ELIÁŠOVÁ Ivana UJV Řež, a. s.

Spoluautoři KOPŘIVA Radim, SIEGL Jan

The subject of this paper is the use of instrumented hardness test for determination of the mechanical properties of the long term operated components of nuclear power plant, which are difficult to replace. These include the reactor pressure vessel, reactor pressure vessel’s internals and the components of the primary circuit. The method is derived from technological processes which allow for a small amount of the studied material to be obtained directly from the component while preserving its structural integrity. The use of remote control operated test devices provides the option of the in-situ studies of the components during reactor outage. The base principle of instrumented hardness testing is multiple indentations by spherical indenters at the same test location on the surface of test sample with intermediate partial unloading. Testing is automated, rapid and localized, and allows determination of the true stress versus true plastic strain characteristic of metallic materials having matching tensile and comprehensive strength properties. Results obtained from instrumented hardness tests on NPP structural materials would be valuable contribution in enlargement of data base for component integrity assessment and safe operation assurance.