IR 05000348/2011012
ML111960460 | |
Person / Time | |
---|---|
Site: | Farley ![]() |
Issue date: | 07/15/2011 |
From: | Scott Shaeffer NRC/RGN-II/DRP/RPB2 |
To: | Stinson L Southern Nuclear Operating Co |
References | |
IR-11-012 | |
Download: ML111960460 (46) | |
Text
uly 15, 2011
SUBJECT:
PUBLIC MEETING SUMMARY - JOSEPH M. FARLEY NUCLEAR PLANT - DOCKET NOS. 50-348 AND 50-364
Dear Mr. Stinson:
This refers to the Regulatory Conference conducted on July 12, 2011, in Atlanta, GA. The purpose of the Regulatory Conference was to provide opportunities to discuss the safety significance of the preliminary White finding associated with one Apparent Violation that was documented in NRC Inspection Report 05000348/2011012 and 364/2011012 (ML111590912).
The findings dealt with the failure to maintain the configuration of the 1A reactor coolant pump (RCP) oil lift pump system in accordance with plant design and drawings. This resulted in an electrical short on November 10, 2010 that caused a fire on the Unit 1 main control room (MCR)
1A RCP board handswitch. This conference also addressed whether enforcement action is warranted for the associated Apparent Violation.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter will be available electronically for public inspection in the NRC Public Document Room (PDR) or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS).
ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Should you have any questions concerning this meeting, please contact me at (404) 997-4521.
Sincerely,
/RA/
Scott M. Shaeffer, Chief Reactor Projects Branch 2 Division of Reactor Projects
Docket Nos.: 50-348, 50-364 License Nos.: NPF-2, NPF-8
Enclosures:
1. List of Attendees 2. NRC Agenda 3. SNC Powerpoint Presentation
REGION II 245 PEACHTREE CENTER AVENUE NE, SUITE 1200 ATLANTA, GEORGIA 30303-1257 Enclosure 1 FARLEY REGULATORY CONFERENCE Atlanta, GA July 12, 2011 Name (Print)
_____________J. Munday_____________
_____________R. Nease ______________
_____________G. McCoy______________
_____________L. Suggs ______________
_____________R. Fanner______________
_____________G. Wiseman____________
_____________D. Chung______________
_____________E. Crowe______________
_____________W. Rogers_____________
_____________W. Jones______________
_____________R. Croteau_____________
_____________L. Wert________________
_____________S. Sparks______________
_____________S. Shaeffer____________
_____________S. Rose_______________
_____________T. Lighty______________
Title and Organization Division Director NRC RII/DRS
_Branch Chief NRC RII/DRS/EB2_______
_Branch Chief NRC RII/DRP/RPB5______
_Inspector NRC RII/DRS/EB2__________
_Inspector NRC RII/DRS/EB2__________
_Senior Inspector NRC RII/DRS/EB2____
NRC NRR/DRA/PRA Operational Support
_Senior Resident Farley NRC RII/DRP___
_SRA NRC RII/DRP/RPB7_____________
_Deputy Division Director NRC RII/DRP_
_Division Director NRC RII/DRP _______
Deputy Regional Administrator NRC RII_
Senior Enforcement Specialist NRC RII__
_Branch Chief NRC RII/DRP/RPB2______
Sr. Project Engineer NRC RII/DRP/RPB2
_Project Engineer NRC RII/DRP/RPB2__
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 245 PEACHTREE CENTER AVENUE NE, SUITE 1200 ATLANTA, GEORGIA 30303-1257 Enclosure 1 FARLEY REGULATORY CONFERENCE Atlanta, GA July 12, 2011 (Via Teleconference)
Name (Print)
_____________M. Ashley___________________
_____________S. Meng Wong_______________
_____________A. Klein_____________________
_____________S. Lee______________________
_____________J. Hyslop___________________
_____________N. Coleman_________________
_____________J. Circle____________________
_____________R. Gallucci__________________
_____________B. Martin___________________
_____________D. Harrison_________________
________________________________________
________________________________________
________________________________________
________________________________________
________________________________________
________________________________________
Title and Organization NRC HQ/NRR
_NRC HQ/DRA____________________________
_NRC HQ/DRA/AFPB______________________
_NRC HQ/DRA____________________________
_NRC HQ/DRA/FRB_______________________
_NRC HQ/OE_____________________________
_NRC HQ/NRR/DRA/APOB_________________
_NRC HQ/NRR/DRA/APLA__________________
_NRC HQ/NRR/DORL______________________
_NRC HQ/DRA____________________________
_________________________________________
_________________________________________
_________________________________________
_________________________________________
_________________________________________
_________________________________________
Enclosure 1
Enclosure 2 2 Enclosure 2 REGULATORY CONFERENCE AGENDASOUTHERN NUCLEAR OPERATING COMPANYJULY 12, 2011NRC REGION II, ATLANTA, GEORGIAI.OPENING REMARKS AND INTRODUCTION II. NRC REGULATORY AND ENFORCEMENT POLICY III. STATEMENT OF ISSUE AND APPARENT VIOLATION IV. SOUTHERN NUCLEAR OPERATING COMPANY V. TRANSITION TO CLOSED SESSION (If Required)a. PUBLIC QUESTIONSb. NRC REMARKS/BREAKc. SOUTHERN NUCLEAR OPERATING COMPANYVI. BREAK/NRC CAUCUS VII. NRC FOLLOW UP QUESTIONS VIII. CLOSING REMARKS IX. PUBLIC QUESTIONS (If Not Previously Performed)
Enclosure 3 Farley Nuclear Plant NRC Regulatory Conference July 12, 2011Mark J Ajluni, PE Nuclear Licensing DirectorJohn D Lattner, PEPrincipal Engineer -Fire ProtectionKen McElroy RIE Program Manager 2 Enclosure 3 Agenda*Introductions
- Objectives
- Presentation
- Wrap-Up and Conclusion 3 Enclosure 3 Objectives 1.To provide new information about the event2.To prove the handswitch fire that occurred on Nov. 10, 2010, in the Unit 1 control room was a non-challengingfire per the guidance of NUREG/CR 68503.To demonstrate that the event is not risk significantand should be characterized as green 4 Enclosure 3 The Event*Calibration of 1A RCP oil lift system
- Broken conduit found
- Operators later attempted start of the 1A RCP and detected burning inside the handswitch
- Operator responded by opening panel and blowing on the switch box enclosure
- At the same time the circuit opened and the burning stopped 5 Enclosure 3
6 Enclosure 3 Handswitch InternalsSpade TerminalsSpade Terminal RegionContacts Normally Open 7 Enclosure 3 Handswitch in Closed PositionContacts Closed 8 Enclosure 3 Handswitch Spring Returns to OpenArcing 9 Enclosure 3 Handswitch Damage 10 Enclosure 3 Testing ResultsBecause we are dealing with a specific wiring arrangement and switch all seven SNC tests of handswitch fault indicate the same location for damage and the repeatable nature of failure for this particular fault.
11 Enclosure 3 Handswitch Construction
- Fire resistive construction of switch block
- Does not melt or drip plastic
- Fire resistive construction of switch housing
- Objective of testing was to confirm how the switch responds to shorted conditions 12 Enclosure 3 Main Control Board Handswitch 13 Enclosure 3 Main Control Board Handswitch 14 Enclosure 3 Main Control Board Handswitch 15 Enclosure 3 Operator Intervention
- The operator action had no impact on putting out the fire *Switch is well placed in fire retardant enclosure making direct air flow to the point of combustion impossible*The Condition Report assumes what the operator initially believed at the time, that he blew out the fire*Switch will self-extinguish when current path becomes interrupted *Operator action was inconsequential, testing shows the fire will self-extinguish anyway 16 Enclosure 3 Main Control Board 17 Enclosure 3 No Potential for Fire Spread
- Handswitchfire self-extinguishes
- Confirmed by testing
- Handswitchfire not of sufficient duration or intensity to ignite secondary combustibles
- Test thermocouples
- CHRISTIFIRE test results
- Fire resistive properties of cables and handswitchmaterials*No hot gas layer formed within panel
- Conclusion: No potential for fire spread 18 Enclosure 3 NUREG/CR-6850 Appendix C Objective Classification CriteriaNUREG/CR-6850 Objective CriteriaFNP EventA hose stream, multiple portable fire extinguishers, and/or a fixed fire suppression system (either manually or automatically actuated) were used to suppress the fireNo automatic or manual suppression usedOne or more components outside the boundaries of the fire ignition source were affectedNo evidence of anycollateral damage outside of the fire ignition sourceCombustible materials outside the boundaries of thefire ignition source were ignitedNo ignition of secondary combustiblesIf any one of the following exist, the event is challenging 19 Enclosure 3 NUREG/CR-6850 Appendix C Objective Classification CriteriaNUREG/CR-6850 Objective CriteriaFNP EventActuation of an automatic detection system Event did notproduce sufficient smoke to actuate the main control room detection system. An ionization smoke detector is located on the ceiling directly behind Section C of the MCBA plant trip was experiencedEventdid not cause a plant trip. The unit was in cold shutdown.A reported loss of greater than $5,000Physical damage limited to the handswitch (< $1,000)A burning duration or suppression time of10 minutes or longerBurning duration was less than two minutesIf any two of the following exist, the event is challenging 20 Enclosure 3 NUREG/CR-6850 Appendix C Subjective Classification CriteriaNUREG/CR-6850 Subjective CriteriaFNP EventIt is apparent that active interventionwas needed to prevent potential spreadOperator blowingon the switch enclosure was insignificant intervention. Test data demonstrates the handswitchfire self-extinguishesThere are indications that heat was generated of sufficient intensity and duration to affect components outside the fire ignition sourceNo evidence of heat damageto any components outside of the fire ignition sourceThere are indications that flames or heat was generated of sufficientintensity and duration to cause the ignition of secondary combustibles outside the fire ignition sourceNo ignition of secondary combustiblesSubstantial smoke was generatedInsignificant amount of smoke If any of the following exist, the event is Challenging 21 Enclosure 3 NUREG/CR-6850 Appendix C Subjective Classification CriteriaNUREG/CR-6850 Subjective CriteriaFNP EventIt is apparent that active interventionwas needed to prevent potential spreadOperator blowingon the switch enclosure was insignificant intervention. Test data demonstrates the handswitchfire self-extinguishesThere are indications that heat was generated of sufficient intensity and duration to affect components outside the fire ignition sourceNo evidence of heat damageto any components outside of the fire ignition sourceThere are indications that flames or heat was generated of sufficientintensity and duration to cause the ignition of secondary combustibles outside the fire ignition sourceNo ignition of secondary combustiblesSubstantial smoke was generatedInsignificant amount of smoke If any of the following exist, the event is Challenging 22 Enclosure 3 NUREG/CR-6850 Appendix C Objective Classification CriteriaNUREG/CR-6850 Objective CriteriaFNP EventActuation of an automatic detection system Event did notproduce sufficient smoke to actuate the main control room detection system. An ionization smoke detector is located on the ceiling directly behind Section C of the MCBA plant trip was experiencedEventdid not cause a plant trip. The unit was in cold shutdown.A reported loss of greater than $5,000Physical damage limited to the handswitch (< $1,000)A burning duration or suppression time of10 minutes or longerBurning duration was less than two minutesIf any two of the following exist, the event is challenging 23 Enclosure 3 Non-Challenging Control Room Fires From Fire Events Database Involving InterventionFire IncidentNoDescriptionType of Intervention374SDV high level RPS relay burnedControl room personnel extinguishedthe burning relay425A relay burned due to its "old age"Portable CO 2extinguisherused815A relay burned up in the primary containment isolation panelPortable CO 2extinguisher used2224Defective insulation on windingsled to fault within current protection relayPortablefire extinguisher used2266Small fire found in control panel transformerOperator blew out flame 24 Enclosure 3 Conclusion: Non-Challenging
- None of the objective or subjective criteria was met*Event is non-challenging 25 Enclosure 3 SNC Risk Significance Determination 26 Enclosure 3 Fire Ignition ProbabilityWill Fire Propagate?Fire Severity FactorNon-Suppression ProbabilityShutdown outside MCRRisk Not Significant NoControl Room AbandonmentSDP FactorsHRA Dominated(Unit 2)Suppression before propagation to cable bundle Unit 1 MCR PanelUnit 2 27 Enclosure 3 Phase III SummaryFire IgnitionProbabilityPropagation ProbabilitySuppress before propagationto cable bundleMCR Abandonment ProbabilityShutdown outside MCRCCDPNRC1.00.51.0**1.1E-3 (upper)5.6E-4 (lower)9.9E-35.5E-6 (white)2.8E-6 (white)SNC1.00.5*1.0** (upper)0.01 (realistic)6.3E-56.4E-43.1E-31.0E-7 (green)1.0E-8 (green)** SNC Position -fire not challenging***Considered in MCR abandonment probability 28 Enclosure 3 MCR Abandonment -HVAC
- HVAC Operation-HVAC allows Main Control Room (MCR) to remain manned for larger fires-Larger fires are less likely to occur-Risk of Abandonment reduced by a factor of 20
- Both NRC and SNC used NUREG/CR-6850 methods 29 Enclosure 3 MCR Abandonment (cont.)
- NRC assumed HVAC inoperable
- SNC determined HVAC was operating normally and would continue to operate
- HVAC controls/circuitry physically separated from fire location
- Operators and Fire Brigade would not trip HVAC 30 Enclosure 3 Farley Common MCRFire LocationHVAC Controls 31 Enclosure 3 Shutdown from Outside MCRNRC ValueSNC ValueComments9.9E-33.1E-3
- Dominatedby loss of aux feedwater due to human error
- Equipment failure of AFW negligible
- Difference is due to modeling of human error 32 Enclosure 3 SDP Summary
- Even assuming a "challenging" fire and an event probability of 1.0, the CCDP is green-HVAC was a operating normally making the likelihood of control room evacuation less-SNC performed a more realistic HRA reducing the calculated risk 33 Enclosure 3 Corrective Actions 34 Enclosure 3 Root Cause of the Event
- No written work package generated for the replacement of the flex conduit. We stepped out of process mixing CM with PM
- No lift sheet
- No pre-job brief
- Management has not been successful in getting Maintenance to internalize Human Performance tool usage 100% of the time.
- No discussion of human performance tools when problem identified
- Skill-of-the-craft is accepted behavior 35 Enclosure 3 Corrective Actions
- Revised fleet procedures to define allowable work scope for minor maintenance, tool pouch work, and CR initiation.
- Maintenance personnel were trained using dynamic training methods.
- Implemented leadership action plan for Maintenance Superintendents. Accomplished with the assistance of leadership expert.
36 Enclosure 3 Conclusion and Wrap-Up
- The event is non-challenging as it does not meet the NUREG / CR 6850 criteria for challenging
- Tests revealed that the handswitch consistently fails at the same location, resulting in a self-extinguishing condition
- Target cables will not catch fire because heat rates are low.
- Modeling control room HVAC results in "green "
risk.*The event is not risk significant
- The event should be characterized as green