Article
Physics, Multidisciplinary
Anna Widdowson, J. Paul Coad, Yevhen Zayachuk, Ionut Jepu, Eduardo Alves, Norberto Catarino, Victoria Corregidor, Matej Mayer, Stepan Krat, Jari Likonen, Kenichiro Mizohata, Chris Rowley, Miroslaw Zlobinski, Marek Rubel, David Douai, Kalle Heinola, Tom Wauters, Laura Dittrich, Sunwoo Moon, Per Petersson, Aleksandra Baron-Wiechec, Liga Avotina
Summary: Based on the most comprehensive ex situ fuel retention data set on JET PFCs from the 2015-2016 ILW3 operating period, an assessment of the tritium inventory in plasma facing components (PFC) during JET T and deuterium-tritium (DT) operations is presented. The results show a small global fuel retention, with the inner divertor having the highest fuel retention. The calculated T inventory in PFCs at the end of JET operations is important for accountancy, clean-up efficacy, and waste liability assessments.
Article
Physics, Fluids & Plasmas
F. R. Urgorri, C. Moreno, D. Rapisarda
Summary: Understanding and predicting tritium transport is crucial for the design of fusion power plants. This study used 2D finite volume methods to analyze tritium permeation through cooling plates, considering various parameters affecting breeding blanket performance. Results showed that 1D model accuracy and system level model accuracy are strongly dependent on the permeation regime, emphasizing the importance of form factors in increasing precision.
Article
Physics, Fluids & Plasmas
Byung Chul Kim
Summary: The neutronic response of the materials in the Korean fusion DEMOnstration reactor (K-DEMO) is crucial for its conceptual design. Neutronic damage is a major limiting factor for the lifetime of in-vessel components (IVCs) placed in the extreme neutron irradiation field. The analysis of the neutronic response of IVCs allows the quantification of neutron wall loading (NWL) to assess the tritium supply and thermal energy transfer. The design optimization of K-DEMO will continue based on the response analysis.
Article
Thermodynamics
F. R. Urgorri, C. Moreno, I. Fernandez-Berceruelo, D. Rapisarda
Summary: In PbLi based breeding blanket concepts, tritium transport and MHD interactions play a crucial role in the self-sustainability and safety of the plant. Numerical studies on permeation through walls and MHD forces provide insights into the mechanisms of tritium transport.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Materials Science, Multidisciplinary
Y. Gasparyan, D. Bachurina, V. Efimov, J. Gurova, F. Podolyako, N. Sergeev, I. Sorokin, A. Suchkov, N. Bobyr, I. Kozlov, E. Kulikova, A. Spitsyn
Summary: The study investigates the use of fully reduced activation brazing alloy and tantalum intermediate layer for joining tungsten and reduced-activation ferritic-martensitic steel. The deuterium retention in the joints and separate elements was studied, and it was observed that an acceptable deuterium concentration can be achieved under specific operating conditions but higher pressure leads to joint failure.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Physics, Fluids & Plasmas
D. Rapisarda, I Fernandez-Berceruelo, A. Garcia, J. M. Garcia, B. Garcinuno, M. Gonzalez, C. Moreno, I Palermo, F. R. Urgorri, A. Ibarra
Summary: CIEMAT has been leading the development of an advanced dual coolant lithium lead breeding blanket for use in the realistic DEMO scenario. The design includes tritium extraction system and simulations. Recently, a new BB concept based on the DCLL technology is being developed to increase plant net efficiency.
Article
Nuclear Science & Technology
Gandolfo Alessandro Spagnuolo, Rodrigo Arredondo, Lorenzo Virgilio Boccaccini, Matti Coleman, Ion Cristescu, Gianfranco Federici, Fabrizio Franza, Belit Garcinuno, Carlos Moreno, David Rapisarda, Fernando Roca Urgorri, Marco Utili
Summary: Under the EUROfusion framework, two reactor architectures are being developed for the EU DEMO, one based on the Water Cooled Lithium Lead concept and the other on the Helium Cooled Pebble Bed concept. These two variants result in different reactor designs due to the use of different coolants and neutron multipliers, necessitating tailored tritium management systems and technologies.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Physics, Multidisciplinary
E. Pajuste, A. S. Teimane, G. Kizane, L. Avotina, M. Halitovs, A. Lescinskis, A. Vitins, P. Kalnina, E. Lagzdina, R. J. Zabolockis
Summary: The ITER-Like-Wall project at JET examines plasma facing materials for ITER, including bulk metals and coatings, analyzing tritium retention and behavior through various methods to understand its distribution and accumulation in the vacuum vessel.
Article
Nuclear Science & Technology
Yasunori Iwai, Yuki Edao, Rie Kurata, Kanetsugu Isobe
Summary: In the JA DEMO project, the deuterium-tritium fuel is supplied by a combination of gas puff, pellet injection, and neutral beam injection. The fuel cycle becomes steadier, transitioning towards a continuous processing system. It is necessary to establish a fuel cycle to balance tritium in the facility.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Nuclear Science & Technology
M. L. Richiusa, P. Ireland, F. Maviglia, J. Nicholas, Z. Vizvary
Summary: This article presents the progress in engineering modeling of plasma-facing material phase change under high heat flux in the EU-DEMO first wall protection framework, using the COMSOL Multiphysics software.
FUSION ENGINEERING AND DESIGN
(2023)
Article
Nuclear Science & Technology
P. A. Di Maio, R. Burlon, G. Mazzone, A. Quartararo, E. Vallone, J. H. You
Summary: In the study of the DEMO divertor cooling system, serious critical issues such as intolerable total pressure drop and insufficient margin against CHF onset within all the PFU channels were identified. An optimization study was conducted to investigate potential improvements in thermal-hydraulic performance of the PFCs cooling circuit, focusing on the inlet manifold branch. The study identified the most effective cooling circuit configuration to fulfill pressure drop requirements and increase the CHF margin within the PFU channels.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Energy & Fuels
H. L. Swami, Deepak Sharma, A. N. Mistry, C. Danani, P. Chaudhuri, R. Srinivasan
Summary: The Helium cooled dual breeder (HCDB) blanket concept, designed for the Indian DEMO fusion reactor, utilizes innovative design to enhance heat extraction efficiency and eliminate toxic beryllium usage. Its unique structure demonstrates potential as a tritium breeding blanket for Indian demonstration nuclear fusion power plants.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Nuclear Science & Technology
Guo-Jian Niu, Gakushi Kawamura, Qian Xu, Tao He, Fei-Fei Nian, Rong Wang, Zhong-Shi Yang, Guang-Nan Luo
Summary: This study investigates the deposition behavior of tritium on dust using a hybrid particle simulation method. The results indicate that the size and specific surface area of the dust grains, as well as the electrostatic sheath induced by the dust, significantly influence the deposition and retention behavior of tritium.
NUCLEAR MATERIALS AND ENERGY
(2022)
Article
Nuclear Science & Technology
Yudong Lu, Minyou Ye, Guangming Zhou, Francisco A. Hernandez, Jaakko Leppanen, Yuan Hu
Summary: Innovative water-cooled lead ceramic breeder blanket concepts are being developed at the Karlsruhe Institute of Technology to explore alternative options for the European demonstration fusion power plant. Research also indicates that water-cooled blankets need to improve tritium breeding capacity to meet the vital function of tritium self-sufficiency.
NUCLEAR MATERIALS AND ENERGY
(2021)
Article
Engineering, Electrical & Electronic
Mauro Dalla Palma, Monica Spolaore
Summary: The surface eroding thermocouples are developed for measuring temperatures and heat fluxes in plasma-facing components of fusion machines, with fast response and robust design. The improved sensor performance is achieved by enhancing the thermal contact surface between the divertor mono-block and the thermocouple carrier body. The measurement errors and installation at different poloidal positions are discussed, providing useful local information for studying divertor physics and assisting controlled terminations of plasma discharges.
IEEE SENSORS JOURNAL
(2021)
Article
Nanoscience & Nanotechnology
Asanka Weerasinghe, Enrique Martinez, Brian D. Wirth, Dimitrios Maroudas
Summary: We conducted a systematic computational analysis of the mechanical behavior of tungsten in plasma-facing components (PFCs), focusing on the effects of void and helium (He) bubble defects on the mechanical response beyond the elastic regime. Our findings suggest that defective tungsten undergoes substantial softening with increasing matrix porosity and He atomic content, resulting in a decrease in the yield strength of tungsten in a monotonically decreasing fashion. We also observed that the structural response of PFC tungsten near the yield point is initiated by the emission of dislocation loops from bubble/matrix interfaces, followed by gliding and growth of these loops and reactions to form dislocations.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Physics, Fluids & Plasmas
Chao-Shou Chen, Dwaipayan Dasgupta, Asanka Weerasinghe, Karl D. D. Hammond, Brian D. D. Wirth, Dimitrios Maroudas
Summary: We conducted a simulation study on the effect of He-irradiation-induced surface vacancy-adatom pair formation on the surface morphological evolution of plasma-facing component (PFC) tungsten. Our analysis was based on a self-consistent dynamical simulation according to a surface evolution model developed using a hierarchical multiscale modeling strategy. The model considered the flux of surface adatoms generated by surface vacancy-adatom pair formation, which contributed to the anisotropic growth of surface nanostructural features. We explored the dependence of the PFC surface morphological response on surface temperature and He ion incident flux, and compared the predicted surface morphologies with experimental observations.
Editorial Material
Multidisciplinary Sciences
Patrick H. Diamond, Rameswar Singh, Ting Long, Rongjie Hong, Rui Ke, Zheng Yan, Mingyun Cao, George R. Tynan
Summary: The electric field profile structure, especially its shear, is an order parameter for the edge plasma that characterizes different confinement regimes. The theoretical developments and lessons learned from H-mode studies are applied to the shear layer collapse paradigm for the onset of density limit phenomena. Recent experimental results on edge shear layers and density limit phenomenology are summarized and discussed in the context of L -> H transition physics.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Nuclear Science & Technology
M. J. Baldwin, M. I. Patino, B. Schwendeman, M. Simmonds, A. Zaloznik, D. Nishijima, G. Tynan
Summary: Annealing of tungsten-deuterium co-deposits at different temperatures induces changes in desorptive release behavior and crystal structure. The study examines the changes in co-deposits through annealing, X-ray diffraction analysis, D plasma exposure, scanning electron microscopy, and thermal desorption mass spectrometry.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Materials Science, Multidisciplinary
Pieterjan Robbe, Sophie Blondel, Tiernan A. Casey, Ane Lasa, Khachik Sargsyan, Brian D. Wirth, Habib N. Najm
Summary: We develop a comprehensive global sensitivity analysis framework for a connected multiphysics model used in predicting the changes in material properties and surface morphology of plasma-facing components in fusion reactors. The model incorporates F-TRIDYN, a particle dynamics simulator, for helium implantation profile prediction, and Xolotl, a cluster dynamics simulator, for subsurface helium gas bubble growth and evolution prediction. To ensure the tractability of the sensitivity analysis, we construct a sparse, high-dimensional polynomial chaos expansion surrogate model for each output parameter of interest, enabling efficient extraction of sensitivity information. The sensitivity analysis is conducted for two different problem settings representing ITER-like conditions and conditions inside the PISCES-A linear plasma device. We provide a systematic comparison of significant parameters for F-TRIDYN, Xolotl, and the coupled model, and discuss the physical interpretation of the results.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
L. Yang, B. D. Wirth
Summary: The stability and structure of low sigma value tilt grain boundaries in UO2 were investigated using molecular statics/dynamics simulations. Density functional theory (DFT + U) calculations showed that a defective triangle-like pattern in the E5(310) boundary was preferred over an oxygen-ring pattern. The incorporation energy profiles indicated that Xe interstitial sites at grain boundaries were energetically favorable compared to the bulk, while Xe incorporation in some Schottky defects or uranium vacancy sites at certain boundaries was energetically unfavorable. However, in general, Xe and its complexes tended to segregate to grain boundaries.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Nuclear Science & Technology
M. I. Patino, R. P. Doerner, T. Schwarz-Selinger, M. J. Baldwin, G. R. Tynan
Summary: A temperature dependent study was conducted to investigate the retention of helium in tungsten fuzz layers, providing insights into the fuzz formation process and its relation to trapped helium. The retention of 3He in the fuzz layer and bulk substrate was measured, and the total retention of (3He+4He) due to sequential exposure was inferred. The results showed that helium retention in the fuzz layer was independent of temperature, but a significant increase in helium retention was observed in the bulk near the fuzz formation temperature threshold.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Engineering, Electrical & Electronic
S. Balachandran, P. Xu, P. Dhakal, M. Carl, R. P. Walsh, P. J. Lee
Summary: High purity niobium (Nb) is an important material for microwave applications in large-scale accelerators and nano-scale quantum computing. It exhibits high thermal conductivity and low resistivity essential for high performance at temperatures ranging from 0.01 to 4.0 K. The presence of interstitial impurities such as O, N, H, and C affects the resistivity and thermal conductivity, significantly impacting Nb's thermal performance at temperatures above 2.0 K. The residual resistivity ratio (RRR) is used to estimate the impurity content of fully recrystallized Nb. However, complete re-crystallization is challenging, and dislocations and their structures contribute to strong phonon scattering, affecting Nb's thermal performance. This study investigates the degradation of thermal conductivity and RRR in high purity Nb single crystals with fixed impurity, varying strain, and dislocation content levels, and the experimental data is fitting using the Boltzmann transport equation incorporating dislocation density.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Engineering, Electrical & Electronic
Shreyas Balachandran, David B. Smathers, Jiman Kim, Kihong Sim, Peter J. Lee
Summary: Uniform co-deformation of Nb, Ta, and their alloys in a Cu matrix is crucial for the performance yield of Nb3Sn conductors. However, there are instabilities during extrusion and drawing due to multiple factors. This study presents a method to quantify interface roughness, which can provide a better understanding of variability. The procedure developed can optimize the wire architecture for next-generation high-field magnets.
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
(2023)
Article
Materials Science, Multidisciplinary
G. Pastore, N. Militello, S. Blondel, B. D. Wirth
Summary: We simulated the evolution of intra-granular fission gas bubbles in UO2 using two models and compared the results to experimental data. The models showed excellent agreement with each other and with the experimental trends of bubble average size and number density. The calculated results either matched the data well or had errors within consistent uncertainties.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Nuclear Science & Technology
Seok Bin Seo, Brian D. Wirth
Summary: This paper presents a systematic sensitivity analysis of the diffusivity parameters of cesium and strontium inside TRISO fuel particle and their dependence on irradiation and high temperature annealing conditions. The BISON fuel performance code was used to model the base irradiation and the high temperature tests performed within the AGR-1 experiment. The sensitivity analysis results quantified the contributions of the various diffusion parameters to BISON predictions of Cs and Sr release from compacts exposed to a number of different irradiation and thermal conditions.
NUCLEAR ENGINEERING AND DESIGN
(2023)
Review
Materials Science, Multidisciplinary
Ishtiaque Karim Robin, Tim Graning, Ying Yang, Syeda Bushra Haider, Eric Andrew Lass, Yutai Katoh, Steven John Zinkle
Summary: This study investigates solid-state bonding techniques, with a focus on diffusion bonding, as an effective method for establishing engineering bonds. Diffusion bonding offers a lower temperature process and can handle materials with large differences in melting temperature. The insights from this research can be applied to various industries, enabling advanced and efficient design.
Article
Materials Science, Multidisciplinary
Yao Li, Miao Song, Pengcheng Zhu, Yan-Ru Lin, Zehui Qi, Yajie Zhao, Samara Levine, Steven J. Zinkle
Summary: This study introduces the flash electropolishing technique as a solution to remove FIB-induced damages from TEM samples. The technique has been successfully applied to various materials with adjustable parameters. It offers a promising solution to the challenges posed by FIB-induced damages in the preparation of TEM samples.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Neal D. Gaffin, Kelsa B. Palomares, Justin L. Milner, Steven J. Zinkle
Summary: Ceramic-metallic composite (cermet) fuel forms are promising for nuclear thermal propulsion (NTP), and spark plasma sintering improves the microstructural characteristics. High density composites with excellent particle-matrix interfaces can be fabricated using a new lab-scale particle coating method.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Taylor G. Duffin, Kelsa B. Palomares, Steven J. Zinkle
Summary: Ceramic-metallic (cermet) fuels show promise for space nuclear thermal propulsion systems. This study examines the hydrogen compatibility of molybdenum matrix cermets with yttria stabilized zirconia (YSZ) particles at extreme temperatures. The results show that the cermet exhibits acceptable mass loss and remains stable under high temperature hydrogen exposure.
JOURNAL OF NUCLEAR MATERIALS
(2023)
