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Plasma cooling by metal snow. I. Origin of the effect and elimination procedures

Abstract

In many plasma devices, steel or inconel walls are exposed to large flux densities phi/sub 1/ of atomic hydrogen particles which, soon after the reduction of the surface oxides and carbides has started, penetrate into the lattice. The stationary hydrogen concentration c/sub 1/ in the lattice is expressed as function of phi/sub 1/, of the wall temperature Tsub(w) and of the surface roughness factor sigma. It is found to be much larger than in an H/sub 2/ surrounding. Dissolved atoms recombining on internal surfaces (i.e. at grain boundaries) within the solid can then build up a considerable pressure Psup(p)sub(H/sub 2/) within resulting gas pockets; Psup(p)sub(H/sub 2/) should depend strongly on Tsub(w). Near room temperature, the computed values are such that surface-near pockets should crack open, releasing locally high pressure H/sub 2/ gas and some metal dust (impurity source) and increasing sigma. The expected distribution of csub(H) within the sponge-like structure which is expected to result from a prolonged exposure to phi/sub 1/ at low Tsub(w) is derived. Means of avoiding the plasma contamination by dust release are pointed out.
Authors:
Khan, I A; Dietz, K J; Waelbroeck, F; Wienhold, P [1] 
  1. Kernforschungsanlage Juelich G.m.b.H. (Germany, F.R.). Inst. fuer Plasmaphysik
Publication Date:
Jun 01, 1978
Product Type:
Journal Article
Reference Number:
AIX-10-419656; EDB-79-063665
Resource Relation:
Journal Name: J. Nucl. Mater.; (Netherlands); Journal Volume: 74:1
Subject:
36 MATERIALS SCIENCE; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; INCONEL ALLOYS; PHYSICAL RADIATION EFFECTS; STEELS; TOKAMAK DEVICES; BUBBLES; CONFINEMENT; CONTINUITY EQUATIONS; CRACKS; CRYSTAL LATTICES; DIFFUSION; DISLOCATIONS; DUSTS; FLUX DENSITY; GRAIN BOUNDARIES; HIGH TEMPERATURE; HYDROGEN; HYDROGEN IONS 1 PLUS; HYPOTHESIS; IMPURITIES; LOW TEMPERATURE; MEDIUM TEMPERATURE; PLASMA; RADIATION FLUX; RECOMBINATION; ROUGHNESS; SOLUBILITY; SURFACES; TEMPERATURE DEPENDENCE; ALLOYS; CATIONS; CHARGED PARTICLES; CHROMIUM ALLOYS; CLOSED PLASMA DEVICES; CRYOGENIC FLUIDS; CRYSTAL DEFECTS; CRYSTAL STRUCTURE; DIFFERENTIAL EQUATIONS; ELEMENTS; EQUATIONS; FLUIDS; HYDROGEN IONS; IONS; IRON ALLOYS; IRON BASE ALLOYS; LINE DEFECTS; MICROSTRUCTURE; NICKEL ALLOYS; NICKEL BASE ALLOYS; NONMETALS; RADIATION EFFECTS; SURFACE PROPERTIES; THERMONUCLEAR DEVICES; 360106* - Metals & Alloys- Radiation Effects; 700209 - Fusion Power Plant Technology- Component Development & Materials Testing
OSTI ID:
6380187
Country of Origin:
Netherlands
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: JNUMA
Submitting Site:
INIS
Size:
Pages: 132-137
Announcement Date:
Feb 01, 1979

Citation Formats

Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P. Plasma cooling by metal snow. I. Origin of the effect and elimination procedures. Netherlands: N. p., 1978. Web. doi:10.1016/0022-3115(78)90541-X.
Khan, I A, Dietz, K J, Waelbroeck, F, & Wienhold, P. Plasma cooling by metal snow. I. Origin of the effect and elimination procedures. Netherlands. https://doi.org/10.1016/0022-3115(78)90541-X
Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P. 1978. "Plasma cooling by metal snow. I. Origin of the effect and elimination procedures." Netherlands. https://doi.org/10.1016/0022-3115(78)90541-X.
@misc{etde_6380187,
title = {Plasma cooling by metal snow. I. Origin of the effect and elimination procedures}
author = {Khan, I A, Dietz, K J, Waelbroeck, F, and Wienhold, P}
abstractNote = {In many plasma devices, steel or inconel walls are exposed to large flux densities phi/sub 1/ of atomic hydrogen particles which, soon after the reduction of the surface oxides and carbides has started, penetrate into the lattice. The stationary hydrogen concentration c/sub 1/ in the lattice is expressed as function of phi/sub 1/, of the wall temperature Tsub(w) and of the surface roughness factor sigma. It is found to be much larger than in an H/sub 2/ surrounding. Dissolved atoms recombining on internal surfaces (i.e. at grain boundaries) within the solid can then build up a considerable pressure Psup(p)sub(H/sub 2/) within resulting gas pockets; Psup(p)sub(H/sub 2/) should depend strongly on Tsub(w). Near room temperature, the computed values are such that surface-near pockets should crack open, releasing locally high pressure H/sub 2/ gas and some metal dust (impurity source) and increasing sigma. The expected distribution of csub(H) within the sponge-like structure which is expected to result from a prolonged exposure to phi/sub 1/ at low Tsub(w) is derived. Means of avoiding the plasma contamination by dust release are pointed out.}
doi = {10.1016/0022-3115(78)90541-X}
journal = []
volume = {74:1}
journal type = {AC}
place = {Netherlands}
year = {1978}
month = {Jun}
}