Status of the HCLL and HCPB Test Blanket System instrumentation development

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1 Status of the HCLL and HCPB Test Blanket System instrumentation development Pattrick Calderoni The European Joint Undertaking for ITER and the Development of Fusion Energy ('Fusion for Energy' ) ITER Department TBM Group (On leave from Idaho National Laboratory, Fusion Safety Program) 21st Topical Meeting on the Technology of Fusion Energy (TOFE) 9-13 November 2014, Anaheim, CA 1

2 WHAT IS F4E? The European Union organisation for the development of fusion energy European public organization set up in 2007 for 35 years 29 member states (EU28 + CH) Headquarters: Offices: Barcelona, Spain Cadarache, France Garching, Germany Members of staff: 400+ (mostly engineers and scientists) Budget: 6.6 billion EUR (2008 value) : almost 6 billion current EUR for fusion procurements (mainly ITER)

3 OUTLINE HCLL and HCPB Test Blanket System Sub-systems control instrumentation TBM instrumentation 3

4 Fusion blanket concepts selected for the ITER TBM program Blanket type WCLL HCLL HCPB WCCB LLCB DCLL Molten Salt Li-V HCCB SCLL Li Evap. Structural material Breeder Neutron Multiplier Coolant RAFM RAFM RAFM RAFM RAFM Pb-16Li (liquid) H 2 O (15 MPa) Pb-16Li (Liquid) He (8 MPa) Li 4 SiO 4, Li 2 TiO 3 (pebbles) Be (pebbles) He (8 MPa) Li 2 TiO 3 (pebbles) Be (pebbles) Supercritical H 2 O (25 MPa) Pb-16Li (liquid) + Li 2 TiO 3 (pebbles) He (8 MPa) T coolant T Structural material RAFM + ODS Pb-16Li (liquid) He (8 MPa) + Pb-16Li (He) (PbLi) Ferritic Steel FLiBe (liquid) Be (pebbles) FLiBe (liquid) V alloy (+ insulation) Li (nat.) Li (nat.) SiCf/SiC SiCf/SiC W alloy Li 2 TiO 3, Li 2 O (pebbles) Be (pebbles) He (10 MPa) Pb-16Li (liquid) Pb-16Li Li (nat.) Li (nat.) evap max max TBM Leaders First 10 years of ITER operation Potentially tested in second phase of ITER op. 4

5 Test Blanket Modules (TBM) for testing in ITER ~1,6 m Helium-Cooled Pebble-Bed Helium-Cooled Ceramic Breeder Helium-Cooled Ceramic Reflector Water-Cooled Ceramic Breeder Helium-Cooled Lead-Lithium Lead-Lithium Ceramic-Breeder 5

6 The HCLL and HCPB TBM Systems (TBS) 2 Tritium Extraction/ Recovery Systems (Tritium Building) 2 Helium Cooling Systems 2 Helium Purification Systems (CVCS Area) Helium-Cooled Lithium-Lead (HCLL) TBM 1 Ancillary Equipment Unit and connection pipes (Port Cell) Helium-Cooled Pebble-Bed (HCPB) TBM 2 TBMs and their Radiation Shield (Port Extension) 6

7 PSCC 7

8 OUTLINE HCLL and HCPB Test Blanket System Sub-systems control instrumentation TBM instrumentation 8

9 Sub-systems control instrumentation Temperature Reference technology is type K thermocouples in metallic sheets (thermo-wells) welded perpendicularly to the system pipes between a third and half pipe diameter (common to ITER diagnostics development (PBS-55 G2). For conventional sensors head mounted voltage to current converters are considered for higher accuracy, but qualification for Port Cell 16 conditions (radiation, EM noise) is on-going as part of development activities. Heating elements not yet considered in the analysis. 9

10 Sub-systems control instrumentation Siemens differential pressure sensor for 8 Mpa helium (HELOKA) Pressure measured by diaphragm pressure transmitter. Reference COTS sensors are based on a metallic diaphragm deflected by a fill fluid with embedded resistors where a signal is amplified and digitized by signal conditioning electronics in semiconductor-type packages. In alternative dry capacitance sensor the deflection itself of the process isolating diaphragm (ceramic or metallic) is directly measured (common to ITER diagnostics development (PBS-55 G3)). All safety sensors are in contact with inert gas and mounted on pressure taps (welded capillary lines) for temperature control. For measurement of the hydraulic pressure of Pb-16Li the pressure taps are filled with an incompressible intermediate liquid - reference from Pb-Bi systems, eutectic sodium-potassium molten salt (Na- 22K). Design optimization and experimental planned as part of development activities. Robert Stieglitz, Handbook on Lead-bismuth Eutectic Alloy, 2007 edition, Chapter 11, Instrumentation 10

11 Sub-systems control instrumentation Coriolis mass flow meter operating principle involves inducing a vibration of the flow tube through which the fluid passes, which provides the rotating reference frame which gives rise to the Coriolis effect. Sensors monitor changes in frequency, phase shift, and amplitude of the vibrating flow tubes and relates to mass flow rate and density of the fluid. Flow rate Reference technology for conventional sensors for helium and Pb-16Li is Coriolis flow meter. Back-up alternative: Differential Pressure flow meters or the related Vortex flow meter for high flow rate helium systems. For reliability simple primary elements are considered as reference (conditioning orifice plate and V-cone). Feasibility and optimization for Pb-16Li is part of development activities. Main advantages: measure mass flow directly, independent of operating temperature, pressure, or composition not affected by EM noise. 11

12 Sub-systems control instrumentation Liquid metal level Radar level sensor technology is selected as reference option. The sensor emits a microwave signal and monitors its reflection from the liquid metal surface. The distance is determined based on the time of flight. Sensitivity and measurement range depend on the shape of antenna but the sensor response is not affected by dust or condensation. COTS sensors are available and experimental validation is planned as part of development activities. Vegaflex 66 probes 12

13 Sub-systems control instrumentation Other sensors are related to the measurement and control of the concentration of H isotopes and impurities in fluid streams (in addition to TAS). Tritium concentration in Pb-16Li H2 and impurities concentration in CPS: reference design based on mass spectrometer coupled with infrared spectroscopy. An alternative is a system based on a gas chromatography coupled with a humidity sensor. Both options are being tested as part of development activities. Control of H2 concentration in helium purge streams (TRS and TES): reference design based on COTS components, flow meters and controllers (for helium and hydrogen) and hydrogen meters based on thermal conductivity detector (TCD) technology. Control of cover gas in PbLi loop: reference design based on COTS components, flow meters and controllers. Gamma ray detectors embedded in the PbLi loop storage tank and cold trap. Additional instrumentation deployed to control and monitor the performance of specific components not identified at this stage of design, for example heating systems and getter bed vessels. Chemical analysis of the liquid metal are limited to PIE activities. Feasibility of periodic sampling in the CT by-pass leg coupled with a compact chemical analysis system is under consideration for the next phase of design. Note: The monitoring of environmental conditions in PC16 related to radioactive inventories (tritium, including room air and surface concentration monitoring and neutron induced) is outside of the scope of TBS instrumentation because its development and procurement belongs to the operator responsibilities (IO). 13

14 Tritium Accountancy Station TAS is responsible for compliance to ITER requirements with PBS32 (Tritium Plant) The design of TAS is driven by its two main functions: Accountancy, by measuring the amount of tritium that in a given period of time enters the Tritium Plant - an administrative service of basic importance for the nuclear operator. Discrimination: through the independent measurement of the tritium amount collected at the end of each TBS sub-system (including isotopic composition when relevant) provides data towards the fulfillment of the TBM project scientific mission. In particular, allows the validation of modeling tools to predict the amount of tritium generated in the TBMs and its transport along the TBS sub-systems. Components of the secondary barrier (in particular, the Glove Box hosting the system in the Tritium Process Room) are common between HCLL and HCPB TBS. TAS is considered an independent sub-system of the I&C. 14

15 Neutron Activation System HCPB TBM set PC16 The TBM NAS measures the absolute neutron fluence and the absolute neutron flux with information on the neutron spectrum in selected positions of the TBM. Tritium building Working principle: The system moves small activation probes (capsules) in TBM irradiation ends by pneumatic transport with pressurized helium; Capsules are irradiated for a selected period, depending on their materials composition (several tens of seconds up to the full plasma pulse length); Capsules are extracted and transported to a gamma spectrometer that measures the induced gamma activity from which the neutron flux and neutron fluence is calculated; after the measurement the capsule is sent either to a disposal or storage (for later measurement). 15

16 Neutron Activation System The design is leveraging synergies with the development of a similar system for ITER diagnostics (PBS-55 B8) The design of the capsule, the activation foils composition and the counting station is part of on-gong development activities focused on the selection of short-living induced gamma activity materials for measurements cycles in the order of 30 seconds (10 s irradiation, 20s cooling during transfer) for time-dependent measurements of n parameters; Established materials used for standard dosimetry in fission systems with long measurement cycles (1000 s irradiation, 1000s cooling) also foreseen; 3 irradiation ends have been considered for each TBM set for design integration, each routed in one of the instrumentation pipes. 6-8 mm 15 mm Integration in HCPB BU Integration in HCLL BU NAS pipe layout between HCLL TBM and shield 16

17 OUTLINE HCLL and HCPB Test Blanket System Sub-systems control instrumentation TBM instrumentation 17

18 TBM instrumentation The development of TBM sensors is the subject of ongoing research activities and a comprehensive design update is expected only as part of design consolidation. The minimum set of sensors installed on all the types of TBMs (basic instrumentation) identified in previous analysis is considered as reference for design integration and the development of the test plan, where additional instrumentation is considered for each TBM type for the fulfillment of the project scientific mission. HCLL TBM basic instrumentation HCPB TBM additional basic instrumentation 18

19 TBM box sensors integration 3 types of mounting: External Hollow stiffening rods (BU) Manifold pipes Note: Proposed solutions are preliminary. Integration aspects related to assembly and fabrication procedures (ie, weld heat treatment) will be considered for further development. 19

20 TBM box sensors integration All sensor cables are routed thru 3 instrumentation sleeves in the TBM shield, pipe forest and PC16 up the marshaling boxes of PSCC 20

21 Temperature mapping K-type Tc bonded to the Eurofer structure or inside grooves (external sensors) are technically feasible but the number proposed to map TBM operation (112 for HCLL TBM) and their design requirements (ie, EM shielding) is not compatible with integration of sensors and cables in TBS. Combine limited number of Tc with distributed Optical Fiber Sensors (OFS) to measure temperature at multiple locations of a single fiber. OFS are immune from EM noise and other electrical issues, such as grounding and isolation requirements. Distributed measurement by Fiber Bragg Grating (FBG): patterns inscribed in small sections of the fiber core with varying refractive index. Core material is pure silicon or sapphire for high temperature application and the grating is inscribed using femtosecond Infrared (IR) lasers. 21

22 Temperature mapping Operating principle: a narrow spectral component at the Bragg wavelength is reflected by the grid. A linear shift in the reflected wavelength is induced by strain and temperature. 2 fibers (one bonded) are used to decouple strain Δλ B λ B = 1 ρ e ϵ + (α Λ + α n )ΔT δλ δδ α Λ = 1 and α Λ δδ n = 1 n δδ ϵ = strain; T = temperature ρ e = strain optic coefficient α Λ = thermal expansion coefficient α n = thermo optic coefficient Validation at TBM temperature Performance under irradiation? 22

23 Strain in TBM/shield attachments Strain sensors embedded in thin plates for TBM global force reconstruction based on the structure modal analysis Pending OFS technology qualification for TBM COTS sensors based on piezoelectric technology are the alternative (similar integration issues as Tc) 23

24 EM-TBM instrumentation Electro-Magnetic (EM) TBM (plasma H-He phase) main objectives with relevance to instrumentation: Validation of the capability of heat extraction from the first wall; Validation of the structural integrity of the box and the response of the mechanical attachment; Validation of the effect of magneto-hydrodynamic (MHD) phenomena on the TBM performance and the operation of the PbLi loop (HCLL); Verification technologies and design solution of sub-system components not related to tritium. Magnetic field measurements (external) - common to PBS 16/17 Under development: Measure induced current distribution in TBM structures by potential probes in order to validate the EM models predictions; Measure temperature and electric potential with miniaturized probes in contact with flowing Pb-16Li to map the electric potential (MHD predictive models validation). Hall sensors JET-like MICs for ITER in-vessel application: (i) low-riemf/tiemf materials (ii) Reduced radiation heating thermal gradients 24

25 NT-TBM instrumentation Neutronic (NT) TBM (plasma D and short-pulse DT phases) main objectives with relevance to instrumentation: NAS Verify the operation and calibrate neutron sensors; Preliminary validation of the TBM neutronic response, including tritium production rate (TPR); Verify the operation and calibrate instrumentation and systems dedicated to the measurement and control of tritium in the sub-systems (including TAS). Priority for D plasma op: Can discriminate neutron energy (spectra) Can be optimized to measure low flux/fluence 6 LiF-diamond (SiC) detectors Under development: Modified SCD and other Li-based sensor technology for TPR; main challenge is high temperature op Self-powered neutron detectors Validate in pulse DT plasma op: Low technological maturity potential for high sensitivity Emitter: V, Co, Rh, Ag, Au, Pt 25

26 TT-TBM instrumentation Thermo-mechanic and Tritium control (TT) TBM (DT phase) main objectives with relevance to instrumentation: Verify the operation and calibrate micro-fission chambers (MFC); Validate the TBM neutronic response; Validate the thermo-mechanical response of the TBM box under DEMO relevant loads, including volumetric heat deposition; Validate the thermo-mechanical response of lithium ceramic and beryllium pebble beds under DEMO relevant loads, including volumetric heat deposition (HCPB); Verify the operation and calibrate instrumentation for functional materials analysis (PIE). Fission micro chambers 26

27 IN-TBM instrumentation The Integral (IN) TBM (DT phase) main objectives with relevance to instrumentation: Validate tritium control and recovery in the HCLL and HCPB breeding blanket; Continue the validation of the thermo mechanical response of the TBM box under DEMO relevant loads and extend the reliability and operational performance database for materials and components (up to 3 dpa); Validate technologies and design solution of sub-system components and extend the reliability and operational performance database ; Validate the performance of HCPB functional materials (lithium ceramics, beryllium and possibly, permeation barriers) by characterizing their state (mechanical integrity, surface condition, mechanical properties, etc) during PIE activities, including the assessment of activation and the compatibility with Eurofer97; Validate Pb-16Li chemistry control and corrosion of structural materials in the HCLL TBM and PbLi loop by measuring title, composition and impurities of samples during PIE activities. IN-TBM sensors should maximize reliability minimize intrusiveness OFS to measure temperature and strain in addition to the basic TBM box instrumentation are considered pending the assessment of their stability under irradiation Neutronic sensors are necessary to quantify source term all sensors are considered at this stage, pending results of performance validation and design integration studies 27

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