dilute and concentrated NH.sub.3 molarities, respectively.