South Texas Project, Units 1 and 2 - Supplemental …

Nuclear Operating Company

South Texas Pro/ectElectric GeneratingStation PO.Box 289 Wadsworth, Texas 77483

? A AA?

March 29, 2012 NOC-AE- 12002825 10 CFR 54 STI: 33417770 File: G25

U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

South Texas Project Units 1 and 2

Docket Nos. STN 50-498, STN 50-499 Supplemental Response to Requests for Additional Information for the

South Texas Project License Renewal Application Agingq Management Program, Set 13 and Set 14 (TAC Nos. ME4936 and ME4937)

References: 1. STPNOC letter dated October 25, 2010, from G. T. Powell to NRC Document Control Desk, "License Renewal Application" (NOC-AE-10002607) (ML1 03010257)

2. NRC letter dated February 15, 2012, "Requests for Additional Information for the Review of the South Texas Project, Units 1 and 2, License Renewal Application -Aging Management, Set 13 (TAC Nos. ME4936 and ME 4937)" (ML12039A240)

3. STPNOC letter dated March 12, 2012, from G. T. Powell to NRC Document Control Desk "Response to Requests for Additional Information for the South Texas Project License Renewal Application - Aging Management Program, Set 13 (TAC Nos. ME4936 and ME4937)" (NOC-AE-12002802) (ML12079A015)

4. NRC letter dated February 28, 2012, "Requests for Additional Information for the Review of the South Texas Project, Units 1 and 2 License Renewal Application Aging Management, Set 14 (TAC Nos. ME4936 and ME 4937)"(ML12053A430)

5. STPNOC letter dated March 28, 2012, from D. W. Rencurrel to NRC document Control Desk "Response to Requests for Additional Information for the South Texas Project License Renewal Application Aging Management Program, Set 14 (TAC Nos. ME4936 and ME4937)" (NOC-AE-12002811)

By Reference 1, STP Nuclear Operating Company (STPNOC) submitted a License Renewal Application (LRA) for South Texas Project (STP) Units 1 and 2. By Reference 2 and 4, the NRC staff requested additional information for review of the STP LRA. STPNOC provided responses to the requests for additional information in References 3 and 5. Additional responses to References 2 and 4 are provided in Enclosure 1 to this letter. Changes to LRA pages described in Enclosure 1 are depicted as line-in/line-out pages provided in Enclosure 2.

One revised regulatory commitment is provided in Enclosure 3. There are no other regulatory commitments provided in this letter.

A14q

NOC-AE-12002825 Page 2

Should you have any questions regarding this letter, please contact either Arden Aldridge, STP License Renewal Project Lead, at (361) 972-8243 or Ken Taplett, STP License Renewal Project regulatory point-of-contact, at (361) 972-8416.

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

Executed on

!2.( I

Date

KJT Enclosure:

Wencurrel chief Nuclear Officer

1. STPNOC Supplemental Response to Requests for Additional Information 2. STPNOC LRA Changes with Line-in/Line-out Annotations 3. Regulatory Commitments

cc:

(paper copy)

Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, Texas 76011-4511

Balwant K. Singal Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (MS 8B1) 11555 Rockville Pike Rockville, MD 20852

Senior Resident Inspector U. S. Nuclear Regulatory Commission P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483

C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704

John W. Daily License Renewal Project Manager (Safety) U.S. Nuclear Regulatory Commission One White Flint North (MS 011-F1) Washington, DC 20555-0001

Tam Tran License Renewal Project Manager (Environmental) U. S. Nuclear Regulatory Commission One White Flint North (MS O11F01) Washington, DC 20555-0001

NOC-AE-12002825 Page 3

(electronic copy)

A. H. Gutterman, Esquire Kathryn M. Sutton, Esquire Morgan, Lewis & Bockius, LLP

John Ragan Chris O'Hara Jim von Suskil NRG South Texas LP

Kevin Polio Richard Pena City Public Service

Peter Nemeth Crain Caton & James, P.C.

C. Mele City of Austin

Richard A. Ratliff Alice Rogers Texas Department of State Health Services

Balwant K. Singal John W. Daily Tam Tran U. S. Nuclear Regulatory Commission

Enclosure 1 NOC-AE-12002825

Enclosure I STPNOC Response to Requests for Additional Information

Enclosure 1 NOC-AE-12002825

Page 1 of 8

STPNOC Supplemental Response to Requests for Additional Information

SOUTH TEXAS PROJECT, UNITS I AND 2 REQUEST FOR ADDITIONAL INFORMATION -

AGING MANAGEMENT, SET 13 (TAC NOS. ME4936 AND ME4937)

STP TLAA Exemptions (058) (References 2 & 3)

RAI 4.1-2a

Background:

In RAI 4.1-2 the staff asked the applicant to clarify which edition of the American Society of Mechanical Engineers (ASME) Code Section was applicable to the design of the containment liners, and to clarify whether the design code of record for the liners required a metal fatigue analysis. In the applicant's response to RAI 4.1-2 (November 21, 2011), the applicant provided its basis on why a fatigue analysis was not needed to be performed for the containment liners, based on their ASME Section III, Division 2 design code. The applicant stated that this design code did not require the liners to be analyzed to ASME III NE-3000 requirements, and therefore that the current licensing basis (CLB) did not include a fatigue analysis for the containment liners.

Issue:

The staff has confirmed the accuracy of the information in the applicant's response to RAI 4.1-2 through an audit of the applicant's design specification for the STP containment liner, penetrations, airlocks, and equipment hatches. However the design specification states that the "requirements for an 'analysis of cyclical loading' will be investigated in accordance with Section NE-3222.4 and NE-3121 ... of the ASME Code Section II1." Thus, the staff needs further clarification on whether the fatigue analysis statement in the design specification was only applicable to those containment components designed to ASME Code Section III, Division 1 requirements (e.g., the containment penetrations) or whether the fatigue analysis statement in the design specification is also applicable to the containment liners that were designed to ASME Code Section III, Division 2 requirements.

Request:

Clarify whether the fatigue analysis statement in the containment liner design specification is only applicable to those components in the specification that were designed to ASME Code Section III, Division 1 requirements (e.g., the containment penetrations) or whether the fatigue analysis statement is also applicable to the containment liners as well, which were designed to ASME Code Section III, Division 2 requirements.

Enclosure 1 NOC-AE-12002825

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If the fatigue analysis statement in the design specification is applicable to the containment liners, clarify whether the liners would have been required to be analyzed for a fatigue analysis in accordance with the ASME Section III NE-3222.4 and NE-3121 code paragraphs, or else, provide clarification on whether the liners were exempted from a fatigue analysis in accordance with the fatigue waiver provision in NE-3222.4(d). If the NE-3222.4 code provisions are applicable to containment liners, provide your justification on why the fatigue analysis or fatigue waiver analysis (whichever is applicable to the liners) would not need to be identified as a TLAA, when compared to the six criteria for TLAAs in 10 CFR 54.3.

STPNOC Response:

The code jurisdiction for the design of the concrete containment and steel liner is clarified in the STP Design Criteria for the containment building (Section 3.2, "Code Jurisdiction", of Design Criteria SQ-1005, Revision 3, "Reactor Containment Building"), which says:

A. The prestressed concrete shell and dome, together with the reinforced concrete mat forming the pressure boundary, shall be designed in accordance with the ASME Code, Section III, Division 2.

B. The carbon steel liner plate, together with the brackets supporting the polar crane runway girders and rail accessories, shall be designed according to the ASME Code, Section III, Division 2.

C. The equipment hatch, personnel airlock, and auxiliary personnel airlock, together with all mechanical and electrical penetration sleeves, are classified as ASME Section III, Division 1, Class MC components.

Consistent with the above, the liner design specification reviewed by the NRC staff states in Section 1.1.2.3.2 of the specification that the liner "shall serve as a leak-tight membrane (but not as a pressure vessel)".

Paragraph CC-3760 ("Fatigue") of ASME Section III, Division 2 (ASME-ACI 359) states:

In general, the design of metallic liners is not fatigue controlled, since most stress and strain changes will occur only a small number of times and/or produce only minor stress-strain fluctuations. ... Nevertheless, because of the critical nature of the metallic liner, the designer shall ensure the suitability of the metallic liner for the specific operating conditions involving cyclic application of loads and thermal conditions that have been establishedin the Design Specification. The fatigue methods and limits established by Section III, Division 1 shall apply. [Italics added]

STP concludes that the fatigue analysis requirement in paragraph CC-3760 is applicable only to the portions of the liner designated in the design specification as critical pressure-retaining class MC elements, i.e. the openings and penetrations because:

Enclosure 1 NOC-AE-12002825

Page 3 of 8

* The Code refers back to the Design Specification;

? The Code states that the fatigue analysis is required because of the critical nature of the metallic liner; and

" The Code specifically requires use of Division 1 methods for performing fatigue analysis.

Accordingly, there is no fatigue analysis of the metallic liner, other than at openings and penetrations.

A review of the containment liner plate design report verifies that ASME Section III NE-3222.4 and NE-3121 are not applicable to the containment liner. Therefore, there is no associated TLAA.

RAI 4.1-3a

Backgqround:

In the applicant's response to RAI 4.1-3 (November 21, 2011), the applicant indicated that the design basis information in the Updated Final Safety Analysis Report (UFSAR) Section 5.2.3.3.2 provides the applicant's design basis for addressing underclad cracking in the reactor vessel nozzles made from SA-508, Class 2 forging materials. The applicant also stated that the referenced "special evaluation" UFSAR Section 5.3.1.2 does not need to be identified as a TLAA because the regulatory position in NRC RG 1.43 for qualifying clad-to-forging weld qualification tests do not account for an aging mechanism or involve a time-dependent aging parameter. The staff's original request for additional information (RAI) 4.1-3 provides a more detailed background and summary of the staffs initial concern regarding this issue.

Issue:

In its response to RAI 4.1-3, the applicant based its "absence of a TLAA" conclusion for the RV SA-508 Class 2 forging components on the criteria that were established in RG 1.43 and not on the activities or analyses that were implemented in the CLB in order to conform to the weld qualification test criteria in RG 1.43. Nor was the applicant's conclusion based on a comparison of these activities or evaluations to the criteria for identifying TLAAs in 10 CFR 54.3.

Request:

Summarize and describe in sufficient detail the type of tests or evaluations that were performed as part of the CLB in order to meet the recommended weld qualification criteria RG 1.43. If an analysis, evaluation, or calculation was performed as part of the CLB for STP's weld qualification basis, clarify how the applicable document of record compares to each of the six (6) criteria for TLAAs in 10 CFR 54.3, and identify whether

Enclosure 1 NOC-AE-12002825

Page 4 of 8

the analysis, evaluation or calculation needs to be identified as a TLAA in accordance with 10 CFR 54.21(c)(1). Justify the basis for your determinations and conclusions.

STPNOC Response:

STP reevaluated the issue of intergranular separation in the heat-affected zone of reactor vessel low-alloy steel under austenitic stainless steel (SS) cladding as a potential TLAA and conservatively dispositioned this as a TLAA in accordance with 10 CFR 54.21 (c)(1)(i). WCAP-1 5338-A, A Review of CrackingAssociated with Weld Deposited Claddingin OperatingPWR Plants,documents that underclad cracking does not represent a challenge to reactor vessel integrity for an operating term of 60 years. WCAP-1 5338-A concludes that in the presence of underclad cracks, the maximum expected flaw predicted by the crack growth analysis is less than the ASME Section Xl allowable flaw size. WCAP-15338-A uses 1.5 times the numbers of cyclic and transient loads assumed for the original 40-year life which bounds the numbers of cycles projected over 60 years. The cyclic and transient loads used in WCAP-1 5338-A bound those expected in the STP pressure vessels for the 60-year life as shown in LRA Table 4.3-2 This TLAA is dispositioned in accordance with 10 CFR 54.21(c)(1)(i).

LRA Section 3.1.2.2.5, Section 4.7.4, Table 4.1-1 and Table 4.1-2 are revised, and LRA Appendix A3.6.5 is added to disposition intergranular separation in the heat-affected zone (HAZ) of reactor vessel low-alloy steel under austenitic SS cladding as a TLAA in accordance with 10 CFR 54.21(c)(1)(i).

Enclosure 2 provides the line-in/line-out revision for changes to LRA Sections 3.1.2.2.5 and 4.7.4 and to Tables 4.1-1 and 4.1-2. Enclosure 2 also provides the lined-in new LRA Appendix A3.6.5.

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