For Nuclear Electric Propulsion (NEP) applications, gas cooled nuclear reactors with dynamic energy conversion systems offer high specific power and low total mass. This paper describes the Pellet Bed Reactor (PeBR) concept for potential NEP missions to Mars. The helium cooled, 75–80 MWt PeBR, consists of a single annular fuel region filled with a randomly packed bed of spherical fuel pellets, is designed for multiple starts, and offers unique safety and operation features. Each fuel pellet, about 8–10 mm in diameter, is composed of hundreds of TRISO type fuel microspheres embedded in a graphite matrix for a full retention of fission products. To eliminate the likelihood of a single‐point failure, the annular core of the PeBR is divided into three 120° sectors. Each sector is self contained and separate and capable of operating and being cooled on its own and in cooperation with either one or two other sectors. Each sector is coupled to a separate, 5 MWe Closed Brayton Cycle (CBC) energy conversion unit and is subcritical for safe handling and launching. In the event of a failure of the cooling system of a core sector, the reactor power level may be reduced, allowing adjacent sectors to convect the heat away using their own cooling system, thus maintaining reactor operation. Also, due to the absence of an internal core structure in the PeBR core, fueling of the reactor can easily be performed either at the launch facility or in orbit, and refueling can be accomplished in orbit as needed to extend the power system lifetime
Pellet bed reactor concept for nuclear electric propulsion
10th SymposiumùSpace Nuclear Power and Propulsion ; 1993 ; Albuquerque, NM, USA
AIP Conference Proceedings ; 271 , 2 ; 631-639
1993-01-15
9 pages
Conference paper
Electronic Resource
English
FUEL SPHERES , COATED FUEL PARTICLES , CLOSED−CYCLE SYSTEMS , DESIGN , BRAYTON CYCLE , GAS COOLED REACTORS , GRAPHITE , SPACE PROPULSION REACTORS , ZIRCONIUM CARBIDES , ELECTRIC PROPULSION , HELIUM , PYROLYTIC CARBON , REACTOR CORES , URANIUM CARBIDES , REACTOR CONTROL SYSTEMS , REACTOR FUELING , REACTOR SAFETY , PEBBLE BED REACTORS , AFTER−HEAT REMOVAL
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