Open AccessA 20-K, 600-W, Cryocooler-Based, Supercritical Helium Circulation System for the SPARC Toroidal Field Model Coil Program
Author(s) -
Philip C. Michael,
Theodore Golfinopoulos,
Ernest Ihloff,
Alexander Zhukovsky,
Shane Schweiger,
Vincent Fry,
Colin O'Shea,
Amy Watterson,
Daniel Nash,
Rui F. Vieira,
Jeffrey Doody,
Raheem Barnett,
Erik A. Voirin,
Larry Bartoszek,
Richard F. Lations,
Zachary S. Hartwig
Publication year - 2023
Publication title -
ieee transactions on applied superconductivity
Language(s) - English
Resource type - Journals
eISSN - 1558-2515
pISSN - 1051-8223
DOI - 10.1109/tasc.2023.3332266
Subject(s) - fields, waves and electromagnetics , engineered materials, dielectrics and plasmas
From June 2019 to July 2021, the MIT Plasma Science and Fusion Center, in collaboration with Commonwealth Fusions Systems, designed, built, and commissioned a test facility at the Massachusetts Institute of Technology to evaluate the performance of a rare-earth-yttrium-barium-copper-oxide-based, 2.9-m tall, 1.9-m wide Toroidal Field Model Coil (TFMC) for the SPARC tokamak. This article presents the facility's supercritical helium (SHe) circulation system design and measured performance. The facility employed a forced-flow SHe circulation loop cooled by cryocoolers to provide a nominal cooling power of 600 W at 20 K and up to 70 g/s SHe flow to the TFMC at an absolute pressure of 20 bar. The reliance on cryocoolers as the facility's cooling source was an ideal arrangement. Procurement costs were modest, acquisition time was reasonable, and seating requirements were minimal. A steady improvement in cryocooler design provided a simple-to-use system with sufficient cooling capacity for our needs. Extensive, closed-loop analyses were performed both to support this procurement and to finalize the overall design of the SHe cooling circuit. The SHe system worked reliably, permitting flexible operation of the TFMC test facility under all working conditions.