NRC Generic Letter 1988-01

NRC Generic Letter 1988-001: NRC Position on Ig SCC in BWR Austenitic Stainless Steel Piping

ML031430193
Person / Time
Issue date:	01/25/1988
From:	Office of Nuclear Reactor Regulation
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-nr GL-88-001
Download: ML031430193 (9)

NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping S"fiA-4 NIndex Site Map j FAQ I Help A Glossary I Contact Us l 7 7 Seawh AU.S. Nuclear Regulatory Commission [ jHome n Who We Are 1lIWhat We Do Nuclear l Nuclear n Radioactive ll PublicHome fl WhoWeA l W Reactors fl Materials fl Waste l InvolvementHome > Electronic Reading Room > Document Collections > Generic Communications > Generic Letters > 1988 > GL88001UNITED STATESNUCLEAR REGULATORY COMMISSIONWASHINGTON, D.C. 20055January 25, 1988TO ALL LICENSEES OF OPERATING BOILING WATER REACTORS (BWRS), AND HOLDERSOF CONSTRUCTION PERMITS FOR BWRSGentlemen:

SUBJECT: NRC POSITION ON IGSCC IN BWR AUSTENITIC STAINLESS STEEL PIPING(Generic Letter 88-01)Intergranular stress corrosion cracking (IGSCC) near weldments in BWRpiping has been occurring for almost 20 years. Early cases were inrelatively small diameter piping. In early 1982, cracking was identifiedin large-diameter piping in a recirculation system of an operating BWRplant in this country. Since then, extensive inspection programs havebeen conducted on BWR piping systems. These inspections have resulted inthe detection of significant numbers of cracked weldments in almost alloperating BWRs.A number of domestic and foreign BWR owners have replaced or plan toreplace piping systems that have experienced IGSCC with more resistantmaterial. Other owners are implementing countermeasures such as StressImprovement (SI) or Hydrogen Water Chemistry (HWC) to reduce thesusceptibility of the piping to IGSCC. In many cases, cracked weldmentshave been repaired by reinforcing them with weld overlay.Substantial efforts in research and development have been sponsored by theBWR Owners Group for IGSCC Research. The results of this program, alongwith other related work by vendors, consulting firms, and confirmatoryresearch sponsored by the NRC, have permitted the development of revisedStaff Positions regarding the IGSCC problems.The technical bases for these positions are detailed in NUREG-0313, Rev. 2"Technical Report on Material Selection and Process Guidelines for BWRCoolant Pressure Boundary Piping.' This revision to NUREG-0313 was amajor task in the staff long range plan to deal with BWR pipe crackingthat was presented to the Commission in SECY 84-301. This revisionincludes the relevant recommendations of the Piping Review Committee TaskGroup on Pipe Cracking issued as NUREG- 1061, Vol. 1, Report of USNRCPiping Review Committee,, and consideration of public comments on thatdocument. NUREG-0313, Rev. 2 describes the technical bases for the staffpositions on materials, processes, and primary coolant chemistry tominimize and control IGSCC problems. Inspection schedules and inspectionsample sizes are based on the susceptibility of weldments to initiationand propagation of IGSCC. Inspection schedules are comparable to thosespecified in Section XI of the ASME Boiler and Pressure Vessel Code incases where the piping material is IGSCC resistant. Varying amounts ofaugmented inspections are specified for piping with a greatersusceptibility to cracking, where there is less certainty about theeffectiveness of mitigation measures used, or in cases where repairs havebeen performed. When improved water chemistry control with hydrogenadditions is implemented, less augmentation of inspection schedules isrequired.-2-The purpose of this Generic Letter is to seek information regardinghttp:l/www.nrc.gov/reading-rmnldoc-collections/gen-comm/gen-letters/1988/g188001.html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping implementation of the new staff positions covering these technical areas.This Generic Letter supersedes Generic Letter 84-11, Inspection of BWRStainless Steel Piping."This Generic Letter applies to all BWR piping made of austenitic stainlesssteel that is four inches or larger in nominal diameter and containsreactor coolant at a temperature above 200xF during power operationregardless of Code classification. It also applies to reactor vesselattachments and appurtenances such as jet pump instrumentationpenetration assemblies and head spray and vent components.This Generic Letter does not apply to piping made of carbon steelclassified as P-1 by the ASME Boiler and Pressure Vessel Code.Staff Positions have been developed covering the following subjects:1. Staff Position on Materials2. Staff Position on Processes3. Staff Position on Water Chemistry4. Staff Position on Weld Overlay Reinforcement5. Staff Position on Partial Replacement6. Staff Position on Stress Improvement of Cracked Weldments7. Staff Position on Clamping Devices8. Staff Position on Crack Characterization and Repair Criteria9. Staff Position on Inspection Methods and Personnel10. Staff Position on Inspection Schedules11. Staff Position on Sample Expansion12. Staff Position on Leak Detection13. Staff Position on Reporting RequirementsThese Staff Positions are fully delineated in Attachment A to this letter.The staff continues to believe that replacing susceptible piping withIGSCC resistant materials will provide the greatest degree of assuranceagainst future cracking problems. Licensees may follow Generic Letter84-07, Procedural Guidance for Pipe Replacements at BWRs"; the staffencourages programs to replace degraded piping so as to reduce thepotential for cracking and to minimize the need for augmentedinspections. However, the staff recognizes that, if the staff positionsof this Generic Letter are implemented, adequate levels of pipingintegrity and reliability can be achieved. The staff believes thisGeneric Letter, together with the revision to NUREG-0313, will be of useto licensees in making sound decisions regarding IGSCC. Each weldment canbe evaluated considering its material, heat treatment history, stresslevel, chemical environment and surveillance program. This will provide abasis for a reasonable judgment regarding the long-term acceptability ofthat weldment. Considering that each piping system has many weldments andeach plant has many piping systems, the entire problem must be evaluatedin an integrated way.The Commission has determined that, unless appropriate remedial actionsare taken, BWR plants may not be in conformance with their current designand licensing bases, including 10 CFR 50, Appendix A, General DesignCriteria 4, 14, and 31.-3-Accordingly, pursuant to 10 CFR 50.54(f), you, as a BWR operating reactorlicensee or construction permit holder, are requested, to furnish, underoath or affirmation, your current plans relating to piping replacement,inspection, repair, and leakage detection. Your response should indicatewhether you intend to follow the staff positions included in this letter,or propose alternative measures. This information is needed for theCommission to determine whether an operating license should be issued, orif you hold an operating license, whether it should be modified orrevoked.An acceptable response to this letter would include the following specificitems:1. Your current plans regarding pipe replacement and/or other measurestaken or to be taken to mitigate IGSCC and provide assurance of continuedhttp://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/I 988/gl8800 1.html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping long term piping integrity and reliability.2. An Inservice Inspection (ISI) Program to be implemented at the nextrefueling outage for austenitic stainless steel piping covered under thescope of this letter that conforms to the staff positions on inspectionschedules, methods and personnel, and sample expansion included in thisletter.3. A change to the Technical Specifications to include a statement in thesection on ISI that the Inservice Inspection Program for piping covered bythe scope of this letter will be in conformance with the staff positionson schedule, methods and personnel, and sample expansion included in thisletter (see enclosed model BWR Standard Technical Specification). It isrecognized that the Inservice Inspection and Testing sections may beremoved from the Technical Specifications in the future in line with theTechnical Specifications Improvement programs. In this case, thisrequirement shall remain with the ISI section when it is included in analternative document.4. Confirmation of your plans to ensure that the Technical Specificationrelated to leakage detection will be in conformance with the staffposition on leak detection included in this letter.5. In accordance with 10CFR50.55a(o), your plans to notify the NRC of anyflaws identified that do not meet IWB-3500 criteria of Section XI of theCode for continued operation without evaluation, or a change found in thecondition of the welds previously known to be cracked, and yourevaluation of the flaws for continued operation and/or your repair plans.Licensees and construction permit holders for BWR plants are requested torespond to this generic letter within 180 days of receipt of this letter.NRC review of your submittal of information in response to this letter isnot subject to fees under the provisions of 10 CFR 170. However, shouldyou, as part of your response or in a subsequent submittal, include anapplication for license amendment or other action requiring NRC approval,it is subject to the fee requirements of 10 CFR 170 with remittance of anapplication fee of $150 per application (Sections 170.12(c) and 170.21)and subsequent semi-annual payments until the review is completed or theceiling in Section 170.21 is reached.-4-This request for information was approved by the Office of Management andBudget under clearance number 3150-0011 which expires December 31, 1989.Comments on burden and duplication may be directed to the Office ofManagement and Budget, Reports Management Room 3208, New Executive OfficeBuilding, Washington, D.C. 20503.

Sincerely,Frank J. Miraglia, Jr.Associate Director for ProjectsOffice of Nuclear Reactor Regulation

Enclosures:

1. Staff Positions on IGSCC In BWR Austenitic Stainless Steel Piping2. Model BWR Standard Technical Specification for Item 3 of this GenericLetter3. NUREG-0313, Revision 2(ATTACHMENT A)STAFF POSITIONS ON IGSCC IN BWR AUSTENITIC STAINLESS STEEL PIPINGScopeThese Staff Positions apply to all BWR piping made of austenitic stainlesssteel that is four inches or larger in nominal diameter and containsreactor coolant at a temperature above 200xF during power operationhttp://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/I 988/gl8 8001 .html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping regardless of Code classification. It also applies to reactor vesselattachments and appurtenances such as jet pump instrumentationpenetration assemblies and head spray and vent components.This Generic Letter does not apply to piping made of carbon steelclassified as P-1 by the ASME Boiler and Pressure Vessel Code.Staff Position on MaterialsMaterials considered to be resistant to sensitization and IGSCC in BWRpiping systems are:(1) Low carbon wrought austenitic stainless steel, which includes types304L, 304NG, 316NG and similar low carbon grades with a maximum carboncontent of 0.035%. Type 347, as modified for nuclear use, will beresistant with somewhat higher carbon content, the usual maximum of 0.04%is adequate. These materials must be tested for resistance tosensitization in accordance with ASTM A262-A or -EI or equivalentstandard.(2) Low carbon weld metal, including types 308L, 316L, 309L and similargrades, with a maximum carbon content of 0.035% and a minimum of 7.5%ferrite (or 7.5 FN) as deposited. Low carbon weld metal especiallydeveloped for joining modified type 347 Is also resistant as deposited.Welds joining resistant material that meet the ASME Boiler and PressureVessel Code requirement of 5% ferrite (or 5 FN) but are below 7.5%ferrite (or 7.5 N) may be sufficiently resistant, depending on carboncontent and other factors. These will be evaluated on an individual casebasis.(3) Piping weldments are considered resistant to IGSCC if the weld heataffected zone on the inside of the pipe is protected by a cladding ofresistant weld metal. This is often referred to as corrosion resistantcladding (CRC).(4) Cast austenitic stainless steel with a maximum of 0.035% carbon and aminimum of 7.5% ferrite (or 7.5 FN). Weld joints between resistant pipingand cast valve or pump bodies that do not meet these requirements areconsidered to be special cases, and are covered in the Staff Position onInspection Schedules below.(5) Austenitic stainless steel piping that does not meet the requirementsof (1) above is considered to be resistant if it is given a solution heattreatment after welding.-2-(6) Other austenitic materials, including nickel base alloys such asInconel 600, will be evaluated on an individual case basis. Inconel 82 isthe only commonly used nickel base weld metal considered to be resistant.It is the staff position that no austenitic material is resistant tocracking in the presence of a crevice, such as formed by a partialpenetration weld, where the crevice is exposed to reactor coolant.Staff Position on ProcessesThe processes considered to provide resistance to IGSCC in BWR pipingwelds are:(1) Solution Heat Treatment SHT)(2) Heat Sink Welding HSW)Either of these two processes will upgrade non-resistant material to IGSCCCategory A (see Table 1)(3) Stress Improvement (SI)Either of the following processes will upgrade non-resistant material toIGSCC Category B or C (See Table 1)http://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/1 988/gl8800 1.html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping a. Induction Heating Stress Improvement (IHSI)b. Mechanical Stress Improvement Process (MSIP)Last pass heat sink welding (LPHSW) is not considered to be fullyeffective.Staff Position on Water ChemistryThe use of hydrogen water chemistry, together with stringent controls onconductivity, will inhibit the initiation and growth of IGSCC. However,the responses of BWRs to hydrogen injection differs from plant to plant,and the development and verification of a generic HWC specification isnot yet complete. For these reasons, reductions in piping inspectionfrequencey based on the use of HWC will be considered on an individualcase bases at the present time. Staff criteria for evaluating theeffectiveness of water chemistry improvements are under development, andwill be available prior to general use of the HWC option. If fullyeffective HWC is maintained, a factor Categories B, C, D, and Eweldments. (See Table 1)Staff Position on Weld Overlay ReinforcementCracked weldments that are reinforced with weld overlay are acceptable forshort-term operation, and may be considered for longer term operationprovided:(1) The overlayed weldments are in conformance with the criteria of IWB3600 of Section XI of the 1986 Edition of the ASME Boiler and PressureVessel Code, and-3-(2) they are inspected in conformance with the Staff Position onInspection Methods and Personnel, by UT examiners and proceduresqualified to inspect overlayed welds.Staff Position on Partial ReplacementIf portions of cracked piping are replaced in the course of repair, thereplaced portions will be subjected to inservice inspection requirementsthat will depend on the materials and processes used. All relevant staffpositions of this Generic Letter will apply.Staff Position on Stress Improvement SI of Cracked WeldmentsStress Improvement is also considered to be an effective mitigationprocess when applied to weldments with short or shallow cracks.Specifically, welds with cracks that are no longer than 10% of thecircumference, and are no deeper than 30% of the wall thickness will beconsidered to be mitigated by SI.SI is only considered to be effective if it is followed by a qualified UTexamination, and if cracks are found, they must be sized both in depth andlength, by procedures and personnel qualified to perform sizingevaluations:Staff Position on Clamping DevicesClamping devices may be used for temporary reinforcement of crackedweldments. Each case must be reviewed and approved on an individualbasis.Staff Position on Crack Evaluation and Repair Criteria.Methods and criteria for crack evaluation and repair should be inconformance with IBW-3600 of Section XI of the 1986 Edition of the ASMEBoiler and Pressure Vessel Code.Evaluation of cracks for continued operation without repair requires thatcrack growth calculation be performed. As some details are not yetprovided in the Code, the following will be acceptable to the staff.http://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/I 988/gl88001 .html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping The crack growth rate da/dt) selected for use by the staff is expressedas:da/dt = 3.590 x lOE-8 x K(I)**2.161 inches per hourwhereK(I) is the applied stress intensity factor (Ksi

• SQRT(in))Linear elastic solutions for KI are required for crack growthcalculations. Any standard method is acceptable, for example, thosedescribed in the ASME Boiler and Pressure Vessel Code,Section XI,Appendix A. The axial residual stress distribution considered acceptableby the staff for large diameter pipes (12 inches and larger) is describedby the following nondimensional expression.-4-e/e(i) = SUM(from j=0 to j=4) of e(j) E**jwhereeo = 1.0el = 6.920e2 = 8.687e3 = 0.480e4 = -2.027E = x/teCi) = stress magnitude at E = 0 (inner surface)The above formula permits calculation of the residual stress value at anypoint x) through the vessel wall thickness (t) as a function of the peakresidual stress value at the inside diameter (ID), e(i).Technical basis and additional discussion related to evaluation and repairare given in NUREG 0313 Revision 2.Staff Position on Inspection Methods and PersonnelExaminations performed under the Scope of this letter should comply withthe applicable Edition and Addenda of the ASME Code,Section XI, asspecified in paragraph (9), Inservice Inspection Requirements oflOCFR50.55a, Codes and Standards, or as otherwise approved by the NRC.In addition, the detailed procedure, equipment and examination personnelshall be qualified by a formal program approved by the NRC such as thatbeing conducted in accordance with the NDE Coordination Plan agreed uponby NRC, EPRI, and the Boiling Water Reactor Owners Group for IGSCCResearch, being implemented at the EPRI NDE Center in Charlotte, NorthCarolina.A summary of the Staff Position on Inspection Schedules is given in Table1. Additional details and definitions are provided below. NUREG-0313,Rev. 2, Section 5 provides background information and technical bases.(1) Welds of resistant material, IGSCC Category A, shall as a minimum beexamined according to an extent and frequency comparable to that specifiedin applicable provisions of Section XI of the ASME Boiler and PressureVessel Code, as reflected in Table 1, attached. The selection of specificwelds to be included in this sample is the responsibility of theLicensee, and should include considerations of stress levels, pipingconfigurations, weld details, etc, and should represent his best judgementregarding selection of a representative and meaningful sample.The provisions of lOCFR50.55a, (b),(2),(ii) may be invoked if it isdetermined necessary to use the 1974 edition of the Code to permit ameaningful sample selection.http:/www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/1988/gl88001.html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping -5-(2) Although castings with higher carbon content than 0.035% are notconsidered to be resistant to sensitization, welds joining such castings(in the form of pump and valve bodies) to piping have been relativelyfree of IGSCC. This may be attributed to a favorable residual stressdistribution, as calculations have indicated. For this reason, weldsjoining resistant material to pumps and valves will be considered to beresistant welds, and included in IGSCC Category A. If extensive weldrepairs were performed the residual stress may be unfavorable, in whichcase such welds should be included in Category D.(3) Welds that have been treated by SI or reinforced by weld overlay thatare classified as IGSCC Category F because they do not meet theapplicable staff positions may be upgraded to Category E if no adversechange in crack condition is found after 4 successive examinations.Staff Position on Sample ExpansionIf one or more cracked welds in IGSCC Categories A, B, or C, are found bya sample inspection during the 10 year interval, an additional sample ofthe welds in that category shall be inspected, approximately equal innumber to the original sample. This additional sample should be similarin distribution (according to pipe size, system, and location) to theoriginal sample, unless it is determined that there is a technical reasonto select a different distribution. If any cracked welds are found inthis sample, all of the welds in that IGSCC Category should be inspected.If significant crack growth or additional cracks are found during theinspection of an IGSCC Category E weld, all other Category E welds shouldbe examined.a) Significant crack growth for overlayed welds is defined as crackextension to deeper than 75% of the original wall thickness, or forcracks originally deeper than 75% of the pipe wall, evidence of crackgrowth into the effective weld overlay.b) Significant crack growth for SI mitigated Category E welds is definedas growth to a length or depth exceeding the criteria for SI mitigation(either 10% of circumference in length or 30% of the wall in depth).Staff Position on Leak DetectionLeakage detection systems should be in conformance with Position C ofRegulatory Guide 1.45 "Reactor Coolant Pressure Boundary Leakage DetectionSystems,' or as otherwise previously approved by the NRC.1. Plant shutdown should be initiated for inspection and corrective actionwhen, within any period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or less, any leakage detection systemindicates an increase in rate of unidentified leakage in excess of 2 gpmor its equivalent, or when the total unidentified leakage attains a rateof 5 gpm or equivalent, whichever occurs first. For sump level monitoringsystems with fixed-measurement-interval methods, the level should bemonitored at approximately 4-hour intervals or less.-6-2. Unidentified leakage should include all leakage other than:(a) leakage into closed systems, such as pump seal or valve packing leaksthat are captured, flow metered, and conducted to a sump or collectiontank, or(b) leakage into the containment atmosphere from sources that are bothspecifically located and known either not to interfere with the operationsof unidentified leakage monitoring systems or not to be from a throughwall crack in the piping within the reactor coolant pressure boundary.3. For plants operating with any IGSCC Category D, E, F, or G welds, atleast one of the leakage measurement instruments associated with eachhttp://www.nrc.gov/reading-rmldoc-collections/gen-comm/gen-letters/l 988/gl88001 .html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Pipingsump shall be operable, and the outage time for inoperable instrumentsshall be limited to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or immediately initiate an orderlyshutdown.If any cracks are identified that do not meet the criteria for continuedoperation without evaluation given in Section XI of the Code, NRC approvalof flaw evaluations and/or repairs in accordance with IWB 3640 and IWA4130 is required before resumption of operation.TABLE 1SUMMARY OF INSPECTION SCHEDULES FOR BWR PIPING WELDMENTSDESCRIPTION OF WELDMENTS NOTESResistant MaterialsNon-resistant MatlsSI within 2 yrs ofoperation (1)Non-resistant MatlsSI after 2 yearsof operationNon-resistant MatlsNo SICrackedReinforced by weldoverlay or mitigatedby SICrackedInadequate orno repairNon-ResistantNot InspectedIGSCCCATEGORYA(1) B(1) C(1) D(1) (2)INSPECTIONEXTENT & SCHEDULE25% every 10 years(at least 12% in 6years)50% every 10 years(at least 25% in 6years)All within the next 2refueling cycles,then all every 10years (at least 50%in 6 years)All every 2 refuelingcycles50% next refuelingoutage, then all every2 refueling cyclesAll every refuelingoutageAll next refuelingoutageE(2) F(3) GNotes:(1) All welds in non-resistant material should be inspected after a stressimprovement process as part of the process. Schedules shown should befollowed after this initial inspection.(2) See recommendations for acceptable weld overlay reinforcements andstress improvement mitigation.(3) Welds that are not UT inspectable should be replaced, sleeved', orlocal leak detection applied. RT examination or visual inspection forleakage may also be considered.(Attachment B)Model BWR Standard Technical Specificationfor Item 3 of Generic Letter 88-01APPLICABILITYSURVEILLANCE REQUIREMENTS4.0.1 Surveillance Requirements shall be met during the OPERATIONALCONDITIONS or other conditions specified for individual LimitingConditions for Operation unless otherwise stated in an individualSurveillance Requirement.http://www.nrc.gov/reading-rm/doc-collections/gen-comm/gen-letters/1 98 8/gI8800 1 .html 03/13/2003 NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping .0.2 Each Surveillance Requirement shall be performed within thespecified time interval with:a. A maximum allowable extension not to exceed 25% of the surveillanceinterval, butb. The combined time interval for any 3 consecutive surveillance intervalsshall not exceed 3.25 times the specified surveillance interval.4.0.3 Failure to perform a Surveillance Requirement within the specifiedtime interval shall constitute a failure to meet the OPERABILITYrequirements for a Limiting Condition for Operation. Exceptions to theserequirements are stated in the individual Specifications. Surveillancerequirements do not have to be performed on inoperable equipment.4.0.4 Entry into an OPERATIONAL CONDITION or other specified applicablecondition shall not be made unless the Surveillance Requirement(s)associated with the Limiting Condition for Operation have been performedwithin the applicable surveillance interval or as otherwise specified.4.0.5 Surveillance Requirements for inservice inspection and testing ofASME Code Class 1, 2, & 3 components shall be applicable as follows:a. Inservice inspection of ASME Code Class 1, 2, and 3 components andinservice testing of ASME Code Class 1, 2, and 3 pumps and valves shall beperformed in accordance with Section XI of the ASME Boiler and PressureVessel Code and applicable Addenda as required by 10 CFR 50, Section50.55a(g), except where specific written relief has been granted by theCommission pursuant to 10 CFR 50, Section 50.55a(g) (6) (i)b. Surveillance intervals specified in Section XI of the ASME Boiler andPressure Vessel Code and applicable Addenda for the inservice inspectionand testing activities required by the ASME Boiler and Pressure VesselCode and applicable Addenda shall be applicable as follows in theseTechnical Specifications:ASME Boiler and Pressure Vessel Required frequenciesCode and applicable Addenda for performing inserviceterminology for inservice inspection and testinginspection and testing activities activitiesWeekly At least once per 7 daysMonthly At least once per 31 daysQuarterly or every 3 months At least once per 92 daysSemiannually or every 6 months At least once per 184 daysEvery 9 months At least once per 276 daysYearly or annually At least once per 366 daysGE-STS 3/4 0-2APPLICABILITYSURVEILLANCE REQUIREMENTS (Continued)c. The provisions of Specification 4.0.2 are applicable to the aboverequired frequencies for performing inservice inspection and testingactivities.d. Performance of the above inservice inspection and testing activitiesshall be in addition to other specified Surveillance Requirements.e. Nothing in the ASME Boiler and Pressure Vessel Code shall be construedto supersede the requirements of any Technical Specification.f. The Inservice Inspection Program for piping identified in NRC GenericLetter 88-01 shall be performed in accordance with the staff positions onschedule, methods, and personnel and sample expansion included in thisgeneric letter.GE-STS 3/4 0-3http://www.nrc.gov/reading-rmldoc-collections/gen-comm/gen-letters/1988/gl8800 l .html 03/13/2003