平成26年度研究開発・評価報告書 評価課題「核融合研究開発」(事後評価)

核融合研究開発部門

JAEA-Evaluation 2016-001, 128 Pages, 2016/03

JAEA-Evaluation-2016-001.pdf:33.25MB

日本原子力研究開発機構(以下、「原子力機構」という)は、「国の研究開発評価に関する大綱的指針」(平成20年10月31日内閣総理大臣決定)及びこの大綱的指針を受けて作成された「文部科学省における研究及び開発に関する評価の指針」(平成21年2月17日文部科学大臣決定)、並びに原子力機構の「研究開発課題評価実施規定」(平成17年10月1日制定、平成21年8月19日改正)等に基づき、「核融合エネルギーを取り出す技術システムの研究開発」に関する事後評価を核融合研究開発・評価委員会に諮問した。これを受けて、核融合研究開発・評価委員会は、原子力機構から提出された平成22年4月から平成26年11月までの核融合研究開発部門の運営ならびに核融合研究開発の実施状況に関する説明資料の検討、及び核融合研究開発部門長による口頭発表と副部門長も交えての質疑応答・意見交換を行った。本報告書は、核融合研究開発・評価委員会より提出された事後評価の内容、並びに、委員会による指摘事項とそれに対する措置を取りまとめたものである。

幅広いアプローチ活動だより,58

星野 一生; 松永 剛; 奥村 義和

プラズマ・核融合学会誌, 91(12), p.802 - 803, 2015/12

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2015_12/jspf2015_12-802.pdf

幅広いアプローチ活動だより(58)では、第17回IFERC事業委員会及び第16回IFMIF/EVEDA事業委員会の開催、サテライト・トカマク(JT-60SA)計画の進展に関して報告している。IFERC事業委員会には、メゾニエ議長をはじめ、日欧の委員,専門家,事業チーム等、33名が参加し、各活動の状況報告、2016年のIFERC事業の作業計画案、事業計画の改訂案等を審議し、BA運営委員会に対する技術的な勧告をまとめた。IFMIF/EVEDA事業委員会には、高津議長をはじめ、日欧の委員、専門家、事業チーム等、27名が参加し、各活動の状況報告、IFMIF/EVEDA事業の2016年の作業計画案、事業計画の改訂案等を審議し、新たな事業計画案をBA運営委員会が承認することを勧告した。サテライト・トカマク計画では、トロイダル磁場コイル等の組立用旋回クレーンが設置されるとともに、340度まで組立の進んだ真空容器の拘束治具の解体が進められた。また、トロイダル磁場コイル用高温超伝導電流リード6本が欧州から完納された。これら、BA活動における主要な出来事を国内コミュニティーに対して情報発信する。

幅広いアプローチ活動だより,56

星野 一生; 松永 剛; 奥村 義和

プラズマ・核融合学会誌, 91(8), p.561 - 562, 2015/08

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2015_08/jspf2015_08-561.pdf

幅広いアプローチ活動便り(56)では、国際核融合エネルギー研究センターサイトにおける原型炉R&Dのための共同研究棟の新築工事、IFMIF原型加速器の進展、サテライト・トカマク(JT-60SA)計画の進展に関して報告している。共同研究棟は、残りのBA活動期間に原型炉R&Dに関する研究開発の一部の課題を行う新たな場所として工事を進めており、主に材料評価のための実験室・材料試験室と金属ベリリウムの取り扱いのためのBe製造室で構成されている。IFMIF原型加速器では、改修やインターロックの試運転等を終え、4月に定格の陽子ビームの連続生成に成功、引き続き、放射線管理区域の設定後、7月には重水素イオンビームの生成に成功した。サテライト・トカマク計画では、世界最大級のヘリウム冷凍機及びHeバッファータンクの据え付けを完了した。また、第4回「JT-60SA日欧研究調整会議」を開催し、JT-60SAリサーチプラン、JT-60SA実験提案に向けた課題等について議論を行った。これら、BA活動における主要な出来事を国内コミュニティーに対して情報発信する。

Advance in integrated modelling towards prediction and control of JT-60SA plasmas

林 伸彦; 本多 充; 白石 淳也; 宮田 良明; 若月 琢馬; 星野 一生; 藤間 光徳; 鈴木 隆博; 浦野 創; 清水 勝宏; et al.

Europhysics Conference Abstracts (Internet), 39E, p.P5.145_1 - P5.145_4, 2015/06

http://ocs.ciemat.es/EPS2015PAP/pdf/P5.145.pdf

Towards prediction and control of JT-60SA plasmas, we are developing codes/models which can describe physics/engineering factors, and integrating them to one code TOPICS. Physics modelling: Coupling with MINERVA/RWMaC code showed that MHD equilibrium variation by centrifugal force largely affects RWM stability and the toroidal rotation shear stabilizes RWM. Coupling with OFMC code for NB torques, 3D MHD equilibrium code VMEC and drift-kinetic code FORTEC-3D for NTV torque, and toroidal momentum boundary model, predicted the core rotation of 2% of Alfvn speed for a ITER hydrogen L-mode plasma. Coupling with core impurity transport code IMPACT showed the accumulation of Ar seeded to reduce the divertor heat load is so mild that plasma performance can be recovered by additional heating in JT-60SA steady-state (SS) scenario. Simulations coupled with MARG2D code showed that plasma current can be ramped-up to reach 3 with MHD modes stabilized by ideal wall and with no additional flux consumption of central solenoid in JT-60SA. Engineering modelling: Coupling with integrated real-time controller showed that simultaneous control of and is possible at 4 in JT-60SA SS scenarios. MHD equilibrium control simulator MECS demonstrated equilibrium control during heating phase and collapse induced events within power supply capability of PF coils in JT-60SA.

Simulation of plasma current ramp-up with reduced magnetic flux consumption in JT-60SA

若月 琢馬; 鈴木 隆博; 林 伸彦; 白石 淳也; 井手 俊介; 高瀬 雄一*

Plasma Physics and Controlled Fusion, 57(6), p.065005_1 - 065005_12, 2015/06

https://doi.org/10.1088/0741-3335/57/6/065005

Current ramp-up with reduced central solenoid (CS) flux consumption in JT-60SA has been investigated using an integrated modeling code suite (TOPICS) with a turbulent model (CDBM). The plasma current can be ramped-up from 0.6 MA to 2.1 MA with no additional CS flux consumption if the plasma current is overdriven by neutral-beam-driven and bootstrap current. The time duration required for the current ramp-up without CS flux consumption becomes as long as 150s. In order to achieve the current overdrive condition from 0.6 MA, the current drive by a lower energy neutral beam (85 keV) is effective. A higher energy neutral beam (500 keV) cannot be utilized in this early phase due to large shine through loss, while it can be effectively utilized in the later phase. Therefore, the main current driver should be switched from the lower energy neutral beam to the higher energy neutral beam during the current ramp-up phase. As a result of an intensive auxiliary heating needed to overdrive the plasma current, plasma beta becomes high. Ideal MHD stabilities of such high beta plasmas have been investigated using a linear ideal MHD stability analysis code (MARG2D). External kink modes can be stabilized in most of the time during the current ramp-up if there is a perfectly conducting wall at the location of the stabilizing plate and the vacuum vessel of JT-60SA and the plasma has a broader pressure profile.

Assessment of operational space for long-pulse scenarios in ITER

Polevoi, A. R.*; Loarte, A.*; 林 伸彦; Kim, H. S.*; Kim, S. H.*; Koechl, F.*; Kukushkin, A. S.*; Leonov, V. M.*; Medvedev, S. Yu.*; 村上 匡且*; et al.

Nuclear Fusion, 55(6), p.063019_1 - 063019_8, 2015/05

https://doi.org/10.1088/0029-5515/55/6/063019

The operational space (-) for long pulse scenarios of ITER was assessed by 1.5D core transport modelling with pedestal parameters predicted by the EPED1 code. The analyses include the majority of transport models presently used for interpretation of experiments and ITER predictions. The EPED1 code was modified to take into account boundary conditions predicted by SOLPS for ITER. In contrast with standard EPED1 assumptions, EPED1 with the SOLPS boundary conditions predicts no degradation of the pedestal pressure as density is reduced. Lowering the plasma density to 5-6 10 m leads to an increased plasma temperature (similar pedestal pressure), which reduces the loop voltage and increases the duration of the burn phase to 1000 s with Q 5 for 13 MA at moderate normalised pressure ( 2). These ITER plasmas require the same level of additional heating power as the reference Q = 10 inductive scenario at 15 MA. However, unlike the "hybrid" scenarios considered previously, these H-mode plasmas do not require specially shaped q profiles nor improved confinement in the core for the transport models considered in this study. Thus, these medium density H-mode plasma scenarios with 13 MA present an attractive alternative to hybrid scenarios to achieve ITER's long pulse Q 5 and deserve further analysis and experimental demonstration in present tokamaks.

Gyrokinetic analyses of core heat transport in JT-60U plasmas with different toroidal rotation direction

成田 絵美*; 本多 充; 林 伸彦; 浦野 創; 井手 俊介; 福田 武司*

Plasma and Fusion Research (Internet), 10, p.1403019_1 - 1403019_11, 2015/03

https://doi.org/10.1585/pfr.10.1403019

The internal transport barriers (ITBs) formed in the tokamak plasmas with the weak magnetic shear and the weak radial electric field shear are often observed and the pressure gradient at the ITB is not very steep. In such plasmas the electron temperature ITB is steeper for co toroidal rotation cases than that for counter rotation cases. Clarifying the relationship between the rotation direction and heat transport in the ITB region, dominant instabilities are examined by the flux-tube gyrokinetic code GS2 to show that the linear growth rates for the co and counter rotation cases are comparable in magnitude, but the counter case shows the more trapped electron mode like frequency. The ratio of the electron heat diffusivity to the ion's is higher for the counter-rotation case. The difference in the ratio between the two cases agrees with the experiment. Investigating the flow shear effect on reveals that its effect is not so large as to change the aforementioned tendency.

Fokker-Planck simulation of runaway electron generation in tokamak disruptions

奴賀 秀男; 松山 顕之; 矢木 雅敏; 福山 淳*

Plasma and Fusion Research (Internet), 10, p.1203006_1 - 1203006_2, 2015/01

https://doi.org/10.1585/pfr.10.1203006

The runaway electron generation during tokamak disruptions is investigated by kinetic simulations. Three dimensional Fokker-Planck simulations (2D in momentum space and 1D in radial direction) are carried out with various values of and the results are compared with the previous simulation results that use runaway generation rate derived by Conner and Hastie. From the simulation results, It is pointed out that the importance of the hot-tail effect for the description of the runaway electron generation mechanism with fast thermal quench.

Orbit-based analysis of resonant excitations of Alfvn waves in tokamaks

Bierwage, A.; 篠原 孝司

Physics of Plasmas, 21(11), p.112116_1 - 112116_21, 2014/11

https://doi.org/10.1063/1.4902519

The resonant interactions between shear Alfvn waves and resonant fast ions are analyzed numerically in realistic geometry and with a realistic particle distribution for a JT-60U plasma driven by two 400 keV N-NBs. In order to deal with the large magnetic drifts of the fast ions, a new orbit-based resonance analysis (ORA) method is developed and applied. The ORA method uses mappings that allows us to unify resonance conditions for trapped and passing particles, determine which harmonics are driven, and which orders of the resonance are involved. After analyzing the resonance conditions, the effects of wave-particle trapping, kinetic compression and linear resonance overlap are examined. Finally, we discuss the implications for frequency chirping, convective amplification, the long-time evolution of the system in the presence of a fast ion source, and for the interpretation of experimental observations.

Physics comparison and modelling of the JET and JT-60U core and edge; Towards JT-60SA predictions

Garcia, J.*; 林 伸彦; Baiocchi, B.*; Giruzzi, G.*; 本多 充; 井手 俊介; Maget, P.*; 成田 絵美*; Schneider, M.*; 浦野 創; et al.

Nuclear Fusion, 54(9), p.093010_1 - 093010_13, 2014/09

https://doi.org/10.1088/0029-5515/54/9/093010

Extensive physics analysis and modelling has been undertaken for the typical operational regimes of the tokamak devices JET and JT-60U with the aim of extrapolating present day experiments to JT-60SA, which shares important characteristics with both tokamaks. A series of representative discharges of two operational scenarios, H-mode and hybrid, have been used for this purpose. Predictive simulations of core turbulence, particle transport, current diffusion and pedestal pressure have been carried out with different combinations of models. The ability of the models for reproducing the experimental data is analysed and scenario calculations for JT-60SA are performed following an optimum set of models.