ML070380543
ML070380543 | |
Person / Time | |
---|---|
Site: | Pilgrim |
Issue date: | 01/29/2007 |
From: | Douglas E Entergy Corp |
To: | Buckberg P H NRC/NRR/ADRO/DLR |
References | |
TAC 3698 | |
Download: ML070380543 (26) | |
Text
Perry Buckberg -FW: Pilgrim LRA Amendment 13 P~age t1I From: "Ellis, Douglas" <dellisl @entergy.com>
To: "Perry Buckberg" <PHB1 @nrc.gov>Date: 1/29/2007 2:31:17 PM
Subject:
FW: Pilgrim LRA Amendment 13 Perry -hard copy to follow in U.S. Mail. If possible please docket the amendment on or by tomorrow, 1/30. Thank you, Doug Ellis, Pilgrim Licensing.
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Creation Date From: Created By: FW: Pilgrim LRA Amendment 13 1/29/2007 2:30:31 PM"Ellis, Douglas" <dellis 1 @entergy.com>
dellis 1 @entergy.com Recipients nrc.gov OWGWPO01 .HQGWDO01 PHB 1 (Perry Buckberg)Post Office OWGWPOO I.HQGWDOOI Route nrc.gov Files MESSAGE ScanOOl.PDF Mime.822 Options Expiration Date: Priority: ReplyRequested:
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Concealed Subject;Security: Size 708 1650280 2261317 None Standard No None Date & Time 1/29/2007 2:30:31 PM No -_Standard Junk Mail Handling Evaluation Results Message is eligible for Junk Mail- handling This message was not classified as Junk Mail Junk Mail settings when this message was delivered Junk Mail handling disabled by User Junk Mail handling disabled by Administrator Junk List is not enabled Junk Mail using personal address books is not enabled Block List is not enabled Entergy Nuclear Operations, inc.Z Pilgrim Stadion 600 Rocky Hill Road Plymouth.
MA 02360 Stephen J. Bethay Director, Nucear ,smess. "m January 29, 2007 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Entergy Nuclear Operations, Inc.Pilgrim Nuclear Power Station Docket No. 50-293 License No. DPR-35 License Renewal Application Amendment 13
REFERENCE:
Entergy letter, License Renewal Application, dated January 25, 2006 (2.06.003)
LETTER NUMBER: 2.07.010
Dear Sir or Madam:
In the referenced letter, Entergy Nuclear Operations, Inc. applied for renewal of the Pilgrim Station operating license. NRC TAC NO. MC9669 was assigned to the application., This License Renewal Application (LRA) amendment consists of three attachments stemming from a conference call on January 23, 2007 with the NRC license renewal staff. Attachment A contains the list of revised regulatory commitments.
Attachment B contains clarifying information on the Drywell shell and supersedes the information in LRA Amendment 1 and LRA Amendment 2 in their entirety.
Attachment C contains changes to the LRA.Please contact Mr. Bryan Ford, (508) 830-8403, if you have any questions regarding this subject.I declare under penalty of perjury.that the foregoing is true and correct. Executed on January Z, 2007.Sincerely, Stepen J moethay Director, Nuclear Safety Assessment DWE/dl Attachments: (as stated)cc: see next page Entergy Nuclear Operations, Inc.Pilgrim Nuclear Power Station Letter Number: 2.07.010 Page 2 cc: with Attachments Mr. Perry Buckberg Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Alicia Williamson Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Susan L. Uttal, Esq.Office of the General Counsel U.S. Nuclear Regulatory Commission Mail Stop 0-15 D21 Washington, DC 20555-0001 Sheila Slocum Hollis, Esq.Duane Morris LLP 1667 K Street N.W., Suite 700 Washington, DC 20006 cc: without Attachments Mr. Joseph Rogers Commonwealth of Massachusetts Assistant Attorney General Division Chief, Utilities Division 1 Ashburton Place Boston, MA 02108 Mr. Matthew Brock, Esq.Commonwealth of Massachusetts Assistant Attorney General Environmental Protection Division One Ashburton Place Boston, MA 02108 Diane Curran, Esq.Harmon, Curran, and Eisenberg, L.L.P.1726 M Street N.W., Suite 600 Washington, DC 20036 Molly H. Bartlett, Esq.52 Crooked Lane Duxbury, MA 02332 Mr. James Kim Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission,,, Washi ngt!,1DC"205550001.
Mr. Jack Strosnider, Director Office of Nuclear Material and Safeguards U.S. Nuclear Regulatory Commission Washington, DC 20555-00001 Mr. Samuel J. Collins, Administrator Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 NRC Resident Inspector Pilgrim Nuclear Power Station-Mr. Robert Walker,,Director..
Massachusetts Department of Public,.Health ti',.:'.uý.-r m-, Radiation Control Program Schrfft enter,"1Suite 1 M2A: 529 Main Street Charlestown, MA 02129 Mr. Ken McBride, Director Massachusetts Emergency Management Agency 400 Worchester Road Framingham, MA 01702 Mr. James E. Dyer, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-00001 ATTACHMENT A to Letter 2.07.010 (9 pages)Revised List of Regulatory Commitments C 4r I'-~ -i r -
Revised List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document.Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
- COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section NoJ Comments 1 Implement the Buried Piping and Tanks Inspection June 8, 2012 Letters B.1.2 / Audit Program as described in LRA Section B.1.2. 2.06.003 Item 320 and 2.06.057 2 Enhance the implementing procedure for ASME June 8, 2012 Letters B.1.6/tAudit Section XI inservice inspection and testing to specify 2.06.003 Item 320 that the guidelines in Generic Letter 88-01 or and approved BWRVIP-75 shall be considered in 2.06.057 determining sample expansion if indications are found in Generic Letter 88-01 welds.3 Inspect fifteen (15) percent of the top guide locations As stated in the Letters B.1.8./Audit using enhanced visual inspection technique, EVT-1, commitment.
2.06.003 Items 155, within the first 18 years of the period of extended and 320 ,operation, with at leastýone-third of the inspections to 2.06.057 be completed within the first six (6) years and at least and two-thirds within the first 12 years of the period of 2.06.064 extended operations.
Locations selected for and examination will be areas that have exceeded the 2.06.081 neutron fluence threshold.
._____,.4 Enhance the Diesel Fuel Monitoring Program to June 8, 2012 Letters B.1.10/include, quarterly sampling of. the security diesel..,,;
2.06.003-Audit'. generator fuel storage tank.. -Particulates (filterable
.-and .solids), water and sediment checks will be performed
.06.057'on the samples.'.
Filterable solids acceptance6criteria and .'will be = 10 mg/l. Waterand sediment acceptance 2.06.089 I.k:-criteria will be = 0.05%. __,_____...._ -r , 5 Enhance the Diesel Fuel Monitoring Program to June 8, 2012 Letters B.1.10/install instrumentation to monitor for leakage between 2.06.003 Audit Items the two walls of the security diesel generator fuel and 155, 320 storage tank to ensure that significant degradation is 2.06.057 not occurring.
6 Enhance the Diesel Fuel Monitoring Program to June 8, 2012 Letters B.1.10/specify acceptance criterion for UT measurements of 2.06.003 Audit Items emergency diesel generator fuel storage tanks and 165, 320 (T-126A&B).
2.06.057 I COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section NoJ Comments 7 Enhance Fire Protection Program procedures to state June 8, 2012 Letters B.1.13.1 /that the diesel: engine sub-systems (including the fuel 2.06.003 Audit Items supply line) shall be observed while the pump is and 320, 378 running. Acceptance criteria will be enhanced to 2.06.057 verify that the diesel engine did not exhibit signs of and degradation while it was running; such as fuel oil, 2.06.064 lube oil, coolant, or exhaust gas leakage. Also, enhance procedures to clarify that the diesel-driven fire pump engine is inspected for evidence of corrosion in the intake air, turbocharger, and jacket water system components as well as lube oil cooler.The jacket water heat exchanger is inspected for evidence of corrosion or buildup to manage loss of material and fouling on the tubes. Also, the engine exhaust piping and silencer are inspected for evidence of internal corrosion or cracking.8 Enhance the Fire Protection Program procedure for June 8, 2012 Letters B.1.13.1 I Halon system functional testing to state that the 2.06.003 Audit Item Halon 1301 flex hoses shall be replaced if leakage and 320... .. occurs during the system functional-test.
-. ... .. ....... 2.06.057 .. .... ....9 Enhance Fire Water System Program procedures to June 8, 2012 Letters B.1.13.2/include inspection of hose reels for corrosion.
2.06.003 Audit Item Acceptance criteria will be enhanced to verify no and 320 significant corrosion.
2.06.057 , Enhance the FireWater System Program.to state that ,.June 8, 2012 .Letters.
B .1.13.2/a sample of sprinkler heads will be inspected using 2.06.003 Audit Item guidance of NFPA 25 (2002 aLntdSec 320 T guidanc Eii-)sco 2- 06'057,
.1:1li INFPA 25 al-s'6 taih .b repeat ...',i "". "*"26 ;0 .' }.:-':..:-f!?, 'i' .~this sampling every 10 Qer~fe initilfed.service-.,41.t 6.ti n". " " 11 Enhance the Fire Water System m 'to state:that June..8,.2012 Letters B.1.13.2 /wall thickness evaluations of fire protection piping will _,, 2.06.003 Audit Item be performed on system components using non- and 320 intrusive techniques (e.g., volumetric testing) to 2.06.057 identify evidence of loss of material due to corrosion.
These Inspections will be per-flormed before the end of the current operating term and at intervals thereafter during the period of extended operation.
Results of the initial evaluations will be used to determine the appropriate inspection interval to ensure aging effects are identified prior to loss of intended function.12 Implement the Heat Exchanger Monitoring Program June 8, 2012 Letters B.1.15 /as described in LRA Section B.1.15. 2.06.003 Audit Item and 320 2.06.057 2
- COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 13 Enhance the Instrument Air Quality Program to June 8, 2012 Letters B.1.17 /include a sample point in the standby gas treatment 2.06.003 Audit Item and torus vacuum breaker instrument air subsystem and 320 in addition to the instrument air header sample points. 2.06.057'14 Implement the Metal-Enclosed Bus Inspection June 8, 2012 Letters B.1.18/Program as described in LRA Section B.1.18. 2.06.003 Audit Item and 320 2.06.057 15 Implement the Non-EQ Inaccessible Medium-Voltage June 8, 2012 Letters B.1.19 /Cable Program as described in LRA Section B.1.19. 2.06.003 Audit items Include developing a formal procedure to inspect and 311,320 manholes for in-scope medium voltage cable. _2.06.057 16 Implement the Non-EQ Instrumentation Circuits Test June 8, 2012 Letters B.1.20 /Review Program as described in LRA Section B.1.20. 2.06.003 Audit Item and 320____ ___ ____ ____ 2.06.057 17 Implement the Non-EQ Insulated Cables and June 8, 2012 Letters B.1.21/..Connections Program.as.described in LRA Section -2.06.003 Audit Item.B.1.21. and 320 1_ 2.06.057 18 Enhance the Oil Analysis Program to periodically June 8, 2012 Letters B. 1.22 I change CRD pump lubricating oil. A particle count 2.06.003 Audit Item and check for water wilL be performed on the drained and 320 oil to detect wear rates, 2.06.057_ ',;'; contamination by moisture'or, excessive corrosion..,..
1 ':- r , 1 ,' dnhance'Oil Analysis'rbograr procedures,,f.or, ...,,June'&8:2 12 !Letters.,-'
-, 1-.2-2 t/",:security diesel and reactor water cleanuppump i ., ,.206:003..
'.A t,A;Item..
"..chan"ges to obtain oil samplesfOorm-the drained oil. and 320'Procedures for lubricating oil analysis will be .. 2.06057..enhanced to specify that a particle count and check for water are performed on oil samples from the fire water pump diesel, security diesel, and reactor water cleanup pumps.20 Implement the One-Time Inspection Program as June 8, 2012 Letters B62.23 /described in LRA Section B.1.23. This includes 2.06.003 Audit Items destructive or non-destructive examination of one (1) and 219, 320 socket welded connection using techniques proven 2.06.057 by past industry experience to be effective for the identification of cracking in small bore socket welds.Should an inspection opportunity not occur (e.g., socket weld failure or socket weld replacement), a susceptible small-bore socket weld will be examined either destructively or non-destructively prior to entering the period of extended operation.
3 COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 21 Enhance the Periodic Surveillance and Preventive June 8, 2012 Letters B.1.24 /Maintenance Program as necessary to assure that 2.06.003 Audit Item the effects of aging will be managed as described in and 320__LRA Section B. 1.24. 2.06.057 22 Enhance the Reactor Vessel Surveillance Program to June 8, 2012 Letters B.1.26 /proceduralize the data analysis, acceptance criteria, 2.06.003 Audit Item and corrective actions described in LRA Section and 320 B.1.26. 2.06.057 23 Implement the Selective Leaching Program in June 8, 2012 Letters B.1.27 /accordance with the program as described in LRA 2.06.003 Audit Item Section B. 1.27. and 320 2.06.057 24 Enhance the Service Water Integrity Program June 8, 2012 Letters 6.1.28 /procedure to clarify that heat transfer test results are 2.06.003 Audit Item trended. and 320___2.06.057 25 Enhance the Structures Monitoring Program June 8, 2012 Letters B.1.29.2 /procedure to clarify that the discharge structure,.
2.06.003 Audit Items security diesel generator building, trenches, valve and 238, 320 pits, manholes, duct banks, underground fuel oil tank 2.06.057 foundations, manway seals and gaskets, hatch seals and gaskets, underwater concrete in the intake structure, and crane rails and girders are included in the program. In addition, the Structures Monitoring Program will be revised to requi.re opportunistic inspections of-inaccessible concrete-areas when -they.become: ac-e ib "" ."'..26.,,E' fi Or Monitoring P'roram guidance.or.
June 8," 201.-, Letters, .1 29 2.perormig..strucltu6ral, exam inations .of .elastomers--
... 2 .06.003 LAuditite (seals, gaskets, seismic joint filler; and roof and' 3.. .elastomers) to identify crackifng and change in' 2.06.057._ __ material properties.
_ _"_ _ __"_ _'27 Enhance the Water Control Structures Monitoring June 8, 2012 Letters B.1.29.3 /Program scope to include the east breakwater, jetties, 2.06.003 Audit Item and onshore revetments in addition to the main a[ 30' .breakwater.
j 2.06.057 4 COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 28 Enhance System Walkdown Program guidance June 8, 2012 Letters B.1.30 /documents to perform periodic system engineer 2.06.003 Audit Items inspections of systems in scope and subject to aging and 320, 327 management review for license renewal in 2.06.057 accordance with 10 CFR 54.4(a)(1) and (a)(3).Inspections shall include areas surrounding the subject systems to identify hazards to those systems.Inspections of nearby systems that could impact the subject systems will include SSCs that are in scope and subject to aging management review for license renewal in accordance with 10 CFR 54.4(a)(2).
29 Implement the Thermal Aging and Neutron Irradiation June 8, 2012 Letters B.1.31 /Embrittlement of Cast Austenitic Stainless Steel 2.06.003 Audit Items (CASS) Program as described in LRA Section B.1.31. and 257, 320 2.06.057 30 Perform a code repair of the CRD return line nozzle June 30, 2015 Letter B.1.3 / Audit to cap weld if the installed weld repair is not approved 2.06.057 Items 141, via accepted code cases, revised codes, or an 320 approved r!elief request for subsequent inspection intervals.
-.1 --~C-~ti I I ~ -A3/4 -'-A, {~'3/4V.--' I -I V .-.1 ~5 COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section Nom Comments 31 At least 2 years prior to entering the period of extended operation, for the locations identified in NUREG/CR-6260 for BWRs of the PNPS vintage, PNPS will implement one or more of the following:
(1) Refine the fatigue analyses to determine valid CUFs less than 1 when accounting for the effects of reactor water environment.
This includes applying the appropriate Fen factors to valid CUFs determined in accordance with one of the following:
- 1. For locations, including NUREG/CR-6260 locations, with existing fatigue analysis valid for the period of extended operation, use the existing CUF to determine the environmentally adjusted CUF.2. More limiting PNPS-specific locations with a valid CUF may be added in addition to the NUREGiCR-6260 locations.
- 3. Representative CUF values from other plants, adjusted to or enveloping the PNPS plant specific external loads may be used if demonstrated applicable to PNPS.4. An analysis using an NRC-approved version of the ASME code of NRC-approved alternative (e.g., NRC-approved code case) may be performed-to determine a ,alid-CUF.
The determination of Fen will account for operating times with both hydrogen water chemistry and normal water chemistry.
.(2) Manage the effects of aging due to fatigue at the affected locations by an inspection program that has been reviewed and approbved by the NRC (e.g., periodic non-destructive eka.innt ion of the affected locations at inspection tbobe determined by a method acceptable to the NRC)..'ý(3) Repair or re.place the affected e',xceeding a CUF oft.. -:: Should PNPS select the option to rianhage the aging effects due to environmental-assisted fatigue during the*period of extended operation, details of the aging management program such as scope, qualification, method, and frequency will be submitted to the NRC at least 2 years prior to the period of extended operation.
June 8, 2012 June 8, 2010 for submitting the aging management program if PNPS selects the option of managing the affects of aging due to environmentally assisted fatigue.Letters 2.06.057 and 2.06.064 and 2.06.081 and 2.07.005 4.3.3 / Audit Items 302, 346"d;~J 32 Implement the enhanced Bolting Integrity Program June 8, 2012 Letters Audit items described in Attachment C of Pilgrim License 2.06.057 364, 373, Renewal Application Amendment 5 (Letter 2.06.064).
and 389, 390, 2.06.064 432, 443, and 470 2.06.081 33 PNPS will inspect the inaccessible jet pump thermal As stated in the Letter Audit Items sleeve and core spray thermal sleeve welds if and commitment.
2.06.057 320,488 when the necessary technique and equipment become available and the technique is demonstrated by the vendor, including delivery system.6
- COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 34 Within the first 6 years of the period of extended June 8, 2018 Letter Audit Items operation and every 12 years thereafter, PNPS will 2.06.057 320, 461 inspect the access hole covers with UT methods. and Alternatively, PNPS will inspect the access hole 2.06.089 covers in accordance with BWRVIP guidelines should such guidance become available.
35 At least 2 years prior to entering the period of June 8, 2012 Letters Audit Item extended operation, for reactor vessel components, June 8, 2010 for 2.06.057 345 including the feedwater nozzles, PNPS will implement submitting the and one or more of the following:
aging 2.06.064 (1) Refine the fatigue analyses to determine valid management and CUFs less than 1. Determine valid CUFs based on program if PNPS 2.06.081 numbers of transient cycles projected to be valid selects the for the period of extended operation.
Determine option of CUFs in accordance with an NRC-approved managing the version of the ASME code or NRC-approved ae aging.alternative (e.g., NRC-approved code case). affects of aging.(2) Manage the effects of aging due~to fatigue at the affected locations by an inspection program that has been-reviewedý andapproved by the NRC (e.g., periodic non-destructive examination of the affected locations at inspection intervals to be determined by a method acceptable to the NRC).(3) Repair of replace the affected locations before exceeding a CUF of 1.0.Should PNPS select the. ppti.no to manage the agingý .i:,.effects dueto fatiguel during, the period of extehded'.
" operation, detail.s.of the agingi managegment program ,-and frequency:
.."willbe: subm ittedetoathe"NRC ateast'2 years prior to- -thepro of extended.
opberation.'_______
36 To ensure that significant degradation on'the bottom June 8, 2012 Letter Auditfltems of the condensate storage tank is not occurring, a 2.06.057 320, 363 one-time ultrasonic thickness examination in accessible areas of the bottom of the condensate storage tank will be performed.
Standard examination and sampling techniques will be utilized.37 The BWR Vessel Internals Program includes June 8, 2012 Letter A.2.1.8/inspections of the steam dryer. Inspections of the 2.06.089 Conference steam dryer will follow the guidelines of BWRVIP-1 39 call on and General Electric SIL 644 Rev. 1. September 25, 2006 1 COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 38 Enhance the Diesel Fuel Monitoring Program to June 8, 2012 Letter B.1.10 /include periodic ultrasonic thickness measurement of 2.06.089 Audit Item the bottom surface of the diesel fire pump day tank. 565 The first ultrasonic inspection of the bottom surface of the diesel fire pump day tank will occur prior to the period of extended operation, following engineering analysis to determine acceptance criteria and test locations.
Subsequent test intervals will be determined based on the first inspection results.39 Perform a one-time inspection of the Main Stack June 8, 2012 Letter B.1.23/foundation'prior to the period of extended operation.
2.06.094 Audit Item 581 40 Enhance the Oil Analysis Program by documenting June 8, 2012 Letter B.1.22 /program elements 1 through 7 in controlled 2.06.094 Audit Items documents.
The program elements will include 553 and 589 enhancements identified in the PNPS license renewal application and subsequent amendments to the application.
The program will include periodic sampling for the parameters specified under the Parameters Monitored/Inspected attribute of NUREG-1 801 Section XI.M39, Lubricating Oil Analysis.
The controlled documents will specify appropriate acceptance criteria and corrective actions in,the event acceptance criteria are not met. The:6asis for acceptance criteria will be defined. _-___________,____-_
4 g1,' Enhance the Containment Inservice Inspection. (CI) Jne8, 2012- Letter, 17 and'"Program to require augmented in6pection., 2 06.094< B 6.1:iaccordance with.ASME SedtibnXI .IWE-1`.240Oof-he-;drywell shell adjacent to th 'sand cushlio'n.IoiL 7.1.'. -,__ indrications of water- leakage into'theannulus air gap. _' '__, , _ _ _ :-42 Implement the Bolted Cable Connections Program, June 8, 2012 Letter A.2.1.40 and described in Attachment C of Pilgrim License 2.07.003 B.1.34 Renewal Application 11 (Letter 2.07.003), prior to the period of extended operation.
43 Include within the Structures Monitoring Program June 8, 2012 Letter A.2.1.32 and provisions to ensure groundwater samples are 2.07.005 B.1.29.2 evaluated periodically to assess the aggressiveness of groundwater to concrete, as described in Attachment E of License Renewal Application 12 (Letter 2.07.005), prior to the period of extended operation.
44 Perform another set of the UT measurements just As stated in the Letter A.2.1.17 and above and adjacent to the sand cushion region prior commitment.
2.07.010 B. 1.16.1 to the period of extended operation and once within the first 10 years of the period of extended operation.
1 8
- COMMITMENT IMPLEMENTATION SOURCE Related SCHEDULE LRA Section No./Comments 45 If groundwater continues to collect on the Torus June 8, 2012 Letter A.2.1.32 and Room floor, obtain samples and test such water to 2.07.010 B.1.29.2 determine its pH and verify the water is non-aggressive as defined in NUREG-1 801 Section Ill.A1 item II1.A.1-4 once prior to the period of extended operation.
A~ -, 9 ATTACHMENT B to Letter 2.07.010 (9 pages)Clarifying Drywell Shell Information Superseding the Information Provided in LRA Amendment 1 and LRA Amendment 2"'F--I Pilgrim Nuclear Power Station Drywell Shell Information Purpose For license renewal, the NRC evaluates the potential for corrosion of the Mark I steel containment drywell shell. This issue previously was the subject of generic NRC communications in the 1980s. Specifically, Generic Letter (GL) 87-05 addressed potential degradation of Mark I drywells due to corrosion.
The following provides additional information on the Pilgrim Station drywell shell relative to recent industry experience in this area.Background In 1980, the Oyster Creek Station observed water coming from lines that drain water from the annulus region between the drywell wall and the surrounding concrete and the sand cushion region. The water source was initially identified in 1983 as coming from the Drywell-Refueling Cavity bellows drain line gasket. After performing ultrasonic thickness measurements in 1986, Oyster Creek Station reported that corrosion and material loss had occurred to the Drywell Shell in the area of the sand-cushion.
This finding led to the issuance of NRC Information Notice 86-99, "Degradation of Steel Containments," Generic Letter 87-05, "Request for Additional Information
-Assessment of Licensee Measures to Mitigate and/or Identify Potential Degradation of Mark I Drywells," and Information Notice 86-99 Supplement 1.The purpose of GL 87-05 was "...to initiate the collection of information of the lice nsee's current and proposed action to assure the degradation of the Drywell Shell plates adjacent to the sand-cushion has not occurred and to determine if augmented inspections above and beyond those planned by the licensee's are necessary." In 1995,;subsequent to the GL responses, the staff approved the use of ASME Section X.i-X-;.-,e IWE (Requirements for Class MC and Metallic Liners of Class CC Componentsuq.
of Light-ater Cooled Plants) which exempts,;
in accordance
'with'Subparagraph IWE-.1220(b), "embedded or inaccessible portions of containment vessels; parts, and .'- ,'appurtenances that met the requirements of the original Construction Code..." However, Paragiraph IWE-1 240 estaiishes criteria for determininthe heed foraugmented:
examinations.
PNPS Primary Containment Design PNPS employs a low-leakage pressure suppression system which houses the reactor vessel, the reactor coolant recirculation loops, and other branch connections of the reactor primary system. The pressure suppression system consists of a drvwell, a pressure suppression chamber containing a large volume of water, a connecting vent system between the drywell and the pressure suppression chamber, isolation valves, vacuum relief system, containment cooling systems, and other service equipment.
The drywell is a light bulb-shaped carbon steel primary containment structure with a spherical lower portion, 64 feet in diameter, and a cylindrical upper portion 34 feet 2 inches in diameter.
The overall height is approximately 110 feet. The drywell is enclosed in reinforced concrete for shielding purposes and to provide additional resistance to deformation and buckling in areas where the concrete backs up the steel shell. Shielding above the drywell is provided by removable, segmented, reinforced concrete shield plugs 1 Pilgrim Nuclear Power Station Drywell Shell Information located on the reactor building refuel floor. The reinforced concrete drywell floor contains the drywell floor drain and equipment drain sumps and supports the reactor pedestal.The design, fabrication, inspection, and testing of the drywell complies with requirements of the ASME Boiler & Pressure Vessel Code,Section III, Subsection B, Requirements for Class B Vessels, which pertain to containment vessels for nuclear power stations.Drywell Shell Exterior The sand cushion at the base of the drywell is designed to provide a smooth transition to reduce thermal and mechanical discontinuities.
The sand provides lateral support to the drywell in this region. The sand cushion area is drained to protect the exterior surface of the drywell shell at the sand cushion interface from water that might enter the air gap.The coating specified for the PNPS drywell shell exterior surfaces was an alkyd-base primer (red lead or zinc chromate).
No degradation of this coating in the sand cushion area was noted in 1987 when fiberscopes were used to examine the 4 inch annulus air gap drain lines.To ensure the drywell shell exterior remains dry during refueling evolutions, the drywell to reactor building bellows assembly separates the refueling cavity filled with water from the exterior surface of the drywell shell. Any leakage through the bellows assembly is directed to a drain system (refueling bellows seal trough drains) which is equipped with an aladrm for notification of operators.
The drywell exterior surface is essentially inaccessible for inspection.
Surfaces that are accessible for examination include the drywell hemispherical head exterior surfaces and some penetrations in the structure.
Di ..wel 11 -Shell nter 'ior, t .-'Thelmajority of the upper .portion of the drywell shellinterio surfaces,,are a-inspecti6nexcept the lower, portion .,of the drywell where, itis covered by the 6oncretei.I--
-drywell floor which provides structural support for the reactor pedestal and other.ý equipment...
-, The PNPS primary containment system is inerted with nitrogen gas during normal power-,: operations so that oxygen levels are maintained at less than 4%. Inerting with nitrogen provides an atmosphere that is not conducive to corrosion of containment interior surfaces.Operating Experience and Actions Taken to Prevent Dryw.el! Corrosion There has been no observed leakage causing moisture in the vicinity of the sand cushion at PNPS and no moisture has been detected or is suspected on the inaccessible areas of the drywell shell. Further, as discussed above, any potential leakage through the refueling bellows assembly is directed to a drain system. Therefore, no additional components have been identified that require aging management review as a source of moisture that might affect the drywell shell in the lower region.As stated in the response to GL 87-05, PNPS performed UT thickness measurements of the drywell shell in January 1987. The UT thickness measurements were taken at twelve 2 Pilgrim Nuclear Power Station Drywell Shell Information locations directly above the sand cushion region. These measurements detected no loss of wall thickness.
PNPS verified that the annulus air gap drain lines are unobstructed.
In 1987, access holes were machined in the drain line elbows on all four drain lines to allow access for remote visual examination using fiberscopes.
This inspection determined that the four annulus air gap drains are unobstructed and found no signs of corrosion on visible portions of the drywell surface.PNPS monitors the annulus air gap drains during every refueling outage.PNPS performed four additional UT thickness measurements adjacent to the sand cushion region at the 9 foot 1 inch elevation.
Three (3) of the measurements were performed in 1999 and one (1) in 2001. The sand cushion region of the drywell shell is inaccessible unless concrete is removed. For the examinations in 1999 and 2001, concrete at the periphery of the 9 foot 2 inch elevation was chipped away to allow UT wall thickness measurements of the drywell shell to be taken at the level of the upper sand cushion. These examinations are destructive in nature and are performed in a high radiation area. The areas were then re-grouted prior to resuming operations.
The observed wall thickness readings showed the drywell wall thickness in these areas to be essentially as-built.
Based on the following four factors, PNPS removed UT thickness measurements in the sand cushion region from the IWE program after the 2001 outage: Satisfactory results from monitoring for leakage from the annulus air gap drains.* Satisfactory drywell wall thickness at the 9 foot 1 inch elevation sand cushion region (and "ipper drywell) after 27 years of. operation (as of 1999)., High fadiation exists in areas of sand cushion UT exams."*" -The4 potential for damage to tbedrywellshell from concrete removaltools used tot facihtatethe examina'ions.:
-Lic !ense renewal commitment:4 has b'ehni ade toprovide added assUrance thatthe actions to prevent water intrusion into the annulus air gap and sand cushion region have been successful in mitigating the potential for corrosion.
License renewal, commitment 44 is to perform another set of the UT measurements at the previous measurement locations just above and adjacent to the sand cushion region prior to the period of extended operation and once within the first 10 years of the period of extended operation.
License renewal commitment 41 addresses actions to take if indications of water leakage into the annulus air gap are identified.
3 Pilgrim Nuclear Power Station Drywell Shell Information Ongoing Actions to Prevent Drywell Corrosion The following ongoing actions are being taken to prevent and identify drywell corrosion: " PNPS monitors the four annulus air gap drains twice every refuel outage, once after floodup and again prior to flooddown at the end of the outage. Leakage has never been detected from the annulus air gap drains at PNPS." Functional checks are performed prior to each refueling outage on the flow switch associated with the bellows seal leakage monitoringi system." Drywell interior surfaces are examined for degradation every refueling outage as required by Technical Specification 4.7.A.2.d.
Additionally, drywell interior surfaces are examined every other outage in accordance with the PNPS IWE Program.Drywell structures are examined in accordance with ASME Section XI -1998 Edition with 2000 Addenda, Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Plants. Since IWE requirements were mandated in 1996, no areas have been identified that exceeded code acceptance criteria on the drywell interior surfaces during these inspections.
- PNPS inspects the liner drains for the water reservoirs on the refuel floor (e.g., spent fuel pool, dryer/separator pool, and reactor cavity) for leakage. Leakage into the liner drains could be a precursor for water leaks which could wet the drywell shell exterior surface. These drains are examined for leakage after filling the refueling cavity.* ParagraphIWE.1242 of the ASME XI that surface areas likely to.... .expeie accelerated degradation and aging require augmented examination.:;.
ese;,,xamina in thePNPSs 1.Program.along:with:other
ý Y,..k,, , coiitainm~ent exea-ina'tions'.
The tW eu~rneisf
,:..., ..:,...... .c ntin entex mm bon .heIW E requireme'nts for augmented .examinat 0 are:,:,,.):, -. requ ired b 10 F 50.55a "'The coderequires:
owne6rs to identify locations they believe are suspect or potential problem areas for'augmented inspection.
After a review of PNPS drywell construction methods, PNPS identified various locations for augmented examination.
Construction procedures required the gap forming material (Ethafoam) to be removed after each concrete lift had hardened and narrow polyurethane foam sealing strips to be inserted and left in place at the top of each lift, to prevent foreign material from entering the air gap as work progressed.
There is some potential that these sealing strips might trap and hold leakage from the bellows and fuel pool, resulting in corrosion of the drywell shell outer surface. For this reason, augmented UT examinations in the upper drywell at elevation 72 feet (two locations) and elevation 83 feet (four locations) were performed in vertical strips to ensure the region of interest was examined.
Three (3) of the examinations were performed in 1999 and three (3) in 2001. These examinations revealed no degradation of the drywell shell thickness in the upper drywell.4 Pilgrim Nuclear Power Station Drywell Shell Information UT thickness examinations will continue to be performed under the PNPS IWE program at two locations in the upper drywell immediately adjacent to the fuel pool due to the potential for leakage from the fuel pool liner.The drywell shell to floor joint is inspected under the PNPS IWE Program.To provide added assurance that the actions to prevent water intrusion into the annulus air gap and sand cushion region have been successful and thereby, mitigating the potential for corrosion license renewal commitment 44 is to perform another set of the UT measurements at the previous measurement locations just above and adjacent to the sand cushion region prior to the period of extended operation and once within the first 10 years of the period of extended operation.
License renewal commitment 41 addresses actions to take if indications of water leakage into the annulus air gap are identified.
Conclusion PNPS has effectively addressed the issue of drywell shell corrosion through actions taken in response to GL 87-05 as well as additional actions subsequent to the response to GL 87-05.UT examinations to determine the drywell wall thickness at the sand cushion region and upper drywell indicated no detectable loss of material and hence no discernable corrosion.
rate.Based on this corrosion rate, no discernable loss of drywell shell thickness is projected through the period of extended operation.
The above described ongoing actions to prevent drywell shell degradation provide continuing reasonable assurance of satisfactory drywell shell condition through the period of extended operation.
- 1-3/4'R 5 L..~ ~H_A2 6 Taken. from IIWA~DO1 S D5PECflQN POINT NUTJBOR 0 AINNULUS AMR GAP ORAN, LMNS.VETHAEQO POINTS (8 PLACESýU3 UPPER ORlWU. (E Tt-Or & BS-U) SHELL THTIGIESS~
O lOV*R DWYWEU. (E. 9'-0-) 94IELL TH16KNESS.
0 TORUTS RfiH THICKNESS AT WEAN WATER LINE El. (-) ' (FROMI 0.0.)OTORUS SHELL THICKNESNSS AT EL (-) ll-6! (rROU OT.(6 REMOVABLE SHIELDING WALL H-J ChRw 7 j IrLOOR OFTOIZU AIR GAP SNP POCKET iDETAIL, SAND POCKET ,T.A"KEN FROM PNPS DWG- C 1iti<::
9 ATTACHMENT C to Letter 2.07.010 (1 page)Changes to the LRA The following changes to the LRA stem from the conference call on January 23, 2007 with the NRC license renewal staff.LRA Section A.2.1.17 Inservice Inspection
-Containment Inservice Inspection (CII) Program, is revised by adding the following (boldface wording added): License renewal commitment 44 specifies the performance of another set of UT measurements just above and adjacent to the sand cushion region prior to the period of extended operation and once within the first 10 years of the period of extended operation.
LRA Section A.2.1.32 Structures Monitoring
-Structures Monitoring Program, is revised by adding the following (boldface wording added): If groundwater continues to collect on the Torus Room floor, obtain samples and test such water to determine its pH and verify the water is non-aggressive as defined in NUREG-1800 Section IIl.A1 item IIl.A.1-4.
License renewal commitment 45 specifies testing of water on the Torus Room floor if groundwater continues to collect on the floor once prior to the period of extended operation.