1. First Considerations on CLIC Cooling System Ch. Martel, J. Inigo-Golfin TS/CV

2. Clic – Primary Water Cooling Studies underway for determination of primary cooling source –Upgrade of studies made in 2001-2002, according to Technical Note 3, –Determination of overall cooling capacity based on latest information (Carlo Wyss, meetings 13 th & 22 nd 08/2007), –Location and siting of cooling plants, –Determination of preliminary piping section for integration purposes, based on assumed data (inlet temp. ΔT, ΔP and number of circuits – secondary, tertiary, etc.). –Alternative scenarios already studied in 2001 well advanced. Different layouts (technical caverns, etc) according to technical solution chosen.

3. Clic – Secondary Water Cooling Secondary cooling (demin. water) studies underway –However basic design information is still missing for some circuits (i.e. cooling of the beam absorbers, klystrons). –Constraints on water speed in tunnel piping (vibration)? –Agreement on stabilised water requirements? –Assumption UTRB caverns are not necessary. Racks water cooled (600 kW). Tertiary circuits for beam dumps (1 MW). –Requirements so far not optimized w.r.t. piping and tunnel sections (modules cooling). –Requirements could have severe impact on sizing of access shafts, tunnels.

4. Clic – Other Services Compressed air? Discharge water system. Separation system (oil, sand)? Sprinkler or water-mist extinguishing/fire retardant systems in main linac tunnel? Idem in experimental/technical caverns?

5. Clic – HVAC Systems HVAC possible functions: Fresh air and ventilation (obligation) Overpressure control linked to radiation areas (obligation) Safety role: smoke extraction, overpressure, protected areas, fire fighting, fire protection, purge (obligation) Dehumidification Constant ambient conditions: temperature and humidity Air cooling Gas extraction Other

6. Clic – HVAC Systems HVAC criteria shall be specified for each structure: Detailed definition of the structure (fire volumes, partition, and shielding, plug on head of shaft) Required ambient conditions: temperature and humidity Radiation levels in the various areas Description of accessible and non accessible areas Heat dissipation levels in the air (when water cooling not possible) Presence of gas, which gas ? Other

7. Experimental cavern ventilation

8. Typical LHC Tunnel ventilation

9. Typical CERN LHC section Longitunal ventilation

10. New proposed tunnel section Transversal ventilation

11. - No ΔT along the tunnel - Better air cooling - Real smoke extraction - Smoke compartmentalization - Safe evacuation - Evolutive capacity Compatible with new tunnel safety requirements throughout the world

12. Clic - Conclusions Refining of requirements necessary, first version of URD should be issued in the coming months with the main sizing parameters, Compromises in the design, in view of the very large numbers involved, not to be dismissed without careful consideration.

13. Typical CE Tunnel Section

14. Integration of required pipes