Nonlinear stability analysis of boiling water reactors on the basis of system codes and reduced order models

摘要

BWR stability analysis at PSI, as at other research centers, is usually carried out employing complex system codes. These do not, however, allow detailed investigation of the complete manifold of possible solutions of the nonlinear differential equation set involved. A novel analytical, so-called reduced-order model for BWR stability analysis is currently under development at PSI, as a PhD thesis and in collaboration with the University of Illinois, Urbana-Champaign, USA. Bifurcation analysis carried out with this model is expected to provide valuable insights into the physical phenomenology of BWR stability behaviour. This article presents the motivation and the basic principles of this methodology, as also an example of an interesting result concerning bifurcation analysis.