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Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique

Abstract

High density fuels, either in uranium monocarbide or in U-UC cermets have been prepared on laboratory-scale, by hot pressing of mixtures of uranium powder and graphite in suitable proportions. Uranium powder is prepared by calcium reduction of UO{sub 2} followed by an acetic leaching at low temperature. An adequate protection-treatment permits the manipulation of the powder in the open air. Uranium and Graphite powders are intimately mixed and then hot pressed in a double effect graphite die at a temperature of 900-1000 deg. C under a charge of 200 kg/cm{sup 2} during 3 hours. A special design of the die avoids the breaking of the graphite during the sintering. In this way, samples are prepared, the characteristics of which are: 1) {+-} 5 pour cent of homogeneity for a ratio height/diameter = 2. 2) almost theoretical density (98 pour cent) 3) low concentration of unreacted carbon (heat treatment of stoichiometric monocarbide can be useful for completion of reaction) 4) the micrographic examination shows: - a network of monocarbide surrounding uranium in the case of low concentration cermets (<2,5 per cent C) - two networks intimately mixed for high concentration cermets (<2,5 per cent C) - a fine grain structure for  More>>
Authors:
Dubuisson, J; Houyvet, A; Le Boulbin, E; Lucas, R; Moranville, C [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1958
Product Type:
Technical Report
Report Number:
CEA-R-991
Resource Relation:
Other Information: 3 refs
Subject:
36 MATERIALS SCIENCE; BENCH-SCALE EXPERIMENTS; BULK DENSITY; CERMETS; CORROSION RESISTANCE; DIES; FUEL ELEMENTS; FUEL-CLADDING INTERACTIONS; GRAIN ORIENTATION; GRAIN SIZE; GRAPHITE; HOT PRESSING; METALLOGRAPHY; POLISHING; POWDERS; SINTERED MATERIALS; SINTERING; THERMAL CYCLING; URANIUM; URANIUM CARBIDES; VICKERS HARDNESS; X-RAY DIFFRACTION
OSTI ID:
20901040
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R0991063263
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
32 pages
Announcement Date:
Aug 28, 2007

Citation Formats

Dubuisson, J, Houyvet, A, Le Boulbin, E, Lucas, R, and Moranville, C. Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique. France: N. p., 1958. Web.
Dubuisson, J, Houyvet, A, Le Boulbin, E, Lucas, R, & Moranville, C. Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique. France.
Dubuisson, J, Houyvet, A, Le Boulbin, E, Lucas, R, and Moranville, C. 1958. "Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique." France.
@misc{etde_20901040,
title = {Hot pressing of U-UC cermets and stoichiometric uranium monocarbide; Preparation par frittage sous charge de cermets U-UC et de monocarbure stoechiometrique}
author = {Dubuisson, J, Houyvet, A, Le Boulbin, E, Lucas, R, and Moranville, C}
abstractNote = {High density fuels, either in uranium monocarbide or in U-UC cermets have been prepared on laboratory-scale, by hot pressing of mixtures of uranium powder and graphite in suitable proportions. Uranium powder is prepared by calcium reduction of UO{sub 2} followed by an acetic leaching at low temperature. An adequate protection-treatment permits the manipulation of the powder in the open air. Uranium and Graphite powders are intimately mixed and then hot pressed in a double effect graphite die at a temperature of 900-1000 deg. C under a charge of 200 kg/cm{sup 2} during 3 hours. A special design of the die avoids the breaking of the graphite during the sintering. In this way, samples are prepared, the characteristics of which are: 1) {+-} 5 pour cent of homogeneity for a ratio height/diameter = 2. 2) almost theoretical density (98 pour cent) 3) low concentration of unreacted carbon (heat treatment of stoichiometric monocarbide can be useful for completion of reaction) 4) the micrographic examination shows: - a network of monocarbide surrounding uranium in the case of low concentration cermets (<2,5 per cent C) - two networks intimately mixed for high concentration cermets (<2,5 per cent C) - a fine grain structure for the monocarbide (10 u). 5) In every case, the X rays examinations show a fine grain structure without any orientation, and no UC{sub 2}. Some indications are given on the physical (thermal cycling, conductibility) and chemical properties (corrosion, reaction with cladding materials). (author)Fren. [French] Une methode de preparation de combustibles de haute densite, soit en monocarbure d'uranium, soit en cermets U-UC, a ete mise au point au laboratoire. Il s'agit du frittage sous charge de melanges de poudres d'uranium et de graphite en proportion convenable. La poudre d'uranium est elaboree par calciothermie de l'oxyde UO{sub 2} suivie d'un lavage acetique a basse temperature. Un traitement de protection adequat pe sa manipulation a l'air. Les poudres d'uranium et de graphite sont intimement melangees, puis frittees dans une matrice a double effet en graphite a une temperature de 900-1000 deg. C sous une charge de 200 kg/cm{sup 2} pendant 3 heures. Un conditionnement particulier de la matrice permet d'eviter la rupture durant le frittage. On obtient ainsi des elements dont les caracteristiques sont les suivantes: 1) Homogenes a {+-} 5 pour cent pres pour un rapport diametre hauteur/diametre = 2. 2) Densite voisine de la densite theorique (98 pour cent). 3) Faible teneur en carbone non reagi (un traitement thermique ulterieur est parfois necessaire dans le cas du monocarbure stoechiometrique pour completer la reaction). 4) La micrographie montre: - pour les cermets a faible teneur en UC (<2,5 pour cent C) un reseau de carbure entourant les billes d'uranium. - pour les cermets a forte teneur en UC (<2,5 pour cent C) deux reseaux imbriques d'UC et uranium. - pour le monocarbure, une structure a grains fins (10 microns). 5) Dans tous les cas, les rayons X revelent une structure a grains fins sans orientation, et ne decelent pas d'UC{sub 2}. Quelques indications sont donnees sur les proprietes physiques (fatigue thermique, conductibilite) et chimiques (corrosion, reaction avec les metaux de gaine). (auteur)}
place = {France}
year = {1958}
month = {Jul}
}