Determination of 93Zr, 237Np and Th radionuclides in radioactive waste and mineral samples: extension of the method for determination of actinides

Abstract

A novel method has been developed for the simultaneous determination of difficult-to-measure (DTM) nuclides 93Zr, 237Np, 232Th, 230Th and 228Th using a DGA resin® (containing N,N,N′,N′-tetra-n-octyl-diglycolamide) column for simultaneous separation of Zr and actinides followed by purification of Zr, Np and Th on a TEVA resin® (containing Aliquat 336) column. Samples are destroyed by fusion with sodium hydroxide or by acid destruction using HNO3, HCl and HF. Pre-concentration procedure tailored to the extraction chromatography is based on co-precipitation of Zr and actinides and removal of alumina, silica, iron and calcium. The concentrations of 93Zr, 237Np and Th nuclides are determined by ICP-MS and α spectrometry, respectively. High chemical recoveries (≥ 73%) and separation factors were obtained for Zr, Np and Th both in evaporation concentrates of an NPP and various samples of mineral origin such as soil and concrete. The procedure can be easily combined with the simultaneous separation of other actinides (Pu, Am, U) using the same DGA column that has been described in our previous papers (Cassette et al. in Appl Radiat Isot 68:122–130, 2010 and Groska et al. in J Radioanal Nucl Chem 309(3):1145–1158, 2016).