ADS Candidate Materials Compatibility with Liquid Metal in a Neutron Irradiation Environment
Author: Van den Bosch, J.
Subject: ADS Candidate Materials Compatibility with Liquid Metal in a Neutron Irradiation Environment
Promotor: Degrieck, J.
SCK CEN Mentor: Al-Mazouzi, A.
Lead bismuth eutectic is selected to be both coolant and spallation target material for the future experimental accelerator driven system (MYRRHA). This new concept of reactor type might be one of the possible solutions for the nuclear waste problem as it is conceived to be able to burn up high level radioactive waste and long lived actinides.
The ADS technology however requires special operating conditions. The materials need to withstand temperatures ranging between 200° and 550°C under high neutron flux and in contact with the liquid lead bismuth eutectic (LBE). This liquid metal contact does not only result in liquid metal corrosion but might also facilitate liquid metal embrittlement (LME).
Therefore, the first goal of this PhD thesis was to characterize possible liquid metal embrittlement of T91, 316L and their welds in contact with liquid lead bismuth eutectic. Furthermore, several experimental steels which contain an elevated concentration of silicon to increase their corrosion resistance in LBE were examined for possible liquid metal embrittlement as well.
The second part of this thesis deals with the conception, construction and the irradiation of a set-up where the reference materials as well as their welds and some specific alloys (Si-enriched steels) were in contact with LBE. The goal of this experiment, the first of its kind worldwide, was to study the separate and the combined effect of neutron irradiation and contact with liquid LBE. The issues related to the safety and the control of such experiment were tackled in a coordinated way between different departments and institutes inside and outside the Belgian nuclear research centre where this work has been performed. This first irradiation campaign made it clear that dealing with irradiated LBE is not an easy issue.
Due to licensing and safety regulations it was not possible up to now to further examine surface layers or fracture surfaces.