Speaker: Stuart A. Maloy, National Laboratory Professor with the Department of Nuclear Engineering at the University of New Mexico
Title: Process Development of Ferritic Steels for High Dose Reactor Applications
Abstract: The Nuclear Technology R&D program is investigating options to transmute minor actinides. To achieve this goal, new fuels and cladding materials must be developed and tested to high burnup levels (e.g. >20%) requiring cladding to withstand very high doses (greater than 200 dpa) while in contact with the coolant and the fuel. New ferritic/martensitic and ferritic Oxide Dispersion Strengthened (ODS) alloys are being developed with improved radiation tolerance. The ferritic/martensitic alloys include slight variations in the composition of HT-9 to improve resistance to low temperature embrittlement and void swelling. This material maintained 5% uniform elongation after irradiation to 6 dpa at 290C while all other alloys exhibited less than 2% uniform elongation. In recent research, ferritic/martensitic steels have been produced using additive manufacturing showing similar properties to wrought materials after normalizing and tempering the microstructure. Also, in the as-deposited condition, additively manufactured grade 91 steel shows a significant increase in yield strength at 300 °C and 600°C over that measured for wrought normalized and tempered material. The irradiation tolerance of these alloys is being measured through high dose ion irradiations. In addition, ferritic ODS alloys are being processed into tube form and tested for future nuclear applications. Tubes over 3 feet in length are being produced by pilger processing. Recent progress in high dose irradiated materials testing and materials development will be presented.
Bio: Dr. Stu Maloy been a Technical Staff Member at Los Alamos National Laboratory (LANL) for 26 years, and he is currently the advanced reactor core materials technical leader for the Fuel Cycle Research and Development’s Advanced Fuels campaign at LANL. He has a Bachelors (’89) Masters (’91) and PhD (’94) in Materials Science from Case Western Reserve University and is a registered PE in Metallurgy. He has extensive expertise in characterizing and testing the properties of metallic and ceramic materials in extreme environments such as under neutron and proton irradiation at reactor relevant temperatures. This includes testing the mechanical properties (fracture toughness and tensile properties) of Mod 9Cr-1Mo, HT-9, 316L, 304L, Inconel 718, Al6061-T6 and Al5052 after high energy proton and neutron irradiations using accelerators and fast reactors. Characterization of materials after testing includes using transmission electron microscopy for analyzing defects such as dislocations, twins and second phases, using high resolution electron microscopy to characterize defects at an atomic level and nanoscale mechanical testing. He has an extensive publication record of >160 peer reviewed technical publications and hundreds of presentations.
Seminar Host: Sid Pathak
Webinar Link: https://iastate.zoom.us/j/97445884023