Title: Spallation%20Target%20R
1Spallation 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
2ISOL thick target
UC2 target
Mass-Separation
Ionisation Effusion
DiffusionNuclear reaction
RILIS laser beams
Time
Nb cavity
Transfer line
UC2 pills
Graphite sleeve
Tantalum oven
3ISOL 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
4High energy protons fission of 238U and
n-induced fission of 235U
Fragments
Spallation
Fission
5ISOLDE target handling.
Class A laboratory (2004) SIsotopes (Activity/LA)
gt 10000
6Use 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 .
7Transmutation 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.
8Transmutation of Nuclear Waste ? (2)
9Sub-Critical Systems (1)
- In Accelerator-Driven Systems a Sub-Critical
blanket surrounding the spallation target is used
to multiply the spallation neutrons.
10Sub-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...
11The FEAT Experiment (1)
12The FEAT Experiment (2)
13The FEAT Experiment (3)
14The Energy Amplifier Concept
15The 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.
16The Energy Amplifier Concept (3)
17The 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.
18ADS 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)
19ADS VALIDATION The TARC Experiment (1)
- Simulation of neutrons produced by a single
3.5 GeV/c proton - (147 neutrons produced, 55035 scattering)
20ADS VALIDATION The TARC Experiment (2)
21ADS VALIDATION The TARC Experiment (3)
22ADS 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.
23ADS 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.
24ADS VALIDATION CIRCE Pb PbBi test facility
25ADS 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
26The 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.
27ADS 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.
28 The TRADE Facility - Reactor and Accelerator
Buildings
Control Room Window
Cyclotron (section)
Beam Pipe
Core Reactor
Shielded Beam Pipe Tunnel
29 Overall Lay-out of the TRADE Facility
Top view bending magnets
Core cross-section
30TRIGA MARK II REACTOR
31TRIGA MARK II REACTOR
32The 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
33The Spallation Target System
34Primary Flux
Thick Ta Target (protons/cm2/s) per mA - 140 MeV -
35Primary Flux
Thick Ta Target (protons/cm2/s) per mA - 300 MeV -
36H-E Neutron Flux _at_ 140 MeV
37H-E Neutron Flux _at_ 300 MeV
38Radiation 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
39Target 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
40Target cooling system in forced convection
41Target cooling system in forced convection
42Target 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
43Test loop configuration to be built at FzK
44The 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.
45Spallation 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
46Spallation 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
47Spallation Loop Technical Lay-Out
48Spallation 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
49Hg 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
50DG16.5 Hg Experiments
nominal volume flow 10 l/s
- Close to desired configuration !
- intermediate lowering of level
- some spitting
- axial asymmetry
51DG16.5 H2O Experiments
nominal volume flow 10 l/s vacuum pressure 22 mbar
52Spallation 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
53RD 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)
54Outline 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
55Outline 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)
56Outline 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)
57Interface with WP 4.3 Preliminary solid target
arrangement
58FP6 IP-EUROTRANS
59SP4 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.
60Worldwide 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
61 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.