EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

MYRRHA (short for Multi-purpose hYbrid Research Reactor for High-tech Applications) is a new accelerator driven system, currently under development at SCK CEN in Mol, Belgium. This nuclear system will use liquid Lead Bismuth-Eutectic (LBE) as spallation source for fast neutron production and as coolant. One of the main challenges of building MYRRHA is to find a material which can withstand the heavy liquid metal environment. Currently, the main candidate materials for the structural parts of this reactor are austenitic stainless steels similar to AISI 316L. Two different plates of 316L-type material (35 mm and 72 mm) have been welded (by Gas Tungsten Arc Welding and Submerged Arc Welding resp.) and are investigated in this study. In order to test the suitability of this material (including its welds and heat-affected zones) in contact with the liquid metal environment, a variety of experiments have to be performed to investigate the potential influences on mechanical properties. LBE is opaque and electrically conductive. In combination with the high temperatures of up to 500 °C, standard equipment such as extensometers and clip gages cannot be used and hence no live measurement of strain or crack length can be observed. Next to the difficulties with the environment, the availability of welded material for testing is limited, which results in relatively small test specimens. Nevertheless, by combining reference testing with modern measurement methods such as digital image correlation (DIC) and finite element modelling (FEM), it is possible to overcome these challenges. In the current work we show the results of mechanical tests of the base, weld and cross weld material and how to get additional information from the DIC method that can help with the interpretation of the tests performed in liquid metal environment.