Reactor noise analysis. Recent research activities in Japan.

Abstract

A review is presented on the recent research activities in Japan in the field of reactor noise analysis. It covers six selected areas: nonlinear stochastic theory and identification of nonlinearity in nuclear reactor dynamics, structural identification via reactor noise analysis, autoregressive model and contraction of information, knowledge-based support system for reactor noise analysis and diagnosis, reactor noise analysis benchmark tests and application of noise analysis to BWR plant diagnosis.

Autoregressive model analysis and decay ratio

“…The method of the AR model is used for a black-box analysis, in which the relationship between physical processes and its model is not made clear. To give a physical foundation of it, we have already examined the properties of the AR model and can summarize them in the following two rules (Kishida, 1988 ;Suda et al, 1989). Let a system be described by an AR-MA (autoregressive moving average) model.…”