noc-ae-14003149 u. s. nuclear regulatory commission ... · the following provides the...

Nuclear Operating Company

South Texas Proped Electric Generating Station PO. Bo 289 Wdsaorth, Teuas 77483 AA

June 26, 2014NOC-AE-1400314910 CFR 54File: G25

U. S. Nuclear Regulatory CommissionAttention: Document Control DeskWashington, DC 20555-0001

South Texas ProjectUnits 1 and 2

Docket Nos. STN 50-498, STN 50-499Review of Final License Renewal Interim Staff Guidance LR-ISG-2011-03 "Changes to theGeneric Aging Lessons Learned (GALL) Report Revision 2 Aging Management Program

XI.M41, "Buried and Underground Piping and Tanks" and update toLicense Renewal Application (TAC Nos. ME4936 and ME4937)

m

References: 1. Letter from G. T. Powell, STPNOC, to NRC Document Control Desk, "LicenseRenewal Application", dated October 25, 2010 (NOC-AE-1 0002607)(ML103010257)

2. Final License Renewal Interim Staff Guidance LR-ISG-2011-03 "Changes to theGeneric Aging Lessons Learned (GALL) Report Revision 2 Aging ManagementProgram XI.M41, "Buried and Underground Piping and Tanks" (ML12138A296)

3. Letter from G.T. Powell, STPNOC, to NRC Document Control Desk, Response toRequest for Additional Information for the Review of the South Texas Project,Units 1 and 2, License Renewal Application - Set 27 dated June 3, 2014(NOC-AE-14003141)

By Reference 1, STP Nuclear Operating Company (STPNOC) submitted a License RenewalApplication (LRA) for South Texas Project (STP) Units 1 and 2. By Reference 2, the NRC staffprovides additional guidance for review of the STP LRA Aging Management Program XI.M41.STPNOC's review and changes to LRA Aging Management Program XI.M41 is depicted as line-in/line-out pages provided in Enclosure 1.

This correspondence provides supplemental information regarding the review of ISG 2011-03,pertaining to "Buried and Underground Piping and Tanks" inadvertently omitted in Reference 3.The NRC license renewal staff was notified per telecom on 6/11/2014 of the discrepancy.

Enclosure 2 includes revised regulatory commitment Item #13 depicted as line-in/line-out pagesto Table A4-1 of the LRA. There are no other regulatory commitments in this letter.

STI: 33889306

NOC-AE-14003149 of 3

Should you have any questions regarding this letter, please contact either Arden Aldridge, STPLicense Renewal Project Lead, at (361) 972-8243 or Rafael Gonzales, STP License RenewalProject regulatory point-of-contact, at (361) 972-4779.

I declare under penalty of perjury that the foregoing is true and correct.

Executed onDate

G.T. PowellSite Vice President

RJG

Enclosures: 1. STPNOC Response to LR-ISG-2011-03 and LRA Changes with Line-in/Line-out Annotations

2. STPNOC Regulatory Commitments

NOC-AE-14003149 of 3

cc:(paper copy)

(electronic copy)

Regional Administrator, Region IVU. S. Nuclear Regulatory Commission1600 East Lamar BoulevardArlington, Texas 76011-4511

Balwant K. SingalSenior Project ManagerU.S. Nuclear Regulatory CommissionOne White Flint North (MS 8B1)11555 Rockville PikeRockville, MD 20852

Senior Resident InspectorU. S. Nuclear Regulatory CommissionP. O. Box 289, Mail Code: MN116Wadsworth, TX 77483

John W. DailyLicense Renewal Project Manager (Safety)U.S. Nuclear Regulatory CommissionOne White Flint North (MS 011-Fl)Washington, DC 20555-0001

Tam TranLicense Renewal Project Manager(Environmental)U. S. Nuclear Regulatory CommissionOne White Flint North (MS 011 F01)Washington, DC 20555-0001

A. H. Gutterman, EsquireKathryn M. Sutton, EsquireMorgan, Lewis & Bockius, LLP

John RaganChris O'HaraJim von SuskilNRG South Texas LP

Kevin PolioCris EugsterL.D. BlaylockCPS Energy

Peter NemethCrain Caton & James, P.C.

C. MeleJohn WesterCity of Austin

Robert FreeTexas Department of State Health Services

Richard A. RatliffTexas Department of State Health Services

Balwant K. SingalJohn W. DailyTam TranU. S. Nuclear Regulatory Commission

Enclosure 1NOC-AE-14003149

Enclosure 1

STPNOC Response to LR-ISG-2011-03 and LRA Changes withLine-in/Line-out Annotations

Enclosure 1NOC-AE-14003149Page 1 of 12

Guidance from LR-ISG-2011-03

INTRODUCTION

This final license renewal interim staff guidance (LR-ISG) LR-ISG-2011-03, "Changes to theGeneric Aging Lessons Learned (GALL) Report Revision 2 Aging Management Program(AMP)XI.M41, 'Buried and Underground Piping and Tanks'," provides changes to GALL ReportAMP XI.M41 as described below. The AMP, as modified herein, provides one acceptableapproach for managing the effects of aging of buried and underground piping and tanks withinthe scope of the License Renewal Rule (Title 10 of the Code of Federal Regulations, Part 54,"Requirements for Renewal of Operating Licenses for Nuclear Power Plants" (10 CFR Part54)).

This LR-ISG also changes Table 3.0-1, "FSAR Supplement for Aging -Management ofApplicable Systems," in the Standard Review Plan for Review of License Renewal Applicationsfor Nuclear Power Plants (SRP-LR). A licensee may reference this ISG in its license renewalapplication (LRA) to demonstrate that its buried underground piping and tanks program isacceptable to the staff until the guidance in this LR-ISG is implemented into the next update ofthe license renewal guidance documents.

STPNOC Response:

The following provides the line-in/line-out details on how STP is applying the updated guidanceof LR-ISG-2011-03 into the "License Renewal Application aging management program" (AMPXI.M41).


A1.18 Buried Piping and Tanks Inspection

The Buried Piping and Tanks Inspection program manages the loss of material on externalsurfaces of buried and underground limit8d acce components. Preventive and mitigativemeasures, including verification of coatings quality, backfill requirements, and cathodicprotection, are employed to manage aging of buried components. Underground componentshave been are protectively coated where required.

The cathodic protection system is operated consistent with the guidance of NACE SP01 69-2007 for piping and is monitored to ensure that protection is being provided. The cathodicprotection system is operational (available) at least 85 percent of the time and provideseffective protection for buried piping as evidenced by meeting the acceptance criteria at least80 percent of the time since either 10 years prior to the period of extended operation or sinceinstallation or refurbishment. An annual cathodic protection survey is performed consistentwith NACE SP0169-2007.

Opportunistic and directed visual inspections will monitor the condition of external surfaces,protective coatings and wrappings found on steel, stainless steel and copper alloy components.Any evidence of damaged wrapping or coating defects will be an indicator of possible corrosiondamage to the external surface of the components.

Hydrostatic tests of 25 percent of the subiect piping will be performed on an interval not toexceed 5 years, or an internal inspection of 25 percent of the subiect piping by a methodcapable of accurately determining pipe wall thickness every 10 years may be performed as analternate to directed inspections. Flow testing of the fire mains as described inSection 7.3 ofNFPA 25, 2011 Edition is credited in lieu of visual inspections.


B2.1.18 Buried Piping and Tanks Inspection

Program Description

The Buried Piping and Tanks Inspection program manages the loss of material on externalsurfaces of buried and underground limited accesG components.

The Buried Piping and Tanks Inspection program includes inspections or flow testinq of buriedsteel, stainless steel, copper alloy piping, underground steel, stainless steel piping within theAuxiliary Feedwater System, the Lighting Diesel Generator System, the Essential CoolingWater (ECW) and ECW Screen Wash System, the Fire Protection System, and the Oily WasteSystem (OW).

Preventive and mitigative actions are taken to ensure the pipinge is coated, backfilled andcathodically protected. The buried steel and copper alloy piping managed by this program iscathodically protected, and the cathodic protection system is monitored to ensure it is providiRgprot9ctiGR. The cathodic protection system is designed in accordance with NACE RP-01-691972. The performance of the cathodic protection system is consistent with the guidelines ofNACE SP0169-2007. An annual survey ensures that the pipe-to-soil potential is acceptable.

Cathodic protection is operational (available) at least 85 percent of the time from either 10years prior to the period of extended operation or from installation or refurbishment, whicheveris shorter. Cathodic protection is effective protection for buried piping as evidenced by meetingthe acceptance criteria at least 80 percent of the time since either 10 years prior to the periodof extended operation or since installation or refurbishment, whichever is shorter.

Opportunistic and directed visual inspections monitor the condition of the external surfaces,backfill, protective coatings and wrappings of steel, stainless steeland copper alloy buried and,,de,....GI-components. Inspection locations are selected based on susceptibility todegradation and consequences of failure. A minimum of 10 feet of pipe of each material typeis inspected. The inspections consist of a 100 percent visual inspection of the exposed pipe.

Category C inspections are used when the external cathodic protection system for buried steelor copper alloy pipe meets the acceptance criteria. Category C inspections are 0.5 percentNot-to-Exceed (NTE) two inspections of that piping per inspection period.

Category E inspections are used when the cathodic protection system has been installed butportions of the piping covered by that system fail to meet the acceptance criteria. Category Einspections are 5 percent, NTE 10 inspections, in years 30 to 40: 6 percent, NTE 15inspections, in years 40 to 50: and 7.5 percent, NTE 18 inspections, in years 50 to 60.

The Auxiliary Feedwater system has stainless steel pipe underground in a vault outside of theAuxiliary Feedwater Storage tank. This stainless steel pipe will undergo two directed visualinspections each 10-year inspection period.

The OW system has steel pipe under-ground in sumps located in the yard. This undergroundpipe will undergo 2% NTE 4 directed visual inspection each 10-year inspection period.


In lieu of visual inspections of the fire protection system, STP credits flow testing of the firemains as described in Section 7.3 of NFPA 25, 2011 Edition.

Inspections will begqin during the 10-year period prior to entering the period of extendedoperation. Upon entering the period of extended operation, inspections will occur every 10years.

Visual inspections of metallic components are supplemented with surface or volumetricnondestructive testing (NDT) if significant indications are observed to determine local area wallthickness. If adverse indications are detected, inspection sample sizes within the affectedpiping categories are doubled. If adverse indications are found in the expanded sample,further increases in inspection sample size is based on an analysis of extent of cause andextent of condition.

Hydrostatic test of 25 percent of the subiect piping on an interval is not to exceed 5 years, orinternal inspection of 25 percent of the subiect piping by a method capable of accuratelydetermining pipe wall thickness every 10 years may be performed as an alternate to directedinspections.

There are no components fabricated with polymeric, cementitious, or concrete materials withinthe scope of license renewal that credit this program for aging management. There are noburied or underground tanks within the scope of license renewal.

Any evidence of aging effects, such as loss of material, racki~ng or changes in materialproperties, requires initiation of corrective actions.The c~athodic protection system; is sureyed annually to ensure that it is 6upplying adoquato.protection to buried piping•,,The program includes visual iunspection of etn surface' . .pplemented by sur.face and/ovmIc ,,-,-non destr•c.tive testing of the inte•al or extera•l surfafce during opportunistic oplanned inspections. Hydrotesting m~ay be porfo~rm~ed in liou of directod inspections.Aging management of the internal surfaces of buried and underground piping is accomplishedthrough the use of the Open-Cycle Cooling Water System program (B2.1.9), Closed-CycleCooling Water System program (B2.1.10), Inspection of Internal Surfaces in MiscellaneousPiping and Ducting Components program (B2.1.22), Fuel Oil Chemistry program (B2.1.14),Fire Water System program (B2.1.13) and Water Chemistry program (B2.1.2). Selectiveleaching of buried or underground components is managed by the Selective Leaching ofMaterials program (B2.1.17) or the Selective Leaching of Aluminum Bronze program (B2.1.37).

NUREG-1801 Consistency

The Buried Piping and Tanks Inspection program is an existing program that, followingenhancement, will be consistent with exception to NUREG-1801, Section XI.M41, Buried andUnderground Piping and Tanks.

Exceptions to NUREG-1801

Program Elements Affected:

Preventive Actions (Element 2)


Section XI.M41 Table 2a of NUREG-1801 Revision 2, requires the backfill to be consistent withNACE SP0169 Section 5.2.3.

NACE SP0169 Section 5.2.3.5 states that pipe should be lowered carefully into the ditch toavoid external coating damage. The original installation specification does not include thispractice. However the subgrade of the trench was prepared by removing all debris andunsuitable material, and the subgrade consists of fine clay and sand that makes up the naturalsoil or backfill.

The backfill used is consistent with the ASTM D 448-08 size 67 standard. The subgradepreparation, and small grain size backfill used in the original installation, which provide softbedding for piping set into the trench, are not expected to have damaged the coating of thepiping. Plant procedures will be enhanced to ensure that the piping is lowered carefully into atrench to avoid damage to the external coatings.

Section XI.M41 Table 2a of NUREG-1801 Revision 2, requires that backfill be consistent withNACE SP0169 Section 5.2.3. NACE SP0169 Section 5.2.3.6 states that care should be takenduring backfilling so that rocks and debris do not strike and damage the pipe coating. Theoriginal installation specification for backfilling piping does not include this practice, with theexception of the ECW piping. However a fine grain size backfill was used that met the ASTM D448-08 size 67 standard. The use of this backfill during backfilling is not expected to damagethe pipe coating. Plant procedures will be enhanced so that, during backfill repair orreplacement, care is taken to avoid damage to pipe coatings while backfilling the trench.

Section XI.M41 Table 2a of NUREG-1801 Revision 2, requires coating of pipe in accordancewith NACE SP0169-2007, Table 1. Table 1 recommends that coal tar coatings are inaccordance with AWWA C-203, and that prefabricated films are in accordance with AWWA C-214 or C-209. These standards were not referenced in STP installation specifications.However, the coatings were applied in accordance with plant-defined specifications. Plantspecifications are consistent with the intent of the AWWA coating standards called out in NACESP0169-2007. Installation specifications ensure that any defects in the coatings were repairedprior to backfilling over the pipe.

Enhancements

Prior to the period of extended operation, the following enhancements will be implemented inthe following program elements:

Preventive Actions (Element 2)

Plant specifications will be enhanced to include the following:

* Indicate that pipe should be lowered carefully into the ditch to avoid external coatingdamage.

* Proper storage and handling must be used to prevent damage to pipe coating prior toinstallation. These practices include padded storage, use of proper slings forinstallation and ultraviolet light-resistant topcoats.

Over-excavate trenches and use qualified backfill for bedding piping. Take care duringbackfilling to prevent rocks and debris from striking and damaging the pipe coating.


Include the coating used for copper alloy buried piping in the coating database. Thecoating system must be in accordance with NACE SP0169-2007, Table 1, and will beused for repair or for new coatings of the buried copper alloy piping in the essentialcooling water system.

Indicate that the portion of the essential cooling water system copper alloy pipingdirectly embedded in backfill or directly encased in concrete must be coated, extendingthe coating 2 feet or more above grade.

Plant procedures will be enhanced to include the following:

Backfill that is located within 6 inches of the pipe that is consistent with ASTM D 448-08size number 67 is considered acceptable. Backfill quality is determined throughexamination during the inspections conducted by this program. Backfill that does notmeet the ASTM criteria during the initial and subsequent inspections of this program isconsidered acceptable if the inspections of buried piping do not reveal evidence ofmechanical damage to the pipe coatings due to the backfill.

The cathodic protection system engineer is responsible for ensuring the cathodicprotection system survey is performed annually, and the rectifier current is checked andrecorded every 2 months.

Monitor cathodic protection system rectifier output every 2 months. The measuredcurrent at each rectifier is recorded and compared against a target value. Followingcompletion of the plant yard cathodic protection system annual survey, record thecurrent of the rectifier used to achieve an acceptable pipe/soil potential. That currentwill be the target current for the rectifier. If the current measured at the rectifier duringthe bimonthly monitoring deviates significantly from the target value, a condition reportshould be created. The rectifier current should be adjusted to an acceptable value.The results of the survey will be documented and trended to identify degradingconditions. When degraded rectifier performance is identified, corrective actions arerequired to be initiated. The system should not be operated outside of establishedacceptable limits for longer than 90 days.

During the plant yard cathodic protection system annual survey, evaluate theeffectiveness of isolating fittings, continuity bonds and casing isolation. This may beaccomplished through electrical measurements (NACE SP0169-2007, Section 10.4.4).

The P,6rformanc tAo"•chGnicnr personnel performinq the plant yard cathodicprotection system annual survey must be NACE-certified, certified by a site-approvedtraining procedure consistent with the NACE requirements, or supervised by a NACE-certified inspector.

Parameters Monitored/Inspected (Element 3) and Detection of Aging Effects (Element 4)

Plant procedures will be enhanced to indicate that piping in this program is inspectedusing visual inspections and, if significant indications of degradation are observed, thevisual inspections are supplemented by surface and/or volumetric non-destructivetesting.


Detection of Aging Effects (Element 4)


0 The inspections of this program are conducted every 10 years, beginning in the 10 yearinterval prior to the beginning of the period of extended operation.

0 Buried and underground piping inspection locations are to be selected based on risk,considering susceptibility to degradation and consequences of failure.

0 The risk ranking for buried piping should consider characteristics such as coating type,coating condition, cathodic protection effiGaey efficiency, backfill characteristics, soilresistivity, pipe contents, and pipe function.

0 The risk ranking for underground piping should consider characteristics such as coatingtype, coating condition, exact external environment, pipe contents, pipe function, andflow characteristics within the pipe.

0 The risk ranking should generally give piping systems that are backfilled usingcompacted aggregate a higher inspection priority than comparable systems that arecompletely backfilled using controlled low strength material.

External Corrosion Direct Assessment, as described in NACE Standard PracticeSP0502-2010, is recommended for use in identifying inspection locations. It has beendemonstrated to be an effective method for identification of pipe locations that meritfurther inspection.

Opportunistic examinations of non-leaking pipes may be credited toward the requiredexaminations, if they meet the risk-ranking selection criteria.

Guided wave ultrasonic techniques or other advanced inspection techniques should beused, if practical, for determining piping locations that should be inspected. However,these inspections may not be used as substitutes for inspections required by thisprogram.

An inspection of piping shared between Units 1 and 2 may eiy-be credited toward therequired inspections-ef-ene-RWi . Inspection quantities are increased by 50 percent asSTP has two units.

Any piping, valves, or closure bolting exposed during inspections should be examined.Examine bolting for loss of material and loose or missing fasteners.

There are two alternatives to directed inspections of the buried or underground pipingthat is safoty relatod, hazmat or bothwithin the scope of license renewal. The firstalternative is a hydrostatic test of 25 percent of the subject piping to 110 percent of thedesign pressure of any component within the boundary with test pressure being held foreight hours n aGccordanco with 49 CFR 195 subpa•t E on an interval not to exceed 5years. The second is an internal inspection of 25 percent of the subject piping by amethod capable of accurately determining pipe wall thickness. The inspection mustalso include methods capable of detecting both general and pitting corrosion, and mustbe qualified by the plant, and approved by the NRC.


UT examinations can be considered approved by the NRC. Guided wave inspectiondoes not currently satisfy these inspection technique requirements. Internal inspectionsare to be conducted every 10 years beginning 10 years prior to the period of extendedoperation.lf this inspection iporormed,4 considerationm should be given to NACESP0169 2007 Sections 6.1.2 and 6.3.3.

In lieu of visual inspection of the fire protection system, this program relies on flowtesting of the fire mains as described in Section 7.3 of NFPA 25, 2011 Edition to detectdegradation of the buried pipe.

Define "haz-mat pipe" as pipe that, dluig nRarl peratioR, cort-ntais fluids; that ireleased, would be- derientlt the environmet. This inclu,6des chem~ical suibstances6such as diesel fuel and radi-o..i-.otpeG. TO 1be conSidered hazmat, the concentration o.radioisotopes within the Pipe durFing normnal operation m;ust exceed establishedstandadrds suc-h as the EMPA drinking water standard. In the a-bsen-e of suhstaand-ardsE,the concentra-tion- of the radioisotope mus1t exceed the greater of backgroun~d or reliablelevel of detoctetion. For tritium, the E=PA drinking water standard of (20,000 pCi!L) i

* Each inspection will examine either the entire length of a run of pipe, or a minimum of10 feet. If the entire run of pipe of that material type is less than 10 feet in total length,then the entire run of pipe should be inspected. The inspection consists of a 100percent visual inspection of the exposed pipe.

* Category C inspections are used when the external cathodic Protection system forburied steel or copper alloy pipe meets the acceptance criteria. Category C inspectionsare 0.5 percent Not-to-Exceed (NTE) two inspections of that piping per inspectionperiod are performed.

* Category E inspections are used when the cathodic Protection system has beeninstalled but the portions of the piping covered by that system fail to meet theacceptance criteria. Category E inspections are 5 percent, NTE 10 inspections, inyears 30 to 40: 6 percent, NTE 15 inspections, in years 40 to 50: and 7.5 percent, NTE18 inspections, in years 50 to 60. The following condition must be present.

a) Coatings and backfill are provided in accordance with STP backfillspecification.

b) There have been no leaks in buried piping due to external corrosion andno significant coating degradation or metal loss in more than 10 percent ofinspections conducted.

c) Soil has been demonstrated to be not corrosive for the material type.

* The inspection scope for piping that does not meet Category C or E inspectionschedule reguirements is 10 percent, NTE 23 inspections, in years 30 to 40: 12 percent,NTE 30 inspections, in years 40 to 50: and 15 percent, NTE 38 inspections, in years 50to 60.

1fThe AF system underground stainless steel piping located in a vault will undergo twoinsarections each 10-yer inspection period.


The OW system underground piping will undergo 2% NTE 4 inspection each 10-yearinspection period.

Cathodic protection shall be operational (available) at least 85 percent of the time sinceeither 10 years prior to the period of extended operation or since installation orrefurbishment, whichever is shorter.

Cathodic protection shall provide effective protection for buried piping at least 80percent of the time since either 10 years prior to the period of extended operation orsince installation or refurbishment, whichever is shorter.

As found results of annual surveys are to be used to demonstrate locations within theplant's population of buried pipe where cathodic protection acceptance criteria have, orhave not, been met.

Indicate that adverse indications discovered during the monitoring of the cathodicprotection system may warrant increased monitoring of the cathodic protection systemand/or additional inspections.

Include examples of adverse indications discovered during piping inspections includingleaks, material thickness less than minimum, and general or local degradation ofcoatings that exposes the base material. The presence of coarse backfill within 6 inchesof a coated pipe or tank, with accompanying coating degradation, is considered anadverse condition.

Adverse indications that fail to meet the acceptance criteria described in this programrequire corrective actions for the repair or replacement of the affected component.

An analysis may be conRducted to determine the potential extent of the degradationobser-ed. Expansion of sample siz.e m.ay be limnited to the piping or taRnks .subject to theeobserved degradation mechanism.

If adverse indications are detected in safety related or hazmat piping, inspection samplesizes within the affected piping categories are doubled. If adverse indications are foundin the expanded sample, an analysis is conducted to determine the extent of conditionand extent of cause. the inspection .am.pl size is again doubled. This doubling of theinspect!in sample size continues until no more adverse co.nditions are found. The sizeof the follow-on inspections will be determined based on the extent of condition andextent of cause. The timing of the additional examinations should be based on theseverity of the degradation identified and should be commensurate with theconsequences of a leak or loss of function, but in all cases, the expanded sampleinspections should be completed within the 10-year interval in which the originaladverse condition was identified. Expansion of the sample size may be limited by theextent of piping subiect to the observed degradation mechanism. If adverse conditionsare extensive, inspections may be halted in an area of concern that is planned forreplacement, provided continued operation does not pose a significant hazard.

Define the scope of inspection for buried pipi uing the criteria in Section XI.M41Table 4a of NUFREG 1801, Revisio 2. The scope Of inspection is O tho

codtOnf cathodic protection, backfill and- coa-ting of the piping


Ensure the scope of inpcinicossWhen the cathodic protection systomA doosnoMeot operability requ1irem:ents Or the backfill doeS not Meet the bac-kfill -acceptance

crieri, a pcifed n Setinm X[MI Tabl ;;la o; f NiRE 1 80CZ1.Q Reqviionm 2L

p . . .. • n I i • 11 i i I i • A f I f I I i • i I iI.ac-h inspection Of urled piping w.ll exam..ne at least 1U feet ot p.png. if the entirelength of piping i6 less than 10 foot, inspect the entire length. Piping.,: oF each Materiatype mus6t be inspected. Regardless of the inspection scope prescribed by SectionXl.441 Table 4a of NUJREG 1801, Revision 2, the isetosmay be limited to 10preFnt of the pipin6 uRder coRnideration.

i

Regardlessq of the oniGAW1tion of the bhac-kfill and coatings, only one inspection is requiredof all bur~ied stainless steel safety related piping du1Frin each 10) year inpcto AitR;a

The safety related unRderground stainless, steel pipe in the auxiliar-' feedwater systemnMUMt be inspected once every ten years-.

During the inspection of buried piping, observe for brittle failure at flanges, connections,and joints due to frost heaving, soil stresses, or ground water effects.

Monitoring and Trending (Element 5)


di-eet-Direct the cathodic protection system engineer to trend results of the plant yardcathodic protection system annual surveys, so that changes in the effectiveness of thecathodic protection system and coating of buried piping can be verified.

Where wall thickness measurements are conducted, the results should be trended iffollow-up examinations are conducted.

Acceptance Criteria (Element 6)


The cathodic protection system pipe-to-soil potential when using a saturatedcopper/copper sulfate reference electrode must be between -850 mV instant off and -1200 mV. The cathodic protection system is operational (available) at least 85 percentof the time and provides effective protection for buried piping as evidenced by meetingthe acceptance criteria at least 80 percent of the time since either 10 years prior to theperiod of extended operation or since installation or refurbishment.

For coated piping, there should be no evidence of coating degradation. If coatingdegradation is present, it may be considered acceptable if it is determined to beinsignificant by an individual possessing a NACE Coating Inspector Program Level 2 or3 inspector qualification, or an individual has attended the Electric Power ResearchInstitute (EPRI) Comprehensive Coatings Course and completed the EPRI Buried PipeCondition Assessment and Repair Training Computer Based Training Course.pef-atefqualification, Gr OtheFrWie meeting the qu5alifications to e eatings as describedin 49 CER 192 and 195.


Where damage to the coating has been evaluated as significant and the damage wascaused by non-conforming backfill, an extent of condition evaluation should beconducted to ensure that the as-left condition of backfill in the vicinity of observeddamage will not lead to further degradation.

Backfill is acceptable if it is consistent with SP0169-2007 Section 5.2.3. Backfill that islocated within 6 inches of steel pipe that meets ASTM D 448-08 size number 67 isconsistent with the objectives of SP0169-2007.

For any hydrostatic tests credited by this program, the condition acceptance criteria isno visible indications of leakage and no drop in pressure within the isolated portion ofthe piping that is not accounted for by a temperature change in the test media orquantified leakage across test boundary valves"with-ut loakage", as requird• by 49CF=R 19P5.2302, may be met by demonstrating thttets pressure, as adjustedfotemperature, doeS nt var, during the test.

Detectonr ef Aging Efffects (Elemert 4) and Acceptance Criteria (Elemert 6)

ie tthe systemns wothese bried Or underelgrd piping Within the scope of ths progranm.The li st sheoud coentain whether the pope is fty 9Frelt o hazcrat frnf each pipingmaterial and sytema within the og.pe Of thi program. Indicate whether ore nt thecoating, backfill an d c athodi e psrotetin of this piing e in c-mpliano With NAREpSFh 169 des207 c anbdi the ether requirements f Se actriontd 41, Table 2a of N REiG 181,ReV*GueR 2.

Operating Experience

A 10-year review of plant operating experience shows 30 events which were associated withburied piping. Nine of these events were related to systems or components in scope of licenserenewal. All of these events were leaks shown to not be a result of corrosion of materials,making them not relevant to this program. The program includes availability, reliability,maintainability, and capacity measurement analyses, published in bi-annual Health Reports.The events described in the Health Reports are all attributed to causes other than corrosiondue to contact with an aggressive environment (most leaks were associated with mechanicaljoints).

The need to enhance the STP Buried Piping program was initially identified by INPO as anarea for improvement. Since that time, involvement with the industry has identified areas forprogram enhancement. Enhancement of the program is ongoing, utilizing guidance from NEI09-14 Revision 1, Guideline for the Management of Buried Piping Integrity, and industryoperating experience.

The following industry operating experience was reviewed to identify aging effects applicable toSTP.

In February 2005, a leak was detected in a 4-inch condensate storage supply line. The causeof the leak was microbiologically influenced corrosion (MIC) or under deposit corrosion. MICand under deposit corrosion are typically internal corrosion, and managed by the WaterChemistry program (B2.1.2) and verified with the One-Time Inspection program (B2.1.16).


In September 2005, a service water leak was discovered in a buried service water header. Theheader had been in service for 38 years. The cause of the leak was either failure of theexternal coating or damage caused by improper backfill. STP has a very fine grain of thenatural soil, and the installation specifications for backfilling require a backfill that is consistentwith ASTM D-448 08 size number 67. Considering this, there is a low probability that pipecoatings have sustained damage due to backfill. The cathodic protection system is operated inaccordance with NACE SP0169 and will assure that the piping has a low probability ofcorrosion, even in the event of coating degradation or failure.

In October 2007, degradation of essential service water piping was reported. The riser pipeleak was caused by a loss of pipe wall thickness due to external corrosion induced by the wetenvironment surrounding the unprotected carbon steel pipe. This degradation is not expectedat STP, as all steel and copper alloy piping managed by this program are coated andcathodically protected.

In February 2009, a leak was discovered on the return line to the condensate storage tank.The cause of the leak was coating degradation, probably due to the installation specificationnot containing restrictions on the type of backfill, allowing rocks in the backfill.

STP has a very fine grain of the natural soil, and the installation specifications for backfillingrequire a backfill that is consistent with ASTM D-448 08 size number 67. Considering this,there is a low probability that pipe coatings have sustained damage due to backfill. Plantspecifications will be enhanced to prevent rocks and debris from striking the pipe coatingsduring the backfill of piping. The cathodic protection system is operated in accordance withNACE SP0169 and will assure that the piping has a low probability of corrosion, even in theevent of coating degradation or failure.

In April 2009, a leak was discovered in an aluminum pipe where it went through a concretewall. This leak is not relevant to STP, as the plant has no buried aluminum piping that requiresmanagement by this program.

In June 2009, an active leak was discovered in buried piping associated with the condensatestorage tank. The leak was discovered because elevated levels of tritium were detected. Thecause of the through-wall leak was determined to be degradation of the protective moisturebarrier wrap, which allowed moisture to come in contact with the piping, resulting in externalcorrosion. STP inspected pipe coatings during installation, and verified an acceptablecondition of wrap as it was installed. The cathodic protection system is operated in accordancewith NACE SP0169 and will assure that the piping has a low probability of corrosion, even inthe event of coating degradation or failure. The inspection of high risk piping by this programcan be used to verify that this degradation is unlikely at STP.

The Buried Piping and Tanks Inspection program requires review of plant and industryoperating experiences for impacts to the program. This program ensures long-term strategiesto address Buried Piping and Tank Inspection are developed and implemented.

Conclusion

The continued implementation of the Buried Piping and Tanks Inspection program providesreasonable assurance that aging effects are managed such that the systems and componentswithin the scope of this program will continue to perform their intended functions consistent withthe current licensing basis for the period of extended operation.

Enclosure 2NOC-AE-1 4003149

Enclosure 2

STPNOC Regulatory Commitments


A4 LICENSE RENEWAL COMMITMENTSTable A4-1 identifies proposed actions committed to by STPNOC for STP Units 1 and 2 in its License Renewal Application. Theseand other actions are proposed regulatory commitments. This list will be revised, as necessary, in subsequent amendments toreflect changes resulting from NRC questions and STPNOC responses. STPNOC will utilize the STP commitment tracking system totrack regulatory commitments. The Condition Report (CR) number in the Implementation Schedule column of the table is forSTPNOC tracking purposes and is not part of the amended LRA.

Table A4-1 License Renewal CommitmentsItem # Comitment LR implementatin

Section Schedule

13 Enhance the Buried Piping and Tanks !npection program plant specifications to: B2.1.18 Start implementationduring the 10 years

" Lower coated piping carefully into a trench to avoid external coating damage. prior to the period of* Use proper storage and handling practices to prevent damage to pipe coating prior to extended operation.

installation. These practices include padded storage, use of proper slings for installation Inspections to beand ultraviolet light resistant topcoats. complete no later

* Over excavate trenches and use qualified backfill for bedding piping. Take care during than six months priorbackfilling to prevent rocks and debris from striking and damaging the pipe coating. to the PEO or the end

" Include the coating used for copper alloy buried piping in the coating database. The of the last refueling

coating system must be in accordance with NACE SP0169-2007, and will be used for outage prior to therepair or for new coatings of the buried copper alloy piping in the essential cooling water PEO, whichever

system. occurs later.

" Coat the portion of the essential cooling water system copper alloy piping directly CR 10-23268.embedded in backfill or directly encased in concrete, extending the coating 2 feet ormore above grade.

Enhance the Buried Piping and Tanks Inspection program procedures to:* Consider backfill located within 6 inches of the pipe, and consistent with ASTM D 448-

08 size number 67, acceptable. Backfill quality is determined through examinationduring the inspections conducted by the program. Backfill that does not meet theASTM criteria, during the initial and subsequent inspections of the program, isconsidered acceptable if the inspections of buried piping do not reveal evidence ofmechanical damage to the pipe coatings due to the backfill.

* Ensure the cathodic protection system survey is performed annually.


Table A4-1 License Renewal CommitmentsItem# " Commitment LRA piementation

S.Section Schedule.. *V :•.•".. .NV. . .. • :

* Monitor the output of the cathodic protection system rectifiers every 2 months. Themeasured current at each rectifier is recorded and compared against a target value.Following the completion of the plant yard cathodic protection system annual survey,record the current of the rectifier used to achieve an acceptable pipe/soil potential.That current will be the target current for the rectifier until the next annual survey. If thecurrent measured at the rectifier during the bimonthly monitoring deviates significantlyfrom the target value, a condition report should be created. The rectifier current shouldbe adjusted to an acceptable value. The results of the survey will be documented andtrended to identify degrading conditions. When degraded rectifier performance isidentified, documentation is required in accordance with the corrective action program.The system should not be operated outside of established acceptable limits for longerthan 90 days.

" Recommend increased monitoring of the cathodic protection system and/or additionalinspections if adverse indications are discovered during the monitoring of the cathodicprotection system.

* Evaluate the effectiveness of isolating fittings, continuity bonds and casing isolation,during the plant yard cathodic protection system annual survey. This may beaccomplished through electrical measurements.

* The personnel performing the Plant yard cathodic protection system annual surveymust be NACE-certified, certified by a site-approved trainincq procedure consistent withthe NACE requirements, or supervised by a NACE-certified inspector.

* Visually inspect buried piping and, if significant indications of degradation areobserved, the visual inspections are supplemented by surface and/or volumetric non-destructive testing.

" Define the inspection interval for the program directed inspections as every 10 years,beginning the 10 year interval prior to the period of extended operation.

* Select the buried and underground piping inspection locations based on risk,considering susceptibility to degradation and consequences of failure.

* The risk rankincq for underground pipingq should consider characteristics such ascoating type, coating condition, exact external environment, pipe contents, pipefunction, and flow characteristics within the pipe.


Table A4-1 License Renewal CommitmentsItem # Commitment : '. : LRA Implementation

:. .• ~ .. .Se• ction. Schedule ::...

" The risk rankinq should generally give piping systems that are backfilled usingqcompacted aggregate a higher inspection priority than comparable systems that arecompletely backfilled using controlled low strength material.

* External Corrosion Direct Assessment, as described in NACE Standard PracticeSP0502-2010, will be considered for use in identifying inspection locations.

* Credit opportunistic examinations of non-leaking pipes toward required examinations,only if they meet the risk ranking selection criteria.

* Guided wave ultrasonic, or other advanced inspection techniques should be used, ifpractical, for the purpose of determining piping locations that should be inspected.These inspections may not be used as substitutes for inspections required by theprogram.

" Credit an inspection of piping shared between Units 1 and 2 toward the requiredinspections Of GnIy one '-A.

" Examine any piping, valves and closure bolting exposed during inspections." Examine bolting for loss of material and loose or missing fasteners." Include two alternatives to directed inspections of the buried or underground piping

that is safety-related, hazmat or both. The first alternative is to hydrostatically test 25percent of the subject piping to 110 percent of the design pressure of any componentwithin the boundary with test pressure being held for eight hours on an interval not toexceed 5 years. The second is an internal inspection of 25 percent of the subjectpiping by a method capable of accurately determining pipe wall thickness on aninterval of every 10 years.

* Flow testing of the fire mains, as described in NFPA 25, 2011 Edition, to detectdegradation of the buried pipe in lieu of visual inspections of the fire protection systemburied and underground piping.

" Define "hazm. t pipe" a6 pipe that, during no.rmal o•pcatio, contain• fluids that, ireleased, would- be dtiealto the enVironment.

* Specify that each inspection will examine either the entire length of a run of pipe, or aminimum of 10 feet. If the entire run of pipe of that material type is less than 10 feet intotal length, then the entire run of pipe should be inspected. The inspection consists ofa 100 percent visual inspection of the exposed pipe.


Table A4-1 License Renewal Commitmentstem# ; 'commitment L•• Implementation

Section Schedule

* Specify that Category C inspections be used when the external cathodic protectionsystem for buried steel or copper alloy pipe meets the acceptance criteria. Category Cinspections are 0.5 percent Not-to-Exceed (NTE) two inspections of that piping perinspection period performed.

* Specify that Category E inspections be used when the cathodic protection system hasbeen installed but the portions of the piping covered by that system fail to meet theacceptance criteria. Category E inspections are 5 percent, NTE 10 inspections, inyears 30 to 40: 6 percent, NTE 15 inspections, in years 40 to 50: and 7.5 percent, NTE18 inspections, in years 50 to 60. The following condition must be present.

o Coatings and backfill are provided in accordance with STP backfillspecification.

o There have been no leaks in buried piping due to external corrosion and nosignificant coating degradation or metal loss in more than 10 percent ofinspections conducted.

o Soil has been demonstrated to be not corrosive for the material type.* Specify that inspection scope for piping that does not meet Category C or E inspection

schedule requirements is 10 percent, NTE 23 inspections, in years 30 to 40: 12percent, NTE 30 inspections, in years 40 to 50; and 15 percent, NTE 38 inspections, inyears 50 to 60.

* Specify that the AF system underground stainless steel piping located in a vault willundergo two inspections each 10-year inspection period.

* Specify that the OW system underground piping will undergo 2% NTE 4 inspectioneach 10-year inspection period.

* Include acceptance criteria for the cathodic protection to be operational (available) atleast 85 percent of the time since either 10 years prior to the period of extendedoperation or since installation or refurbishment, whichever is shorter.

* Include acceptance criteria for the cathodic protection system to provide protection forburied piping at least 80 percent of the time since either 10 years prior to the period ofextended operation or since installation or refurbishment, whichever is shorter.

• - Include examples of adverse indicationsdiscovered during piping inspections.* Repair or replacement of the affected component when adverse indications failing to

meet the acceptance criteria described in the proqram are discovered.


Table A4-1 License Renewal CommitmentsItem # Commitment LRA imple .nt.tion:~~4 • R mpeentatin

.. Sectibn Schedule

" Indicate that an analysis may be conducted to dcterMine the potential extent of thedegradation, A-hen it is observed.

* Double inspection sample sizes within the affected piping categories, when adverseindications are detected during inspection of safety related or hazmat bu-rid pipjnge. Ifadverse indications are found in the expanded sample, an analysis is conducted todetermine the extent of condition and extent of cause. The size of the follow-oninspections will be determined based on the extent of condition and extent of cause.The timing of the additional examinations should be based on the severity of thedegradation identified and should be commensurate with the consequences of a leakor loss of function, but in all cases, the expanded sample inspections should becompleted within the 10-year interval in which the original adverse condition wasidentified. the i-lnspcteon sample ize , again doubled. This doubling of the i..pctio,

sampe siZe continues until no more adverse conditions are found. If adverse

conditions are extensive, inspections may be halted in an area of concern that isplanned for replacement, provided continued operation does not pose a significanthazard. Expansion of sample size may be limited to the piping subject to the observeddegradation mechanism.

" Definc the scope Of inspection for buried piping using the criteria in NUREG 1801.The sco)pe Of inspection Will beP bhased_(_ on the condition Of cathodic protection, backfland coating of the piping. Ensure the Scope of inspection incre.ses the cho-,d-ich,-

protection system does not meet operability requirements, or when backfill is examinedand does not meet the backfill acceptance criteria.

-- Examine at least 10 feet Of piping during each inspection of buriedgind I--.if the entirelength piping is less than 10 feet, inspect the entiro longth; Of piping.

" Indica_;te that the inspections may be l1imited- to 10 percent of the piping underconsideration, per inspection *Rtepval, regardless of the inspection scope prescribedithe NUREG 1801 guidance-.

" Po-.fo-rm one inspectionA of all1 buried stainless steel safety related piping per npeto0 nte~Lak.

" Exam~ine at least 10 feet Of piping during each inspection Of underground pipfing. if theentire lenath of aiainco is less than 10 feet. iRnsact the en.tfire- IPenth.I

Enclosure 2NOC-AE-1 4003149Page 6 of 6

Table A4-1 License Renewal CommitmentsItem,# Commitment ! .RA :Ii ... ... : ..... L Implementation.: . . ..:.. .. :.•..•"•::. :. . ..., . ,.::•...: ... .. •, !.•. ,•x,.. :',•S e ctio n ',-... ,• S c h e~d u le.. .

...npec th, und. rgroud stainl•eG steel pipe in the auxiliary feedWat...• Stem. onceeach inspection inter~al.

* Observe for brittle failure at flanges, connections, and joints due to frost heaving, soilstresses, or ground water effects during inspection of buried piping.

" Require trendinq cathodic protection system annual surveys results.* Where wall thickness measurements are conducted, the results should be trended if

follow-up examinations are conducted.

" Specify that the cathodic protection system pine-to-soil potential when usinq asaturated copper/copper sulfate reference electrode must be between -850 mV instantoff and -1200 mV.

* Indicate that for coated piping, there should be no evidence of coating degradation. Ifcoating degradation is present, it may be considered acceptable if it is determined tobe insignificant by an individual possessing a NACE Coating Inspector Program Level2 or 3 inspector qualification, or an individual has attended the Electric PowerResearch Institute (EPRI) Comprehensive Coatingqs Course and completed the EPRIBuried Pipe Condition Assessment and Repair Training Computer Based TrainingCourseoperat.r qualification, Or other-wi-se meeting the qualifications to evaluatecoatings as described in 40 CFR 102 and 105.

* Specify where damage to the coating has been evaluated as significant and thedama-qe was caused by non-conforming backfill, an extent of condition evaluationshould be conducted to ensure that the as-left condition of backfill in the vicinity ofobserved damage will not lead to further degradation.

" Specify that backfill is acceptable if it is consistent with SP0169-2007 Section 5.2.3.Backfill that'is located within 6 inches of steel pipe that meets ASTM D 448-08 sizenumber 67 is consistent with the objectives of SP0169-2007.

* Indicate that for any hydrostatic tests credited by the program, the condition acceptancecriteria is no visible indications of leakagqe and no drop in pressure within the isolatedportion of the piping that is not accounted for by a temperature change in the test mediaor quantified leakage across test boundary valves."without leakage" may be met by

. G _ EPA... Nn 1.ra....tng na"•. the test pressure eas noA cange SgiGcaRy uin ..... t"est. [. I I

noc-ae-14003149 u. s. nuclear regulatory commission ... · the following provides the...

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