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Modelling the gas transport and chemical processes related to clad oxidation and hydriding

Abstract

Models are developed for the gas transport and chemical processes associated with the ingress of steam into a LWR fuel rod through a small defect. These models are used to determine the cladding regions in a defective fuel rod which are susceptible to massive hydriding and the creation of sunburst hydrides. The brittle nature of zirconium hydrides (ZrH{sub 2}) in these susceptible regions produces weak spots in the cladding which can act as initiation sites for cladding cracks under certain cladding stress conditions caused by fuel cladding mechanical interaction. The modeling of the axial gas transport is based on gaseous bimolar diffusion coupled with convective mass transport using the mass continuity equation. Hydrogen production is considered from steam reaction with cladding inner surface, fission products and internal components. Eventually, the production of hydrogen and its diffusion along the length results in high hydrogen concentration in locations remote from the primary defect. Under these conditions, the hydrogen can attack the cladding inner surface and breakdown the protective ZrO{sub 2} layer locally, initiating massive localized hydriding leading to sunburst hydride. The developed hydrogen evolution model is combined with a general purpose fuel behavior program to integrate the effects of power and burnup  More>>
Authors:
Montgomery, R O; Rashid, Y R [1] 
  1. ANATECH Research Corp., San Diego, CA (United States)
Publication Date:
Aug 01, 1997
Product Type:
Conference
Report Number:
IAEA-TECDOC-957; CONF-9409411-
Reference Number:
SCA: 210200; 210100; PA: AIX-28:068467; EDB-97:129967; SN: 97001863073
Resource Relation:
Conference: IAEA technical committee meeting on water reactor fuel element modelling at high burnup and its experimental support, Windermere (United Kingdom), 19-23 Sep 1994; Other Information: PBD: Aug 1997; Related Information: Is Part Of Water reactor fuel element modelling at high burnup and its experimental support. Proceedings of a technical committee meeting; PB: 559 p.
Subject:
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; CHEMICAL REACTIONS; SIMULATION; FUEL CANS; HYDRATION; OXIDATION; ATOM TRANSPORT; BWR TYPE REACTORS; GASES; PWR TYPE REACTORS
OSTI ID:
534362
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 1011-4289; Other: ON: DE98602336; TRN: XA9744810068467
Availability:
INIS; OSTI as DE98602336
Submitting Site:
INIS
Size:
pp. 347-360
Announcement Date:

Citation Formats

Montgomery, R O, and Rashid, Y R. Modelling the gas transport and chemical processes related to clad oxidation and hydriding. IAEA: N. p., 1997. Web.
Montgomery, R O, & Rashid, Y R. Modelling the gas transport and chemical processes related to clad oxidation and hydriding. IAEA.
Montgomery, R O, and Rashid, Y R. 1997. "Modelling the gas transport and chemical processes related to clad oxidation and hydriding." IAEA.
@misc{etde_534362,
title = {Modelling the gas transport and chemical processes related to clad oxidation and hydriding}
author = {Montgomery, R O, and Rashid, Y R}
abstractNote = {Models are developed for the gas transport and chemical processes associated with the ingress of steam into a LWR fuel rod through a small defect. These models are used to determine the cladding regions in a defective fuel rod which are susceptible to massive hydriding and the creation of sunburst hydrides. The brittle nature of zirconium hydrides (ZrH{sub 2}) in these susceptible regions produces weak spots in the cladding which can act as initiation sites for cladding cracks under certain cladding stress conditions caused by fuel cladding mechanical interaction. The modeling of the axial gas transport is based on gaseous bimolar diffusion coupled with convective mass transport using the mass continuity equation. Hydrogen production is considered from steam reaction with cladding inner surface, fission products and internal components. Eventually, the production of hydrogen and its diffusion along the length results in high hydrogen concentration in locations remote from the primary defect. Under these conditions, the hydrogen can attack the cladding inner surface and breakdown the protective ZrO{sub 2} layer locally, initiating massive localized hydriding leading to sunburst hydride. The developed hydrogen evolution model is combined with a general purpose fuel behavior program to integrate the effects of power and burnup into the hydriding kinetics. Only in this manner can the behavior of a defected fuel rod be modeled to determine the conditions the result in fuel rod degradation. (author). 14 refs, 6 figs.}
place = {IAEA}
year = {1997}
month = {Aug}
}