Study on Configuration of Nuclei for MnNi-Enriched Precipitation in Model Reactor Pressure Vessel Steels

It has been justified that Mn Ni-enriched precipitation（MNP） is an important contribution to the embrittlement of low-alloyed reactor pressure vessel（RPV） steels（like A508 III steel） when irradiated to high dose in like 60 to 80 years. In this paper the Molecular Statics method was used to calculate the binding energy and formation energy among solutes and defects, so as to find out the possible nuclei of MNP with the lowest energy, which might be classified into two kinds of complexes, one composed by Cu and several（≥3） vacancies and the other mixed FeMn＜110＞ dumbbell with Mn, Ni or Cu atoms trapped.