Copper and Phosphorus Effect on Residual Embrittlement of Irradiated Model Alloys and RPV Steels after Annealing

The transition temperature shift recovery efficiency after annealing (475оС, 100 hours) in dependence of copper and phosphorus contents has been studied on irradiated reactor pressure vessel (RPV) materials. A set of model alloys with low nickel content, lower than 0.2 mass%, were used for the scope of the study. Copper and phosphorus contents were varying in a wide range; 0.05÷0.99 mass% and 0.002÷0.039 mass% respectively. Recovery efficiency has been estimated by the value of residual embrittlement after annealing ( ). A comparison of the results obtained on model alloys with data for VVER-440 RPV materials has been carried out as well. The comparative analysis has confirmed the conclusion about independence on phosphorus content while it has shown that the effect of copper on is not significant for the typical VVER-440 RPV materials with typical range of contents between 0.10 and 0.24 mass %. For model alloys with wider range of copper content, copper is mainly controlling the .JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen