Evaluation Of Mechanical Properties Of The Reactor Pressure Vessel Materials Changes By Small Punch Test Application

The reactor pressure vessel (RPV) is the most important component of nuclear power plants. RPV steel near the reactor core is subject of irradiation degradation due to the fast neutron flux. Irradiation processes are rather complex but after all the damage of the steel crystal lattice lead to the changes of RPV mechanical properties as well as the shift of the transition temperature to higher values.Hence, monitoring of the RPV material irradiation changes must be proved during the all nuclear power plant (NPP) operation.The new surveillance specimen programs (SSP) at all Slovak NPPs reactors included, among the standard mechanical tests, also new types of evaluation mechanical properties due to method Small Punch Test (SPT).