Abstract
The US ITER Domestic Agency is responsible for supplying seven Central Solenoid Modules (CSM) to the ITER organization. The modules are fabricated by General Atomics (GA). As part of the fabrication process, all CSMs undergo factory acceptance testing (FAT) prior to shipment to the IO. The FAT includes Paschen testing the CSMs up to 15 kV between 1e-3 and 100 mbar, and up to 30 kV at ambient conditions. During post-cooldown Paschen testing of CSM6, there was a fault on one of the terminal breakout locations which required a repair. This location of the fault consisted of complex geometry that required development of advanced insulation repair methods to return the module to Paschen-tight condition. Successful insulation repairs typically require sufficient compression to achieve a Paschen-tight seal of the applied insulation to the underlying surfaces. Typically for circumferential shapes, compression is achieved utilizing shrink tape or silicone tape wrapped around the perimeter. The complex geometry of CSM6 terminal required research into other compression methods including vacuum bagging, expanding foam, and externally pressurized bladders of complex shapes. Multiple test articles were created to replicate the shape of the fault area and repair methods were developed and Paschen tested to 30 kV, from 1e-3 to 1000 mbar. This paper will discuss the development of the qualified repair process for the complex geometry of the CSM6 terminal, and present to the magnet community the lessons learned from that development.
| Original language | English |
|---|---|
| Article number | 4200205 |
| Journal | IEEE Transactions on Applied Superconductivity |
| Volume | 36 |
| Issue number | 3 |
| DOIs | |
| State | Published - 2026 |
Funding
This work was supported in part by the U.S. Department of Energy, in part by the Office of Science, in part by the Office of Fusion Energy Sciences, in part by UT-Battelle/Oak Ridge National Laboratory under Award 4000103039 and Award DE-AC05-00OR22725, and in part by UT Battelle, LLC under Contract DE-AC05-00OR22725 through the U.S. Department of Energy. The authors are grateful to the GA MTC’s technician staff for their tireless efforts in developing and testing new methods utilizing their expertise. Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization or of the European Commission. Received 28 July 2025; revised 15 September 2025 and 17 September 2025; accepted 18 September 2025. Date of publication 1 October 2025; date of current version 10 October 2025. This work was supported in part by the U.S. Department of Energy, in part by the Office of Science, in part by the Office of Fusion Energy Sciences, in part by UT-Battelle/Oak Ridge National Laboratory under Award 4000103039 and Award DE-AC05-00OR22725, and in part by UT Battelle, LLC under Contract DE-AC05-00OR22725 through the U.S. Department of Energy. (Corresponding author: Bryce Fledderman.) Bryce Fledderman, Kenneth Khumthong, Nikolai Norausky, John Smith, Bob Johnson, Thiago Mondino Nascimento, Matthew Schaeffer, Dane Robinson, and Steve Patlan are with General Atomics (GA), San Diego, CA 92121 USA (e-mail: [email protected]).
Keywords
- Central solenoid
- ITER project
- complex geometry repair
- high voltage breakdown
- insulation repair
- magnet testing
- paschen testing
- superconducting magnets