Application of variance-to-mean method to accelerator-driven subcritical system

To apply the variance-to-mean method to the pulse-mode operation of the accelerator-driven subcritical reactors, a new formula for the repetition injection of pulsed neutrons has been derived based on the Master equation. Its validity has been confirmed by the numerical simulation and the experiment performed at the Kyoto University Critical Assembly. As a result, in spite of the ADS operation modes, namely the steady state or the pulse injection, the variance-to-mean method is applicable to evaluate the prompt neutron decay constant as a measure of subcriticality. (author)