Speaker
Description
Authors (affiliation): 1.Wan-Tzu Hung (INER, Taiwan), 2. Wei-Han Chu (INER, Taiwan), 3.Ming-Chen Yuan (INER, Taiwan)
The Institute of Nuclear Energy Research (INER) is recognized by the Taiwan Accreditation Foundation (TAF)as the main organizer for low and intermediate activity level proficiency tests. The INER is requested to conduct this proficiency test at least every three years, therefore, this research reviewed the results of the summary reports from 2013 to 2021. The test items of the proficiency test are 7 in total according to the TAF test item category. These items include gamma nuclides analysis, tritium nuclides analysis, total beta nuclides analysis, strontium 90 analysis, mixed gamma nuclides analysis, mixed strontium 89/90 nuclides analysis and mixed iron 55/59 nuclides analysis. In 2021, in response to the difficult-to-measure nuclides that may be derived from the decommissioning of nuclear power plants, INER went for the first implementation of the project for mixed nuclides analysis projects which addded the items of Ni-63, Tc-99 and Am-241.Besides, it was not only the year for the most numerous nuclear species to be tested, but it also had the greatest number of testing items for this proficiency test within a decade.
Generally,the actual blank matrix is used and prepared for adding radioactive sources that can be traced back to the national ionizing radiation standard. Each participating laboratory could select the test samples for the analysis and comparison according to their own needs. The specific activity of each sample was about 0.5 kBq/g to 10 kBq/g. While the laboratory performing the blinded test, for each group of test categories, the analysis was to be repeated for 2 to 5 times.
Requirements for passing the test in accordinance with TAF criteria (TAF-CNLA-T10(3)) : (1) Ratio: The ratio between the measurement value of the proficiency test executing agency and its measurement standard uncertainty is called the resolution. Whether the test results are recognized relies on the activity of the radioactive species. The ratio of the laboratory's test value and the test value of the proficiency test executing agency, in accordance with the corresponding resolution, if the ratio falls within the limit value, the measurement ratio of the test laboratory is qualified; (2) ξ(zeta score): It is defined as subject to the ratio of the deviation between the test value of the test laboratory and the test value of the proficiency test executing agency and the combined standard uncertainty, if ξ<3,it then passed the zeta score evaluation; (3) The measurement standard uncertainty of the test value for the tested laboratory and the proficiency test executing agency should be less than 10%, it should be evaluated according to the methods described in ISO/IEC Guide 98-3. The participating laboratories will pass the proficiency test only if they meet all requirements above.
