Pub Date : 2024-10-26DOI: 10.1016/j.fusengdes.2024.114701
Y.L. Yu , Z.Y. Chen , W. Yan , S.G. Xia , N.C. Wang , Z.S. Nie , X. Zhou , Y. Sheng , Y.W. Sun , J.G. Fang , Y. Zhong , the J-TEXT Team
Plasma disruptions can cause significant damage to tokamak. Currently, the primary method for mitigating disruptions is the injection of a substantial amount of impurities. The electromagnetic injection method offers a high injection speed and rapid response time, making it a promising technique for impurity injection. The first Electromagnetic Pellet Injection System (EMPI), developed by the J-TEXT team, is capable of launching pellets at high velocities and features a specialized deceleration rail that ensures safe separation of the armature and pellet. However, this system lacks an armature recovery device and a vacuum system. In this work, a second generation EMPI has been developed, which has a vacuum system and a curved recovery rail. The curved recovery rail facilitates the smooth retrieval of the armature, enhancing the safety of the recycling process. Additionally, this new system employs an augmented rail design that improves launch performance. Test results indicate that the maximum current of the new EMPI has been reduced by approximately 60%, while the maximum launch speed has increased by around 20%.
{"title":"Optimal design and experimental testing of EMPI system for plasma disruption mitigation on J-TEXT","authors":"Y.L. Yu , Z.Y. Chen , W. Yan , S.G. Xia , N.C. Wang , Z.S. Nie , X. Zhou , Y. Sheng , Y.W. Sun , J.G. Fang , Y. Zhong , the J-TEXT Team","doi":"10.1016/j.fusengdes.2024.114701","DOIUrl":"10.1016/j.fusengdes.2024.114701","url":null,"abstract":"<div><div>Plasma disruptions can cause significant damage to tokamak. Currently, the primary method for mitigating disruptions is the injection of a substantial amount of impurities. The electromagnetic injection method offers a high injection speed and rapid response time, making it a promising technique for impurity injection. The first Electromagnetic Pellet Injection System (EMPI), developed by the J-TEXT team, is capable of launching pellets at high velocities and features a specialized deceleration rail that ensures safe separation of the armature and pellet. However, this system lacks an armature recovery device and a vacuum system. In this work, a second generation EMPI has been developed, which has a vacuum system and a curved recovery rail. The curved recovery rail facilitates the smooth retrieval of the armature, enhancing the safety of the recycling process. Additionally, this new system employs an augmented rail design that improves launch performance. Test results indicate that the maximum current of the new EMPI has been reduced by approximately 60%, while the maximum launch speed has increased by around 20%.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.fusengdes.2024.114689
Yuan Xiang, Liqun Shi, Bin Zhang
Tungsten (W), the wall material in Tokamak fusion reactors, is subjected to irradiation from high-energy neutrons and high-flux deuterium (D) plasma. In particular, in the presence of deuterium bubbles, neutron irradiation can significantly exacerbate the deterioration of the mechanical properties of the material. However, few studies have focused on the effect of neutron irradiation on deuterium bubbles in tungsten, and the mechanism of deuterium bubble evolution under neutron irradiation remains unclear. In this study, we simulate the evolution of D bubbles using a molecular dynamics approach, revealing a complete evolutionary process: standing, expanding, and bursting. In addition, the results of primary knock-on atom (PKA) irradiation of D bubbles show that high-energy neutrons transfer energy to the D atoms inside the bubbles through collision cascades, leading to a surge in the total pressure inside the bubbles, which contributes to the evolution of the D bubbles. Temperature, D atom to vacancy ratio (D/V), and PKA energy determine the behavior of D bubbles in tungsten. The effects of these three variables on the evolution of D bubbles are summarized in detail by counting the states of the D bubbles and comparing the changes in pressure and volume inside the D bubbles under specific conditions. We observed a modification process by neutron irradiation on a pure W surface with collision cascades generating Frenkel defect pairs within the W lattice. By analyzing the concentration changes, the evolution of Frenkel defects is divided into three stages: growth, elimination, and stabilization. The present work proposes a possible mechanism to explain the evolution of D bubbles stimulated by PKA cascades induced by neutron irradiation, providing an important theoretical guideline for the improvement and selection of optimal materials oriented towards the plasma wall.
钨（W）是托卡马克核聚变反应堆的壁材料，会受到高能中子和高通量氘（D）等离子体的辐照。特别是在存在氘气泡的情况下，中子辐照会显著加剧材料机械性能的恶化。然而，很少有研究关注中子辐照对钨中氘气泡的影响，而且中子辐照下氘气泡演化的机理仍不清楚。在本研究中，我们利用分子动力学方法模拟了氘泡的演化过程，揭示了一个完整的演化过程：驻留、膨胀和破裂。此外，D气泡的原初敲击原子（PKA）辐照结果表明，高能中子通过碰撞级联将能量传递给气泡内的D原子，导致气泡内总压力骤增，从而促进了D气泡的演化。温度、D 原子与空位比（D/V）和 PKA 能量决定了钨中 D 气泡的行为。我们通过计算 D 气泡的状态，比较特定条件下 D 气泡内部压力和体积的变化，详细总结了这三个变量对 D 气泡演化的影响。我们观察到纯 W 表面在中子辐照下的改性过程，碰撞级联在 W 晶格内产生了 Frenkel 缺陷对。通过分析浓度变化，我们将弗伦克尔缺陷的演化过程分为三个阶段：生长、消除和稳定。本研究提出了一种可能的机制来解释中子辐照诱导的 PKA 级联刺激 D 气泡的演化，为改进和选择面向等离子体壁的最佳材料提供了重要的理论指导。
{"title":"Molecular dynamics simulations of deuterium bubble evolution in tungsten under neutron irradiation and non-irradiation conditions","authors":"Yuan Xiang, Liqun Shi, Bin Zhang","doi":"10.1016/j.fusengdes.2024.114689","DOIUrl":"10.1016/j.fusengdes.2024.114689","url":null,"abstract":"<div><div>Tungsten (W), the wall material in Tokamak fusion reactors, is subjected to irradiation from high-energy neutrons and high-flux deuterium (D) plasma. In particular, in the presence of deuterium bubbles, neutron irradiation can significantly exacerbate the deterioration of the mechanical properties of the material. However, few studies have focused on the effect of neutron irradiation on deuterium bubbles in tungsten, and the mechanism of deuterium bubble evolution under neutron irradiation remains unclear. In this study, we simulate the evolution of D bubbles using a molecular dynamics approach, revealing a complete evolutionary process: standing, expanding, and bursting. In addition, the results of primary knock-on atom (PKA) irradiation of D bubbles show that high-energy neutrons transfer energy to the D atoms inside the bubbles through collision cascades, leading to a surge in the total pressure inside the bubbles, which contributes to the evolution of the D bubbles. Temperature, D atom to vacancy ratio (D/V), and PKA energy determine the behavior of D bubbles in tungsten. The effects of these three variables on the evolution of D bubbles are summarized in detail by counting the states of the D bubbles and comparing the changes in pressure and volume inside the D bubbles under specific conditions. We observed a modification process by neutron irradiation on a pure W surface with collision cascades generating Frenkel defect pairs within the W lattice. By analyzing the concentration changes, the evolution of Frenkel defects is divided into three stages: growth, elimination, and stabilization. The present work proposes a possible mechanism to explain the evolution of D bubbles stimulated by PKA cascades induced by neutron irradiation, providing an important theoretical guideline for the improvement and selection of optimal materials oriented towards the plasma wall.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.fusengdes.2024.114697
Jeongwon Lee, Jayhyun Kim, Hyunsun Han, Youngho Lee, Sang-hee Hahn, Jun-Gyo Bak, Mi Joung, Hyungho Lee, Yong-Un Nam
Plasma startup experiments after the KSTAR upgrade of a lower divertor from carbon to tungsten have been studied during the KSTAR 2023 plasma campaign. In-vessel eddy currents, especially those induced on the divertor supporting structure in the toroidal direction, are significantly altered by the upgrade of the lower divertor configuration. These changes could affect the poloidal field configuration of the plasma startup phase, which is essential for the reliable breakdown and burn-through of deuterium neutral gas and the stable rise of the plasma current. Here, we present the development process of a new startup scenario that considers these upgrades. The vacuum magnetic field design code was utilized to estimate the changes in the poloidal field due to the new divertor configuration. Modifications to the startup scenario were prepared to compensate for the different effects of eddy currents, and experimental validation and optimization were performed during the initial phase of the KSTAR 2023 campaign. The final version of the startup scenario and plasma startup data are presented, and the reliability of the new startup scenario was also confirmed throughout the remainder of the KSTAR campaign.
{"title":"Startup experiment with the newly installed lower tungsten divertor of KSTAR","authors":"Jeongwon Lee, Jayhyun Kim, Hyunsun Han, Youngho Lee, Sang-hee Hahn, Jun-Gyo Bak, Mi Joung, Hyungho Lee, Yong-Un Nam","doi":"10.1016/j.fusengdes.2024.114697","DOIUrl":"10.1016/j.fusengdes.2024.114697","url":null,"abstract":"<div><div>Plasma startup experiments after the KSTAR upgrade of a lower divertor from carbon to tungsten have been studied during the KSTAR 2023 plasma campaign. In-vessel eddy currents, especially those induced on the divertor supporting structure in the toroidal direction, are significantly altered by the upgrade of the lower divertor configuration. These changes could affect the poloidal field configuration of the plasma startup phase, which is essential for the reliable breakdown and burn-through of deuterium neutral gas and the stable rise of the plasma current. Here, we present the development process of a new startup scenario that considers these upgrades. The vacuum magnetic field design code was utilized to estimate the changes in the poloidal field due to the new divertor configuration. Modifications to the startup scenario were prepared to compensate for the different effects of eddy currents, and experimental validation and optimization were performed during the initial phase of the KSTAR 2023 campaign. The final version of the startup scenario and plasma startup data are presented, and the reliability of the new startup scenario was also confirmed throughout the remainder of the KSTAR campaign.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.fusengdes.2024.114692
Zhanze Shi, Zhuohui Chen, Bintao Yu, Hu Lin, Bing Bai, Xinfu He
China Low-activation Ferrite steel (CLF-1), as one of the structural materials developed in China for fusion reactors, is a Reduced activation Ferritic/Martensitic (RAFM) steel modeled after the traditional T91 steel (9Cr-1Mo-0.2V-0.08Nb). For fusion reactor materials, the Charpy impact testing is an important method to assess their notch sensitivity. In this study, Charpy impact tests were conducted on CLF-1 steel using Charpy V-notch specimens (CVN) and Miniature Charpy V-notch specimens (Kleinstprobe, KLST) to assess the impact behavior of CLF-1 steel, and data normalization was performed on the KLST specimen. The results show that as the specimen size of CLF-1 steel decreased, the curves of impact absorbed energy, lateral expansion, and shear fracture appearance shifted towards lower temperatures, and the impact absorbed energy significantly decreased. Both the macroscopic and microscopic characteristics of the specimens obtained from the experiments indicated that KLST specimens could achieve the same fracture characteristics as CVN specimens. Additionally, at the same experimental temperature, KLST specimens exhibited a higher proportion of ductile fracture regions.
中国低活化铁素体钢（CLF-1）是中国为聚变反应堆开发的结构材料之一，是一种以传统 T91 钢（9Cr-1Mo-0.2V-0.08Nb）为模型的低活化铁素体/马氏体（RAFM）钢。对于聚变反应堆材料而言，夏比冲击试验是评估其缺口敏感性的重要方法。本研究使用夏比 V 型缺口试样（CVN）和微型夏比 V 型缺口试样（Kleinstprobe，KLST）对 CLF-1 钢进行了夏比冲击试验，以评估 CLF-1 钢的冲击行为，并对 KLST 试样进行了数据归一化处理。结果表明，随着 CLF-1 钢试样尺寸的减小，冲击吸收能量、横向膨胀和剪切断裂外观曲线向低温方向移动，冲击吸收能量显著降低。实验所得试样的宏观和微观特征均表明，KLST 试样可获得与 CVN 试样相同的断裂特征。此外，在相同的实验温度下，KLST 试样表现出更高比例的韧性断裂区域。
{"title":"Assessment of the impact behavior of CLF-1 steel with Charpy V-notch testing and miniature Charpy V-notch testing","authors":"Zhanze Shi, Zhuohui Chen, Bintao Yu, Hu Lin, Bing Bai, Xinfu He","doi":"10.1016/j.fusengdes.2024.114692","DOIUrl":"10.1016/j.fusengdes.2024.114692","url":null,"abstract":"<div><div>China Low-activation Ferrite steel (CLF-1), as one of the structural materials developed in China for fusion reactors, is a Reduced activation Ferritic/Martensitic (RAFM) steel modeled after the traditional T91 steel (9Cr-1Mo-0.2V-0.08Nb). For fusion reactor materials, the Charpy impact testing is an important method to assess their notch sensitivity. In this study, Charpy impact tests were conducted on CLF-1 steel using Charpy V-notch specimens (CVN) and Miniature Charpy V-notch specimens (Kleinstprobe, KLST) to assess the impact behavior of CLF-1 steel, and data normalization was performed on the KLST specimen. The results show that as the specimen size of CLF-1 steel decreased, the curves of impact absorbed energy, lateral expansion, and shear fracture appearance shifted towards lower temperatures, and the impact absorbed energy significantly decreased. Both the macroscopic and microscopic characteristics of the specimens obtained from the experiments indicated that KLST specimens could achieve the same fracture characteristics as CVN specimens. Additionally, at the same experimental temperature, KLST specimens exhibited a higher proportion of ductile fracture regions.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.fusengdes.2024.114694
L. Piron , Carlos Paz-Soldan , Morten Lennholm , Krassimir Kirov , Daniel Valcarcel , Matteo Baruzzo , Tommaso Bolzonella , Rachele Cicioni , Peter De Vries , Nicolò Ferron , Matteo Gambrioli , Y. Gribov , R. Henriques , Emmanuel Joffrin , Piero Martin , Massimiliano Mattei , Gabriele Manduchi , Luigi Pangione , Leonardo Pigatto , Alfredo Pironti , Luca Zabeo
This work reports on error field identification and control studies carried out at JET and insights on the development of the empirical EF controller for ITER. The empirical EF controller has been included in the JET real-time central controller following the execution of the non-disruptive compass scan method (Paz-Soldan C. et al., Nuclear Fusion 62 (2022) 126007), which allowed the identification of the EF source and the currents for error field compensation. When testing the empirical EF controller, born locked n = 1 modes have been observed to spin-up and a lower density regime has been explored in the 1.8 MA plasma current, 2.1 T toroidal magnetic field scenario than otherwise achievable. These experimental results demonstrate the benefits of EF correction. In preparation of EF correction studies in ITER, the empirical EF controller for ITER has been developed and integrated in the plasma control system database.
这项工作报告了在 JET 开展的误差场识别和控制研究，以及开发用于热核实验堆的经验 EF 控制器的进展情况。在执行非中断罗盘扫描方法（Paz-Soldan C. 等人，Nuclear Fusion 62 (2022) 126007）之后，JET 实时中央控制器中包含了经验性外频控制器，该方法允许识别外频源和用于误差场补偿的电流。在测试经验 EF 控制器时，观察到天生锁定的 n = 1 模式自旋上升，并在 1.8 MA 等离子体电流、2.1 T 环形磁场情况下探索了比其他方法更低的密度机制。这些实验结果证明了 EF 校正的好处。为准备在热核实验堆中进行 EF 校正研究，开发了用于热核实验堆的经验 EF 控制器，并将其集成到等离子体控制系统数据库中。
{"title":"Empirical error field control at JET in preparation of ITER start-up","authors":"L. Piron , Carlos Paz-Soldan , Morten Lennholm , Krassimir Kirov , Daniel Valcarcel , Matteo Baruzzo , Tommaso Bolzonella , Rachele Cicioni , Peter De Vries , Nicolò Ferron , Matteo Gambrioli , Y. Gribov , R. Henriques , Emmanuel Joffrin , Piero Martin , Massimiliano Mattei , Gabriele Manduchi , Luigi Pangione , Leonardo Pigatto , Alfredo Pironti , Luca Zabeo","doi":"10.1016/j.fusengdes.2024.114694","DOIUrl":"10.1016/j.fusengdes.2024.114694","url":null,"abstract":"<div><div>This work reports on error field identification and control studies carried out at JET and insights on the development of the empirical EF controller for ITER. The empirical EF controller has been included in the JET real-time central controller following the execution of the non-disruptive compass scan method (Paz-Soldan C. et al., Nuclear Fusion 62 (2022) 126007), which allowed the identification of the EF source and the currents for error field compensation. When testing the empirical EF controller, born locked <em>n</em> = 1 modes have been observed to spin-up and a lower density regime has been explored in the 1.8 MA plasma current, 2.1 T toroidal magnetic field scenario than otherwise achievable. These experimental results demonstrate the benefits of EF correction. In preparation of EF correction studies in ITER, the empirical EF controller for ITER has been developed and integrated in the plasma control system database.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.fusengdes.2024.114690
Van-Dung Truong, William Brace
The engineering design of components and systems in a fusion power plant, an example of a complex system with extreme conditions, requires careful consideration and balance of the numerous associated risks. Key risks are observed from several perspectives and categorised as failure modes, situational and quality risks. Several methods exist for the separate consideration of these risks at the various design phases. However, an optimum approach is to consider all risks and balance the effects during the early design phase. The paper introduces a novel methodology to consider all associated risks at the conceptual design phase by combining a generalised Π-theorem and dimensional analysis for qualitative physics reasoning. The method is applied to a Balance of Plant components as a case study. Initial results show positive concurrent consideration and analysis of all risks in the conceptual stage.
{"title":"Balanced-risk analysis in the engineering design of complex systems with extreme conditions","authors":"Van-Dung Truong, William Brace","doi":"10.1016/j.fusengdes.2024.114690","DOIUrl":"10.1016/j.fusengdes.2024.114690","url":null,"abstract":"<div><div>The engineering design of components and systems in a fusion power plant, an example of a complex system with extreme conditions, requires careful consideration and balance of the numerous associated risks. Key risks are observed from several perspectives and categorised as failure modes, situational and quality risks. Several methods exist for the separate consideration of these risks at the various design phases. However, an optimum approach is to consider all risks and balance the effects during the early design phase. The paper introduces a novel methodology to consider all associated risks at the conceptual design phase by combining a generalised Π-theorem and dimensional analysis for qualitative physics reasoning. The method is applied to a Balance of Plant components as a case study. Initial results show positive concurrent consideration and analysis of all risks in the conceptual stage.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.fusengdes.2024.114691
Ziqiang Wang , Chen Yang , Ning Gao , Xuebang Wu , Zhongwen Yao
The investigation into irradiation hardening and embrittlement is of critical importance in nuclear material subject. This work explores the applications of machine learning (ML) to predict the yield strength of irradiated type 316 stainless steels. A dataset comprising 354 samples is compiled through an extensive review of prior experimental studies. Each sample has 23 potentially influential features. Five distinct machine learning models are trained and evaluated. Among these models, the Gradient Boosting (GB) model demonstrates superior prediction performance and robust stability. The prominent factors identified by the GB model are in reasonable agreement with established knowledge regarding the determinants of yield strength in irradiated type 316 stainless steels. These findings provide critical insights into the mechanical properties of irradiated type 316 stainless steels.
{"title":"Machine learning - assisted prediction of yield strength in irradiated type 316 stainless steels","authors":"Ziqiang Wang , Chen Yang , Ning Gao , Xuebang Wu , Zhongwen Yao","doi":"10.1016/j.fusengdes.2024.114691","DOIUrl":"10.1016/j.fusengdes.2024.114691","url":null,"abstract":"<div><div>The investigation into irradiation hardening and embrittlement is of critical importance in nuclear material subject. This work explores the applications of machine learning (ML) to predict the yield strength of irradiated type 316 stainless steels. A dataset comprising 354 samples is compiled through an extensive review of prior experimental studies. Each sample has 23 potentially influential features. Five distinct machine learning models are trained and evaluated. Among these models, the Gradient Boosting (GB) model demonstrates superior prediction performance and robust stability. The prominent factors identified by the GB model are in reasonable agreement with established knowledge regarding the determinants of yield strength in irradiated type 316 stainless steels. These findings provide critical insights into the mechanical properties of irradiated type 316 stainless steels.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-18DOI: 10.1016/j.fusengdes.2024.114693
Joohwan Hong , Changrae Seon , Min-Gu Won , Yoo Kwan Kim , Boseong Kim , Byungsu Ma , Jaemin Kim , HeeJin Shim , MunSeong Cheon
The divertor vacuum ultraviolet (VUV) spectrometer is a diagnostic system in the ITER tokamak, monitoring impurity content and behavior in the divertor region. The first mirror of the spectrometer, made of silicon carbide (SiC), is exposed to harsh environmental conditions, including high temperatures and significant inertial loads from electromagnetic disruption events. To ensure its reliable performance, we have designed and tested a robust mirror holder assembly. This paper introduces a novel design of the first mirror holder assembly for the ITER divertor VUV spectrometer and presents the results from comprehensive vibration tests conducted on a full-scale mock-up. The design features a double-holder structure with spring plate assemblies to accommodate thermal expansion and resist vibrational loads. The mock-up underwent a series of resonance search, sine dwell, and random vibration tests, replicating the expected loads during vertical displacement events in ITER. The mirror holder assembly and the dummy mirror successfully withstood the vibration tests without damage, validating the design for the ITER environment. The results demonstrate the robustness and reliability of the mirror holder assembly, ensuring the accurate and reliable operation of the divertor VUV spectrometer in ITER.
{"title":"Design and vibration test of first mirror mount assembly for ITER divertor VUV spectrometer","authors":"Joohwan Hong , Changrae Seon , Min-Gu Won , Yoo Kwan Kim , Boseong Kim , Byungsu Ma , Jaemin Kim , HeeJin Shim , MunSeong Cheon","doi":"10.1016/j.fusengdes.2024.114693","DOIUrl":"10.1016/j.fusengdes.2024.114693","url":null,"abstract":"<div><div>The divertor vacuum ultraviolet (VUV) spectrometer is a diagnostic system in the ITER tokamak, monitoring impurity content and behavior in the divertor region. The first mirror of the spectrometer, made of silicon carbide (SiC), is exposed to harsh environmental conditions, including high temperatures and significant inertial loads from electromagnetic disruption events. To ensure its reliable performance, we have designed and tested a robust mirror holder assembly. This paper introduces a novel design of the first mirror holder assembly for the ITER divertor VUV spectrometer and presents the results from comprehensive vibration tests conducted on a full-scale mock-up. The design features a double-holder structure with spring plate assemblies to accommodate thermal expansion and resist vibrational loads. The mock-up underwent a series of resonance search, sine dwell, and random vibration tests, replicating the expected loads during vertical displacement events in ITER. The mirror holder assembly and the dummy mirror successfully withstood the vibration tests without damage, validating the design for the ITER environment. The results demonstrate the robustness and reliability of the mirror holder assembly, ensuring the accurate and reliable operation of the divertor VUV spectrometer in ITER.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Inductively coupled plasma or ICP sources form a basis for multiple applications ranging from semiconductor fabrication to reliable heating systems for tokamak machines. To meet the functional requirements, ICP sources need efficient plasma formation utilizing the various input parameters. Operation of ICP sources is a complex and challenging task since it involves scanning a wide multi-dimensional parameter space involving filament bias, radio frequency (RF) power, gas pressure, matching parameters, and other system configurations. The foremost challenge is to maximize the coupling of RF power in the ion source for efficient plasma formation. Standard ICP sources use a matching network that consists of variable capacitors to compensate for plasma inductance to enable maximum power coupling. Identification of an accurate set of matching parameters for high power sources is a complex task and is generally driven by operator experience which is established after years of operations. Due to these challenges, recent developments in the area of machine learning can be utilized for identifying the underlying model function to make accurate predictions and explore an alternative approach to the existing Physics-electrical models developed for the estimation of matching parameters for plasma sources. The present work attempts to perform a data-driven model discovery for the identification of appropriate matching parameters utilizing machine learning algorithms. In this work, ROBIN, a high-power ICP source that operates with a 1MHz, 100 kW RF generator is considered which has been operational since 2011 and has generated a considerable database. This database can be utilized for training/developing data-driven models for the estimation of matching parameters for ensuring better power coupling. The paper describes the development of two data-driven regression models for predicting the coupling efficiency in terms of power factor (denoted by Cos) and the capacitor values based on input parameters utilizing well known algorithms such as support vector machine, random forest and neural networks. Emphasis has been laid on developing the models using parameters that are tuneable externally. Also, the effect of system configurations on parameter prediction is investigated. The developed machine learning-based models have achieved test accuracy scores of 0.93 and 0.91 for predicting Cos and capacitor values respectively. The paper presents the training and optimization process for various machine and deep learning algorithms in detail.
{"title":"Matching parameter estimation for high power Inductively coupled plasma sources using Machine learning techniques","authors":"Himanshu Tyagi , M.V. Joshi , Mainak Bandyopadhyay , M.J. Singh , Kaushal Pandya , Arun Chakraborty","doi":"10.1016/j.fusengdes.2024.114675","DOIUrl":"10.1016/j.fusengdes.2024.114675","url":null,"abstract":"<div><div>Inductively coupled plasma or ICP sources form a basis for multiple applications ranging from semiconductor fabrication to reliable heating systems for tokamak machines. To meet the functional requirements, ICP sources need efficient plasma formation utilizing the various input parameters. Operation of ICP sources is a complex and challenging task since it involves scanning a wide multi-dimensional parameter space involving filament bias, radio frequency (RF) power, gas pressure, matching parameters, and other system configurations. The foremost challenge is to maximize the coupling of RF power in the ion source for efficient plasma formation. Standard ICP sources use a matching network that consists of variable capacitors to compensate for plasma inductance to enable maximum power coupling. Identification of an accurate set of matching parameters for high power sources is a complex task and is generally driven by operator experience which is established after years of operations. Due to these challenges, recent developments in the area of machine learning can be utilized for identifying the underlying model function to make accurate predictions and explore an alternative approach to the existing Physics-electrical models developed for the estimation of matching parameters for plasma sources. The present work attempts to perform a data-driven model discovery for the identification of appropriate matching parameters utilizing machine learning algorithms. In this work, ROBIN, a high-power ICP source that operates with a 1MHz, 100 kW RF generator is considered which has been operational since 2011 and has generated a considerable database. This database can be utilized for training/developing data-driven models for the estimation of matching parameters for ensuring better power coupling. The paper describes the development of two data-driven regression models for predicting the coupling efficiency in terms of power factor (denoted by Cos<span><math><mi>ϕ</mi></math></span>) and the capacitor values based on input parameters utilizing well known algorithms such as support vector machine, random forest and neural networks. Emphasis has been laid on developing the models using parameters that are tuneable externally. Also, the effect of system configurations on parameter prediction is investigated. The developed machine learning-based models have achieved test accuracy scores of 0.93 and 0.91 for predicting Cos<span><math><mi>ϕ</mi></math></span> and capacitor values respectively. The paper presents the training and optimization process for various machine and deep learning algorithms in detail.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142537940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-15DOI: 10.1016/j.fusengdes.2024.114685
Pan Huang, Jiming Chen, Yiming Wang, Yanyu Chen, Zhengxing Wei, Shiyu Cui, Yi Zhou, Qian Li, Pinghuai Wang
HIP experiments were conducted at temperatures of 950, 900, and 850 °C for durations of 60, 135, and 240 min respectively in this study, the effect of bonding temperature and duration on the interfacial microstructure and mechanical properties of the joint was investigated. The results demonstrate that reducing the HIP temperature from 980 to 850 °C leads to a significant decrease in the thickness of the W/Fe reaction layer. This reduction enables bonding interfaces without reaction layer at temperatures of 900 and 850 °C. However, as the temperature decreases, there is an initial increase followed by a subsequent decrease in shear strength with a maximum shear strength achieved at 950 °C reaching up to 322 MPa. Prolonging the bonding duration at a temperature of 950 °C results in a rapid transition of W/Fe reaction layer from Fe2W to Fe3W3C which weakens the overall bonding performance. Conversely, increasing the bonding duration at temperatures of 900 and 850 °C has minimal impact on both interfacial microstructure and bonding strength.
在本研究中，分别在 950、900 和 850 ℃ 的温度和 60、135 和 240 分钟的持续时间内进行了 HIP 实验，研究了接合温度和持续时间对接合界面微观结构和机械性能的影响。结果表明，将 HIP 温度从 980 ℃ 降到 850 ℃ 会显著减少 W/Fe 反应层的厚度。在温度为 900 和 850 ℃ 时，反应层厚度的减少使得接合界面没有反应层。然而，随着温度的降低，剪切强度会出现先上升后下降的情况，在 950 °C 时达到的最大剪切强度可达 322 兆帕。在 950 °C 温度下延长键合时间会导致 W/Fe 反应层从 Fe2W 快速转变为 Fe3W3C，从而削弱整体键合性能。相反，在 900 和 850 °C 温度下延长键合时间对界面微观结构和键合强度的影响都很小。
{"title":"Effect of HIP bonding temperature and duration on the interfacial microstructure and mechanical properties of W/steel joint with an Fe interlayer","authors":"Pan Huang, Jiming Chen, Yiming Wang, Yanyu Chen, Zhengxing Wei, Shiyu Cui, Yi Zhou, Qian Li, Pinghuai Wang","doi":"10.1016/j.fusengdes.2024.114685","DOIUrl":"10.1016/j.fusengdes.2024.114685","url":null,"abstract":"<div><div>HIP experiments were conducted at temperatures of 950, 900, and 850 °C for durations of 60, 135, and 240 min respectively in this study, the effect of bonding temperature and duration on the interfacial microstructure and mechanical properties of the joint was investigated. The results demonstrate that reducing the HIP temperature from 980 to 850 °C leads to a significant decrease in the thickness of the W/Fe reaction layer. This reduction enables bonding interfaces without reaction layer at temperatures of 900 and 850 °C. However, as the temperature decreases, there is an initial increase followed by a subsequent decrease in shear strength with a maximum shear strength achieved at 950 °C reaching up to 322 MPa. Prolonging the bonding duration at a temperature of 950 °C results in a rapid transition of W/Fe reaction layer from Fe<sub>2</sub>W to Fe<sub>3</sub>W<sub>3</sub>C which weakens the overall bonding performance. Conversely, increasing the bonding duration at temperatures of 900 and 850 °C has minimal impact on both interfacial microstructure and bonding strength.</div></div>","PeriodicalId":55133,"journal":{"name":"Fusion Engineering and Design","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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