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Title: Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure

Abstract

Tungsten brush accommodates thermal stresses and high heat flux in fusion reactor components such as plasma facing surfaces or armor. However, inherently higher surface areas are introduced with the brush design. We have tested a specific design of tungsten brush in steam between 500 and 1100°C. Hydrogen generation and tungsten volatilization rates were determined to address fusion safety issues. The brush prepared from 3.2-mm diameter welding rods had a packing density of 85 percent. We found that both hydrogen generation and tungsten volatilization from brush, fixtured to represent a unit within a larger component, were less than projections based upon the total integrated surface area (TSA). Steam access and the escape of hydrogen and volatile oxide from void spaces within the brush are restricted compared to specimens with more direct diffusion pathways to the test environment. Hydrogen generation rates from restrained specimens based on normal surface area (NSA) remain about five times higher than rates based on total surface areas from specimens with direct steam access. Volatilization rates from restrained specimens based upon normal surface area (NSA) were only 50 percent higher than our historic cumulative maximum flux plot (CMFP) for tungsten. This study has shown that hydrogen generation andmore » tungsten volatilization from brush do not scale according to predictions with previously determined rates, but in fact, with higher packing density could approach those from flat surfaces.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
USDOE
OSTI Identifier:
911474
Report Number(s):
INEEL/EXT-00-00390
DOE Contract Number:  
DE-AC07-99ID-13727
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
70 - PLASMA PHYSICS AND FUSION TECHNOLOGY; armor; diffusion pathways; fusion reactor; high heat flux; hydrogen generation; packing density; plasma facing surfaces; safety issues; steam access; thermal stresses; tungsten brush; tungsten volatilization

Citation Formats

Smolik, Galen Richard, Pawelko, Robert James, Anderl, Robert Andrew, and Petti, David Andrew. Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure. United States: N. p., 2000. Web. doi:10.2172/911474.
Smolik, Galen Richard, Pawelko, Robert James, Anderl, Robert Andrew, & Petti, David Andrew. Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure. United States. doi:10.2172/911474.
Smolik, Galen Richard, Pawelko, Robert James, Anderl, Robert Andrew, and Petti, David Andrew. Mon . "Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure". United States. doi:10.2172/911474. https://www.osti.gov/servlets/purl/911474.
@article{osti_911474,
title = {Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure},
author = {Smolik, Galen Richard and Pawelko, Robert James and Anderl, Robert Andrew and Petti, David Andrew},
abstractNote = {Tungsten brush accommodates thermal stresses and high heat flux in fusion reactor components such as plasma facing surfaces or armor. However, inherently higher surface areas are introduced with the brush design. We have tested a specific design of tungsten brush in steam between 500 and 1100°C. Hydrogen generation and tungsten volatilization rates were determined to address fusion safety issues. The brush prepared from 3.2-mm diameter welding rods had a packing density of 85 percent. We found that both hydrogen generation and tungsten volatilization from brush, fixtured to represent a unit within a larger component, were less than projections based upon the total integrated surface area (TSA). Steam access and the escape of hydrogen and volatile oxide from void spaces within the brush are restricted compared to specimens with more direct diffusion pathways to the test environment. Hydrogen generation rates from restrained specimens based on normal surface area (NSA) remain about five times higher than rates based on total surface areas from specimens with direct steam access. Volatilization rates from restrained specimens based upon normal surface area (NSA) were only 50 percent higher than our historic cumulative maximum flux plot (CMFP) for tungsten. This study has shown that hydrogen generation and tungsten volatilization from brush do not scale according to predictions with previously determined rates, but in fact, with higher packing density could approach those from flat surfaces.},
doi = {10.2172/911474},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {5}
}

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