LASER-ABLATION INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY FOR THE DETERMINATION OF LANTHANIDES AND URANIUM IN FUEL RECONDITIONING MATERIALS - PROBLEMS, SOLUTIONS AND IMPLICATIONS

The successful determination of uranium, lanthanum, cerium, neodymium and yttrium by LA-ICP-AES is reported, LA was performed using a Q-swit ched Nd:YAG laser operating at 1064, 532 or 355 nm, Ablation at 355 nm was shown to offer optimum performance, The sample matrix consisted o f a mixture of lithium and potassium chlorides which, when molten, for m the electrolyte for an electro-refining process for the treatment of spent nuclear fuels, Analytical recoveries in the range 96-103% were obtained with a relative standard deviation of 1-3%, i.e., U = 100%, L a = 100%, Ce = 96%, Nd = 97% and Y = 103%, The detection limit for ura nium was 25 mu g g(-1) using the optimum LA conditions, The use of sol id standards closely matching the sample material was found to be esse ntial if accurate analyses were to be obtained, Calibration using uran ium compounds other than the specific compound found in the sample was unsuccessful, For results of the highest quality, single phase materi als were produced to allow for accurate internal standardization. Spec tral interferences were minimized by the use of high resolution spectr ometry, The reliability of the analyses was improved by the introducti on of additional aerosol processing in the form of a Scott-type spray chamber between the ablation cell and the ICP torch.