Trace metal assay of plutonium and uranium bearing nuclear fuel materials by atomic spectroscopic techniques

The determination of impurities in plutonium/uranium at various stages of the nuclear fuel cycle plays an important role in quality control and the achievement of chemical and metallurgical requirements. Because impurities such as Cd, B and certain rare earth elements (Gd and Sm) are strong neutron absorbers, their concentration in nuclear fuel has to be maintained below certain limits. Increased concentration of other impurities may alter the metallurgical characteristics of the fuels, for instance strongly affecting the transition temperature between the different uranium/plutonium metal phases. AES methods based on d.c. arc-carrier distillation approach by far have served as the main workhorse in analytical spectroscopy of nuclear materials as it offers simultaneous multi-element determination, least handling of the sample and requires small sample size. The various methodologies developed in our laboratory for determination of trace metallic constituents in nuclear fuel materials such as PuO2, (U,Pu)O2, and ThO2 are discussed