A study of reactivity biases and their dependence on spatial discretization in depleted TRIGA fuel
Abstract
The impact of spatial discretization on reactivity biases in TRIGA fuel models was analyzed here. In particular, unit-cell analyses in 2-D and 3-D were performed using Serpent to understand how spatial discretization affects the accuracy with which the effects of material evolution and temperature feedback are resolved. For temperature-dependent cases, a simple, single-channel model was employed. Analysis of 2-D models showed that essentially no radial discretization resolution is needed to eliminate biases (i.e., to reduce biases to the level of stochastic uncertainties) due to material evolution but that more than eight, equal-area, radial regions are needed to resolve temperature-feedback effects. Analysis of 3-D models showed that at least seven, equal-volume, axial regions may be required to resolve material evolution with temperature feedback leading to insignificant additional bias. Because of memory constraints, a full-core model with radially- and axially-resolved fuel elements may be impractical, especially for production-level analyses. Consequently, an “effective Doppler temperature” was determined empirically as a function of the radially-averaged temperature and may be used for future, full-core analyses.
- Authors:
-
- Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical and Nuclear Engineering
- Publication Date:
- Research Org.:
- Kansas State Univ., Manhattan, KS (United States)
- Sponsoring Org.:
- USDOE Office of Nuclear Energy (NE); Nuclear Regulatory Commission (NRC) (United States)
- OSTI Identifier:
- 1494564
- Alternate Identifier(s):
- OSTI ID: 1416029
- Grant/Contract Number:
- NE0008408; NRC-HQ-60-15-G-0004
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Annals of Nuclear Energy (Oxford)
- Additional Journal Information:
- Journal Name: Annals of Nuclear Energy (Oxford); Journal Volume: 108; Journal ID: ISSN 0306-4549
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; reactivity bias; TRIGA; fuel depletion; temperature feedback; effective temperature
Citation Formats
Cheng, Ye, and Roberts, Jeremy A. A study of reactivity biases and their dependence on spatial discretization in depleted TRIGA fuel. United States: N. p., 2017.
Web. doi:10.1016/j.anucene.2017.04.030.
Cheng, Ye, & Roberts, Jeremy A. A study of reactivity biases and their dependence on spatial discretization in depleted TRIGA fuel. United States. https://doi.org/10.1016/j.anucene.2017.04.030
Cheng, Ye, and Roberts, Jeremy A. Thu .
"A study of reactivity biases and their dependence on spatial discretization in depleted TRIGA fuel". United States. https://doi.org/10.1016/j.anucene.2017.04.030. https://www.osti.gov/servlets/purl/1494564.
@article{osti_1494564,
title = {A study of reactivity biases and their dependence on spatial discretization in depleted TRIGA fuel},
author = {Cheng, Ye and Roberts, Jeremy A.},
abstractNote = {The impact of spatial discretization on reactivity biases in TRIGA fuel models was analyzed here. In particular, unit-cell analyses in 2-D and 3-D were performed using Serpent to understand how spatial discretization affects the accuracy with which the effects of material evolution and temperature feedback are resolved. For temperature-dependent cases, a simple, single-channel model was employed. Analysis of 2-D models showed that essentially no radial discretization resolution is needed to eliminate biases (i.e., to reduce biases to the level of stochastic uncertainties) due to material evolution but that more than eight, equal-area, radial regions are needed to resolve temperature-feedback effects. Analysis of 3-D models showed that at least seven, equal-volume, axial regions may be required to resolve material evolution with temperature feedback leading to insignificant additional bias. Because of memory constraints, a full-core model with radially- and axially-resolved fuel elements may be impractical, especially for production-level analyses. Consequently, an “effective Doppler temperature” was determined empirically as a function of the radially-averaged temperature and may be used for future, full-core analyses.},
doi = {10.1016/j.anucene.2017.04.030},
journal = {Annals of Nuclear Energy (Oxford)},
number = ,
volume = 108,
place = {United States},
year = {Thu May 04 00:00:00 EDT 2017},
month = {Thu May 04 00:00:00 EDT 2017}
}
Web of Science
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