Tritium Plant in ITER and F4E Contribution. G. Piazza ITER Department, Fusion for Energy

Size: px

Start display at page:

Download "Tritium Plant in ITER and F4E Contribution. G. Piazza ITER Department, Fusion for Energy"

Silvia Wilkerson
6 years ago
Views:

1 Tritium Plant in ITER and F4E Contribution G. Piazza ITER Department, Fusion for Energy 1

2 Presentation Outline Introduction Fuel Cycle of a Fusion Reactor Overall description of the ITER Tritium Plant present status of the ITER plant and subsystems design: main technological issues and challenges of the present ITER Tritium plant design Water Detritiation System Design and R&D review of the Workplan schedule and expertise needs in the future Isotope Separation System Design and R&D review of the Workplan schedule and expertise needs in the future 2

Introduction: Fuel Cycle of a Fusion Reactor Among the potential fusion reactions technically most suitable is the reaction between deuterium and tritium Li Li 2 D + 3 T 4 He (3.5 MeV) + 1 n (14.

3 Introduction: Fuel Cycle of a Fusion Reactor Among the potential fusion reactions technically most suitable is the reaction between deuterium and tritium Li Li 2 D + 3 T 4 He (3.5 MeV) + 1 n (14.1 MeV) Be Breeding Blanket at% Deuterium are contained in natural water. Tritium Recovery TES Deuterium Supply DT Fuel Supply Plasma Blower Plasma Exhaust Vacuum Pumps He Purge Gas + Tritium from Blanket Tritium needs to be produced: 56 kg Clean-up and DT Fuel Recovery tritium is required per GWy of fusion power. Tritium Supply Tritium Plant Helium to Stack 3

4 Introduction: Fuel Cycle of a Fusion Reactor About 100 g tritium is produced per year in a standard CANDU fission unit. Breeding of tritium is necessary in a fusion reactor: n + 6 Li T + 4 He n + 7 Li T + 4 He + n In ITER, 20 to 25 kg tritium will be needed over the years (Fuel Cycle operation need ~2 kg tritium) Tritium will be imported : ~ 20 kg tritium stored in Canada, Korea 4

5 Introduction: ITER and its Fuel Cycle ITER is the next generation of fusion machine designed to operate with D-T plasma. Since fusion reactions consume only small part of injected gases, economy and safety require fuelling gases within ITER being recycled. For this purpose a number of systems allowing hydrogen isotopes retention, purification, separation and storage are foreseen to support ITER operation. In addition, a Water Detritiation system (WDS) will maintain tritium content in the exhausted protium below the limits allowed by French regulations (release limit 0.01 g/y) 5

6 ITER Buildings Nuclear Buildings Assembly hall Tokamak building Cryoplant Power supply Tritium plant building Diagnostics Hot cells Magnet power Hot basin & cooling towers Radwaste 6

ITER Machine Layout Plasma major/minor radius: 6.2/2 m Total fusion power: 500 MW Plasma current: 15 MA Toroidal field @ 6.2 m radius 5.

7 ITER Machine Layout Plasma major/minor radius: 6.2/2 m Total fusion power: 500 MW Plasma current: 15 MA Toroidal 6.2 m radius 5.3 T Fusion/auxiliary heating power: 10 Vacuum volume: ~ 1330 m 3 Plasma volume: ~ 837m 3 Plasma tritium throughput: ~ 1 kg/h Plasma tritium inventory: ~ 0.2 g Tritium site inventory: < 4 kg Fuel cycle inventory: < 2 kg M. Glugla et alii. IOverview of the ITER D-T Fuel Cycle Systems. ISFNT 11, Sept

8 The ITER DT Fuel Cycle TBD Disruption Mitigation System CN, FUND Gas Puffing CN,FUND Fuelling Gas Distribution KO, FUND Storage and Delivery External Supplies KO, FUND Tritium Depot CN, FUND US, FUND EU, FUND Glow Discharge Cleaning Pellet Injection Isotope Separation MBA 2 EU, FUND CN, FUND EU, JA, IN US, FUND Water Detritiation Torus Fusion Power Shutdown System Neutral Beam Injection Tokamak Exhaust Processing JA, FUND US, FUND EU, FUND FUND Atmosphere and Vent Detritiation Service Vacuum Systems Neutral Beam Cryo Pumps Analytical System Cryostat EU, FUND EU, FUND US FUND EU, FUND Off Gas Release Hydrogen (Protium) Release Cryostat Cryo Pumps Torus Cryo Pumps Roughing Pumps Leak Detection Tritium Plant Building FUND Automated Control System, Interlock System D. Babineau et alii. Review of the ITER Fuel Cycle. Tritium conference

9 Generic Site Tritium Plant Building Layout (ITER FDR 2001) Dimensions Length: Width: Height: 80 m 25 m 35 m Outdated design: New regulations: Escape routes not clear and too long. Airlocks not included consistently. HVAC to be changed. Increase of width and length. Stairways: 2 3 Elevator: 0 1 9

10 The Storage and Delivery System (KO) Purpose of Storage and Delivery System (SDS) To store tritium and deuterium in storage beds (70 g tritium/bed), To supply gases of the requested compositions and flow rates to the fuelling systems, 120 Pam 3 /s for 3000 s (about 1 kg DT/h), 160 Pam 3 /s for 1000 s, 200 Pam 3 /s for 400 s, To perform accountancy by in-bed calorimetry (accuracy: ~1% for fully loaded bed) and (pvt-c) measurements, To collect 3 He. 10

11 The Storage and Delivery System (KO) Safest storage technique of tritium today is the use of metal getter beds with high affinity to hydrogen. Advantages: Storage beds can act as pumps at RT and compressors at higher temperatures. Negligible tritium permeation at RT. Purity of the dissolved tritium is conserved. High storage capacity per volume. Disadvantages: needs heating to temperatures around o C Low thermal conductivity of metal hydride powder critical for achieving high hydrogen supply rates Powder is pyrophoric Creation of tritiated waste ITER changed hydride bed material from ZrCo to depleted U 11

analyses) Fast supply, Fast pumping, Accurate

12 The Storage and Delivery System (KO) ITER Getter beds still to be optimized (thermomechanical / hydraulic analyses) Fast supply, Fast pumping, Accurate accountancy, Fast cooling. Test Facility SPOVE with metal hydride bed at NFRI 12

13 The Tokamak Exhaust Processing (TEP) System (US) Purpose of TEP to treat all gases from various systems (NBI, T0rus, Cryostat, Diagnostics) to extract hydrogen from water vapour and hydrocarbons, discharge the hydrogen depleted streams via vent detritiation. Replacement of carbon by W will simplify the requirements of TEP as hydrocarbons will be no longer the dominant impurities. Main components of TEP Permeators to extract the un-burnt fuel (hydrogen) from the gas mixtures, Catalysts to crack the hydrogen containing molecules and permeators to extract the produced hydrogen, Pumps for circulation of the gases. 13

14 The Detritiation System (DS) System (JA/IO) ITER Detritiation System Block Diagram Detritiation System based on oxidation of tritium to water followed by wet scrubber columns (molecular sieve bed driers were removed) 14

dryer system required 1 column instead of 3 beds Throughput about 1500 m 3 h -1 (Ø ~ 0.

15 The Detritiation System (DS) System (JA/IO) Counter current removal by exchange of tritiated water in a wet stripping column HTO v + H 2 O l H 2 O v + HTO l No regeneration cycles as for molecular sieve beds Less complicated configuration and number of valves No dryer system required 1 column instead of 3 beds Throughput about 1500 m 3 h -1 (Ø ~ 0.7 m, L ~ 5 m) Memory effects of no great concern R&D results with tritiated water very successful (Mendeleyev University, Moscow) Pilot plant tests will be carried out in Japan (TPL) 15

16 The Water Detritiation System (WDS) (EU) Purpose of WDS Several potential sources of tritiated water exist in ITER. The largest routine contributors to the WDS feed streams are the Atmosphere and Vent Detritiation Systems. Purpose of WDS is detritiation of water (20 Ci/kg) using the CECE (Combined Electrolysis Catalytic Exchange) method via cracking water into hydrogen and oxygen, stripping the residual tritium from the hydrogen before its release. The tritium is returned to the Fuel Cycle via Isotope Separation System. Oxygen is released via Atmosphere Detritiation System Tritiated Water Holding Tanks and Emergency Tanks (2 x 100 m 3 ) store water before processing 16

Moisture separation H 2 dilution Environment O 2 processing system 20 kg/h 10 Ci/kg Front-end processing system LPCE columns

17 ITER WDS: Process Description Detritiation capacity: 20 kg/h Q 2 O (Q= any hydrogen isotope specie) increase to 60 kg/h possible in operational phase (after 2026) 4500 Nm 3 /h air Environment via Detritiation System 20 kg/h demineralized water Moisture separation H 2 dilution Environment O 2 processing system 20 kg/h 10 Ci/kg Front-end processing system LPCE columns Flame arrester ISS Q 2 O Dryer unit Membrane permeator ISS M/L M/L H L L M L H L Holding tanks Electrolyser system Q 2 O 2 Q 2 O 17

18 ITER WDS: Liquid Phase Catalytic Exchange Column schematic principle of work (LPCE) (H 2 O) L 20 kg/h (H 2 ) g 50 m 3 /h (H 2 ) g Packing (H 2 O) v (H 2 O) v + (HT) g Catalyst (H 2 O) L + (HTO) v (HTO) v (HT) g (HTO) L (H ppm T) g (HT) g ISS (HTO) L Electrolyser (HTO) L 20 kg/h, 10 Ci/kg (O 2 ) g 18

19 ITER WDS: Equipment distribution (2001 Design) O 2 gas processing: MS dryers Wet strippers Electrolyser 12 m LPCE Emergency tanks Tanks for H (>100Ci/kg), M, L (<1.6 µci/kg) level water 19

20 ITER WDS: Conceptual Design 20

21 ITER WDS: B2 level of the Tritium Plant Building Emergency Tanks (100 m 3 ) Feeding Tanks LPCE-columns Medium-Low Tritiated Water holding Tanks (20 m 3, Ci/kg) Electrolyser units High level Tritiated Water holding Tanks (5 m 3, ) 21

22 ITER WDS: Layout in the B2 level of the Tritium Plant Space allocated for the WDS on ITER Tritium Plant 22

Main Characteristics: Nuclear Vessels (non pressurised), single wall, Vacuum Test (10-5 Pam 3 /s) Tritium Concentration in water up to 300 Ci/kg) ITER WDS: Preliminary Design of Tanks SIC-2

23 Main Characteristics: Nuclear Vessels (non pressurised), single wall, Vacuum Test (10-5 Pam 3 /s) Tritium Concentration in water up to 300 Ci/kg) ITER WDS: Preliminary Design of Tanks SIC-2 components: used to prevent, detect or mitigate incidents or accidents but are not required for ITER to reach a safe state Emergency Tanks 100 m 3 (L 9.4m x D 3.8m, s=12mm) Seismic qualified (SC1-S): structural stability maintained in case of an earthquake, i.e. no rupture of piping, no collapse of structure equipment, limited plastic strain, structural support function maintained Tritiated Water Holding Tanks 20 m 3 (H 3.9m x D 3.2m, s=12mm) 23

Reference hydrogen discharge method, currently based on dilution with ambient air, has been reviewed and compared with alternative additional means of hydrogen discharge; Safety and operability of

24 Reference hydrogen discharge method, currently based on dilution with ambient air, has been reviewed and compared with alternative additional means of hydrogen discharge; Safety and operability of catalytic oxidation of H 2 with air or oxygen inside a catalytic reactor is being experimentally proven in a low-scale mock-up device. o Mixing tube 0.4 bar, 50 o C o Catalytic reactor 4 bar, 250 o C, 100 Nm 3 /h air, 2 Nm 3 /h H 2 ITER WDS: Design optimisation of H 2 discharge system 4500 m 3 /h LPCE column 24

The WDS: R&D in support of conceptual design: LPCE Example of catalyst/packing of LPCE column At Tritium Laboratory Karlsruhe (TRENTA facility), the ISS and the WDS experimental loops are operated in

LPCE column (8 m) LPCE Catalyst Packing mixtures are characterised in experimental campaigns to assess process relevant parameters: Height Equivalent of Theoretical Plate Mass transfer coefficient as

25 The WDS: R&D in support of conceptual design: LPCE Example of catalyst/packing of LPCE column At Tritium Laboratory Karlsruhe (TRENTA facility), the ISS and the WDS experimental loops are operated in stand-alone modes and in combined/integrated operation scenarios to allow full optimization of the two systems. LPCE column (8 m) LPCE Catalyst Packing mixtures are characterised in experimental campaigns to assess process relevant parameters: Height Equivalent of Theoretical Plate Mass transfer coefficient as a function of Hydrogen isotopes concentration. Presence of D 2 makes hydrogen detritiation more difficult, i.e. longer columns are needed. Water purification H 2 O HDO HTO H 2 O Stack Water purification LPCE column H 2 HD H 2 HT HD DT D 2 Permeator Electrolyser H 2 HD O 2 Stack Oxygen purification Cryogenic distillation column DT D 2 H2O 25

26 R&D on combined operation WDS-ISS Simplified schematic of WDS ISS ISS refrigerator, cold box Looking up ISS column in vacuum jacket ISS and WDS facilities at TLK-KIT Water reservoirs WDS column 26

27 Main requirements of ITER WDS electrolyser Presently 2 types of electrolysers are considered: Solid Polymer Membrane electrolyser (SPM) Liquid Alkali (KOH) electrolysers The SPM are the preferred option because There is no contamination of gaseous stream with KOH which can cause poisoning of the hydrophobic catalyst in the LPCE column and of the palladium-alloy membrane of the permeator; The water inventory is smaller than that of alkali electrolysers; There is no generation of tritiated potassium hydroxide (KOT) as a radioactive and hazardous solid waste To electrolyse 120 kg/h of tritiated water with tritium activity up to 500 Ci/kg To remove tritium from the oxygen stream down to a level that allows discharge into the environment; tentative decontamination factor of

28 Main requirements of ITER WDS electrolyser The hold-up of tritiated water to be reduced as much as technological feasible; tentative value in the range of litres. Safety requirements for hydrogen processing to be implemented (explosion risk) Free maintenance period of at least two years Leak rate for liquid containment vessels 10-5 mbar l/s Leak rate for gas containment vessels 10-9 mbar l/s Modular configuration of the electrolysis system is present reference 30 m 3 /h per module presently considered as best option Minimum throughput 10 m 3 /h per module 28

membrane; To measure the enrichment factor in the electrolyser; To estimate the tritium inventory with respect the water hold-up in the

29 R&D on PROTON electrolyser (1 m 3 /h, KIT-TLK) Main critical issues : Standard configuration of a SPM electrolyser To identify the necessary improvements for a solid polymer electrolyser to become tritium compatible (avoid plastics); To estimate the lifetime of a solid polymer membrane; To measure the enrichment factor in the electrolyser; To estimate the tritium inventory with respect the water hold-up in the electrolysis unit (minimize); Hydrogen and Oxygen Dryers Ventilation, air Purification and Hydrogen Detection SPM electrolyser for tritium service 29

R&D on PROTON electrolyser cell (KIT-TLK) Life time evaluation of a SPM electrolyser have already been performed by: Investigating the behavior of a small electrolyser cell based on a SPM over a long

30 R&D on PROTON electrolyser cell (KIT-TLK) Life time evaluation of a SPM electrolyser have already been performed by: Investigating the behavior of a small electrolyser cell based on a SPM over a long period functioning with tritiated water with tritium activity in the range of 1 Ci/kg to 100 Ci/kg Comparing mechanical properties such as tensile strength and elongation for a solid polymer membrane before and after exposure to tritiated water Results are promising: No significant differences in the performance (current) of a SPM cell operated with and without tritiated water The comparison of tensile strengths and elongation of two membranes operated with tritiated and demineralized water respectively does not show a clear impact of tritium decay for tritium in the range Ci/kg. 30

31 WDS Schedule (01/03/2012) Conc. Des. Tanks (P) R&D, Conc. Des., Prel. Des. Tanks (with Tech Specs for procurement) (G) CDR March 2011 PDR -28 Jun PA (DD) for Tanks signed Tender + Follow-up Holding Tanks Manufacture (P) Contract. sign.- Jun Contract. sign.- Jun Tender + Holding Tanks Manufacture (P) FDR - Oct Contract. sign.- Sept Contract. sign.- Sept Tender +Pr. Design (P) Delivery to ITER Large tanks ( m 3 ) Dec Tender + R&D in support of Prel. Des. (G) Tender + R&D in support of Prel. Des. (P) B2 temporary openings closed Oct Contract. sign.- Sept PA (DD) for WDS main signed Final Design, Manufacturing and Testing of components (P) FDR - Apr Completion of Delivery to ITER site Oct

32 The Isotope Separation System (ISS) (EU) Purpose of ISS To accept the hydrogen isotope mixtures from TEP, Neutral Beam Injectors and WDS. To produce the required pure deuterium (<0.02% T, <0.5% H) and 90% T/10% D gas mixtures for SDS. To transfer detritiated (<0.1 ppm T) hydrogen to WDS for further detritiation and final release. 32

33 ITER ISS: Principle of Operation Principle of operation Exploiting small differences in the vaporisation temperatures of the hydrogen isotopologues Hydrogen Isotopologues Vaporisation temperature (K) H2 HD HT D2 DT T ISS utilizes cryogenic distillation and catalytic reaction for isotope exchange to produce specific isotope mixtures. ISS comprises a cascade of four cryogenic distillation columns cooled by He (nominal operation temperature between K) and a certain number of catalytic equilibrators to modify the hydrogen molecule concentrations, thus improving the performance of the system 33

34 ITER ISS: Schematics of System To expansion volume Equilibrator (EQ) Reactions in the equilibrators HT +D 2 DT + HD 2 DT D 2 + T 2 Column (CD) 34

35 ITER ISS: status Design of ISS faces some issues ISS feed flow rate is characterized by transients due to: o Regeneration of cryo-pumps (Torus, Cryostat, NBI) impacts operation therefore modeling of ISS Fuel Cycle is needed to simulate regeneration patterns o WDS unlikely always at full capacity o Protium with traces of tritium from breeding Test Blanket Modules (flow rates not yet specified) ISS and WDS operation linked o No tritiated water feed for WDS at start of ITER operation o ISS availability linked to WDS Tritium and Hydrogen inventory is a key parameter Work has presently focussed on Review of 2001 baseline Characterisation of packing material Research of a modelling tool for the design 35

36 ITER ISS: Design Review and optimisation Following a request to modify the product/feed configuration, an H 2 O Protium Reject Protium Return H 2 (D, T) Feed ISS Column-1 assessment of ISS 2001 baseline design was launched with respect system operation and tritium inventory WDS WDS LPCE Column ISS Column-2 Eq-1 Eq-2 ISS Column-3 H 2 O (D, T) H 2 (D, T) Eq-6 Results have shown that ISS needs Electrolyzer Eq-3 D 2 (NB Injection) optimisation/ modifications to operate H 2 (T) from Neutral Beam Eq-4 with the ITER requirements D 2 (T) Product to SDS From Plasma Exhaust DT Feed Eq-7 Eq-5 DT (50 %) Product to SDS T 2 (90 %) Product to SDS ISS Column baseline design 36

ITER ISS: R&D on packing material Performance test of SULZER CY packing for the ISS cryogenic columns Experimental results indicate that liquid hydrogen hold-ups in the packing may be higher

37 ITER ISS: R&D on packing material Performance test of SULZER CY packing for the ISS cryogenic columns Experimental results indicate that liquid hydrogen hold-ups in the packing may be higher than stated in the 2001 DDD As a direct consequence, ISS design needs optimisation to avoid too high tritium inventory CY SULZER packing SS Gauze structure Diameter 50 mm Volume 5300 cm 3 37

38 ISS Schedule (01/03/2012) R&D to assess CY packing (G) Tender + R&D in support to Conceptual design (G) Tender + Conceptual design (P) Assessment of ISS 2001 Baseline (G) Tender + Preliminary Design (P) PA for ISS signed Tender + Manufacturing of ISS components (P) Completion of Delivery to ITER site Oct

39 Summary: Needs for ISS and WDS R&D in support of WDS design Development and testing of components for WDS: Catalyst/packing mixtures Electrolyser up-grade for operation with tritiated water o Components lifetime o Safety provisions for use in ITER (hydrogen explosion, fire, release of Tritium in form of tritiated gas or water) R&D in support of ISS design Development of modelling tool for ISS design Development and testing of components for ISS: Packing Combined operation WDS-ISS 39

40 Summary: Needs for ISS and WDS Design Preliminary Design of systems in terms of processes, mechanical design, electrical, control and instrumentation, Development of feasibility, reliability, availability, mantenability, inspectability and safety provisions for use in ITER (hydrogen explosion, fire, release of Tritium in form of tritiated gas or water) Preparation of guideline documentation required for building, testing, operation and maintenance of tritium handling systems Final Design (competencies as above but going to a deeper level of details) Manufacturing Manufacturing of WDS and ISS equipments Follow-up of manufacturing and testing/commissioning activities (Integrator Role) Support to ITER IO in assembling final components 40

41 Summary: Needs for ISS and WDS Needed expertise: Design of Chemical plants, Nuclear facilities, cryogenic facilities Manufacturing of components for Chemical plants, Nuclear facilities, cryogenic facilities Management of large project in international environment and with very stringent requirements and quality control. 41

42 42

Tritium Inventories and Containment Philosophy for the Fuel cycle of ITER

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,