Follow up meeting Protecting the experimental caverns and personnel from a "sector 34 like" incident: work planned in the LHC tunnel Prepared by M GASTAL with contributions from EN-MEF: David HAY (EAM team) CMS: Christoph SCHAEFER (CMS Glimos), Nicolas Siegrist (Ansys simulations), Teresa RODRIGO Mar SOBRON Joao ANTUNES (Alignment), Nebojsa SMILJKOVIC & Jean BOS (CMS design office) TE-VSC: Nicolas ZELKO, Patrick LEPEULE EN-MME: Jean-Pierre BRACHET Pascal MESENGE Gilles FAVRE (Central workshop), and Giuseppe FOFFANO EN-CV: Antonio Romanazzi (computations in fluid dynamics) 31/08/2009 1 Agenda: 1- Modifications in the CMS TAS regions 2- Sealing all remaining openings 3- Pressure resistant doors and ODH sensors [email protected]
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Follow up meeting Protecting the experimental caverns and personnel from a "sector 34 like" incident: work planned in the LHC tunnel
Prepared by M GASTAL with contributions from EN-MEF: David HAY (EAM team)CMS: Christoph SCHAEFER (CMS Glimos), Nicolas Siegrist (Ansys simulations),
Teresa RODRIGO Mar SOBRON Joao ANTUNES (Alignment),Nebojsa SMILJKOVIC & Jean BOS (CMS design office)
TE-VSC: Nicolas ZELKO, Patrick LEPEULEEN-MME: Jean-Pierre BRACHET Pascal MESENGE Gilles FAVRE (Central
workshop), and Giuseppe FOFFANOEN-CV: Antonio Romanazzi (computations in fluid dynamics)
31/08/2009 1
Agenda:
1- Modifications in the CMS TAS regions2- Sealing all remaining openings3- Pressure resistant doors and ODH sensors
→ Goals to achieve: → Restrict the TAS movements in Z during alignment→ Prevent longitudinal TAS movement in case of an September 19th type
of incident→ Prevent a flow of He from the tunnel to propagate into the UXC55→ Avoid having to stay in the vicinity of the TAS once it is activated
→ E.g. alignment and removal operations
→ Limitations:→ Stay clear of vacuum equipment→ Keep a fixed point on tunnel side for TAS bake-out purposes→ Keep the air flow around TAS for cooling purposes→ Allow for a removal of the TAS during the phase 1 upgrade with
→Assuming an over pressure of 110mb in the tunnel, each Z-stop will experience a maximum deflexion of 0.11mm
→Stability of the TAS is insured by using 2 Z-stops on opposite sides of beam pipe→Installation scheduled to start on 02/09→Manufactured in B530 workshop
How will the TAS behave in the CMS magnetic field?
→ Both TASs have been instrumented and monitored while ramping up the B field from 0T to 3.8T
Material: 0.5mm thick Stainless steelManufactured in central workshopLeaves a 2cm gap for air flowTrigger pressure for closure is 8mbarWhen exposed to 110mbar
Max deformation = 9.10-6 mmGuided by existing structures
How to cool down the TAS?→ FLUKA simulations by S Muller give consistent values
→ The TAS equilibrium temperature in the absence of air flow was calculated to be ~ 100deg C. The temperature limit for the TAS vacuum chamber being set to 75 deg C, it would be reached within 2.5 month.
→ Conclusions and implementation→ Active air cooling using the UXC55 nominal overpressure should be sufficient to keep the
temperature of the TAS in a range acceptable for TE-VSC throughout its life time.→ The temperature of the TAS will be monitored at all times by CMS DSS using
thermocouples already installed by TE-VSC→ The water cooling pipe installed on the tunnel face of the TAS has been tested up to
10Bars and would be available if needed→ A first section of water pipes will be installed by EN-CV in the vicinity of both TASs
shortly as an extra precaution. This would allow installing active water cooling without having to get near a potentially hot TAS
→ Deadline set by start of powering tests phase 2 in sector 56: 14/09 → Membranes are both manufactured and installed→ Z-stops are being mounted on mock-up→ Installation scheduled for Tuesday 01/09
→ A dedicated EDMS page will be set up by 04/09; all relevant documents (text, pictures, simulations, models) will be stored at this location
→Holes between the CSF and the FIN have been closed→The resulting seal will withstand 110mBar→New system uses metal plates and blocks filled up with concrete