CFD Analysis of Upper Plenum Flow for a Sodium-Cooled Small Modular Reactor

Conference · Thu Jan 01 04:00:00 EST 2015

OSTI ID:1336451

Kraus, A.; Hu, R.

Upper plenum flow behavior is important for many operational and safety issues in sodium fast reactors. The Prototype Gen-IV Sodium Fast Reactor (PGSFR), a pool-type, 150 MWe output power design, was used as a reference case for a detailed characterization of upper plenum flow for normal operating conditions. Computational Fluid Dynamics (CFD) simulation was utilized with detailed geometric modeling of major structures. Core outlet conditions based on prior system-level calculations were mapped to approximate the outlet temperatures and flow rates for each core assembly. Core outlet flow was found to largely bypass the Upper Internal Structures (UIS). Flow curves over the shield and circulates within the pool before exiting the plenum. Cross-flows and temperatures were evaluated near the core outlet, leading to a proposed height for the core outlet thermocouples to ensure accurate assembly-specific temperature readings. A passive scalar was used to evaluate fluid residence time from core outlet to IHX inlet, which can be used to assess the applicability of various methods for monitoring fuel failure. Additionally, the gas entrainment likelihood was assessed based on the CFD simulation results. Based on the evaluation of velocity gradients and turbulent kinetic energies and the available gas entrainment criteria in the literature, it was concluded that significant gas entrainment is unlikely for the current PGSFR design.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: KAERI (Korea Atomic Energy Research Institute)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1336451
• Country of Publication: United States
• Language: English

Related Subjects

UIS
computational fluid dynamics
gas entrainment
sodium fast reactor
upper plenum