1. The cryogenic system of the HIE-ISOLDE project and its related hazards for persons N. Delruelle on behalf of the TE/CRG group HIE-ISOLDE Safety Review – 05 Nov 2013

2. Outline HIE-ISOLDE Safety Review - 05 Nov 20132 ► Cryogenic system layout ► Risk matrix adopted by CERN ► Risks / Hazards identified for persons ► Summary / Conclusion

3. Cryogenic system layout HIE-ISOLDE Safety Review - 05 Nov 20133 Volume: 2*80 m 3 GHe Oper. Temper.: 300 K Oper. Pres.: [2, 14] bara Volume: 300 liters LHe Oper. Temper.: 4.6 K Oper. Pres.: 1.4 bara 1) Gas storage 2) Compressors bldg Volume: ~ 4 m 3 GHe Oper. Temper.: 300 K Oper. Pres.: [1, 15] bara 3) Cold box bldg Volume: 1000 liters LHe Oper. Temper.: 4.5 K Oper. Presur.: 1.3 bara

4. Cryogenic system layout HIE-ISOLDE Safety Review - 05 Nov 20134 4) Experimental hall Volume: 6*120 liters LHe Oper. Temp.: 4.5 K Oper. Pres.: 1.3 bara

5. Outline HIE-ISOLDE Safety Review - 05 Nov 20135 ► Cryogenic system layout ► Risk matrix adopted by CERN ► Risks / Hazards identified for persons ► Summary / Conclusion

6. CERN risk matrix HIE-ISOLDE Safety Review - 05 Nov 20136

7. Outline 7 ► Cryogenic system layout ► Risk matrix adopted by CERN ► Risks / Hazards identified for persons ► Summary / Conclusion

8. Risks/hazards for persons HIE-ISOLDE Safety Review - 05 Nov 20138 ► 1) Gas storage TagIncident/RiskLikelihoodImpactRemarkRisk mitigation 1aRupture of helium pipe (operated at 300K) by a truck. RareModerateHuge noise.Install metallic barrier to protect helium pipes. 1bRupture of gas storage vessel due to overpressure RareMajorHuge noise.Max compressors discharge P is 15 bar whilst storage vessel design P is 25 bar.

9. Risks/hazards for persons HIE-ISOLDE Safety Review - 05 Nov 20139 ► 2) Compressors building (bldg 198) TagIncident/RiskLikelihoodImpactRemarkRisk mitigation 2aRupture of helium pipe (operated at 300K) due to excessive vibration or hit by a forklift. RareMajorHuge noise. Spilling of gaseous He  O 2 deficiency. Install metallic barrier to protect helium pipes. 2bRupture of oil pipe due to excessive vibrations. PossibleModerateOil splilling on bldg floor. -Compressor station installed on a floor without wastewater discharge. -Install laser beam above compressor to detect oil clouds.

10. Risks/hazards for persons HIE-ISOLDE Safety Review - 05 Nov 201310 ► 3) Cold box building (bldg 199) TagIncident/RiskLikelihoodImpactRemarkRisk mitigation 3aRupture of cold box insulation vacuum. RareMajorSpilling of 300 L of liquid He hold in cold box  cold burns & O 2 deficiency. -Install metallic fences around cold box area. -If ODH alarm  EN/CV extraction flow is doubled (14000 m 3 /h) 3bRupture of main transfer line due to excessive thermal stresses @ 4.5K PossibleModerateSplilling of liquid He hold in transfer line. Impose use of bellows to compensate thermal contractions @ 4.5 K. 3cRupture of dewar insulation vacuum RareCatastrophicSpilling of 1000 L of liquid He hold in dewar  cold burns & O 2 deficiency. Same risk mitigation as «3a» + exhaust of safety valves outside bldg.

11. Risks/hazards for persons HIE-ISOLDE Safety Review - 05 Nov 201311 ► 4) Experimental hall & tunnel (bldg 170) TagIncident/RiskLikelihoodImpactRemarkRisk mitigation 4aRupture of jumper box insulation vacuum. RareModerateSplilling of liquid He hold in the main transfer line. -Liquid helium supply stopped if vacuum not OK. -Hall 170 is huge with respect to volume of He hold 4bRupture of transfer line (from jumper to cryo- modules) due to excessive thermal stresses @ 4.5K RareModerateSplilling of liquid He hold in the transfer line. Same risk mitigation as «4a». 4cRupture of cryo- module insulation vacuum inside the tunnel. PossibleCatastrophicSpilling of 120L of liquid He hold in reservoi  cold burns & O 2 deficiency. Same risk mitigation as «4a» + exhaust of safety valves outside tunnel

12. Outline HIE-ISOLDE Safety Review - 05 Nov 201312 ► Cryogenic system layout ► Risk matrix adopted by CERN ► Risks / Hazards identified for persons ► Summary / Conclusion

13. Summary / Conclusions HIE-ISOLDE Safety Review - 05 Nov 201313 1a; 4a; 4b 1b; 2a; 3a 2b; 3b 3c4c

14. Summary / Conclusions HIE-ISOLDE Safety Review - 05 Nov 201314 ► Major known risks have been identified; ► Some risks have been mitigated already since the design phase (e.g. design pressure and use of bellows imposed in CERN technical specifications, routing outside bldg of safety valves on liquid He); ► Some other risks can be avoided by denying access during transient modes (cool-down & warm-up of cryomodules) where pressures are higher and where thermal contractions are present; ► Finally, we have to live with some risks that cannot be mitigated during the design phase but they have to be reduced by some “special access procedures”.