DETERMINATION OF THE CM-243 CM-244 RATIO ALPHA-SPECTROMETRY AND SPECTRAL DECONVOLUTION IN ENVIRONMENTAL-SAMPLES EXPOSED TO DISCHARGES FROM THE NUCLEAR-FUEL CYCLE/

The presence of curium nuclides in irradiated nuclear fuel is well kno wn, as is their occurrence in environmental materials exposed to liqui d waste discharges from reprocessing plants and to fallout following t he Chernobyl accident. Knowledge of the Cm-242/Cm-244 and Cm-243/Cm-24 4 atom ratios can be a useful tool for characterizing a source-term an d assessing the burn-up history of nuclear fuel. Here, a practical tec hnique, based on high-resolution a spectrometry and spectral deconvolu tion, is described by which the Cm-243,Cm-244 multiplet can be resolve d at the low activities typical of most environmental samples. The res ulting Cm-243/Cm-244 ratio is then used to correct for any interferenc e by Cm-243 in the Cm-242 window. The technique has been applied to th e determination of the Cm-243/Cm-244 ratio in samples of seabed sedime nt collected near the Sellafield outfall, riverine sediment sampled do wnstream of the Mayak reprocessing plant and soil and lichen from with in the Chernobyl exclusion zone. Near Sellafield, the Cm-243/Cm-244 ra tio was found to be <2%, while near Mayak and Chernobyl it was conside rably higher, being similar to 6-8%. (C) 1998 Elsevier Science Ltd. Al l rights reserved.