Natural convection flow in a cask storage warehouse For Toyo Engineering PHOENICS Version : DETAILS : BFC grid Three-Dimensional steady flow with heat transfer Buoyancy-influenced flow Surface to surface radiation included NX*NY*NZ=288*74*42=895,104 NOTES : The purpose of this model is to establish the temperature distribution and the air flow rate.

Geometry x-y plane nx×ny=288×74 x-y plane nx×nz=288×42

outlet Heat source : 22.6[kw] Air in Air out cask External temperature 23.2 External temperature 23.2 Q A2A2 A1A1 A1A1 A2A2 Q Radiation model in the cask

Result

Velocity FlowRate[m3/s] per one cask Experimental data Result of PHOENICS

Temperature

Natural convection flow in a nuclear reactor For Denchuken PHOENICS Version : 3.6 DETAILS : Cylindrical-polar grid Three-Dimensional steady or transient flow with heat transfer Buoyancy-influenced flow Surface to surface radiation included NX*NY*NZ=40*45*80=144,000 NOTES : When an accident happens in the nuclear system, eg the cooling system may fail. Hence, heat will be released solely by natural convection of air flow. The purpose of this model is to establish the distribution of temperature and the air flow rate under these circumstances.

PRACS IHX(Heat sink Q=-28.55[MW]) Liquid Na convection zone Pump(11m 3 /min) Steady::on Transient::off Radial shield Reflector Argon gas zone Air convection zone Air inlet (connected to stack) Air outlet (connected to stack) Air Flow Liquid Na Flow Core (Heat source Q=30[MW]) Structure of porous media zone

Boundary conditions Heat source and Heat sink: Steady:-28.55[MW] Transient:0[WM] Steady:30[MW] Transient: change profile

Pump power : Steady:11[m 3 /s] Transient: change profile.

Body force (Buoyancy): Liquid Na convection zone Air convection zone

Resistance force in the porous medium zone: where K: Pressure resistance coefficient. (This is different in each zone) ρ:density U velocity

Radiation : Q2Q2 Q1Q1 radiation Q A2A2 A1A1 A1A1 A2A2 Q

Energy source in the porous medium zone : where

Pressure value in the air convection zone boundary : P ITOP i A i [m 2 ]k i [-]n i=1 to 5 i=6 to 10 The value of pressure in the air convection zone boundary is renewed while it is calculated from the next experience equation. P OTOP ΔP f1 ΔP f2 ΔP f3 ΔP f4 ΔP f5 ΔP f6 ΔP f7 ΔP f8 ΔP f9 Δh out Δh in P OUT P IN Δh

Result

Temperature distribution (steady) Maximum temperature [ ] Experimental data Result of PHOENICS

Pressure distribution (steady) Pressure drop [MPa] in Na convection zone Experimental data Result of PHOENICS

Air flow rate in the air convection zone. Maximum temperature in the liquid Na convection zone.

Transient simulation in a vapor turbine PHOENICS Version : DETAILS : Cartesian grid Three-Dimensional transient flow NX*NY*NZ=222×218×98=4,742,808

Inlet of vapor Outlet Air :Fixed temperature Nozzle Box : Fixed temperature

RESULT

90° 0° 30° 60° 120° 150° 180° SLICE POINT1 POINT2