ML091900057
| ML091900057 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 07/01/2009 |
| From: | - No Known Affiliation |
| To: | Division of License Renewal |
| References | |
| Download: ML091900057 (54) | |
Text
1 PrairieIslandNPEm Resource From: Eckholt, Gene F. [Gene.Eckholt@xenuclear.com]
Sent: Wednesday, July 01, 2009 4:26 PM To:Plasse, Richard
Subject:
FW: ACRS Presentation - DRAFT 7-1-09A Attachments:
ACRS Presentation - DRAFT 7-1-09A.pdfLRA Adds based on our response to NRC RAIs:
Abandoned equipment that is not disconnected and drained was added to the scope of License Renewal (RAI 2.1-2)
Steam Generator Blowdown Hold-up Tank Filters and interconnected piping and valves Reactor Building Heating Components and interconnected piping and valves.
Floor drains for fire fighting water (RAI 2.3.3.9-2)
Fire Damper in the Control Room and Miscellaneous Area Ventilation System (RAI 2.3.3.5-02)
Flexible connections (EPDM) in the Turbine and Administration Building Ventilati on System (RAI 2.3.3.5-04)
Flexible connections (Stainless Steel) in the Heating System (RAI 2.3.3.11-01)
Flexible Connections (Stainless Steel) in the Diesel Generator and Support System (RAI 3.3.2-8-1)
Piping, valves and sight glasses exposed to waste oil in the Diesel Generator and Support System (RAI B2.19.1)
Waste Gas Decay Tanks and interconnected piping and valves (Open Item 2.1.4.1.2-01)
Boundary drawings corrections were noted where in scope components (pipe, fittings, fan motors, etc.) were inadvertently shown out of scope. The components were typically already addressed in the LRA tables and therefore no LRA changes were required.
<<ACRS Presentation - DRAFT 7-1-09A.pdf>>
Hearing Identifier: Prairie_Island_NonPublic Email Number: 1071 Mail Envelope Properties (7A9B2084CC9CEC45828E829CBF20D638033F6DB1)
Subject:
FW: ACRS Presentation - DRAFT 7-1-09A Sent Date: 7/1/2009 4:25:48 PM Received Date: 7/1/2009 4:25:54 PM From: Eckholt, Gene F.
Created By: Gene.Eckholt@xenuclear.com Recipients: "Plasse, Richard" <Richard.Plasse@nrc.gov>
Tracking Status: None
Post Office: enex02.ft.nmcco.net Files Size Date & Time MESSAGE 1277 7/1/2009 4:25:54 PM ACRS Presentation - DRAFT 7-1-09A.pdf 875773 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:
1 Prairie Island Nuclear Generating Plant ACRS License Renewal Subcommittee Meeting 2 IntroductionsMike Wadley -Site Vice PresidentGene Eckholt -License Renewal Project ManagerSteve Skoyen -Engineering Programs Manager License Renewal Project Team and Subject
Matter Experts 3 Agenda Background Operating History Plant Description & Major Improvements License Renewal Project Renewed License Implementation Specific Technical Items of Interest Summary 4 Background Plant Owner and OperatorNorthern States Power -Minnesota (NSPM) Subsidiary of Xcel Energy Location SE of Minneapolis-Saint Paul, MN On Mississippi River 5 BackgroundTwo 2 -Loop PWR Units 1650 MW t 575 MW e (Gross) per UnitWestinghouse -NSSS Pioneer Service & Engineering -
Architect/Engineer Dual Containment Design Steel Containment within Limited Leakage Concrete Shield Building (5 foot annulus) 6 Background Once-Through Cooling Supplemented with Four Forced Draft Cooling Towers (Seasonal) Ultimate Heat Sink is Mississippi River via
Cooling Water System Site Layout Drawing 7 Operating HistoryConstruction Permits Issued -June 1968 Operating Licenses IssuedUnit 1 -August 1973Unit 2 -October 1974LRA Submitted -April 2008 8 Operating History Unit 1 Completed Refueling Outage 25 in Spring 2008 Lifetime Capacity Factor 84.2% Cycle to Date Capacity Factor 96.6%Next Refueling Outage -Fall 2009 Unit 2 Completed Refueling Outage 25 in Fall 2008 Lifetime Capacity Factor 86.5% Cycle to Date Capacity Factor 98.0%Next Refueling Outage -Spring 2010 9 Major Plant Improvements1983 -Constructed New Intake Screen House and Reconfigured Intake and Discharge Canals1986 & 1987 -Replaced Reactor Vessel Upper Internals1993 -Added Two New Diesel Generators to Unit 2 Separated Units Electrically Cooling Water Pump Upgraded to Safety Related to Provide Swing Backup to Diesel Cooling Water Pumps2004 -Replaced Unit 1 Steam Generators Unit 2 Replacement is Planned 2005 & 2006 Replaced Reactor Vessel Heads 10 License Renewal Project Project Team Scoping Aging Management Reviews Aging Management Programs Aging Management Program Exceptions Time Limited Aging Analyses Commitments 11 License Renewal Project Team LR Engineering Supervisors are NSP Employees Extensive Plant Knowledge and Experience Trained and Mentored by Other Plants with Renewed Licenses Contract Support Staff has Significant LR Experience Plant Subject Matter Experts Provided Support Reviewed LRA Input Documents Supported NRC LR Audits and Inspection LR Project Team Engaged with Industry NEI LR Task Force and Working Groups Observed NRC LR Audits and Participated in LRA Peer Reviews at Other Plants 12 Scoping Process Consistent with NEI 95-10 Rev 6 Boundary Drawings Highlight Components for All Scoping Criteria Switchyard Scoping Boundary Includes
Breakers at Transmission System Voltage 13 Switchyard Scoping Boundary 1R(U1)CT12(U2)IntakeScreenHouseTrainingCenter 2R(U2)Gen (U1)1CT (U1)SpringCreekByronRedRock 1 Gen(U2)Blue LakeRedRock 2161kV13.8kV 345kV Bus 1 Bus 2#10TransmissionSystemPlantSystemPINGP CLB ScopeExpanded LR Scope per Proposed ISG 2008-01Distribution 14 Aging Management Reviews Aging Management Reviews Consistent with Guidance in NEI 95-10 Maximized GALL Consistency to Extent
Practical 89.2% of AMR Line Items Consistent with GALL (Notes A-D) 15 Aging Management Programs 43 Aging Management Programs 29 Existing Programs 14 New Programs Program Consistency With GALL 31 Programs Consistent with GALL (9 include Enhancements) 10 Programs Consistent with Exceptions
(6 also have Enhancements) 2 Plant-Specific Programs 16 Typical AMP GALL Exceptions Typical AMP GALL Exceptions Include the Use of: More Recent Revision of Industry Standard than Revision Cited in GALL Different (or additional) Industry Standards Alternatives to Performance Testing specified in GALL Alternate Detection Techniques or More Recent NRC Guidance than GALL Recommends Alternate to GALL Recommendations for Inspection/Test Frequency 17 Time-Limited Aging Analyses TLAA Identification/Disposition Consistent with NUREG-1800 and NEI 95-10 Evaluated In Accordance with 10 CFR
54.21(c)(1) 18 Commitment Management 36 Regulatory Commitments for Future Action Resulting from LRA Commitments are Tracked Through PINGP
Commitment Tracking Program Commitments have been Assigned to Station
Personnel for Implementation Prior to PEO 19 Implementation Implementation of LR Program is Responsibility of Engineering Programs Department Implementation will be Managed under Formal
Change Management Plan All Aging Management Programs have Plant
Owners Engineering Staff has already been Augmented to Implement Renewed License Requirements 20 Specific Technical Items of Interest Underground Medium Voltage Cables SER Open Items PWR Vessel Internals Program Waste Gas Decay Tank Scoping Refueling Cavity Leakage 21 Underground Medium Voltage Cables Failure of Circ Water Pump Cable Caused Unit 1 Trip in May 2009 Root Cause Evaluation and EPRI Testing of Cable in Progress Plant has Experienced Few Other Cable Failures Cable Insulation Testing Being Implemented in Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Program 22 SER Open Item PWR Vessel Internals Program GALL Anticipates Future PWR Vessel Internals Program Specifies Commitment to Implement Program As Part of Hearing Process the ASLB Admitted
Contention that Commitment Alone was Insufficient To Resolve Contention a Plant-Specific PWR Vessel Internals Program was Submitted 5/12/09 Program is Based on EPRI MRP-227 Rev 0 (Dec. 2008) ASLB has Dismissed Contention NRC Staff Review in Progress 23 SER Open Item Waste Gas Decay Tank Scoping SSC are in Scope per 10 CFR 54.4.a(1) if, in part, they Prevent or Mitigate the Consequences of Accidents
Which Could Result in Offsite Exposures "Comparable"
to Those Referred to in 10 CFR 100.11 PINGP Maintains WGDTs as Safety Related WGDTs Not Initially in Scope Because Offsite Exposure Potential not Considered "Comparable" WGDTs have been Reclassified as in LR Scope LRA Scoping Changes were Submitted 6/5/2009 NRC Staff Review in Progress 24 SER Open Item Refueling Cavity Leakage NRC was Briefed on Refueling Cavity Leakage During Aging Management Audit NRC has Reviewed Issue in Public Meeting, RAIs and Specific Site Audit of Documentation NSPM has Responded to all NRC RAIs, Most
Recently in Letter Dated June 24, 2009 NRC Staff Review is in Progress 25 SER Open Item Refueling Cavity Leakage Detailed Review of Issue Follows Background on Leakage Containment Configuration Leak Locations & Leak Paths Inspection Results to Date Corrective Actions Evaluation of Potential Degradation Long Term Aging Management 26 Refueling Cavity Leakage Background Intermittent Leakage Indications in Both Units Since Late 1980s Leak Rate is 1-2 Gallons per Hour -Seen in ECCS
Sump and Regenerative Heat Exchanger Room Source is Refueling Cavity Based on:Leakage Indications Typically Begin 2 -4 Days After Refueling Cavity Flood and End Approximately 3 days After Cavity is Drained. Chemistry Indicates Refueling Water Sealing Methods Have Been Successful, but not
Consistently 27 Refueling Cavity Leakage Background Root Cause Evaluation was Performed Following Most Recent Outage Sources of Leakage were Determined to be Embedment Plates for Reactor Internals
Stands and Rod Control Cluster Change Fixture 28 Refueling Cavity Leakage Containment Design Containment Vessel Steel Containment Vessel 1-1/2 inch Thick Bottom Head, 1-1/2 inch Shell, 3/4 inch Top Head 3-1/2 inch Thick at ECCS Sump (sump B) Penetrations SA-516-70 Low Temperature Carbon Steel Provides Primary Containment Lower Head Encased in Concrete 5 foot Annular Gap Between Containment Vessel and Limited Leakage Reinforced
Concrete Shield Building Containment Elevation Refueling Cavity Leakage Path Cavity Photo Overhead Cavity Photo from NW Leakage Seen in ECCS Sump and in Regenerative HX Room (below cavity)
Containment Elevation 30 Refueling Cavity Leakage Leak Locations Typical Reactor Vessel Internals Stand Support Typical RCC Change Fixture Support 31 Refueling Cavity Leakage Leak Locations Existing cavity liner fillet weld to embedment plate General Arrangement of Change Fixture Supports Existing seal weld to embedment plate not accessible. Failure of weld would result in leak.Embedment Plate Side View Base Plate Existing 1/4" thk stainless steel cavity liner 32 Refueling Cavity Leakage Path Path to ECCS Sump Under Refueling Cavity Liner Through Construction Joint Between Floor of Transfer Pit and Wall Behind Fuel Transfer Tube to Inner Wall of Containment Vessel Travels Down and Horizontally, Between Containment Vessel and Concrete, to Low Point of Containment Vessel
Bottom HeadSeeps Through Grout in ECCS Sump Path to Regenerative Heat Exchanger Room Once Under Liner, Follows Cracks in the Concrete, Seeping Through the Ceiling and Walls of the Regenerative HX RoomECCS Sump 33Origin ECCS Sump Sump CFuel Transfer TubeRegenHX Room Leak Paths 34 Refueling Cavity Leakage Inspection Results to Date Ultrasonic and Visual Examinations of Containment Vessel ECCS Sump Grout Removed Wall Thickness Measurements at or Above Nominal No Corrosion Identified. Annulus Wall Thickness Measurements at or Above Nominal No Corrosion IdentifiedSump SectionAnnulu sPhoto 35 Refueling Cavity LeakageCorrective Actions -Repairs Perform Repairs to Eliminate Leakage During Next Refueling Outage of Each UnitUnit 1 -September 2009Unit 2 -April 2010 36 Refueling Cavity LeakageCorrective Actions -Repair Method Existing 1/4" thk stainless steel cavity liner New seal weld between baseplate and embedment
plate.Existing cavity liner fillet weld to embedment plate Existing seal weld to embedment plate not accessible. Failure of weld would result in leak.
Replace existing nuts with fabricated blind nuts seal welded to baseplate.
Side View 37 Refueling Cavity LeakageCorrective Actions -Monitoring & Assessment Enhance Monitoring by Removing Concrete from Sump Below Reactor Vessel to Expose
Containment Vessel Next Outages Following Refueling Cavity Repairs Inspect (VT and UT) Containment Vessel and Assess Concrete Evacuate any Water Observed Additional Assessment Margin Assessment of Containment Vessel, Concrete and Rebar Evaluate Structural Requirements and Potential
Degradation in Concrete Around Transfer Tube 38 Refueling Cavity Leakage Evaluation of Potential Degradation Evaluations have been performed for potential degradation of: Steel Containment Vessel Concrete Rebar 39 Refueling Cavity Leakage Evaluation of Potential Degradation Steel Containment Vessel No Corrosion has been Identified Water is Essentially Stagnant -Oxygen Would be Consumed to Preclude Continued Corrosion Alkalinity from the Concrete Would Elevate pH
to Inhibit Corrosion in Wetted Areas Containment Vessel Corrosion Behind
Concrete in Areas Wetted by Refueling Cavity
Leakage Would be no More than 10 mils 40 Refueling Cavity Leakage Evaluation of Potential Degradation Concrete Long Term Exposure to Acid can Dissolve CaOH in Cement Binder and Soluble Aggregate Dissolving CaOH Neutralizes Acid if not Refreshed. At Refueling Cavity Liner Evaluation Concluded Negligible Effect on Refueling Cavity Walls and FloorConcrete at Transfer Tube End Still Being Evaluated
Since Thickness <1 foot.
41 Refueling Cavity Leakage Evaluation of Potential Degradation Concrete (Cont'd) At Containment Vessel Inside Surface Water is Essentially Stagnant so Acid Would be Neutralized by Alkalinity in Concrete with Minimal Effect At Cracks Water is Essentially Stagnant so Acid Would be Neutralized by Alkalinity in Concrete with Minimal Effect 42 Refueling Cavity Leakage Evaluation of Potential Degradation Rebar Some Potential for Refueling Cavity Leakage to Reach Rebar in Cracks Corrosion of Wetted Rebar is Inhibited by Alkalinity (CaOH) of Concrete, Which Promotes
Protective Layer Qualitative Assessment Concludes There Have Been no Significant Signs of Rebar Corrosion Corrosion of Rebar, Whether Wetted Periodically or Continuously, Would be Minimal 43 Refueling Cavity Leakage Evaluation of Potential Degradation Conclusions Expected Containment Vessel Corrosion Behind Concrete in Areas Wetted by Refueling Cavity
Leakage is Minimal Concrete Degradation or Rebar Corrosion Would
not have had a Significant Effect on Reinforced Concrete That Has Been Wetted by Refueling Cavity Leakage 44 Refueling Cavity Leakage Long Term Aging Management Monitor Areas Previously Exhibiting Leakage for Next Two Outages After Repairs to Confirm That
Leakage has not Recurred Continue General Monitoring for New Leakage Using Structures Monitoring Program and ASME Section XI Subsection IWE Program for
Remainder of Plant Life Utilize Corrective Action Program for Evaluation and Correction of New Issues 45 Summary LRA Developed by Experienced Team LRA Conforms to Regulatory Requirements and Follows Industry Guidance PINGP Will Be Prepared to Manage Aging
During the Period of Extended Operation 46 Questions?
47 Backup Slides 48 Plant Electrical Distribution X 1RCT12 2R1CT161kV13.8kV (#10) 345kVTransmissionSystemPlantSystemCooling TowerCT112RX2RYIntakeScreenHouseUnit 2Unit 1Cooling Tower SubstationSwitchyard Fence Y 345kV13.8kVNon-Safety Related Buses 4kVSafetyRelated 4kV 34.5kVPINGP CLB ScopeExpanded LR Scope per Proposed ISG 2008-01 49 Aging Management Programs Programs with Exceptions to GALL Bolting Integrity Program Closed-Cycle Cooling Water System Program Compressed Air Monitoring Program Electrical Cable Connections (E6) Program Fire Protection Program Flow-Accelerated Corrosion Program Fuel Oil Chemistry Program Selective Leaching of Materials Program Steam Generator Tube Integrity Program Water Chemistry Program 50 Shield Building Annulus UT exam of containment
vessel from annulus was performed.
Scanned 18'long x 2'high area with all readings
above 1.5 inch nominal plate thickness.