This occurrence underscores the importance of completing a hazard analysis for each different process. Non-safety-related systems or equipment may be used for purposes other than their primary purpose so long as potential hazards are identified…

The following corrective actions have been taken:

• The non-return valve was dismantled, cleaned, and tested. Following positive testing, the system was restarted and pressurized without any further malfunctioning.
• The hydrogen…

1. Specific response drills/exercises need to be conducted yearly. In this case, all safety systems worked as they should and outside emergency responders were not needed.
2. Performing other tasks while filling hydrogen tube trailers,…

1. The trailer involved in the incident used a frangible burst disk based upon the proprietary metal compound designated as Inconel #600. Random sampling of similar pressure relief devices from the same trailer showed that all of them failed at…

The uncontrolled release of hydrogen occurred as a result of the rupture of the No. 6 hydrogen storage tube’s burst disc. This disc failed in response to being overloaded by mechanical stresses developed as water expanded and formed ice while in…

1. Revise fire protection operations surveillance tests to include a maximum of 110% of the agent net weight to prevent over-filled cylinders from being placed in service.
2. Identify cylinders currently in service that exceed the 110…

Refueling operations need to be conducted in a careful and attentive manner, and operators need to be aware of the potential consequences of their actions.

• Verify that all PRDs contain fuse-backed adapters.
• Explore elimination of rupture disk PRDs and substitution of spring-style relief valves.
• Develop new hydrogen unloading procedure using a written checklist. * Add…

Metallurgical examination of the two failed disks by light optical microscopy (LOM), scanning electron microscopy (SEM), and energy-dispersive x-ray spectroscopic analysis (EDS) found them to be fabricated from pure nickel with evidence of…

1. Hydrogen safety training should be provided to local emergency responders.
2. Liquid hydrogen installations should be inspected by facility personnel on a frequent basis, consistent with NFPA 55, to verify proper operation and…

1. Place signs on all liquid hydrogen tanks indicating that no water is to be put on the vent stack.
2. An additional secondary backup vent stack was added to liquid hydrogen tanks. This secondary stack is designed to be used only if…

The ignition of the fireball could have been caused by any of the following mechanisms:

• The inverse Joule-Thompson effect of hydrogen (i.e., heating upon expansion)
• Some of the oil and light ends were above their auto-…

Three root-causes were noted during the investigation: (1) the use of incompatible materials in the manufacturing of the PRD valve, (2) improper assembly resulting in over-torquing of the inner assembly, and (3) over-hardening of the inner…

Personnel were focused on the AGES system test and results, not the compatibility of the test equipment. The manual valve was needed to successfully test the system, however the fact that this particular valve could not accommodate the full…