1. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 1 Spallation Target R&D for the EU Accelerator-Driven Sub-critical System Project Y. Kadi (AB/ATB) European Organization for Nuclear Research, CERN CH-1211 Geneva 23, SWITZERLAND yacine.kadi@cern.ch

2. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 2 ISOL thick target RILIS laser beams Nb cavity Tantalum oven Transfer line Diffusion Mass-Separation Ionisation Effusion Diffusion Nuclear reaction UC 2 pillsGraphite sleeve UC 2 target Time

3. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 3 Refractory compounds: Oxides, carbides, chlorides Molten metals, Molten salts, Thins foils, powders ISOL targets materials spallation - fission Z Users’ request frequency Target thickness: 4-220 g/cm 2

4. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 4 High energy protons fission of 238 U and n-induced fission of 235 U Fission Spallation Fragments

5. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 5 ISOLDE target handling. Class A laboratory (2004)  Isotopes ( Activity/LA) > 10’000

6. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 6 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 …….

7. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 7 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 P&T in association with the ADS can lead to this acceptable solution.

8. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 8 Transmutation of Nuclear Waste ? (2)

9. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 9 Sub-Critical Systems (1) In Accelerator-Driven Systems a Sub-Critical blanket surrounding the spallation target is used to multiply the spallation neutrons.

10. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 10 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...  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...

11. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 11 The FEAT Experiment (1)

12. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 12 The FEAT Experiment (2)

13. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 13 The FEAT Experiment (3)

14. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 14 The Energy Amplifier Concept

15. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 15 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 (Tc 99, I 129....)  Safety: The sub-criticality (k ≈ 0.95  0.98) condition is guaranteed at all times.

16. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 16 The Energy Amplifier Concept (3)

17. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 17 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.

18. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 18 ADS VALIDATION: Level 1 PhysicsBasic 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 k≈0.9 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 129 I and 99 Tc. (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)

19. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 19 ADS VALIDATION: The TARC Experiment (1) Simulation of neutrons produced by a single 3.5 GeV/c proton (147 neutrons produced, 55035 scattering) Simulation of neutrons produced by a single 3.5 GeV/c proton (147 neutrons produced, 55035 scattering)

20. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 20 ADS VALIDATION: The TARC Experiment (2)

21. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 21 ADS VALIDATION: The TARC Experiment (3)

22. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 22 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 R&D 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.

23. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 23 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.

24. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 24 ADS VALIDATION: CIRCE Pb & PbBi test facility

25. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 25 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

26. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 26 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.

27. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 27 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.

28. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 28 The TRADE Facility - Reactor and Accelerator Buildings Core Reactor Cyclotron (section) Beam Pipe Shielded Beam Pipe Tunnel Control Room Window

29. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 29 Overall Lay-out of the TRADE Facility Overall Lay-out of the TRADE Facility Core cross-section Top view & bending magnets

30. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 30 TRIGA MARK II REACTOR

31. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 31 TRIGA MARK II REACTOR

32. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 32 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

33. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 33 The Spallation Target System

34. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 34 Primary Flux Thick Ta Target (protons/cm2/s) per mA - 140 MeV -

35. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 35 Primary Flux Thick Ta Target (protons/cm2/s) per mA - 300 MeV -

36. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 36 H-E Neutron Flux @ 140 MeV

37. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 37 H-E Neutron Flux @ 300 MeV

38. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 38 Radiation Damage Gas production and the displacement rates per kW of beam Target (Ta) Average Prot. Ener (MeV) Average Neut. Ener (MeV) H 3 Production (appm/dpa) He Production (appm/dpa) HE proton (dpa/yr) HE neutron (dpa/yr) MaxAve 140 MeV90510.9954.80.60.07 200 MeV115652.92130.0.50.05 300 MeV155886.93275.0.40.04

39. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 39 Target cooling system in forced convection Coarse Dimensioning of the circuit: Thermal power = 40kW Design ΔT ~ 5 - 20°C Pumps and circuit characteristics: Pumps flow-rate ~ 8 - 2m 3 /h Water max speed (3 holes of Φ = 18 mm)~ 3 - 1 m/s Coarse Dimensioning of the circuit: Thermal power = 40kW Design ΔT ~ 5 - 20°C Pumps and circuit characteristics: Pumps flow-rate ~ 8 - 2m 3 /h Water max speed (3 holes of Φ = 18 mm)~ 3 - 1 m/s

40. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 40 Target cooling system in forced convection

41. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 41 Target cooling system in forced convection

42. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 42 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 80°C which is significantly lower than the TRIGA saturation temperature

43. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 43 Test loop configuration to be built at FzK

44. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 44 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.

45. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 45 Spallation Target: Boundary Conditions 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 MYRRHA Project: 50 - 80 MWth (k≈0.97)

46. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 46 Spallation Target: Desired Target Configuration Volume-minimized recirculation zone gets lower ‘tailored’ heat input Example of radial tailoring High-speed flow (2.5 m/s) permits effective heat removal Irradiation samples Fast core BEAM

47. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 47 Spallation Loop Technical Lay-Out

48. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 48 Spallation Target: Design and R&D Approach Interaction between: Experiments with increasing complexity and correspondence to the real situation (H 2 O–Hg–PbBi) CFD simulations to –predict experimental results –optimize nozzles for experiments –simulate heat deposition which can not yet be simulated experimentally

49. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 49 Hg Experiments at IPUL  Main flow  Adding/Removing Hg from cylinder  Vacuum system 8 ton Hg Q up to 11 l/s Vacuum above free surface < 0.1 mbar Minimal pump load is necessary (to avoid pump cavitation)

50. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 50 DG16.5 Hg Experiments nominal volume flow 10 l/s 60 16.5° Close to desired configuration !  intermediate lowering of level  some spitting  axial asymmetry

51. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 51 DG16.5 H 2 O Experiments nominal volume flow 10 l/s vacuum pressure 22 mbar  Similarity check: OK !

52. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 52 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

53. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 53 R&D 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)

54. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 54 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

55. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 55 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 R&D)

56. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 56 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 R&D : 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)

57. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 57 "Cold window concept" Interface with WP 4.3 – Preliminary solid target arrangement

58. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 58 FP6 IP-EUROTRANS

59. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 59 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.

60. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 60 Worldwide Programs ProjectNeutron SourceCorePurpose MUSE (France) DT (~10 10 n/s) Fast (< 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, ~10 12 n/s) Fast (< 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. BENE04, DESY Hamburg, GermanyY.KADINovember 2-5, 2004 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 R&D effort is under way to develop new high-power targets.