ML12312A453

RAI for the Review of the Grand Gulf Nuclear Station License Renewal Application

ML12312A453
Person / Time
Site:	Grand Gulf
Issue date:	11/20/2012
From:	Ferrer N B License Renewal Projects Branch 1
To:	Mike Perito Entergy Operations
Ferrer N B, 415-1045
References
TAC ME7493
Download: ML12312A453 (8)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 November 20,2012 Mr. Michael Perito Vice President, Site Entergy Operations, Inc. P. O. Box 756 Port Gibson, MS 39150 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE GRAND GULF NUCLEAR STATION LICENSE RENEWAL APPLICATION (TAC NO. ME7493) Dear Mr. Perito: By letter dated October 28, 2011, Entergy Operations, Inc., submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54, to renew the operating license for Grand Gulf Nuclear Station, Unit 1 (GGNS) for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review. These requests for additional information were discussed with Jeff Seiter, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-1045 or e-mail nathaniel.ferrer@nrc.gov. Sincerely, Nathaniel Ferrer, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-416 Enclosure: Requests for Additional Information cc w/encl: Listserv GRAND GULF NUCLEAR LICENSE RENEWAL REQUESTS FOR ADDITIONAL INFORMATION SET RAI 4.2.1-2b Background. In its License Renewal Application, the applicant used a reactor vessel fluence estimate that was obtained by combining a pre-extended power uprate (EPU) fluence value obtained from MPM Technologies calculations to a post-EPU f1uence value obtained from General Electric Hitachi (GEH). By letter dated October 15, 2012, the applicant responded to RAI 4.2.1-2a that, in part, addressed the discrepancies between the pre-EPU and post-EPU flux values for the core shroud welds (H1, V1, V2, V3, and V4 welds in the top portion of the core shroud). In the applicanfs analysis for these weld locations, the pre-EPU peak flux values are greater than the post-EPU peak flux values approximately by three orders of magnitude (i.e., approximately 1.0E10 n/cm2-s versus 1.0E07 n/cm2-s). The core shroud neutron flux values are described in the applicanfs response, dated July 25, 2012, to RAI 4.2.1-2. In addition, RAI4.2.1-2a addressed the issue regarding the combined analytic uncertainty associated with the two different methods for the pre-EPU and post-EPU fluence calculations (i.e., MPM method and GEH method, respectively). Issue. The applicanfs response to RAI 4.3.1-2a states that the MPM approach used a bounding-case flux at the core shroud weld locations in the top portion of the core shroud shell. However, the applicanfs response does not provide specific information to justify why the flux values obtained from the MPM method are bounding-case flux values for the core shroud weld locations. In addition, the applicanfs response indicates the following with respect to the combined analytic uncertainty: The applicant acknowledged that proving the independence of all uncertainty terms in both fluence calculations is not possible. The applicant stated that because the independence of the uncertainty values cannot be proven, relative uncertainties are considered instead. The applicant expressed total uncertainty as a "relative uncertaintY' combination, which is, in actuality, a weighted average of the uncertainties associated with both methods. The staff noted the following issues with the applicanfs response: The applicanfs approach is not a valid or acceptable way to perform an analytic uncertainty analysis because it is not consistent with Regulatory Guide (RG) 1.190. The errors associated with both f1uence calculation methods will propagate when the two fluence calculational methods are combined. ENCLOSURE

-2 The uncertainty associated with adding the two fluence values together should be higher than either as a stand-alone calculation. Request. Provide additional information to clarify why the flux values obtained from the MPM method are bounding-case flux values for the core shroud weld locations (Le., H1, V1, V2, V3, and V4 welds). As part of the response, clarify which locations are actually associated with the bounding-case flux values and why the bounding-case flux values have sufficient conservatisms as bounding-case values. Provide an analytic uncertainty analysis for the combined fluence values, consistent with RG 1.190 that states that each of the fluence methods be supported by an analytic uncertainty analysis. Alternatively, provide reactor vessel neutron fluence values that were calculated using a single, NRC-approved method that has a valid and accepted analytic uncertainty analysis, and reconfirm the validity of the related neutron embrittlement time-limited aging analysis (TLAAs) in light of the updated fluence values. RAI4.7.3-1a Background. In its response to RAI4.7.3-1 dated July 25,2012, as revised by letter dated September 4, 2012, the applicant provided a list of components included in the TLAA of reactor vessel internals fluence effects. The applicant also provided the 40-and 60-year fluence values for these components and indicated that these values were calculated in accordance with General Electric Licensing Topical Report NEDC-32983P-A, "General Electric Methodology for Reactor Pressure Vessel Fast Neutron Flux Evaluations;' Revision 2 (GE methodology). Issue. Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants (SRP-LR) Section 4.7.3.1.2 states that, for TLAA dispositions pursuant to 10 CFR 54.21 (c)(1 )(ii), the applicant shall provide a sufficient description of the re-analysis and document the results to show that it is satisfactory for the 60-year period. In RAI4.7.3-1, the staff requested the applicant to identify the applicable design requirements to show that the results of the re-analysis meet those requirements. The applicant did not provide this information; therefore, the applicant has not shown that the results of the re-analysis are satisfactory for 60 years. SRP-LR Section 4.7.3.1.2 also states that the applicable analysis technique can be the one that is in effect in the planfs current licensing basis (CLB) at the time when the license renewal application is filed. The response to RAI4.7.3-1 states that the GE methodology was used to calculate the 60-year f1uence values for the reactor vessel internals. This 60-year period includes pre-EPU fluence and post-EPU f1uence through the period of extended operation. The response to RAI 4.2.1-2 states that the GE methodology was incorporated into the CLB during EPU license amendment approval, which occurred after the license renewal application was filed. As such, it is not clear whether use of the GE methodology for calculating pre-EPU fluence values was consistent with the CLB.

-3 The response to RAI4.7.3-1 states that non-core support structure components (Le., jet pump beam bolt and shroud head studs) were evaluated in the TLAA of reactor vessel internals f1uence effects; however, the updated final safety analysis report (UFSAR) supplement summary description of the TLAA in LRA Section A.2.5.3 does not address the analysis of these components. Request. Provide the applicable design requirements for each component included in the TLAA (e.g., f1uence values, bolting preload values). Show that these requirements are met as a result of the re-analysis of fluence effects through the proposed 60 years of plant operation. Justify use of the GE methodology for calculating f1uence for the reactor vessel internals pre-EPU. RAI 8.1.22-1 b Background. The GGNS response dated October 2, 2012, to RAI B.1.22-1 a acknowledged that its Flow-Accelerated Corrosion Program manages loss of material due to mechanisms other than flow-accelerated corrosion, and revised a number of tables in the LRA to include a line item that credits the Flow-Accelerated Corrosion Program for managing the loss of material of carbon steel piping in treated water. The revised tables include GALL Report item V.D2.E-09, which correlates to SRP-LR item 3.2.1-11, for steel components exposed to steam or treated water that are being managed for wall thinning due to flow-accelerated corrosion. In addition, GGNS revised LRA Section A.1.22 and provided an exception in Section B.1.22, by noting in the "scope of program" program element, that the Flow-Accelerated Corrosion Program also addresses loss of material due to erosion mechanisms. Issue. The aging management review (AMR) item added to the various tables is specific to wall thinning due to flow-accelerated corrosion; however, the associated components are being managed for loss of material due to erosion mechanisms that are not flow-accelerated corrosion. In that regard, neither the GALL Report nor the SRP-LR currently contain any AMR items to address wall thinning due to erosion mechanisms in piping, piping components or piping elements. Although component degradation due to erosion mechanisms can be managed through the Flow-Accelerated Corrosion Program, it is important that the program distinguish between the components being managed for the different mechanisms. Component degradation due to flow-accelerated corrosion can be addressed by replacements with "FAC [flow-accelerated corrosionj-resistant" material; however, "high-chromium materials do not protect against other damage mechanisms, such as cavitation and liquid impingement erosion," as stated in NSAC-202L, Section 4.2.2. In addition, the exception cited in the RAI response does not address all of the differences that may need to be incorporated into the Flow-Accelerated Corrosion Program. As discussed above, "FAC-resistant" materials will not resolve degradation due to erosion, which needs to be addressed in the "corrective actions" program element. Also, since the component susceptibility may not be predicted using the existing modeling, the "detection of aging effects" may need to account for the extent of condition process that was used to identify other susceptible Finally, the "monitoring and trending' program element may need to account for specific usage components that are not in constant Request. Provide additional bases to justify the exception to the Flow-Accelerated Program by addressing any needed changes to the 10 aging management program In addition, provide additional detail in the LRA tables such that the AMR item associated with the erosion aging mechanism are RAI B.1.41-3b Background. Based on information in GGNS condition report CR-GGN-2010-01344, regarding loss of material due to erosion/corrosion in the standby service water system, the staff requested additional information regarding GGNS-MS-46, "Program Plan for Monitoring Internal Erosion/Corrosion in Moderate Energy Piping Components:' The response to RAJ B.1.41-3, dated May 25,2012, states that procedure MS-46 is not "credited to manage the effects of aging for components that are included in the Service Water Integrity Program:' However, the response to RAI B.1.41-3a, dated October 2,2012, states that GGNS-MS-46 provides instructions for implementing the inspection of components subject to aging management review, and that "[t]hese inspections are ongoing monitoring activities that are credited by aging management programs described in the GGNS LRA, such as the Fire Water System Program, the Water Chemistry Control-Closed Treated Water Systems Program, and the Service Water Integrity Program:' Issue. It is not clear which, if any, components within the scope of license renewal are being managed for loss of material due to erosion/corrosion through the ongoing monitoring activities of GGNS-MS-46. The staff noted that there are no items in the LRA being managed for loss of material due to erosion/corrosion, despite the fact that the recent RAI response states that the inspections prescribed in MS-46 are "ongoing monitoring activities that are credited by [several] aging management programs:' If specific components are being monitored due to identified degradation caused by erosion/corrosion, then these aging management activities should have resulted in an AMR item for each system where the ongoing monitoring activities in GGNS-MS-46 are occurring. It is not clear whether the three aging management programs (AMPs) citied above, for which GGNS-MS-46 provides inspection instructions, manage loss of material due to erosion/corrosion. The LRA states that these programs are consistent with the GALL Report AMPs, and none of the GALL Report AMPs manage loss of material due to erosion/corrosion. Although the GALL Report AMP for the Open Cycle Cooling Water System addresses loss of material due to erosion, this is only associated solid particle erosion and does not include other erosion mechanisms that may be included with erosion/corrosion. In addition, GGNS-EP-OB-LRD06, "Aging Management Program Evaluation Report Non-Class 1 Mechanical;' which was provided to the staff during staffs onsite AMP audit, does not cite MS-46 as an implementing procedure for the three AMPs cited in the response above. Consequently, the requirements of 10 CFR 54.37(a) may not be met for auditable records to document the compliance with the provisions of Part 54.

-Request. Provide additional detail in the LRA tables such that the AMR items associated with the erosion aging mechanism are identified. Update the AMP descriptions in LRA Sections A and B to reflect the aging management of erosion/corrosion, as necessary. Confirm that the Service Water Integrity Program does not include any other activities beyond those described in the GGNS Response to GL 89-13, if appropriate. Also, confirm that the appropriate sections of GGNS-EP-08-LRD06, "Aging Management Program Evaluation Report Non-Class 1 Mechanical;' will be updated to include GGNS-MS-46 for the applicable AMP where associated ongoing monitoring activities are currently credited. Otherwise, provide the basis for why GGNS-EP-08-LRD06 does not need to be updated. Provide a summary of recent inspection activities performed through GGNS-MS-46.

November 20,2012 Mr. Michael Perito Vice President, Site Entergy Operations, Inc. P. O. Box 756 Port Gibson, MS 39150 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE GRAND GULF NUCLEAR STATION LICENSE RENEWAL APPLICATION (TAC NO. ME7493) Dear Mr. Perito: By letter dated October 28, 2011, Entergy Operations, Inc., submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54, to renew the operating license for Grand Gulf Nuclear Station, Unit 1 (GGNS) for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review. These requests for additional information were discussed with Jeff Seiter, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-1045 ore-mail nathaniel.ferrer@nrc.gov. Sincerely, IRA! Nathaniel Ferrer, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-416 Enclosure: Requests for Additional Information cc w/encl: Listserv DISTRIBUTION: See following pages ADAMS Accession No'.. ML 12312A453 *concurred via email IOFFICE LA:RPB1 :DLR* PM:RPB1 :DLR BC:RPB1 :DLR PM: RPB1:DLR NAME YEdmonds NFerrer DMorey NFerrer DATE 11/15/12 11/14/12 11/19/12 11/20/12 OFFICIAL RECORD COpy Letter to M. Peri to from N. Ferrer dated November 20,2012 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE GRAND GULF NUCLEAR STATION, LICENSE RENEWAL APPLICATION DISTRIBUTION: HARDCOPY: DLR RF E-MAIL: PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRpb2 Resource RidsNrrDlrRarb Resource RidsNrrDlrRapb Resource RidsNrrDlrRasb Resource RidsNrrDlrRerb Resource RidsNrrDlrRpob Resource NFerrer DDrucker DWrona DMorey AWang RSmith, RIV BRice, RIV GPick, RIV DMclntyre, OPA