Measurement of Prompt Neutron Decay Constant in Esfahan Light Water Subcritical Reactor Utilizing Feynman-α Analysis

Diagnostic methods based on zero power reactor noise theory are very common and widely applicable in kinetic parameters and are also one of the standard diagnosis methods of nuclear reactor cores. Feynman-α method is one of these efficient methods of diagnosis. In this work, this method is employed to measure the prompt neutron decay constant of the Esfahan Light Water Subcritical Reactor (ELWSCR). The ELWSCR is a deep subcritical reactor. Therefore, the prompt neutron decay constant of the core is a large negative quantity. Using an especial data acquisition system, the prompt neutron decay constant of the core, based on the Feynman-α analysis, is estimated to be 3966±88 sec-1. The time window of 100 µs is employed in this investigation. By applying the Rossi-α method, this parameter has alrealy been reported to be 3990±177 sec-1 in references. The comparison shows that our results are in a rather good agreement with that estimated by the Rossi-α method within the range of statistical uncertainties.