Proficiency test of radioactivity measurement of gamma-ray emitting radionuclides in Korea

The Korea Research Institute of Standards and Science (KRISS) has been conducting proficiency tests of the radioactivity measurement of gamma-ray emitting radionuclides for domestic institutes in Korea. The test scheme used the z & PRIME;-score with a robust analysis based on the International Standard Organization (ISO) 17043 and ISO 13528 standards for evaluating the measurement performance. The z & PRIME;-score employed a robust standard deviation by Algorithm-A in the ISO 13528 standard instead of using a traditional standard deviation of participant results. The proficiency test materials (PTMs) were prepared by spiking a diluted standard solution of radionuclides of interest into acidified water with 1 M HCl. Combinations of Cs-134, Cs-137, Co-57, Co-60, Y-88, Sn-113, and Cr-51 were used as PTMs. KRISS satisfies proficiency testing requirements, and the test is accredited by the Korea Laboratory Accreditation Scheme (KOLAS). KRISS has conducted proficiency tests annually since 2016, and more than 70 laboratories have tested over 650 test items so far. This study presents the results provided by the participants and the observed trends.