Master Curve Evaluation of Irradiated Russian VVER Type Reactor Pressure Vessel Steels

Results of a joint German/Russian irradiation programme 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, T0, were evaluated according to the Master Curve (MC) concept using the
multi temperature method. Neutron irradiation induced ductile-to-brittle transition temper ature (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 behaviour of tested RPV steels are evaluated. Different heats of the same VVER-RPV steel exhibit different neutron induced embrittlement and annealing behaviour. The determined CVN transition temperatures correlates to the T0 temperatures evaluated by the MC concept.