j. starflinger, c. graß, r. kulenovic, a. schaffrath, m ... · • loss of ultimate heat sink, •...
Post on 07-Sep-2019
6 Views
Preview:
TRANSCRIPT
Institute of Nuclear Technologyand Energy Systems
Experimental and Analytical Investigation of the Performance of Heat Pipes for Residual Heat Removal from Spent Fuel PoolsJ. Starflinger, C. Graß, R. Kulenovic, A. Schaffrath, M. Pöhlmann, T. Fuchs
Annual Meeting on Nuclear Technology, Hamburg, May 10-12, 2016
• Loss of ultimate heat sink,
• Station blackout,
• Loss of infrastructure
• Loss of human ability to deal with the catastrophe beyond personal experience
• The second principle of reactor safety „cooling of nuclear fuel“ must be assured even under severe accident conditions
also for wet storage pools, preferably with passive devices!
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 2
MotivationFukushima Follow-up
Source: Tepco
• Active Cooling• Two strands of the emergency and residual heat removal system (TH)• Active components (pumps, valves, etc.)• Servicing, maintenance, periodic inspection• Time and cost-intensive, particularly in the long-term use!
• Passive Cooling• No active components, control system or operator intervention• Based upon physical principles (buoyancy, etc.)• IAEA Category B of passivity can be reached• Lower failure probability, advantages in operating costs,
particularly in long-term use !
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 3
Active vs. Passive CoolingSpent Fuel Pool Cooling
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 4
Principle of OperationHeat Pipes – Passive Heat Removal Device
heat input
vapour
liquid
evaporation condensation
capillary structure
heat output
evaporator zone adiabatic zone condenser zone
Heat Pipe (with capillary structure)
Thermosiphon(without capillary structure)
• Copper heat pipe (filled with water) and full metal copper rod tug in a glass bowl
• Warm water spilled into the bowl
• Heat transfer through the heat pipe almost instantaneously.
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 5
Demonstration of OperationHeat Pipe
Video: C. Graß, W. Flaig, IKE
Copper Rod Heat Pipe
Glas Bowl
• Selection of working fluid results from the operational temperature range
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 6
Working FluidsHeat Pipes – Passive Heat Removal System
NaLi
Ag
KCs
NH3
C3H8
CH4
H2
Hg
H2OCH4O
C2H6
N2
Freon
Diphenyl, Toluol
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 7
Application for Sensor Cooling (≈1100°C environment temperature)Heat Pipes
Cooling
Heat Pipe
Insulation
Heating
Heat Pipe Test Lab. at IKE
http://www.zim-bmwi.de/erfolgsbeispiele
Sensor-cooling with heat pipes
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 8
Large-Scale Application: Heat ExchangerHeat Pipes
http://www.econotherm.eu/downloads/gas_to_air.pdf
375 Heat PipesHigh redundancy!
measures (estimated): 1500 x 1500 x 3000mm
Cold combustion air
Preheatedcombustion air
Hot exhaust gas
Cooledexhaust gas
Heat pipe heat exchanger
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 9
Master-Thesis by M. Eng. C. GraßPassive Heat Removal System for Generic Spent Fuel Pools
Spent Fuel Pool
Bundles ofHeat Pipes
Air
Air• Passive heat removal from
spent fuel pool to air driven by natural convection
• Heat pipes suspended from the top, no penetrations of pool walls
• Heat pipes will have at least two elbows
• Develop a numerical tool for steady state heat removal calculation from a wet storage pool to the air by means of heat pipes / thermosiphons
• Selection of the appropriate working fluid
• Simulation of operation performance
• Identify open points
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 10
Objectives
• Pool temperatures provided by KTA:
• Coarse geometrical and power data taken from spent fuel storage pool in NPP Gösgen, Switzerland „Masterpiece“
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 11
Boundary Conditions
Operation Conditions
Heat Source / °C
Heat Sink / °C
Driving Force (Temperature difference) / °C
Normal 45 26 19
Abnormal 60 28 32
Accident 80 32 48
• Heat balance between pool and atmosphere
• Chain of iteration loops for the system temperatures along the heat transfer from source to sink
• Equations according to VDI-Wärmeatlas, Section MI, and open literature
• Examination of the performance limits and the modelled performance of the heat pipe
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 12
Steady State Heat BalanceNumerical Iteration Scheme
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 13
Selection of Working Fluid - Figure of MeritHeat Pipes
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 14
Selection of Working Fluid - Figure of MeritThermosiphons
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 15
Example: Results for 40mm pipeSteady State Heat Removal
• Compared to heat pipes, power transferred is higher for thermosiphons because of less friction
≈ 20% difference
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 16
Operation Limits of Heat Pipes / Thermosiphons
• Counter Current Flow Limitation (CCFL) in the order of 4 – 6 kW
• Both heat pipes and thermosiphons have performance margins up to a factor of four.
Example: Results for 40mm pipe
• Feasibility: Heat pipes / thermosiphons are suitable to transfer decay heat from wet storage facilities into the diverse ultimate heat sink (air)
• Dimensions: Length at least 12m (construction reasons)
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 17
Summary of Results
Condenser Zone
Evaporator zone
Adiabatic zone
Inclination
> 1 m
> 6 m
> 5 m
• Support of Gravity: Heat pipes shall be manufactured as thermosiphons without capillary structure. Inclination of adiabatic section >5°.
• Conservatism: With increasing temperature difference, more heat is transported through the heat pipes.
• Heat Transfer Limit: Air side (condensation zone of heat pipe) Measures necessary (e.g. fins, chimney effect).
• Open points:
• Long heat pipes with elbows. High pressure loss? There are no validation data available for long heat pipes.
• In ATHLET (or other system codes) there is no validated modelavailable of heat pipes.
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 18
Summary of Results
• Three year project, start: Dec. 1, 2015
• Funded by BMWi (FKZ 1501515 and RS 1543)
• Scope: • Experiments in laboratory and in realistic environment providing
validation data• Derivation of a correlation for long heat pipes, based upon
experimental laboratory data • Set-up and validation of a mechanistic model of heat pipes in ATHLET• Benchmark of wet storage pool cooling (mechanistic model vs.
correlation)
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 19
Cooperation between GRS and IKE (and AREVA)Project PALAWERO / Heat Pipes
• Planned single heat pipe experiments: • Pipes straight up (base case)• Pipes with two elbows and
different inclination• Different diameters• Different working fluids• With and without capillary
structures
• Validation data base with well defined boundary conditions!
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 20
Laboratory experimentProject PALAWERO / Heat Pipes
4 m
8 m
Water pool (heated)
Water pool (heated)
IKE laboratory hall
Cooling through cryostat
Basement
Ground floor
Roof
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 21
Experiment under realistic environmental boundary conditionsProject PALAWERO / Heat Pipes
IKE and GRS like to thank the Federal Ministry of Economic Affairs and Energy for supporting the projects PALAWERO / Heat Pipes (FKZ 1501515 and RS 1543)
12/5/2016University of Stuttgart – Institute of Nuclear Technology and Energy Systems 22
Acknowledgements
Thank you!
e-mailphone +49 (0) 711 685-fax +49 (0) 711 685-
University of Stuttgart
Pfaffenwaldring 31 • 70569 Stuttgart • Germany
Prof. Dr.-Ing. Jörg Starflinger
6211662008
Institute of Nuclear Technology and Energy Systems (IKE)
joerg.starflinger@ike.uni-stuttgart.de
Institute of Nuclear Technologyand Energy Systems
top related