Note on an interlaboratory examination of mixed uranium-plutonium oxide fuel for qualification for reactor use

Experimental fuel for the United Kingdom fast reactor programme is fabricated and characterized on three sites, Windscale, Harwell and Aldermaston. The assessment of fuel behaviour relies partly on analytical data and it is important that there is good correlation between the results obtained from different laboratories. The assay of uranium, plutonium and isotopic abundance, oxygen-metal ratio and carbon content in mixed oxide are key areas. This note reports results obtained on an experimental batch of mixed oxides of enriched uranium and plutonium, by the analytical sections at AERE, Harwell, BNFL, Windscale and AWRE, Aldermaston. There was good agreement on assay of U, Pu and isotopes, although preliminary trials on the material indicated the possibility of discrepancies when assaying non-standard materials. A significant difference was noted between oxygen-metal ratio results obtained by the X-ray method and those obtained by thermochemical means. (author)