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The 2nd NPDGamma Experiment Safety Review - Liquid Hydrogen Target. Seppo Penttila NPDGamma project manager June 09, 2008 SNS. We try to cover. Findings from the 1st LH2 Target Review Introduction to the LH2 target systems - technical introduction
NPDGamma project manager
June 09, 2008
A Committee composed of
Robert Dean, Ian Evans, Phil Ferguson, Max Gildner, Ken Herwig, Hal Lee,
George Rennich, Patrick Thorton, Steve Withrow, and Allen Crabtree.
It met in Room C-156 of the CLO on September 25, 2007 at your request to
review the Preliminary Design of the NPDGamma Hydrogen Target.
The Committee heard presentations from you and Seppo Penttila on the
overall design of this instrument and in particular details regarding the liquid
• The overall design is quite mature due to the fact that this instrument was actually
previously operated at LANL.
• The test enclosure that houses the hydrogen target has not yet been classified.
• The decision to fabricate an ASME code-stamped cryostat ensures a robust design.
• Some mechanical fittings and couplings could be eliminated or located in ventilated
• Hydrogen cylinder storage cabinet location has not been finalized.
• Hydrogen vent lines are currently routed through normally occupied areas between the
sample cave and the roof (in particular, next to the mezzanine walkway).
• Currently the projected dose rate at the sample cave roof exceeds the 0.25 mrem/h
• In some areas, Beamline 13B relies on beamline 14 shielding in order to meet design
objectives for radiation exposure during operations.
• The 13A beamline pipe stub extends into the 13B sample cave.
• ODH issues have not been adequately addressed.
a 16 liter liquid hydrogen target is required.
Most of proposed technical and safety concepts were tested at LANSCE. Improvements and modifications are proposed to the LANSCE baseline target. These are changes required by physics performance, facility, or mandated by Code.
Liquid Hydrogen Target System and Safety, June 5, 2008.
Document, June 5, 2008.
Pressure in H2 cylinder
up to 1800 psi
The LH2 Target - Cryostat and LH2 Vessel
The most probable event scenario is a loss of the isolation vacuum:
In Interlock System: isolation vacuum pressure gauge and RGA would close H2 source, isolation vacuum valves, and local (at LANL) H2 Alarm buzzer+red flashing light will turn on.
Lines have many of CF and VCR joints inside
Enclosure ventilated by chimney-effect and H2 buoyancy.
No ignition sources in enclosure.
Vent stack filled with Ar (NEW)
The relief system;
piping, relief valves, check valves, and rupture disks form the H2 boundary and thus isolate the H2 from air and allow safe relief of hydrogen gas outside the Target Building during normal and emergency venting.