Disclaimer: The Lessons Learned Database includes the incidents that were voluntarily submitted. The database is not a comprehensive source for all incidents that have occurred.
Facilities should review their process systems to determine if they have valves installed that may be subject to this hazard. If so, facilities should conduct a detailed hazard analysis to determine the risk of valve failure. Detailed internal…
Cause and effect can sometimes be predicted by observing abnormal behavior even when the behavior is within specifications. Operators log equipment data and inform shift management when specifications are exceeded or when unusual equipment…
In this case, failure to recognize a run of tubing still maintaining pressure could have been avoided if such information was provided in a safety briefing. Knowledge of any job is the utmost importance in promoting and maintaining a safe working…
This incident highlights the need to ensure that the performance of special procedures does not place facility equipment in a condition that could lead to entry into a LCO.
Installation
The practice of making gas mixtures in the laboratory should be eliminated, and gas mixtures with a known low hydrogen concentration should be purchased for use. The concentration of hydrogen used should be such that it is not possible to form an…
After this accident, a safety inspection team was organized. An investigation of this incident and an inspection of all other experimental equipment was conducted by the team. As a result of this inspection, the heaters are now hard-wired to the…
When performing maintenance evolutions, proper work control processes must be in place to insure that process systems are adequately prepared, remain in a safe energy state during the maintenance evolution, and are properly restored afterwards.…
This occurrence points to the importance of gathering and organizing all applicable administrative controls and other commitments prior to commencing work. It also re-emphasizes the importance of attention to detail, not only by the person…
The primary lesson learned was that the active hydrogen facility and existing operating procedure, at the time of the accident, were sound. While this now has been determined, the previous form(s) of this system, associated documentation, and…
Some hydride materials (e.g., sodium alanates) may be rapidly exothermic, even pyrophoric, if exposed to water or humid air or slowly exothermic, even pyrophoric, if exposed to oxygen. Reactive materials, including fine metal powders, should be…
The manager in charge acknowledged that, while he made relatively recent modifications to the high-pressure gas storage side of the system and had directed a major rebuilding of various units, the moderate-pressure interconnecting system (the…
This incident illustrates how difficult it is to completely purge hydrogen out of a large, complex piece of equipment. Uniform mixing and dilution is unlikely in all the partially enclosed spaces, crevices, etc. If a hazardous operation such as…
This incident illustrates the danger of hydrogen being inadvertently released through blown water seals. Similar incidents have occurred in non-nuclear industrial facilities, but offgas systems present a special hazard because of the…
The mechanisms and rates by which hydrogen gas is generated and subsequently accumulated in the holding tank need to be fully understood by vendors and employees alike. Active venting, warning signs, and local alarms designed to activate when…
The above described events are an indication of a potential licensee/vendor interface problem. Based on the information received, the vendor was not completely informed via the purchase specifications regarding the service condition to which the…
The hydrogen facility does not meet industrial guidelines for facilities of this type, from the standpoint of (1) the separation distance needed between a hydrogen pipe break and the building ventilation intake to prevent buildup of a flammable…
This incident highlights the need to properly design safety interlocks. These safety interlocks need to be carefully incorporated into the initial building/plant designs and should consider all of the unexpected occurrences, such as the…
The investigative report noted that the explosion could have been prevented by (among other things) a continuous gas analyzer test of oxygen and hydrogen product purity. The continuous analyzer should be interlocked to shut the electrolyzer down…
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