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
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.pdf LRA 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 Ventilation 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>>
1
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:
Prairie Island Nuclear Generating Plant ACRS License Renewal Subcommittee Meeting 1
Introductions
z Mike Wadley - Site Vice President z Gene Eckholt - License Renewal Project Manager z Steve Skoyen - Engineering Programs Manager z License Renewal Project Team and Subject Matter Experts 2
Agenda z Background z Operating History z Plant Description & Major Improvements z License Renewal Project z Renewed License Implementation z Specific Technical Items of Interest z Summary 3
=
Background===
z Plant Owner and Operator z Northern States Power - Minnesota (NSPM) z Subsidiary of Xcel Energy z Location z SE of Minneapolis-Saint Paul, MN z On Mississippi River 4
=
Background===
z Two 2 - Loop PWR Units z 1650 MWt z 575 MWe (Gross) per Unit z Westinghouse - NSSS z Pioneer Service & Engineering -
Architect/Engineer z Dual Containment Design z Steel Containment within Limited Leakage Concrete Shield Building (5 foot annulus) 5
=
Background===
z Once-Through Cooling Supplemented with Four Forced Draft Cooling Towers (Seasonal) z Ultimate Heat Sink is Mississippi River via Cooling Water System Site Layout Drawing 6
Operating History z Construction Permits Issued - June 1968 z Operating Licenses Issued z Unit 1 - August 1973 z Unit 2 - October 1974 z LRA Submitted - April 2008 7
Operating History z Unit 1 z Completed Refueling Outage 25 in Spring 2008 z Lifetime Capacity Factor 84.2%
z Cycle to Date Capacity Factor 96.6%
z Next Refueling Outage - Fall 2009 z Unit 2 z Completed Refueling Outage 25 in Fall 2008 z Lifetime Capacity Factor 86.5%
z Cycle to Date Capacity Factor 98.0%
z Next Refueling Outage - Spring 2010 8
Major Plant Improvements z 1983 - Constructed New Intake Screen House and Reconfigured Intake and Discharge Canals z 1986 & 1987 - Replaced Reactor Vessel Upper Internals z 1993 - Added Two New Diesel Generators to Unit 2 z Separated Units Electrically z Cooling Water Pump Upgraded to Safety Related to Provide Swing Backup to Diesel Cooling Water Pumps z 2004 - Replaced Unit 1 Steam Generators z Unit 2 Replacement is Planned z 2005 & 2006 Replaced Reactor Vessel Heads 9
License Renewal Project z Project Team z Scoping z Aging Management Reviews z Aging Management Programs z Aging Management Program Exceptions z Time Limited Aging Analyses z Commitments 10
License Renewal Project Team z LR Engineering Supervisors are NSP Employees z Extensive Plant Knowledge and Experience z Trained and Mentored by Other Plants with Renewed Licenses z Contract Support Staff has Significant LR Experience z Plant Subject Matter Experts Provided Support z Reviewed LRA Input Documents z Supported NRC LR Audits and Inspection z LR Project Team Engaged with Industry z NEI LR Task Force and Working Groups z Observed NRC LR Audits and Participated in LRA Peer Reviews at Other Plants 11
Scoping z Process Consistent with NEI 95-10 Rev 6 z Boundary Drawings Highlight Components for All Scoping Criteria z Switchyard Scoping Boundary Includes Breakers at Transmission System Voltage 12
Switchyard Scoping Boundary Spring Red Blue Red Byron Rock Lake Rock Creek
- 10 2 1 Bus 2 345kV 161kV 13.8kV Bus 1 Transmission System Plant System 1R CT12 Intake Training 2R Gen Gen 1CT Screen (U2) (U2) (U1) (U1)
(U1) (U2) House Center PINGP CLB Scope Expanded LR Scope per Proposed ISG 2008-01 Distribution 13
Aging Management Reviews z Aging Management Reviews Consistent with Guidance in NEI 95-10 z Maximized GALL Consistency to Extent Practical z 89.2% of AMR Line Items Consistent with GALL (Notes A-D) 14
Aging Management Programs z 43 Aging Management Programs z 29 Existing Programs z 14 New Programs z Program Consistency With GALL z 31 Programs Consistent with GALL (9 include Enhancements) z 10 Programs Consistent with Exceptions (6 also have Enhancements) z 2 Plant-Specific Programs 15
Typical AMP GALL Exceptions z Typical AMP GALL Exceptions Include the Use of:
z More Recent Revision of Industry Standard than Revision Cited in GALL z Different (or additional) Industry Standards z Alternatives to Performance Testing specified in GALL z Alternate Detection Techniques or More Recent NRC Guidance than GALL Recommends z Alternate to GALL Recommendations for Inspection/Test Frequency 16
Time-Limited Aging Analyses z TLAA Identification/Disposition Consistent with NUREG-1800 and NEI 95-10 z Evaluated In Accordance with 10 CFR 54.21(c)(1) 17
Commitment Management z 36 Regulatory Commitments for Future Action Resulting from LRA z Commitments are Tracked Through PINGP Commitment Tracking Program z Commitments have been Assigned to Station Personnel for Implementation Prior to PEO 18
Implementation z Implementation of LR Program is Responsibility of Engineering Programs Department z Implementation will be Managed under Formal Change Management Plan z All Aging Management Programs have Plant Owners z Engineering Staff has already been Augmented to Implement Renewed License Requirements 19
Specific Technical Items of Interest z Underground Medium Voltage Cables z SER Open Items z PWR Vessel Internals Program z Waste Gas Decay Tank Scoping z Refueling Cavity Leakage 20
Underground Medium Voltage Cables z Failure of Circ Water Pump Cable Caused Unit 1 Trip in May 2009 z Root Cause Evaluation and EPRI Testing of Cable in Progress z Plant has Experienced Few Other Cable Failures z Cable Insulation Testing Being Implemented in Inaccessible Medium Voltage Cables Not Subject to 10 CFR 50.49 Environmental Qualification Requirements Program 21
SER Open Item PWR Vessel Internals Program z GALL Anticipates Future PWR Vessel Internals Program z Specifies Commitment to Implement Program z As Part of Hearing Process the ASLB Admitted Contention that Commitment Alone was Insufficient z To Resolve Contention a Plant-Specific PWR Vessel Internals Program was Submitted 5/12/09 z Program is Based on EPRI MRP-227 Rev 0 (Dec. 2008) z ASLB has Dismissed Contention z NRC Staff Review in Progress 22
SER Open Item Waste Gas Decay Tank Scoping z 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 z PINGP Maintains WGDTs as Safety Related z WGDTs Not Initially in Scope Because Offsite Exposure Potential not Considered Comparable z WGDTs have been Reclassified as in LR Scope z LRA Scoping Changes were Submitted 6/5/2009 z NRC Staff Review in Progress 23
SER Open Item Refueling Cavity Leakage z NRC was Briefed on Refueling Cavity Leakage During Aging Management Audit z NRC has Reviewed Issue in Public Meeting, RAIs and Specific Site Audit of Documentation z NSPM has Responded to all NRC RAIs, Most Recently in Letter Dated June 24, 2009 z NRC Staff Review is in Progress 24
SER Open Item Refueling Cavity Leakage z Detailed Review of Issue Follows z Background on Leakage z Containment Configuration z Leak Locations & Leak Paths z Inspection Results to Date z Corrective Actions z Evaluation of Potential Degradation z Long Term Aging Management 25
Refueling Cavity Leakage
Background
z Intermittent Leakage Indications in Both Units Since Late 1980s z Leak Rate is 1-2 Gallons per Hour - Seen in ECCS Sump and Regenerative Heat Exchanger Room z Source is Refueling Cavity Based on:
z Leakage Indications Typically Begin 2 - 4 Days After Refueling Cavity Flood and End Approximately 3 days After Cavity is Drained.
z Chemistry Indicates Refueling Water z Sealing Methods Have Been Successful, but not Consistently 26
Refueling Cavity Leakage
Background
z Root Cause Evaluation was Performed Following Most Recent Outage z Sources of Leakage were Determined to be Embedment Plates for Reactor Internals Stands and Rod Control Cluster Change Fixture 27
Refueling Cavity Leakage Containment Design Containment Vessel z Steel Containment Vessel z 1-1/2 inch Thick Bottom Head, 1-1/2 inch Shell, 3/4 inch Top Head z 3-1/2 inch Thick at ECCS Sump (sump B) Penetrations z SA-516-70 Low Temperature Carbon Steel z Provides Primary Containment z Lower Head Encased in Concrete z 5 foot Annular Gap Between Containment Vessel and Limited Leakage Reinforced Concrete Shield Building Containment Elevation 28
Refueling Cavity Leakage Leakage Seen in Path ECCS Sump and in Regenerative HX Room (below cavity)
Cavity Photo from NW Cavity Photo Overhead Containment Elevation
Refueling Cavity Leakage Leak Locations Typical Reactor Vessel Internals Stand Support Typical RCC Change Fixture Support 30
Refueling Cavity Leakage Leak Locations Base Plate Embedment Plate Existing 1/4" thk stainless steel cavity liner Existing cavity liner Side View fillet weld to Existing seal weld to embedment plate embedment plate not accessible. Failure of weld would result in leak.
General Arrangement of Change Fixture Supports 31
Refueling Cavity Leakage Path z Path to ECCS Sump z Under Refueling Cavity Liner Through Construction Joint Between Floor of Transfer Pit and Wall Behind Fuel Transfer Tube to Inner Wall of Containment Vessel z Travels Down and Horizontally, Between Containment Vessel and Concrete, to Low Point of Containment Vessel Bottom Head z Seeps Through Grout in ECCS Sump z Path to Regenerative Heat Exchanger Room z Once Under Liner, Follows Cracks in the Concrete, Seeping Through the Ceiling and Walls of the Regenerative HX Room ECCS Sump 32
Origin Regen HX ECCS Sump C Sump Room Fuel Transfer Tube Leak Paths 33
Refueling Cavity Leakage Inspection Results to Date z Ultrasonic and Visual Examinations of Containment Vessel z ECCS Sump z Grout Removed z Wall Thickness Measurements at or Above Nominal Sump Section z No Corrosion Identified.
z Annulus z Wall Thickness Measurements at or Above Nominal Annulus Photo z No Corrosion Identified 34
Refueling Cavity Leakage Corrective Actions - Repairs z Perform Repairs to Eliminate Leakage During Next Refueling Outage of Each Unit z Unit 1 - September 2009 z Unit 2 - April 2010 35
Refueling Cavity Leakage Corrective Actions - Repair Method Replace existing nuts with fabricated blind nuts seal New seal weld between welded to baseplate. baseplate and embedment plate.
Existing 1/4" thk stainless steel cavity liner Existing cavity liner Side View fillet weld to Existing seal weld to embedment plate embedment plate not accessible. Failure of weld would result in leak.
36
Refueling Cavity Leakage Corrective Actions - Monitoring & Assessment z Enhance Monitoring by Removing Concrete from Sump Below Reactor Vessel to Expose Containment Vessel z Next Outages Following Refueling Cavity Repairs z Inspect (VT and UT) Containment Vessel and Assess Concrete z Evacuate any Water Observed z Additional Assessment z Margin Assessment of Containment Vessel, Concrete and Rebar z Evaluate Structural Requirements and Potential Degradation in Concrete Around Transfer Tube 37
Refueling Cavity Leakage Evaluation of Potential Degradation z Evaluations have been performed for potential degradation of:
z Steel Containment Vessel z Concrete z Rebar 38
Refueling Cavity Leakage Evaluation of Potential Degradation z Steel Containment Vessel z No Corrosion has been Identified z Water is Essentially Stagnant - Oxygen Would be Consumed to Preclude Continued Corrosion z Alkalinity from the Concrete Would Elevate pH to Inhibit Corrosion in Wetted Areas z Containment Vessel Corrosion Behind Concrete in Areas Wetted by Refueling Cavity Leakage Would be no More than 10 mils 39
Refueling Cavity Leakage Evaluation of Potential Degradation z Concrete z Long Term Exposure to Acid can Dissolve CaOH in Cement Binder and Soluble Aggregate z Dissolving CaOH Neutralizes Acid if not Refreshed.
z At Refueling Cavity Liner z Evaluation Concluded Negligible Effect on Refueling Cavity Walls and Floor z Concrete at Transfer Tube End Still Being Evaluated Since Thickness <1 foot.
40
Refueling Cavity Leakage Evaluation of Potential Degradation z Concrete (Contd) z At Containment Vessel Inside Surface z Water is Essentially Stagnant so Acid Would be Neutralized by Alkalinity in Concrete with Minimal Effect z At Cracks z Water is Essentially Stagnant so Acid Would be Neutralized by Alkalinity in Concrete with Minimal Effect 41
Refueling Cavity Leakage Evaluation of Potential Degradation z Rebar z Some Potential for Refueling Cavity Leakage to Reach Rebar in Cracks z Corrosion of Wetted Rebar is Inhibited by Alkalinity (CaOH) of Concrete, Which Promotes Protective Layer z Qualitative Assessment Concludes There Have Been no Significant Signs of Rebar Corrosion z Corrosion of Rebar, Whether Wetted Periodically or Continuously, Would be Minimal 42
Refueling Cavity Leakage Evaluation of Potential Degradation z Conclusions z Expected Containment Vessel Corrosion Behind Concrete in Areas Wetted by Refueling Cavity Leakage is Minimal z Concrete Degradation or Rebar Corrosion Would not have had a Significant Effect on Reinforced Concrete That Has Been Wetted by Refueling Cavity Leakage 43
Refueling Cavity Leakage Long Term Aging Management z Monitor Areas Previously Exhibiting Leakage for Next Two Outages After Repairs to Confirm That Leakage has not Recurred z Continue General Monitoring for New Leakage Using Structures Monitoring Program and ASME Section XI Subsection IWE Program for Remainder of Plant Life z Utilize Corrective Action Program for Evaluation and Correction of New Issues 44
Summary z LRA Developed by Experienced Team z LRA Conforms to Regulatory Requirements and Follows Industry Guidance z PINGP Will Be Prepared to Manage Aging During the Period of Extended Operation 45
Questions?
46
Backup Slides 47
Plant Electrical Distribution 345kV Transmission 161kV 345kV 13.8kV (#10)
System 2R Plant 1CT Intake System Screen 34.5kV House Switchyard Fence 2RY 2RX 1R 13.8kV X Y Non-Safety Related Buses CT11 CT12 Cooling Tower 4kV Safety Related 4kV Unit 2 Unit 1 Cooling Tower Substation PINGP CLB Scope Expanded LR Scope per Proposed ISG 2008-01 48
Aging Management Programs z Programs with Exceptions to GALL z Bolting Integrity Program z Closed-Cycle Cooling Water System Program z Compressed Air Monitoring Program z Electrical Cable Connections (E6) Program z Fire Protection Program z Flow-Accelerated Corrosion Program z Fuel Oil Chemistry Program z Selective Leaching of Materials Program z Steam Generator Tube Integrity Program z Water Chemistry Program 49
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.
50
ECCS Sump Showing Grout To 31 To 34 51
53