A new approach of radiation damage data reduction is presented. The approach, called Constant Chemistry Analysis (CCA), is based on the systematic analysis of radiation damage observed on groups of steels having practically the same chemistry, in terms of copper and nickel content, individually considered.
For each group, a chemistry factor (CF) and exponent describing the reference transition temperature shift (ΔRTNDT) trend versus fluence has been inferred.
Finally, a prediction formula for the overall trend is derived bestfitting the chemistry factors and the exponents previously determined. This particular approach emphasizes the role played by copper and nickel on the build-up of radiation damage.
The major finding is that saturation may take place in steels with very high copper/nickel ratio after great damage in the early stage (low fluence).
Furthermore, nickel seems to not contribute in an adverse manner to the radiation damage but it rather helps to reduce the ΔRTNDT up to a content of about 1.0% over which it starts to develop an independent negative effect.
The steels considered in the analysis are A533 and A508 irradiated in test reactors in the United States, Germany, Japan, France, and Sweden with a copper and nickel content spanning from 0.02% to 0.22% and from 0.5% to 1.4%, respectively. The fluence (E > 1 MeV) was ranging from 1 × 1019 n/cm2 to 9 × 1019 n/cm2.