LH2 Safety IssuesO2/LH2 separationNo Ignition sources near LH2Adequate ventilationAffects:Windows: absorbers and vacuumPrimary and secondary vacuum volumesSupport structure absorber/focussing coilInstrumentation (experiment and monitors)Cryogenic operationLaboratory area Cooling concerns:Minimizing window thickness/no. of windowsUniform heat maintainance of LH2FNAL LH2 Safety PanelWes Smart (chair)Jim KilmerJim PriestDel Allspach (consultant)

Catagories for FNAL LH2 Mucool Safety ReviewCivil constructionAbsorber windows Vacuum vessel windowsSafety controls systemsElectrical safety of hydrogen areas

Safety Codes and Standards for FNAL Mucool LH2 SystemFERMILAB STANDARDS (FESHM)Guidelines for the Design, Review and Approval of Liquid Cryogenic TargetsLiquid Hydrogen System Guidelines Storage and Use of Flammable GasesCryogenic System ReviewOxygen Deficiency Hazards OtherPressure Vessels, Dewars, Electrical, etc.

NATIONAL CODES ASME Code National Electric Code National Fire Protection Association Code Compressed Gas of America Standard ISA Application of Safety Instrumented Systems

FNAL Safety Requirements for WindowsAbsorber WindowsDesign: Internal WAMP = 25 psid FEA showing max. allowable stress < 0.25 UTS (this is waived by meeting the performance tests below) Material certification Window engineering/design drawing

Tests:Room temperature tests per UG-100 of the ASME code and room temp. burst test.Liquid nitrogen test burst test per UG-101 of the ASME code

Note: The LH2 circuit safety relief system includes 2 valves with a 10psid set point. In addition, a PLC-controlled vent valve will be installed

FNAL Safety Requirements for Windows (2)Vacuum WindowsAssumption: Design assumes that the beampipe attaches to absorber vacuum windows, therefore vacuum exists on both sides of the windowsDesign:Internal WAMP = 25 psidExternal MAWP = 15 psidFEA showing maximum allowable stress is

FNAL Safety Requirements for ControlsSafety Interlocks (Quadlog PLC) and Controls (Apacs)Functions:Control operations of the LH2 systemSafety interlocks for the LH2 system Safety actions in the case where flammable gas or ODH conditions are detected

System design:

Design requires knowledge of equipment value in the experimental hallAn estimate of failuer severity and frequency will be made as well as the consequences to personnel and equipmentThe overall risk will be evaluated to determine a Safety Integrity Level (SIL).The SIL will determine the safety controls architecture (level of redundancy required) per ANSI/ISA-84.01, Application of Safety Instrumented Systems for the Process Industries

Instrumentation SafetyTemperature/density uniformity inside LH2Safety instrumention inside vacuum areaDetectors for cooling measurements

Safety Issues:

1. Limits the amount of energy/(area or vol) 2. Physical size of the signal feedthroughs3. Distance away from target (e.g. VLPC readouts)4. Seals from signals to electronics:wiresfiberstubes