what can be measured in, what eu iter tbm systems · 2016. 5. 5. · what can be measured in, what...

What can be measured in,What can be learned fromEU ITER TBM Systems

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Y. Poitevin (F4E), A. Ibarra (CIEMAT),with contribution from F4E/TBM project team

and the TBM Consortium of Associates

3rd IAEA DEMO Programme WorkshopASIPP (China), 11‐15 May, 2015

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Table of contents

1. Two European TBM Systems in ITER2. Mission and Objectives of the European TBM Program3. Expected Return on Experience4. Implementation in ITER:

a. MHD experimentsb. Neutronics experimentsc. Tritium experimentsd. EM experiments

3rd IAEA DEMO Programme Workshop, 11‐15 May 2015, ASIPP (China)

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Table of contents




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Two European BB concepts in ITER

Europe will test in ITER two DEMO breeder blankets concepts under the form of Test Blanket Modules (TBMs) Systems:

Helium-Cooled Pebble-Bed (HCPB) Helium-Cooled Lithium-Lead (HCLL)

1,66 m

HCPB TBM

HCPBHe‐Cooled Pebble‐Bed

HCLLHe‐Cooled lithium‐Lead

Structural material EUROFER

Coolant Helium (8 MPa, 300‐500C)

Tritium breeder, neutron multiplier

Solid pebblesLi2TiO3 / Li4SiO4, Be

LiquidPb‐15.7Li

HCLL TBM

TBM sets in Equatorial Port #16 and TBS equipment inPort Cell


Two European TBM Systems in ITER

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2 Tritium Extraction/ Recovery Systems(Tritium Building)

2 Helium Cooling Systems2 Helium Purification Systems(CVCS Area)

1 Ancillary Equipment Unit and connection pipes(Port Cell)

2 TBMs and their Radiation Shield(Port Extension)

Helium‐Cooled Lithium‐Lead (HCLL) TBM

Helium‐Cooled Pebble‐Bed (HCPB) TBM

Breakdown of the EU TBS into subsystems


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Mission:The mission of the European TBM program is to test and validate during ITER operation the Helium‐Cooled Lithium‐Lead (HCLL) and the Helium‐Cooled Pebble‐Bed (HCPB) tritium breeding blanket concepts for application to fusion energy systems, with focus on DEMO.

Objectives:To meet this mission several “high‐level objectives” for TBM programme can be identified. They are:

Validation of the structural integrity theoretical predictions under combined and relevant loads Validation of the tritium breeding predictions Validation of tritium recovery process efficiency and T‐inventories in the blanket materials Validation of thermal predictions for strongly heterogeneous breeding blanket concepts with

volumetric heat sources Validation of the blanket power removal predictions Demonstration of the integral performance of the blanket systems.

Mission and objectives of the TBM Program


ITER Experimental Programme


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In order to perform a comprehensive experimental campaign under the different ITER operatingconditions, TBMs will be replaced several times, each time with a specific TBMdesign/instrumentation version but with all versions always corresponding to the same DEMObreeding blanket concept.

At the same time each TBM version will have to adapt to the operational plan of ITER thatforesees different plasma phases with very different operating conditions, from the initial H/He‐pulses (without neutrons) to a high‐duty D‐T phase after several years of operations (long pulsesup to about 3000 s and back‐to‐back pulses for several days), passing through the D‐phase and thelow‐duty D–T phase.

Depending on the TBM version and related operating conditions, it will be possible to performspecific experiments in the different fields such as neutronics, thermo‐mechanics, magneto‐hydrodynamics (MHD) and electromagnetic (EM), tritium control and management.

Implementation of the TBM Program objectives


3rd IAEA DEMO Programme Workshopg, 11-15 May 2015, ASIPP (China) 10

Today1) We learn to built it!!! Return on experience(very important because the choice between different alternatives should notbe made based only on R&D results)

In the future1) We will learn on MHD issues2) We will learn on Neutronics issues3) We will learn on Tritium4) We will learn on EMBut all these topics requires modelling and measuring capabilities –now underdevelopment‐

What can we learn from the EU ITER TBM Systems?

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TBM Systems will test technological solutions

Concept studies and basic R&D are not sufficient to decide on selection/ranking of concept(s)

Need for ROX (Return On eXperience) − Implementation of regulatory obligations (e.g.

ESPN, waste disposal, etc.)− Methodology for integration of new

materials/fabrication in C&S− Involvement of Industry, cost− Availability (failures database)− Performances under tokamak actual and multi‐

loadings conditions (B, n, heat flux)

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HCLL-DEMO

HCLL-TBM

Test in ITER

The Test Blanket Module (TBM) Program in ITER is organizing the implementation & test of blankets technological solutions:− Test in tokamak (ITER)− Regulatory obligations (ITER nuclear plant, ASN)− Involvement of Industry; project budgetary

constraints; etc.


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Few examples of return on experience gained through TBM systems design & qualification


Activity Interaction with

Introduction of EUROFER in RCC‐MRx

RCC‐MRx Committee • Conditions of acceptance of design limits (statistics, justification, specific behaviors, etc.)

• Conditions of acceptance of new design rules

ESP(N) classification of TBM and ancillary systems

ASNAgreed Notified Body

• Validation of the classification strategy and definition of max. allowable pressure PS (e.g. discrimination between small/large in‐box leakage)

• Verification of possibility to request an exemption or not• Clarification of the certification strategy and of in‐service re‐qualification

vs accessibility for inspection• Interpretation of ASN Guidelines (e.g. No19)

Standardization of TBM box fabrication

IO Integrator/OperatorIndustry

• Consequence of Tokamak standards (e.g. Vacuum Handbook) on fabrication requirements

• Development of Welding Procedure Specifications based on existing professional standards

• Validation of a the qualification route (e.g. ISO 15613:2004)

Radwaste Management ANDRAIO OperatorAIF

• Verification of materials acceptability• Identification of treatments needed before disposal• Verification of radwaste transport condition (package type, specific

safety demonstration)• Cost of disposal

Design and performance validation of ancillary systems

IndustryEFLsIO Integrator

• Verification of Blanket operational domain• Consistency with global Tokamak safety demonstration (e.g. PIS,

continuity of the 1st confinement barrier, etc.)

Safety IO OperatorASN

• Validation of the safety functions; consistent architecture of systems• Development of modeling tools

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Electrical flow coupling

Flow bending + narrow gap

3D expansions/ contractions

Buoyancy phenomena

Complex MHD sensitive design


MHD experimental campaign in ITER

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Gaining knowledge about complex coupled physical phenomena occurring in a fusion reactor environment (e.g. magneto‐convection, electromagnetic coupling) broadening and confirming available results coming from smaller

experimental facilitiesCreating a data base of benchmarks to validate the various stages of the ongoing development of numerical MHD codes Verifying and quantifying effects of stray magnetic field, electrical disturbances and real working conditions on the instrumentationCollecting data and operating experience for applications of HCLL blankets in a DEMO reactor suggesting suitable design modifications for improved performance of a DEMO blanket


Objectives

3rd IAEA DEMO Programme Workshop, 11‐15 May 2015, ASIPP (China) 16

Forced flow isothermal experiments (no plasma/no heat flux) To Investigate separately MHD phenomena: there is no coupling to heattransfer processes, where buoyancy may play an important role. Data used tovalidate theoretical predictions of pressure and flow distribution in the TBM.

Imposed heat flux in BUs (no plasma): heated plates and defined heatextraction through neighboring cooling plates To study natural (buoyancy effects) and mixed convection. Outcomes

used to select and validate numerical models for magneto‐convection.

Imposed thermal power and first wall heat flux (with plasma) To analyze coupled MHD and heat transfer phenomena under realistic operatingconditions (study of overall blanket performance)


Experiments


Applicability of sensors in fusion LM blanket environment (T 550°C,strong magnetic field B, T and B gradients, flowing PbLi, corrosion)

Material production/selection (max T and PbLi compatibility) Quantification of thermoelectric and magnetic field effects required

Achievable measurement accuracy due to small velocities in ITER TBM:signals are very small (influence of electromagnetic disturbances)

Lack of space (design integration constraints) Need to optimize number and size of sensors, to define proper

integration of instruments in the TBM (e.g. cable arrangement…)

MHD flows with buoyancy effects and mixed convection

Global electromagnetic coupling for complex 3D flows


Open issues


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Neutronics experimental campaign in ITER

Along with heat flux, is the source term of test conditions in the TBM, from thermo‐mechanical loads to tritium generation

ITER neutron wall load (source term) not uniformEffect of surrounding components enhanced by 120 mm recess

Neutron flux (and power density) strongly attenuated radiallyEffect of breeder and multiplier materialsUp to 80% attenuation

Energy distribution strongly modified in the TBM volumeThe contribution of high neutron energy component (E>1MeV) decreases from 37% in the front to about 13% in the rear zone

Why do we need to measure the neutron field inside TBMs?Toroidal‐poloidal distribution of n wall loading for the HCPB TBM U. Fischer, et al., Fusion Engineering and Design 86 (2011) 2176

Radial power density distribution in the HCPB TBM

Neutron flux spectra at different radial positions of the HCLL TBM, expressed in distance (cm) from the FW


Neutron flux and spectrum (at several positions to verify prediction from calculations)Gamma flux and spectrum (at several positions to verify prediction from calculations)Tritium production rate (during pulses, at several positions to verify prediction from calculations)Shielding capability (to very predicted radiation safety for people and environment)Nuclear heating and heating rate distribution (for verifying predicted structural integrity and energy extraction)Materials activation (Radiation safety: relevant to operation, maintenance and decommissioning; this will validate theoretical prediction)He and H (gas) production in structural materials


Objectives


The TBM Neutron Activation System

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).

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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.

6‐8 mm

15 mm

3 positions for each TBM considered in conceptual design

Preliminary capsule designIrradiation end integration in HCPB BU


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Why using activation foils for TBMs? Flexibility

NAS is used in DD and early DT phase to evaluate spectrum and for calibration of active sensors. 2 types of active sensors deployed in DT phase.

Absolute measurement of local neutron flux intensity without in‐situ calibration

Wide measuring range by varying foil materials, exposure and counting period

Evaluation of the neutron energy distribution for both DT and DD plasmas

No burn‐up or cumulative radiation damages on the detectors

No passive effects of neutron and gamma fluxes and other operating conditions (dB/dt)

Measurement of additional neutronics responses (gamma field, tritium production rate, delayed neutrons)

Response (sensitivity) tailored during test campaign by variable operational parameters

Self‐powered neutron detectors (SPNDs)

Emitter material for DT neutron field conditions

Single crystal diamond detectors (SCDs)

Fission micro chambers (MFCs)

CEA MFCs for MEGAPIE


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gT(t)


Tritium experimental campaign in ITER

HCPB TBM System Process Flow Diagram

A physics‐based approach is followed to develop predictive tools and define testing in ITER TBM

Although the selection of technologies of TBM Tritium ancillary systems (TES, CPS) are not based on DEMO relevancy, the validation of the tritium breeding capability of the blanket concept relies mainly on the integral measurement of tritium concentration performed in such system during DT operation, and specifically in the Tritium Accountancy Station (TAS).

Calibration and validation test of the systems in HH, DD and early DT phase are therefore integral part of the experimental campaign. Such tests will also contribute to validate models for specific systems components, such as the TEU.



Objectives

Conceptual design of TAS (common to HCLL and HCPB)

H‐H phaseHH‐ #1 Tests for calibration of PFDM modelling module at the TBM EM channel(s).HH‐ #2 Testing CPS at TBM scale and transfer model checks and HH‐ #3 Testing TES (TEU+TRS) at TBM scale and model check and calibrations HH‐ #4 Assessment of global hydrogen (or deuterium) residence time in TBS HCLL + optimisation

D‐D phaseDD‐#1 Testing tritium breeding prediction vs local concentration measurements at LM channel DD‐#2 Checking FPD & system models of D/T transfers prediction between TBS

(TBM HCS CPS ISS/WDS, TBM TEU TRS ISS/WDS, ) DD‐#3 First tritium tracking and global tritium residence time assessment at TBS_N system with

uncertainties

D‐T phaseDT‐#1 Further testing tritium breeding prediction vs local concentration measurements at LM channel DT‐#2 Tritium tracking at TBM HCLL channel(s) levelDT‐#3 Checking FPD & system models of T‐transfers prediction between TBS

(TBMHCSCPSISS/WDS, TBMTEUTRSISS/WDS )DT‐#4 Tritium tracking at TBS_IN systems with uncertainties



Experiments (1)

The concentration of tritium in HCLL and HCPB TBS is measured online at the Tritium Accountancy StationThe development of sensors to measure the local concentration at the inlet/outlet of the TBM and in specific components of the systems would provide a substantial contribution to the fulfillment of the ITER‐TBM scientific mission, in particular for the HCLL liquid metal breeder Pb‐16Li



Open issue: local measurement of T concentration

Immersed tritium permeable capsule (Fe)

Pressure gauge External vacuum circuit with H/T detectors

Alternative: proton conductor electrochemical sensors

Reference technology: permeation capsule

Situation of the T predictive tool and link with test program needs in ITER

Tritium transport modeling tools developed on the basis of EcosimPRO

Framework Partnership Agreement for Modeling Development was launched (FPA‐611)

The validation of tritium transport predictive tools during ITER TBM operation is fundamental for the assessment of tritium self‐sufficiency of tested concepts

TRITIUM_TBM Library

TRITIUM_BALANCE Library

Simplified diagram of the

HCLL‐TBS model

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Tritium inventory in TBM vs. Tritium Extraction efficiency during a full day of inductive pulses in ITER; simulation code developed on

Ecosimpro platform




Proposal for coupled TBM/DEMO strategy for development of Tritium Predictive tool


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EM experimental campaign in ITER

TBM design analysis rely on complex electro‐magnetic models to account for the effect of ferromagnetic materials on ITER magnetic field

ITER TBM test will measure the B field around the TBM and validate the predictive tools (Hall sensors)

Additional potential probes are under development to measure induced current on the TBM structure for further validation and reconstruction of EM forces

Proposed Hall sensors for TBMs (KIT/Efremov). Both sensors and probes are mounted on the box outer surface, without penetration

3rd IAEA DEMO Programme Workshopg, 11-15 May 2015, ASIPP (China) 33

Conclusions

Today1) We learn to built it!!! Return on experience(very important because the choice between different alternatives should notbe made based only on R&D results)

In the future1) We will learn on MHD issues2) We will learn on Neutronics issues3) We will learn on Tritium4) We will learn on EMBut all these topics requires modelling and measuring capabilities –now underdevelopment‐

What can we learn from the EU ITER TBM Systems?

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what can be measured in, what eu iter tbm systems · 2016. 5. 5. · what can be measured in, what...

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