Bongiovi, G.

Häußler, A.

W7-X team

KITopen

Advancements in the HELIAS 5-B breeding blanket structural analysis   G. Bongiovía*, A. Häußlera and the W7-X team  aKarlsruhe Institute of Technology (KIT), Institute for Neutron Physics and Reactor Technology (INR), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, GERMANY  *Corresponding author: gaetano.bongiovi@kit.edu  Within the framework of EUROfusion consortium, the Work Package S2 aims at developing the HELIcal-axis Advanced Stellarator (HELIAS) as a possible long-term alternative to a tokamak DEMO. From the plasma physics standpoint the most promising concept is the HELIAS 5-B machine, a large 5 field period stellarator reactor directly extrapolated from Wendelstein 7-X. An intense research campaign has been launched at KIT in order to attain a preliminary design of the HELIAS 5-B breeding blanket (BB), taking into account as initial input the design experience acquired in the pre-conceptual design phase of the tokamak DEMO BB. To this end, the Helium-Cooled Pebble Bed (HCPB) breeding blanket concept has been considered, focusing on the investigation of the suitability of its main structural features to the stellarator geometry. Design requirements coming from the Remote Maintenance have been taken into account in order to orient the blanket segmentation and a more sophisticated assessment of the BB modules structural behavior has been performed. Attention has been also paid to the refinement of the numerical models so far adopted, investigating the impact of some assumptions on the obtained results. The achieved advancements in this HELIAS 5-B BB design are herewith presented and critically discussed, indicating a possible way for the follow up of this activity.   Keywords: HELIAS, stellarator, breeding blanket, thermomechanics, FEM analysis   Topic Category  Blanket Technology Presentation Preference □ Oral Presentation □ Poster Presentation  

Advancements in the HELIAS 5-B breeding blanket structural analysis

KIT – The Research University in the Helmholtz AssociationRing 8 Ring 1Karlsruhe Institute of TechnologyInstitute for Neutron Physics and Reactor Technology (INR)76344, Eggenstein-Leopoldshafen, Germanygaetano.bongiovi@kit.eduAdvancements in the HELIAS 5-B breeding blanketstructural analysisG. Bongioví1, A. Häußler1and the W7-X team1Karlsruhe Institute of Technology, INR, GermanyWithin the framework of EUROfusion consortium, the work package S2 aims at developing the HELIcal-axis Advanced Stellarator (HELIAS) as a possible long-termalternative to a tokamak DEMO. Researches are currently ongoing at KIT in order to attain a preliminary design of the HELIAS 5-B breeding blanket (BB), taking intoaccount as initial input the design experience acquired in the pre-conceptual design phase of the tokamak DEMO BB. To this end, the Helium-Cooled Pebble Bed (HCPB)and the Water Cooled Lithium Lead (WCLL) BB concepts have been considered, focusing on the investigation of the suitability of their main structural features to thestellarator geometry. In this regard, possible design constraints coming from the Remote Maintenance have to be fulfilled in order to better orient the blanketsegmentation. In the present work, a more sophisticated assessment of the BB modules structural behavior has been performed. Attention has been also paid to therefinement of the numerical models so far adopted, investigating the impact of the major assumptions, such as Vacuum Vessel temperature and equivalent Young’sModulus, on the obtained results. To this purpose, dedicated parametric assessment has been carried out and discussed in this work.ConclusionStructural calculations of the most representative BB rings have been performed adopting detailed homogenized FEM models. The quite promising outcomes encouragethe follow-up of the activity aimed at assessing a whole BB sector, which extends for 72 ° toroidally. Moreover, since a strong influence of the VV temperature on the BBstructural performances has been found out, the development of an attachment system devoted to connect BB and VV is crucial, together with the design of the BBsegments internal components, to more realistically assess the HELIAS 5-B BB thermomechanical behavior. Lastly, the RM-BB interface should be defined.The HELIAS 5-B Breeding Blanket (BB)Vacuum Vessel (VV)Ring 1(triangular shape section)Gap betweensegments = 20 mmGap betweenrings = 20 mmParametric study of the assumed equivalent Young´s Modulus12345Ring 1(triangular shape section)12345Ring 8(bean shape section)FW + WBZBSSVV inn VV shield VV outStructural materials:• AISI 316 for VV• Eurofer for BB components• W for FW armor (not consideredin the E sensitivity study)Ring 8(bean shape section)BB segmentsRing 1 [ton] Ring 8 [ton]HCPB WCLL HCPB WCLLRing 1 17.4 39.8 27.0 54.7Ring 2 18.6 43.8 25.2 56.0Ring 3 19.9 45.7 30.4 63.3Ring 4 18.8 50.0 17.8 47.4Ring 5 17.4 38.9 16.9 43.9Displacement along Z preventedSymmetry along local toroidal directionRing 1 minimum residual gaps [mm]E 1-2 2-3 3-4 4-5 5-110 % 3.097 8.916 4.757 6.003 5.50325 % 3.095 8.539 3.983 5.968 5.79250 % 3.005 8.105 3.209 5.992 5.39675 % 2.899 7.816 2.658 6.043 4.962100 % 2.799 7.609 2.222 6.103 4.584Ring 8 minimum residual gaps [mm]E 1-2 2-3 3-4 4-5 5-110 % 6.917 0.209 - 18.13 -25 % 6.901 -0.465 - 17.92 -50 % 6.391 -1.190 - 17.67 -75 % 5.943 -1.620 - 17.35 -100 % 5.575 -1.903 - 17.05 -Derived loading scenarios:• Less conservative (LC): E = 10 %• More conservative (MC): E = 100 %Ring 1 and Ring 8 structural performances – refined FEM modelsWhole 72° sector development and BB-VV attachments design FW slices BZ first sliceSliced components to imposea different temperature to each slide(3D discrete temperature profile)Assessed loading scenarios:• LC+Hot VV (E=10%, VV between 180 and 230 °C)• MC+Hot VV (E=100%, VV between 180 and 230 °C)• LC+Cold VV (E=10%, VV between 40 and 90 °C)• MC+Cold VV (E=100%, VV between 40 and 90 °C)Model Node Element TypeRing 1 ~1.1M ~4.0M Linear tetRing 8 ~1.4M ~5.0M Linear tetRing 1 – minimum residual gaps [mm]Segment LC+Cold VV LC+Hot VV ∆% MC+Cold VV MC+Hot VV ∆% ∆% Hot VV1-2 -5.938 4.294 172.3% -5.199 2.952 156.8% -31.2%2-3 -0.846 9.066 1171.4% -2.069 6.791 428.2% -25.1%3-4 -10.363 4.303 141.5% -11.192 1.510 113.5% -64.9%4-5 -3.715 8.031 316.2% -4.703 6.340 234.8% -21.1%5-1 -2.598 2.249 186.6% -1.390 2.203 258.5% -2.0%Ring 8 – minimum residual gaps [mm]Segment LC+Cold VV LC+Hot VV ∆% MC+Cold VV MC+Hot VV ∆% ∆% Hot VV1-2 -6.621 4.503 168.0% -6.264 2.388 138.1% -47.0%2-3 -12.514 1.037 108.3% -14.342 -2.976 79.2% -387.0%4-5 -1.168 7.635 753.4% -1.631 6.081 472.8% -20.3%Ring 1MC+Hot VV scenario – Segment 3-4Minimum residual gap = 1.510 mmTotal displacement [m]Total displacement [m]Ring 8MC+Hot VV scenario – Segment 2-3Overlapping• Equivalent densities assumed• Gravity load along Z direction• Uniform temperatures for FW, BZ, BSS and VV• Components mechanically tied

https://publikationen.bibliothek.kit.edu/1000091565/23446806

Advancements in the HELIAS 5-B breeding blanket structural analysis

Abstract

Similar works

Full text

Available Versions

KITopen

KITopen