Application of noise analysis in nuclear safeguards and in the diagnostics of current and future reactor systems

Paper i proceeding, 2011

Neutron fluctuations in both low power systems and power reactors carry important information about the system. The origin of the fluctuations is different in these two regimes; at low power it is the branching (multiple generation of several neutrons in fission) and in power reactors it is the technological processes of random character, such as boiling of the coolant, vibration of mechanical structures etc., which induce the neutron noise. Both the mathematical description and the fields of application differ for these two cases. Common to them is that neutron fluctuations can be used to diagnose the state of the system, either by determining some of its parameters, or by detecting beginning anomalies. In this paper the principles and applications of both zero power noise and the power reactor noise will be given. The theory and application of zero power noise analysis for determining subcritical reactivity in traditional and accelerator driven systems, as well as for detecting, identifying and classifying nuclear materials in nuclear safeguards will be described first. Then the methodology and application of neutron noise analysis in power reactors for solving various diagnostic tasks in traditional and some Generation-IV reactors will be given.