Helium spill in LHC tunnel 17/01/2013 He spill

Helium Spill Test in LHC tunnel Actual / Future situation Actual situation: Restricted work area of 3 m, centred around release point (based on scale model); Future situation?: Restricted work area of 12 m (9% of tunnel), based on scale model or Restricted work area of 80 m (45% of tunnel), based on simulations Large difference between result of studies → check with a real spill test 17/01/2013 He spill

Helium Spill Test in LHC tunnel Set-up of the spilling test Liquid helium spill of 1 kg/s Total spill per test 125 kg (= 1000 liquid liters) Ventilation flow in access mode: 18000 m3/h, about 0.7 m/s in tunnel (more tests foreseen) 1450 mm DN 200 Equip the tunnel with measurement system 25 Temperature sensors (Pt100) 25 ODH (special development of fast reacting measurement head) 6 cameras 4 air velocity sensors 2 mass balances (used for calculation of mass flow) Equipment will be placed within 100 m upstream and 200 downstream of release point 17/01/2013 He spill

Helium Spill Test in LHC tunnel Spilling test Test foreseen for first week February, in sector 4-5, left of 5, 300 meter into arc, during night time All equipment owners in the area where the spill test will find place, are asked to protect their sensitive material (electronic cards, connectors etc.) against condensation of water during the spilling test Two conditions should be fulfilled during the test Should have “reasonable” ventilation speed in the tunnel (as close as possible to nominal access conditions 0.7 m/s) > 0.2 m/s Over pressure in CMS cavern so no helium will enter into the CMS cavern 17/01/2013 He spill

Test ventilation speed in sector 4-5 under test conditions Close shielding between UL46 and UJ46 Close door in RB46 Close door between UA47 and RA47 Once the tunnel in this situation, a ventilation speed measurement will be made at test location. This ventilation speed can re-produced during test since we can re-create this same situation Test Wednesday evening: ventilation speed at spill point: between 0.5 m/s and 1m/s (depending on height) 17/01/2013 He spill

Test overpressure CMS cavern To close off the UXC55 cavern at least the following connections have to be closed: UXC55 from tunnel (check beam tube and survey tunnels) and cap USC55 from tunnel (closure of door betweenUSC55 and RZ54) Once these modifications have been made a check of the capability to over pressurize (ideally 20Pa) the UXC55 cavern can be made. Test Wednesday evening: overpressure of up to 31 Pa 17/01/2013 He spill

No showstopper identified up to now, so we continue the preparations: Full seize spill (500 l) at surface (check of mechanical equipment and mass flow); Installation of cabling and piping in tunnel Equipment of test stands Circulation of test procedure (at the moment being checked by Thomas Otto) Sector 4-5 will be closed during week January 27th 17/01/2013 He spill

Access P5 during test week Every test day, before test: at 5 pm: shielding walls and ventilation doors closed at P4 at 8 pm: barriers put in place at P4: RB46, UL46 P5: PM56, Q15L15, RR57 and PM54 in closed mode Patrol from P4 to RR57 Every test day, after test: Fire brigade will make ODH check Fire brigade will check conformity ODH, fire detection and alarm systems Identification of eventual damages and contact with TI (piquet intervention) Removal barriers at P4 and P5 Free access to PM54 In case of problems with ODH, fire detection or alarm system: Only removal of barrier at P4 ASE intervention between 6 and 7.30 am When problem solved, site coordination will remove barrier 17/01/2013 He spill