Review of Sector th of February Tunnel Access During Powering Tests Hugues Thiesen, AB-PO

Review of Sector th of February Sector layout Tunnel QRL ARCMLITMR RR UA PM Machine Access Machine Access LHC surface access LHC surface access  Sector layout

Review of Sector th of February 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 th of February 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 th of February 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 equipments  At 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 th of February  Electrical risks The electrical equipments have to be conform at the 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 th of February  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 th of February  If the equipments are not conform? Grounding  Always mandatory Electrical Protection IP2X  Fencing + flashing lights  B0V/H0V Electrical Hazards

Review of Sector th of February Cryogenic Hazards  Cryogenic risks Asphyxia  Opening of the safety valve  Rupture of a cryogenic pipe Cold burn  Opening of the safety valve  Rupture of a cryogenic pipe Explosion  Rupture 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 tests  Risk of quench -> opening of the safety valve and/or rupture of the cryogenic pipe (depend on the current in the circuit)

Review of Sector th of February 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 th of February 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 th of February 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 ARCMLITMR RR UA PM Machine Access Machine Access LHC surface access LHC surface access

Review of Sector th of February Conclusion  Hazards in the tunnel Radiation hazards  Do not depend of the powering tests but only of the area status  Risks managed by the access system  Access is forbidden when the machine is closed Electrical hazards  Do not depend on the current level  The electrical equipments in the tunnel have to be conform at the 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 th of February Conclusion  Hazards in the tunnel Cryogenic hazards (< 1kA)  No additional risks if the current is less than 1kA  Restricted 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