Development of Low-Pressure Loss Separator for Advanced BWRs

Abstract In Boiling Water Reactors, steam water mixture is produced by the reactor core. Steam separators separate the steam from the water downstream the core. The steam separators are designed to provide good steam-water separation ratio (limit the carry-over ratio of liquid water in steam and carry-under ratio of steam in water) without inducing too large pressure loss on the recirculation flow (affecting core flow rate or pump power). The steam separators use flow rotation and centrifugal force to separate water from the steam. Good steam-water separation requires stronger rotation within the barrel, which usually increases the pressure loss presenting a trade-off. Many studies have aimed at both improving the separation performance and lowering the pressure loss. This work introduces recent activities of Hitachi-GE Nuclear Energy. A previously developed prototype was optimized to further improve performance as well as manufacturability by taking the advantage of quick prototyping with CFD modelling, 3D printer prototyping and half-scale air-water testing at room temperature and atmospheric pressure. The final design prototype will be confirmed with a test that is being planned in Hitachi Utility Steam Test LEading facility (HUSTLE) under nominal BWR operating conditions. Confirming the separator performance will allow adopting the separator in future advanced BWR plants or potential replacement of older separators in operating BWR plants. The adoption of the low-pressure loss separator would lead to improved plant performance and safety.