Intercomparison exercise on difficult to measure radionuclides in activated steel: statistical analysis of radioanalytical results and activation calculations

This paper reports the results obtained during an intercomparison exercise for the determination of difficult to measure radionuclides in activated reactor pressure vessel (RPV) steel samples. In total, eight laboratories participated analysing 14 C, 55 Fe and 63 Ni activity concentrations in RPV steel. In addition, some laboratories also analysed 60 Co activity concentrations. Corresponding activity concentrations were also determined using activation calculations. Robust statistical techniques were utilised for the analysis of the results according to ISO 13528 standard. The results showed good agreement for 55 Fe and 63 Ni results whereas 14 C results had significant differences. 60 Co results were in quite good agreement.