Bifurcation Analysis Using the System Code RAMONA

Abstract

This paper presents a study in which the bifurcation analysis is carried out using the system code RAMONA. As a first step, a correspondence hypothesis is proposed to underline the relationship between a stable (unstable) limit cycle solution and the occurrence of supercritical (subcritical) Hopf bifurcation in the modeling of boiling water reactor stability behaviour. A detailed local bifurcation analysis is then carried out in the narrow environment of one representative operational point for the Leibstadt NPP. Based on the experience acquired during stability and bifurcation analyses using our reduced order model, the results found using RAMONA could be explained. As a result, this is the first time that the occurrence of a subcritical Hopf bifurcation has been identified using RAMONA, or any other system code.