The contractor was replacing a needle valve and a check valve on the nitrogen purge line to the dispenser because of a small leak at the connection between the needle valve and the check valve. On reinstalling the valves, the contractor installed the check valve backwards, causing the pressure disk in the regulator to fail, venting about 1000 psig hydrogen into the air for about 10 seconds. This was found during testing of the contractor's work before the system was returned to normal service.
A person working in a hydrogen lab unknowingly closed the wrong hydrogen valve and proceeded to loosen a fitting in one of the hydrogen gas lines. The pressure in the 1/4"-diameter hydrogen line was approximately 110 psig. Hydrogen escaped from the loosened fitting and the pressure release resulted in the tubing completely detaching and falling to the floor. The person noted seeing a white stream around the hydrogen jet leak. The person noted a color change and noise change as the leak ignited (this happened in a matter seconds and he did not have a chance to react). The person left the lab and pushed the emergency stop button. Someone else pulled the fire alarm. Both of these actions were designed to close the main hydrogen solenoid (shutoff) valve. The local emergency response view more
A partial pressure sensor for an automated gas environment system (AGES) was not functioning correctly for pure hydrogen flow. While personnel were troubleshooting the problem, a burst disk ruptured resulting in a leak of hydrogen gas and actuation of a flammable gas alarm.
System troubleshooting involved the installation of a small hydrogen gas cylinder and temporary manual valve in an engineered ventilated enclosure adjacent to an instrument sample well. A burst disk associated with the temporary manual valve ruptured upon opening of the gas cylinder valve. The vented gas, exhausting through an engineered exhaust system, triggered the flammable gas detector. Personnel promptly evacuated the area in accordance with established procedures. Appropriate personnel responded to the view more
Unit 1 Plant power was stable at 90% following a plant startup. The Auxiliary Operator (AO) performed a pre-job brief with shift management before adding hydrogen to the main generator. While performing the addition, the AO attempted to verify open a half-inch hydrogen addition valve. The AO was unable to move the valve by hand and mistakenly assumed the valve was stuck on its closed seat. The valve is a normally open valve and the procedure step was to verify the valve was, in fact, open. The AO obtained a pipe wrench to assist in freeing the valve off of its "closed" seat. Using the pipe wrench, the valve handwheel was turned in the open direction. The AO attempted to open the valve by hand again. Unable to move the valve by hand, the pipe wrench was used to further open view more
A plume of hydrogen gas escaped from the offloading valve of a liquid hydrogen delivery truck while transporting hydrogen to a commercial facility. The plume ignited, resulting in a flash and concussion loud enough to be heard inside the nearby building and to set off the building’s seismic event detectors. A small amount of hydrogen gas continued to escape from the trailer tank and burn until a company specialist arrived to manually shut off a critical valve almost eight hours later. In the mean time, emergency response crews called to the scene sprayed water across the hydrogen tank as a precautionary cooling measure. The actual cause of this incident appears to have been primarily driver error. A number of steps required as part of the standard safety procedure were either view more
- = No Ignition
- = Explosion
- = Fire
- = No Ignition
- = Explosion
- = Fire