NTP Engine System Design and Modeling

Hybrid Temperature-Reactivity PID Controllers for Nuclear Thermal Propulsion Startup

“…Therefore, unless the gains are made time-dependent (as in Ref. [2]), a simple PI controller cannot perfectly anticipate any sudden change in demand. A derivative term adds anticipation and can also reduce overshoot but, in real systems, it can lead to instabilities due to instrumentation noise.…”

“…Note however that this is likely due to using constant gains as opposed to what was done in Ref. [2]. Figure 5 shows the results obtained with a temperaturedriven PD controller (K p = 5 × 10 −3 deg/K, K d = 5 × 10 −3 degs/K).…”

“…Previously, a standard proportional integral (PI) controller for temperature and pressure demands was used in Ref. [1], with delays and oscillations being observed after any sudden change in demand. With the controller gains adjusted as a function of total power, near-perfect agreement between the demands and the responses was obtained [2].…”

“…[1], with delays and oscillations being observed after any sudden change in demand. With the controller gains adjusted as a function of total power, near-perfect agreement between the demands and the responses was obtained [2]. Simultaneously, a limited delay and little to no overshoot were obtained in Ref.…”