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Design and challenges for the SHIP target complex

First SHIP Workshop – 10-12 June 2014 - Zurich. Design and challenges for the SHIP target complex. M. Calviani , A. Ferrari, R. Losito, A. Perillo-Marcone, R. Folch, V. Venturi Engineering Department (EN) Sources, Targets and Interactions (STI) Group . Outline. SHIP target station design

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Design and challenges for the SHIP target complex

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  1. First SHIP Workshop – 10-12 June 2014 - Zurich Design and challenges for the SHIP target complex M. Calviani, A. Ferrari, R. Losito, A. Perillo-Marcone, R. Folch, V. Venturi Engineering Department (EN) Sources, Targets and Interactions (STI) Group

  2. Outline M. Calviani - Design and challenges for the SHIP target complex • SHIP target station design • Preliminary thoughts and challenges • SHIP production target • Issues and present conception • Conclusions and perspectives

  3. Target areas at CERN WANF & CNGS Antiproton target n_TOF (neutrons) beam TCC2 M. Calviani - Design and challenges for the SHIP target complex • CERN target areas are generally halls, pits or long tunnels, far from the access points • Activated air has enough time to decay and stray radiation is not a problem for the public • Neutrino ones are generally deep in the molasses (e.g. CNGS)

  4. SHIP target station design • Due to the shallow depth of the beam line (~14 meters), a target area approach based on long tunnels (i.e. CNGS, WANF, etc.) is not applicable • A multi-compartment solution similar to T2K/NuMI has been therefore developed, taking into account the specificities of CERN M. Calviani - Design and challenges for the SHIP target complex • The SHIP TS preliminary design takes advantage of the activities for CENF • Shallow target installation, multi-compartment solution • Underground areas accessible from the target hall

  5. M. Calviani - Design and challenges for the SHIP target complex

  6. Features of the SHIP target station Iron shielding to be water cooled (~O(100 kW)) M. Calviani - Design and challenges for the SHIP target complex • Production target installed inside an underground Fe shielded bunker, accessible from the top

  7. Features of the target station M. Calviani - Design and challenges for the SHIP target complex • Fully remote handling/manipulation of the target and shielding from the target hall • High residual dose rate (~tens of Sv/h!) • Helium environment enclosing the target and the shielding • Reduction of air activation and corrosion • Ventilation system according to ISO17874 • The idea is to have a pressure  dynamic confinement

  8. M. Battistin (EN/CV) M. Calviani - Design and challenges for the SHIP target complex

  9. This is what happens w/o control of the air chemistry (~at 20 kW) M. Calviani - Design and challenges for the SHIP target complex

  10. M. Calviani - Design and challenges for the SHIP target complex • Target hall above ground level • Outside area shall be non-designated during target manipulation • Ground-filled around target hall or heavy concrete walls • An additional (smaller) service building needed • Safety racks, EL cabinets (EBD, etc.), transformers, water treatment area, access, etc.

  11. View of the target hall and service buildings Access for transport and various additional services (EL, secondary water loops, etc.) 35 m Radioactive areas, accessible in shutdown Radioactive areas, no access 38 m M. Calviani - Design and challenges for the SHIP target complex

  12. Target station summary Challenging… but feasible M. Calviani - Design and challenges for the SHIP target complex • Target station shall be designed for a MW-class spallation target • Specific attention to radioprotection & environmental releases – well mastered and evaluated for CENF • CE works adapted to minimize water infiltration and in case treatment with evaporators • Shall be designed for long-term operation • Minimize time for target exchange in case of failure (physics downtime)

  13. Target design M. Calviani - Design and challenges for the SHIP target complex • The production target is the single most critical aspect of the target complex • As required by the experiment, W-based (i.e. high-Z) target • Long term reliability is a key factor in the design • Reduction of “waste” • Reduce downtime to minimum

  14. (Spallation) source • One of the most technologically challenging aspects of the proposed installation • In terms of average beam power on target would be similar to SNS (USA) or MLF (JP) • However, power during pulse would make it closer to ESS (almost 3 MW) Beam parameters M. Calviani - Design and challenges for the SHIP target complex

  15. Analysis method M. Calviani - Design and challenges for the SHIP target complex • Analysis assumes nominal operation, with both the baseline and ultimate beams • Steady state with transient analysis • Worst case scenario, i.e. target reaches steady state and then receives a high intensity pulse • Main preliminary results: • Full W cylinder will not withstand the compressive stresses (>2 GPa) and temperatures (>1200 °C) – target would fail • Target segmentation mandatory to allow decrease of temperatures and thus stresses

  16. Energy deposition and checks • FLUKA/ANSYS/CFX coupled calculations • Pure tungsten, 19.3 g/cm3 • 60 cm length, 20x20 cm2 • Beam on target: • Uniform circular sweep 3 cm radius, 1s 6 mm • Archimedean spiral, 5-35 mm radius (1s 6 mm) • 80% energy deposited in the target (300-400 kW) Target must be actively cooled (H2O considered for the moment) M. Calviani - Design and challenges for the SHIP target complex

  17. Preliminary Preliminary M. Calviani - Design and challenges for the SHIP target complex • Optimisation of the plate thickness still ongoing • Longitudinal gap of ~O(10-15 cm) • Peripheral + radial cooling to increase HTC High tangential velocities (5-10 m/s)!

  18. Thermo mechanical calculations • Caveat: • Conservative assumptions • Still lots of margins for improvement! M. Calviani - Design and challenges for the SHIP target complex • Considering the poor properties of W heavy alloys to high temperature and radiation we baselined pure W • ~780 °C, 900 MPa (worst case) • R&D needed!!!

  19. Accident scenario (no sweep) 3000 °C (below melting point at ~3400 °C) ~4.4 GPa compressive stress The target would not melt... But will fail! M. Calviani - Design and challenges for the SHIP target complex

  20. Radiation damage M. Calviani - Design and challenges for the SHIP target complex • Design shall assume that a target withstands the whole proposed POTs (2*1020) • ~1.2 DPA (displacement per atom) at 2*1020 POT • Big impact on the evolution of mechanical properties!

  21. Evolution of mechanical properties with radiation (and temperature) Yield stress increases with irradiation and decreases with temperature Reduction of ductility with irradiation S. A. Maloy et al., ICANSXX workshop (2012) S. A. Maloy, Materials Transactions, Vol. 43, No. 4 (2002) M. Calviani - Design and challenges for the SHIP target complex

  22. Crack formation on pure W samples under irradiation The central core of the SHIP target might potentially develop internal cracks due to radiation embrittlement, swelling and high temperature S. A. Maloy et al., ICANSXX workshop (2012) S.A. Maloy et al. / Journal of Nuclear Materials 343 (2005) 219–226 M. Calviani - Design and challenges for the SHIP target complex

  23. Target design preliminary assessment M. Calviani - Design and challenges for the SHIP target complex • The target must be segmented to reduce temperatures and compressive stresses • Very high flow rate required (cavitation, erosion/corrosion...) • Need to check “water hammer” effect on target/cooling circuits • Full control of water chemistry (à-la-n_TOF) • Vigorous R&D should be launched on material properties and their evolution with radiation and temperature • Ta-cladded W, WRe alloys, K-doped W alloys, etc.

  24. Possible other uses? M. Calviani - Design and challenges for the SHIP target complex • We are considering a 500 kW (3 MW pulsed) class spallation source • Possible additional uses with minor additional investments: • Neutron/photon irradiation close to the target • ~100-200 MGy/y lateral, 400 MGy/y downstream • Neutron beam(s) for different applications (i.e. neutron radiography) laterally outside of the He vessel (@500 cm or more) • …

  25. Conclusions We are looking forward for this project! M. Calviani - Design and challenges for the SHIP target complex • Target design is very challenging (but feasible!), significant R&D required on material and technical work for CFD and code optimization • Target station design needs to account the high average power (hence radioprotection and handling aspects) • Profit from CENF studies but a dedicated WG will be needed towards the DR

  26. M. Calviani - Design and challenges for the SHIP target complex BACKUP

  27. M. Calviani - Design and challenges for the SHIP target complex

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