The nuclear plant was a boiling-water reactor with an output of 0.54 million kW. The component affected was a steam piping (inside diameter: 15 cm; thickness: 1.1 cm) of a heat exchanger used for removing residual heat from the reactor. The piping was broken during a test of a high pressure core injection system for cooling water provided for an emergency core cooling system. The incident resulted in a leakage of radioactive gases. The part of the piping broken was located on the 2nd floor of the building, but there were no workers there.

A hydrogen explosion caused burns contaminated with radioactive dust to a member of the plant's maintenance crew. Three other workers escaped injury.The accident occurred in the basement of the plants turbine building during work on an out-of-service recombiner (an equipment that combines hydrogen and oxygen to make water. A review team has found that a leak in a valve on the system allowed the hydrogen gas to build up in the pipe where the employee was working with a grinding wheel.

A potentially explosive situation was reported by safety inspectors at a nuclear waste tank. The waste slurry had formed a thick crust which was trapping hydrogen being continuously generated underneath. The tank has uncertain chemistry and contents.According to the New Scientist article (see references) four million litres of waste "have been behaving mysteriously inside the underground storage tank. Every few months the tank burps releasing a burst of hydrogen and nitrous oxide."Calculation estimated a potential for an explosion equivalent to 230 kilos of TNT.

[NOTE: the sources are not completely clear in describing the system involved in this incident ; the following is the most plausible option according to HIAD validator]The explosion happened in two hydrogen tanks ('receivers') whcih were receiving and storing hydrogen produced by a water electrolyzer via two compressors. The hydrogen was then supplyed to a further non-specified generator. The plant had been shut down on August 24 to 26 and resumed the hydrogen production and storage on August 27.

The accident occurred in a disposal storage for contaminated waste, consisting in a 65-metre shaft flooded with seawater. At the origin of the explosion was the reaction with water of at least two kilograms of sodium and potassium. They reacted violently with the water, producing hydrogen. The explosion opened the ceiling of the storage. A plume of white smoke blowing out to sea was reported by witness. Probably also an emission of radioactive particles occurred.

An in-tank explosion occurred in a gaseous waste decay tank while the plant was in cold shutdown. The gaseous hydrogen present in the tank formed a flammable mixture and ignited due to air contamination of the inert nitrogen system used to control the hydrogen-oxygen concentrations in the tank. This resulted in a release of about 8.8 curies of noble gases and minor tank damage.Generally, the gas in pressurized water reactor waste gas systems is hydrogen rich and the oxygen concentration must be controlled to prevent flammable gas mixtures.

A short circuit occurred in a bus bar system in a transformer building, causing a fire in adjacent switches. This was followed by the tripping out of the three refinery turbo-alternators, cutting off the National Grid supply, and loss of refinery electrical power, steam and air supplies for some 30 minutes.The cause of the incident was a fault in a 15 kiva circuit breaker voltage transformer which led to a bus bar fault During the power loss and shutdown of plant, a hydrogen leak developed on a valve, and a tube of a fin-fan condense bank failed.

Piping breakage at atomic power plant- Steam piping (inside diameter: 15 cm; thickness: 1.1 cm) of a heat exchanger for removing residual heat from a reactor was broken during the test of a high pressure core injection system for cooling water provided for an emergency core cooling system at a boiling-water light water reactor with an output of 0.54 million kW, thus resulting in leakage of radioactivity-containing gases. The part of the piping that was located on the 2nd floor of the building as broken but there were no workers there.

A hydrogen-cooled electricity generator exploded inside a coal-fired power plant killing two workers and injuring fifty others. An investigation into the incident found that a hydrogen gas leak may have caused the explosion, which occurred as the generator was being tested following routine maintenance.A press release of the company (see references) immediately after the accident stated that their "safety procedures may not have been followed"

At about 3:15 p.m. on Dec. 3 2003, personnel in the Expended Core Facility at the Naval Reactors Facility heard a loud, unexpected noise. Upon investigation, personnel found an irradiated material storage container fell from its normal submerged storage location in the water pool to the pool floor, and that the lid had come off.The lid was found about 10 feet away from the container on the bottom of the water pool. No nuclear fuel was involved.According to a press release, a team of technical experts determined the most likely cause was a hydrogen gas explosion within the container.