SOME CEDAR NEWS Lau Gatignon / EN-MEF TD meeting 12/07/2011  Summary of HAZOP and Zoning meeting  Forthcoming CEDAR related work at CERN

HAZOP and Zoning meeting 21/06/11 Intense meeting (~ 5 hours) with J.Gulley + A.Sharma + various representatives from NA62 and the CEDAR team The CEDAR counter and its environment were presented and the various safety aspects and requirements discussed Presentations of the gas system were made and a few minor modifications were suggested Four main operational procedures “nodes” were identified and discussed in a systematic approach, called HAZOP. The conclusions are noted in HAZOP record sheets. I will not go through the sheets, but concentrate on the main items!! The sheets are attached so that you can consult them. Finally we defined the zoning of the CEDAR and related zones. In total 8 zones were listed. L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 2

General CEDAR issues The CEDAR is “connected” to the beam vacuum with thin Al windows (150 and 200 microns thick), to be tested with appropriate safety factors – contact P.M. Santos Silva / HSE A buffer volume (~5 m3) will be installed close to the CEDAR to serve as buffer volume in case of window rupture The diaphragm motor and end switches are inside a Zone 2 and must therefore be replaced by ATEX rated ones The insulating material must be replaced by non-flammable one, even if this is less optimal in terms of insulation L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 3

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The gas system A detailed presentation of the gas system was made by Stefan Haider and Roberto Guida Before filling with H2, the CEDAR is first emptied via an exhaust line to the outside. The beam line and blue tank must be evacuated beforehand There is a possibility to flush the counter and gas system with N2, e.g. in case of interventions Apart from computer-controlled valves there are also manual valves, the interventions on which must be logged by computer The four main processes are: Purging with N2, Filling with H2, Pressure scan and Emptying the counter. These were analysed in a HAZOP procedure L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 8

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Some HAZOP conclusions Purging of the lines: A watchdog will monitor that the computer is alive. If not, all activity will be stopped. The CEDAR will in that case not be emptied Emptying the counter: empty the beam line first Hydrogen filling: similar to the first node Pressure scan: from high to low pressure, as this has smaller impact on the temperature of the gas in the detector The HAZOP record sheets will be put on EDMS There is no need for an “emergency emptying” procedure L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 10

Zoning All ATEX Zoning must be recorded by the FGSO (A.Sharma) The alignment motors at the downstream end are not in a zone and need not to be ATEX rated The 8 zones are described in the following slides. It was considered to avoid zone 7 by having directly welded long pipes attached to the CEDAR but this was finally considered impractical L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 11

The zones (1-4) ZoneDescriptionComments 1The gas storage buildingWhere the H2 bottles are stored. Detection equipment to be suitable for H2 and installed by F.Schmitt / GS-ASE 2The mixing zone in B918State of the roof to be checked. Only the H2 rack is zone 2 (if closed, if not also a 1 meter perimeter) 3The underground gas systemThe zone 2 is confined to the (closed) rack itself, therefore the electronics can be close to the rack The gas lines to the CEDAR can run over the floor but they must be protected 4Quartz windowsOnly the central part of the N2 enclosure close to the quartz windows is “Zone 2 of Negligible Extent”. The PMTs are in the safety area. Gas detection in the N2! The N2 flow is interlocked with the power L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 12

The Zones (5-8) ZoneDescriptionComments 5Feedthroughs and safety relief valve Diaphragm motor falls in a zone 2 and must be ATEX 6Inside H2 volumeATEX endswitches for the diaphragm 7The gas connections belowThese form a Zone 2 with ±0.5 m dimension. Boundaries must be clearly marked. No ignition sources here! 8Exhaust from vent linesWill be ATEX 1 or 2 zone. At a safe place outside (tbd). L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 13

Other CEDAR activities at CERN The nose will be cut at CERN following detailed instructions from UK groups The hydro-formed Al windows will be made and tested at CERN (by V.de Jesus) in close contact with the HSE unit The H2 infrastructure (vent lines) will be organised by EN/MEF (with in particular the help from M.Wilhelmsson for the gas infrastructure plus gas + exhaust lines) We will look into the possibility to produce a spare Cedar-W The aim is still to have the Cedar operational for the 2012 technical run, but this is ambitious. A test run (based on a standard Cedar)in the H6 beam line is planned for October L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 14

Spare slides (HAZOP record sheets) L.Gatignon, CEDAR HAZOP & Zoning, NA62-TD meeting 15

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