Determination of americium and plutonium in contaminated soil samples

For the sequential determination of Pu and Am, soil samples were leached with 7.2 M HNO3 and plutonium was separated by anion exchange from HNO3 media. Americium was coprecipitated with calcium oxalate from the HNO3 wash solutions after Pu separation. For final purification of Am, anion exchange on Dowex 1X4 from 4 M NH4SCN was used. The influence of the various HCl concentrations in the 4 M NH4SCN feed solution starting the anion exchange process for Am has been investigated, following elution curves and determining distribution coefficients in column and batch experiments respectively. The resulting procedure has been proved in an intercomparison run and applied to soil samples from the Mururoa Atoll and Palomares. Spike recoveries for Am of about 70-80%, and in unfavorable cases of 30-40%, have been obtained.