Master curve evaluation of irradiated Russian VVER type reactor pressure vessel steels

Results of a joint German/Russian irradiation program performed on the prototype pressurized water reactor VVER-2 of the Rheinsberg nuclear power plant (Germany) are summarized. The experiment comprises Charpy V-notch (CVN), precracked Charpy size (SENB) and compact tension (CT) specimens made of different heats of Russian VVER type reactor pressure vessel (RPV) base and weld metals. Reference temperatures, T-0, were evaluated according to the Master Curve (MC) concept using the multi temperature method. Neutron irradiation induced ductile-to-brittle transition temperature (DBTT) shifts determined on the basis of CVN and SENB tests are compared. On the base of the DBTT the neutron embrittlement sensitivity and the annealing behavior of tested RPV steels are evaluated. Different heats of the same VVER-RPV steel exhibit different neutron induced embrittlement and annealing behavior. The determined CVN transition temperatures correlates to the T-0 temperatures evaluated by the MC concept.