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S. EVRARD – thanks to J-L Grenard and A. Pardons

XTAX repair & T9 target modification. S. EVRARD – thanks to J-L Grenard and A. Pardons. Content. Challenging situation Optimisation steps Sequence of actions Collective & individual dose Lessons learnt. XTAX repair: a challenging situation. Failure of motors

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S. EVRARD – thanks to J-L Grenard and A. Pardons

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  1. XTAX repair & T9 target modification S. EVRARD – thanks to J-L Grenard and A. Pardons

  2. Content • Challenging situation • Optimisation steps • Sequence of actions • Collective & individual dose • Lessons learnt S. Evrard, XTAX repair & T9 target modification

  3. XTAX repair: a challenging situation • Failure of motors • The XTAX are made of massive blocks put on motorized tables that can move up/down. • They act as primary beam dump or beam aperture limiter. • High radiation environment • The TAX blocks intercept about 10E19 protons/year  about 6 mSv/h outside the shielding and probably 30 to 40 mSv/h at the blocks and even higher near the beam impact point S. Evrard, XTAX repair & T9 target modification

  4. XTAX repair: Optimisation steps • PR537 remote control • Increase PR537 lifting height • Lateral shielding stays in place • Bunker for mechanical work • 2 level bunker • Shielding of 100 mm thick steel plate • Pre-defined holes for reducing exposure to hot elements S. Evrard, XTAX repair & T9 target modification

  5. XTAX repair: Sequence of actions 1 Bunker assembly 2 service disconnection 3 shielding roof removal 4 table handling S. Evrard, XTAX repair & T9 target modification

  6. XTAX repair: Sequence of actions 5 springremoval 6 oldmotorremoval 7 new motor installation 8 table back handling S. Evrard, XTAX repair & T9 target modification

  7. XTAX repair: on-line monitoring • The RP supervisor follows in real time more than one person and can react to any alarm • Especially useful during high dose rate job (like proximity work, service connection,…). Graphical interface On-line cumulative dose and dose rate monitoring S. Evrard, XTAX repair & T9 target modification

  8. XTAX repair: collective & individual dose Dose estimates Remote handling • Motor repair procedure very well studied and optimised  real dose <<<< estimates • Proximity intervention lessoptimised  real doses = estimates • Ways of improvement : use of robot, cold cell or new connection design • Individual dose: self-commitment 600 uSv respected Shielding S. Evrard, XTAX repair & T9 target modification

  9. T9 target modification: a challenging situation • T9 target station • Inner part of copper blocks : 1 Sv/h • T9: transformation to HiRadMat beam dump: 1. Remove target, all collimators & monitor 2. Replace upstream collimator with new collimator 3. Replace other items with TED-type beam dump 4. Close shielding and complete HRM beam dump ν-production target Copper downstream collimator blocks Steel upstream collimator Downstream monitor S. Evrard, XTAX repair & T9 target modification

  10. T9 target modification:Optimisation steps • Challenges: • Each block (2.7t) is not fitted with lifting point and has hot outer surface • Axis of 2 blocks is outside range of overhead crane • Items not designed for remote handling(installed with forklift on 1993, 4 threaded holes per block) • Solutions: • Lifting & shielding plates fixed manually on copper blocks • Custom-made lifting beam takes 2 blocks at the time • Shielding in place for all manual interventions • Extensive tests on mock-up (tools, training, camera) S. Evrard, XTAX repair & T9 target modification

  11. T9 target modification: sequence of actions Moving upper blocks with fixed lifting plates Sarcophagus with containers ready Blocks in temporary storage location Dismantling work took ~10 days, collective dose of ~1.2mSv for Copper block removal Fixing plates on lower blocks Separating blocks 21 Placing block in container Lifting test before closing roof S. Evrard, XTAX repair & T9 target modification

  12. T9 target modification: collective dose • Optimisation, tools, training brings WANF dismantling from est. 210 man.mSv to 60 man.mSv. T9 target modification amounted to 2.7 man.mSv. • The main contributions are from low dose rate but long-lasting activities, impossible to do remotely (by design) or carried out by less experienced personnel. WANF dismantling S. Evrard, XTAX repair & T9 target modification

  13. lessonslearnt • Design of High Radiation Areas • Take into account dismantling needs as from the design stage • Include dedicated areas in TA for remote handling operation, RP supervision (preparation, monitoring,…) • Equip underground areas with most recent technology means (optical fibers, cable network for cameras, Wi-Fi network) • Remote controlled crane with positioning system S. Evrard, XTAX repair & T9 target modification

  14. lessonslearnt • Intervention in High Radiation Areas: • preparation and organization are essential • Training on mock-up • Planning and resources management • Systematic dose rate check (remote device or RP technician) before intervention • On-line & daily dose monitoring • QAP S. Evrard, XTAX repair & T9 target modification

  15. lessonslearnt • Repair& dismantling procedure: some valuable concepts • Keep inaccessible the most activated parts • Avoid time-consuming activities • Mitigate time-consuming activities by shielding • Standardize repetitive actions • Enhanced personnel safety by camera monitoring • Improve reliability of key resources (overhead crane) S. Evrard, XTAX repair & T9 target modification

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