CMS consolidation activities of detector cooling system Detector cooling project P. Tropea

Contents Overview of the CMS detector cooling systems Water circuit consolidation works Fluorocarbon circuit consolidation works Pending issues for next shut down Operation organization Conclusions

25 March 2009P. Tropea The CMS detector cooling systems Two main groups of detector cooling systems: water (mixed or demineralized) and fluorocarbon (monophase C6F14) 1.Water: Yoke, Endcap, Muons, Ecal, Bus-Bars, Racks Water circuits are under the responsibility of EN/CV up to the USC55 cavern, CMS takes care of the operation, fine tuning and maintenance of the equipments in UXC55 2.Fluorocarbon: Silicon Strip Tracker, Pixels, Silicon Strip Thermal Screen, Preshower Fluorocarbon circuits are under the responsibility of EN/CV/DC, for Silicon Strip and Pixels a formal handover is being organized after the refurbishment program performed by CMS during this shutdown

25 March 2009P. Tropea Consolidation works on water circuits Leak search on RE circuits (RPC Endcaps) Pressure gauge to be tuned on laser-room circuit Vibration problems on Yoke/Barrel circuit (new flow restrictors) New T sensors installed (monitoring) New projects Totem/Castor cooling skids (designed, built and commissioned by EN/CV), maintained by CMS. Preliminary study on extended SCX5 cooling circuit (from 500kW to 750kW)

25 March 2009P. Tropea Consolidation on fluorocarbon circuits Thermal Screen: during shut down EN/CV/DC commissioned the two plants in stand-alone (purge and drain systems improved). Tests with the screens on to be performed, leak search to be done on the cooling plant Preshower: two cooling plants commissioned in stand-alone (EN/CV/DC). Detector installed, first cooling loops on since Monday. Purge and drain systems improved, cooling pipes cleaned Silicon Strip & Pixels: Refurbishment project lead by S. Moccia (CMS), including the full revamping of the distribution systems (manifolds, valves, connections), the improvement of the air purge system, the full leak search/repair program on the Tracker cooling loops, the new monitoring Chiller: By-pass installed on the compressors circuits, to allow smoother regulation for different heat loads (EN/CV/DC) PLC code: full revamping done to have a standard code as for the other systems operated by EN/CV/DC (EN/CV/DC)

25 March 2009P. Tropea What’s going on? (Fluorocarbon) PLC program: a document containing the CMS operation requirements has been sent to EN/CV/DC for discussion (EDMS ). Pending issues:EDMS The available levels of access (expert user mode, including non-standard operation access for commissioning purposes) Monitoring of alarms and alarm thresholds Handover of Silicon Strip and Pixels plant: the Pixels plant has been inspected and EN/CV/DC has taken the release to organize the commissioning. The same type of inspection shall be organized for Silicon Strip plants in the coming months Commissioning: all plants shall be commissioned in stand-alone, then with the detector on. This activity in on the critical path of CMS restart in 2009 and expert availability would be mandatory to shorten the process. A detailed planning and clear procedures for this phase shall be agreed as soon as possible with EN/CV/DC, having addressed the above mentioned pending issues.

25 March 2009P. Tropea What has not been addressed…. plans for 2010 consolidation? (Fluorocarbon) Some issues will be pending after the refurbishment, due to the dramatic changes in the system layout after the heat exchanger failures in 2007/2008: The full performance operation of the C6F14 cooling plants, as per the following table: The full power operation test for the main chiller The nominal operation conditions for the safety chillers of Preshower and Thermal Screen plants

25 March 2009P. Tropea Operation organization (1) For each CMS cooling system: 1) User reference person 2) CMS cooling expert responsible (team of 4 people) These people participate to the CMS cooling meetings, where needs for the operation and improvements of the cooling systems (set point changes, additional monitoring, etc. ) are discussed. The CMS cooling coordinator is in charge to collect and evaluate those requirements and ask for any intervention/modification on the cooling systems Get a reasonable and organized set of requests to EN/CV Avoid duplicates of calls Monitor the system performances better to organize future consolidation works

25 March 2009P. Tropea Operation organization 2 Difficulties remarked during 2008 operation -Communication: to be improved in both directions, use of logbooks to be activated -Fluids: increasing leak rates on running systems, storage and filling methods, data logging -Availability of spare parts, tools, etc. at P5 -Monitoring of the systems Needs for a smooth operation in Support for fine tuning with detector on (in particular on fluorocarbon circuits, for which all alarm levels and set points other than T and p cannot be modified by CMS) -Interventions of experts within 1 h during the day (8.30/17.30, as specified in the M&O agreement) -Stand-by duty service outside working hours (as in M&O agreement)

Conclusions Water circuits are in general in good shape Fluorocarbon circuits are being finalized: the handover to EN/CV/DC is being discussed and organized Commissioning of fluorocarbon plants is the most critical activity for CMS cooling in the next months Maintenance & Operation agreements shall be reviewed before the end of commissioning, as to guarantee a smooth start of the operation phase