S.M. Kaye J.W. Connor C.M. Roach
In this paper, we review the confinement and transport properties observed and predicted in low aspect ratio tokamaks, or spherical tokamaks (STs), which can depart significantly from those observed at higher aspect ratio. In particular, thermal energy confinement scalings show a strong, near linear dependence of energy confinement time on toroidal…
Preprint PurchaseNick Walkden Fabio Riva James Harrison Fulvio Militello Tom Farley John Omotani
Fusion power plant designs based on magnetic confinement, such as the tokamak design, offer a promising route to sustainable fusion power but require robust exhaust solutions capable of tolerating intense heat and particle fluxes from the plasma to material surfaces. Turbulent plasma transport in the divertor volume – the region where the plasma-…
Preprint PublishedArunodaya Bhattacharya Steven J Zinkle Jean Henry Samara M Levine Philip D Edmondson MarkRGilbert Hiroyasu Tanigawa Charles E Kessel
Reduced activation ferritic martensitic (RAFM) and oxide dispersion strengthened (ODS) steels are the most promising candidates for fusion first-wall/blanket (FW/B) structures. The performance of these steels will deteriorate during service due to neutron damage and transmutation-induced gases, such as helium/hydrogen, at elevated operating tempera…
Preprint PublishedC. Vincent S. Allan G. Naylor R. Stephen S. Bray A. Thornton A. Kirk
Neutron flux measurements are important in fusion devices for both safety requirements and physics studies. A newsystem has been built for the Mega Amp Spherical Tokamak Upgrade (MAST Upgrade) that provides neutron count,DC and Campbell mode measurements for a 1μsperiod at 1 MHz. The acquisition system uses a Red Pitaya board tosample current from…
Preprint PurchaseSehila M. Gonzalez de Vicente Nicholas A. Smith Laila El-Guebaly Sergio Ciattaglia Luigi Di Pace Mark Gilbert Robert Mandoki Sandrine Rosanvallon Youji Someya Kenji Tobita David Torcy
In the absence of official standards and guidelines for nuclear fusion plants, fusion designers adopted, as far as possible, well-established standards for fission-based nuclear power plants (NPPs). This often implies interpretation and/or extrapolation, due to differences in structures, systems and components, materials, safety mitigation systems,…
Preprint PublishedN. VIANELLO N. WALKDEN M. DUNNE B. LOMANOWSKI E. WOLFRUM C. TSUI A. STAGNI M. GRIENER B. TAL T. EICH D. REFY D. BRIDA O. FÈVRIER M. AGOSTINI H. DE OLIVEIRA S. ALEIFERIS M. BERNERT J. BOEDO M. BRIX D. CARRALERO I. CARVALHO L. FRASSINETTI C. GIROUD A. HAKOLA A. HUBER J. KARHUNEN A. KARPUSHOV7 B. LABIT A. MEIGS V. NAULIN T. PEREIRA C. PEREZ VON THUN H. REIMERDES C. THEILER the ASDEXUpgrade Team the TCV team the EUROfusion MST1 Team and the JET Contributors
The evolution of SOL density profiles and fluctuations have been studied at different recycling levels in 3 different tokamaks, ASDEXUpgrade, TCV and JET, all operated in HMode. In all devices we clearly observe an increase of far SOL efolding length at high …
Preprint PublishedO.Crofts A.Loving M.Torrance S.Budden B.Drumm T.Tremethick D.Chauvin M.Siuko W.Brace V.Milushev M.Mittwollen T.Lehmann F.Rauscher G.Fischer P.Pagani Y.Wang C.Baars A.Vale
During the EU DEMO Pre-Concept Design Phase, the remote maintenance team developed maintenance strategies and systems to meet the evolving plant maintenance requirements. These were constrained by the proposed tokamak architecture and the challenging environments but considered a range of port layouts and handling system designs. The design‑d…
Preprint PurchaseT. E. G. Nicholas J. Omotani F. Riva F. Militello B. Dudson
There exists a large body of previous work using reduced two-dimensional models of the SOL, which model fluctuations in the drift-plane but approximate parallel transport with effective loss terms. Full size three-dimensional simulations of SOL turbulence in experimental geometries are now possible, but are far more computationally expensive than …
Preprint PublishedE. Berger I. Pusztai S.L. Newton M. Hoppe O. Vallhagen A. Fil T. Fülöp
Understanding generation and mitigation of runaway electrons in disruptions is important for the safe operation of future tokamaks. In this paper we investigate runaway dynamics in reactor-scale spherical tokamaks. We study both the severity of runaway generation during unmitigated disruptions, as well as the effect that typical mitigation schem…
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