Preparation of the activities for the LHC Long Shutdown 2 Section Operation

LS2 Maintenance Maintenance plan must be done (3.3kV motors, Compressors, instrumentation, Charcoal, ORS, electrical cabinets, Vacuum…); All plants LHC/Atlas/Cms quid of Dryers cleaning of ORS and HP pipes (LHCA_Linde) Dedicated Maintenance for Cold Compressor cartridges, Mapag and associated instrumentation. QRL X-ray after warming up and repair if necessary Leak check of all QRL valves Line C to B/D and repair if necessary QUI/RM valve leak check and repair if necessary P4 helium guard leak & P18 VLP to be solved Helium guard: Leak test of the circuits and individual leak research on all the components (O-ring for valve shaft, O-ring for valve or instrument flanges) 2017-09-25 TE-CRG-OP_GF

LS2 Consolidation/improvement Mechanical hardware 16 Valves plugs to be exchanged on QRL_CV920 QUI U tube valves to be motorized RM R1, QUI-P2… must be made operational Switchable cooling water filter for cold boxes Electrical/instrumentation hardware Cold compressors Electrical cabinet upgrade to avoid P2 communication problems Upgrade of AMB/VFD to end cold compressors refurbishing Instrumentation to upgrade (TT cold comp, LHE level sensors TT turbines…) Controls Atlas: Migration to CPC6 Improvement of control system to increase availability (Majority voting, Alternative sensor, Safety chain upgrade…) PVSS upgrade PLC update to M580 to be ended 2017-09-25 TE-CRG-OP_GF

LS2 Consolidation not yet approved Outlet turbines TU2 & TU4 on Linde LHCA cold boxes: add sectorization valve QUI: sectorizations valves P2 and/or P8, LHCA AL: major compressor station upgrade LHCA (AL/Linde): electrical cabinet refurbishing Possible co-activities and associated issues P4 Upgrade of LHCa/b to fit with new RF cavities scheme P6 Commissioning of the re-liquefier Atlas/CMS Civil engineering to prepare HL-LHC LHC Pressure tests 2017-09-25 TE-CRG-OP_GF