A significant hydrogen leak occurred during refueling of the onboard hydrogen storage tank of a fuel cell-powered lift truck while it was completely depowered. The in-tank shutoff solenoid valve had recently been replaced, and this was the initial refueling event after the replacement. The fuel zone access panel was removed to allow constant visual leak checking with Snoop leak-detection fluid. The event occurred during the final pressure testing of the repaired system when an O-ring failed at approximately 4500 psi, releasing the entire contents of the hydrogen tank in about 10 minutes. The dispenser hose/nozzle was immediately disconnected, and the leak location was quickly isolated to the tank/valve interface. A 30-foot boundary around the lift truck was cleared of personnel and view more
Within the International Space Station (ISS) oxygen generator, an increase in differential pressure across a pump supplying return water to a PEM electrolyzer fuel cell stack had persisted over a 4-month period and was approaching the shut-off limit for the system. This decrease in performance was suspected to be caused by water-borne catalyst fines containing platinum black and Teflon®* binder materials, shed by the fuel cell stack, and accumulated within the pump's inlet filter. Maintenance in the field was required.
The system had been designed for factory maintenance, and no contingency had been planned to handle field maintenance for such a circumstance. An initial assessment of hazards for the proposed filter maintenance raised the concern that opening the water line view more