Sub-divertor fuel isotopic content detection limit for JET and its impact on ICRF core heating and DTE2 operation
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- French Alternatives Energies and Atomic Energy Commission (CEA), Saint Paul-lez-Durance (France). Inst. for Magnetic Fusion Research (IRFM)
- Royal Military Academy, Brussels (Belgium)
- Culham Science Centre (United Kingdom and Northern Ireland)
- Forschungszentrum Jülich GmbH (Germany)
The ability to detect and control fuel isotopic content down to a 1% concentration level is greatly important for the upcoming JET DTE2 campaign, as well as its associated TT and DD phases. A reduction of H minority concentration even from 2% down to 1% is shown in this paper to have significant impact on the effectiveness of ion cyclotron range of frequencies core heating, while the ability to maintain T or D concentration at or below 1% is critical to limiting fusion neutron generation in the DD and TT phases, correspondingly. The sub-divertor measurement of (global) isotopic concentration, based on Penning-activated optical spectroscopy, can deliver minimally this 1% detection for DTE2 as long as light collection from the Penning emission can be optimized and gradual window transmission deterioration can be minimized. Here, this is simulated with a statistical analysis developed to understand the uncertainty sources in the JET DTE1 data, as well as to guide the optimization of an upgraded, fuel-isotopic content (and helium-ash concentration) gas analysis system for the JET divertor in preparation for DTE2. While this random error can be reduced to allow measurement substantially below 1% concentration, analysis also shows a systematic error of up to 1% understood to be due to plasma–surface interactions in the Penning excitation, suggesting that 1% may still be the low-end limit for the sub-divertor measurement, unless a Penning-source conditioning approach is also developed.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); Euratom
- Contributing Organization:
- EUROfusion Consortium; JET ICRH Team; JET Contributors
- Grant/Contract Number:
- AC05-00OR22725; 633053
- OSTI ID:
- 1649148
- Journal Information:
- Nuclear Fusion, Vol. 60, Issue 1; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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