ANALYSIS OF METHODOLOGIES FOR THE COUPLING OF MULTI-PHYSICS PHENOMENA IN THE QUASI-STATIC APPROACH TO NUCLEAR REACTOR DYNAMICS

摘要

In the analysis of nuclear reactor dynamics, the quasi-static method often is an acceptableand computationally appealing alternative to the direct numerical integration of the timeandphase-space-dependent balance equations for the neutron flux and the delayed neutronprecursor concentrations. In multi-physics analyses, the quasi-static modelling of neutronkinetics leads to diverse possibilities for the multi-physics coupling scheme, as the feedbackeffects that arise from multi-physics phenomena may intervene on either or both theamplitude and/or the shape component of the flux. A current research activity of theCommissariat à l’énergie atomique et aux énergies alternatives (CEA) involves the studyof methods by which to solve the time- and phase-space-dependent neutronics equationsin the context of multi-physics analyses, together with appropriate coupling schemes.The present work develops and assesses coupling strategies for the quasi-static methodwhen utilised in the context of multi-physics analyses of nuclear reactor dynamics. Thedeveloped methods are characterised through a case study on a reactivity-initiated transientapplied to a light-water reactor motif in reduced three-dimensional geometry.