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Tunnel Access During Powering Tests. Hugues Thiesen, AB-PO. QRL. Tunnel. IT. ML. ARC. MR. RR. PM. LHC surface access. UA. PM. LHC surface access. Machine Access. Machine Access. Sector layout. Sector layout. Hazards in the tunnel. Different Hazards Radiation Beam - PowerPoint PPT Presentation
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Review of Sector 45 - 28th of February 2008 1
Tunnel Access During Powering Tests
Hugues Thiesen, AB-PO
Review of Sector 45 - 28th of February 2008 2
Sector layout
Tunnel
QRL
ARCMLIT MR
RRUAPM PM
Mac
hine
Acc
ess
Mac
hine
Acc
ess
LHC surfaceaccess
LHC surfaceaccess
Sector layout
Review of Sector 45 - 28th of February 2008 3
Hazards in the tunnel
Different Hazards Radiation
Beam RF system
Electricity PCs QHPSs Instrumentation DFBs and theirs proximity equipments Cryo magnets
Cryogenic DFBs Cryo magnets QRL
Review of Sector 45 - 28th of February 2008 4
Radiation Hazards
Radiation risks Irradiation (beam or RF system)
Alpha, beta, etc.. Depend only of the area status, not of the powering tests
RB injection current is 760A (< 1kA) Access
No access when the sector is closed Control of the access
LHC access system (Doors and EIS)
NO ACCESS IN THE AREA WHEN IT IS CLOSED
Review of Sector 45 - 28th of February 2008 5
Electrical Hazards
Electrical risks Electrocution or burn
By touching a metallic part (active or not active)By an electrical arc (initiated by a metallic tool)
Do not depend of the current but only of the conformity of the equipmentsAt 350A the output voltage of the RB could be 160V
The electrical risks DO NOT depend on the current but only of the electrical conformity of the
equipments
Review of Sector 45 - 28th of February 2008 6
Electrical risks The electrical equipments have to be conform at the 15-100 standard (code C1)
Metallic parts have to be correctly grounded (DFB, cryo magnets, etc..)
Active parts have to be protected again direct contacts (IP2X)
Electrical Hazards
Review of Sector 45 - 28th of February 2008 7
Electrical risks Electrical inspection realized by AT/AS3 (Guy Salomon)
Electrical Hazards
The group/department must request the inspection after the installation and before the powering tests
The group/department is responsible of the conformity of its equipments
Review of Sector 45 - 28th of February 2008 8
If the equipments are not conform? Grounding
Always mandatory Electrical Protection IP2X
Fencing + flashing lightsB0V/H0V
Electrical Hazards
Review of Sector 45 - 28th of February 2008 9
Cryogenic Hazards
Cryogenic risks Asphyxia
Opening of the safety valveRupture of a cryogenic pipe
Cold burnOpening of the safety valveRupture of a cryogenic pipe
ExplosionRupture of a cryogenic pipe
Cryogenic risks vs Powering tests No powering tests
Access in the tunnel is restricted when the cool down is finished (see Serge Claudet presentation “Safety during HC” 18 October 2007)
Powering testsRisk of quench -> opening of the safety valve and/or rupture of the
cryogenic pipe (depend on the current in the circuit)
Review of Sector 45 - 28th of February 2008 10
Cryogenic Hazards
Powering tests of the corrector magnets (60A to 600A circuits) The energy stored in the magnet is not enough to created additional risks
(has to be confirmed by MPP and AT-ACR) Access in the tunnel is restricted
Powering tests of the main magnets (MB, MQ, IPD, IPQ and IT) The magnets do not quench below 1 kA (has to be confirmed by MPP) Access in the tunnel is restricted if the current is below 1kA above 1 kA ?
Review of Sector 45 - 28th of February 2008 11
Cryogenic Hazards
Powering tests of the main magnets above 1kA Limited asphyxia risk beyond 2 m (has to be confirmed by MPP/AT-ACR)
Limited Cold burn risk beyond 2 m (has to be confirmed by MPP/AT-ACR)
Limited explosion risk beyond the half sector (has to be confirmed by MPP/AT-ACR)
Review of Sector 45 - 28th of February 2008 12
Cryogenic Hazards
Powering tests of the main magnets above 1kA
IPD.L, IPQ.L (arc magnets included) or IT.L => no access in the left part of the sector (C1L to C34L) IPD.R, IPQ.R (arc magnets included) or IT.R => no access in the left part of the sector (C1R to C34R) MB, MQD or MQF => no access in the tunnel
QRL
ARCMLIT MR
RRUAPM PM
Mac
hine
Acc
ess
Mac
hine
Acc
ess
LHC surfaceaccess
LHC surfaceaccess
Review of Sector 45 - 28th of February 2008 13
Conclusion
Hazards in the tunnel Radiation hazards
Do not depend of the powering tests but only of the area statusRisks managed by the access systemAccess is forbidden when the machine is closed
Electrical hazardsDo not depend on the current levelThe electrical equipments in the tunnel have to be conform at the 15-100 standard (grounding, direct contacts protection, etc…) If the equipments are not IP2X, compensatory measures have to put in place
Fencing + flashing light or electrical screen Habilitation B0V/H0V
Access is restricted access
Review of Sector 45 - 28th of February 2008 14
Conclusion
Hazards in the tunnel Cryogenic hazards (< 1kA)
No additional risks if the current is less than 1kARestricted Access
Cryogenic hazards (> 1kA)Forbidden Access
IPD.L, IPQ.L (arc magnets included) or IT.L => not access in the left part. IPD.R, IPQ.R (arc magnets included) or IT.R => not access in the left part. MB, MQD or MQF => not access in the tunnel
Have to be confirmed by AT
General conditions Access must be ONLY given by the CCC for the tests team
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