High Temperature Oxidation of Metals and Ceramics: Oxidation of Metals and Accident Tolerant Fuel
Sponsored by: TMS Corrosion and Environmental Effects Committee
Program Organizers: Kenneth Kane, Oak Ridge National Laboratory; Elizabeth Sooby, University Of Texas At San Antonio; Patrick Brennan, General Electric Research; Lavina Backman, U.S. Naval Research Laboratory; Kinga Unocic, Oak Ridge National Laboratory; Richard Oleksak, National Energy Technology Laboratory; David Shifler, Office of Naval Research; Raul Rebak, GE Global Research
Tuesday 8:00 AM
October 11, 2022
Room: 335
Location: David L. Lawrence Convention Center
Session Chair: Richard Oleksak, National Energy Technology Laboratory; Elizabeth Sooby, University of Texas - San Antonio
8:00 AM Invited
GE's Accident Tolerant Fuel Cladding: An Overview of Accident Scenario Testing: Andrew Hoffman1; Raul Rebak1; Evan Dolley1; Rajnikant Umretiya1; Michael Worku1; 1GE Research
Over the past decade General Electric (GE,a collaboration between GE Research, GE-Hitachi, and Global Nuclear Fuel) has worked intensively on the development of accident tolerant fuel cladding for the current light water reactor fleet as well as for the future fleet of small modular reactors. Concepts that are being developed include a proprietary coating for Zirc-2 tubing and monolithic thin walled FeCrAl tubing for fuel cladding and SiC-SiC composite development for accident tolerant fuel channels. This talk will provide an overview of testing performed on these concepts to simulate accident conditions, and discuss future planned worked for the qualification and commercialization of these concepts.
8:30 AM
Burst Behavior and Oxidation Resistance of Cr-coated Zircaloy-4 Accident Tolerant Fuel Cladding: Mackenzie Ridley1; Samuel Bell2; Ben Garrison1; Tim Graening1; Kenneth Kane3; Nathan Capps1; 1Oak Ridge National Laboratory; 2University of Tennessee; 3Formerly ORNL, currently Applied Physics Laboratory
Accident tolerant fuel cladding concepts are being researched to enhance the safety and reliability of light water nuclear reactors without disrupting energy efficiencies. Cr-coated zirconium alloys represent a leading cladding concept for industrial application. In this work, unirradiated Cr-coated Zircaloy-4 was exposed to simulated loss of coolant accident conditions, where claddings were internally pressurized and rapidly heated to examine cladding burst behavior. The effect of Cr coatings on burst behavior, rupture geometry, and oxidation resistance will be discussed. This work was supported by the United States Department of Energy, Office of Nuclear Energy, Advanced Fuels Campaign.
8:50 AM Invited
Material Compatibility in Supercritical CO2 at 450°-650°C: Bruce Pint1; Rishi Pillai1; Michael Lance1; James Keiser1; 1Oak Ridge National Laboratory
Direct-fired supercritical CO2 (sCO2) power cycles are being commercialized to revolutionize fossil energy as a low-emission power source. To lower the cost of this technology, less expensive steels are needed in the lower temperature segments of the cycle. However, there are concerns about internal carburization of steels in this environment. In addition to 9-12%Cr ferritic-martensitic (FM) steels and conventional austenitic stainless steels (SS), additional candidates are being evaluated including advanced austenitic steels, high Fe content Ni-based alloys and protective coatings. A consistent observation is that thin, protective Cr-rich oxides appear to prevent C ingress and the associated room temperature embrittlement. However, when Fe-rich oxides form, C ingress occurs with rates dependent on the exposure temperature. The C diffusion profiles in FM and SS specimens are being quantified at 550°-650°C in order to validate a predictive model for these alloys and determine a maximum use temperature for this application.
9:20 AM
The Effect of Pressure on the Oxidation of Steels in Direct-fired Supercritical CO2 Power Cycle Environments: Casey Carney1; Richard Oleksak1; Joseph Tylczak2; Ömer Doğan3; 1LRST; 2NETL (retired); 3NETL
The effect of elevated pressure on corrosion resistance is a key materials selection concern in direct-fired supercritical CO2 power cycles. Several commercial steels were exposed to direct-fired conditions (95CO2 – 4H2O – 1 O2) at 550 °C h at both atmospheric pressure (0.1 MPa) and supercritical conditions (20 MPa) for over 2,000 hours. Supercritical conditions significantly affected the oxidation behavior, where most of the steels performed worse compared to atmospheric pressure exposures. Most notably, 18Cr-10Ni steels (304H and 347H) formed protective Cr-oxide scales at 0.1 MPa but failed to do so at 20 MPa, where only highly alloyed austenitic steels (309H, 310S, 800) exhibited protective behavior. Increased spallation was observed at high pressure supercritical conditions, whereas little was observed at atmospheric pressure. The mechanisms responsible for these differences in oxidation behavior with pressure changes and the implications for materials selection in direct-fired sCO2 cycles will be discussed.
9:40 AM
Effect of Pressure on High-temperature Corrosion of Ni Alloys in Supercritical CO2 Containing Impurities: Richard Oleksak1; Casey Carney1; Joseph Tylczak1; Ömer Doğan1; 1National Energy Technology Laboratory
Direct-fired supercritical CO2 (sCO2) power cycles offer the potential for high-efficiency power production with built-in carbon capture. A primary difference from conventional (indirect) sCO2 power cycles is that the CO2-rich working fluid contains impurities related to the combustion process, most notably H2O and O2. Prior research has shown good compatibility of Ni-based alloys in pure sCO2, where robust chromia scales are formed. Alternatively, data in sCO2 containing impurities is very limited. In this study, we exposed several commercially available chromia-forming Ni alloys to 95%CO2-4%H2O-1%O2 at 750°C and 20 MPa in a flowing autoclave for up to 2500 h. For comparison, the alloys were also exposed to the same environment at atmospheric pressure (0.1 MPa). Systematic analysis suggested that the alloys exposed at high pressure experienced notable chromia volatilization, raising compatibility concerns. The factors which affect the rate of volatilization and the implications for materials selection are discussed.
10:00 AM Break
10:20 AM
Atomic Scale Dynamics of Initial Stage Copper Oxidation Using In Situ ETEM and Correlated DFT Simulations: Meng Li1; Matthew Curnan1; Richard Garza1; Stephen House1; Wissam Saidi1; Judith Yang1; 1University of Pittsburgh
The initial stage of metal oxidation is essential for rational design and control of oxides for applications in catalysts, sensors, and corrosion. Despite ample research on bulk oxidation, little is known on the initial oxidation process. In this work, we use correlated in situ Environmental TEM, DFT simulation, quantitative data extraction and statistical analysis to investigate the dynamic atomic process of initial oxidation from surface reconstruction to oxide growth. Uneven oxidation is observed on stepped Cu surface during surface reconstruction[1]. Epitaxial Cu2O islands on Cu(100) were observed to grow via an unusual layer-by-layer growth mechanism along Cu2O(110)[2]. Correlated DFT simulations and advanced data analysis were performed to uncover the mechanism beneath the observed phenomena. Our results shed new lights on surface oxidation investigation at atomic scale. [1] Li, M. et al. Nano Lett. 22, 1075–1082 (2022).[2] Li, M. et al. Nat. Commun. 12, 2781 (2021).
10:40 AM Invited
High Temperature Oxidation Behavior of Fe- and Ni-Based Alloys Fabricated by Additive Manufacturing: Sebastien Dryepondt1; Marie Romedenne1; Rishi Pillai1; Kinga Unocic1; Bruce Pint1; 1Oak Ridge National Laboratory
Additive manufacturing (AM) offers the unique opportunity of fabricating complex components such as high temperature heat exchangers or cooled turbine blades. Laser powder bed fusion or electron beam melting result in rapid cooling rates and thus specific microstructures that impact the alloy properties, including the alloy high temperature oxidation resistance. Elongated grains and cellular structures are good instances of microstructural features that can affect the oxidation behavior of Ni and Fe-based alloys. In addition, AM alloy chemistries often differ from the chemistries of wrought or cast counterparts, leading to significant differences in the oxide scales grown at 700-800°C in air or humid atmospheres. For example, variations in Si and/or Mn concentrations impact the oxidation resistance of Ni-based Hastelloy X or Fe-based HK30Nb. Finally, surface treatments might not be possible for components with internal features and the rougher AM surface finish needs to be accounted for when analyzing oxidation rates.
11:10 AM
Study of the Pre-oxidation Effect on Long-term Oxidation Properties of Porous Fe22Cr Alloy: Damian Koszelow1; Sebastian Molin1; Agnieszka Drewniak1; Piotr Jasiński1; 1Gdansk University of Technology
Recently, ferritic porous alloys have been employed in gas membranes, sensor systems, or as mechanical supports in solid oxide cells (SOCs). They are an alternative material to ceramic components allowing a decreased price of the devices. The disadvantage of using porous alloys is their high-temperature (>500 °C) oxidation. The formation of the oxide scale leads to a decrease of porosity, breakaway oxidation, and failure of the component. In this work, we evaluated the effect of the initial pre-oxidation step (carried out at elevated temperature: 900 - 950 °C) on the long-term oxidation properties at working temperature (at 700 °C). The materials studied are porous (~30 % total porosity) Fe22Cr alloys. The lifespan of the "untreated" and pre-oxidized alloy was established and compared using the simple prediction model. We will present the obtained results and discuss the predicted lifetime of porous steel components in the context of high-temperature applications.
11:30 AM
Alumina-scale Establishment Behavior on Ni-6Al-yCr-2X (y = 4, 6, 8; X = Nb, Ta, Re) Model Alloys during High-temperature Oxidation: Rafael Rodriguez De Vecchis1; Rishi Pillai2; Brian Gleeson1; 1University of Pittsburgh; 2Oak Ridge National Laboratory
Due to its superior high-temperature properties, nickel-based superalloys continue to be a key material for a vast set of high-temperature applications, including aero-engine and power generation. During the last decades, new generations of these alloys with judiciously controlled chemistries have emerged. However, a fundamental understanding of the influence minor-element additions have on oxidation behavior is still not well established. Systematic studies are currently missing and contrary inferences on their overall oxidation impact continue to exist in the literature. The present work seeks to elucidate the effects that minor additions of Nb, Ta, and Re have on the oxidation behavior of alumina-scale forming, γ-Ni alloys. In particular, this investigation focuses on describing the nature of the so-called third-element effect and the influence these elements have on promoting internal-to-external alumina scale transition.