Preludium NCN Katarzyna Mulewska

MSc. Eng, Katarzyna Mulewska

MSc. Eng, Katarzyna Mulewska is a laureate of PRELUDIUM 22 grant form NCN, tilted The impact of self–ion irradiation and temperature on the mechanical properties of ferritic-martensitic steels.

Nuclear reactor structural components are exposed to adverse operating conditions, including high temperature, high pressure, ionizing radiation, and interaction with aggressive cooling media that causes corrosion. Complex stress fields negatively impact these materials, leading to rapid wear. Therefore, understanding the processes in structural materials is imperative to guarantee the safe operation of the new generation of nuclear reactors. The austenitic steels currently in use fall short of meeting the new requirements due to poor radiation resistance and limited high-temperature mechanical properties. Hence, it is crucial to develop and select new materials, conducting comprehensive studies on changes in their properties under the mentioned operating conditions to bring Gen. IV nuclear reactor technologies to life.

New material was developed due to the combined efforts of scientists form the UE. Eurofer97, is a ferritic-martensitic steel with reduced activation, containing 9% chromium. High activation alloying elements (Mo, Nb, Co) have been replaced by low-activation elements (Ta, W, V).  Implementing new material solutions requires a series of systematic tests to ensure the material retains its structural integrity throughout its service life. Despite years of research, many unknowns are still associated with the Eurofer97 alloy.

Therefore, the project aims to study and understand the critical properties of ferritic-martensitic steels for nuclear applications, such as resistance to temperature or radiation damage. To better understand the effects of individual factors, such as alloying additives and temperature, on material properties, we will conduct tests on three model materials (Fe, Fe-9%Cr, Fe-9%Cr-NiSiP) and a commercial Eurofer97 steel, gradually increasing the microstructural complexity of the system. This procedure will help isolate the phenomena occurring in the material during the accumulation of radiation defects and temperature, allowing a better understanding of the relationship between microstructure and mechanical properties. The expected outcome of the project's research will be a better understanding of the behavior of F/M steels subjected to a nuclear reactor environment, including clarification of the effect of segregation into and out of grain boundaries and the localization of Cr in the vicinity of dislocations, leading to the hardening of the material.