WP3 – P1 Summary
MatISSE WP3 – Characterization of ceramic composites for GFRs and LFRs
Summary of periodic report 1.11.2013 – 30.04.2015
The general objective of WP3 is the characterization of ceramic composites for GFRs and LFRs. The activities were organised in four different sub tasks, as described in the following table. SiC/SiC composites are considered very promising candidates for GFR fuel cladding. In order to demonstrate this, full ceramic SiC/SiC and hybrid SiC/SiC with a tantalum liner clad sections are being fabricated (3.1) and assessed (3.2 and 3.3). Task 3.4 deals with a different kind of ceramic composites, MAX phase cermets, particularly promising for LFR pump impeller.
• Task 3.1: CEA, ENEA • SiC/SiC and sandwich tubes fabrication, quality assessments and supply
• Task 3.2: PSI, CEA, POLITO, UOXF, UNIMAN • Mechanical, leak tightness and thermal properties of SiC/SiC and sandwich clads and microstructure correlations
• Task 3.3: KIT, NNL,CVR, POLITO • Assessments about SiC/SiC and sandwich clad compatibility with impure flowing He coolant
• Task 3.4: SCK.CEN, KUL, CIEMAT, KIT, ENEA, KTH • Development of optimized MAX phase cermets for LFR pump impeller
SiC/SiC clad sections were produced by CEA, with length up to 190 mm and different external surface finishing. Quality inspection via non-destructive testing (NDT) had been performed before any further ageing or mechanical characterisation. Ultrasonic scanning and X-ray tomography proved to be the best NDTs for SiC/SiC clads, and that ultrasonic scanning may evidence not only macroscopic defects (delamination, large voids) but also to microscopic features quickly and easily.
The study has focused up to now on:
- Stress-strain behaviour of SiCf/SiC/sandwich clads under tensile and bi-axial loading (tensile test + torsion and tensile test + hoop stress) at room temperature.
- Leak tightness characterization of SiC/SiC/sandwich clads under hoop stress loading, up to 600°C (aiming at 1000°C)
- Feasibility evaluation of using high resolution X-ray tomography during mechanical tests with strain mapping by image correlation for damage characterization
- Thermal property characterization and modelling. Apparatus have been developed and adapted in order to measure the thermal conductivity of multi-layered and sandwich SiC/SiC cladding tubes at temperatures ranging from the ambient up to 1000°C. These data will serve as input data for modelling.
The study has included up to now:
- The identification of most suitable coolant reference chemistry (by literature review and discussion).
- Corrosion kinetics studies by thermo-gravimetric analysis.
- Activity on the development of an apparatus for corrosion kinetics studies in impure flowing He up to 900°C.
The study focused on processing and characterization of MAX phase-based cermets, and in particular on:
- Pre-selection of promising MAX phases, based on activation calculations using OrigenARP and neutron cross-sections.
- Microstructural characterization and mechanical testing of bulk, commercially-available MAX phases.
- Synthesis and characterization of MAX phases via a powder metallurgical route.
- Compatibility studies with liquid LBE.
- Assessment of the resistance of various metals to LBE attack aiming at MAX phase-based cermets.
- Material testing at high LBE flow velocities (employing CORELLA facility).