Effects of Low Energy Beta Emissions on the Measurement Technique and Exposition Available to Purchase

We examined the suitability of taking smear tests (DIN ISO 7503.1) to evaluate surface activity. Special respect was given to mixtures of nuclides typical for the nuclear industry. We analysed the nuclides of samples of different fuel pools to evaluate the smear test measurement technique. Special calculations were carried out to examine the amount of nuclides that are difficult to measure due to their low maximum decay energy of less then 0.15 MeV (e. g. ⁵⁵Fe, ⁶³Ni). The response characteristic, detection sensitivity and the influence of the nuclide used for calibration were examined in detail on the basis of the nuclide vectors of fuel pool samples. We learned that especially the isotope standard used for calibration has a major influence for the suitability of the measurements. Calculation of the amount of these nuclides in relation to the effective dose (inhalation, ingestion) and the skin dose showed that they contribute little to the complete exposition.