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Title: SLOWPOKE-2 alternative core loading configurations analysis for highly improved reactor performance

Abstract

Here, a thorough analysis was carried out and is presented here exploring the possibilities for performance improvement of the LEU-fueled SLOWPOKE-2 reactor design, mainly with regard to the fuel pins distribution throughout the core. The chosen performance metric to maximize was the thermal neutron flux at the inner irradiation sites, while the essential constrain was to maintain the same Onset of Nucleate Boiling Ratio (ONBR) at nominal power, established as general safety criterion. MCNP5 and PLTEMP/ANL codes were used for the neutronics and thermal hydraulics simulations respectively, to analyze the reactor behavior under nearly 300 different core configurations or fuel loading patterns. The main proposed configuration, involving 270 fuel pins and minor modifications to the fuel cage, is predicted to allow a performance improvement of about 72.5% while maintaining the same safety margins. Additional or alternative, more complex modifications of the reactor for even further performance increases, involving changes to the fuel, the annular reflector and the control rod, are also suggested and analyzed in some detail. The basis to reduce or recover safety margin to reach higher power and flux levels, with the potential to at least double current performance when combined with suggested modifications, is also briefly examined.more » Possible effects of the higher reactor power on the reactor operation are considered as well, providing additional potential modifications to extend the maximum continuous operation time and the period between Be shims adjustments. Overall, this work constitutes a solid and detailed reference basis for very substantial potential performance improvements for SLOWPOKE-2 reactors that are pending conversion to LEU and those that may need refueling in the future. It also points out possible, though foreseeable more limited, performance improvements on MNSR reactors.« less

Authors:
ORCiD logo [1];  [2]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
  2. Univ. of the West Indies, Kingston (Jamaica)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20); USDOE National Nuclear Security Administration (NNSA), Office of Material Management and Minimization (NA-23) Reactor Conversion Program
OSTI Identifier:
1547859
Alternate Identifier(s):
OSTI ID: 1491836
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Published Article
Journal Name:
Annals of Nuclear Energy (Oxford)
Additional Journal Information:
Journal Name: Annals of Nuclear Energy (Oxford); Journal Volume: 128; Journal Issue: C; Journal ID: ISSN 0306-4549
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; core; SLOWPOKE; neutron flux; optimization

Citation Formats

Puig, Francesc, and Dennis, Haile. SLOWPOKE-2 alternative core loading configurations analysis for highly improved reactor performance. United States: N. p., 2019. Web. doi:10.1016/j.anucene.2018.12.016.
Puig, Francesc, & Dennis, Haile. SLOWPOKE-2 alternative core loading configurations analysis for highly improved reactor performance. United States. doi:10.1016/j.anucene.2018.12.016.
Puig, Francesc, and Dennis, Haile. Wed . "SLOWPOKE-2 alternative core loading configurations analysis for highly improved reactor performance". United States. doi:10.1016/j.anucene.2018.12.016.
@article{osti_1547859,
title = {SLOWPOKE-2 alternative core loading configurations analysis for highly improved reactor performance},
author = {Puig, Francesc and Dennis, Haile},
abstractNote = {Here, a thorough analysis was carried out and is presented here exploring the possibilities for performance improvement of the LEU-fueled SLOWPOKE-2 reactor design, mainly with regard to the fuel pins distribution throughout the core. The chosen performance metric to maximize was the thermal neutron flux at the inner irradiation sites, while the essential constrain was to maintain the same Onset of Nucleate Boiling Ratio (ONBR) at nominal power, established as general safety criterion. MCNP5 and PLTEMP/ANL codes were used for the neutronics and thermal hydraulics simulations respectively, to analyze the reactor behavior under nearly 300 different core configurations or fuel loading patterns. The main proposed configuration, involving 270 fuel pins and minor modifications to the fuel cage, is predicted to allow a performance improvement of about 72.5% while maintaining the same safety margins. Additional or alternative, more complex modifications of the reactor for even further performance increases, involving changes to the fuel, the annular reflector and the control rod, are also suggested and analyzed in some detail. The basis to reduce or recover safety margin to reach higher power and flux levels, with the potential to at least double current performance when combined with suggested modifications, is also briefly examined. Possible effects of the higher reactor power on the reactor operation are considered as well, providing additional potential modifications to extend the maximum continuous operation time and the period between Be shims adjustments. Overall, this work constitutes a solid and detailed reference basis for very substantial potential performance improvements for SLOWPOKE-2 reactors that are pending conversion to LEU and those that may need refueling in the future. It also points out possible, though foreseeable more limited, performance improvements on MNSR reactors.},
doi = {10.1016/j.anucene.2018.12.016},
journal = {Annals of Nuclear Energy (Oxford)},
number = C,
volume = 128,
place = {United States},
year = {2019},
month = {1}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1016/j.anucene.2018.12.016

Figures / Tables:

Fig. 1 Fig. 1: Core cross section showing fuel pins distribution, power and virtual coolant channels. HEU 296-pins core (left); typical LEU 198-pins core (right)

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.