Nuclear Rocket Engine Dynamics Study

Start-up studies are reported considering first just the temperature coefficient of reactivity associated with the fuel temperature, and second, just the density coefficient of reactivity associated with the hydrogen density in a control region. Preliminary results are given of a non-simultaneous digital-analog study of start-up which utilizes a detailed digital code description of heat transfer and fluid dynamics, and an analog description of reactor kinetics and controls. Thrust maneuvering capabilities are explored and used as a basis for comparing control designs. Both fast and slow controllers capable of maintaining propellant exit temperature with + 50°R are discussed.