Ceria-thoria pellet manufacturing in preparation for plutonia-thoria LWR fuel production

• Published in: Journal of nuclear materials 2016-10, Vol.479, p.184-188
• Main Authors: Drera, Saleem S., Björk, Klara Insulander, Sobieska, Matylda
• Format: Article
• Language: English
• Subjects: Halden; LWR fuel; Th-MOX; Thor energy; Thoria; Thorium
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2016.07.014

Thorium dioxide (thoria) has potential to assist in niche roles as fuel for light water reactors (LWRs). One such application for thoria is its use as the fertile component to burn plutonium in a mixed oxide fuel (MOX). Thor Energy and an international consortium are currently irradiating plutonia-thoria (Th-MOX) fuel in an effort to produce data for its licensing basis. During fuel-manufacturing research and development (R&D), surrogate materials were utilized to highlight procedures and build experience. Cerium dioxide (ceria) provides a good surrogate platform to replicate the chemical nature of plutonium dioxide. The project’s fuel manufacturing R&D focused on powder metallurgical techniques to ensure manufacturability with the current commercial MOX fuel production infrastructure. The following paper highlights basics of the ceria-thoria fuel production including powder milling, pellet pressing and pellet sintering. Green pellets and sintered pellets were manufactured with average densities of 67.0% and 95.5% that of theoretical density respectively. •High quality CeTh fuel production can be accomplished by utilizing powder metallurgical procedures.•Powder morphology is key to obtaining high density fuels.•Optimal pellet pressing is obtained when 3.5–4 tons of force is applied by the pellet press for powder compaction.•Pellet sintering is accomplished effectively in an Air oxidizing atmosphere.•Based on this surrogate work, expected (Th,Pu)O2 fuel density is 95.5% of theoretical density.