Speaker
Description
The Faculty of Nuclear Sciences and Physical Engineering CTU in Prague (FNSPE) has been providing periodic monitoring of the impact of the operation of the NPP Temelin on the environment since 2000 (including the zero state). Monitoring is conducted at 29 selected reference points within an area with radii of 2, 5, 10, and 20 km around the NPP. Samples of Schreiber's moss, forest humus, pine bark, mushrooms, and forest fruits are collected with an annual period. After drying, the samples are measured by laboratory gamma spectrometry and analyzed for the presence of Cs-137 and other artificial radionuclides. The movement of Cs-137 in the forest (uncultivated) soil profile was studied twice during the monitoring period on samples taken at 2 cm intervals in depth profiles. Laboratory measurements allowed the determination of the Cs-137 effective half-life. FNSPE contributes to the monitoring system of the CR with spectrometric measurements using in situ scintillation spectrometry, which take place over a two-year period. For processing the results of in situ spectrometric measurements (performed mainly by portable spectrometers Mirion/Canberra Osprey with NAIS-3×3™ detection probe and µNOMAD EG&G Ortec with NaI(Tl) 3×3" Bicron detector), a methodology for determining the effective surface activity of Cs-137 and concentrations of K, U, and Th in the surface layer of soil was developed. The presentation summarizes the results of applying this methodology to spectrometric measurements during the monitoring period and compares them with the results of comparative measurements performed by other spectrometric devices or other methodologies (in situ measurements with a portable spectrometer GT-40 and laboratory analysis of forest humus samples). The results were used to validate the developed methodology, the reproducibility of such measurements, and the impact of the geological background composition assessment.