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Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007) 11-12 June 2007, Idaho Falls, ID, USA. Recent and on-going tritium-related activities in the EU for helium-cooled lithium-lead blanket. M. Zmitko, G. Dell’Orco, R. L ässer, Y. Poitevin
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Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007) 11-12 June 2007, Idaho Falls, ID, USA Recent and on-going tritium-related activities in the EU for helium-cooled lithium-lead blanket M. Zmitko, G. Dell’Orco, R. Lässer, Y. Poitevin EFDA CSU Garching Presented by M. Zmitko Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Helium Cooled Lithium Lead (HCLL) Breeder Blanket HCLL Breeder Blanket for DEMO HCLL Test Blanket Module to be installed in ITER Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
The liquid PbLi (breeder material) flow The liquid PbLi is slowly flowing (10-30 recirculations/day) for tritium removal outside the TBM (dedicated extraction system in the PbLi loop) Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Presentation outline Tritium related R&D activities in the EU • Tritium interaction with PbLi and transfer kinetics: • Solubility, diffusivity measurements • H isotopes partial pressure measurement in PbLi • Technology and components experimental testing using dedicated test facilities: • TRIEX for study of tritium extraction from liquid Pb-Li • EBBTF for HCLL mock-ups and prototypes testing • LM loop for components (cold traps) testing • Development and qualification of anti-permeation coatings • Objectives and requirements • Current R&D program • Development of Tritium-related ancillary systems for HCLL TBM: • TES – Tritium Extraction System • TRPS – Tritium Recovery from Purge Gas • CPS – Coolant Purification System • Modelling of tritium transport and behaviour, tritium cycle modelling • Future activities Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Tritium interaction with PbLi and transfer kinetics: Solubility, diffusivity and measurements of hydrogen isotopes in PbLi Associations: CIEMAT, ENEA, Pol. di Torino Main objectives: • Solve the discrepancies among available experimental data on Sieverts’ constant and diffusivity values for Tritium in Pb-Li using both desorption and adsorption experimental techniques; • Development and optimization of sensors for hydrogen isotopes partial pressure measurement in PbLi: • Optimization of design of conventional H sensors (pure iron permeable capsule) • Development of innovative bi-layer H sensor (porous alumina coated by thin metallic Pd-Ag). Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
ENEA - EURATOM H transfer kinetics in Pb-Li Solubility (Sieverts’ constant) vs. temperature (SOLE apparatus) 5x103 – 1.5x105 Pa Diffusivity vs. temperature (LEDI apparatus) 5x103 – 1.5x105 Pa Reiter‘s data Sievert’s constant determined in SOLE (obtained with adsorption techniques) is about 1.5 orders of magnitude higher than Reiter’s values obtained by desorption technique. Diffusivity determined in LEDI is about 2 orders of magnitude higher than Reiter’s values. The obtained data are probably influenced by parasitic phenomena (liquid convection and/or gas coalescence). Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
UPV–EHU/CIEMAT Experimental determination of Sievert’s constant and diffusivities values for tritium in PbLi using absorption & desorption techniques PREPARATION OF ABSORPTION – DESORPTION FACILITY • Foreseen experimental conditions: • 250-650°C • 103 – 105 Pa hydrogen loading pressure • material of exp. chamber: Pyrex glass and quartz • PbLi in W container Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Optimized sensors for H partial pressure measurement in PbLi • Design optimization of pure iron sensors: • i) Annular geometry with reduced thickness of wall (no He tightness); • ii) Cylindrical capsule with reduced wall thickness; relatively high time response (2 hours). • Materials of sensor permeable capsule: • i) Nb: not suitable due to oxidation and lowering of H permeations vs. time; • ii) Pure Fe (ARMCO 99.5%): successfully welded and tested both in gas and PbLi phase. Optimized Fe (ARMCO 99.5%) cylindrical capsule • Thickness of the permeable walls: 0.125 mm; • Manufacturing: welded with a laser technique; • Filler: cylinder of Al coated with Au; • He tightness OK. Experimental tests on cylindrical sensor in gas phase at T = 400 - 500 °C, p 10-100 mbar Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Innovative permeable bi-layer sensors for H partial pressure measurement in PbLi New permeable capsule has been designed to improve the dynamic performance using a thick sensor membrane made in porous Alumina (with high hydrogen permeability and low affinity with oxygen) coated, via magnetron sputtering technique, by 2 mm Pd or Pd-Ag layer and brazed to the EUROFER capsule. Porous Alumina in PbLi at 400°C, 120 h Porous Alumina coated by Pd/PdAg on gas side PbLi layer The porous Alumina is a support while the thin metallic Pd/PdAg coating acts as a material selective among H isotopes. Porous Alumina in PbLi at 500°C-800 h Compatibility tests between porous Alumina and the Pb-Li carried-out at 400-500°C up to 800 h. Neither microstructural modification nor infiltration of molten alloy in the porous Alumina have been observed. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Technology and components experimental testing using dedicated test facilitiesAssociations: ENEA, IPP-CR • Main objectives: • TRIEX (ENEA): • check of performances of the most promising H extraction system from Pb-Liby gas-liquid contactors (packed columns) vs. PbLi mass flow rate and Ar stripping gas volumetric flow rate; • change of H extractor geometry and the filler/packing columns; • reaching of extractionefficiency > 30%; • future tests on other extraction techniques as V-based getters and different permeators. • EBBTF (ENEA): PbLi loop, ancillary of existing HeFus3 facility, for out-of-pile testing of HCPB/HCLL TBM mock-ups and prototypes at ITER relevant conditions. • LM Loop (IPP-CR): PbLifacility to test various components of HCLL TBM auxiliary system (e.g. a cold trap, high temperature flanges, pump) at temperatures of 260-550°C and PbLivelocity of 5-30 mm/s. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
ENEA - EURATOM TRIEX loop for study of hydrogen (tritium) extraction from liquid Pb-Li Main operation parameters: Liquid metal flow-rate rate : 0.2 – 0.5 kg/s PbLi inventory: 120 l (80 l in circulation tank) H-extractor temperature range:350-500°C H2partial pressure in Pb-Li : 200-6500 Pa Stripping gas: Argon Stripping gas flow-rate: 5-150 Nl/h The first experimental test campaign on TRIEX loop is in progress at ENEA Brasimone with the objective select the most promising hydrogen (tritium) extraction method from liquid Pb-Li(e.g. packed columns). Extraction column filler Test matrix for first phase of TRIEX experiments S2– H saturator S3– extraction column S1 – circulation tank S1 – circulation tank; S2 – H saturator; S3 – extraction column; EFT – electromagnetic flowmeter; HLM – hydrogen sensor in Pb-Li; G – getters; H2G – hydrogen sensor in gas. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
NRI/IPP - CR LM loop for components (cold traps,…) testing Development and testing of various components for HCLL TBM auxiliary system (e.g. a cold trap, high temperature flanges, pump). Demonstration of the components feasibility (pump, flanges) and efficiency (cold trap) using dedicated Pb-Li loop. Testing parameters: temperatures of 260-550°C and flow velocity of 5-30 mm/s. Tank Pump Corrosion test section Cold trap Sampling • Investigations of the cold trap purification efficiency of removing typical corrosion products (CPs) and impurities from Pb-Li liquid metal.Cold traps: wire mesh, rings,… • Model experiments will be performed with two eutectic compositions: (i) with higher content of CP containing Fe, Cr, Mn, (ii)with certain content of Bi as main element of impurities.Pure metals Fe, Cr and Mn will be added to the eutectic during the Pb-Li heat preparation. Bi will be dosed directly into the testing facility by the special dosing equipment.CP and impurities concentrationsbefore and after the cold trap will be analyzed using ICP-MS technique. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Development and qualification of Tritium anti-permeation coatings Associations: CEA, FZK, IPP-Garching, CRPP,ENEA,NRG, IPP-CR Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Background Anti-permeation coatings: • Tritium permeation from the Pb-Li liquid metal alloy into the He coolant and finally into the environment is one of the most critical issue for DEMO blanket. • The control and reduction of tritium releases can be achieved using a suitable tritium permeation barrier (TPB). • Since alumina has the capability of tritium permeation reduction, the development of Al-based anti-permeation coatings has been selected as one of the promising directions in the EU R&D program. Other routes are based on development of erbium oxide (Er2O3) anti-permeation coating. Moreover, it has been also demonstrated that natural oxides formed on the structural material surfaces (e.g. EUROFER) can serve under certain conditions as a TPB. • W-based anti-corrosion coatings, being developed to reduce or even suppress the corrosion process and to improve structural material corrosion resistance at critical locations of the breeder blanket, could in principle also act as anti-permeation coating . Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
The main requirements for the anti-permeation and anti-corrosion coatings • Chemical stability/compatibility with the adjacent environment (Pb-Li, He with H2/H2O and possibly other gas additions) up to the maximum operation temperatures (approx. 550°C), • Mechanical integrity: • High crack resistance upon thermal cycles, • Thermal expansion of the coating and of the substrate (EUROFER) should be very similar, • High irradiation resistance, • High Permeation Reduction Factor (PRF) (valid for anti-permeation coatings), • Safety/environmental characteristics, e.g. low activation in fusion spectra, • Potential for production of coatings on complex internal or/and external geometrical configurations, • Potential for in-situ self-healing of any defects in the coatings that might occur. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
R&D Programme Objectives • The main objectives of the EU R&D programme in the direction of the coatings is development and qualification of suitable anti-permeation and anti-corrosion coatings and coating techniques in order to be used in the HCLL breeder blanket concept. • The coating/deposition technologies aiming at achieving required quality, reproducibility and PRF (in the range of >10-50), and taking into account geometry constraints of breeder blanket components. • It is considered that such coatings & reference coating technologies for DEMO could be tested at later stage of ITER operation (possibly before the end of the first 10 years of ITER operation) by means of the respective HCLL Test Blanket Module (TBM). Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
R&D program on the coatings • Development of Al2O3-based and Er2O3-based anti-permeation coatings: • Electro-chemical (galvanic) deposition of Al with subsequent heat treatment to optimize the coatings composition and morphology, • Physical vapour deposition (PVD) process using plasma arc discharge method (possibility to produce dense, crystalline -Al2O3 and Er2O3 coatings of 0.5-1µm in thickness), • Chemical vapour deposition (CVD) process, • Application of the pulsed electron beam technique for deposition of Al-based coating • Development of W-based anti-corrosion coatings: • Application of plasma spraying techniques, in particular Laser Assisted Atmospheric Plasma Spraying (LAAPS) process, • Screen Printing with Laser Remelting process, • Electro-chemical (galvanic) deposition, • Physical vapour deposition (PVD) process, • Development of ‘sandwich’ coatings of Er2O3 or Al2O3 with W to be used as a combined anti-permeation and anti-corrosion barrier, • Development of suitable natural oxides, serving as the TPB, on EUROFER and/or Inconel/Incoloy surfaces by optimization of H2 and H2O addition in the He coolant, • Ongoing R&D on investigation of natural oxide permeation behaviour under neutron irradiation (LIBRETTO experiments), • Characterization of the developed coatings in terms of morphology, metallographic characterization, density, chemical and phase composition, adhesion to the substrate, etc. • Qualification of the developed coatings in terms of compatibility with flowing Pb-Li, corrosion resistance, thermo-mechanical stability, protium/deuterium permeation characteristics, irradiation performance, activation and decay behaviour in fusion spectra Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Development and testing of anti-permeation coating Hot-Dip aluminizing process (HDA) Parameters for hot dipping: 700°C, dipping time 30 s Measurement of Permeability of HDA-coated tubes in H2-gas and Pb-17Li Microstructure of hot dipped surface solidified Al Fe2Al5 HV 1000 230 PRF 15 10% Cr steel The alloyed surface layer consists of brittle Fe2Al5, covered by solidified Al Microstructure after heat treatment HV 320 270 240 FeAl ENEA-Brasimone -Fe(Al) Heat treatment at 1040°C/0.5 h + 750°C/1 h and an applied pressure of >250 bar (HIPing) reduces porosity and transforms the brittle Fe2Al5-phase into the more ductile phases FeAland -Fe(Al) 10% Cr steel FZK Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Thin Erbia and Alumina Coatings Development • IPP Garching activity – Filtered vacuum arc device (PVD) • Coatings deposited and tested as anti-permeation barriers: • thin α-Al2O3 coating on EUROFER • thin Er2O3 coating on EUROFER • thin sandwich coating W-Al2O3-EUROFER EUROFER with 0.5 µm Er2O3 coating (D. Levchuk, 2005) Permeation characteristics of Al2O3 and Er2O3 coatings Permeation characteristics of W-Al2O3 sandwich coatings IPP-Garching Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
PS-W-500 SEM micrograph of a corroded sample and XDS line profile. Coatings development and testing Development Al-based anti-permeation coating by electro-chemical (galvanic) technique Development and testing of W anti-corrosion coatings to improve the corrosion resistance of EUROFER in Pb-17Li at 550°C CRPP W layer PS FZK Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
ENEA - EURATOM Testing of natural oxides on EUROFER acting as a TPB • EUROFER reference value 5.7E-11 (Aiello et al.) Effect of H2/H2O ratio on permeability and PRF; Testing at 550 C using deuterium 75/3 110/3 Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Tritium behaviour / permeation under irradiation conditions • An irradiation campaign is ongoing in NRG Petten to address tritium behaviour and permeation under irradiation – LIBRETTO 4/1, 4/2 irradiations • Objectives of the LIBRETTO irradiation programme: • Irradiation at 350 and 550°C • Tritium permeation/release measurement of bare EUROFER • In-situ oxidation (He saturated with water vapour) of EUROFER outer part • Tritium permeation/release measurement of oxidized EUROFER • Estimation of PRF caused by natural oxide on EUROFER EUROFER LIBRETTO rig design FOM-NRG Fe2O3/Cr2O3 layer SEM picture of Eurofer material oxidized for 1000 hours LIBRETTO 4/2 Irradiated at 350°C Bare EUROFER Tritium permeation 16% T permeation before and after EUROFER oxidation; deterioration after 3 days of irradiation LIBRETTO 4/1 Irradiated at 550°C Bare EUROFER Tritium permeation 25% Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Development of Tritium-related ancillary systems for HCLL TBMAssociations: CEA, ENEA, FZK • On-going development: • TES - Due to low tritium generation (8.79E-7 g/s) in TBM, the TES Tritium extraction efficiency could be relaxed to around ~30%. Therefore, gas-liquid contactors (i.e packed columns) with optimum PbLi/He stripping gas ratio (+ H2) (result from TRIEX tests) are, at present, considered; • TRPS - Removal of impurities by an adsorbent type cartridge filter and Q2 extraction by the TSA adsorption beds; • CPS - Tritium and impurity removal by a three step process: i) oxidation of Q2 and CO to Q2O and CO2; ii) removal of Q2O by a first PTSA (“Q2O-PTSA”); iii) removal of impurities by a second PTSA (“IMP-PTSA”). Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
ENEA - EURATOM TRPS Tritium Recovery from Purge Gas for HCLL TBM Tritium recovery and impurity removal by a two step process: • removal of impurities by a adsorbent cartridge filters; • recovery of Q2 by a TSA adsorption beds at LN temperature (78 K). • Possible allocation in Port Cell (if space available) or in a single glove-box in the ITER tritium plant - Size LxWxH 3.0x1.5x2.6 m3. Recovery of Q2 by a TSA adsorption beds at LN temp. Removal of impurities by a cartridge filters Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
ENEA - EURATOM CPS - Coolant Purification System for HCLL TBM Tritium and impurity removal by a three step process: i) oxidation of Q2 and CO to Q2O and CO2 at 553 K; ii) removal of Q2O by a first PTSA (“Q2O-PTSA”) at 298/573 K; iii) removal of impurities by a second PTSA (“IMP-PTSA”) at 78/373 K; iv) allocation in TCWS vault - Size LxWxH 5.0x2.2x2.8 m3. Removal of Q2O by a first PTSA (“Q2O-PTSA”) Oxidation of Q2/CO to Q2O and CO2; Removal of impurities by a second PTSA (“IMP-PTSA”) Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Modelling of tritium transport and behaviourAssociations: CIEMAT, CEA, ENEA Main objectives: • Modelling of the EU breeder blankets Tritium cycles • Development of a Computing Tool for DEMO and TBM blankets tritium cycle (ongoing activity; COMPU task – TRICICLO code) • Determination of ranges for tritium inventories in PbLi and He cooling circuits of the HCLL TBM • Modelling of Tritium permeation towards the HCS in the Breeder Units taking into account MHD effect and T diffusivity • Sensitivity effect of Pb-Li velocity profile in various locations of the breeder blanket structure on T permeation (ongoing activity) • Assessment of He bubble phenomena in Pb-Li • He nanobubbles formation and accumulation, and the potential impact on tritium transport behaviour (ongoing activity); He nanobubbles formation theoretically predicted; up to approx. 25% of generated tritium could be stripped into bubbles Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Modelling of the EU breeder blankets Tritium cycles • The main objective is to develop a computing tool capable of providing an overall quantitative evaluation of the tritium paths from the breeding materials into other systems, i.e. HCS, TES, CPS and the environment. • Analyses mainly focused on the HCLL and HCPB DEMO blankets, but preliminary indications for the ITER TBM shall be given. TRICICLO code developed. • Determination of the environmental tritium release from the HCS loop through the SGs should result in determination of the allowable HT partial pressure in He coolant at the inlet of the SGs. DEMO HCLL TRICICLO lay-out TRICICLO: MathCad 12 routines/modules with VisSim5.0H tool interface CIEMAT Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Future activities – external conditions • New organization of TBM-related activities in the EU • Establishment of the European Joint Undertaking for ITER and the Development of Fusion Energy named ‘Fusion for Energy’ acting as Domestic Agency for ITER (June 28, 2007); fully operative at the end of 2007 or beginning of 2008 • TBM-related activities (TBM is considered as a Project) will be managed and coordinated by the ‘Fusion for Energy’ that will act as a Project Owner; it will be also responsible for an international collaboration. • Establishment of Consortium of Associates that will act as a Project Contractor with the main objectives to develop, produce, qualify, install and operate the European TBM Systems in ITER Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Future activities – possibilities for collaboration (1) Future HCLL TBM tritium & PbLi-related R&D and development activities: • Tritium – PbLi interaction: • Tritium solubility in PbLi, e.g.: • experimental determination of Sievert’s constant (on-going activity (103-105 Pa), data and assessment still pending), • verification of validity of the Sievert’s law at low T partial pressure 10-2 – 102 Pa • Tritium transport in PbLi, e.g.: • experimental determination of diffusivity (on-going activity, data and assessment still pending), • Helium solubility in PbLi, clarification of the effect of He bubbles in liquid PbLi and their influence on tritium transport, • Update PbLi properties database • Tritium permeation through structure materials: • A lot of experimental data exists, but • A general mass transport model allowing prediction of tritium permeation rate is still missing (e.g. validity of the Sievert’s law for tritium-steel system at low T p.p., effect of surface parameters for slightly oxidized steel, isotope swamping effect,…) • In more general: modelling and verification of tritium behaviour in TBM and relevant ancillary systems; development and validation of a Tritium cyclesystem code; determination of the most effective ways for tritium control. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls
Future activities – possibilities for collaboration (2) • Future HCLL TBM tritium & PbLi-related R&D and development activities: • Development of instrumentation for PbLi application: • Q2 sensor for low partial pressures • Flow meters for low flow velocities • Thermocouples compatible with PbLi • Further development, testing and qualification of anti-permeation coatings. • Further design and experimental activities on development and qualification of TBM-related components and ancillary systems TES (additional TRIEX experimental campaigns), TRPS and CPS. Development of suitable means for tritium accountancy. • Development of technology procedure for PbLi enrichment in Li-6, non-proliferation issues, handling and transport rules. • Neutronic analysis of Pb-Li eutectic alloy in fusion relevant neutron spectra related to the formation of transmutation products (e.g. Bi, Po, Hg, Tl). Set-up of the impurities limits. Meeting on R&D for Tritium & Safety Issues in PbLi Breeders, 11-12 June 2007, Idaho Falls