Composite Materials for Nuclear Applications: Ceramic Composites
Sponsored by: TMS Structural Materials Division, TMS: Composite Materials Committee, TMS: Nuclear Materials Committee
Program Organizers: Anne Campbell, Oak Ridge National Laboratory; Dong Liu, University of Oxford; Rick Ubic, Boise State University; Lauren Garrison, Commonwealth Fusion Systems; Peng Xu, Idaho National Laboratory; Johann (Hans) Riesch, Max Planck Institute for Plasma Physics
Tuesday 8:30 AM
March 16, 2021
Room: RM 52
Location: TMS2021 Virtual
Session Chair: Peng Xu, Idaho National Laboratory
8:30 AM Invited
SiGA SiC-SiC Composites Development for Accident Tolerant Fuel: Christian Deck1; Rolf Haefelfinger1; Jon Sheeder1; Lucas Borowski1; Sarah Oswald1; Joel Kosmatka1; Ryan Hon1; Kirill Shapovalov1; Sean Gonderman1; Jack Gazza1; Christina Back1; 1General Atomics
Engineered SiGA SiC-SiC composites are being developed to offer improved performance in normal operation and accident conditions for cladding and fuel assembly structures in light water reactors. Recent efforts at General Atomics have expanded the scale of cladding components that can be fabricated to 1m and longer, and have demonstrated consistent ability to meet demanding dimensional tolerances and surface roughness requirements. Improved cladding and fuel rod designs that offer enhanced pellet-cladding heat transfer have been tested, showing significant improvements in thermal performance of the cladding. This approach supports the use of high burn-up, high enrichment fuel with SiC-SiC-based cladding. Corresponding cladding performance models have been developed to simulate in-operation stresses, incorporating more realistic representation of internal porosity and micro-cracking within the composite. The fabrication, characterization, and modeling progress support current and planned test reactor irradiations to prepare for lead test rod irradiations of SiGA accident tolerant components.
9:00 AM
Development of PVD Cr Coatings for Hydrothermal Corrosion Mitigation of SiC-SiCf Fuel Cladding in LWRs: Kyle Quillin1; Hwasung Yeom1; Tyler Dabney1; John Lacy1; Taeho Kim1; Sergey Chemerisov2; Adrien Couet1; Kumar Sridharan1; 1University of Wisconsin, Madison; 2Argonne National Laboratory
SiC-SiCf composites are under consideration as a next-generation fuel cladding material for light water reactors (LWRs) based on their high temperature stability and resistance to irradiation damage. SiC-SiCf cladding offers greatly improved safety performance in accident conditions compared to current Zr-alloy cladding. One challenge in the implementation of this composite is the hydrothermal corrosion of SiC under normal operating conditions. We demonstrate the feasibility of PVD Cr coatings as an environmental barrier to mitigate hydrothermal corrosion of SiC. Two types of magnetron sputter technologies were utilized to deposit Cr coatings on CVD SiC substrates. Detailed microstructural analysis has been performed to correlate deposition parameters to corrosion performance in both static and flowing water under prototypical LWR conditions. The results of this study and the effects of water radiolysis on corrosion will be discussed, with the goal of enhancing the viability of advanced SiC-SiCf composites as cladding for LWR applications.
9:20 AM
Corrosion and TEM Analysis of CVD and PVD Coatings for BWR Accident Tolerant Fuel Cladding: Ryan Schoell1; Joey Kabel2; Sebastian Lam3; Kirill Shapovalov4; Peter Hosemann3; Djamel Kaoumi1; 1North Carolina State University; 2University of California Berkeley ; 3University of California Berkeley; 4General Atomics
Coated SiC-SiC Composite Material has been proposed as a possible accident tolerant cladding material. To select the right coating, several coatings such as ZrN, TiN, Ti/TiN, TiC, and a Zr-Cr-Ti tri-layer were envisioned either by Chemical Vapor Deposited (CVD) or Physical Vapor Deposited (PVD). As-received and heat treated samples of the best candidates were subjected to simulated boiling water reactor conditions (288 ˚C, 1100 psi, and 2 ppm DO). Corrosion was quantified using a high precision balance to track weight changes after various times in the autoclave. Post-experiment analysis was performed with Secondary Ion Mass Spectroscopy (SIMS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) equipped with Energy Dispersive Spectroscopy (EDS) detectors. Mechanical testing was also employed to test the adherence of each coating.
9:40 AM
Novel Fiber Fretting Technique for Tribological Properties of Composite Interphases: Joseph Kabel1; Thomas Edwards2; Caroline Hain2; Tatiana Kochetkova2; Johann Michler2; Peter Hosemann1; 1University of California, Berkeley; 2EMPA
Ceramic matrix composites exhibit excellent high temperature properties and are candidate materials for application as nuclear fuel cladding. The strength and deformation behavior of these composites are intrinsically tied to the properties of the fiber/matrix interphase. This research introduces a novel technique to evaluate the fundamental friction and wear characteristics of these interfaces. A case study on SiCf/PyC/SiCm composites applies in situ fiber fretting to investigate the kinetic friction coefficient (μk) and cyclic wear characteristics. Testing was carried out as a function of fiber type, PyC thickness (≈10, 500, 1200nm), cycle count (10, 100, 1000), and frequency (1, 5, and 10 Hz). The friction coefficient and behavior changed with cycle length as it related to transition from adhesive to abrasive friction mechanisms. SEM fractography provided insights to tribological evolution from adhesive sliding to three-body abrasive wear. The surface structural disorder contribution to adhesive resistance was investigated using Raman spectroscopy.