No abstract

Uranium determination by delayed neutron activation analysis is carried out by comparing the delayed neutron counts of a test sample to those of a uranium standard irradiated under identical conditions. Inaccurate results are obtained at high uranium concentrations (greater than approximately 0.05 mg 235 U), due to the deterioration of the linear relationship between delayed neutron counts and uranium content, and also when the sample matrix contains other elements that are neutron enhancers or absorbers, for example rare earth elements. In this paper, a correction method has been developed for the accurate analysis of samples with high uranium content (e.g. uranium peroxide). A second correction method, based on the thermal neutron self-shielding calculation developed by Chilian et al., has been applied to DNAA for the first time to correct for neutron absorption interferences in uranium analysis of rare earth-containing samples.