Development of a model for prediction of annular flow and dryout in BWR fuel assemblies with spacers
2005 (English)In: Proceedings of the Eleventh International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, 2005Conference paper (Refereed)
This paper deals with development of a phenomenological annular flow and dryout model for BWR fuel assemblies. The model is based on a solution of conservation equations for mass, momentum and energy for each subchannel in the bundle. Proper closure relations are included to model the inter-subchannel mass, momentum and energy transfer. A fullNewtoniteration scheme is used to solve the algebraic set of finite difference equations. The convergence of the scheme is very robust and it typically takes 5 iterations to find the solution. After finding the flow and enthalpy distribution between all subchannels in a bundle, a newly developed algorithm is applied to calculate the liquid film distribution on channel walls. The algorithm predicts the liquid film flow rate taking into account the local values of the entrainment, deposition and evaporation rates. The spacer influence is taken into account through proper model of intensified deposition rate downstream of spacer locations. The model has been applied for prediction of flow and phase distributions in various fuel assemblies and the results of calculations have been compared to measurements. Good agreement between predictions and measurements has been obtained. The model is also applicable to prediction of dryout occurrence in fuel assemblies, where proper predictions of various effects, e.g. influence of axial power distribution on dryout power, have been obtained.
Place, publisher, year, edition, pages
Dryout, annular flow, BWR fuel assemblies, spacer influence
Research subject SRA - Energy
IdentifiersURN: urn:nbn:se:kth:diva-79217OAI: oai:DiVA.org:kth-79217DiVA: diva2:495251
QC 201203012012-02-082012-02-082012-03-01Bibliographically approved