Download or read book Next Step in the Evolution of the Nuclear Thermal Rocket written by Lucas Fischhaber and published by . This book was released on 2013 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Nuclear Engine for Rocket Vehicle Application (NERVA) and Rover program built and tested 23 reactors with a total run time of 107 hours at full power operation from 1955 to 1972. Towards the end of the NERVAJRover program, a fuel test bed reactor called the NERVAderived Pewee was operated at 507 MW and achieved highest specific impulse, peak fuel temperature, average coolant exit temperature, and core average power density. The NERVAderived Pewee, using NbC or ZrC clad graphite fuel, set new performance milestones for the program. However, it did not solve the major limiting factors caused by graphite fuel. These fuel elements are susceptible to corrosion from hot hydrogen and require structural support throughout the reactor core which adds weight. Tungsten based ceramic-metallic is a different type of fuel, first conceptualized in 1955, that addresses the issues with graphite. A CERMET fuel matrix does not corrode from hot hydrogen and does not require structural support. Additionally, it is capable of reaching fuel centerline exit temperatures of 3,000 K without melting increasing thrust potential. This study utilizes, as a starting point, the physical dimensions of the NERVA-derived Pewee and exchanges graphite fuel (density 0́43.475 g/cm3) with a CERMET fuel (density 0́415.158 g/cm3) matrix while making few adjustments to the core length and position of the control drums. The objective for this study is to compare graphite and CERMET fuels within the environment of the NERVA-derived Pewee using energy per fuel element, thrust to weight ratio, and specific impulse to measure differences. A secondary objective is to investigate sensitivity of the re-designed Pewee0́9s performance from varying CERMET fuel thermal conductivity. Performance for all re-designed Pewee CERMET fuel reactors had low sensitivity in fuel thermal conductivity. Thrust to weight ratio varied a maximum of 3.47 percent when changing the thermal conductivity multiple by 75 percent from 0.5 to 2.0. Maximum performance for the NERVA-derived Pewee with graphite fuel had a specific impulse of 916, a thrust to weight ratio of 5.85, and a MW per fuel element of 1.147 at a reactor pressure loss of 185 psi. Re-designed Pewee with CERMET fuel out-performed graphite fuel with a specific impulse of 957, thrust to weight ratio of 8.56, and MW per fuel element of 1.248 at a reactor pressure loss of 186 psi.