MICE LH2 Absorber

1
MICE LH2 Absorber

1. Assembly
2. Safety
3. Staging
4. Instrumentation

2
Absorber Design Issues

• LH2 circulation and heat extraction
• Monitoring and instrumentation
• Window attachment
• Assembly and disassembly
• Removability
• Stabilization
• Cryogenic attachments
• Temperature stability
• Insulation of hotter/colder elements
• Prevention of O2 condensation
• Vacuum integrity
• Physical modifications and upgrades

3
LH2 Safety Issues

• O2/LH2 separation
• No Ignition sources near LH2
• Adequate ventilation
• Affects
• Windows absorbers and vacuum
• Primary and secondary vacuum volumes
• Support structure absorber/focussing coil
• Instrumentation (experiment and monitors)
• Cryogenic operation
• Laboratory area
• Cooling concerns
• Minimizing window thickness/no. of windows
• Uniform heat maintenance of LH2

4
Categories for FNAL LH2 Mucool Safety Review

1. Civil construction
2. Absorber windows
3. Vacuum vessel windows
4. Safety controls systems
5. Electrical safety of hydrogen areas

5
Safety Codes and Standards for FNAL LH2

• FERMILAB STANDARDS (FESHM)
• Guidelines for the Design, Review and Approval
  of Liquid Cryogenic Targets
• Liquid Hydrogen System Guidelines
• Storage and Use of Flammable Gases
• Cryogenic System Review
• Oxygen 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

6
FNAL Safety Requirements for Windows

• Absorber Windows
• Design
• Internal WAMP 25 psid
• FEA showing max. allowable stress lt 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 10 psid set point. In
  addition, a PLC-controlled vent valve will be
  installed

7
FNAL Safety Requirements for Windows (2)

• Vacuum Windows
• Assumption Design assumes that the beampipe
  attaches to absorber vacuum windows, therefore
  vacuum exists on both sides of the windows
• Design
• Internal WAMP 25 psid
• External MAWP 15 psid
• FEA showing maximum allowable stress is lt2/3 Sy
  or lt 0.4 Su
• Material certification
• Window drawing
• Tests
• Burst test 5 vacuum windows at room temp. to
  demonstrate a burst pressure of at least 75 psid
  for all samples. (pressure exerted on interior
  side of vacuum volume).
• Non-destructive tests at room temperature
  External pressure to 25 psid to demonstrate no
  failures no creeping, yielding, elastic
  collapse/buckling or rupture

8
FNAL Safety Requirements for Controls

• Safety Interlocks (Quadlog PLC) and Controls
  (Apacs)
• Functions
• Control operations of the LH2 system
• Safety 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 hall
• An estimate of failure severity and frequency
  will be made as well as the consequences to
  personnel and equipment
• The 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

9
MICE Staging and experiment

1. Filling, cooling and purging cycle
2. Data acquisition and controls
3. Absorber variations
4. Safety triggers and recovery..
5. Magnet quench
6. Cryogenic failure
7. Absorber failure
8. Vacuum failure
9. Upgrades (wedges, H2 gas..)
10. System stability checks
11. Maintenance cycle

10
Instrumentation Safety

• Temperature/density uniformity inside LH2
• Safety instrumention inside vacuum area
• Detectors for cooling measurements

Safety Issues 1. Limits the amount of
power/(area or vol) 2. Physical size of the
signal feedthroughs 3. Distance away from target
(e.g. VLPC readouts) 4. Seals from signals to
electronics wires fibers tubes