2007 CMBG Conference Bill Kline FirstEnergy Nuclear Operating Company (FENOC) June 19, 2006 Charleston, SC Latent Issues and Lessons Learned Discussion

2007 CMBG Conference Introduction Process and Methodology –Methods for finding latent issues –Techniques for communicating identified issues –Driving the issues to closure –CM process improvement from lessons learned Relationship with inspection programs –CDBI (Component Design Basis Inspection) –50.59 Safety Assessments –Plant Modification Inspections Preparation for Workshop Discussion –Identify issues at your facility –Identify specific mismatch with 3-Ball model –Identify process breakdowns that led issue to be latent –Identify facility remedial actions

2007 CMBG Conference Latent Issue Concept Latent Issues –What are they? –How are they created? –How are they identified? –How do they relate to the 3-Ball model? CDBI Inspection Bases and Objective –Goal is to verify inter-related aspects Initiating Events Mitigating System Functions Barrier Integrity Cornerstones –Accomplished through Inspection Team focus Components vs. Systems Risk significance Plus Low Margin Engineering Operations/ Interface Incorporation of Operating Experience

2007 CMBG Conference Latent Issues – What are they? “Latent” definition –Present or potential, but not yet manifest –To lie hidden, be concealed –What is latent is not clearly visible In terms of 3-Ball model –Unidentified upsets or gaps in CM Equilibrium Design Basis Facility Configuration Information (FCI) Physical Configuration IT’S NOT THE BRICKS, IT’S THE MORTAR –Bricks are the SSCs –Mortar consists of supporting design basis material Design basis calculations Operating and surveillance procedures Modification packages

2007 CMBG Conference Latent Issues – How are they created? Inadequate original review Undocumented plant changes Unanticipated effects of installed modifications Failure to carry over design requirements into operating or surveillance procedures Errors in analysis, design inputs, duplicate or conflicting licensing documents Operating procedure instruction invalidates design calculation (response time) Maintenance errors that affect plant configuration Equipment out of tolerance Not properly tested after modification or maintenance Unexpected degradation in performance of SSCs

2007 CMBG Conference Latent Issues – How are they Identified? Self-revealing through emergent plant issue –Least desirable –Most challenging to plant resources Identified through Scheduled Inspections –Internal and external –May broaden the scope to ascertain extent of condition Uncovered during Modification Design Process –Inconsistencies identified during design basis research –Walkdowns identify conflicting conditions –Modification reviews identify cross-discipline conflict –Review of operator assigned actions determines incompatibilities with old and new assumptions

2007 CMBG Conference Latent Issues – Ties to 3-Ball model Brick and Mortar Analogy –Records or information within each ball constitutes the “bricks” Design – What needs to be there FCI – What we say is there Physical Configuration – What is really there –Links or paths between the balls are the “mortar” Calculation (design) value for setpoint is properly documented in FCI (setpoint procedure) with component in field (physical configuration) operating within design criteria Design assumption for operator action time is documented in event response procedure (FCI) and has been validated as achievable in the field through simulation (physical config.) –Latent Issue reviews are looking for “gaps in mortar” Design assumption not carried through to identify limits in FCI Physical configuration limits not reflected in design assumptions

2007 CMBG Conference 1st Example 1st Example Allowed Changes In Diesel Generator Frequency

2007 CMBG Conference Design Requirements Technical requirements, derived from the design process, that are reflected in the final design. What Needs to be there In this case, most plants let the frequency vary by +/- 2% Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference Diesel Frequency Variations causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the Pump NPSH and flow is impacted by the variation in frequency (speed), such that what we need may no longer meet the published performance criteria Diesel frequency and effect on Pump NPSH and flow Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference The change in NPSH/Speed causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the Pump NPSH and flow impacts the MOVs and AOVs, such that what we need may no longer meet the published performance criteria Pump NPSH and Flow effect on Valve DP’s Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference The change in Pump Speed causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the Pump Speed adds electrical load to the diesel such that what we need may no longer meet the performance criteria Pump Speed changes cause higher loads on diesel electrical supply requirements Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference The change in Diesel Loading causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the electrical load adds consumption of diesel fuel such that what we need may no longer meet the performance criteria Higher diesel loading causes more diesel fuel consumption Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference The change in Pump Motor Load causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the Higher Motor Load adds heat and HVAC Load to the room such that what we need may no longer meet the performance criteria Higher Motor Loads add heat to the local equipment area Example – Diesel Generator Frequency Diesel Frequency Variations

2007 CMBG Conference 2nd Example Valve Response Time Not Included For Vortexing

2007 CMBG Conference Design Requirements Technical requirements, derived from the design process, that are reflected in the final design. What Needs to be there In this case, most plants transfer cooling water supply from a tank to Containment Sumps/Pools Example – Tank Vortexing Prevention of Vortexing

2007 CMBG Conference Valve closure times causes Upset Between Physical Configuration and Design Requirements causing a failure of the SSC to meet performance criteria as designed In this case, the Pump NPSH is impacted by the time for change in valve position, such that what we need may no longer meet the performance criteria Vortexing Requirements and Valve timing Example – Tank Vortexing Prevention of Vortexing

2007 CMBG Conference Lessons Learned – Questions to Ask Design and System Engineering –Are calculation assumptions consistent with acceptance criteria in surveillance procedures? –Do alarm setpoints afford sufficient time for automatic or manual actions to prevent loss of safety function? –Are the credited response times for operator actions consistent with inputs and assumptions in design calculations? –Have modifications been correctly reflected in design basis calculations and design outputs (drawings, specifications, databases, etc.)? –Look for things that you haven’t seen before. Use new eyes, i.e., have System Engineers walk each others’ systems down. –Establish and conduct periodic cross-discipline reviews to probe at an issue from many angles.

2007 CMBG Conference Lessons Learned – Questions to Ask Maintenance –Make sure previously identified deficiencies have not deteriorated beyond condition originally captured. –Was post maintenance testing adequate to demonstrate design basis was restored? –Has there been an undetected adverse trend in the condition of the component, its environment, or support equipment? –Are maintenance procedures in agreement with design requirements such as allowable materials and tolerances?

2007 CMBG Conference Lessons Learned – Questions to Ask Operations –Have time sensitive activities been validated, and has the validation been documented? –How long ago was the activity validated? If it was several years ago, plant conditions may have changed that affect the validation. –Are staged repair parts or tools credited? If so, are they available and accessible? –Are there always sufficient people available to perform the task? –Are there always capable people available to perform the task?

2007 CMBG Conference CDBI Use of Operating Experience Have we learned from our collective experience? –Effective review for generic or common issues? –Properly represent Initiating Events, Barrier Integrity Cornerstones? –Objective evidence that OE issue has been resolved? –Has all the FCI been properly updated? –Does OE review adequately address potential margin issues? Analytical (design) Margin Operations Margin Maintenance Margin Complexity Margin

2007 CMBG Conference Examples: Operating Experience Plant failure to establish proper fouling factors inside the tubes for the containment fan coil cooling units Failure to ensure necessary torque values terminal connectors were specified in the maintenance procedure for safety related and important to safety 250Vdc, 125 Vdc, and 48Vdc batteries Failure to complete a evaluation for an operating procedure change that substituted remote manual operator actions for automatic actions during a station blackout. Failure to assess Molded Case Circuit breaker failures within the corrective action program.

2007 CMBG Conference Operating Experience Numerous errors and omissions in several pipe support calculations: –Unsubstantiated Reductions In Moment Forces, –Un-conservative Omission Of Horizontal Seismic Forces And Anchor Bolt Shear Loads, –Failure To Analyze Local Web And Flange Stresses, –Un-conservative Weld Size Assumptions, –Analyzing Upset Loading Conditions And Ignoring Faulted Loading Conditions.

2007 CMBG Conference Summary CDBI is structured to uncover latent issues –Focus on the links between the design and how it is communicated to other plant groups –Be creative in identifying challenges to margin –Understand the limitations of your high risk/low margin components –Be able to identify potential process weaknesses Probe that weakness to identify extent of condition –Need to investigate increasing levels of detail to “pull the string” Diesel Generator Frequency Variation Example –Relate identified discrepancies to gaps in the 3-Ball model with the intent to close the gap

2007 CMBG Conference Closing Remarks Learn from other station’s findings –Identify NRC findings in the INPO OE system –Ask the question “How is my station the same as the station with the finding?” Always start with questioning base assumptions –Identify basis for why current situation is acceptable Understand your Design and Licensing Bases Identify and understand the impacts –Risk to the station (immediate and long-term) –What it will take to correct the situation Both the physical changes and the process improvements

2007 CMBG Conference QUESTIONS? Workshop at 1:00 PM Stono Ballroom