Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)

Conference · Thu Jul 01 04:00:00 EDT 2010

OSTI ID:991892

Schnitzler, Bruce G; Borowski, Stanley K

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature profiles in the engines. Engine performance can be improved by some combination of propellant flow control at the fuel element level and by varying the fuel composition. Enrichment zoning at the fuel element level with lower enrichments in the higher power elements at the core center and on the core periphery is particularly effective. Power flattening by enrichment zoning typically results in more uniform propellant exit temperatures and improved engine performance. For the SNRE, element enrichment zoning provided very flat radial power profiles with 551 of the 564 fuel elements within 1% of the average element power. Results for this and alternate enrichment zoning options for the SNRE are compared.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: OTHER
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 991892
• Report Number(s): INL/CON-10-19398
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
DESIGN
ECONOMICS
ENGINES
EXPLORATION
Enrichment
FISSILE MATERIALS
FUEL ELEMENTS
LANL
NASA
NESDPS Office of Nuclear Energy Space and Defense Power Systems
Nuclear
PERFORMANCE
PROPULSION
PROPULSION SYSTEMS
ROCKET ENGINES
ROCKETS
Rocket
SECURITY
TOLERANCE
TRANSPORT
TRANSPORTATION SYSTEMS
Zoning