Presentation on theme: "Nuclear Thermal Hydraulic System Experiment"— Presentation transcript:
1 Nuclear Thermal Hydraulic System Experiment Nuclear and Hydrogen System Laboratory, KAIST
2 Fukushima accident Earth quake Reactor shut down Electricity supply from grid is failedEmergency diesel generator is also failedSubmerged by TsunamiReactor Coolant Pump is turned offThermal energy couldn’t be removedMost of safety systems were dependent on electricityFuel melt / Hydrogen explosion / heat up of spent fuel pool
3 Nuclear Safety Systems Systems that required to remove the decay heat under the postulated accidentex ) Safety Injection system (Inject water to the primary loop during accient)After Fukushima, following requirement were added to the safety systemsSystem should remove the decay heat even without electricityWe call this system as “Passive safety system”Usually gravity is used for the driving force of passive safety system
4 Nuclear Power Plant accident A number of systems(Thermal hydraulic systems)ThermalEnergyFromFuel rod(from atomic decay)“Decay heat”ElectricEnergyFuel rodsHeat should be removedSafety system
5 Passive Containment Cooling System Passive system that removes decay heat by cooling the steam/air in the containmentDecay heat(Steam)Decay heatHow can we measure and calculate the performance of this system Experiment for PCCS
6 PCCS TestPurposeTo calculate heat removal capacity and heat transfer coefficient of the condensing tubeCheck the effect of the Air/Steam FractionCheck the effect of the Pressure
7 PCCS Test Facility Main test section Chambers : Heat exchangers Steam GeneratorPCCT and Cooling water pipesChamber :Air/Steam mixtureSGPCCT
8 Experiments Procedure 1. Set up test conditionSteam pressure of the steam generatorAngle of the condensing tube (Already Fixed)Temperature of cooling water (inlet)Mass flow rate of cooling water2. Open the valve of SG connected to the chamber3. Measure or set the properties of systemSystem pressure and temperatureOutlet temperature of cooling water4. Calculate heat capacity and heat transfer coefficient5.Open the venting valve on the chamber for 1 min and close itAir/Mass Fraction of the System changed ( for next Exp. Case.)6.Repeat previous steps
9 Experiments Procedure Steam generator2 ,3 and 4 bar saturated condition (one pressure condition for one group)Cooling waterPressure: 1 bar(atmosphere)What you measure? Or check?Temperature of cooling water in / outMass flow rateTwallChannel geometry informationOuter diameter of pipe = 49.1 mmInner diameter of pipe = 40 mmLength of pipe = 0.7 m
10 Heat transfer rate and heat transfer coefficient Heat transfer rate : Amount of heat transferred per timeSingle-phase fluid** Mass flow rate,
11 Heat transfer rate and heat transfer coefficient Heat transfer coefficient : Amount of heat transferred per time, per area, and per temperature differenceTwallTbulkHeat transfer coefficient is affected by: Geometry / Angle / Materials / Air-mass fraction / Pressure ….
12 Heat transfer rate and heat transfer coefficient Heat transfer rate : Amount of heat transferred per timeSingle-phase fluid
13 Notes Your Report Should includes Clear Conditions for each case Air / Steam Fraction of each experiments (Through the calculation)Heat Transfer Coefficient of PCCS for each case and the reason for the difference between each case.