The Importance of Wire Characterization to the Development of Fusion Magnets

by Ms JL Cheng (CFS), Ms Aliya Greenberg (CFS)

Tuesday 1 Nov 2022, 14:00 → 15:00 US/Pacific

0006-CR (47)

Speakers: JL Cheng & A Greenberg, Commonwealth Fusion Systems

Host: Ian Pong

Zoom: https://lbnl.zoom.us/j/5104867866

Title: The Importance of Wire Characterization to the Development of Fusion Magnets

Abstract: 

Commonwealth Fusion Systems (CFS) is pursuing a high-field approach to fusion energy, which enables the development of smaller, lower cost tokamaks on a faster timeline. CFS has recently completed the manufacturing and demonstration of a Toroidal Field Model Coil, and is scheduled to demonstrate a net-energy fusion device, SPARC, by 2025 and commercialize fusion with ARC in the 2030s. The key enabling technology for the design of such high-field magnets is 2G REBCO HTS wire, tens of thousands of kilometers of which are required. Magnets in SPARC and ARC will operate at high field (~ 20 T) and low temperature (~ 20 K) and will be subject to significant mechanical force and neutron flux. HTS wound into magnets will be positioned in varying orientations relative to varying background fields, and will experience additional handling during winding and soldering processes. Therefore detailed characterization of the critical current of HTS wires as a function of field, temperature, and angle are essential for the design and confirmation of conformance of HTS used in high-field fusion magnets. This presentation will further discuss relevant material requirements, including throughput and cost effectiveness, as well as design-relevant data and statistical testing methods.

Biographies:

JL has been drawn to fusion by its challenges and promise for sustainable energy, ever since their time as an undergraduate student. JL joined CFS in late 2018 and has been working on 2G HTS tape and magnet testing ever since. They had the unique opportunity to travel to test HTS at a number of labs, including Robinson Research Institute, Tohoku University, and the NHMFL, and to work on a number of projects. These include initial HTS vendor evaluation, qualification of 500 km of HTS for the Toroidal Field Model Coil (TFMC), process scale-up, as well as participating in the testing and analysis of the TFMC and associated data. JL’s most recent work has been on statistical acceptance of HTS, the design of a cryogenic tensile testing machine for validating quench models, and the creation of automated analysis tools for critical current extrapolation.

Aliya joined Commonwealth Fusion Systems (CFS) in early 2020. Her hardware projects include designing an automated HTS respooler, a cable layer separator for applying turn insulation, and, alongside JL, a cryogenic tensile testing machine for validating quench models. She has participated in numerous 2G HTS qualification efforts and studies including leading an examination of correlations in Ic across the phase surface. She also had the opportunity to work as a test operator for both the Toroidal Field Model Coil (TFMC) and the Wisconsin HTS Axisymmetric Mirror (WHAM) magnet test. Outside of 2G HTS tape and magnet testing and development, she has led several projects critical to the SPARC tokamak, including building and qualifying and outgas test rig for in-vessel components, and qualifying flow across fueling valves.