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Title: Low Mass SCoRe-S Designs for Affordable Planetary Exploration

Abstract

Fast neutron spectrum space reactors are an appropriate choice for high thermal powers, but for low powers, they need to be large enough to satisfy the excess reactivity requirement while remaining sub-critical when immersed in wet sand and flooded with seawater following a launch abort accident. All Sectored, Compact space Reactors (SCoRe) are fast spectrum reactors. They have a 0.1 mm thick 157Gd2O3 coating on the outer surface of the reactor vessel to reduce the effect of wet sand as a reflector, and 157GdN fuel additive to reduce the effect of thermal neutron fission on the criticality of the flooded reactor following a launch abort event. This paper identifies the SCoRe-S cores with the smallest BeO radial reflector thicknesses which satisfy the reactivity design requirements. These are a cold-clean and hot-clean excess reactivity > $4.00 and $2.00, respectively, at least $1.00 subcritical at shutdown, and when submerged in wet sand and flooded with seawater following a launch abort event. Reducing the radial reflector thickness increases the 157GdN fuel additive but decreases the diameter, and hence the shutdown margin, of the B4C/BeO control drums. The smallest reactor to satisfy the reactivity design requirements is SCoRe-S7, which has a thick BeO radialmore » reflector (15.3 cm), and its mass (425.3 kg) is 21 kg heavier than the next larger SCoRe-S8 core with a thinner BeO reflector of 13.3 cm. The SCoRe-S7 is also 1.5 kg heavier than the SCoRe-S11, with the largest core, but the thinnest radial reflector thickness of 10.7 cm.« less

Authors:
;  [1];  [2]
  1. Institute for Space and Nuclear Power Studies, University of New Mexico, Albuquerque, NM 87131-0001 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
21054541
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 880; Journal Issue: 1; Conference: International forum-STAIF 2007: 11. conference on thermophysics applications in microgravity; 24. symposium on space nuclear power and propulsion; 5. conference on human/robotic technology and the vision for space exploration; 5. symposium on space colonization; 4. symposium on new frontiers and future concepts, Albuquerque, NM (United States), 11-15 Feb 2007; Other Information: DOI: 10.1063/1.2437462; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
22 GENERAL STUDIES OF NUCLEAR REACTORS; BERYLLIUM OXIDES; BORON CARBIDES; CONTROL; CRITICALITY; DESIGN; FAST NEUTRONS; FAST REACTORS; FISSION; FUEL ADDITIVES; POWER SYSTEMS; REACTIVITY; REACTOR VESSELS; SHUTDOWN; SPACE VEHICLES; THERMAL NEUTRONS; NESDPS Office of Nuclear Energy Space and Defense Power Systems

Citation Formats

Hatton, Steven A., El-Genk, Mohamed S., and Dept. Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131-0001. Low Mass SCoRe-S Designs for Affordable Planetary Exploration. United States: N. p., 2007. Web. doi:10.1063/1.2437462.
Hatton, Steven A., El-Genk, Mohamed S., & Dept. Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131-0001. Low Mass SCoRe-S Designs for Affordable Planetary Exploration. United States. doi:10.1063/1.2437462.
Hatton, Steven A., El-Genk, Mohamed S., and Dept. Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131-0001. Tue . "Low Mass SCoRe-S Designs for Affordable Planetary Exploration". United States. doi:10.1063/1.2437462.
@article{osti_21054541,
title = {Low Mass SCoRe-S Designs for Affordable Planetary Exploration},
author = {Hatton, Steven A. and El-Genk, Mohamed S. and Dept. Chemical and Nuclear Engineering, University of New Mexico, Albuquerque, NM 87131-0001},
abstractNote = {Fast neutron spectrum space reactors are an appropriate choice for high thermal powers, but for low powers, they need to be large enough to satisfy the excess reactivity requirement while remaining sub-critical when immersed in wet sand and flooded with seawater following a launch abort accident. All Sectored, Compact space Reactors (SCoRe) are fast spectrum reactors. They have a 0.1 mm thick 157Gd2O3 coating on the outer surface of the reactor vessel to reduce the effect of wet sand as a reflector, and 157GdN fuel additive to reduce the effect of thermal neutron fission on the criticality of the flooded reactor following a launch abort event. This paper identifies the SCoRe-S cores with the smallest BeO radial reflector thicknesses which satisfy the reactivity design requirements. These are a cold-clean and hot-clean excess reactivity > $4.00 and $2.00, respectively, at least $1.00 subcritical at shutdown, and when submerged in wet sand and flooded with seawater following a launch abort event. Reducing the radial reflector thickness increases the 157GdN fuel additive but decreases the diameter, and hence the shutdown margin, of the B4C/BeO control drums. The smallest reactor to satisfy the reactivity design requirements is SCoRe-S7, which has a thick BeO radial reflector (15.3 cm), and its mass (425.3 kg) is 21 kg heavier than the next larger SCoRe-S8 core with a thinner BeO reflector of 13.3 cm. The SCoRe-S7 is also 1.5 kg heavier than the SCoRe-S11, with the largest core, but the thinnest radial reflector thickness of 10.7 cm.},
doi = {10.1063/1.2437462},
journal = {AIP Conference Proceedings},
number = 1,
volume = 880,
place = {United States},
year = {Tue Jan 30 00:00:00 EST 2007},
month = {Tue Jan 30 00:00:00 EST 2007}
}