Tritium Inventories and Containment Philosophy for the Fuel cycle of ITER I. R. Cristescu 1), I. Cristescu 1), L. Doerr 1), M. Glugla 1), D. Murdoch 2) 1), Tritium Laboratory, Germany 2) EFDA CSU Garching, Germany IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 1
Outline of the presentation Tritium Inventories in The Fuel cycle of ITER TRIMO dynamic software for tritium inventory simulation in ITER Minimization of tritium inventories in FC of ITER Tritium confinement principles Detritiation systems Atmosphere Detritiation system Water Detritiation system Closing remarks IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 2
Simplified Block Diagram of the ITER Fuel Cycle TORUS HALL TRITIUM BUILDING Gas Injection System D 2 DT T 2 Storage and Delivery System D2 NBI NBI and Diagnostic NBI D D 2 DT T NBI 2 2 Isotope Separation System H 2 Water Detritiation System HTO H2 to stack Vacuum Pumping Pellet Injection System T 2 Tritium Exhaust Processing N-VDS IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 3
Dynamic Mathematical Modeling of the ITER Fuel Cycle Motivation to develop a dynamic code for FC functioning: ITER is a pulse machine, operating under burn and dwell 450s (3000s) during burn fuel is introduced, 1350s (9000s) during dwell no fuelling is taking place Necessity to support the detailed system design by validated codes Calculation of systems performance under different operational conditions An ITER fuel cycle simulation model has to address the following topics: To evaluate the behavior of the sub-systems in dynamic regimes (operating scenarios), whether the sub-systems, equipment sizes were appropriate (or properly designed). To assess the cycle time from injection back to the storage and delivery system To assess tritium inventories in each subsystem in different operating conditions, taking into account the tritium inventory history of the sub-systems IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 4
Dynamic Mathematical Modeling of the ITER Fuel Cycle Several steps to develop a dynamic code for FC of fusion machines have been made Residence-time approach gives high uncertainties CFTSIM model (2000, under ITER supervision) built on elements from FLOSHEET (CD steady state) and DYNSIM (dynamic simulator) Source code of CFTSIM transferred to TLK in 2004 TRIMO Build on elements from CFTSIM (mainly ISS) Extensive work have been carried out to implement on-going changes in FC design Developed with EFDA support Source code owned by TLK Draft documentation issued IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 5
Software life-cycle diagram - TRIMO Requirements Specification To quantify time variation of T inventories in the Fuel Cycle for several operational scenarios Functional Specification User-friendly graphical interfaces for input parameters Graphical outputs: T inventories, streams composition and flowrates Architectural Design Modular structure: for each FC subsystem a module is assigned Detailed Design Library for hydrogenic isotopes mixtures properties at low temperatures (non-idealities) Coding and Implementation Documented (logical diagrams) Integration Testing and Commissioning Modular tests: CD column module WDS module Operation, Maintenance and Enhancement IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 6
FC design - TRIMO FC Subsystem Fuelling Physical and chemical processes Freezing of DT gas Pressurized gas flows Inflows Outflows Model Design characteristics SDS Torus Lump Fuelling pattern Neutral Beam Injection Torus Vacuum pumping Tokamak Exhaust Processing Vacuum flows Plasma Plasma-wall interactions Charge exchange Retention SDS Fuelling, NBI Torus, TEP Vacuum pumping Vacuum flows Torus TEP Permeation Flows Chemical reactions Vacuum pumping,nbi Lump, parametric, vacuum flows Lump, power-law pressure, parametric Lump, regeneration, Vacuum flows Regeneration pattern, roughing pump characteristics Power, Volume, Burn-up rate, Wal temperature Regeneration pattern, cryopump characteristics, duct geometry, roughing pump characteristics ISS Lump, parametric Pumps characteristics, buffer vessels Water Detritiation System Catalytic isotopic exchange Electrolysis Storage tanks, ISS ISS, Stack Dynamic 1-dimensional mass transfer in mixtures Column height, diameter, temperature, pressure, eletrolyser inventory, separation performances Isotope Separation System Cryogenic distillation TEP,WDS SDS, WDS Dynamic Multicomponen distillation Columns height, diameter, temperature, pressure, inventory, separation performances, intercolumn flows, flow control valves, equilibrators Storage and Delivery System Adsorbtion, release from storage beds ISS Fuelling, NBI Lump, parametric Fuel handling strategy, Buffer vessels imension, storage beds capacity, release rate IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 7
ISS Inventory IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 8
Dynamics of Fuel cycle Inventories IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 9
Tritium needed for operation 120 Pam 3 /s 50%DT basic fuelling scenario for ITER Tritium necessary for noninterrupted burn/pulse Tritium recovered during burn /pulse Tritium recovered during dwell /pulse Longpulse 480g 135g 345g* Shortpulse 72g 12g 60g * * tritium trapped in Torus and as tritiated impurities should be subtracted What influences the speed of tritium recovery in FC: Tritium trapped in Torus Vacuum pumping system regeneration pattern Tritium trapped as impurities CQ 4, Q 2 O Ability of TEP, ISS to process the fuel fast Values of packing hold-up, CD column boiler inventory Control system of ISS ISS design IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 10
T consumption and inventories within FC Besides the tritium from the FC, additionally 1 kg of tritium in Long Term Storage 0.39g T/450s burnpulse with a total burntime/ 10 years = 0.15 years Estimated total tritium consumption for ITER lifetime = 16 Kg 500 450 400 350 300 gfedcb gfedcb gfedcb gfedcb gfedcb gfedcb gfedcb gfedc gfedc Total SDS ISS Vacuum Pumping TEP Torus Fuelling In_Out Tritium Plant Typical analysis where TRIMO is used: 200 Trade-off studies (ISS-TEP, WDS-ISS) 150 Various operational scenarios 8 typical fuelling cases at various T/D 100 50 0 ratio and total flow rates for both short 0 10,000 20,000 Time(s) and longpulse 30,000 Tritium inventory procedure in ITER Evaluations of tritium inventory on various FC configuration (e.g. processing of ablated gas from pellet injector in ISS) Fuel handling in SDS for buffer vessels minimization The ultimate goal of these analysis is ensuring the FC functionality with tritium inventories minimization IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 11 g 250
Validation on sub-systems: WDS and ISS WDS for ITER CECE process Solid polymer electrolyser WDS at TLK CECE process Solid polymer electrolyser Catalyst/packing properties will be tested for WDS design Tritiated water feed flow rate: 20 Kg/h Tritium activity in water feed: 10-100 Ci/Kg Tritiated water feed flow rate: 1.5 Kg/h Tritium activity in water feed: 1-10 Ci/Kg ISS for ITER 4 Cryogenic Distillation columns ISS at TLK 2 Cryogenic Distillation columns Packing properties (HETP and hold-up) will be tested for ITER ISS design Feed flow rate CD1: 280 mol/h Feed flow rate: 45 mol/h The influence of the return stream of CD1 ISS to WDS for further tritium depletion will be investigated, also in dynamic regimes (variable flow rates and composition) integrated tests for TRIMO validation IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 12
Effluents and releases Project guidelines for ITER tritium releases during normal operation : 1 ga -1 as HT 0.1 ga -1 as HTO A detailed release assessment has been performed for each element in the ITER WBS to ensure that no significant release pathway was missed. Estimated ITER tritium releases are: 0.18 ga -1 HT mainly from protium discharge of the Isotope Separation System (ISS) 0.05 ga -1 as HTO 0.0004 ga -1 will be waterborne, 85% out of that is due to blow down of the cooling tower 1 Contribution in the total HTO releases (%) of various subsystems Vacuum pumping Heat transfer system Fuelling Waste treatment and storage Facing Tritium plant Remote handling 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 TRIMO can be used to assess the value of releases for the FC as build in various operational scenarios IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 13
Multiple Barrier Tritium Confinement Concept at TLK Tritium Retention System PIRCA± k-kkkk Safety Valve Under Pressure Control Glove Box Tritium Infrastructure Tritium Transfer System Isotope Separation System... Primary System Secondary System Primary System Leak Rate < 10-8 mbar l s -1 Tritium compatible materials... Secondary System Leak Rate < 0.1vol % h -1... Building Wall Detritiation of all primary exhaust gases prior to discharge into the environment Detritiation systems for secondary and tertiary containments Tritium Retention System PIRCA± n-nnnn Safety Valve Under Pressure Control Glove Box Experiments Caper Petra... Primary System Secondary System Central Tritium Removal Primary Off-Gas Treatment 1. Stage (Closed Loop) Ring Manifold Provides Central Under Pressure 2. Stage (Once Through Than Out) TLK Hoods Laboratory Ventilation Stack IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 14
Primary and secondary containments Specifications for primary containments Use of tritium compatible materials Qualification of materials for work in tritium environment when this is unavoidable (Nafion membrane for the SPM electrolyser, catalysts - R&D to investigate the lifetime in the EFDA program and at TPL Japan) Definition of leak tightness Outer jacket for tritium bearing components heated to temperatures above 150 C Evacuation of the jacket interspace for thermal insulation Removal of tritium permeated through hot structural materials from the jacket protected against over-pressure, over-temperature Specifications for secondary containments (glove-boxes, hardshell boxes) provided with detritiation systems and a purge and pressure control system nitrogen atmosphere with very little oxygen (needed to convert leaked isotopic hydrogen and hydrocarbons into water and carbon dioxide) equipped with sensors to measure tritium level, temperature, pressure IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 15
PIR PIR FUSION Example of over-pressure protection: ISS Tritium monitor Process loop PIR RD AV Pump box Expansion vessel Rupture disk Relief valve Regulation valve Normal flow RV Avoiding contamination of the refrigerant with tritium (intermediate hydrogen cooling pool) Recovery of process gas after expansion following warm shutdown. In case of tritium contamination, the coldbox and the hydrogen vessel discharge the overpressure into the atmosphere detritiation system. AV RD RV ADS CD Hydrogen vessel RD AV Cold box IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 16
Integrated Atmosphere Detritiation system Configuration Tokamak Building Secondary Enclosures Secondary Enclosures Secondary Enclosures Pit Free Volume Rotary Dryer Tritium Building Containment Volume (46,000 m 3 ) Divertor Drying System During normal operation a Normal Vent Detritiation system (700 Nm3/h) processes tritiated streams In the case of an off-normal event: the HVAC systems branch ducts in each room/area are switch to the re-circulation type room atmosphere detritiation systems (S-ADS 4500m3/h). the N-VDS is backed up by the oncethrough standby vent detritiation system SVDS 3000m3/h). the S-ADS and S-VDS ensure that: Staggered negative pressure is maintained the extracted air is detritiated to the required low level before release into the environment tritium concentration in the affected room(s) is rapidly decreased. IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 17
Standby Atmosphere Detritiation System IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 18
Water Detritiation System Tritiated water will be produced in all ITER atmosphere detritiation systems (ADS) Typical tritium concentration 10Ci/kg with possibility of processing 500Ci/kg Combined Electrolysis Catalytic Exchange Process Very high detritiation factors are required to release WDS exhaust to stack R&D program to prove the capacity of WDS to further process the ISS hydrogen stream WDS is the only system in ITER that releases effluents into the environments without an additional detritiation system IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 19
Closing remarks Fuel cycle of ITER: quick recovery of tritium for recycling low tritium inventory safe handling and confinement of tritium low effluents and releases Mature technologies for all subsystems Sound modeling under validation Existing infrastructure for accompanying R&D and further developments IAEA TM on Fusion Power Plant Safety, July 10-13, 2006 Ioana R. Cristescu slide # 20