Ghidersa, Bradut‐Eugen

Gonfiotti, Bruno

Ionescu‐Bujor, Mihaela

Jin, Xue Zhou

Stieglitz, Robert

English

Ghidersa, Bradut-Eugen

Ionescu-Bujor, Mihaela

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz Association31st Symposium on Fusion TechnologySeptember 20 – 25, 2020, Virtual EditionOutcomes of the experimental campaignThe experimental campaign provided a robust set of experimental data that iscurrently used to validate system codes RELAP5-3D and MELCOR 1.8.6 forfusion. The different tests also demonstrate the quick temperature rise in case ofdemanding LOFAs (0% and 5% scenarios) that might hamper the integrity of thesystem. In the full LOFA scenario, flows in reverse direction through somechannels were established (plateau between 16 and 20 s in the 0% LOFA graphbelow). The figure below shows the outlet coolant temperature from channels 3and 4 (both under heat load and LOFA) for several repetitions (tests) of thedifferent scenarios at 300 kW/m2.Incorporation of data in design and safety analysisOne of the aims of the experimental campaign was to provide data and createpractical experience to support the design and safety analyses. Although, duringthe development (design of the campaign, execution, and post-test analysis) thedesign of the HCPB FW changed and the 180° bend in the channels was removedand straight channels with artificial roughness are used instead. The bend has adirect influence on the flow field, which is no more representative of the currentFW design. Hence, these data can’t be directly used in support of the design andsafety analysis, but these remarks can be made:• A quick temperature rise on the FW surface is established in case of fullLOFA. A quick reaction of the plasma shutdown system is needed to avoiddamages that might hamper the integrity of the blanket.• Even if due to the experimental set-up, the establishment of reverse flows insome channels in the actual FW design can’t be excluded a priori. Localizedthermal stresses can be then created that might cause local damaging.• The practical experience gained through the campaign remains relevant forthe planned experimental activities.• The execution of pre-test numerical analysis in support of experimentalcampaigns is a successful strategy. The execution of post-test analysis openalso room for the validation of numerical codes.Q&A sessionQ&A session will be held on Skype on Monday 21st Sept. at 17:00. You can findthe corresponding author on Skype under the name: “Bruno Gonfiotti (KIT-INR)” orthrough the following link: https://join.skype.com/invite/o9lTs2M0nfOgAn attempt to incorporate experimental data in the Breeding Blanket First Wall design and safety analysisBruno Gonfiotti, B. Ghidersa, X. Z. Jin, M. Ionescu-Bujor, R. StieglitzThis work has been carried out within the framework of theEUROfusion Consortium and has received funding from the Euratomresearch and training programme 2014-2018 and 2019-2020 undergrant agreement No 633053. The views and opinions expressedherein do not necessarily reflect those of the European Commission.”GoalIncorporate the results of an experimental campaign and the lesson learnt from itin the Breeding Blanket First Wall design and safety analysis. The campaigninvestigated the behavior of a Helium Cooled Pebble Bed (HCPB) First Wall (FW)mock-up under Loss of Flow Accident (LOFA) conditions.First Wall mock-up and preliminary experimental setupThe First Wall (FW) mock-up is a P92 steel plate crossed by 10 channelscharacterized by a 180° bend. It was developed as part of a study concerningvarious fabrication path for a blanket FW. The mock-up was installed in the KITHELOKA-HP facility and heated-up by means of an electron beam gun on an areaof 0.58x0.16 m2 placed in the middle of the plate. Because of its single-loopnature, the mock-up had to be installed to two distinct distribution manifolds (bothat the inlet and at the outlet). The LOFA condition have been reproduced closing avalve in one of the outlet manifolds. The cooling strategy (co-current or counter-current) was initially left as an open issue as well as the geometry and the layoutof the pipes connecting the mock-up and the manifolds.Preliminary numerical analysisANSYS calculations suggested the adoption of counter-current flow to have amore homogeneous distribution of the temperature (see figure below). RELAP5-3D calculations cleared the control strategy of the valves reproducing the LOFAand the duration of the tests to avoid damages to the mock-up itself.The experimental campaignThe experimental campaign was performed investigating two different heat loads:300 and 330 kW/m2. For each heat load 6 LOFA scenarios were investigated: 60%of the flow area of the outlet valve left open, 40%, 20%, 10%, 5%, and 0% (valvefully closed – also called full LOFA).

An attempt to incorporate experimental data in the Breeding Blanket First Wall design and safety analysis

https://publikationen.bibliothek.kit.edu/1000124254/89284338

An attempt to incorporate experimental data in the Breeding Blanket First Wall design and safety analysis

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