The investigation determined that hydrogen was formed by the reaction of hot aluminum and water, air was admitted via the inspection door, and the mixture was ignited by the hot clinker or sparks from the chisel. Aluminum should have been…

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-…

1. Include the tanks in a regular inspection program. Evaluate their condition and replace if necessary.
2. Fill the tanks only half full with leach material.
3. Keep the material completely submerged in solution.
4. …

• Active GH2 sensors should be installed and continuously monitored in all enclosed buildings near GH2 sources. All buildings near areas where hydrogen is used should be designed to preclude GH2 entrapment (e.g., sloping roof with…

The incident resulted from an inadequate design for the storage location of the copper gas supply tubing (too close to an electrical outlet). The gas supply tubing was too long for its intended purpose and posed a hazard in its coiled state near…

The direct cause of the over-pressurization of the two drums was the repackaging of the phosphoric acid into metal UN1A1 drums and the resultant hydrogen gas generation within the sealed drums. At the time of this incident (1997), 49 CFR and…

The lessons learned from this incident are:

1. Verify the gas that you are using.
2. Avoid using "quick-disconnect" fittings in this type of situation. If they are absolutely needed, there are sets available that ensure that…

Several best practices resulted from this incident and will be implemented if similar circumstances present themselves in the future.

• Close bay door.
• Keep within proximity of bay.
• Be aware of other bays…

A new best practice resulted resulted from this incident. It states that before any work is started, a third party should verify with a visual inspection that the actual equipment to be used matches the planned equipment list/protocol.

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…

All installed and certified safety and emergency systems functioned as designed.

1. The fuel cell turned off immediately after fire detection.

2. The fire suppression system was immediately initiated thereafter.

3. The physical…

1. Incorporate external operating experience lessons learned into site program controls. Other nuclear plants had similar strand failures and back-of-core issues that were not evaluated for impact on procedures or system/component health…

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…

The SS 24-inch pipe that failed was replaced with 1-1/4 Cr 1/2 Mo alloy pipe that is corrosion-resistant to SCC. A revised HTS bypass piping layout was installed to prevent the hazardous conditions that lead to the failure. A detailed hazard…

1. Redundant safety systems prevented this event from becoming an incident. The 1%-hydrogen-concentration-level-triggered fan was backed up by a 2%-hydrogen-concentration alarm. The alarm is continuously monitored (24/7) by a remote Network…

Several procedural and design changes should be considered for the future:

1. Replace the use of pure hydrogen with a 95:5 mixture of nitrogen and hydrogen to reduce the possibility of an explosive atmosphere occurring. Laboratory…

The turbine components that caused the vibrations were a retrofit design which had been in service for about two years and were under warranty from the vendor. The root cause analysis of the event determined that the damage was caused by a defect…

Recommendations:

1. The using organization should define necessary activities in order to place hydrogen systems in long-term periods of inactivity. The defined activities should address requirements for rendering inert, isolation (i.…

Although the preparation-for-transport procedures were done the same way they were done for previous outreach programs, this time it proved to be a different situation. It is not clear what caused the ignition of the first balloon, which then set…

Safe storage and transportation of balloons filled with a hydrogen-oxygen mixture is a very risky undertaking. There are few scenarios that do not involve enclosed spaces (e.g., a car) and the potential for static discharge. Perhaps a mesh bag…