Pulse high heat flux experiment with laser beams on graphite

Kamezaki, H.; Tokunaga, Kazutoshi; Fukuda, Sho; Yoshida, N.; Muroga, T.

doi:10.1016/0022-3115(91)90059-g

Cited by 8 publications

(3 citation statements)

References 10 publications

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“…Evidence suggests that single-crystal (i.e., well ordered) graphite targets produce larger clusters than do amorphous carbon targets. 49,58 With laser irradiation in the visible and IR, small clusters consisting of a few carbon atoms are produced, 44,55,56,[59][60][61][62][63][64][65][66][67][68][69][70][71][72] but larger clusters (with as many as 100 carbon atoms) are also commonly observed in these wavelength regions under vacuum. 46,56,61,62,73 At these wavelengths large clusters, fullerenes, and nanoparticles can be formed at higher pressures 53,54,64,[74][75][76][77][78] or when expanded in a buffer gas into a vacuum.…”

Section: Previous Resultsmentioning

confidence: 99%

Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope

Michelsen¹,

Tivanski²,

Gilles³

et al. 2007

Appl. Opt.

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*Send correspondence to hamiche@ca.sandia.gov A scanning mobility particle sizer was used to measure changes in size distributions of soot particles when exposed to laser radiation at 532 or 1064 nm with fluences up to 0.8 J/cm 2 . Laser-induced production of carbon nanoparticles was observed at fluences above 0.12 J/cm 2 at 532 nm and 0.22 J/cm 2 at 1064 nm. Near-edge x-ray absorption fine structure spectra showed predominantly graphitic (sp 2 -hybridized) carbon in the non-irradiated particles and significantly different features in the irradiated particles. These results are consistent with differences in the fine structure between irradiated and non-irradiated samples observed by transmission electron microscopy.Copyright 2

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Section: Previous Resultsmentioning

confidence: 99%

Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope

Michelsen¹,

Tivanski²,

Gilles³

et al. 2007

Appl. Opt.

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“…Numerous experimental investigations related to laser produced carbon plasma formed by solid targets have been reported [20][21][22][23]. Interaction of carbon plasma with a wide range of ambient gas environments [14,15,[24][25][26] and with different laser irradiance [19,27] has also been reported in the last few years.…”

Section: Introductionmentioning

confidence: 99%

Effects of ambient pressure and laser fluence on the temporal evolution of 426.7 nm CII line in laser-blow-off of multilayered LiF-C thin film

Kumar¹,

Singh²,

Subramanian³

et al. 2006

J. Phys. D: Appl. Phys.

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The time and space resolved emission profiles of the CII line from the laser-blow-off (LBO) plumes of multilayered LiF-C thin film have been investigated using a laser-induced forward transfer technique. The evolution features of the 426.7 nm line were studied in different ambient environments ranging from high vacuum to 3 mbar of argon pressures and at various fluences of the ablating laser. It was found that many features of the plasma plume generated by the LBO method resemble that of plumes created in conventional laser produced plasma; however, a few differences were observed in their behaviour with regard to plume splitting and plume compression. A sudden change in the temporal profile was observed to occur at a distance about 4–6 mm away from the target. The variation of the plume structures observed at different fluences of the ablating laser is reported. The validity of the Rayleigh–Taylor instability, shock wave and drag force model in the present experiment are also discussed.

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“…Heat flux experiments on A-3 graphite were conducted and reported in 1991 with a ruby laser with output of 6.4 J and a pulse length of 1 ms. These conditions were able to deliver calculated heat loads up to 4,200 MW/m 2 , increasing temperature to >3,000 °C, which cooled to 600 °C after 3 ms. (H. Kamezaki, 1991) This work was investigating gas release and sublimation under vacuum and did not give mass change data. The long pulse length would not likely cause a shockwave for fragmentation, and no mention of such was given in article.…”

Section: Potential Methodsmentioning

confidence: 99%

High temperature gas-cooled reactor (HTGR) graphite pebble fuel: Review of technologies for reprocessing

McWilliams

2015

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This report reviews literature on reprocessing high temperature gas-cooled reactor graphite fuel components. A basic review of the various fuel components used in the pebble bed type reactors is provided along with a survey of synthesis methods for the fabrication of the fuel components. Several disposal options are considered for the graphite pebble fuel elements including the storage of intact pebbles, volume reduction by separating the graphite from fuel kernels, and complete processing of the pebbles for waste storage. Existing methods for graphite removal are presented and generally consist of mechanical separation techniques such as crushing and grinding and chemical techniques through the use of acid digestion and oxidation. Potential methods for reprocessing the graphite pebbles include improvements to existing methods and novel technologies that have not previously been investigated for nuclear graphite waste applications. The best overall method will be dependent on the desired final waste form and needs to factor in the technical efficiency, political concerns, cost, and implementation.

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Pulse high heat flux experiment with laser beams on graphite

Cited by 8 publications

References 10 publications

Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope

Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope

Effects of ambient pressure and laser fluence on the temporal evolution of 426.7 nm CII line in laser-blow-off of multilayered LiF-C thin film

High temperature gas-cooled reactor (HTGR) graphite pebble fuel: Review of technologies for reprocessing

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