Arredondo, R.

Pomella Lobo, T.

Schmid, K.

Schwarz-Selinger, T.

Theodorou, A.

English

KITopen

This work has been carried out within the framework of the EUROfusion Consortium, funded bythe European Union via the Euratom Research and Training Programme (Grant Agreement No101052200 — EUROfusion). Views and opinions expressed are however those of the author(s)only and do not necessarily reflect those of the European Union or the European Commission.Neither the European Union nor the European Commission can be held responsible for them.IMPLICATIONS OF T LOSS IN FIRST WALL ARMOR AND STRUCTURAL MATERIALS ON T-SELF-SUFFICIENCY IN FUTURE BURNING FUSION DEVICESK. Schmid1, T. Schwarz-Selinger1, R. Arredondo1, A. Theodorou1, T. Pomella Lobo21Max-Planck-Institut für Plasmaphysik2Institute for Neutron Physics and Reactor Technology (KIT)*Corresponding author:Klaus.Schmid@ipp.mpg.dePoster No.: TEC-MTL-1971IAEA-FEC 2023 London❖ Repeat T-self-sufficiency estimates from [1] including T-wall-sinks due to neutrondamage with refined and experimentally validated material data bases❖ Results are qualitatively similar: It takes up to 6 fpy to sufficiently saturate trapswith T based on simple T-self-sufficiency model❖ Hot wall (HCPB) with thin W layer performs best❖ Isotope exchange makes pre-saturating defects with D useless➢ Possible solution: avoid the need for saturating n-damage generated traps in thewall by increasing recycling❑ E.g. Castellated wall surface with increased out-diffusion through side faces❑ E.g. Open porosity by He-pre-irradiation [9]CONCLUSION❖ Future fusion reactors must breed enough T to sustain themselves and providestart up fuel for additional reactors❖ T production is governed by “Tritium Breeding Ratio” TBR❖ Displacement damage by fast fusion neutrons increases retention by orders ofmagnitude in W and EUROFER❖ TBR is calculated including various sources and sinks for T➢ Ignoring T trapping in n-damage defects underestimates first wall T sink❖ Using current experimental data on trapping in displacement damaged W andEUROFER:➢ Compute T-loss probability in first wall➢ Compare to simple T-self-sufficiency requirements model➢ Derive time too T-self-sufficiency as first wall traps are saturated➢ Investigate inefficiency of pre-saturating wall with D due to isotopeexchange❖ Repeat simulations from [1] with refined, validated material data baseABSTRACT❖ Compute 𝑝𝑡𝑟𝑎𝑝 using TESSIM-X for a range of parameters➢ Vary cooling concepts /temperatures: HCPB vs WCLL➢ Vary particle influx➢ Vary boundary conditions❖ Compare to 𝑝𝐶𝑟𝑖𝑡 from simple T-self-sufficiency model➢ Depending on parameters it takes up to 6 fpy to reachT-self-sufficiency➢ 𝑝𝑡𝑟𝑎𝑝 time evolution is dominated by W-armor layer➢ Thin W-armor and hot (HCPB) wall reachT-self-sufficiency fastestT-SELF-SUFFICIENCY❖Plasma:➢E = 500eV➢𝜞𝑫+𝑻 = 𝟏𝑬𝟏𝟖, 𝟏𝑬𝟏𝟗, 𝟏𝑬𝟐𝟎 𝒎−𝟐𝒔−𝟏➢D:T = 1:1CoolantSIMULATION GEOMETRY❖ Re-fit data from “M. Pečovnik et al Nucl. Fusion 60 (2020)036024”➢ Produce single set of fit parameters for alltemperatures➢ Only vary trap concentration with temperature→ Experimentally verified set of transport parameters fordisplacement damaged W at 300 to 800KMODEL PARAMETERS FOR W[1] R. Arredondo, et al., Nuclear Materials and Energy 28 (2021) p. 101039[2]  K. Schmid, et al., Nuclear Materials and Energy (2023) Vol. 34 p. 101341[3]  K. Schmid, et al., Nuclear Materials and Energy (2023) Vol. 36 p. 101494[4] E. Martelli, et al., Int. J. Energy Res. 42 (2018) . 27[5] F. Hernández, et al., Fusion Eng. Des. 124 (2017) . 882[6] K. Schmid, et al., J. Appl. Phys. 116 (2014) 134901[7] K. Schmid, M. Zibrov Nucl. Fusion 61 (2021) 086008[8] B. Deng et al, Nucl. Fusion 51 (2011) 073041[9] Miyamoto M. et al. 2015 J. Nucl. Mater. 463 333❖ Must breed more T than is lost in wall for given TBRSIMPLE T-SELF-SUFFICIENCY MODEL❖ D-retention data of displacement damaged EUROFER from [2]➢ Experiment suggests strong increase in retention with displacement damage➢ Displacement damage created at room temperature anneals at ~600K➢ Intrinsic defects do not anneal up to 800K❖ Transport parameters for D in EUROFER from [3]➢ Modeling suggests very weak traps 0.9 and 1.1 eV de-trapping energy➢ Strong surface limit for gas phase uptake❖TESSIM-X fit to available experimental data on damage EUROFER:MODEL PARAMETERS FOR EUROFER673 to 792K663 to 783K612 to 683KW-amourEUROFER➢ Use 800K data for HCPB➢ Use 600K data for WCLL➢ Damage EUROFER at 300 K➢ „Gentle“ D-loading at 370 K➢ TDS & NRA to detect D-containing defects❖ More experiments are needed for EUROFER→ Displacement damage at high T Γ𝐼𝑛𝑗𝑒𝑐𝑡 = Γ𝐵𝑢𝑟𝑛 + 𝑝𝑡𝑟𝑎𝑝 𝑡 Γ𝑊𝑎𝑙Γ𝐵𝑢𝑟𝑛 = 𝑝𝐵𝑢𝑟𝑛 𝜂𝑃𝑒𝑙𝑙𝑒𝑡Γ𝐼𝑛𝑗𝑒𝑐𝑡 + 𝜂𝑅𝑒𝑐𝑦𝑐𝑙𝑒Γ𝑊𝑎𝑙𝑙 × 1 − 𝑝𝑡𝑟𝑎𝑝 𝑡Γ𝐵𝑟𝑒𝑑 = 𝑇𝐵𝑅 − 1 Γ𝐵𝑢𝑟𝑛Γ𝑇𝑟𝑎𝑝 = 𝑝𝑡𝑟𝑎𝑝 𝑡 Γ𝑊𝑎𝑙 න0∆𝑡Γ𝑇𝑟𝑎𝑝 𝑡 𝑑𝑡 < න0∆𝑡Γ𝐵𝑟𝑒𝑑 𝑡 𝑑𝑡𝑝𝑡𝑟𝑎𝑝 =0׬∆𝑡𝑝𝑡𝑟𝑎𝑝 𝑡 𝑑𝑡∆𝑡< 𝑝𝐶𝑟𝑖𝑡 =11 +1𝜂𝑅𝑒𝑐𝑦𝑐𝑙𝑒 𝑝𝐵𝑢𝑟𝑛 1 − 𝑇𝐵𝑅−𝜂𝑃𝑒𝑙𝑙𝑒𝑡𝜂𝑅𝑒𝑐𝑦𝑐𝑙𝑒𝑇𝐵𝑅𝑇𝐵𝑅 − 1𝟎׬∆𝒕𝒑𝒕𝒓𝒂𝒑 𝒕 𝒅𝒕∆𝒕= Computed by TESSIM-X→ Compensate T loss by burn and wall sink→ Burn T from pellets and recycling (i.e. non trapped T)→ Breed more T from burn than is lost in wall sink ❖ Model simultaneous transport of D, T through W layer onEUROFER➢ Mimic HCPB[5] and WCLL[4] blanket concepts➢ W armor layer on EUROFER structural materialconnected to coolant➢ Blanket concepts differ in amor thickness andthus T-gradients❖ Simulations use TESSIM-X code [6,7] in 1D linear geometry❖ Diffusion limited boundary conditions on W inlet side❖ Diffusion or surface limited boundary conditions onEUROFER/coolant sideSIMULATION SETUP❖ Investigate influence of pre-saturating wall with D➢ Expose wall to 100% D➢ After break through to coolant switch to D:T = 1:1➢ Compare retention and 𝒑𝒕𝒓𝒂𝒑 to non pre-saturated case❖ Pre-saturating with D leads to slightly faster break through to coolant❖ Isotope exchange is very efficient at these high temperatures➢ 𝑝𝑡𝑟𝑎𝑝 is unaffected by pre-saturating wall with D➢ T-retention is unaffected by pre-saturating wall with D→ Sponge effect [8] does not work due to isotope exchangeISOTOPE EXCHANGE0.8 to 2 mm 3 to 4 mm❑ Damage W at 300 to 800 K❑ Sequential loading with 300eV D at 450K❑ TDS & NRA to detect D-containing defects

Implications of T loss in first wall armor and structural materials on t-self-sufficiency in future burning fusion devices

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Implications of T loss in first wall armor and structural materials on t-self-sufficiency in future burning fusion devices

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