CHECK OUT OUR MOST RELEVANT INCIDENT LISTINGS! 

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.

Carbon steel Nelson curve methodology cannot be depended on to prevent HTHA equipment failures and cannot be reliably used to predict the occurrence of HTHA equipment damage. Revisions to recommended practices should be considered regarding the…

Because the bottle was located outside at the time of the event, and the hydrogen did not find a source of ignition while venting through the relief valve, nothing serious happened. The failed regulator was replaced and operations continued.…

The following actions were proposed as a result of this incident: The company in charge of valve calibration and maintenance will be subject to approval of the plant service inspection team. Plant operating procedures will be improved. The…

In addition to the probable causes listed above, the lack of a standard operating procedure for hydrogen leak detection was one of the probable causes of this incident. Additional contributing factors included the following:
- Severe pipe…

Based on the results of the company investigation and analysis of an amateur video, the company determined that the incident could have been caused by the failure of one of the following plant components:
· pipes leading to the reactor…

The SS 24-inch pipe that failed was replaced with 1-1/4 Cr 1/2 Mo alloy pipe that is corrosion-resistant to SCC. A revised HTS bypass piping layout was installed to prevent the hazardous conditions that lead to the failure. A detailed hazard…

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…

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.…

For the use of mechanical fittings in hydrogen service, administrative controls should be in place, as in this case, to ensure that leak testing is conducted on a regular basis. It should never be assumed that every fitting is tight. Additional…

Operation and management of the hydrodesulfurization unit should be strengthened to account for abnormal phenomena such as local corrosion.
The safety review system for remodeling existing equipment and facilities should be strengthened.…

The plant tried to increase production and decrease workload, but failed to notice the potential negative outcomes of this change.
It is necessary to thoroughly simulate all potential negative outcomes of a change in procedures.

The dilution water for making a polythionic acid aqueous solution was changed from industrial water to pure water to lower the chlorine concentration in the piping.
Water that accumulated in the drain was removed before heating began.…

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…

These events show the importance of preventing combustible gas mixtures from accumulating in piping. In both of the above described events, hydrogen and oxygen gases apparently accumulated to a combustible level which then catastrophically failed…

The lessons of this event fall into five categories: (1) proper in-plant communications during events, (2) proper valve application for use with hydrogen, (3) excess flow check valve set point, (4) heating and ventilation and air conditioning (…

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…

An important lesson to be derived from this incident is the need to carefully engineer and test all repairs and modifications to high-pressure process equipment.

Installation

Fittings need to be visually inspected to insure ferules are in place and correctly positioned prior to swageing.
Research staff are responsible for communicating system specifications [gas type, Maximum Allowable…

Hydrogen distribution lines should be designed and carefully inspected to ensure process equipment in the area is correctly and safely installed. Equipment subject to vibration should not be placed in contact with hydrogen lines or with other…

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…

Key:

  • = No Ignition
  • = Explosion
  • = Fire
Hydrogen Incident Summaries by Equipment and Primary Cause/Issue
Equipment / Cause Equipment Design or Selection Component Failure Operational Error Installation or Maintenance Inadequate Gas or Flame Detection Emergency Shutdown Response Other or Unknown
Hydrogen Gas Metal Cylinder or Regulator   3/31/2012
4/30/1995
2/6/2013
4/26/2010 12/31/1969     3/17/1999
11/1/2001
12/23/2003
Piping/Valves 4/4/2002
2/2/2008
5/11/1999
4/20/1987
11/4/1997
12/31/1969
8/19/1986
7/27/1991
12/19/2004
2/6/2008
10/3/2008
4/5/2006
5/1/2007
9/19/2007
10/31/1980
2/7/2009 1/24/1999
2/24/2006
6/8/1998
12/31/1969
2/7/2009

9/1/1992
10/31/1980

10/3/2008  
Tubing/Fittings/Hose   9/23/1999
8/2/2004
8/6/2008
9/19/2007
1/1/1982 9/30/2004
10/7/2005
  10/7/2005  
Compressor   10/5/2009
6/10/2007
8/21/2008
1/15/2019
    10/5/2009 8/21/2008  
Liquid Hydrogen Tank or Delivery Truck 4/27/1989 12/19/2004
1/19/2009
8/6/2004 12/31/1969   1/1/1974 12/17/2004
Pressure Relief Device 7/25/2013
5/4/2012
1/15/2002
1/08/2007
12/31/1969        
Instrument 1/15/2019 3/17/1999
12/31/1969
2/6/2013
    11/13/73    
Hydrogen Generation Equipment 7/27/1999     10/23/2001      
Vehicle or Lift Truck   7/21/2011         2/8/2011
12/9/2010
Fuel Dispenser   8/2/2004
5/1/2007
6/11/2007
9/19/2007
  2/24/2006
1/22/2009
     
Fuel Cell Stack            

5/3/2004
12/9/2010
2/8/2011

Hydrogen Cooled Generator       12/31/1969
2/7/2009
     
Other (floor drain, lab
anaerobic chamber,
heated glassware,
test chamber,
gaseous hydrogen
composite cylinder,
delivery truck)
  11/14/1994
7/21/2011
7/27/1999
6/28/2010
8/21/2008
12/31/1969
3/22/2018
    6/10/2019
  • = No Ignition
  • = Explosion
  • = Fire