Protection of nuclear graphite toward fluoride molten salt by glassy carbon deposit

Bernardet, Véronique; Gomès, Séverine; Delpeux, Sandrine; Dubois, Marc; Guérin, Katia; Avignant, D.; Renaudin, Guillaume; Duclaux, Laurent

doi:10.1016/j.jnucmat.2008.11.032

Cited by 48 publications

(14 citation statements)

References 20 publications

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“…Its combined resistance to high temperature, corrosion and wear, together with low density, impermeability to gases and liquids makes glassy carbon more useful in many industrial applications such as vacuum evaporation sources, chemical containment, zone-refinement crucibles and more interestingly encapsulation of nuclear fuel elements [1], [4]. GC has also been proposed to be used as a protective layer on the graphite reactor core surface in molten salt breeder reactors [5].…”

Section: Introductionmentioning

confidence: 99%

Annealing effects on the migration of ion-implanted cadmium in glassy carbon

Hlatshwayo

Sebitla

Njoroge

et al. 2017

Nuclear Instruments and Methods in Physics Research Section B:

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The migration behavior of cadmium (Cd) implanted into glassy carbon and the effects of annealing on radiation damage introduced by ion implantation were investigated. The glassy carbon substrates were implanted with Cd at a dose of 2×10 16 ions/cm 2 and energy of 360 keV. The implantation was performed at room temperature (RT), 430 °C and 600 °C. The RT implanted samples were isochronally annealed in vacuum at 350, 500 and 600 °C for 1 hour and isothermally annealed at 350 °C up to 4 hours. The as-implanted and annealed samples were characterized by Raman spectroscopy and Rutherford backscattering spectrometry (RBS). Raman results revealed that implantation at room temperature amorphized the glassy carbon structure while high temperature implantations resulted in slightly less radiation damage. Isochronal annealing of the RT implanted samples resulted in some recrystallization as a function of increasing temperature. The original glassy carbon structure was not achieved at the highest annealing temperature of 600 °C. Diffusion of Cd in glassy carbon was already taking place during implantation at 430 °C. This diffusion of Cd was accompanied by significant loss from the surface during implantation at 600 °C. Isochronal annealing of the room temperature implanted samples at 350 °C for 1 hour caused Cd to diffuse towards the bulk while isothermal annealing at 500 and 600 °C resulted in the migration of implanted Cd toward the surface accompanied by a loss of Cd from the surface. Isothermal annealing at 350 °C for 1 hour caused Cd to diffuse towards the bulk while for annealing time > 1 hour Cd diffused towards the surface. These results were interpreted in terms of trapping and de-trapping of implanted Cd by radiation damage.

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Section: Introductionmentioning

confidence: 99%

Annealing effects on the migration of ion-implanted cadmium in glassy carbon

Hlatshwayo

Sebitla

Njoroge

et al. 2017

Nuclear Instruments and Methods in Physics Research Section B:

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“…In the literature, coatings of carbonaceous materials have also been proposed in an attempt to avoid the in ltration of molten salts into the interior of graphite samples. Bernardet et al 11) coated glassy carbon and pyrolytic carbon on a graphite substrate and found that pyrolytic carbon was more effective than glassy carbon in the protection of a graphite substrate against a molten salt attack. The effectiveness of using pyrolytic carbon to seal graphite from molten salts was also reported in the studies of Feng et al 12) , He et al 19) and Song et al 20) The comparison in terms of sealing effectiveness against molten salts between pyrolytic carbon and the graphite foil used in the present study needs further assessment.…”

Section: Resultsmentioning

confidence: 99%

“…In MSR, molten salt ows between the reactor core and the heat exchanger serve as both fuel and coolant. Due to its chemical inertness, ability to slow down fast neutrons and good irradiation resistance, graphite has been proposed as a candidate for exposure to molten salts as a moderator channel [8][9][10][11][12][13] . Graphite is generally resistant to chemical attack by uoride salts 8,9) ; nevertheless, nuclear grade graphite generally demonstrates relatively low mechanical strength and a relatively high level of porosity 11,12) .…”

Section: The Corrosion Behavior Of a Variety Of Ceramics In Lif-mentioning

confidence: 99%

Graphite Foil-Incorporated PAN/Pitch/Phenolic-Derived Carbon/Carbon Composite and Preliminary Hermetic Sealing Test in Molten Fluoride Salt

et al. 2017

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“…GC has many useful industrial applications such as vacuum evaporation sources, containment of fission products (FPs), zone-refinement crucibles and encapsulation of nuclear fuel elements [8,9]. This material has been proposed as a protective layer on the graphite reactor core surface and as a candidate material for cooling pipes in molten salt reactor nuclear power plants [12]. Indium (In) is a heavy element which has a low melting point (156 °C), reasonably good electrical and thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

Structural modification of indium implanted glassy carbon by thermal annealing and SHI irradiation

Njoroge

Sebitla

Theron

et al. 2017

Vacuum

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The structural changes, migration behaviour of indium (In) implanted into glassy carbon (GC) and the effect of annealing on radiation damage introduced by ion implantation have been investigated. The GC substrates were implanted with 360 keV indium ions to a fluence of 2.0×10 16 ions/cm 2 at room temperature (RT) and 350 °C. The RT implanted samples were isochronally annealed in vacuum between 200 and 1000 °C for 1 hour. The 350 °C implanted GC substrates were irradiated 167 MeV with Xe 26+ ions at room temperature to a maximum fluence of 5.0×10 14 ions/cm 2. The implanted GC structure was damaged and had an almost amorphized structure. Annealing of the RT implanted samples resulted in some recrystallization which increased with temperature and the diffusion behaviour of implanted In. Fickian diffusion of implanted In started after annealing at 300 °C, however, structural changes in the GC were observed after annealing at 200 °C. Annealing at 400 and 600 °C resulted in the diffusion of In toward the surface of GC accompanied by a loss of In. The SHI irradiation of the 350 °C implanted samples at increasing fluence, did not result in a detectable migration of implanted In.

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Protection of nuclear graphite toward fluoride molten salt by glassy carbon deposit

Cited by 48 publications

References 20 publications

Annealing effects on the migration of ion-implanted cadmium in glassy carbon

Annealing effects on the migration of ion-implanted cadmium in glassy carbon

Graphite Foil-Incorporated PAN/Pitch/Phenolic-Derived Carbon/Carbon Composite and Preliminary Hermetic Sealing Test in Molten Fluoride Salt

Structural modification of indium implanted glassy carbon by thermal annealing and SHI irradiation

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