Transcript Hydrogen and Cryo

MICE Hydrogen System Design
Tom Bradshaw
Iouri Ivaniouchenkov
Elwyn Baynham
Columbia Meeting June 2003
MICE Cryogenic Components:
• Decay Magnet – part of beam line – early
installation and commissioning. Will have
its own refrigerator
• Implies 9 cryogenic modules:
–
–
–
–
3 x Hydrogen absorber and Focusing coil pair
2 x Spectrometer coils
2 x Coupling coils
Scintillating fibre detector cryostat
MICE Stages
•
•
•
•
•
Step 1 Decay magnet + Sci-Fi
Step 2 plus spectrometer
Spring
2006
Step 3 plus spectrometer
Step 4 plus absorber/focus + hydrogen
Step 5 plus coupling absorber/focus +
2007
hydrogen
• Step 6 plus coupling absorber/focus +
hydrogen
This implies a modular design for the absorber hydrogen
system
Basic Layout
Gas Store
Spectrometer
SciFi Detector
Absorber/Focus
Compressors
14K
4K
Return
Coupling
4K
Absorber/Focus
Cold box
14K
Coupling
Absorber/Focus
Etc….
Decay Magnet
Gate valve
Powered valve
Relief Valve
Refrigerator
Spectrometer
Hydrogen Design - Principles
What we are trying to do in the design is:
•Make it truly failsafe and passive – no active intervention is
required to get the hydrogen out of the system in the event of a
problem.
•Minimise the amount of hydrogen.
•Minimise the volume that has to be considered to be a hydrogen
area.
•Make it modular to allow for staging.
•Minimise interactions between the absorbers to keep the system
simple and reduce consequential faults.
•Prove we can do it for a neutrino factory
Hydrogen Design - Description
Baseline
Have gas tanks outside the experimental area piped in – Iouri will
show layouts in talk tomorrow.
Design is passive.
Any emergency relief venting is through evacuated buffer volume
– volume of this TBD but may just be a large diameter pipe.
Helium purge may be preferable to nitrogen because of sludge and
heat capacity issues.
Have an igloo around each of the hydrogen modules vented
through the roof – layouts TBD because it is complicated by
several issues.
Hydrogen flow and safety system
Version: 09/06/2003
VP
P
P
He / N2 Purge
system
Vent outside
flame arrester
Hydrogen tank
Volume: 11 m3
Pressure > 0.1 bar
14 K He
from Cold box
18 K He
to Compressor
via Radiation shield
X2
Fill valve
P
P
X2
H2 Gas bottle
1.7 bar
P
2.1 bar
12 litre Buffer tank
Liquid level gauge
Vent valve
P
H2 Detector
Vacuum
Ventilation
system
H2 Detector
Internal Window
Vent outside
flame arrester
LH2 Absorber
H2 Detector
70 K Safety window
P
Vent valve
LHe Heat
exchanger
Vent outside
flame arrester
Evacuated vent
buffer tank
Vacuum vessel
Volume:
VP
VP
Hydrogen module enclosure (igloo)
P
Pressure
gauge
P
Pressure
regulator
Valve
Pressure
relief valve
Non-return
valve
Bursting disk
VP
Vacuum pump
Hydrogen Storage – an Option
Hydrogen storage at STP will require three x 11m3
Vessels
Possibly manageable for MICE but not for a neutrino
factory!
Alternative storage solutions being investigated – use
of metal hydrides.
Hydrogen storage
Energy research unit at
RAL is conducting a
small feasibility study
Commercially available –
designs for automotive and fuel
cell use
Absorbtion (exothermic) and
release (endothermic) controlled
by varying temperature
Large “compression” factor
e.g. Ergenics ST-90 (pictured)
61x30x7.6 cm stores 2550 litres in
a volume of 13.9 litres factor of
183
Ergenics Unit
JSW Unit
Cooling power Requirements
Baseline requirement is for :
Absorbers
50W per module at 14K
(He flow 2.4 g/s ΔT=4K)
Focus Coils
(MAC Estimate – any advance ?)
4K
14K Leads
5.2W 22W
0.18 g/s
From M Greens paper but need new estimates based on current
designs – Any thermal models ?
In process of clarifying refrigeration requirements so input is needed !
END