EPR Round Robin Test with sensitised austenitic steels Part 1: Evaluation of results according to the JIS method

During a workshop organised by Siemens Nuclear Power GmbH (SNP) and GfKORR several experts and users of the EPR method came together to exchange their experiences and to launch a Round Robin test. The goal of the Round Robin test was to compare the results of the participating labs and determine the ir deviation. In addition an approach for a new ISO standard should be foun d and the differences within the standardised and the individual methods sh ould be shown. Due to the complicated evaluation, especially of the lab-spe cific methods, only the results according to the JIS standard will be prese nted at this time. The ranking of the degree of sensitisation was identified correctly by all participants, but regarding one specific degree of sensitisation the result s are spreading within a large scatter band. The results of the round robin test show that: - more precise specifications are necessary to carry out the test - it must be determined which parameters have to be documented. Especially differences from the standards should be recorded. The results also demonstrate the necessity of a metallographic documentatio n of the tested area in order to classify and interpret the reactivation ra tio. The results of this round robin test are considered as an important ba sis to establish a new test specification.