Environmental radioactivity proficiency tests: results evaluation of gamma radiation measurements in a case of emergency and continuously activities

Abstract

A valuable tool for external quality control that provides opportunity to improve analytical skills and techniques in the field of radioactivity measurements is participation in proficiency tests (PTs). In this work obtained results from the gamma spectrometry intercomparison for 15 laboratories conducted in May 1986 immediately after the Chernobyl accident for the lucerne sample contaminated with fission products: 140 Ba, 141 Ce, 144 Ce, 134 Cs, 137 Cs, 131 I, 103 Ru, 106 Ru, 95 Zr, are evaluated following the recommendations of the international standard ISO 13528:2005. Environmental radioactivity proficiency tests organized by International Atomic Energy Agency (IAEA) are designed to identify analytical problems, to help members states to maintain their accreditation and to provide knowledge and technology transfer in this area. The Analytical Laboratories for the Measurement of Environmental Radioactivity (ALMERA) is a world-wide network of analytical laboratories capable to analyzed radioactivity contents, coordinated by IAEA. Institute for the Application of Nuclear Energy (INEP), University of Belgrade, is an official member since 2013. Annual PTs are organized by ALMERA for the network laboratories using sets of different samples. Based on the PT proposition each result should pass accuracy and precision test to be awarded the status ‘Accepted’, otherwise it lies on the status ‘Warning’ or ‘Not Accepted’. INEP was participated in three worldwide open (in 2006, 2007 and 2011) and six (in a period 2012–2016) PTs organized by IAEA and ALMERA. Radionuclide activity concentrations in different environmental matrices were measured using gamma-ray spectrometer with high purity germanium (HPGe) detector. In IAEA worldwide open PTs among 61 results, 74 % were ‘Accepted’ and 26 % were ‘Not Accepted’. In ALMERA network PTs among 70 results, 84.3 % were ‘Accepted’, 4.3 % were ‘Warning’, 11.4 % were ‘Not Accepted’. PT exercises are the best way to identify gaps and problems areas where further development is needed.