Natural Circulation Cooling Scram Transient Analysis in Advanced BWRs: Buoyancy Effects

• Published in: Energy sources. Part A, Recovery, utilization, and environmental effects Recovery, utilization, and environmental effects, 2015-01, Vol.37 (1), p.19-27
• Main Authors: Espinosa-Paredes, G., Juárez-Sánchez, M.-A., Nuñez-Carrera, A., Vázquez-Rodríguez, A.
• Format: Article
• Language: English
• Subjects: advanced nuclear reactor; Approximation; Boussinesq approximation; Buoyancy; buoyancy force; Circulation; Cooling; Mathematical analysis; natural circulation; numerical simulation; SCRAM; simplified boiling water reactor; transient behavior; two-phase flow
• ISSN: 1556-7036; 1556-7230
• DOI: 10.1080/15567036.2011.576419

In this study, the transient characteristics of a two-phase natural circulation core cooling in advanced boiling water reactors is investigated during a scram scenario. The natural circulation is controlled by the mean density difference between the coolant inside and outside of the core. The Boussinesq approximation was applied in the momentum equations for two-phase flow analysis that considers the buoyancy force, which is related with thermal effects. The results obtained in transient with the buoyancy force in the core were compared with the standard approximation. The found results for scram transient indicate that, for time-scale, a small trend is practically the same between Boussinesq and standard approximation, where the difference between them is small. However, for higher simulation time (8 to 12 s) the consequences of the drive force effects are appreciable.