BET surface area measurements of materials for fusion safety studies

Smolik, G.R.; Anderl, R.A.; Pawelko, R.J.; Carmack, Jon; Hembree, P.B.; Oates, M.A.

doi:10.1109/fusion.1997.687016

Cited by 7 publications

(7 citation statements)

References 8 publications

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“…This type of plot, referred to as an adsorption isotherm, is used to calculate the specific surface area of the sample material. This method was developed by Brunauer, Emmett, and Teller, (BET) 2 and a complete description of our capabilities and methods is available in Anderl et al 3 and Smolik et al 4 For our measurements, both Kr and N 2 were used as the adsorptive gas in separate measurements and the adsorption measurements were made with the specimens at liquid nitrogen temperature (77 K). Generally, Kr gas is used when samples are expected to have very low total surface areas.…”

Section: Bet Surface Area Analysismentioning

confidence: 99%

DIII-D Dust Particulate Characterization (June 1998 Vent)

Carmack¹

1999

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SUMMARYDust is a key component of fusion power device accident source term. Understanding the amount of dust expected in fusion power devices and its physical and chemical characteristics is needed to verify assumptions currently used in safety analyses. An important part of this safety research and development work is to characterize dust from existing experimental tokamaks. In this report, we present the collection, data analysis methods used, and the characterization of dust particulate collected from various locations inside the General Atomics DIII-D vacuum vessel following the June 1998 vent. DIII-D is located in San Diego, California. The collected particulate was analyzed at the Idaho National Engineering and Environmental Laboratory (INEEL).Two methods were used to collect particulate with the goal of preserving the particle size distribution and physical characteristics of the particulate. Choice of collection technique is important because the sampling method used can bias the particle size distribution collected. Vacuum collection on substrates and adhesion removal with metallurgical replicating tape were chosen as non-intrusive sampling methods. Sampling was completed in four areas of the machine; 0 to 90° area, the 90° to 180° area, the 180° to 270° area, and the 270° to 360° area. The 0° direction designates the north side of the DIII-D machine. Seventeen samples were collected including plasma facing surfaces in lower, upper, and horizontal locations, surfaces behind floor tiles, surfaces behind divertor tiles, and surfaces behind ceiling tiles. The results of the analysis are listed below.• Our Brunauer, Emmett, and Teller (BET) specific surface area analysis results are based upon three measurements of a sample combined from approximately 75% of the filter housing samples. The samples were combined to yield a detectable surface area of dust. The combined sample had an average specific surface area of 3.18 m 2 /gram from a total sample weight of 0.11 grams. This value is very similar to the value obtained in the 1996 DIII-D dust campaign and is a factor of 2 greater than that for theoretically dense graphite spheres. This indicates that as previously observed, the particulate is not spherical and is composed of agglomerates of smaller particles.• The particle size distribution analysis results of dust taken from inside the vacuum vessel show a range of count median diameter (CMD) values ranging between 0.81 µm and 2.89 µm with a range of geometric standard deviation (GSD) values between 1.33 and 3.43. D MVS values ranged between 1.1 and 13.3 µm. The mass median diameter (MMD) of the particulate was determined from the cascade impactor data. The MMD's were 7.25 µm with a GSD of 1.4 and 5.44 µm with a GSD of 2.2. The observed particles appeared in the form of both flakes and spheres. Compositional analysis by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) showed individual dust composed of molybdenum, iron, boron, and aluminum. Overall chemical analysis by inductively couple...

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Section: Bet Surface Area Analysismentioning

confidence: 99%

DIII-D Dust Particulate Characterization (June 1998 Vent)

Carmack¹

1999

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“…Such microcracking would provide gas access to the porosity network in each material resulting in gas adsorption on nearly equivalent internal surface areas. These measurements indicate that the NS31 and NB31 materials have specific surface areas that are less than those measured [7] for some bulk graphites ( 0.75 m 2 /g for H451, 0.69 m 2 /g for GRAPHNOL N3M, 0.34 m 2 /g for POCO AXF-5Q) but greater than that measured for pyrolytic graphite (0.04 m 2 /g).…”

Section: Discussionmentioning

confidence: 56%

“…Extensive details of this measurement approach and application to other fusion-relevant materials are reported elsewhere [7,8]. However, for completeness, a description of the measurement and analysis approach is given here.…”

Section: Bet Specific Surface Areamentioning

confidence: 99%

Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

Anderl¹,

Pawelko²,

Smolik³

2001

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“…The specific experimental procedures described here were initially established and optimized by Smolik et al [6]. For this study, the BET surface area measurements were obtained with a Micromeritics ASAP 2000 instrument with Kr gas serving as the adsorptive.…”

Section: Specific Surface Area Analysismentioning

confidence: 99%

The impact of specific surface area on the retention of deuterium in carbon fiber composite materials

Kolasinski

Umstadter

Sharpe

et al. 2009

Fusion Engineering and Design

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a b s t r a c tIn this study, the PISCES-A linear plasma instrument has been used to characterize retention in several carbon fiber composites in order to better understand the factors which lead to elevated retention levels in these materials. The PISCES instrument is capable of subjecting materials to intense fluxes (up to 10 22 m −2 s −1 ) of low energy (150 eV) D + ions, producing conditions similar to those encountered by plasma facing components in a fusion reactor. In this investigation, three CFCs (fabricated with different manufacturing processes) are compared with the N11 composite used in the Tore Supra reactor. The specific surface areas for these materials were within the range of 0.14-0.55 m 2 /g. The plasma bombardment conditions were adjusted to provide doses on the order of 10 25 -10 26 m −2 at a sample temperature of 200 • C. After removal from PISCES-A, the amount of D retained in the sample surface was determined via thermal desorption spectroscopy. The measured retention showed a strong correlation with the type of material used and the corresponding BET surface area. By using a CFC with a lower internal porosity, one could expect a reduction in retention by a factor of 5 or more.

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BET surface area measurements of materials for fusion safety studies

Cited by 7 publications

References 8 publications

DIII-D Dust Particulate Characterization (June 1998 Vent)

DIII-D Dust Particulate Characterization (June 1998 Vent)

Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

The impact of specific surface area on the retention of deuterium in carbon fiber composite materials

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