Abstract
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 here 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. 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.
| Original language | English |
|---|---|
| Article number | 016021 |
| Journal | Nuclear Fusion |
| Volume | 60 |
| Issue number | 1 |
| DOIs | |
| State | Published - 2020 |
Funding
This work was supported, in part, by the US Department of Energy under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. Continuing support and encouragement from JET management and task force leaders for this collaborative work is gratefully acknowledged. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. a This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). b Current address: Institute of Plasma Physics of the Czech Academy of Sciences, Za Slovankou 3, 18200 Prague, Czech Republic. c Current address: National Research Nuclear University MEPhI, 31, Kashirskoe sh., 115409, Moscow, Russian Federation. d Current address: National Institute for Laser Plasma and Radiation Physics, Bucharest-Magurele 077125, Romania. e Current address: ITER Organization, Route de Vinon-sur-Verdon, 13067 St. Paul-lez-Durance, France. f See the author list of Jacquet et al 2017 (https://doi.org/10.1051/epj-conf/201715702004). g See the author list of Litaudon et al 2017 (https://doi.org/10.1088/1741-4326/aa5e28).
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | DE-AC05-00OR22725 |
| Horizon 2020 Framework Programme | |
| H2020 Euratom | 633053 |
Keywords
- Fusion fuel isotopic content
- ITER
- JET DTE2
- JET ITER-like wall
- Magnetic fusion energy
- Residual gas analysis
