Control of Urania Crystallite Size by HMTA-Urea Reactions in the Internal Gelation Process for Preparing (U, Pu)O2Fuel Kernels

Collins, J.L.

Oak Ridge National Laboratory

关键词: Urotropin;    Ornl;    Gelation;    Kernels;    Crystal Growth;   

DOI  :  10.2172/885943
RP-ID  :  ORNL/TM-2005/10
RP-ID  :  DE-AC05-00OR22725
RP-ID  :  885943

美国|英语

来源: UNT Digital Library

【 摘 要 】

In the development of (U,Pu)O{sub 2} kernels by the internal gelation process for the Direct Press Spheroidized process at Oak Ridge National Laboratory, a novel crystal growth step was discovered that made it possible to prepare calcined porous kernels that could be used as direct-press feed for Fast Breeder Reactor pellet fabrication. High-quality pellets were prepared that were near theoretical density and that (upon examination) revealed no evidence of sphere remnants. The controlled crystal growth step involved using hexamethylenetetramine (HMTA)-urea stock solutions that were boiled for 60 min or less. Before this discovery, all the other crystal growth steps (when utilized) could reduce the tap density to only {approx}1.3 g/cm{sup 3}, which was not sufficiently low for use in ideal pellet pressing. The use of the boiled HMTA-urea solution allowed the tap density to be lowered to 0.93 g/cm{sup 3}, with the ideal density being about 1.0 g/cm{sup 3}. This report describes the development of this technology and its scaleup.