EN-CV interventions during YETS

Maintenance

Cooling: yearly maintenance 3 weeks of stop for the SF, SU, UW Mechanical cleaning of the cooling towers Mechanical and electrical maintenance Bugs fixing SF UW SU

Ventilation: yearly maintenance No stop but redundancy affected during the maintenance. Intervention mostly on the surface. Tunnel air handling units Accessible areas (US, UA) air handling units Experimental cavern UX air handling units Yearly maintenance of the 174 underground units should be finished by TS3 (corrective actions could be needed during YETS)

Planning for EN-CV maintenance - tbc LHC pointsStopRestart Point 114th of December 1515th of January 16 Point 18tbd Point 21st of February 1619th of February 16 Point 322th of February 1626th of February 16 Point 411th of January 1629th of January 16 Point 514th of December 1515th of January 16 Point 61st of February 1619th of February 16 Point 722th of February 1626th of February 16 Point 811th of January 1629th of January 16

Additional works

Point 1 – additional works ALFA cooled cables in RR13 and RR17 Installation of by-pass on the ATLAS US15 mixed water circuit Qualification of the compressed air vessel in SH1 + installation of valve. (stop needed) SF1: dismantle and repair cooling towers silencers Modification of the firefighting water circuit in SUX1 USA15: replacement of the ED pumps, filling circuits and installation of additional valve.

Point 18 – additional works Full replacement of the cryo underground cooling plant in PM18 4 weeks of stop Tbc by the Consolidation for the budget Tbc by the cryo and MEF for the time window

Point 2 – additional works SX2: modification of the pipework to install an Eletta for TE/EPC Replacement of the leaking valve in point 3 requesting to stop and empty the sector 2-3 Work in UW25 to replace flexible sleeves and modify pipework Replacement of the raw water blocked valve in UL26 Replacement of the ventilation unit for ITS in SX2 Preparatory works for the replacement of the SR2 ventilation system (foreseen during EYETS). Intervention in the false floor: lockout required.

Point 3 – additional works PM32 consolidation phase two Tbc by the Consolidation (budget) 6 weeks of work. Most of it in surface. Preparatory works for the replacement of the SR3 ventilation system (foreseen during EYETS). Intervention in the false floor: lockout required

Point 4 – additional works SU4 migration of the cooling control system → Unicos 4 weeks of stop (+maintenance) SH 4 migration of the ventilation control system → Unicos (3 weeks) SHM 4 migration of the ventilation control system → Unicos (3 weeks)

Point 5 – additional works SUX5 migration of the cooling control system → Unicos (tbc by CMS) 3 weeks of stop (+maintenance) Mechanical maintenance on the ventilation in RR53 and RR57 Modifications and repair of point 5 raw water in SD5. Raw water stopped and compensatory measure to discuss. Maintenance of Totem cooling plants in R532 and R571. Preparatory works for the replacement of the SR5 ventilation system (foreseen during EYETS). Intervention in the false floor: lockout required Fixed non-conformities in water connections on the cooled cables in RR53

Point 6 – additional works SH 6 migration of the ventilation control system → Unicos (3 weeks) SHM 6 migration of the ventilation control system → Unicos (3 weeks) Work in UW65 to replace flexible sleeves and modify pipework Preparatory works for the replacement of the SR6 ventilation system (foreseen during EYETS). Intervention in the false floor: lockout required

Point 7 – additional works Preparatory works for the replacement of the SR7 ventilation system (foreseen during EYETS). Intervention in the false floor: lockout required

Point 8 – additional works Cooling test plant for future datacenter Modification for a backup of the LHCb control room racks Modification of the UAPE-831 and 832 installation of VSD. Point bas: replacement of the pumps. UW85 : replacement of the flexibles sleeves and additional support SH 8 migration of the ventilation control system → Unicos (3 weeks) SHM 8 migration of the ventilation control system → Unicos (3 weeks) Work in UW85 to replace flexible sleeves and modify pipework