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Title: Analysis of Double-encapsulated Fuel Rods

Abstract

In an LWR fuel rod, the cladding encapsulates the fuel, contains fission products, and transfers heat directly to the water coolant. In some situations, it may be advantageous to separate the cladding from the coolant through use of a secondary cladding or capsule. This may be done to increase confidence that the fuel or fission products will not mix with the coolant, to provide a mechanism for controlling the rod temperature, or to place multiple experimental rodlets within a single housing. With an axisymmetric assumption, it is possible to derive closed-form expressions for the temperature profile in a fuel rod using radially-constant thermal conductivity in the fuel. This is true for both a traditional fuel-cladding rod and a double-encapsulated fuel (fuel, cladding, capsule) configuration. Likewise, it is possible to employ a fuel performance code to analyse both a traditional and a double-encapsulated fuel. In the case of the latter, two sets of gap heat transfer conditions must be imposed. In this work, we review the equations associated with radial heat transfer in a cylindrical system, present analytic and computational results for a postulated power and gas mixture history for IFA-744, and describe the analysis of the AFC-2A, 2B metallic fuelmore » alloy experiments at the Advanced Test Reactor, including the effect of a release of fission products into the cladding-capsule gap. The computational results for these two cases were obtained using BISON, a fuel performance code under development at Idaho National Laboratory.« less

Authors:
 [1];  [1];  [1];  [1];  [1]
  1. Idaho National Laboratory
Publication Date:
Research Org.:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1236814
Report Number(s):
INL/CON-14-32155
DOE Contract Number:
AC07-05ID14517
Resource Type:
Conference
Resource Relation:
Conference: Enlarged Halden Programme Group Meeting 2014, Roros, Norway, 9/7/2014 - 9/12/2014
Country of Publication:
United States
Language:
English
Subject:
BISON; nuclear fuel performance

Citation Formats

Hales, Jason Dean, Medvedev, Pavel G, Novascone, Stephen Rhead, Perez, Danielle Marie, and Williamson, Richard L. Analysis of Double-encapsulated Fuel Rods. United States: N. p., 2014. Web.
Hales, Jason Dean, Medvedev, Pavel G, Novascone, Stephen Rhead, Perez, Danielle Marie, & Williamson, Richard L. Analysis of Double-encapsulated Fuel Rods. United States.
Hales, Jason Dean, Medvedev, Pavel G, Novascone, Stephen Rhead, Perez, Danielle Marie, and Williamson, Richard L. Mon . "Analysis of Double-encapsulated Fuel Rods". United States. doi:. https://www.osti.gov/servlets/purl/1236814.
@article{osti_1236814,
title = {Analysis of Double-encapsulated Fuel Rods},
author = {Hales, Jason Dean and Medvedev, Pavel G and Novascone, Stephen Rhead and Perez, Danielle Marie and Williamson, Richard L},
abstractNote = {In an LWR fuel rod, the cladding encapsulates the fuel, contains fission products, and transfers heat directly to the water coolant. In some situations, it may be advantageous to separate the cladding from the coolant through use of a secondary cladding or capsule. This may be done to increase confidence that the fuel or fission products will not mix with the coolant, to provide a mechanism for controlling the rod temperature, or to place multiple experimental rodlets within a single housing. With an axisymmetric assumption, it is possible to derive closed-form expressions for the temperature profile in a fuel rod using radially-constant thermal conductivity in the fuel. This is true for both a traditional fuel-cladding rod and a double-encapsulated fuel (fuel, cladding, capsule) configuration. Likewise, it is possible to employ a fuel performance code to analyse both a traditional and a double-encapsulated fuel. In the case of the latter, two sets of gap heat transfer conditions must be imposed. In this work, we review the equations associated with radial heat transfer in a cylindrical system, present analytic and computational results for a postulated power and gas mixture history for IFA-744, and describe the analysis of the AFC-2A, 2B metallic fuel alloy experiments at the Advanced Test Reactor, including the effect of a release of fission products into the cladding-capsule gap. The computational results for these two cases were obtained using BISON, a fuel performance code under development at Idaho National Laboratory.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}

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  • An equilibrium core for supercritical light water reactor has been designed. A novel type of fuel assembly with dual rows of fuel rods between water rods is chosen and optimized to get more uniform assembly power distributions. Stainless steel is used for fuel rod cladding and structural material. Honeycomb structure filled with thermal isolation is introduced to reduce the usage of stainless steel and to keep moderator temperature below the pseudo critical temperature. Water flow scheme with ascending coolant flow in inner regions is carried out to achieve high outlet temperature. In order to enhance coolant outlet temperature, the radialmore » power distributions needs to be as flat as possible through operation cycle. Fuel loading pattern and control rod pattern are optimized to flatten power distribution at inner regions. Axial fuel enrichment is divided into three parts to control axial power peak, which affects maximum cladding surface temperature. (authors)« less
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