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.
Be more sensitive to precursor indications of declining system/component health; in this case the main generator. Insensitivity resulted in material condition deficiencies and elevated risks to generation that are undesirable given the economic importance of this high-value asset.
Follow OEM and industry recommendations for component (stator) preparation for testing and lay-up.
Have a detailed component (generator) Life-Cycle Management Plan.

Additional details regarding probable causes and lessons learned can be found in Attachment 2.

Supporting Documents

Attachment 1 - Photos.pdf

Attachment 2 - Lessons Learned Details.pdf

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

Hydrogen Leak into Main Generator Stator Cooling Water System Causes Nuclear Plant to Shutdown

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