Subcritical Reactivity as Determined from Reactor Noise

In an earlier paper we proposed a method for the measurement of subcritical reactivity utilizing reactor noise. The theory has now been applied to the analysis of data obtained with the Berkeley TRIGA Mark III Reactor. A two-delayed-group approximation was found necessary to fit parameters in the expression for the variance-to-mean ratio of the neutron counting distribution. Results were found to be in good agreement with those from control rod calibrations.