| 1. |
- Joffrin, E., et al.
(författare)
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Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall
- 2019
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 59:11
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Forskningsöversikt (refereegranskat)abstract
- For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.
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| 3. |
- Spirzewski, Michal, et al.
(författare)
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Uncertainty and sensitivity analysis of a phenomenological dryout model implemented in DARIA system code
- 2019
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Ingår i: Nuclear Engineering and Design. - : ELSEVIER SCIENCE SA. - 0029-5493 .- 1872-759X. ; 355
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Tidskriftsartikel (refereegranskat)abstract
- Uncertainties of numerical predictions play important role in assessment of safety margins in nuclear reactors. In this paper uncertainties of the predictions of the Hewitt-Govan model, which is used to determine the entrainment and deposition rates in phenomenological dryout model, are presented and discussed. Results of the global uncertainty analysis are shown in terms of trends of uncertainty values with respect to the pressure, mass flux and inlet subcooling. Regions of large and small uncertainties are identified and presented in a tabular form. Application of the global sensitivity analysis methods allowed to quantify the sources of uncertainties with high accuracy over large spectrum of experimental conditions. Since the present analysis required calculation of millions of cases, a dedicated fast-running three-field computational code called DARIA has been developed for that purpose. The analysis revealed that the uncertainties of dryout prediction are predominantly resulting from uncertainties of the coolant mass flow rate. The most obvious implication of the presented work is that, when applying the current methodology to predict dryout in rod bundles, the most important parameter, affecting the accuracy of predictions, is the distribution of coolant flow between sub-channels.
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