ML22167A003

Public Comment Resolution for Operational Leakage RIS

ML22167A003
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Issue date:	11/03/2022
From:	Office of Nuclear Reactor Regulation
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Analysis of Public Comments on DRAFT NRC REGULATORY ISSUE

SUMMARY

2021-XX OPERATIONAL LEAKAGE (ML21166A122)

Comments on the subject draft regulatory issue summary are avai lable electronically at the U.S. Nuclear Regulatory Commissions (NRCs) electronic Reading Room at http://www.nrc.gov/reading-rm/adams.html. From this page, the public can access the Agencywide Documents Access and Management System (ADAMS), whic h provides text and image files of the NRCs public documents. Comments were received from the following individuals or groups:

Submittal ADAMS No. Accession No. Commenter Affiliation Commenter Name 1 ML22074A263 Public Steven Bright 2 ML22074A264 Nuclear Energy Institute Dr. Jennifer Uhle 3 ML22075A095 Constellation Energy Generation, LLC Glen Kaegi 4 ML22075A097 Southern Nuclear Operating Company Cheryl Gayhear t 5 ML22075A098 Tennessee Valley Authority James Polickoski 6 ML22075A099 Public Megan Nally 7 ML22075A100 PSEG Nuclear, LLC David Mannai

This document lists each public comment by correspondence (i.e., submittal number). The NRC staff has summarized some comments and, in some cases, combined comments that raise similar issues. Where a comment is reproduced verbatim, the com ment is italicized. Each comment or comment summary is followed with the NRC staffs res ponse. In some instances, comments have been broken into segments for clarity. Each comme nt is referred to by the submittal number listed above and each comment from the corresp onding submittal.

Comment 1-1

1-1: The issue is whether the license holders should be able to use the original construction code applicable to their system to return the pressure vessel to operable standards or should license holders be required to use the codes currently applicable to them under 10 C.F.R. § 50.55a(g)(4,5). Under 10 C.F.R. § 50.55a(g)(4), during the initial 120-month service interval of the pressure vessel, in-service inspection standards are based on the standards referenced in 10 C.F.R. § 50.55a(a) that are ratified on the date 18 months before the date of issuance of the operating 3 license under this part, or 18 months before the date scheduled for initial loading of fuel. 10 C.F.R. § 50.55a(g)(4)(i). Similarly, for successive 120-month service interval pressure vessels, the applicable code will be the latest edition and addenda of the ASME Code incorporated by reference in paragraph (a) of this section 18 months before the start of the 120-month inspection interval. 10 C.F.R. § 50.55a(g)(4)(ii). While it would seem acceptable to use the original construction code for systems operating in their first 120-month service interval, it would seem imprudent for a license holder in subsequent 120-month inspection intervals to use the code applicable when the facility was built. For the safety of the public, license holders should be required to return their systems to the code applicable for their current inspection interval. As the RIS is stated currently, it appears that a license holder, who has been in operation for more than 120-months, would be required to reference the construction code that was applicable more than 120-months in the past. For example, a licensee that was midway through its first subsequent 120- month inspection interval, might be applying applicable construction codes that are more than sixteen years out of date. The applicable code would be the code that was in place eighteen months before the initial 120-month inspection interval. The hypothetical licensee is sixty months into its first subsequent inspection interval for a total of 198 months since the adoption of the relevant code.

The RIS should be amended to require license holders to apply the code applicable to their current inspection interval. This amendment would increase safety for the public by requiring licensees to use the most up-to-date building codes with which the licensees have already been required to comply. Using the most up-to-date building codes increases safety by requiring the use of the most up-to-date materials and techniques. The adherence to older building codes could allow licensees to use materials and techniques that have been found unsafe and were eliminated with adoption of revised and newer building codes.

NRC Staff Response

The NRC staff notes this comment is out of scope for the regula tory issue summary (RIS),

because implementing the comments proposal to require licensee s to update their building code would require rulemaking.

The license or license amendment authorizing operation of the p articular system, structure, or component (SSC) establishes the licensees construction code for each SSC (generally American Society of Mechanical Engineers (ASME) Boiler and Pres sure Vessel Code (BPV Code),Section III). The current regulations in Title 10 of the Code of Federal Regulations (10 CFR) 50.55a, Codes and standards, paragraph (a)(1)(i) inc orporate by reference ASME BPV Code,Section III, 1963 Edition through the 1970 Winter Add enda and the 1971 Edition (Division 1) through the 2017 Edition (Division 1), subject to the conditions identified in the current 10 CFR50.55a(b)(1)(i)-(xii). These codes specify stand ards for the construction of nuclear facility components and supports, independent from loca l building codes. Licensees are not required to update their construction codes, though they ma y do so voluntarily. Rather, the update requirement the comment refers to is for the inservice i nspection (ISI) code ASME BPV Code,Section XI. A separate inservice examination and testing (IST) code, the ASME Operation and Maintenance Code, has similar update requirements in 10 CFR 50.55a(f).

Taken together, the ISI and IST codes, as incorporated by refer ence in 10 CFR 50.55a, define inspection, testing, and repair requirements. Thus, this RIS is clarifying that updated codes must be applied to a leaking component when it clarifies that ASME B PV Code,Section XI, the ISI code, applies to these SSCs "[t]hroughout the service life of a boiling or pressurized water-cooled nuclear power facility. The RIS indicates that licensee s have the option of replacing leaking components with new components that meet their construc tion code, but doing so would generally be more onerous than repairing the components even un der the most up-to-date ISI code, if a repair is possible.

No change was made to the RIS in response to the comment.

Comments 2-1, 3-1, 4-1, 7-2

2-1: The comments assert that there is no legally binding requiremen t mandating the exclusive use of ASME Code Section XI flaw acceptance and evaluation meth ods to determine operability in response to discovery of operation leakage in ASME Code Clas s 2 and 3 components. The comments state that the inservice inspection rules of Section X I of the ASME Code apply only to flaws discovered during Section XI inservice inspections and te sts, and thus the Section XI rules

2 do not apply to flaws identified at other times. Further, the c omments argue that the Commissions regulations in 10 CFR 50.55a do not expand the app licability of the flaw acceptance and evaluation requirements contained in Section XI to cover operational leakage.

In addition, the comments point out that the generic communicat ions and correspondence cited in the RIS (e.g., Generic Letter (GL) 90-05, the Reedy Letters, RIS 2005-20 and associated inspection manual chapters) do not establish legally binding re quirements. The comments also note there is no question that if a licensee is going to undert ake a repair or replacement activity on a Class 2 or 3 component, that repair must conform to the re quirements of Article IWA-4000 (or an approved alternative). However, the comments disagree wi th the NRC position, asserting instead that operability determinations are evaluations of Tech nical Specifications (TS) compliance and do not constitute a repair or replacement activi ty.

NRC Staff Response

The NRC staff disagrees with these comments. 10 CFR 50.55a(g)(4 ) mandates the use of ASME BPV Code,Section XI, (or an approved code case) [t]hroug hout the service life of a boiling or pressurized water-cooled nuclear power facility. Th is means that licensees subject to 10 CFR 50.55a(g) are not, at any time during the service life o f their facility, permitted to deviate from the requirements of the applicable Section XI requirements, as incorporated by reference in § 50.55a, without relief, an approved alternative, or an exe mption. For SSCs covered by TS, the operability requirements est ablished by the limiting conditions for operations (LCOs) in the TS assume that the associated SSCs maintain structural integrit y. Thus, a challenge to the structural integrity of a TS SSC is a challenge to its specifie d safety function. As such, the NRC regulatory requirement is in the interrelation between 10 CFR 5 0.55a and the TS requiring a facility to ensure operability of an SSC experiencing operation al leakage. In addition, the TS establish the time to verify or restore structural integrity (i.e., compliance with 10 CFR 50.55a(g))

for SSCs rendered inoperable due to operational leakage through the TS completion time. Thus, 10 CFR 50.55a and the TS establish the structural integrity req uirements for Class 1, 2, and 3 SSCs, and the NRC has documented this longstanding regulatory p osition in generic communications, other NRC letters, and NRC inspector guidance f or more than 30 years.

The comments assert that the NRC did not intend its regulations in 10 CFR 50.55a to apply to operational leakage. The NRC position on the implementation of 10 CFR 50.55a for operational leakage has been documented over the past four decades in multi ple regulatory actions completed to grant relief requests to licensees, where appropri ate, and to take enforcement action to ensure that agency requirements are met. To provide e ffective and efficient oversight, agency guidance documents for both NRC inspectors and operating reactor licensees have consistently articulated this position. This RIS again highligh ts to licensees the NRCs position in this regard.

Flaw Evaluation versus Repair/Replacement and GL 90-05

Under 10 CFR 50.55a(g), licensees are required to implement Sec tion XI of the ASME BPV Code throughout the service life of the plant for ASME Code Cla ss 1, 2, and 3 SSCs. Before the NRC staff issued GL 90-05, Guidance for Performing Temporary N on-Code Repair of ASME Code Class 1, 2, and 3 Piping, dated June 15, 1990 (ML03114059 0), the clear understanding of the NRC staff and licensees was that through-wall leakage discovered during operation required a repair/replacement activity in accordance with IWA-4 000. GL 90-05, for the first time, provided generic guidance on circumstances in which the NRC sta ff would consider granting a request for relief from the requirement to perform such a repai r/replacement. Typically, under Section XI when a flaw is visually identified, IWB/C/D-3000 pro vides acceptance criteria and

3 options for licensees to allow continued service of a component. For example, no flaw in Class 2 or 3 piping can remain in service if it exceeds 75 percent thro ugh-wall per IWC/D-3642. The NRC staffs position on this matter, as documented in GL 90-05 and this RIS, is consistent with the acceptance criteria in Section XI for flaws in piping. This RIS defines operational leakage as leakage through a flaw in the pressure-retaining boundary of an ASME BPV Code Class 1, 2, or 3 SSC. For example, through-wall leakage clearly does not meet the 75 percent maximum acceptance criteria of IWB/C/D-3642. Thus, before GL 90-05 was issued, no additional evaluation was needed once leakage was determined to be through -wall because an IWA-4000 repair/replacement activity was clearly required to address the flaw and restore structural integrity.

Although the scope of GL 90-05 encompasses flaws other than ope rational leakage, it frequently uses leakage as an example of the kind of flaws that require repair/replacement activity under IWA-4000. Further, GL 90-05 specifically relies on ASME Code requirements to establish its scope: leakage through a flange gasket is not co nsidered to be a flaw in the piping by Section XI of the ASME Code and is excluded. Note that GL 9 0-05 specifies that it was only an option for ASME Code flaws in ASME Class 3 components for wh ich repairs required by the ASME Code would force the plant to shut down because of TS timi ng requirements: if the affected section of piping can be isolated for completing a cod e repair within the time period permitted by the limiting condition for operation (LCO) without a plant shutdown, the licensee is required to perform a code repair. Thus, GL 90-05, for the fir st time, provided generic guidance for licensees on options to avoid a shutdown otherwise required under their TS in response to ASME Code flaws (e.g., leakage discovered during operation).

After GL 90-05 was issued, in the 1996 Edition of the ASME BPV Code, IWA-4110 was revised to state that [t]he requirements of this Article [IWA-4000] ap ply regardless of the reason for the repair/replacement activity[Endnote]4 or the method that detected the condition requiring the repair/replacement activity. Endnote 4 explains that the reaso ns for repair/replacement activities may include (1) discrepancies detected during inserv ice inspection, maintenance, or service, (2) damage, or (3) failure during service. Shortly aft er the 1996 revision to IWA-4110, additional alternatives to repair/replacement activities were m ade available to evaluate operational leakage flaws (e.g., ASME BPV Code Cases N-513, iss ued in 1997, and N-705, issued in 2006). The use of these ASME Code alternatives for AS ME BPV Code Class 2 and 3 components is for temporary acceptance of flaws, including thro ugh-wall flaws, without performing a repair/replacement activity until the next schedul ed refueling outage.

The NRC staff provides the following clarification in response to the comment that operability determinations are evaluations of TS compliance, and do not con stitute a repair or replacement activity. Thus, the requirements of Article IWA-4000 do not gov ern operability determinations.

The NRC staffs position, consistently stated since at least GL 90-05, is that a flaw found in an ASME BPV Code Class 1, 2, or 3 SSC under the scope of 10 CFR 50.55a(g) constitutes a discrepancy detected during service (potentially a result of da mage) and an indication of potential failure during service (i.e., a challenge to TS opera bility). As indicated in GL 90-05, under some circumstances, non-through-wall flaws that meet Sect ion XI acceptance criteria may not require repair/replacement under IWA-4000 to ensure tha t they can perform a TS-required function. For through-wall flaws (e.g., operational leakage), GL 90-05 states that IWA-4000 would apply and the only other option to demonstrate T S operability is relief from IWA-4000. Therefore, the NRC staffs position, clarified in the RIS, is the same as the position described in GL 90-05: For SSCs required to be operable by TS, the operability requirements established by the LCOs in the TS rely on the associated SSCs m aintaining structural integrity, and 10 CFR 50.55a(g) establishes the NRC regulatory requirement that Section XI must be

4 used to ensure structural integrity for ASME BPV Code Class 1, 2, and 3 SSCs throughout the service life of the plant. In the special case of operational l eakage, no additional evaluation is required to determine that Section XI, Article IWA-4000, or NRC -approved Code Cases must be followed to verify structural integrity and demonstrate operabi lity. TS LCOs establish time limits for completing these activities in addition to the timeframes o therwise established by licensees corrective action or inservice inspection programs.

As explained below, this NRC posit ion is clearly described in l etters, generic communications, and inspection manuals. Further, the NRC implements this positi on through authorization of alternatives and relief requests, as well as the finding of vio lations in cases of noncompliance.

The Reedy Letters

The Reedy Letters clearly restate the NRC policy on this issue in letters from the Director of the Office of Nuclear Reactor Regulation and the Executive Director of Operations for the NRC, with concurrence from the Office of the General Counsel and the NRC Chairman at the time of issuance. Mr. Reedy was the former Chairman of the Subcommittee on Nuclear Power, ASME Section III, and had a series of communications with the NRC du ring the early and mid-1990s on these issues. These specific letters are significant in that they directly answer the question posed by this comment in 1996 for the very same issue raised du ring that timeframe concerning the regulatory requirements for operational leakage. The NRC st affs response provided in the February 20, 1996, letter (ML20006H277) was as follows:

Section 50.55a, paragraph (g)(4) states, in part, that [t]hrou ghout the service life of a boiling or pressurized water-cooled nuclear power facility, components (including supports) which are classified as ASME Code Class 1, Class 2 and Class 3 must meet the requirements, except design and access pr ovisions and preservice examination requirements, set forth in Section XI... As such, the regulations would not be satisfied if deterioration has caused a breach (i.e., leakage) in the wall of components within the scope of S ection 50.55a. That is, if a pipe has a through-wall defect that causes a leak, the n the pipe obviously has a flaw in it and a licensee could not demonstrate that the structural integrity of the component meets the flaw a cceptance criteria of Section XI, IWX-3000 (See 3[a] response). Arguments that Code references do not spec ifically require the defect causing a leak to be characterized and flaw evaluati on to be performed are insufficient for determining operability. Part 50, Appendix B, Criterion XVI, Corrective Measures, would require further eva luation of the deterioration to ascertain if the system, subsystem, or compone nt has sufficient safety margin and to ensure that other design basis and regulat ory requirements are met (e.g., Appendix A, General Criteria 14, 15, 31, 36, 37, 45, 46, and 51, plant SARs, plant technical specifications, etc.).

Additionally, the Reedy Letters explain in the 3(a) response:

ASME Code Inquiry 92-005, March 10, 1992, states corrective mea sures are required if a leak is found during a pressure test and the acce ptance criteria of IWX-3000 are exceeded and that for leakage found during normal plant operation,Section XI, IWA-5250(a) does not apply. However, lea kage found during plant operation brings into question the capability of a system, subsystem, or component to fulfill its safety function (i.e., operability).

5 The interpretation could mislead a licensee to conclude that it should take different actions if a leak is discovered by an operator during rounds rather than during the conduction of an inservice leak test because of the difference between the code interpretation and the guidance in GL 91-18. As a resu lt, a nonconforming condition could remain indeterminable for an exte nded period of time.

If a licensee has reason to believe that it would fail a requir ed inservice test, such as an inservice leakage test, it should take corrective actions as if the test had identified the failed condition and declare the system inoperab le when the acceptance criteria for such a test were not satisfied.

Of note, in the RIS, the NRC staff explains, [t]his RIS emphas izes that operational leakage must be addressed in the same manner as leakage detected during an ASME BPV Code,Section XI, pressure test.

In the June 12, 1996, letter to Mr. Reedy (ML20112K084), the Ex ecutive Director of Operations for the NRC reaffirmed the NRC position above in response to a follow-up letter from Mr. Reedy.

The Executive Director also not ed the NRC staffs position that ASME interpretations are not part of the regulations. Further, he explained that NRC regulat ions permit the use of alternatives, including those that may be based on engineering judgment. However, the NRC is responsible for ensuring that 10 CFR is effectively implemented and that alternatives to the regulations are reviewed and approved by the NRC staff before b eing used by a licensee. The Office of General Counsel and the NRC Chairman concurred with t his letter. The Reedy letters clearly state the NRC position on operational leakage as concurred with by the full staff management chain at the agency.

Generic Communications

The NRC position on the regulatory requirements for operational leakage have been documented consistently through NRC inspection manuals and gene ric communications over the past 30 plus years. The following quotes from each of these documents are provided to highlight the consistency of the regulatory position.

GL 90-05 states in part the following:

Section XI of the ASME Boiler and Pressure Vessel Code (hereaft er called the code) specifies code -acceptable repair methods for flaws that exceed code acceptance limits in piping that is in service. A code repair i s required to restore the structural integrity of flawed ASME Code piping, independen t of the operational mode of the plant when the flaw is detected.

GL 91-18, Information to Licensees Regarding Two NRC Inspectio n Manual Sections on Resolution of Degraded and Nonconforming Conditions and on Oper ability, dated November 7, 1991 (ML031140549) withdrawn May 20, 2016 (81 FR 31 969), includes NRC Inspection Manual Part 9900: Technical Guidance, Resolution of Degraded and Nonconforming Conditions, which states the following:

6.15 Operational Leakage Furthermore, the regulations and TS require that the structural integrity of ASME Code Class 1, 2, and 3 components be maintained according to Se ction XI of the

6 ASME Code. If a leak is discovered in a Class 1, 2, or 3 compon ent in the conduct of inservice inspections, maintenance activities, or du ring plant operation, IWA-5250 of Section XI requires corrective measures be taken based on repair or replacement in accordance with Section XI. In addi tion, a through-wall flaw does not meet the acceptance criteria in IWB-3600.

Upon discovery of leakage from a Class 1, 2, or 3 component pre ssure boundary (i.e., pipe wall, valve body, pump casing, etc.) the licensee s hould declare the component inoperable. The only exception is for Class 3 moderat e energy piping as discussed in Generic Letter 90-05. For Class 3 moderate ener gy piping, the licensee may treat the system containing the through-wall flaw( s), evaluated and found to meet the acceptance criteria in Generic Letter 90-05, as operable until relief is obtained from the NRC.

NRC RIS 2005-20, Revision 0, Revision to Guidance Formerly Con tained in NRC Generic Letter 91-18, issued September 26, 2005 (ML052020424), which superseded GL 91-18, and Inspection Manual Part 9900, issued September 26, 2005 (ML052060365). The 2005 revision of Part 9900 states the following:

C.11 Flaw Evaluation In accordance with 10 CFR 50.55a(g), structural integrity must be maintained in conformance with ASME Code Section XI for those parts of a syst em that are subject to Code requirements. The Code contains rules describin g acceptable means of inspecting welds in piping, vessels, and areas of high -stress concentration. The Code also specifies acceptable flaw sizes ba sed on the material type, location, and service of the system within which the flaw is discovered. If the flaw exceeds the generally acceptable limits, the Code also describes an alternate method by which a refined calculation ma y be performed to evaluate the acceptability of the flaw. At no time does the Code allow an unrepaired through-wall flaw to be returned to service. If a fl aw is discovered by any means (including surveillance, maintenance activity, or ins ervice inspection) in a system subject to Code requirements (whether during normal plant operation, plant transition, or shutdown operation), the flaw m ust be promptly evaluated using Code rules. If the flaw is through-wall or does not meet the limits established by the Code, the component and part of the system c ontaining the flaw is inoperable.

Evidence of leakage from the pressure boundary indicates the pr esence of a through-wall flaw. It may be possible to use visual methods to determine the exterior dimension(s) and orientation of a through-wall flaw in a leaking component. When the outside surface breaking dimension of a thr ough-wall flaw is small, the length and extent of the flaw inside the componen t wall may be quite long and potentially outside the limits established by the Code. For these reasons the component is declared inoperable while methods such as ultr asonic examination are performed to characterize the actual geometry of the through-wall flaw.

C.12 Operational Leakage from Code Class 1, 2, and 3 Components Existing regulations and TSs require that the structural integr ity of ASME Code Class 1, 2, and 3 components be maintained in accordance with t he ASME Code. In the case of specific types of degradation, other regul atory requirements

7 must also be met. If a leak is discovered in a Class 1, 2, or 3 component in the conduct of an inservice inspection, maintenance activity, or fa cility operation, corrective measures may require repair or replacement activities in accordance with IWA-4000 of Section XI. In addition, the leaking component should be evaluated for flaws according to IWB-3000, which addresses the analytical evaluation and acceptability criteria for flaws.

NRC RIS 2005-20, Revision 1, Revision to NRC Inspection Manual Part 9900 Technical Guidance (ML073440103), issued April 16, 2008, informed licens ees of revisions to Inspection Manual Part 9900 (ML073531346), also issued April 16, 2008, whi ch states the following:

C.11 Flaw Evaluation In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g), structural integrity must be maintained in conforman ce with American Society of Mechanical Engineers (ASME) Code Section XI for thos e parts of a system that are subject to ASME Code requirements. 10 CFR 50.55 a(g)(4) further requires, Throughout the service life of a boiling or pressurized watercooled nuclear power facility, components (including suppo rts) which are classified as ASME Code Class 1, Class 2, and Class 3 must meet the requirements, except design and access provisions and preservic e examination requirements, set forth in Section XI...

C.12 Operational Leakage from ASME Code Class 1, 2, and 3 Compo nents The regulations require that the structural integrity of ASME C ode Class 1, 2, and 3 components be maintained in accordance with the ASME Code or construction code acceptance standards. If a leak is discovered in a Class 1, 2, or 3 component while conducting an inservice inspection, maintenance activity, or during facility operation, any corrective measures to repair or replace the leaking component must be performed in accordance with IWA-4000 of Sect ion XI.

To evaluate the structural integrity of the leaking component, the licensee may use the criteria in Section XI of the ASME Code, the constructi on code, or any applicable ASME Code Case approved by the NRC.

Once a component is evaluated for structural integrity using cr iteria acceptable to the NRC staff as described herein, and determined to be unaccep table, the component has to be declared inoperable and the technical speci fication action statements for the applicable system must be followed.

The NRC has no specific guidance or generically approved alternatives for temporary repair of flaws (through-wall or non-through-wall) in system pressure boundary components other than piping in Class 1, 2, or 3 high-energy system components, or for Class 2 or 3 moderate-energy system componen ts.

Therefore, all such flaws in these components must be repaired in accordance with ASME Code requirements, or relief from ASME Code requireme nts must be requested of and approval obtained from the NRC.

NRC RIS 2005-20, Revision 2, Revision to NRC Inspection Manual Part 9900 Technical Guidance, issued June 15, 2015 (ML15106A484), announced NRC In spection Manual Chapter 0326, Operability Determinations and Functionality Assessments for Conditions Adverse to Quality or Safety, issued January 31, 2014 (ML13274A578), whic h states the following:

8 C.11 Flaw Evaluation In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g), structural integrity must be maintained in conforman ce with American Society of Mechanical Engineers (ASME) Code Section XI for thos e parts of a system that are subject to ASME Code requirements. 10 CFR 50.55 a(g)(4) further requires, Throughout the service life of a boiling or pressurized water-cooled nuclear power facility, components (including supp orts) which are classified as ASME Code Class 1, Class 2, and Class 3 must meet the requirements, except design and access provisions and preservic e examination requirements, set forth in Section XI

C.12 Operational Leakage from ASME Code Class 1, 2, and 3 Compo nents The regulations require that the structural integrity of ASME C ode Class 1, 2, and 3 components be maintained in accordance with the ASME Code or construction code acceptance standards. If a leak is discovered in a Class 1, 2, or 3 component while conducting an inservice inspection, maintenance activity, or during facility operation, any corrective measures to repair or replace the leaking component must be performed in accordance with IWA-4000 of Sect ion XI.

NRC Inspection Manual Chapter 0326, Operability Determinations, dated October 1, 2019 (ML19273A878), states the following:

08.12 Flaw Evaluation In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)/50.55a(f), structural integrity must be maintained in conformance with ASME Code Section XI for those parts of a system that are subje ct to ASME Code requirements. 10 CFR 50.55a(g)(4) further requires, Throu ghout the service life of a boiling or pressurized water-cooled nuclear p ower facility, components (including supports) which are classified as ASME Co de Class 1, Class 2, and Class 3 must meet the requirements, except design and access provisions and pre-service examination requirements, set forth in Section XI

If flaws are found in components for which ASME Section XI has no acceptance standards, then the construction code is to be used to establis h the acceptance standards. This is supported by Sub-article IWA-3100(b) which s tates if acceptance standards for a particular component, Examination Ca tegory, or examination method are not specified in this Division [Division 1] then flaws that exceed the acceptance standards for materials and welds specifi ed in the Section III Edition applicable to the construction of the compo nent shall be evaluated to determine disposition.

08.13 Operational Leakage from ASME Code Class 1, 2, and 3 Comp onents The NRC staff does not consider through-wall leakage in compone nts to be in accordance with the intent of the ASME Code or construction cod e, unless intentionally designed to be there such as sparger flow holes. Therefore, components with through-wall leakage would not meet ASME Sectio n XI or construction code requirements. Thus, unless a 100% through-wal l flaw is evaluated and found acceptable us ing an applicable methodology as described in the table above and in which all provisions are met includin g any additional

9 requirements or limitations i mposed (e.g. by the NRC approved code case), the system or component does not demonstrate structural integrity.

10 CFR 50.55a requires that the structural integrity of ASME Co de Class 1, 2, and 3 components be maintained in accordance with the ASME Code or construction code acceptance standards. If a leak is discovered in a Class 1, 2, or 3 component while conducting an in-service inspection, maint enance activity, refueling outage, or during facility operation, appropriate cor rective measures to repair or replace the leaking component must be performed in ac cordance with IWA-4000 of Section XI.

The NRC has been consistent throughout these documents in stati ng that 10 CFR 50.55a provides the regulatory requirements for flaw analysis and oper ational leakage. The NRC staff has explained that 10 CFR 50.55a requires that the structural i ntegrity of ASME Code Class 1, 2, and 3 components be maintained in accordance with the ASME C ode or construction code acceptance standards.

Operating Experience

In addition to extensive documentation, the NRC staffs positio n on operational leakage is supported by significant operating experience implementing the position, including documented violations and requests for alternatives and relief. The follow ing paragraphs provide a few example cases.

The following are examples of violations from requirements addr essing operational leakage.

Case 1:

NRC inspectors identified a Green noncited violation of Technic al Specification 3.7.4 because the licensee had one independent lo op of essential cooling water inoperable for longer than the allowed outage tim e of 7 days.

Specifically, on October 27, 2009, the licensee failed to initi ate actions to evaluate and repair a through-wall leak in the 30-inch essentia l cooling water return line from the Unit 2 train C component cooling water hea t exchanger, as required by American Society of Mechanical Engineers Boiler and Pressure Vessel Code, and in accordance with guidance contained in NRC G eneric Letter 90-05, Guidance for Performing Temporary Non-Code Repai r of ASME Code Class 1, 2, and 3 Piping. The inspectors questioned the l icensees reportability review and determined there was firm evidence tha t the through-wall leak caused the Unit 2 train C essential cooling w ater system to be inoperable for a period of 11 days instead of 8 days as init ially concluded by the licensee. The finding was more than minor because the throu gh-wall leak could have challenged the structural integrity of the piping an d it was associated with the Mitigating Systems Cornerstone attribute of configuration control and affected the cornerstone objective to ensure the av ailability, reliability, and capability of systems that respond to initiati ng events to prevent undesirable consequences. (IR 05000498-10-004, on 09/30/10, So uth Texas Project Electric Generating Station, Units 1 and 2, Integrated Inspection, issued November 2, 2010, ML103060091)

10 Case 2:

[A licensee] did not properly evaluate and document an adequate basis for operability, when relevant information was available that would have challenged the reasonable expectation of operability threshol d for a service water (SW) through-wall leak that degraded incrementally from w eepage on August 7, 2013, to a significantly larger leak on August 28, 20 13. The licensee completed a temporary non-code repair of the flaw with the inst allation of a weldolet on September 1, 2013, following NRC review and approva l of a relief request. (IR 05000443-13-004; 07/01/2013; Seabrook Station, Un it No. 1; Operability Determinations and Functionality Assessments &

IR 07200063-13-001, issued November 19, 2013, ML13323A634)

Case 3:

The inspector identified a non-cited violation of 10 CFR 50.55a (g)(4) for the licensees failure to evaluate an ASME code class piping leak i n the spent fuel pool piping, or perform evaluation prior to returning the syste m to service. A through-wall leak in the piping of the spent fuel pool cooling system downstream of valve SFP 23, spent fuel pool to the cask loading pit isolation valve, was identified in August 2009. The licensee closed [the condition report and work order] after completing clean-up of the boric acid cry stals. As of May 23, 2014, the exact location, size, and geometry of the fla w were still unknown. (IR 05000313-14-003; 05000368-14-003; on 04/01/2014-06/30/2014; Arkansas Nuclear One, Units 1 and 2, Integrated Ins pection Report; Post-Maintenance Testing, Radiological Environmental Mo nitoring Program; Inservice Inspection Activities, issued August 13, 20 14, ML14225A852)

The following paragraphs provide examples of proposed alternati ves for operational leakage identified outside of system pressure test. These approved requ ests for alternatives in accordance with 10 CFR 50.55a are consistent with the NRC staff s position that Section XI in combination with TS requires licensees to address operational l eakage in these components using Section XI methods. The NRC establishes the regulatory ba sis for each authorization of an alternative, and if there is no regulatory basis, the NRC st aff would not approve it. Thus, the approval of these alternatives demonstrates the application of the NRC staffs position that Section XI methods must be applied to verify structural integri ty.

Alternative 1:

On September 18, 2007, a nuclear plant operator conducting a ro utine plant walkdown noted minor leakage of approximately 5 drops per minut e in one of the two cement-lined 18" diameter, 0.375" nominal thickness, servic e water supply lines for the containment building [fan cooler units (FCUs)]. A s a result of this leak, a volumetric examination of the surrounding area was perf ormed and the results were evaluated against the requirements of ASME Code Ca se N-513-1.

Although this evaluation confirmed that the affected piping rem ains within the requirements of Code Case N-513-1, the calculated corrosion rat e does not support continued structural integrity through the remainder of the current operating cycle.

11 A weld repair/replacement fully compliant with the requirements of IWA-4000

[was] not practical. The affected piping section would need to be removed from service, which would result in three FCUs inoperable. [The lice nsees] Technical Specification 3.6.6 does not have a condition statement for tha t configuration, so it would require [the plant] to be shut down. [The licensee req uested a non-code repair to temporarily address the issue until] no later than th e next refueling outage. (Indian Point Nuclear Generating Unit No. 3Relief Req uest (RR)

No. 3-42 For Temporary Non-Code Repair of Service Water Pipe (T AC MD6821). Issued February 22, 2008, ML080280073)

Alternative 2

On August 14, 2014, a licensee identified a leak in an elbow on the east raw water (RW) piping. The leak required the plant to enter into Te chnical Specification (TS) 2.4(2)d. The licensee reported that the pinh ole leak was approximately 600 milliliters (ml) per hour on the inside of th e elbow towards the middle of the pipe. On August 15, 2014, the licensee reported t hat the leak rate had increased to 1100 ml/hour. The licensee stated that perform ing an ASME Code repair or replacement activity to correct the pinhole in t he RW elbow would require the plant to shut down (i.e., entry into a 24-hour hot shutdown TS requirement) and create a hardship based on the potential risks associated with unit cycling and emergent equipment issues incurred during shut down and startup evolutions. The licensee noted that the ASME Code does not include analytical evaluation criteria for acceptance of 100 percent th rough-wall flaws in pressure retaining base material of ferritic pipe or fittings. NRC Regulatory Guide 1.147, Revision 17, lnservice Inspection Code Case Acceptabili ty, ASME Section XI, Division 1, August 2014 (ADAMS Accession No. ML 13 339A689),

conditionally approves ASME Code Case N-513-3 which provides an alytical evaluation rules for temporary acceptance of 100 percent throug h-wall flaws in piping. The licensee noted that Code Case N-513-3 does not appl y to through-wall flaws located in elbows. [Therefore, the licensee requeste d authorization of a non-code repair.] (Fort Calhoun Station, Unit 1Relief Request RR-14, Proposed Alternative for Temporary Acceptance of a Phin Hole Le ak in Raw Water System 20-inch Elbow Loc ated in Room 19 of Auxiliary Building (TAC No. MF4643), issued November 19, 2014, ML14316A167)

Alternative 3

On November 3, 2016, a licensee detected a pinhole through-wall leak in the 3-inch diameter 31 fan cooler unit service water return line lo cated inside the vapor containment building. The licensee explained that the bas is for hardship is the requirements of TS 3.6.6, Containment Spray System and Con tainment Fan Cooler System, in which Action C states that an inoperable con tainment fan cooler unit must be restored to operable status within 7 days o r the plant must be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The licens ee recognized that an alternative is required in order to apply N-513-3 to ev aluate the leak for operability. [The licensee needed relief because it] was not ab le to satisfy the requirement of inspecting the full pipe circumference in accord ance with paragraph 2(b) of N-513-3 due to interference. (Indian Point N uclear Generating Unit No. 3Relief from the Requirements of the ASME Code Regard ing

12 Alternate IP3-RR-10 to the Full Circumferential Inspection Requ irement of Code Case N-513-3 (CAC No. MF8792), issued January 11, 2017, ML16358A444)

ASME BPV Code Case N-513

Many proposed alternatives over the past 20 years deal with ASM E BPV Code Case N-513, originally approved in August 1997. The latest version provides a generically approved alternative to repair/replacement activities through rules and criteria for evaluation and temporary acceptance of flaws, including through-wall flaws (i. e., operational leakage) identified in ASME BPV Code Class 2 and 3 piping systems. Use of ASME BPV Code Case N-513-x is allowed by the NRC until the next scheduled refueling outage, when an ASME Code repair is required. N-513 has been revised many times over the years to e xpand its applicability, as identified by the many licensees proposed alternatives. Note t hat an alternative is not necessary if a licensee can comp ly with the current NRC approved version of N-513-x at the time the leakage is identified.

N-513 is germane to the operational leakage regulatory requirem ent discussion because if there is no regulatory requirement to address operational leakage und er 10 CFR 50.55a(g) and Section XI, as the comment proposes, then there would be no nee d to use N-513-x or for a proposed alternative or regulatory relief in accordance with 10 CFR 50.55a to accept operational leakage, until the next scheduled refueling outage. In accordance with the comments position, the only regulatory requirement for a licen see to address leakage would be for compliance with the ASME Code,Section XI, system pressure test, typically performed at the end of an outage. However, the comments position is not co nsistent with current regulatory requirements, as described in the NRCs Federal Register (FR) notice (62 FR 63892) dated December 3rd, 1997, for the proposed rule to allow licensees to use ASME Co de Case N-513 as an option to address operational leakage. Specifically, the FR notice states the following:

Proposed § 50.55a(b)(2)(xvi) would permit licensees to use Code Case N-513, Evaluation Criteria for Temporary Acceptance of Flaws in Class 3 Piping,Section XI contains repair methods for pipes with a flaw exceed ing acceptable limits. These repairs restore the integrity of the flawed pipin g. There are certain cases, however, where a Section XI Code repair may be impractic al for a flaw detected during plant operation (i.e., a plant shutdown would b e required to effect the Code repair). For many safety-related piping systems, immed iate repair is required regardless of plant status. However, it has been deter mined that under certain conditions, temporary acceptance of flaws, including th rough-wall leaking, of low and moderate energy Class 3 piping is acceptable provide d that the conditions are met, and the repair is effected during the next outage. At present, licensees must request NRC staff approval to defer Section XI Code repair for this Class 3 moderate energy (200 °F, 275 psig) piping systems.

The preamble to the final rule reiterated the regulatory requir ements for operational leakage (64 FR 51370) dated September 22, 1999:

2.5.2.2 Flaws in Class 3 Piping.

Section 50.55a(b)(2)(xvi) in the proposed rule pertained to use of ASME Code Case N-513, Evaluation Criteria for Temporary Acceptance of Fl aws in Class 3 Piping, and Code Case N-523-1, Mechanical Clamping Devices fo r Class 2 and 3 Piping. These Code cases were developed to address criteria for temporary acceptance of flaws (including through-wall leaking) of moderat e energy Class 3

13 piping where a Section XI Code repair may be impractical for a flaw detected during plant operation (i.e., a plant shutdown would be require d to perform the Code repair). In the past, licens ees had to request NRC staff approval to defer Section XI Code repair for these Class 3 moderate energy (200 ° F, 275 psig) piping systems.

In addressing public comments in the final rule, the NRC staff further confirms its position on 10 CFR 50.55a(g),Section XI, and operability requirements:

The reason for incorporating the Code cases in the proposed rul e was that

§50.55a(g)(4) requires the application of Section XI during all phases of plant operation. Under Section XI structural and operability requirem ents, piping containing indications greater than 75 percent of the pipe thic kness are deemed unsatisfactory for continued service.

This language in the preamble for this rule is consistent with the NRC regulatory requirements for licensees to address operational leakage, as stated through out this response. In conclusion, the NRC regulatory requirement is in the interrelation between 50.55a and the TS for a facility to ensure operability for an SSC with operational leakage. As stat ed in the RIS:

If through wall operational leakage is observed from an ASME BP V Code Class 1, 2, or 3 SSC and the structural integrity of the SSC must be established to conclude that the system remains operable, then the methods described in the provisions of the a pplicable inservice inspection requirements, as specified in 10 CFR 50.55a(g), must be used. T hese methods require performance of a repair/replacement activity in accordance with the original construction code or ASME BPV Code,Section XI, or implementation of an NRC approved substitute for the repair/replacement activity (e.g., Code Case N-513, alternative s under 50.55a(z)) to verify structural integrity.

No change was made to the RIS in response to these comments.

Comments 2-2, 5-2, 7-3

The comments asserted that the expansion of the scope of Sectio n XI to cover operational leakage from Class 2 and 3 components would constitute backfitt ing.

NRC Staff Response

The NRC staff disagrees with these comments. The NRC position h as not changed regarding operational leakage through the language in the RIS as addresse d in response to comment 2-1.

Therefore, issuance of the RIS is not a backfit.

No change was made to the RIS in response to the comment.

Comments 2-3, 4-2, 5-1, 7-1

The comments express the concern that the RIS would unnecessari ly eliminate much needed flexibility that has been inherent in licensees approach to de termining the operability of Class 2 and 3 SSCs experiencing operational leakage. The comments prese nt some background information regarding operability determinations to support the ir position and explained their current approach to determining operability of Class 2 and 3 SS Cs experiencing operational leakage. Finally, the comments argue that the NRC must give different treatment to operability

14 determinations, corrective actions undertaken pursuant to Appen dix B of 10 CFR 50, and repair/replacement of Class 2 and 3 SSCs.

NRC Staff Response

The NRC staff agrees with the comment concerning the definition of operability for standard TS.

As noted in the RIS, [o]perational leakage is a safety concern due to the unknown condition of the component when leakage is identified. IMC 0326, section 0 8.13, describes the safety concern as follows:

Unless a 100% through-wall flaw is evaluated and found acceptab le using an applicable methodology [as described in the RIS] and in which a ll provisions are met including any additional requirements or limitations impose d (e.g., by the NRC-approved code case), the system or component does not demon strate structural integrity.

The RIS clarifies operability as follows:

[t]he requirement for maintaining structural integrity is a fun damental assumption used in the development of the TS under Title 10 of the Code of Federal Regulations (10 CFR) 50.36, Technical specifications. TS are derived from safety analyses that assume ASME BPV Code Class 1, 2, and 3 com ponents continue to have structural integrity during operation.

Therefore, an SSC required to be operable by TS that does not d emonstrate structural integrity should be considered inoperable. As stated in comment 2-1, the NRC has established the regulatory requirements for licensees to verify structural inte grity of ASME BPV Code Class 1, 2, and 3 SSCs in 10 CFR 50.55a.

With this understanding, the NRC staff recognizes the comments distinction between ASME BPV Code Class 1 leakage requirements under TS and ASME BPV Cod e Class 2 and 3 system requirements under TS to be operabl e. Some ASME BPV Code Class 2 and 3 components are merely attached to a main system that performs a specified safety function governed by TS, and loss of structural integrity in some such ASME BPV Code Class 2 and 3 components will not necessarily ever challenge the operability of a system governed by TS. While the impact of these leaking ASME BPV Code Class 2 or 3 components, which are not required to be operable by TS, will need to be addressed, the TS would not require a re pair to restore operability.

Repairs on such items would be required in accordance with the owners requirements (e.g., the Technical Requirements Manual) or other corrective action proce ss. This was the purpose of the language in the RIS that qualifies when methods described i n the provisions of the applicable inservice inspection requirements, as specified in 1 0 CFR 50.55a(g), must be used.

The RIS attempts to clarify the entry condition by stating [i] f through-wall operational leakage is observed from an ASME BPV Code Class 1, 2 or 3 SSC and the structural integrity of the SSC must be established to conclude that the system remains ope rable [emphasis added].

The NRC staff recognizes that the language related to the opera bility determination allowance for ASME BPV Code Class 2 and 3 SSCs can be clarified, as inten ded in the RIS. Therefore, the NRC staff will modify the RIS to include additional wording following the second paragraph under the Summary of Issue section of the RIS. This paragraph w ill state the following:

15 To clarify, the language in the preceding paragraph, and the s tructural integrity of the SSC must be established to conclude that the system remains ope rable, is linked to the entry into a TS action statement. Licensees are allowed to eva luate the location to determine if the leakage affects the structural integrity of an SSC governed by TS. If operational leakage is from a component that does not need to m aintain structural integrity for a system to perform its specified safety function, and the leak does not impact the ability of other SSCs, governed by TS, to perform th eir specified safety functions, then the leakage can be addressed through other proc esses (e.g., corrective action program). For example, if the licensee identifies leaka ge from a drain line, the complete failure of which would not affect operability of any s ystem (e.g., complete failure will not result in loss of adequate flow in the main sy stem, will not result in room flooding that could result in loss of a specified safety functi on, etc.), then the requirements discussed in this RIS would not apply. In contras t, any degradation in the main line of a system can challenge the structural integrity of that system and that systems specified safety function. This requires further acti on as identified in this RIS to demonstrate operability. Additionally, for leakage in ASME Cla ss 1 systems, this condition is governed by the leakage allowances of the applicab le TS, and any pressure boundary leakage requires repair of the reactor coolant pressur e boundary, in accordance with this RIS.

This clarification directly addresses the comments example of operational leakage from drains or instrument lines. Note that an assessment of the maximum bou nding leakage must be available to verify that there is no challenge to the safety fu nction of the main safety system from a complete failure of the leaking component. Additionally, the effect of leakage from the complete failure of the component on the possibly affected safe ty systems capability to meet their specified safety function must be assessed.

The other leakage examples presented by the comment do not nece ssarily fall under this clarification. The NRC was not aske d to review for acceptance the Nuclear Energy Institute (NEI) 18-03, Operability Determination (ML19284C872) guidance as noted by the comment.

However, the NRC staff has stated on various occasions that the NRC position on operational leakage is not met by the recommendations of NEI 18-03. Specifi cally, in the case where it is presumed that the ASME BPV Code does not provide a requirement to address operational leakage in an ASME BPV Code Class 2 or 3 SSC, which could impac t the safety function of a system under TS requirements. If an NRC-approved flaw evaluatio n method is not available for the specific component, the ASME BPV Code would require a repai r/replacement activity. The RIS states the following:

Alternatives under 10 CFR 50.55a(z) can be used as long as NRC staff authorization is granted before implementation. Implementation is deemed to be t he moment that the structural integrity of the component is required to be establi shed (e.g., before expiration of the TS allowed completion time ). Licensees can avail themsel ves of the alternative process to propose evaluation methods or repair/replacement act ivities to resolve any circumstances that are not addr essed by NRC-approved ASME Code evaluation methods.

The comment raises additional concerns regarding a perceived fl exibility in using the general allowances of operability determinations provided for a potenti al generic fault in any TS SSC.

The NRC staff notes that other options are available in IMC 032 6; however, the specific section describing the regulatory requirements of 10 CFR 50.55a(g) when addressing operational leakage is in section 08.13 of IMC 0326 for TS SSCs. Section 08.13 is a specific operability

16 issue to address operational leakage in lieu of the general req uirements. See the response to comments 2-1 and 3-2 for further information on this item.

This comment also raises the concern that the relationship betw een operability determinations, corrective actions, and repair/replacement activities of ASME B PV Code Class 2 and 3 SSCs may be confused in the RIS. The comment states that corrective actions and operability are distinct processes. While the NRC staff agrees that these proce sses can be separate, there is no rule that requires them to be separate. Specifically, in the special case of operational leakage, as noted in the RIS, corrective actions may be require d to verify the structural integrity of a TS SSC experiencing operational leakage, and therefore act ions to verify or restore structural integrity (i.e., corrective actions) may need to be completed within a TS-specified timeframe. Additionally, there is no requirement that prevents a licensee from choosing to perform a permanent ASME BPV Code repair to address operational leakage from an ASME BPV Code Class 3 component to verify the structural integrity o f the component. In that case, it would be a corrective action that addresses the continued opera bility of the component. The purpose of the RIS is not to establish rules for operability ge nerically but to clarify the regulatory requirements under 10 CFR 50.55a to verify the structural integ rity of a TS SSC with operational leakage. Current NRC-approved methods include many options and combinations of options (i.e., flaw evaluation, examination expansion, modification, an d repair/replacement), as clarified in the RIS.

The comment also notes that additional activities may be requir ed to address operational leakage. The NRC staff agrees with this position and reiterates that the RIS only provides clarity for the regulatory requirements under 10 CFR 50.55a to verify t he structural integrity of a TS SSC with operational leakage. All other requirements continue t o apply.

The NRC staff will include one additional paragraph in the fina l RIS on operational leakage. This new paragraph was identified in the response to this comment. T his additional paragraph is intended to clarify the current wording in the RIS on operation al leakage.

Comment 3-2

The RISs position that only NRC-approved methods may be used t o determine the operability of an ASME Code Class 2 or 3 SSC exhibiting operational leakage clearly contradicts the agencys own guidance. NRC operability guidance permits the use of alternative methods during the period of corrective action (i.e., methods different than those supporting plant design, including the use of engineering judgement). As stated in Secti on 08.04 of IMC 0326, alternative methods may be useful and acceptable to determine operability if they are technically appropriate for the application. In contrast, the comment notes, a corrective action is the requirement in 10 CFR Part 50, Appendix B, Criterion XVI to res tore a degraded SSC to comply with the design and licensing bases.

NRC Staff Response

The NRC staff disagrees with this comment. Section 08 of IMC 03 26 is entitled Specific Operability Issues. Section 08.04 of IMC 0326 is general guida nce for operability determinations to use alternative methods. However, specific gu idance for operational leakage is contained in section 08.13, Operational Leakage from ASME Class 1, 2 and 3 Components.

IMC 0326 also provides specific guidance for operational leakag e from ASME BPV Code Class 2 and 3 components. The information in section 08.13 of I MC 0326 is consistent with the clarification of options allowed to verify structural integrity, as stated in the RIS. The latest

17 guidance in IMC 0326 has expanded beyond the guidance provided in GL 91-18, Information to Licensees Regarding Two NRC Inspection Manual Sections on Resol ution of Degraded and Nonconforming Conditions and on Operability, dated November 7, 1991 (ML031140549).

However, the regulatory basis of 10 CFR 50.55a, in accordance w ith TS to address operational leakage as a special case, has remained consistent throughout t he various revisions of the NRC inspection manual guidance over the years.

The NRC staff notes that the purpose of the RIS is not to expla in all required operability actions necessary to address leakage but to explain the actions require d to verify the structural integrity of an SSC when operational leakage is identified in order to en sure operability. As noted in the NRC staff response to comment 2-3, licensees may have other rea sons to perform additional assessments when leakage is identified.

The NRC established the requirements of 10 CFR 50.55a(g) to pro vide reasonable assurance of structural integrity for ASME BPV Code Class 1, 2, and 3 SSC s throughout the service life of the plant. The allowance to use Section XI of the ASME BPV Code is a relaxation of the original construction code and license basis for these safety-related SS Cs during the service life of the plant. No provision of 10 CFR 50.36 exempts the licensee from m eeting these requirements.

However, TS do allow licensees time to address a condition to v erify that the SSC can perform its specified safety function. In the case of operational leaka ge, this requires validation of structural integrity, as a fundamental assumption in the develo pment of the TS themselves is to provide reasonable assurance of public health and safety.

No change was made to the RIS in response to the comment.

Comment 6-1

The comment recommends that the NRC should either not allow for another authorized method or should specify the types of alternative methods to address o perational leakage that are authorized. Commentor recommends only allowing for ASME methods or providing stronger guidelines for non-ASME options methods to address operational leakage.

NRC Staff Response

The NRC staff notes that the purpose of the RIS is to clarify t he current regulatory requirements for licensees to address operational leakage in ASME BPV Code C lass 1, 2, or 3 SSCs covered under TS. The RIS listed the options currently available to lic ensees. These methods require performance of a repair/replacement activity in accordance with the original construction code or ASME BPV Code,Section XI, or implementation of an NRC approved substitute for the repair/replacement activity (e.g., Code Case N-513, alternative s under 50.55a(z)) to verify structural integrity. Additionally, the RIS clarifies that lice nsees may use 10 CFR 50.55a(z),

Alternatives to codes and standards requirements, as long as the NRC staff authorization is granted prior to its implementation. Licensees can avail thems elves of the alternatives process to propose evaluation methods or repair/replacement activities to resolve any circumstances that are not addressed by NRC-approved ASME BPV Code evaluation methods. The NRC staff notes that 10 CFR 50.55a(z) is the current regulation that allo ws licensees to seek alternatives from requirements under 10 CFR 50.55a(b)-(h).

No change was made to the RIS in response to the comment.

18