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.
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.…
It is important to understand the requirements and standards associated with safe equipment design (especially electrical equipment containing an internal ignition source with flammable gas) in potentially explosive atmosphere environments.…
1. Management must ensure that operating decisions are not based primarily on cost and production. Performance goals and operating risks must be effectively communicated to all employees. Facility management must set safe, achievable operating…
Incorporate external operating experience lessons learned into site program controls. Other nuclear plants had similar strand failures and back-of-core issues that were not evaluated for impact on procedures or system/component health plans.…
The following corrective actions have been taken:
The non-return valve was dismantled, cleaned, and tested. Following positive testing, the system was restarted and pressurized without any further malfunctioning.
The hydrogen…
Specific response drills/exercises need to be conducted yearly. In this case, all safety systems worked as they should and outside emergency responders were not needed.
Performing other tasks while filling hydrogen tube trailers, such as…
1. Evaluate any change in normal procedures or conditions for storage of aluminum hydride products. In this case, the aluminum hydride material was typically stored at -35°C in the glove box freezer. However, due to a change in glove boxes, this…
1. Ensure that equipment and materials exposed to hydrogen are compatible with a hydrogen environment (even hydrogen-service-rated equipment).
2. Equipment designs in a hydrogen environment that use the fracture toughness for 17-4…
The packing in the flow control valve should be replaced periodically. A planned investigation will determine the optimum time period for packing replacement.
Inadequate Safeguards - The system was designed with low-point drains to facilitate water removal, however, these were found to be inadequate in both location and size. The fact that the mixed feed pre-heat coil was not self-draining was unknown…
The following recommended actions were identified:
Reemphasize the current lab management policies and practices on how process changes are evaluated for direct/indirect impacts on the process.
Reinforce with lab workers the…
1. All samples with potential for hydrogen buildup should be limited to ground shipment only. (This shipment was by ground and air. If this incident were to have happened in an airplane, the consequences may have been worse.)
2. All…
A hydrogen tube pressure indication system needs to be developed that is robust enough to withstand an accident, indicates hydrogen pressure regardless of valve position, and would be visible from a safe distance during an accident situation.…
Increased structural protection is needed at the back of a hydrogen tube trailer to protect the vulnerable hydrogen systems components in this location (valves, pressure-indicating devices, manifolds, piping) in case of an accident. Side…
A hydrogen tube pressure indication system needs to be developed that is robust enough to withstand an accident, indicates hydrogen pressure regardless of valve position, and would be visible from a safe distance during an accident situation.…
Replace the existing copper and carbon steel hydrogen pipeline with ¾-inch schedule 40 stainless steel.
Reroute the new hydrogen line in the preferred location.
Locate new hydrogen shut-off valves in a more convenient location.…
The uncontrolled release of hydrogen occurred as a result of the rupture of the No. 6 hydrogen storage tube’s burst disc. This disc failed in response to being overloaded by mechanical stresses developed as water expanded and formed ice while in…
Recommendation 1 - Overhaul and replace the diaphragms on all cells showing low-purity results. Check on a routine basis the individual cell purity levels to monitor the deterioration of performance of individual cells. Certain contaminants are…
In the future, refining, petrochemical, and chemical industries need to review material verification programs to ensure that the maintenance procedures include sufficient controls and positive material identification (PMI) testing to prevent…
The accident proves that under special circumstances, the potential hazard connected with unforeseen microbial gas formation and accumulation should not be neglected. Thus, to avoid new accidents at the paper mill described above, the tower has…
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