The event occurred during welding works which ignited accidentally released hydrogen. The plant had been partially shut down for repairing works to a pipe affected by internal cracks. The repairing schedule foresaw grinding and external welding of the defective parts. Despite the purging phase to guarantee drying of the pipe section, further water leakage was hindering the work, so that additional measures was taken, also to avoid too much gas waste. The hydrogen entered the system by a leaking valve, undetected at the time of job preparation and during subsequent checks.

Fire broke out along a transition corridor combining several underground pipelines transporting hazardous substances, including hydrogen, kerosene and ethylene oxide. The fire was brought under control within a few minutes thanks to the limited size of the leak.

A leak occurred on a 4 inch hydrogen main gas line which ran along a pipe bridge at the east end of a first stage compression plant building, ignited.The source of ignition was hot welding sparks arising from work being carried out by contract personnel whilst installing a new chlorine line above the hydrogen main on the pipe-bridge.Before the welding work was carried out, an explosivity test had been carried out in the area and a nil result had been entered on the work permit.An investigation into the incident found that the removed section of the hydrogen main revealed an elliptical hole 2 c

Hydrogen ignition during welding on a VSC-24 spent fuel cask Pursuant to 10 CFR 72.210 - fuel in an independent spent fuel storage installation at its Point Beach Nuclear Power Plant. The inspection of activities conducted under that general license, found that the weight of the multi-assembly sealed basket (MSB) shield lid was not appropriately translated from the safety analysis report into several procedures and there was an inadequate procedure for placing the MSB transfer cask into the spent fuel pool.

A hydrogen leak occurred on the a coolant pipe of an electrical generator located in the turbine building, at 200 m from the reactor. Because of the welding works ongoing at that moment on the pipe, the hydrogen ignited and an explosion and a fire followed the leak, with one fatality and a severe injury. The fire brigade of the plant were able to extinguish the fire. There has bot been any radioactive release, because the accident occurred in the non-nuclear area of the plant. According to the source (ARIA) the investigation attributed to a human error the cause of the incident.