The Measurement of Reactivity

The use of a general purpose analog computer for the continuous measurement of reactivity of a nuclear reactor is described. The machine is programmed to solve the conventional space-independent reactor kinetics equations for reactivity using the signal from an ion chamber as input data. This technique provides reactivity information instantaneously and continuously. Using it, one can calibrate control rods “on the run,” and can measure stationary values of reactivity without waiting for asymptotic periods to develop.