LHC Performance Workshop - Chamonix 2010

Session

Session 3 - Optimise Interventions and Recovery from Collateral Damages on Cold Sectors

S03

26 Jan 2010, 08:30

Chamonix

Presentation materials

Paper

PS_3_0_Summary.docx

PS_3_0_Summary.pdf

13. Can we optimise the cleanup process further?

Vincent Baglin

26/01/2010, 08:30

Following the sector 3-4 incident, about 5 km of beam vacuum system have been spoiled with soot, metallic and super insulation debris. During four months, several teams have intensively worked to recover the beam vacuum system. The presentation will address the successive sequences of this activity in terms of preparation, execution and control. Steps where time was lost and the possible...

14. What is the MCI in case of a “beam driven” failure of a magnet enclosure

Rob Van Weelderen

26/01/2010, 08:55

Calculation hypothesis Short-term versus long-term pressure effects Arc and stand-alone magnets Worst case, uncertainty

15. Means to limit the collateral damages in the beam vacuum chamber

Miguel Jimenez

26/01/2010, 09:20

The incident in the sector 3-4 has pointed out the need to limit whenever possible the propagation of the contamination by soot, MLI and other debris to an entire arc. Indeed, the subsequent endoscopic inspection and cleaning imply about 6 months of shutdown and requires opening the interconnections every 200 m. Following a brief review of the 3-4 incident, the impact of a similar incident at...

16. What repair activity can be done today on a locally warmed-up sub-sector?

Paul Cruikshank

26/01/2010, 10:15

Interventions to repair components inside LHC cryostats can only be performed with the system at room temperature. The architecture of the cryogenic and vacuum system permits local warm-up of the 2.8 km arc cryostat. The method, prerequisites, means, constraints, risks and time to locally warm-up a sub-sector are compared to a complete arc warm-up, including the steps to get back to 1.9 K...

17. Can we change a magnet without warming-up a full arc?

Serge Claudet

26/01/2010, 10:40

What can be done today? Time required, risk to cryogenic lines and beam vacuum (back-streaming of gas) Can the cryogenic distribution be adapted to allow it? Safety, in particular during welding processes of lines What has to be retested after such an intervention?

18. Decoupling of adjacent cryogenic sectors

Gerard Ferlin

26/01/2010, 11:05

The LHC sectors are coupled two by two via interconnection boxes allowing cryoplant cooling redundancy and efficient stand-by or low-beam-intensity operation. The present LHC cryogenic sectorization allows to performed mechanical interventions on the magnet cold-mass circuit of a sector, like diode or interconnection splice repairs while the adjacent sector remain in nominal cryogenic...