Evaluation of alkali fusion and acid leaching methods for the determination of insoluble plutonium and americium in fecal samples

Abstract

Monitoring of radiation workers of fuel reprocessing plant and fuel fabrication facility for internal contamination is carried out by analyzing their urine and fecal samples. Assessment of intake is made from these results using standard biokinetic and dosimetric models. In the analysis of fecal samples, there is a need for improvement in the pretreatment technique for complete dissolution of the sample. Conventional alkali fusion method has yielded recovery of plutonium in the range of 12-60% with a mean of 36%. Newly adopted acid leaching followed by hydrogen fluoride treatment method achieved recovery in the range of 43 to 90% with a mean of 70%. Conventionally, the separation of "Pu" and "Am" was carried out at Bioassay Lab., Tarapur by alkali fusion followed by the anion exchange separation for Pu and cation exchange separation for Am. This paper deals with an alternative method in which initially the entire ash of the sample spiked with ²³⁶ Pu tracer (3-11 mBq) and ²⁴³ Am tracer (2.8-14.5 mBq) was acid leached and Pu was separated by anion exchange method and Am by using TRU resin.