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Preparation of bulk‐nanostructured UO 2 pellets using high‐pressure spark plasma sintering for LWR fuel safety assessment
Author(s) -
Tyrpekl Vaclav,
Cologna Marco,
Vigier JeanFrancois,
Cambriani Andrea,
De Weerd Wim,
Somers Joseph
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14647
Subject(s) - spark plasma sintering , pellets , materials science , nanocrystalline material , pellet , compaction , sintering , grain size , high pressure , grain growth , chemical engineering , metallurgy , composite material , nanotechnology , engineering physics , engineering
Nuclear fuel undergoes a significant restructuration during its lifetime in the nuclear reactor. Especially at the rim of the pellet, large UO 2 grains disintegrate into a nanosized material. In this paper, we focus on the preparation of bulk UO 2 with grain sizes below 100 nm to investigate the physico‐chemical properties of this so‐called “high burn up structure” ( HBS ). Preparation of bulk nanocrystalline materials is a challenge that can be overcome using the high‐pressure spark plasma sintering ( HP SPS ) technique. In‐house developed HP SPS with 500 MPa applied pressure was used for compaction of 11 nm UO 2 powder obtained by oxalate conversion. The procedure yielded dense (>90%) compacts with grain size as low as 34 nm for samples sintered at 800°C.