the sector 3-4 incident at the lhc: fault tree and corrective measures ph. lebrun risk analysis...
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The Sector 3-4 incident at the LHC:The Sector 3-4 incident at the LHC:fault tree and corrective measuresfault tree and corrective measures
Ph. Lebrun
Risk Analysis Review CommitteeCERN, 5 March 2009
Absence of soldering
Resistance 200 nOhm Bad contact with stabilizer
No sensitive detection on bus bar
Thermal runaway
Meltdown, open circuit
Power converter fast discharge
Electrical arc
Fault tree [1/3]Fault tree [1/3]
Electro-thermal model
Observed on
magnet
Fault tree [2/3]Fault tree [2/3]
Electrical arc
Beam pipe perforation
He vessel perforation Soot
He discharge in insulation vacuum
Contamination by soot
Inadequate sizing of relief devices
(MCI)
Pressurization of vacuum enclosures
Mechanical damage to MLI
Contamination by MLI
ODH in tunnel
Blast
Trip AUG
Loss of beam vacuum
Break vent door
Fault tree [3/3]Fault tree [3/3]
Pressurization of vacuum enclosures
Pressure forces on vacuum barriers
Plastic deformation of shells
Buckling of bellows
Rupture of supports and ground anchors
Displacement of magnets
Mechanical damage to interconnects
Secondary electrical arcs
Damage to tunnel floor
Used to estimate max pressure
reached
Absence of soldering
Resistance 200 nOhm Bad contact with stabilizer
No sensitive detection on bus bar
Thermal runaway
Meltdown, open circuit
Power converter fast discharge
Electrical arc
Corrective measures [1/3]Corrective measures [1/3]
Measurement of joint resistance (calorimetry & electrical)
Additional quench detection on bus
bars
Absence of soldering
Resistance 200 nOhm Bad contact with stabilizer
No sensitive detection on bus bar
Thermal runaway
Meltdown, open circuit
Power converter fast discharge
Electrical arc
Corrective measures [1/3]Corrective measures [1/3]
Measurement of joint resistance (calorimetry & electrical)
Additional quench detection on bus
bars
Mechanical clamping of joints?
Corrective measures [2/3]Corrective measures [2/3]
Electrical arc
Beam pipe perforation
He vessel perforation Soot
He discharge in insulation vacuum
Contamination by soot
Inadequate sizing of relief devices
(MCI)
Pressurization of vacuum enclosures
Mechanical damage to MLI
Contamination by MLI
ODH in tunnel
Blast
Trip AUG
Loss of beam vacuum
Break vent door
Revised MCINew relief devices
Harden AUG
Harden vent door
Corrective measures [2/3]Corrective measures [2/3]
Electrical arc
Beam pipe perforation
He vessel perforation Soot
He discharge in insulation vacuum
Contamination by soot
Inadequate sizing of relief devices
(MCI)
Pressurization of vacuum enclosures
Mechanical damage to MLI
Contamination by MLI
ODH in tunnel
Blast
Trip AUG
Loss of beam vacuum
Break vent door
Revised MCINew relief devices
Harden AUG
Harden vent door
Trigger q-valves?
Fire q-heaters?
Corrective measures [3/3]Corrective measures [3/3]
Pressurization of vacuum enclosures
Pressure forces on vacuum barriers
Plastic deformation of shells
Buckling of bellows
Rupture of supports and ground anchors
Displacement of magnets
Mechanical damage to interconnects
Secondary electrical arcs
Damage to tunnel floor
Reinforce ground anchors