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We discuss irradiation tests performed at the Budapest research reactor operating with 10 MW using a new irradiation rig. Some examples of the use of the irradiation rigs are presented: results of reactor pressure vessel cladding, 9% Cr steels (Euroferr), application of Master Curve to irradiated reactor pressure vessel steels, as well as irradiation tests of Ti-alloys and tungsten. [ABSTRACT FROM AUTHOR]

Reactor internals are subjected to three principal operation effects: neutron and gamma irradiation, static and dynamic mechanical stresses and coolant chemistry. In this study, we investigate the effect of these mechanisms on WWER 440 reactor vessel internals and present lifetime analysis, in order to extend the operational lifetime of reactor vessel internals. [ABSTRACT FROM AUTHOR]

Mechanical properties of WWER-440 RPV weld joints have been studied with account of different states of the material: baseline (unirradiated), irradiated up to the average fast neutron fluence of $\backslash 6.5\; cdot\; 10^19$ n/$\backslash cm^2$, irradiated and eventually annealed, re-irradiated with the accumulated fast neutron fluence $\backslash 1.3\; cdot\; 10^20$ n/$\backslash cm^2$. Tensile, impact fracture, and fracture toughness tests were performed for each state of the material with the use of Charpy specimens (standard, reconstituted, and pre-cracked). [ABSTRACT FROM AUTHOR]

Radiation embrittlement and aging mechanisms for NPP reactor pressure vessels and vessel internals have been studied within NPP Plant Life Management activities for the evaluation, prediction, and monitoring of the critical components' service life. The main achievements of the SAFELIFE project, integrating various networks on PLIM issues, are given. Results of neutron embrittlement of model alloys are presented, and surveillance and research data on WWER reactor pressure vessel and other steels are analyzed. Projects for the development of destructive and non-destructive testing of irradiated materials are outlined. [ABSTRACT FROM AUTHOR]

EUROATOM research programs aimed at studying aging mechanisms and remedial procedures for structural materials of nuclear reactor components have been analyzed. Within this framework, projects are carried out focusing on the development of non-destructive techniques applied to thermal aging, neutron embrittlement monitoring, improved surveillance for WWER-440 reactors, dosimetry, and the use of various fracture mechanisms for NPP integrity assessment. Among major achievements are the ATHENA project activities on re-embrittlement model validation after annealing and the effect of chemical composition on the embrittlement rate in RPV steels. A brief description is given of the main results of current EUROATOM projects, as well as the goals of the next stage of research within the SAFELIFE network on the NPP Plant Life Management. [ABSTRACT FROM AUTHOR]