Tritium Issues in Next Step Devices

Skinner, C.H.; Federici, G.

doi:10.1007/978-1-4419-8696-2_51

Cited by 6 publications

(3 citation statements)

References 13 publications

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“…Up to 87% of the codeposited tritium has been thermally desorbed from tile samples from the Joint European Torus (JET) and the Tokamak Fusion Test Reactor (TFTR) in laboratory experiments [12]. The technique is attractive for tritium removal in a next-step DT device since it avoids the use of oxidation, the associated deconditioning of the plasma facing surfaces and expense of processing large quantities of tritium oxide [13,14]. Although designed for tritium removal, this approach offers an opportunity to study in microscopic detail the thermomechanical response of tokamak generated codeposits to transient high heat fluxes.…”

Section: Introductionmentioning

confidence: 99%

Thermal Response of Tritiated Codeposits from JET and TFTR to Transient Heat Pulses

et al. 2003

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Section: Introductionmentioning

confidence: 99%

Thermal Response of Tritiated Codeposits from JET and TFTR to Transient Heat Pulses

et al. 2003

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Section: Introductionmentioning

confidence: 99%

Thermal Response of Tritiated Co-deposits from JET and TFTR to Transient Heat Pulses

Skinner¹,

Bekrisl²,

Coad³

et al. 2002

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Abstract.High heat flux interactions with plasma facing components have been studied at microscopic scales. The beam from a continuous wave neodymium laser was scanned at high speed over the surface of graphite and carbon fiber composite tiles that had been retrieved from TFTR and JET after DT plasma operations. The tiles have a surface layer of amorphous hydrogenated carbon that was codeposited during plasma operations and laser scanning has released more than 80% of the codeposited tritium. The temperature rise of the codeposit was much higher than that of the manufactured material and showed an extended time history. The peak temperature varied dramatically (e.g. 1436 °C compared to > 2300 °C) indicating strong variations in the thermal conductivity to the substrate. A digital microscope imaged the codeposit before, during and after the interaction with the laser and revealed 100-micron scale hot spots during the interaction. Heat pulse durations of order 100 ms resulted in brittle destruction and material loss from the surface, whilst a duration of ≈10 ms showed minimal changes to the codeposit. These results shot that reliable predictions for the response of deposition areas to off-normal events such as ELMs and disruptions in next step devices need to be based on experiments with tokamak generated codeposits

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“…The survival of plasma facing materials under ELMs, disruptions and vertical displacement events (VDEs), and the control of the tritium inventory are related challenges that must be met for magnetic fusion to achieve its promise as an attractive, environmentally acceptable energy source [2]. Carbon based materials have superior thermomechanical properties and do not melt (they sublime), however they cause high levels of tritium retention by codeposition with eroded carbon that would severely curtail plasma operations [3,4] in a next-step device with carbon plasma facing components.…”

Section: Introductionmentioning

confidence: 99%

High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser

Skinner¹,

Gentile²,

Hassanein³

2002

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A new technique for studying high heat flux interactions with plasma facing components is presented. The beam from a continuous wave 300 W neodymium laser was focussed to 80 W/mm 2 and scanned at high speed over the surface of carbon tiles. These tiles were previously used in the TFTR inner limiter and have a surface layer of amorphous hydrogenated carbon that was codeposited during plasma operations. Laser scanning released up to 84% of the codeposited tritium. The temperature rise of the codeposit on the tiles was significantly higher than that of the manufactured material. In one experiment, the codeposit surface temperature rose to 1,770°C while for the same conditions, the manufactured surface increased to only 1,080 °C. The peak temperature did not follow the usual square-root dependence on heat pulse duration. Durations of order 100 ms resulted in brittle destruction and material loss from the surface, while a duration of ≈10 ms showed minimal change. A digital microscope imaged the codeposit before, during and after the interaction with the laser and revealed hot spots on a 100-micron scale. These results will be compared to analytic modeling and are relevant to the response of plasma facing components to disruptions and vertical displacement events (VDEs) in next-step magnetic fusion devices.

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Tritium Issues in Next Step Devices

Cited by 6 publications

References 13 publications

Thermal Response of Tritiated Codeposits from JET and TFTR to Transient Heat Pulses

Thermal Response of Tritiated Codeposits from JET and TFTR to Transient Heat Pulses

Thermal Response of Tritiated Co-deposits from JET and TFTR to Transient Heat Pulses

High Heat Flux Interactions and Tritium Removal from Plasma Facing Components by a Scanning Laser

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