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Mohamad Abdallah, Bjorn Cole, Daniel Clark, Jonas Kessing, Felipe Novais, Jonathan Naish, Paul Humrickhouse
Luigi Candido, Luke Taylor-King, Colin Baus, Christian Day, Italo Godoy-Morison, John McGrady, Minoru Jimma, Kyosuke Namba, Jonas Schwenzer, Tim Teichmann, et al.
Christopher J. Koch, Nasiba Abdurakhmanova, Natalie Wieber, Tim Krentz, Tyler Guin, Dale A. Hitchcock
Tatyana Sizyuk
Self-consistently integrated models for deuterium plasma interactions with plasma-facing materials (PFMs) have been developed and integrated into the upgraded ITMC-DYN+ simulation package. These models capture critical processes such as bubble and blister growth from nanocavities, blister bursting, defects formation induced by deuterium supersaturation, and changes in deuterium diffusivity resulting from microstructural evolution. Benchmarking against experimental data on deuterium retention and defect evolution in tungsten demonstrates that our integrated approach accurately explains a range of experimental observations for the first time. Key findings include: (a) the dynamics of bubble and blister growth and their impact on trapping site accumulation, (b) the combined effects of cavity growth, bursting, and surrounding dislocation networks, (c) the formation of a deuterium supersaturated surface layer (DSSL), (d) the influence of DSSL on deuterium diffusivity and bulk transport, and (e) differences in deuterium retention between pre-damaged tungsten and tungsten simultaneously irradiated by deuterium and neutrons. This self-consistent analysis reveals synergistic effects of blistering and DSSL formation on deuterium retention and transport in tungsten under varying temperatures and damage rates.
Yevgen Chikhray, Saulet Askerbekov, Timur Kulsartov, Asset Shaimerdenov, Magzhan Aitkulov, Zhanar Bugybay, Assyl Akhanov
Hugh Boniface, Amir Motamed Dashliborun, Jonas Caspar Schwenzer, Tim Teichmann, Todd Whitehorne
C. Weaver, J. Dark, R. Delaporte-Mathurin, K.B. Woller
Daniel Morrall, Tim Krentz, Natalie Wieber, Gavin Mattingly, Dale Hitchcock
Jie Zhang, Florian Koechl, Alexei R Polevoi, Clarisse Bourdelle, Sunhee Kim, Alberto Loarte, Simon D Pinches, Ge Zhuang
The enhanced confinement of tokamak plasmas (H-mode) makes it a preferred regime for achieving fusion power production goals in future devices such as ITER. Nevertheless, low confinement mode (L-mode) remains worthy to investigate in reactor relevant conditions, primarily due to no/reduced requirements for ELM and divertor heat load control. In this regard, this study aims at exploring a new potential approach to maximise the achievable fusion gain Qfus. This approach attempts to increase the core density with enhanced pellet fuelling and then investigates the feasibility of high Qfus L-mode operation in ITER. The JINTRAC integrated modelling suite has been employed for core-edge transport and source modelling, using the HPI2 module for pellet fuelling. In some of the scenarios considered, the core density reaches up to ∼185% of the Greenwald density, nGW, with edge densities approaching nGW, motivated by recent re-evaluations of the density limit that suggest a power-dependent threshold. We compare core transport modelling results obtained by applying the semi-empirical Bohm-gyro-Bohm (BgB) or the quasi-linear gyrokinetic TGLF-SAT2 anomalous transport models, with interpretive vs. predictive impurity transport modelling, and pellet fuelling describing continuous vs. discrete particle sources. The core plasma confinement of high-density L-mode operation in ITER predicted by the TGLF-SAT2 model is significantly better than that predicted by the BgB model, resulting in a significantly improved Qfus. Fusion performance metrics, including Pfus and Qfus, exhibit only minor changes when switching from the interpretive impurity model to the predictive SANCO model, and/or from the continuous ad-hoc pellet model to the discrete HPI2 pellet model. The highest Qfus value predicted in the ITER high-density L-mode simulations is ~ 4, with indications that further improvement may be limited by increased transport associated with electro-magnetic turbulence at elevated plasma beta. This integrated modelling prediction demonstrates the potential of improved Qfus L-mode operation in ITER and future fusion devices, while exploring its boundary.
Ting Wang, Arkadi Kreter, Peng Bi, Hanqing Wang, Y. Mao, Hao Wang, Yue Yuan, Long Cheng, Li-Qun Shi, Jun Tang, et al.
Controlling hydrogen isotope retention is a critical challenge for plasma-facing materials (PFMs) in fusion reactors. Chemical vapor deposited tungsten (CVD-W), featuring columnar grain structures, has attracted increasing attention as a candidate PFM. However, its surface blistering and deuterium (D) retention behavior under fusion-relevant, complex irradiation conditions remain insufficiently understood. In this work, CVD-W and ITER-like forged W both with grains elongated normal to the exposed surface were irradiated with pure D and mixed D+5% He plasma, with and without prior W self-ion irradiation at damage levels of 0.2 and 2 dpa. Compared with ITER-like W, CVD-W exhibits substantially enhanced tolerance to D-induced surface blister formation and markedly reduced D retention under pure D plasma exposure. Regardless of displacement damage, He seeding, or their combination, CVD-W consistently retains less D than ITER-like W across all irradiation sequences studied. This persistently low D retention in CVD-W is primarily associated with its lower defect density (e.g. fewer grain boundaries) and a blister-resistant <001> surface texture that limits blister-related D trapping. Furthermore, displacement damage and He seeding effectively suppress surface blistering, but exert opposing individual effects on D retention in both materials. Their combined effect shows a clear dependence on D fluence and material microstructure. This work highlights the advantages of CVD-W in suppressing hydrogen isotope retention under complex irradiation environments and provides valuable insights for the selection and microstructural design of advanced PFMs with improved resistance to hydrogen-induced blistering and reduced retention.
Kai Huang, Peng Ran, Shixin Ruan, Yongpeng Lyu, Teng Wang, Bin Zhang, Zhaoting Huang
Natalie Wieber, Timothy Krentz, Anastasia Mullins, Dorian Balch, Joseph Ronevich
Yuya Ando, Yuto Murata, Takuya Nagasaka, Teppei Otsuka
James Davis, Sellathurai Suppiah, Ezekial Unterberg, Donald Ryland, Peter Stangeby
J. Northall, E. H. Norris
Yuki Edao, Katsumi Sato
Mariagrazia Romano, Michele Fincato, Paolo Innocente, Christian Avanzato, Luca Balbinot, Andrea Belpane
A. A. Stepanenko, Yu. M. Gasparyan
Laser-induced-desorption quadrupole-mass-spectrometry (LID-QMS) diagnostics is considered as one of the candidate methods for the remote control of tritium inventory in the ITER first wall. Studies involving LID-QMS generally assume the circular shape of the laser spot on the analyzed surface. At the same time, the diagnostics laser source cannot be always positioned so as to irradiate tokamak tiles under normal angles, which results in the laser spot shape differing from the circular one. In this contribution, we analyze the tritium removal process under sample irradiation by an elliptic Gaussian laser beam, extending the results of our previous analysis [Stepanenko, Gasparyan, Physica Scripta 99 (8), 085604 (2025)]. The thermal desorption model governing the heat transport and tritium removal from the solid is formulated. The new analytical expression describing the sample temperature dynamics is derived. The developed model is used to examine the impact of the laser beam/spot ellipticity on the tritium desorption process from a tungsten sample. The conditions, under which the elliptic beam can be approximated with the circular one for the rapid assessment of the amount of desorbed tritium, are assessed.
Rishi Pillai, Debashish Sur, Severine Cambier, Adam Willoughby, Tracie Lowe, Youyang Zhao, Amanda Bye, Susana Reyes
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