Optimization of Process Parameters of UO₂ Powder Production for Higher Pellet Recovery

Abstract

The Pressurized Heavy Water Reactor uses fuel in the form of natural UO₂ pellets, produced by powder metallurgy route from sinterable grade UO₂ powder. Ex-AU route is widely accepted process for production of highly sinterable grade UO₂ powder. The characterization of UO₂ powder is always paramount for final pellet recovery. Sinterability of UO₂ powder largely depends on precipitation and subsequent heat operation namely calcination and reduction. Ammonia flow rates during AU precipitation and temperature of calcination and reduction are critical to obtain desired UO₂ powder characteristics for achieving high sinterability during pellet fabrication. The present paper discusses the effect of critical parameters of precipitation, calcinations and reduction on final product and successful optimization of process parameters resulting in increase of production rate by 50%.