The pre-concept design of the DEMO tritium, matter injection and vacuum systems

Day, Christian; Battes, K.; Butler, B.; Davies, S.; Farina, Luca; Frattolillo, A.; George, Robert William; Giegerich, T.; Hanke, S.; Härtl, T.; Igitkhanov, Yuri; Jackson, Thomas; Jayasekera, N.; Kathage, Y.; Lang, P. T.; Lawless, R.; Luo, Xueli; Neugebauer, C.; Ploeckl, B.; Santucci, Alessia; Schwenzer, J.; Teichmann, Tim; Tijssen, Teuntje; Tosti, Silvano; Varoutis, S.; Cortes, Alejandro Vazquez

doi:10.1016/j.fusengdes.2022.113139

Cited by 30 publications

(14 citation statements)

References 65 publications

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“…However, a beneficial effect of the argon source being situated in the pedestal gradient region is expected in DEMO due to the neoclassical outward drift at conditions of high pedestal ion temperature [23]. The impurity doping scheme would have to be integrated into the complete DEMO fuel cycle, which includes plasma enhancement gases like argon [24,25], and into the overall impurity seeding strategy [3,26]. Fast Ar pumping will help to reduce the less efficient radiation contribution related to Ar recycling, thus maximizing δP rad /δZ eff .…”

Section: Discussionmentioning

confidence: 99%

Argon doped pellets for fast and efficient radiative power removal in ASDEX Upgrade

et al. 2022

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Argon doped deuterium pellets with about 1 per mille Ar atomic fraction have been injected into ASDEX Upgrade H-mode discharges and demonstrate fast and efficient power removal from the outer plasma region. Bolometer views directly on the pellet and in its very close vicinity observe a strong, non-toroidally symmetric radiation pattern on a fast, sub-ms time scale. This is explained by the ionisation process of the delivered Ar neutrals, leading to non-Coronal radiation by intermediate ionisation stages until the equilibrium He like stage is reached. Subsequently, a toroidally symmetric radiation increase is observed with a fast initial decay time of about 20 ms consistent with the radial particle transport time scale for a source located in the outer plasma. Subsequently, a radiation pattern related to Ar recycling develops comparable to Ar midplane gas puffing which decays with the Ar divertor pumping time of about 200 ms. The energy radiated around each pellet is described by the radiative potential of Ar evaluated for non-Coronal conditions with the ablation time as the relevant time scale. A factor 4 too low radiated energy is obtained by this simple model, which could be explained by stronger deviations from Corona equilibrium and plasma parameter variations in the vicinity of the pellet. Injection of Ar-doped pellets into a no-ELM QCE H-mode discharge showed no triggering of ELMs by the pellet. Advantages of the pellet seeding scheme are the faster reaction time of the radiation compared to gas puffing, which may be important to counter-act transient re-attachment in ITER or in a reactor and an elevated radiative efficiency in the outer core plasma due to non-Corona effects.

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Section: Discussionmentioning

confidence: 99%

Argon doped pellets for fast and efficient radiative power removal in ASDEX Upgrade

et al. 2022

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“…[104,105] The OFC, by contrast, serves to efficiently extract the bred tritium, which includes breeding blankets, and the coolant purification and tritium extraction and recovery systems. [106] Thus, the EPS, ISS, and SDS are key systems for both loops.…”

Section: D-t Fuel Cycle Of a Fusion Reactormentioning

confidence: 99%

“…Since only deuterium and tritium must be recycled, the exhaust gas must be recovered, refined, isotopically separated, and refueled to maintain the fuel efficiency. [ 106 ] The off‐gases from the torus collected in cryopumps are moved by the roughing pump into the EPS. The EPS cleans up the exhaust gas and removes plasma enhancement gases and other impurities from the hydrogen isotopes.…”

Section: Importance Of Fusion Energy Tritium Inventories and Deuteriu...mentioning

confidence: 99%

Recent Progress in Functional Nanomaterials towards the Storage, Separation, and Removal of Tritium

et al. 2023

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Tritium is a sustainable next‐generation prime fuel for generating nuclear energy through fusion reactions to fulfill the increasing global energy demand. Owing to the scarcity–high demand tradeoff, tritium must be bred inside a fusion reactor to ensure sustainability and must therefore be separated from its isotopes (protium and deuterium) in pure form, stored safely, and supplied on demand. Existing multistage isotope separation technologies exhibit low separation efficiency and require intensive energy inputs and large capital investments. Furthermore, tritium‐contaminated heavy water constitutes a major fraction of nuclear waste, and accidents like the one at Fukushima Daiichi leave behind thousands of tons of diluted tritiated water, whose removal is beneficial from an environmental point of view. In this review, we discuss the recent progress and main research trends in hydrogen isotope storage and separation by focusing on the use of metal hydride (e.g., intermetallic, and high‐entropy alloys), porous (e.g., zeolites and metal organic frameworks (MOFs)), and 2‐D layered (e.g., graphene, hexagonal boron nitride (h‐BN), and MXenes) materials to separate and store tritium based on their diverse functionalities. Finally, the challenges and future directions for implementing tritium storage and separation are summarized in the reviewed materials.This article is protected by copyright. All rights reserved

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“…The fuel cycle of a fusion power plant is responsible for refueling the plasma, and for reprocessing and storing the stream coming from the plasma chamber along with all the tritiated effluents present in the plant. During the pre-concept design phase, Day et al [ 14 ] developed a novel three-loop-based architecture for the DEMO fuel cycle aiming at minimizing tritium inventory in the system, promoting a continuous operation, and avoiding hold-ups of tritium in its processes.…”

Section: The Tritium Conditioning Systemmentioning

confidence: 99%

Experimental and Numerical Analysis of a Pd–Ag Membrane Unit for Hydrogen Isotope Recovery in a Solid Blanket

Narcisi,

Tamborrini,

Farina

et al. 2023

Membranes

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The interest of the fusion community in Pd–Ag membranes has grown in the last decades due to the high value of hydrogen permeability and the possibility of continuous operation, making it a promising technology when a gaseous stream of hydrogen isotopes must be recovered and separated from other impurities. This is the case of the Tritium Conditioning System (TCS) of the European fusion power plant demonstrator, called DEMO. This paper presents an experimental and numerical activity aimed at (i) assessing the Pd–Ag permeator performance under TCS-relevant conditions, (ii) validating a numerical tool for scale-up purposes, and (iii) carrying out a preliminary design of a TCS based on Pd–Ag membranes. Experiments were performed by feeding the membrane with a He–H2 gas mixture in a specific feed flow rate ranging from 85.4 to 427.2 mol h−1 m−2. A satisfactory agreement between experiments and simulations was obtained over a wide range of compositions, showing a root mean squared relative error of 2.3%. The experiments also recognized the Pd–Ag permeator as a promising technology for the DEMO TCS under the identified conditions. The scale-up procedure ended with a preliminary sizing of the system, relying on multi-tube permeators with an overall number ranging between 150 and 80 membranes in lengths of 500 and 1000 mm each.

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The pre-concept design of the DEMO tritium, matter injection and vacuum systems

Cited by 30 publications

References 65 publications

Argon doped pellets for fast and efficient radiative power removal in ASDEX Upgrade

Argon doped pellets for fast and efficient radiative power removal in ASDEX Upgrade

Recent Progress in Functional Nanomaterials towards the Storage, Separation, and Removal of Tritium

Experimental and Numerical Analysis of a Pd–Ag Membrane Unit for Hydrogen Isotope Recovery in a Solid Blanket

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