Preparation of reference material for uranium and plutonium measurements using cellulose compound as a stabilizer

Isotope dilution mass spectrometry, considered the most reliable analytical technique for input accountancy measurements of uranium and plutonium in spent fuel reprocessing plants, requires a well-characterized uranium/plutonium spike. Solid spikes containing 235U and 239Pu have been successfully utilized in safeguards inspections and in accountability analysis. They contain relatively large amounts of uranium and plutonium isotopically different to the uranium and plutonium of the sample, and are usually in the dried nitrate form. However, it is difficult to maintain and guarantee the integrity of the spike over long periods as they are in the dried nitrate form that can flake off the glass ampoule surface. Organic coatings were investigated using cellulose acetate butyrate as a stabilizer. The cellulose acetate butyrate had good characteristics, maintaining a thin film for a long time. (author)