WEKO3
アイテム
Investigation of divertor operation for Japanese DEMO under low density SOL and large power exhaust of Psep/R ~30 MW/m level
https://repo.qst.go.jp/records/79433
https://repo.qst.go.jp/records/79433d0ffea1a-31f5-4b47-a2e5-488eba6820ce
| Item type | 会議発表用資料 / Presentation(1) | |||||||
|---|---|---|---|---|---|---|---|---|
| 公開日 | 2020-03-15 | |||||||
| タイトル | ||||||||
| タイトル | Investigation of divertor operation for Japanese DEMO under low density SOL and large power exhaust of Psep/R ~30 MW/m level | |||||||
| 言語 | ||||||||
| 言語 | eng | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||||
| 資源タイプ | conference object | |||||||
| アクセス権 | ||||||||
| アクセス権 | metadata only access | |||||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||||
| 著者 |
Asakura, Nobuyuki
× Asakura, Nobuyuki× asakura× Homma, Yuuki× Kazuo, Hoshino (Graduate School of Science and Technology, Keio University)
WEKO
852458
× Sakamoto, Yoshiteru× Joint Special Design Team for Fusion DEMO, the× Asakura, Nobuyuki× Homma, Yuuki× Sakamoto, Yoshiteru |
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| 抄録 | ||||||||
| 内容記述タイプ | Abstract | |||||||
| 内容記述 | Power exhaust scenario for the feasible DEMO plasmas and the divertor design have been studied with a high priority in the steady-state Japanese (JA) DEMO with the fusion power of 1.5 GW-level and the major radius of 8 m-class. The power exhaust concept requires large power handling in the SOL and divertor, i.e. Psep~250 MW, and Psep/Rp~30 MWm-1 corresponds to 1.8 times larger than ITER. Moreover, the SOL plasma density (nesep) is expected to be relatively low, i.e. 2-3x1019 m-3, which corresponds to 1/3-1/2 of the pedestal density (nped ~6x1019 m-3) since nped is restricted by the Greenwald density limit (nGW = 6.6x1019 m-3). The long leg divertor (Ldiv = 1.6 m; 1.6 times longer than ITER) was proposed as a reference design. SONIC simulation with Ar impurity seeding demonstrated the peak heat load (qtarget) on the outer target was reduced to less than 10 MWm-2 under the partially detached condition with the large radiation fraction of fradsol+div = (Pradsol+Praddiv)/Psep ~0.8. Recently, operation of the plasma detachment and acceptable qtarget (<10 MWm-2) has been investigated under the severe conditions such as higher Psep ~300 MW or lower fradsol+div ~0.7. The peak qtarget was generally reduced with increasing nesep, because the detached plasma width was decreased and the peak Tediv and Tidiv at the attached plasma region were increased. The former case (higher Psep) is acceptable in the expecting nesep range of 2-3x1019 m-3, while the margin of the peak qtarget is reduced. On the other hand, the latter case (lower fradsol+div) requires operation in higher nesep 2.3x1019 m-3. At the same time, the peak Tediv and Tidiv were increased, which would enhance net erosion of the target. Investigation of the plasma diffusivity also started. Simulations with reducing both and D to half values, i.e. e =I = 0.5 m2s-1, D = 0.15 m2s-1, were performed for the three cases. Decay length of the parallel heat flux profile near the outer midplane separatrix (q//sol-OM) was decreased from the reference case (~1.9 mm), which is already narrow compared to 3.6 mm in the ITER simulation [2]. Peak qtarget values were increased for all reduced and D cases, and the reference and higher Psep cases were still acceptable, whereas higher nesep was preferred. On the other hand, for the lower fradsol+div case, peak qtarget <10 MWm-2 was not achieved in the operation range of the low nesep. Changes in the characteristics of the qtarget, Tediv and Tidiv profiles in the partially detached divertor are summarized. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | Third Technical Meeting on Divertor Concepts | |||||||
| 発表年月日 | ||||||||
| 日付 | 2019-11-06 | |||||||
| 日付タイプ | Issued | |||||||
