Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Mixed nitride fuels fabrication in conventional oxide line

Bernard, H.; Bardelle, P.; Warin, D. (CEA Centre d'Etudes Nucleaires de Cadarache, 13 - Saint-Paul-lez-Durance (France))

Abstract

UPuN is a strong candidate fuel for advanced liquid metal cooled fast breeder reactor. So far, the main drawback is linked to the difficult and expensive preparation route compared to that of conventional MO2 fuels. This paper demonstrates that this difficulty has been overcorned : mixed mononitride pellets, with characteristics suitable for an irradiation testing in the PHENIX fast breeder reactor, have been obtained in a classical MO2 production facility without any significant modification of the set-up. The synthesis of MN involves the carbothermic reduction of the oxides. The reacted gas, namely CO, are continuously checked by an infra-red detector or a chromatographic gas analyser which allows the sharp control of the chemical conversion MO2 - MB. For consolidation, the granulation step is not necessary ; the cold pressing and the oxide type sintering have been adopted. For the pellets to be irradiated in the NIMPHE 1 experiment, values are in the range 0.23-0.07 wt % oxygen and 0.08 - 0.009 wt % carbon. Sintered densities are in the range 81-84 % T.D., with pellets diameter between 5.37 and 5.45 mm, which fits the requirements of radial gap and smear density. Extended analytical procedures including X-ray analysis, oxygen determination by the inert gas fusion method and carbon titration by the combustion technique, have finally demonstrated the suitability of the fa-bricated pellets for a first irradiation test of seven CEA UPuN pins, together with four similar EITE pins, now under way in the PHENIX reactor.

view the full text of this article (9 pages, format: PDF, size= 323kB)

key words: chemical preparation; fabrication; fuel pellets; lmfbr type reactors; performance testing; plutonium nitrides; uranium nitrides
Reference:
Technical committee meeting on advanced fuel for fast breeder reactors: Fabrication and properties and their optimization. Vienna (Austria). 3-5 Nov 1987
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--466, pp:42-50