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Title: Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report

Abstract

Preliminary designs are described for models of hydrogen and oxygen uptake in fuel rod cladding during severe accidents. Calculation of the uptake involves the modeling of seven processes: (1) diffusion of oxygen from the bulk gas into the boundary layer at the external cladding surface, (2) diffusion from the boundary layer into the oxide layer, (3) diffusion from the inner surface of the oxide layer into the metallic part of the cladding, (4) uptake of hydrogen in the event that the cladding oxide layer is dissolved in a steam-starved region, (5) embrittlement of cladding due to hydrogen uptake, (6) cracking of cladding during quenching due to its embrittlement and (7) release of hydrogen from the cladding after cracking of the cladding. An integral diffusion method is described for calculating the diffusion processes in the cladding. Experimental results are presented that show a rapid uptake of hydrogen in the event of dissolution of the oxide layer and a rapid release of hydrogen in the event of cracking of the oxide layer. These experimental results are used as a basis for calculating the rate of hydrogen uptake and the rate of hydrogen release. The uptake of hydrogen is limited to the equilibriummore » solubility calculated by applying Sievert's law. The uptake of hydrogen is an exothermic reaction that accelerates the heatup of a fuel rod. An embrittlement criteria is described that accounts for hydrogen and oxygen concentration and the extent of oxidation. A design is described for implementing the models for hydrogen and oxygen uptake and cladding embrittlement into the programming framework of the SCDAP/RELAP5 code. A test matrix is described for assessing the impact of the proposed models on the calculated behavior of fuel rods in severe accident conditions. This report is a revision and reissue of the report entitled; ``Preliminary Design Report for Modeling of Hydrogen Uptake in Fuel Rod Cladding During Severe Accidents.''« less

Authors:
Publication Date:
Research Org.:
Idaho National Engineering and Environmental Lab., Idaho Falls, ID (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
751980
Report Number(s):
INEEL/EXT-98-00664(Rev.1)
TRN: US0000905
DOE Contract Number:  
AC07-94ID13223
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Feb 1999
Country of Publication:
United States
Language:
English
Subject:
22 NUCLEAR REACTOR TECHNOLOGY; REACTOR ACCIDENTS; FUEL CANS; MATHEMATICAL MODELS; HYDROGEN; ABSORPTION; DIFFUSION; HYDROGEN EMBRITTLEMENT; OXYGEN; CRACK PROPAGATION; DESORPTION; OXIDATION; S CODES; R CODES; CLADDING EMBRITTLEMENT; OXYGEN DIFFUSION; HYDROGEN UPTAKE; OXYGEN UPTAKE; FUEL ROD CLADDING; SEVERE ACCIDENTS; BOUNDARY LAYER; OXIDE LAYER; QUENCHING; INTEGRAL DIFFUSION METHOD; HYDROGEN RELEASE; EQUILIBRIUM SOLUBILITY; SIEVERT'S LAW; SCDAP/RELAP5

Citation Formats

Siefken, L.J. Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report. United States: N. p., 1999. Web. doi:10.2172/751980.
Siefken, L.J. Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report. United States. doi:10.2172/751980.
Siefken, L.J. Mon . "Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report". United States. doi:10.2172/751980. https://www.osti.gov/servlets/purl/751980.
@article{osti_751980,
title = {Calculation of hydrogen and oxygen uptake in fuel rod cladding during severe accidents using the integral diffusion method -- Preliminary design report},
author = {Siefken, L.J.},
abstractNote = {Preliminary designs are described for models of hydrogen and oxygen uptake in fuel rod cladding during severe accidents. Calculation of the uptake involves the modeling of seven processes: (1) diffusion of oxygen from the bulk gas into the boundary layer at the external cladding surface, (2) diffusion from the boundary layer into the oxide layer, (3) diffusion from the inner surface of the oxide layer into the metallic part of the cladding, (4) uptake of hydrogen in the event that the cladding oxide layer is dissolved in a steam-starved region, (5) embrittlement of cladding due to hydrogen uptake, (6) cracking of cladding during quenching due to its embrittlement and (7) release of hydrogen from the cladding after cracking of the cladding. An integral diffusion method is described for calculating the diffusion processes in the cladding. Experimental results are presented that show a rapid uptake of hydrogen in the event of dissolution of the oxide layer and a rapid release of hydrogen in the event of cracking of the oxide layer. These experimental results are used as a basis for calculating the rate of hydrogen uptake and the rate of hydrogen release. The uptake of hydrogen is limited to the equilibrium solubility calculated by applying Sievert's law. The uptake of hydrogen is an exothermic reaction that accelerates the heatup of a fuel rod. An embrittlement criteria is described that accounts for hydrogen and oxygen concentration and the extent of oxidation. A design is described for implementing the models for hydrogen and oxygen uptake and cladding embrittlement into the programming framework of the SCDAP/RELAP5 code. A test matrix is described for assessing the impact of the proposed models on the calculated behavior of fuel rods in severe accident conditions. This report is a revision and reissue of the report entitled; ``Preliminary Design Report for Modeling of Hydrogen Uptake in Fuel Rod Cladding During Severe Accidents.''},
doi = {10.2172/751980},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1999},
month = {2}
}