DEscription of the extended LIfetime and its influence on the SAfety operation and construction materials performance – Long Term Operation with no compromises in the safety

The aim of the project is to determine the most affected and threatened components from the point of view of the long-term operation (LTO) and describe the effect of the LTO on the material properties as well as develop a simulation tool able to predict the non-acceptable state of the material. The project is specifically focused on the Water-Water Energetic Reactor (VVER), nevertheless, the approach is to maintain the easy transferability to other light water reactor technologies, as well. The outputs of the project will lead to the increase of operational safety at the extended lifetime due to the in-time prediction of the potential failure. The basic approach of the project is to combine the development of the simulation tools, experimental work (material analyses), in-service and/or non-destructive inspection techniques to develop the effective “early warning” tool for the assessment of the system integrity for the LTO of the current LWR with a specific focus on the VVER technology. The project's aim specifically focuses on the thermal aging and swelling of the loaded constructional materials. One of the most affected components from the LTO´s point of view are the heat exchanging tubes of steam generators (thermal ageing) and reactor internals (swelling). The experimental material was screened and selected with the main criteria: to support and validate the proposed methods in the most accurate way, and to be “on stock” and available at the expected start of the project, the latest. The experiments are planned to be performed at the available material with clear and well-described operational history as well as the material from the original batch in the “as-received” state to gain the most relevant and valuable information with high impact to the community.