The near infrared imaging system for the real-time protection of the JET ITER-like wall

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This paper describes the design, implementation and operation of the near infrared (NIR) imaging diagnostic system of the JET ITER-like wall (JET-ILW) plasma experiment and its integration into the existing JET protection architecture. The imaging system comprises four wide-angle views, four tangential divertor views, and two top views of the divertor covering 66% of the first wall and up to 43% of the divertor. The operation temperature ranges which must be observed by the NIR protection cameras are, for the materials used on JET: Be 700 degrees C-1400 degrees C; W coating 700 degrees C-1370 degrees C; W bulk 700 degrees C-1400 degrees C. The Real-Time Protection system operates routinely since 2011 and successfully demonstrated its capability to avoid the overheating of the main chamber beryllium wall as well as of the divertor W and W-coated carbon fibre composite (CFC) tiles. During this period, less than 0.5% of the terminated discharges were aborted by a malfunction of the system. About 2%-3% of the discharges were terminated due to the detection of actual hot spots.

Original languageEnglish
Article number014027
Number of pages7
JournalPhysica Scripta
Publication statusPublished - Dec 2017
MoE publication typeA1 Journal article-refereed
EventInternational Conference on Plasma-Facing Materials and Components for Fusion Applications - Düsseldorf, Germany
Duration: 16 May 201719 May 2017
Conference number: 16


  • imaging diagnostics
  • real-time protection system
  • hot spots
  • JUVIL software
  • image processing

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