Image processing for Plasma Facing Components protection

This project is the result of a research collaboration with the Max Planck Institute for Plasma Physics (IPP) located in Greifswald (Germany) within the H2020 EUROfusion project where UPC is a LTP of CIEMAT.

Wendelstein 7-X is the largest prototype of a fusion reactor of the "Stellarator" family (see this piece of news¹ for general information, or this more recent one about fusion and the ITER², and this spectacular 360º Virtual Tour Panorama of W7-X, where a mouse click leads you right into the plasma vessel or the experimentation hall and other facilities). The first operation phase (OP1) started in 2017, and IPP offers now a large amount of the resulting data (videos, images) for research.

¹ D. Clery, «The bizarre reactor that might save nuclear fusion», Science | AAAS, Oct. 21st 2015. 
² Michael Finkel (text), Paolo Verzone (photographs) «Inside the colossal quest for limitless energy from nuclear fusion», National Geographic Magazine, 248(5), pp. 14-43, Nov. 2025.

Fig.1  View of the Weldenstein 7-X coil System

The collaboration of GPI in this project is included in EUROfusion WPS1. The main purpose of WPS1 is the preparation, execution and exploitation of Wendelstein 7-X campaigns. In particular, the Project Project Management Plan 2019/20, foresees GPI contribution within Key milestone 1.3 in order to prepare and develop control and data acquisition systems and diagnostics addressing objectives for safe steady-state operation and employ surveillance diagnostics for the detection of wall loads, hot spots. The relevant objectives are grouped within task S1.P2.T6 Image Processing and Object Detection:

• S1.P2.T6 (a) Develop image processing and machine learning tools for detection, tracking and classification of thermal events on the Plasma Facing Components or PFCs (strike-lines, leading edges, hot spots, surface layers, delaminations, reflections),  from thermal images that observe the plasma during operation.
              
  Fig.2a  Thermal events on PFCs (IR image)                      Fig.2b  Animation sequence of a strike line
  
• S1.P2.T6 (b) Develop a real-time NN-based heat flux THEODOR estimation for the real-time image analysis system for PFC protection.
• S1.P2.T6 (c) Develop image processing tools for video and Ha data analysis for automatic plasma events detection and their correlation with the magnetic topology. In this case, a different set of 10 visible camera sensors (EDICAMs @400fps) have observed anomalies in the plasma behavior that IPP has the challenge to study, classify and detect in the 50h of footage they have available. A first ontology of anomalies is: falling debris, MARVEs, Pellets, UFOs and hotspots.
  
  Fig. 3 Anomaly in the reactor core: falling debris (EDICAM)
  

The results of the collaboration are to be reported the end of 2019 (S1.P.2.D6.1: Interim report on S1.P.2.T6) and 2020 (S1.P.2.D6.2: Final report S1.P.2.T6).

Internal reports resulting from the students who participate in the collaboration are as follows:

• in progress:
   - D. Vizcarro Carretero, “Thermal Image Processing for Plasma Facing Components protection,” Degree Thesis, ETSETB-UPC
   - J.-H. Kim Jung, “Spatial Map for Thermal Image Processing at Wendelstein 7-X,” Degree Thesis, ETSETB-UPC
   - A. Palacios Corral, “Automatic detection of visible events in fusion reactors,” MsTh Master in Advanced Telecommunication Technologies, ETSETB-UPC
• L. Cabello Quelart, “Tracking and classification of anomalies in Wendelstein 7-X fusion reactor,” Degree Thesis (en), ETSETB-UPC, Barcelona, 28-Oct-2020
• R. Clemente Bonjour, “Detection, tracking and classification of thermal events on Plasma Facing Components,” MsTh Master in Telecomunications Engineering ETETB-UPC 9-Sep-2020
• M. Cobos Arnalot, “Anomalies detection in the visible spectrum of Plasma Physics at Wendelstein 7-X,” MsTh Master in Computer Vision, UAB-UPC-UPF-UOC, Barcelona, 20-Jul-2020
• A. Cano Aguilera, “Anomaly detection using Computer Vision for fusion power generation,” Degree Thesis, ETSETB-UPC, Barcelona, 17-Jul-2020
• S. Quiceno, “Detection of hot spots and heat lines in thermal images of a nuclear fusion reactor,” Degree Thesis (es), ETSETB-UPC, Barcelona, 6-Feb-2020
• A. Moreno, “Thermal events detection in the infrarred Spectrum at Wendelstein 7-X,” Degree Thesis (en), ETSETB-UPC, Barcelona, 5-Feb-2020
• A. Palacios Corral, “Anomalies detection in the infrared spectrum of Plasma Physics at Wendelstein 7-X,” Degree Thesis (cat), ETSETB-UPC, Barcelona, 1-Jul-2019

Other contributors:

• Ivan Caminal, technical support (Apr-Nov 2019)