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Mascari, F.*; Bersano, A.*; Woods, B. G.*; Reyes, J. N.*; Welter, K.*; 中村 秀夫; D'Auria, F.*
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03
Safety analyses have a key role for designing the mitigation strategies and for a safety review process, which are carried-out with best-estimate thermal-hydraulic system codes. Small Modular Reactors (SMRs) adopting passive mitigation strategies under development are characterized by some common features with the current reactors and by other features typical of their designs. While many of Natural Circulation (NC) have been studied, further analyses are necessary to confirm the code capability against experimental data representative of SMR phenomenology. Though different scaling methods have been developed, distortions are unavoidable in the experimental facility design. Then, scaled-down facilities are limited in scaling-up capabilities, which may affect the capability of the code to predict full-scale behavior. Therefore, in a V&V process, uncertainty related to the code scaling-up capability is still an open issue. Since the OSU-MASLWR is scaled in volume and height, this paper aims to assess the scaling-up capability of the OSU-MASLWR Reactor Pressure Vessel nodalization against NC phenomenology typical of SMR, having the OSU-MASLWR-002 single phase NC data as a base. This may give some first insights about the TRACE scaling-up capability against single-phase NC in integral type configuration.
Bierwage, A.; Di Troia, C.*; Briguglio, S.*; Vlad, G.*
Computer Physics Communications, 183(5), p.1107 - 1123, 2012/05
被引用回数：11 パーセンタイル：55.81(Computer Science, Interdisciplinary Applications)This work deals with the initial loading of phase space markers for global gyrokinetic particle-in-cell (PIC) simulations of plasmas that are magnetically confined in a toroidally axisymmetric configuration. A method is presented, which allows to prepare a marker distribution that is independent of time. This is achieved by loading markers on the toroidal surfaces of unperturbed guiding center orbits, where they are distributed uniformly in time. This allows to initialize global PIC codes with an accurate equilibrium distribution function and facilitates simulations with minimal noise-signal correlation. The concrete problem considered is the representation of energetic ions in tokamaks, which are characterized by large drifts across magnetic surfaces.
Gaio, E.*; Novello, L.*; Piovan, R.*; 島田 勝弘; 寺門 恒久; 栗原 研一; 松川 誠
Fusion Engineering and Design, 84(2-6), p.804 - 809, 2009/06
被引用回数：19 パーセンタイル：76.21(Nuclear Science & Technology)コイルクエンチ時に超電導コイルの蓄積エネルギーを高速に取り除かなければならないJT-60SAのクエンチ保護回路の概念設計について発表を行う。クエンチ保護回路の主要部は、高速にコイル消磁を行うためにコイル電流を抵抗に転流させる直流電流スイッチで構成される。本発表では、機械スイッチと半導体スイッチの一つであるIGCT(Integrated Gate Commutated Thyristor)の並列接続で構成されたハイブリッド型電流スイッチを提案し、検討した結果について述べる。また、クエンチ保護回路の主要部のほかに、電流スイッチで電流遮断失敗した場合のバックアップ回路として直列にパイロブレーカーを接続する。提案するハイブリッド型クエンチ保護回路は、半導体スイッチの特徴である高速遮断性能とメンテナンスフリーの利点と機械スイッチの特徴である低損失の利点の両方を併せ持つ回路構成となる。
Bierwage, A.; Di Troia, C.*; Zonca, F.*
no journal, ,
A new software tool is presented which allows to initialize particle simulations of magnetically confined plasmas with an arbitrary particle distribution function. Besides facilitating simulations with (in principle) arbitrary spatial localization and velocity-space anisotropicity, the distinguishing feature of this tool is that it allows to construct an exact kinetic equilibrium for cases where magnetic drift orbits play an important role. One timely example is the interaction between energetic ions and magnetohydrodynamic modes in tokamaks used to study burning plasma conditions. In such cases, input data that consists of measurable (and physically meaningful) quantities is not sufficient to uniquely describe the equilibrium distribution function. The additional information required to design an exact equilibrium from incomplete input data is obtained by pre-computing the unperturbed drift orbits of all phase-space samples. Marker particles are distributed along these trajectories (excluding loss orbits) and appropriate weight factors are assigned. First simulation results with the new marker loading module will be presented as they become available.
Garzotti, L.*; Barbato, E.*; Garcia, J.*; Romanelli, M.*; Stankiewicz, R.*; 林 伸彦; 吉田 麻衣子
no journal, ,
JT-60SA scenarios have been simulated with different codes and transport models. Aim of the simulations was to assess stationary conditions estimated with 0-dimensional codes and provide a profile database for further physics studies. Three scenarios considered are standard H-mode, hybrid, advanced steady-state. Codes deployed are ASTRA, CRONOS, JINTRAC. Core transport models used are TGLF (CRONOS), CDBM (CRONOS), GLF23 (ASTRA, CRONOS), Bohm/gyro-Bohm (ASTRA, JINTRAC). Edge transport barrier models are continuous ELMs (JINTRAC), Cordey scaling + EPED1 (CRONOS). Boundary conditions are imposed at separatrix (CRONOS JINTRAC) or top of the pedestal (ASTRA). Fully predictive simulations of current density, ion density (CRONOS and JINTRAC, density not evolved in ASTRA), ion and electron temperature. No rotation. Equilibrium solver SPIDER or three moments (ASTRA), HELENA (CRONOS) and ESCO (JINTRAC). Results are close to those obtained with zero-dimensional codes. Detail of the profiles differ from code to code. Electron and ion temperatures assumed in zero-dimensional calculations seem to be optimistic for most scenarios. For all scenarios normalized pedestal pressure seems to be below MHD stability limit. Further analysis of pedestal stability is required. Analysis of time dependent scenarios (density and current ramp up and down) is planned.
Tommasi, G. D.*; Farthing, J.*; Joffrin, E.*; Vega, J.*; Vitale, V.*; Clement, S.*; Sartori, F.*; 久保 博孝; 中島 徳嘉*; 小関 隆久
no journal, ,
ITERの遠隔実験センターは、国際核融合エネルギー研究センターの事業の一つである。遠隔実験センターの目的は、研究者がITER実験に遠隔地から参加できることである。それには、装置状態情報及び実験データを実時間で受け取り、制御室と交信できることが含まれる。本発表では、まず遠隔実験センター事業の最近の状況について概要を述べた後に、欧州トカマクの協力によって行われる遠隔実験のデモンストレーションに対する提案を中心に述べる。最後に、デモンストレーションで想定される実施計画について議論する。
Tommasi, G. D.*; Farthing, J.*; Joffrin, E.*; 久保 博孝; Vitale, V.*; Clement, S.*; Sartori, F.*; 中島 徳嘉*; 小関 隆久
no journal, ,
ITERの遠隔実験センターは、国際核融合エネルギー研究センターの事業の一つである。遠隔実験センターの目的は、研究者がITER実験に遠隔地から参加できることである。それには、装置状態情報及び実験データを実時間で受け取り、制御室と交信できることが含まれる。本発表では、まず遠隔実験センター事業の最近の状況について概要を述べた後に、欧州トカマクの協力によって行われる遠隔実験のデモンストレーションに対する提案を中心に述べる。最後に、デモンストレーションで想定される実施計画について議論する。
