Spallation%20Target%20R

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Spallation Target RD for the EUAccelerator-Driv
en Sub-critical System Project
Y. Kadi (AB/ATB) European Organization for
Nuclear Research, CERN CH-1211 Geneva 23,
SWITZERLAND yacine.kadi_at_cern.ch
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ISOL thick target
UC2 target
Mass-Separation
Ionisation Effusion
DiffusionNuclear reaction
RILIS laser beams
Time
Nb cavity
Transfer line
UC2 pills
Graphite sleeve
Tantalum oven
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ISOL targets materialsspallation - fission
Z
Users request frequency
Refractory compounds Oxides, carbides,
chlorides Molten metals, Molten salts, Thins
foils, powders
Target thickness 4-220 g/cm2
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High energy protons fission of 238U and
n-induced fission of 235U
Fragments
Spallation
Fission
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ISOLDE target handling.
Class A laboratory (2004) SIsotopes (Activity/LA)
gt 10000
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Use of Spallation Neutrons

• Spallation neutrons can be used to transmute the
  highly-radiotoxic nuclei which are present in
  nuclear waste into stable or very short lived
  isotopes that can be disposed off safely.
• The techniques developed for ADS can be applied
  to optimize the production of fission products of
  the EURISOL-DS.
• . A long way to go but clear synergies in the
  neutronics .

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Transmutation of Nuclear Waste ?

• Europe 35 of electricity from nuclear energy
• produces about 2500 t/y of used fuel 25 t (Pu),
  3.5 t (MAs Np, Am, Cm) and 3 t (LLFPs).
• social and environmental satisfactory solution is
  needed for the waste problem
• The PT in association with the ADS can lead to
  this acceptable solution.

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Transmutation of Nuclear Waste ? (2)
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Sub-Critical Systems (1)

• In Accelerator-Driven Systems a Sub-Critical
  blanket surrounding the spallation target is used
  to multiply the spallation neutrons.

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Sub-Critical Systems (2)
? ADS operates in a non self-sustained chain
reaction mode ? minimises criticality
and power excursions ? ADS is
operated in a sub-critical mode ? stays
sub-critical whether
accelerator is on or off ? extra level of safety
against criticality
accidents ? The accelerator provides a control
mechanism for sub-critical systems ? more
convenient than control
rods in critical reactor ? safety concerns,
neutron economy ? ADS provides a
decoupling of the neutron source (spallation
source) from the fissile fuel (fission
neutrons) ? ADS accepts fuels that would not be
acceptable in critical reactors ? Minor
Actinides ? High Pu content ? LLFF...
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The FEAT Experiment (1)
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The FEAT Experiment (2)
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The FEAT Experiment (3)
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The Energy Amplifier Concept
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The Energy Amplifier Concept (2)
?Method A high energy proton beam interacts in a
molten lead (Pb-Bi) swimming pool. Neutrons are
produced by the so-called spallation process.
Lead is transparent to neutrons. Single phase
coolant, b.p. 2000 C ?TRU They are
introduced, after separation, in the form of
classic, well tested fuel rods. Fast neutrons,
both from spallation and fission, drift to the
TRU rods and fission them efficiently. A
substantial amount of net power is produced (up
to 1/3 of LWR), to pay for the
operation. ?LLFF Neutrons leaking from the
periphery of the core are used to transmute also
LLFF (Tc99, I129 ....) ?Safety The
sub-criticality (k 0.95?0.98) condition is
guaranteed at all times.
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The Energy Amplifier Concept (3)
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The Three Levels of ADS Validation

• Three different levels of validation of an ADS
  can be specified
• First, validation of the different component
  concepts, taken separately (accelerator, target,
  subcritical core, dedicated fuels and fuel
  processing methods). In Europe The FEAT, TARC
  MUSE experimental programs and the MEGAPIE
  project are significant examples.
• Second, validation of the coupling of the
  different components in a significant
  environment, e.g. in terms of power of the global
  installation, using as far as possible existing
  critical reactors, to be adapted to the
  objectives.
• Third, validation in an installation explicitly
  designed for demonstration (e.g. the ADS
  installation described in the European roadmap
  established by the Technical Working Group,
  chaired by prof. Rubbia). This third step should
  evolve to a demonstration of transmutation fuels,
  after a first phase in which the subcritical core
  could be loaded with standard fuel.

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ADS VALIDATION Level 1

• Physics Basic underlying physics has been
  thoroughly checked at zero power in particular by
  experiments at CERN and elsewhere
• ? Spallation process and neutron yields with
  proton beam in a wide range of energies
• ? Fission rates and lead nuclear properties a
  sub-critical arrangement with k0.9 has
  demonstrated energy gain in agreement with
  calculations (FEAT Experiment)
• ? Transmutation rates for most offending LLFP.
  Fast elimination by adiabatic resonance
  crossing has been demonstrated experimentally
  for 129I and 99Tc. (TARC Experiment)
• ? Most key reactions fully tested at low power
  level
• ? A comprehensive programme of neutron induced
  cross-section measurements has been started (nTOF
  Project)

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ADS VALIDATION The TARC Experiment (1)

• Simulation of neutrons produced by a single
  3.5 GeV/c proton
• (147 neutrons produced, 55035 scattering)

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ADS VALIDATION The TARC Experiment (2)
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ADS VALIDATION The TARC Experiment (3)
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ADS VALIDATION Level 1

• We are now at a turning point in terms of
  programme co-ordination and resource deployment
  in Europe. For the coming five to seven years,
  the RD should concentrate on
• The development of high intensity accelerators
  and megawatt spallation sources, and their
  integration in a fissile facility
• The development of advanced fuel reprocessing
  technology
• Throughout Europe, the main facilities or
  experiments of relevance are
• IPHI (High Intensity Proton Injector) in France
  and TRASCO (TRAsmutazione SCOrie) in Italy, on
  the design of a high current and reliable proton
  linear accelerator.
• MEGAPIE (MEGAwatt PIlot Experiment), a robust and
  efficient spallation target, integrated in the
  SINQ facility at the Paul Scherrer Institute in
  Switzerland. The SINQ facility is a spallation
  neutron source fed by a 590 MeV proton cyclotron.

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ADS VALIDATION Level 1

• MUSE-4 (At the MASURCA installation in
  CEA-Cadarache, using the GENEPI Accelerator), as
  a first image of a sub-critical fast core fed by
  external neutrons.
• JRC-ITU The Minor Actinide (fuel fabrication) and
  advanced aqueous and pyro-processing Laboratories
  at JRC-ITU in Karlsruhe.
• JRC-IRMM Neutron data activity at Gelina TOF
  Facility in Geel.
• N_TOF (Neutron Time of Flight) experiment at
  CERN, Geneva, for nuclear cross-section
  measurements.
• KALLA (KArlsruhe Lead LAboratory) and
• CIRCE (CIRCuito Eutettico) facilities for Pb and
  Pb-Bi Eutectic technology development in
  Brasimone, Italy.

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ADS VALIDATION CIRCE Pb PbBi test facility
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ADS VALIDATION MEGAPIE test

• MEGAPIE Project at PSI
• 0.59 GeV proton beam
• 1 MW beam power
• Goals
• Demonstrate feasablility
• One year service life
• Irradiation in 2005

Proton Beam
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The Three Levels of ADS Validation

• Three different levels of validation of an ADS
  can be specified
• First, validation of the different component
  concepts, taken separately (accelerator, target,
  subcritical core, dedicated fuels and fuel
  processing methods). In Europe The MUSE
  experimental program and the MEGAPIE project are
  significant examples.
• Second, validation of the coupling of the
  different components in a significant
  environment, e.g. in terms of power of the global
  installation, using as far as possible existing
  critical reactors, to be adapted to the
  objectives.
• Third, validation in an installation explicitly
  designed for demonstration (e.g. the ADS
  installation described in the European roadmap
  established by the Technical Working Group,
  chaired by prof. Rubbia). This third step should
  evolve to a demonstration of transmutation fuels,
  after a first phase in which the subcritical core
  could be loaded with standard fuel.

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ADS VALIDATION Level 2 TRADE Project

• The TRADE experiment suggested by C. Rubbia,
  first worked-out in an ENEA/CEA/CERN feasibility
  study and presently assessed by a wider
  international group (lead ENEA, CEA, DOE, FZK),
  is a significant step towards the ADS
  demonstration, i.e. within the second step of ADS
  validation
• Coupling of a proton accelerator to a power TRIGA
  Reactor via a spallation target, inserted at the
  center of the core.
• Range of power 
• in the core  200 - 1000 KW,
• in the target  20 - 100 KW.
• The main interest of TRADE, as compared to the
  MUSE experiments, is the ability of incorporating
  the power feedback effects into the dynamics
  measurements in ADS and to address ADS
  operational, safety and licensing issues.

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The TRADE Facility - Reactor and Accelerator
Buildings
Control Room Window
Cyclotron (section)
Beam Pipe
Core Reactor
Shielded Beam Pipe Tunnel
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Overall Lay-out of the TRADE Facility
Top view bending magnets
Core cross-section
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TRIGA MARK II REACTOR
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TRIGA MARK II REACTOR
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The main characteristics of TRADE

• A proton cyclotron delivering a beam of 140 MeV
  protons (option investigated ? 300 MeV).
• A three sections beam transport line Matching
  section/Straight transfer line/Final bending
  line.
• A solid Ta target (back-up  W clad in Ta).
• Forced convection of the target cooling with a
  separate loop.
• Natural convection for the core cooling.
• Range of subcritical levels  k  0.90 ? 0.99

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The Spallation Target System
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Primary Flux
Thick Ta Target (protons/cm2/s) per mA - 140 MeV -
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Primary Flux
Thick Ta Target (protons/cm2/s) per mA - 300 MeV -
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H-E Neutron Flux _at_ 140 MeV
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H-E Neutron Flux _at_ 300 MeV
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Radiation Damage
Gas production and the displacement rates per kW
of beam
Target (Ta) Average Prot. Ener(MeV) Average Neut. Ener(MeV) H3 Production(appm/dpa) He Production(appm/dpa) HE proton(dpa/yr) HE neutron(dpa/yr)
Max Ave
140 MeV 90 51 0.99 54.8 0.6 0.07
200 MeV 115 65 2.92 130. 0.5 0.05
300 MeV 155 88 6.93 275. 0.4 0.04
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Target cooling system in forced convection

• Coarse Dimensioning of the circuit
• Thermal power 40kW
• Design ?T 5 - 20 C
• Pumps and circuit characteristics
• Pumps flow-rate 8 - 2 m3/h
• Water max speed (3 holes of F 18 mm) 3 - 1
  m/s

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Target cooling system in forced convection
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Target cooling system in forced convection
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Target cooling system in forced convection
In presence of the design mass flow-rate of water
(2.24 Kg/s), the maximum thermal flux at the
outer wall of the target is 135 w/cm2 thus
assuring a margin large enough to prevent the
occurrence of Critical Heat Flux. Moreover the
maximum temperature is 80C which is
significantly lower than the TRIGA saturation
temperature
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Test loop configuration to be built at FzK
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The Three Levels of ADS Validation

• Three different levels of validation of an ADS
  can be specified
• First, validation of the different component
  concepts, taken separately (accelerator, target,
  subcritical core, dedicated fuels and fuel
  processing methods). In Europe The MUSE
  experimental program and the MEGAPIE project are
  significant examples.
• Second, validation of the coupling of the
  different components in a significant
  environment, e.g. in terms of power of the global
  installation, using as far as possible existing
  critical reactors, to be adapted to the
  objectives.
• Third, validation in an installation explicitly
  designed for demonstration (e.g. the ADS
  installation described in the European roadmap
  established by the Technical Working Group,
  chaired by prof. Rubbia). This third step should
  evolve to a demonstration of transmutation fuels,
  after a first phase in which the subcritical core
  could be loaded with standard fuel.

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Spallation Target Boundary Conditions
MYRRHA Project 50 - 80 MWth (k0.97)

• 350 MeV, 5 mA proton beam for fast neutron fluxes
  for transmutation, i.e. 1.75 MW of which 80 is
  heat
• 130 mm penetration depth for 350 MeV - Bragg peak
• 72 mm ID radial extent of the beam tube 122 mm
  OD radial extent of the feeder - limited by
  neutronics
• Windowless target due to high beam load - despite
  vacuum
• Pb-Bi because of neutronic and thermal properties

• 1.4 MW heat in 0.5 l to be removed while
  meeting thermal and vacuum requirements

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Spallation Target Desired Target Configuration
BEAM
Fast core
Volume-minimized recirculation zone gets lower
tailored heat input
Example of radial tailoring
Irradiation samples
High-speed flow (2.5 m/s) permits effective heat
removal
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Spallation Loop Technical Lay-Out
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Spallation TargetDesign and RD Approach

• Interaction between
• Experiments with increasing complexity and
  correspondence to the real situation
  (H2OHgPbBi)
• CFD simulations to
• predict experimental results
• optimize nozzles for experiments
• simulate heat deposition which can not yet be
  simulated experimentally

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Hg Experiments at IPUL

• 8 ton Hg
• Q up to 11 l/s
• Vacuum above free surface lt 0.1 mbar
• Minimal pump load is necessary (to avoid pump
  cavitation)

• Main flow
• Adding/Removing Hg from cylinder
• Vacuum system

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DG16.5 Hg Experiments
nominal volume flow 10 l/s

• Close to desired configuration !
• intermediate lowering of level
• some spitting
• axial asymmetry

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DG16.5 H2O Experiments
nominal volume flow 10 l/s vacuum pressure 22 mbar

• Similarity check OK !

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Spallation Target Future Steps

• Pb-Bi Experiments at FZK (KALLA)
• Similar size as IPUL loop
• Similar complexity as MYRRHA loop 2 free surface
  mechanical impeller pump
• fall 2005

• Pb-Bi Experiments at ENEA (CHEOPE)
• Minimum closed loop configuration
• MHD pump
• Speed feedback regulation test
• fall 2005

• Proton beam heating
• Simulation with CFD code (e.g. FLOW-3D)
• Simulated or measured flow field

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RD Program Partnership Network

• Accelerator ? IBA (B)
• Spallation source
• Basic spallation data ? NRC Soreq (I) PSI (CH)
• Feasibility of the windowless design ? UCL (B)
  FZR (D) FZK(D) NRG (NL) CEA (F) ENEA (I)
  IPUL (Latvia)
• Compatibility of the free surface with the proton
  beam line vacuum ?ATL (UK) , SDMS (F)
• Subcritical assembly ? ENEA (I) CEA (F) BN
  (B) UoK-UI (LT), IPPE GIDROPRESS (Russia),
  TEE (B), CIEMAT (Sp), RIAR (Russia)
• Safety ? TEE (B), AVN (B) FANC (B) (Information
  contacts)
• Robotics ? OTL (UK)
• Building ? IBA (B), OTL (UK)

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Outline of the results WP4/Target studies

• Design accommodate different target styles
• LBE reactors can accommodate liquid LBE target
  with both window and windowless concepts
• Gas cooled XADS relies on liquid LBE window
  target with solid target as back-up solution
• Different engineering variants have been
  developed to account for specific requirements

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Outline of the results WP4/Target studies

• Design accommodate different target styles
• Lifetime of the window cannot be established (at
  6 mA / 600 MeV max. damage of window is 54
  dpa/Gas production in 3 months) (viability to be
  reconsidered after MEGAPIE integral test and RD)

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Outline of the results WP4/Target studies

• For the LBE-cooled XADS and MYRRHA, the
  Windowless Target Unit option presents more
  merits in term of less Reactor Roof activation,
  longer lifetime and reduced need of material
  qualification (to be further developed
  supported by RD CFD/Vacuum system/pumps)
• For the Gas, the solid Target cooled by He seems
  the most coherent choice and shall improve the
  window integrity/maintenance aspects. Very early
  stage , shall be developed (focus on beam
  shutdown aspects)

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Interface with WP 4.3 Preliminary solid target
arrangement

• "Cold window concept"

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FP6 IP-EUROTRANS
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SP4 DEMETRA

• The objective is to develop and assess the heavy
  liquid metal (HLM) technologies for ADS
• applications, the heavy liquid metal being both
  the spallation material and/or the primary
• coolant. The main results obtained during FP5 are
  a first screening on the compatibility of
• structural materials with the HLM, comprehension
  of basic corrosion phenomena, oxygen
• control, measurement techniques, and
  thermalhydraulics (TECLA), preliminary evaluation
• on the mechanical behaviour of martensitic steels
  irradiated both in proton and neutron
• fields and simulation of spallation element
  effects (SPIRE), design and operation of a 1 MW
• spallation target (MEGAPIE-TEST). The proposed
  work plan address the following tasks
• Performance of ETD relevant large-scale
  experiments in the CIRCE and KALLA facilities for
  the characterisation and validation of primary
  system components and a full size spallation
  target module, in combination with a detailed
  thermalhydraulic-thermomechanic assessment under
  steady-state and transient conditions.
• Characterisation of structural materials in terms
  of corrosion kinetics, corrosion protection and
  mechanical properties degradation, with and
  without combined proton and neutron irradiation.
• Development and demonstration of measurement
  techniques to be applied in large-scale
  facilities and their feasibility of upgrade for
  future industrial applications.
• Performance and assessment of the MEGAPIE post
  test analysis and post irradiation examination
  (PIE) quantification of the transferability of
  the results to ETD conditions.

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Worldwide Programs
Project Neutron Source Core Purpose
MUSE (France) DT (1010n/s) Fast (lt 1 kW) Reactor physics of fast subcritical system
TRADE (Italy) Proton (140 MeV) Ta (40 kW) Thermal (200 kW) Demonstration of ADS with thermal feedback
TEF-P (Japan) Proton (600 MeV) Pb-Bi (10W, 1012n/s) Fast (lt 1 kW) Coupling of fast subcritical system with spallation source including MA fueled configuration
SAD (Russia) Proton (660 MeV) Pb-Bi (1 kW) Fast (20 kW) Coupling of fast subcritical system with spallation source
MYRRHA (Belgium) Proton (350 MeV) Pb-Bi (1.75 MW) Fast (35 MW) Experimental ADS
MEGAPIE (Switzerland) Proton (600 MeV) Pb-Bi (1MW) ----- Demonstration of 1MW target for short period
TEF-T (Japan) Proton (600 MeV) Pb-Bi (200 kW) ----- Dedicated facility for demonstration and accumulation of material data base for long term
Reference ADS Proton ( 1 GeV) Pb-Bi ( 10 MW) Fast (1500 MW) Transmutation of MA and LLFP
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Conclusions

• Transmutation of nuclear waste is establishing
  the case for the development of new high-power
  proton drivers.
• High-power targets are necessary for the
  exploitation of these new machines.
• Target systems have been developed for the
  initial 1MW class machines, but are as yet
  unproven.
• No convincing solution exists as yet for the
  envisioned 4 MW class machines.
• A world wide RD effort is under way to develop
  new high-power targets.