Transmutation Effects in Fusion Reactor Materials: Critical Challenges & Path Forward: Facilities, Characterization & Experimental Validation
Sponsored by: TMS Structural Materials Division, TMS: Nuclear Materials Committee
Program Organizers: Arunodaya Bhattacharya, Oak Ridge National Laboratory; Steven Zinkle, University of Tennessee; Philip Edmondson, The University Of Manchester; Aurelie Gentils, Université Paris-Saclay; David Sprouster, Stony Brook University; Takashi Nozawa, National Institutes for Quantum and Radiological Science and Technology (QST); Martin Freer, University of Birmingham
Monday 8:30 AM
March 20, 2023
Room: 27B
Location: SDCC
Session Chair: Grace Burke, Oak Ridge National Laboratory; Philip Edmondson, University of Manchester
8:30 AM Invited
Irradiation Spectrum, Transmutation, and Supporting Materials Use Next Generation Fusion Systems: Lance Snead1; David Sprouster2; Steven Zinkle3; Brian Wirth3; Yutai Katoh4; Ethan Peterson5; 1Stony Brook University; Massachusetts Institute of Technology; 2Stony Brook University; 3University of Tennessee; 4Oak Ridge National Laboratory; 5Massachusetts Institute of Technology
Both our understanding of materials phenomena and the qualification of fusion components necessary to realize fusion power hinge on our ability to irradiate materials in a range of dynamic cascade and transmutation conditions. These conditions are dependent on reactor design, being highly dependent on geometric considerations and materials choices, and while the helium generation in steel is a crucial issue facing fusion power development, it is but one example of a wide array of important transmutation materials science issues.This presentation will discuss the implication of design on the relative importance of neutron-induced transmutation to critical components of the fusion systems. The underlying transmutation science of these materials will be reviewed and our ability to support the modeling-based description of irradiation behavior necessary to support use of these materials in design discussed. Finally, the range of irradiation test beds necessary to support these activities will be presented.
9:10 AM Cancelled
The University of Birmingham Accelerator Driven Neutron Facility: Martin Freer1; 1University of Birmingham
The University of Birmingham, UK, has been funded to develop an accelerator driven neutron irradiation facility. The facility is constructed and starts operation in September 2022 and is designed to support a user community interested in irradiation effects of neutrons for fusion and fission applications, together with fundamental science. The accelerator is a 30-50mA dc proton machine which accelerates protons to 2.6 MeV which then are incident on a rotating, water cooled, lithium target, converting the protons to neutrons via the 7Li(p,n)7Be reaction. A variety of neutron irradiation stations are being designed to operate with neutron fluxes of 10^13 neutrons/cm^2/s. This facility is combined with a MC40 cyclotron which can accelerate protons to an energy of 40MeV, and additionally deuterons, 3He and 4He. Combined these irradiation facilities offer users the ability to perform neutron and proton irradiation studies and in the future dual beam capability.
9:30 AM
Advanced Synchrotron Characterization Techniques for Fusion Materials Science: David Sprouster1; J Trelewicz1; T Koyanagi2; W Zhong2; Y Katoh2; L Snead1; 1Stony Brook University; 2Oak Ridge National Laboratory
In this work, we describe our recent efforts employing advanced, multimodal synchrotron-based characterization techniques in concert with electron microscopy to quantify radiation, and transmutation-induced microstructural changes in fusion-relevant structural materials including; tungsten; advanced steels; and silicon carbide. When coupled with electron microscopy, synchrotron-based characterization techniques provide complimentary quantitative insights across multiple length scales needed to fill critical knowledge gaps, and predict long-term behavior and performance. We also highlight new opportunities in leveraging synchrotron-based techniques to address fundamental and applied materials science challenges to aid in developing a detailed physical understanding of radiation-induced microstructures in materials for fusion energy applications
9:50 AM
Tracking Neutron-irradiation Induced Transmutation Using Atom Probe Tomography and Neutron Inventory Calculations: Philip Edmondson1; Mark Gilbert2; 1The University of Manchester; 2UKAEA
Tungsten is proposed as a plasma-facing material for nuclear fusion reactors; however, it undergoes transmutation to other species, especially rhenium and osmium, resulting in second-phase-precipitates. Atom probe tomography/microscopy can visualize all precipitates present; however, the composition using isotope natural abundances is incorrect when examining neutron-irradiated tungsten due to high transmutation rates. Here, the time-of-flight spectrometer of the atom probe microscope is used in conjunction with neutron-inventory calculations of the experiment to examine the formation and chemistry of the second-phase-precipitates of pure tungsten neutron-irradiated to doses up to ~2 displacements per atom at temperatures above and below the vacancy-mobility temperature to investigate the effect of defect mobility on second phase formation. Transmutation-corrected atom probe tomography results suggest the composition of the precipitates is approaching that of the sigma phase, far from the compositions required to be the chi phase as suggested by analysis of the diffraction patterns in the TEM data.