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山内 邦仁; 岡野 潤; 島田 勝弘; 大森 栄和; 寺門 恒久; 松川 誠; 小出 芳彦; 小林 和容; 池田 佳隆; 福本 雅弘; et al.
JAEA-Technology 2015-053, 36 Pages, 2016/03
JT-60SA計画は、日本の実施機関である原子力機構と欧州の実施機関であるFusion for Energy(F4E)が物納貢献により共同で進める国際事業である。欧州側では超伝導トロイダル磁場コイルの他、磁場コイル用電源の主要機器や極低温システム等を分担するが、F4Eの総括のもとで各国の指定研究機関が欧州のメーカーと契約し、その欧州のメーカーが那珂研での現地据付・調整試験までを行う。このため、原子力機構にとっては直接の契約がないにも係らず、欧州の作業員に対する作業管理や安全管理を行わなければならないという非常に難しい課題があった。本報告は、JT-60SA計画において、欧州の作業員による最初の那珂研での現地作業であるクエンチ保護回路の据付・調整試験を遂行するにあたって、欧州側との事前の密な交渉の結果として合意し、構築・実施した作業管理や安全管理の取組み、およびそれらをもとに完遂した欧州作業についてまとめたものである。これらの取組みの結果、欧州作業員によるクエンチ保護回路の現地据付調整作業を無事故で完遂させることができ、日欧双方にとって非常に大きな成果となった。
Novello, L.*; Cara, P.*; Coletti, A.*; Gaio, E.*; Maistrello, A.*; 松川 誠; Philipps, G.*; Tomarchio, V.*; 山内 邦仁
IEEE Transactions on Applied Superconductivity, 26(2), p.4700507_1 - 4700507_7, 2016/03
被引用回数:7 パーセンタイル:39.28(Engineering, Electrical & Electronic)The voltage transient appearing across and inside the toroidal field (TF) coils of JT-60SA in case of fast voltage variation, such as a safety discharge operated by the quench protection circuit (QPC), can be significantly high. In fact, the voltage distribution between coils and inside the winding can be not uniform during fast transient, being influenced by the presence of parasitic capacitances. A simplified electrical model of the TF coils has been developed to investigate this aspect. The obtained model has been used in conjunction with an electrical model of the TF circuit elements, including a simplified model of the QPC. The worst case in terms of transient voltage applied to the winding has been identified, corresponding to a fault to ground occurring just after QPC operation. It has been verified that the resulting voltage is largely inside the coil insulation capability defined by performed insulation voltage tests.
Maistrello, A.*; Gaio, E.*; Novello, L.*; 松川 誠; 山内 邦仁
Fusion Engineering and Design, 98-99, p.1109 - 1112, 2015/10
被引用回数:8 パーセンタイル:55.62(Nuclear Science & Technology)The interruption of high direct currents, required in fusion experiments, is a challenging task. Depending on the technology of the circuit breakers the resulting current derivative may be high, leading to dangerous transient overvoltages. This aspect has been analyzed for JT-60SA Quench Protection Circuits (QPC) devoted to the protection of superconducting coils. The QPC adopts edge technology solutions: a Hybrid mechanical-static Circuit Breaker (HCB) as main circuit breaker in series with a PyroBreaker (PB) as backup protection. Snubbers or clamp networks can be provided in parallel to the breakers to smooth the voltage waveform. Dedicated clamp networks for the HCB have been designed and tested during the qualification of the QPC prototypes. On the contrary, it was preferred not to apply any component in parallel to the PB, the ultimate protection, to avoid reducing its reliability. For PB a different approach has been worked out, based on the optimization of the layout of the QPC connections. Analyses have been performed to highlight the impact of different busbar routes on the transient voltage across the toroidal field coils at the PB intervention. The results indeed showed a variation of the peak voltage in between 30% of the maximum allowed value. The paper will present the analyses and will discuss the results.
Novello, L.*; Baulaigue, O.*; Coletti, A.*; Dumas, N.*; Ferro, A.*; Gaio, E.*; Lampasi, A.*; Maistrello, A.*; 松川 誠; 島田 勝弘; et al.
Fusion Engineering and Design, 98-99, p.1122 - 1126, 2015/10
被引用回数:16 パーセンタイル:78.98(Nuclear Science & Technology)JT-60SA, the superconducting tokamak under construction in Japan, will be equipped with a mix of new and reused Power Supplies (PS). Most of the new PS are procured by European Voluntary Contributors under the framework of Broader Approach agreement between F4E and JAEA. For the toroidal circuit, the 6 pulses ac/dc converter will be procured by CEA. It is rated 25.7 kA and 80 V dc, and will work in steady state condition. For the poloidal circuits the procurement of ten ac/dc converters, rated 20 kA and about 1 kV is shared between CEA and ENEA. They are 24 pulses four quadrant converters, with back to back thyristor bridges. Plasma initiation requires a fast variation of current in the Central Solenoids, obtained with the insertion of a settable resistor in series to the coils. This is achieved with the operation of four Switching Network Units procured by ENEA, producing up to 5 kV at the nominal 20 kA. The protection of superconducting magnets, both toroidal and poloidal, is assured by 13 Quench Protection Circuits procured by Consorzio RFX, rated 20 kA and 3.8 kV for poloidal QPCs and 25.7 kA and 2.8 kV for toroidal ones. The present status of the aforementioned PS is described in the paper: their detailed design has been completed and some systems have been already manufactured and tested.
Maistrello, A.*; Gaio, E.*; Ferro, A.*; Perna, M.*; Panizza, C.*; Soso, F.*; Novello, L.*; 松川 誠; 山内 邦仁
IEEE Transactions on Applied Superconductivity, 24(3), p.3801505_1 - 3801505_5, 2014/06
被引用回数:14 パーセンタイル:58.32(Engineering, Electrical & Electronic)This paper deals with the qualification process of the full scale prototypes of the Hybrid mechanical-static dc Circuit Breaker (HCB) for the Quench Protection Circuits (QPC) of the Toroidal Field (TF) and Poloidal Field (PF) superconducting coils of the Satellite Tokamak JT-60SA. The HCB developed for JT-60SA QPC is the first dc circuit breaker based on hybrid mechanical-static design at this level of power (25.7 kA - 1.93 kV, 20 kA - 3.8 kV). Special type tests have been designed to verify the performance of the device up to the nominal ratings and beyond, thus proving the suitability of the technology, the design margins and the reliability; the results of the most significant tests are presented and discussed. The qualification program also includes the validation of the electrical models developed during the design phase, which are described in the paper too.
Gaio, E.*; Maistrello, A.*; Barp, M.*; Perna, M.*; Coffetti, A.*; Soso, F.*; Novello, L.*; 松川 誠; 山内 邦仁
Fusion Engineering and Design, 88(6-8), p.563 - 567, 2013/10
被引用回数:15 パーセンタイル:74.05(Nuclear Science & Technology)This paper deals with the development, manufacturing and testing of the full scale prototype of the Quench Protection Circuit (QPC) for the superconducting magnets of the JT-60SA Satellite Tokamak, which will operate in Naka, Japan. After the completion of the system detailed design in summer 2011, the manufacture of the poloidal and toroidal prototypes was launched and completed at the beginning of 2012. Several factory type tests on the main components have been done at the manufacturers' premises and are described in this paper. Then, two main campaigns have been performed to test the operation of the overall poloidal and toroidal QPC prototypes; the main results are reported in the paper too.
松川 誠; 島田 勝弘; 山内 邦仁; Gaio, E.*; Ferro, A.*; Novello, L.*
Plasma Science and Technology, 15(3), p.257 - 260, 2013/03
被引用回数:7 パーセンタイル:29.97(Physics, Fluids & Plasmas)トカマク装置において高性能プラズマを実現するためには、誤差磁場補正が重要な課題の一つである。実際、国際熱核融合実験炉ITERにおいては、誤差磁場補正用の超伝導コイルが計画されており、JT-60SA装置では常伝導コイルが使用される予定である。同様のコイルは、他の世界中の多くの装置で据え付けられており、また運転中でもある。JT-60SA装置の場合、誤差磁場補正コイルは12個(あるいは18個)のセクターコイルが真空容器内に設置される予定である。本論文は、このような誤差磁場補正コイル用電源の回路構成と制御方式にかかわる概念設計について述べるものである。結論としては、電流フィーダや半導体電力素子の数を最小化することのできる多相インバータが、コスト面のみならず、軸対称成分による誘導電圧を相殺できる点などから、最も有望であることを示す。
島田 勝弘; 寺門 恒久; 山内 邦仁; 松川 誠; Baulaigue, O.*; Coletti, R.*; Coletti, A.*; Novello, L.*
Plasma Science and Technology, 15(2), p.184 - 187, 2013/02
被引用回数:5 パーセンタイル:21.70(Physics, Fluids & Plasmas)In JT-60SA, the four thyristor converters in poloidal field coil (PFC) power supplies are used for plasma initiation. In this case, the large reactive power fluctuation induced by the "Booster PS" is the cause of large voltage fluctuation across the terminals of the motor-generator. To minimize the reactive power fluctuation during plasma initiation, an asymmetric control method and a sequential timing control to start/stop each "Booster PS" are foreseen. To evaluate the effectiveness of above control methods for the "Booster PS", the reactive power has been simulated by using "PSCAD/EMTDC" code. From the simulation it results that the reactive power induced by the four units of the "Booster PS" can be dramatically reduced. In addition, the voltage fluctuation of the motor-generator connected to the "Booster PS" is expected to be suppressed to less than 10%, which ensures the stable control of JT-60SA magnet power supplies.
山内 邦仁; 島田 勝弘; 寺門 恒久; 松川 誠; Coletti, R.*; Lampasi, A.*; Gaio, E.*; Coletti, A.*; Novello, L.*
Plasma Science and Technology, 15(2), p.148 - 151, 2013/02
被引用回数:6 パーセンタイル:25.86(Physics, Fluids & Plasmas)One of the most essential issues for designing a power supply system of superconducting coil is to avoid any overvoltage. Here, the most concerned overvoltage can appear between turns due to the transiently concentrated voltage distribution inside the coil, which is mainly caused by parasitic capacitances and high dv/dt. For this reason, the coil power supply, especially fast high voltage generation circuit, should equip proper snubber(s) in order to suppress the dv/dt. However, it is too complicated to accurately evaluate the transient voltage in the coil because of the distributed parameters of the mutual inductance between turns and the capacitance between adjacent conductors. In this study, such a complicated system is modeled with reasonably detailed circuit network with lumped ones, and is integrated into the overall simulation model of JT-60SA PF coil circuit. Then a detailed circuit analysis is conducted in order to evaluate the possible voltage transient in the coil circuit. As a result, appropriate circuit parameters in the coil power supply including the snubbers are obtained.
村上 陽之; 木津 要; 土屋 勝彦; 吉田 清; 山内 邦仁; 島田 勝弘; 寺門 恒久; 松川 誠; 長谷川 満*; 湊 恒明*; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.9501405_1 - 9501405_5, 2012/06
被引用回数:4 パーセンタイル:29.08(Engineering, Electrical & Electronic)超伝導コイルの開発において、ターン間絶縁の耐電圧特性は重要な設計パラメータである。しかし実機コイルのターン間電圧は、電源の電圧変動やコイル内の共振現象により、理想的に電圧が分布した場合に比べ局所的にターン間電圧が高くなる危険性が指摘されている。そこで電源の電圧変動を評価するためJT-60SAと同等の大型電源であるJT-60Uの電源電圧測定を実施した。また、コイル内の共振現象を把握するため、EF4ダミーパンケーキを用いた共振特性試験及び数値解析によりEFコイルの共振特性を評価した。これらの結果、実際のターン間電圧は理想的な電圧分布から大きく外れないことが確認できた。
Gaio, E.*; Maistrello, A.*; Coffetti, A.*; Gargano, T.*; Perna, M.*; Novello, L.*; Coletti, A.*; 松川 誠; 山内 邦仁
IEEE Transactions on Plasma Science, 40(3), p.557 - 563, 2012/03
被引用回数:29 パーセンタイル:76.38(Physics, Fluids & Plasmas)This paper describes the detailed design of the quench protection circuits (QPC) for the superconducting toroidal field (TF) and poloidal field (PF) magnets of the Satellite Tokamak JT-60SA, which will be installed in Naka, Japan. The nominal currents to be interrupted and the maximum reapplied voltages are 25.7 kA and 2.8 kV for the TF QPCs and 20 kA and 5 kV for PF QPCs. The innovative solution proposed in the QPC design is based on a hybrid circuit breaker (CB) composed of a mechanical Bypass Switch for conducting the continuous current, in parallel to a static CB for current interruption. The main choices of the final design are presented and discussed, either to confirm or to update and complete the study performed at the conceptual design level.
Coletti, A.*; Baulaigue, O.*; Cara, P.*; Coletti, R.*; Ferro, A.*; Gaio, E.*; 松川 誠; Novello, L.*; Santinelli, M.*; 島田 勝弘; et al.
Fusion Engineering and Design, 86(6-8), p.1373 - 1376, 2011/10
被引用回数:21 パーセンタイル:82.40(Nuclear Science & Technology)JT-60SA is a joint international research and development project involving Japan and Europe, in the frame of the "Broader Approach Agreement", for the construction and operation of a new tokamak intended to prepare and support ITER operation. JT-60SA is to be built in Naka, Japan, using existing infrastructures and subsystems of the former JT-60U experiment, as much as possible. SA, as "super advanced", refers to the use of Superconducting Coils Magnets (SCM) and to the study of advanced modes in plasma operation. The SCM system includes Toroidal and Poloidal Field Coils (TFC and PFC respectively). In addition the machine features a number of normal conducting coils: Fast Plasma Control Coils (FPCC), a Resistive Wall Mode Control Coils and the Error Field Correction Coils. The paper describes the main features of the JT-60SA SCM Power Supply System (SCMPS) with special regard to coil current regulation mode and SCM protection.
島田 勝弘; Baulaigue, O.*; Cara, P.*; Coletti, A.*; Coletti, R.*; 松川 誠; 寺門 恒久; 山内 邦仁
Fusion Engineering and Design, 86(6-8), p.1427 - 1431, 2011/10
被引用回数:7 パーセンタイル:48.56(Nuclear Science & Technology)In the initial research phase of JT-60SA, the plasma heating operation of 30MW-60s or 20MW-100s is planned for 5.5 MA single null divertor plasmas. To achieve this operation, AC power source of the medium voltage of 18 kV and 7 GJ has to be provided in total to the poloidal field coil power supplies and additional heating devices such as Neutral Beam Injection (NBI) and Electron Cyclotron Radio Frequency (ECRF). In this paper, the proposed AC power supply system in JT-60SA was estimated from the view point of available power, and harmonic currents based on the standard plasma operation scenario during the initial research phase. This AC power supply system consists of the reused JT-60 power supply facilities including motor generators with flywheel, AC breakers, and harmonic filters, etc. to make it cost effective. In addition, the conceptual design of the upgraded AC power supply system for the ultimate heating power of 41MW-100s in the extended research phase is also described.
春日井 敦; 山内 邦仁
電気学会研究会資料,原子力研究会(NE-11-001004・006010), p.1 - 3, 2011/09
核融合エネルギーシステム実現のための先進的大電力技術調査専門委員会において調査・検討されたこれらの先進的大電力技術の一部を紹介し、核融合エネルギー技術の広がりと学術分野や産業分野への貢献を明らかにするとともに、今後期待される新技術創出への課題と展望を明らかにする。
山内 邦仁; 島田 勝弘; 寺門 恒久; 松川 誠; Cara, P.*; Gaio, E.*; Santinelli, M.*; Coletti, R.*; Coletti, A.*
Journal of Plasma and Fusion Research SERIES, Vol.9, p.220 - 225, 2010/08
High current of about 500 kA will be induced in the passive structures such as vacuum vessel and stabilizing plate at plasma initiation in JT-60SA, because the total resistance of the passive structure is approximately 16 and the breakdown electric field of 0.5 V/m is expected for stable plasma initiation from the experiments of JT-60U. Therefore, a precise evaluation of the magnetic field performance using the accurate circuit analysis model has to be conducted to obtain stable plasma breakdown and for designing the detail of power supply system. In this paper, the preparation procedure of the analysis model will be presented. Then, some circuit analysis results of plasma breakdown will be given using ideal power supply and actual thyristor converter model for comparison. The delay effect of converter voltage control and the discrepancy of current control would be summarized as the first achievement. The voltage fluctuation of generator (H-MG, 400 MVA) at plasma initiation will be also described, because large reactive power fluctuation may cause large voltage fluctuation and sudden phase shift of the AC source voltage of thyristor converter.
松川 誠; 寺門 恒久; 山内 邦仁; 島田 勝弘; Cara, P.*; Gaio, E.*; Novello, L.*; Ferro, A.*; Coletti, R.*; Santinelli, M.*; et al.
Journal of Plasma and Fusion Research SERIES, Vol.9, p.264 - 269, 2010/08
Reliable plasma initiation is very important in the nuclear fusion devices especially in superconducting tokamaks. Applicable breakdown electric field would be limited up to level of 0.5 V/m to suppress large AC losses in the superconducting magnet. Furthermore, induced current in the passive structure such as vacuum vessel and stabilizing plate would increased easily to the comparable level of plasma current with several hundred kA even in the case of ECH assist breakdown. Therefore, optimization of the applied voltage to the poloidal field coil is necessary for stable plasma initiation. In this paper, the rationalized plasma initiation scenario using cost effectively designed power supply system will be provided.
松川 誠; 島田 勝弘; 寺門 恒久; 山内 邦仁; 大森 栄和; 岡野 潤
no journal, ,
JT-60SA装置の交流電源システムに関する発表である。JT-60SAの負荷は、大幅な無効電力変動を伴うポロイダル磁場コイル電源と、力率の変動は比較的少ないが消費エネルギーの大きいプラズマ加熱・電流駆動装置に大別できる。前者を直接電力系統に接続するには、大容量のアクティブフィルタなどを準備する必要があり、極めて高コストとなる。そこで、JT-60SAの運転シナリオを検討し、現有のH-MG(400MVA-2.6GJ)をおもにポロイダル磁場コイル電源に使用することにした。しかし、JT-60SAのプラズマ加熱・電流駆動入力は、初期実験段階ではせいぜい20MW-100sもしくは30MW-60sであるが、最終的には41MW-100sの実験運転が計画されている。これを実現するには、現有の連続励磁が可能な2台の電動発電機のエネルギーでは不足するため、新たなエネルギー蓄積要素を設けるか、電力系統からの受電を増大する必要がある。さらに、P-NBI, N-NBI及びECRF装置で、それぞれエネルギー変換効率も力率も異なるので、電力系統への影響に関しては障害電力の流出に細心の注意が必要となる。講演では概念設計の現状を報告するとともに、技術的な制約条件や実現への課題について述べる。
山内 邦仁; 島田 勝弘; 岡野 潤; 大森 栄和; 寺門 恒久; 栗原 研一
no journal, ,
ITERのサテライトトカマクとして計画されているJT-60SAのポロイダル磁場コイルでは、プラズマの着火と立ち上げの際に高電圧を必要とする一方で、運転の大部分を占める定常時にはほとんど電圧を必要としない。したがって、長時間ないし連続定格の低電圧電源と短時間定格の高電圧電源の組合せが価格と大きさの面で合理的である。ただし、このためにはコイルの通電中に最大20kAの直流大電流を適切かつ滑らかに転流し、短時間定格の高電圧電源をバイパスする機構が不可欠である。そこで、実用性と経済性の観点からこれらの要求を満たすバイパススイッチを新たに提案し、回路シミュレーションにより妥当性を評価した。本講演では、これらの設計検討の結果について報告する。
島田 勝弘; 寺門 恒久; 大森 栄和; 岡野 潤; 山内 邦仁; 栗原 研一
no journal, ,
ITERのブローダーアプローチの一つであるJT-60SA計画では、トロイダル磁場コイル及びポロイダル磁場コイルが超電導化される。コイルの超電導化により、定常時では低電圧制御が可能となるが、プラズマ着火及び立ち上げ時には高電圧を必要とする。このような特殊な運転を実現するために、既存のJT-60U電源を有効に再利用した新しいコイル電源の回路設計検討を行い、併せてそれらの制御手法について検討も行った。検討の結果、トロイダル磁場コイル電源は、急速な励磁・消磁の必要がないので低電圧大電流電源とした。ポロイダル磁場コイル電源は、定常的に制御を行う低電圧のベース電源とプラズマ着火及び立ち上げ用の高電圧電源により構成し、高電圧電源として、既存JT-60ポロイダル磁場コイル電源を再利用したブースター/アシスト電源あるいは抵抗に電流を転流させて高電圧を発生させる高電圧発生回路を採用した。本講演では、超電導コイル電源の回路構成及びその制御手法について発表する。
松川 誠; 島田 勝弘; 鈴木 隆博; 寺門 恒久; 山内 邦仁
no journal, ,
JT-60SA装置では、真空容器外に設置するポロイダル磁場コイル(PFC)が超伝導のため、制御のために印加できる周回電圧は現JT-60Uの10分の1程度である。さらに、真空容器や安定化板などの一周抵抗も約10分の1となるため、プラズマ断面の高速位置制御用に、真空容器内に常伝導コイル(FPCC)を設置する予定である。本発表は、JT-60SA装置の磁場シールド効果を考慮した場合の、プラズマ高速位置制御コイル電源に要求される応答特性を明らかにするものである。
山内 邦仁; Baulaigue, O.*; Coletti, A.*; Coletti, R.*; Ferro, A.*; Gaio, E.*; Lampasi, A.*; 松川 誠; Novello, L.*; 島田 勝弘; et al.
no journal, ,
The JT-60SA tokamak device consists of superconducting toroidal field (TF) and poloidal field (PF) coils, and some in-vessel coils. All of 18 TF coils are connected in series and powered by a low-voltage unidirectional DC power supply (PS), while three Quench Protection Circuits (QPCs) are inserted for every six TF coils. Meanwhile, each PF coil circuit is independent from the others, and a bidirectional DC current is driven for plasma current ramp-up and sustainment by series-connected Base PS, and Switching Network Unit or Booster PS. TF coils are energized by commercial electric power grid directly, but the rest of the coils are planned to be powered by the existing motor-generator of JT-60. This paper describes the key features and the expected performances of the main PS system for the superconducting magnets in JT-60SA.