RAPID-DETERMINATION OF TRANSURANIUM NUCLIDES IN THE PRIMARY COOLANT OF A NUCLEAR-POWER-PLANT BY USING NUCLEAR TRACK MICRO FILTERS AND INVESTIGATION OF ALPHA-EMITTING PARTICLES ON THE LOADED FILTERS BY ALPHA-AUTORADIOGRAPHY

Nuclear Track Micro Filters (NTMF) have been applied to analyze the pr imary coolant of a nuclear power plant for its content of transuranium elements and solid contaminants. The obtained sample, i.e. the loaded filter, has been investigated for its alpha- and gamma-activity, as w ell as for studies of solid contaminants of the primary coolant using SEM (scanning electron microscope) attached with EDXA (energy dispersi ve X-ray analysis). The comparison of the results of the chemical anal ysis of the filtrate and the results of the filtration method shows, t hat the NTMF made of Kapton are capable to retain (90 +/- 10) % of the total transuranium alpha-activity. However, the actual content of suc h alpha-activities varied considerable from sample to sample. In order to get an explanation of this variation in samples taken at the same time from the reactor cooling circuit, it was tried to find out, wheth er the transuranium elements are evenly distributed in the coolant or occure point-like (''hot spots''). For this purpose alpha-autoradiogra phy using CR-39 exposed to the loaded filters was employed. The observ ed, uneven distribution of tracks on the surface of the CR-39 indicate s, that the transuranium elements are adsorbed at the surface of small solid particles, possibly consisting of zirconium and other elements of the fuel elements and the structural material of the nuclear reacto r cooling circuit. An other possibility could be the occurence of the transuranium elements in large agglomerates or ''clusters'' in the pri mary coolant.