Bimodal, Low Power Pellet Bed Reactor System Design Concept

El‐Genk, Mohamed S.; Liscum‐Powell, Jennifer; Pelaccio, Dennis G.

doi:10.1063/1.2950175

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…For PoD reactor designs operating at low thermal power (<500 kWt) for up to 10 yr, a TRISO-type minisphere design (4-6 mm in diam) is preferred. 33 This fuel element design provides high fuel loading in the core to satisfy the excess reactivity requirement at BOM as well as results in smaller reactor size and mass. The basic design and coating materials of the fuel minispheres are identical to those for the TRISO-type microspheres with silicon carbide (SiC) coating.…”

Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

“…The maximum fuel burnup expected in the 40-kWe point design of the BM-PeBR system is less than 1.0 atom %, and about four times less in the 10-kWe system. However, for conservative design considerations, the minispheres are designed for a fuel burnup of 2 atom % and maximum temperature of 1600 K. 33 The maximum stress in the SiC coating of the minispheres when loaded with UC and UO 2 fuel is about 73% and 20% of the design stress of the coating, respectively. 33 The fuel material considered for the PoD point designs of the BM-PeBR is either uranium dioxide (UO 2 ) or uranium monocarbide (UC), since their fabrication techniques are known and they have an extensive irradiation data base.…”

Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

“…However, for conservative design considerations, the minispheres are designed for a fuel burnup of 2 atom % and maximum temperature of 1600 K. 33 The maximum stress in the SiC coating of the minispheres when loaded with UC and UO 2 fuel is about 73% and 20% of the design stress of the coating, respectively. 33 The fuel material considered for the PoD point designs of the BM-PeBR is either uranium dioxide (UO 2 ) or uranium monocarbide (UC), since their fabrication techniques are known and they have an extensive irradiation data base. Despite their good irradiation stability, thermal cycling during bimodal operation would cause UC and UO 2 to crack, increasing fission gas release.…”

Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

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Pellet bed reactor concepts for nuclear propulsion applications

El‐Genk

Morley

Pelaccio

et al. 1994

Journal of Propulsion and Power

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Pellet bed reactor (PeBR) concepts have been developed for nuclear thermal and nuclear electric propulsion, and bimodal applications. This annular core, fast spectrum reactor offers many desirable design and safety features. These features include high-power density, small reactor size, full retention of fission products, passive decay heat removal, redundancy in reactor control, negative temperature reactivity feedback, ground testing of the fully assembled reactor using electric heating and non-nuclear fuel elements, and the option of fueling on the launch pad, or fueling and refueling in orbit. In addition to these features, the concepts for nuclear electric propulsion and for bimodal power and thermal propulsion have no single point failure. The average power density in the reactor for nuclear thermal propulsion ranges from 2.2 to 3.3 MW/1 and for a 15-MWe nuclear electric propulsion system the total power system specific mass is about 3.3 kg/kWe. The bimodal-PeBR system concepts offer specific impulse in excess of 650s, tens of Newtons of thrust, and total system specific power ranging from 11 to 21.9 We/kg at the 10-and 40-kWe levels, respectively.

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Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

Section: Pebr Design Concepts For Bimodal Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Pellet bed reactor concepts for nuclear propulsion applications

El‐Genk

Morley

Pelaccio

et al. 1994

Journal of Propulsion and Power

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“…Possible choices of the nuclear reactor heat source are gas cooled (Liscum-Powell and El-Genk, 1994a,b;El-Genk, Liscum-Powell and Pelaccio, 1994), liquid-metal cooled (Truscello and Rutger, 1992;El-Genk et al, 2005), and heat pipes-cooled (Poston, Kapernik and Guffee, 2002;El-Genk and Tournier, 2004a,b). The technology options currently being considered for fractionally converting the reactor thermal power to electricity are advanced thermoelectrics (TE) (El-Genk, Saber and Caillat, 2002), Closed Brayton Cycle (CBC) engines (Barrett and Reid, 2004), potassium Rankine Cycle (PRC) (Yoder and Graves, 1985;Bevard and Yoder, 2003), and Free Piston Stirling Engines (FPSEs) (Thieme and Schreiber, 2004).…”

Section: Introductionmentioning

confidence: 98%

Radiator Heat Pipes with Carbon-Carbon Fins and Armor for Space Nuclear Reactor Power Systems

Tournier¹,

El‐Genk²

2005

AIP Conference Proceedings

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Technologies for Space Reactor Power Systems are being developed to enable future NASA's missions early next decade to explore the farthest planets in the solar system. The choices of the energy conversion technology for these power systems require radiator temperatures that span a wide range, from 350 K to 800 K. Heat pipes with carbon-carbon fins and armor are the preferred choice for these radiators because of inherent redundancy and efficient spreading and rejection of waste heat into space at a relatively small mass penalty. The performance results and specific masses of radiator heat pipes with cesium, rubidium, and potassium working fluids are presented and compared in this paper. The heat pipes operate at 40% of the prevailing operation limit (a design margin of 60%), typically the sonic and/or capillary limit. The thickness of the carbon-carbon fins is 0.5 mm but the width is varied, and the evaporator and condenser sections are 0.15 and 1.35 m long, respectively. The 400-mesh wick and the heat pipe thin metal wall are titanium, and the carbon-carbon armor (~ 2 mm-thick) provides both structural strength and protection against meteoroids impacts. The cross-section area of the Dshaped radiator heat pipes is optimized for minimum mass. Because of the low vapor pressure of potassium and its very high Figure-Of-Merit (FOM), radiator potassium heat pipes are the best performers at temperatures above 800 K, where the sonic limit is no longer an issue. On the other hand, rubidium heat pipes are limited by the sonic limit below 762 K and by the capillary limit at higher temperature. The transition temperature between these two limits for the cesium heat pipes occurs at a lower temperature of 724 K, since cesium has lower FOM than rubidium. The present results show that with a design margin of 60%, the cesium heat pipes radiator is best at 680-720 K, the rubidium heat pipes radiator is best at 720-800 K, while the potassium heat pipes radiator is the best performer and lightest at higher temperatures > 800 K.

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“…(g) Operation reliability: it is best achieved through a combination of redundancy in energy conversion and avoidance of a single point failure in the reactor cooling. Space reactors cooled with circulating liquid metals or gases such as He-Xe, or He, could be designed for avoidance of a single point failure using sectored cores (Liscum-Powell and El-Genk, 1994a,b;El-Genk et al, 1994a. A major challenge in the design of a SRPS is attaining high level of reliability to ensure safety, a long operation life of 10-15 years, and a high specific electric power (>25 W e /kg), while keeping the system light and small.…”

Section: Introductionmentioning

confidence: 99%