ML12068A233

Requests for Additional Information for the Review of the Grand Gulf Nuclear Station License Renewal Application

ML12068A233
Person / Time
Site:	Grand Gulf
Issue date:	04/04/2012
From:	Ferrer N License Renewal Projects Branch 1
To:	Mike Perito Entergy Operations
Ferrer N
References
TAC ME7493
Download: ML12068A233 (10)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 April 4, 2012 Mr. Michael Peri to Vice President, Site Entergy Operations, Inc.

P.O. Box 756 Port Gibson, MS 39150 SUB~IECT:

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 nathanieLferrer@nrc.gov.

Sincerely, athaniel 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 STATION LICENSE RENEWAL APPLICATION REQUESTS FOR ADDITIONAL INFORMATION SET 2 RAI B.1.19-1 Background. During its audit, the staff reviewed the applicant's program basis document and implementing procedure for the Fatigue Monitoring Program and noted that the program relies on tracking the number of critical thermal and pressure transients to ensure that fatigue usage remains within allowable limits. However, the applicant's implementing procedure discusses a periodic update methodology for manual counting of accrued cycles, determining all relevant plant cycles and computing cumulative usage factors (CUFs). In addition, the implementing procedure discusses partial cycle counting and partial cycle determination (for hydrotests and thermal cycles).

Issue. The Fatigue Monitoring Program uses several different methods for managing cumulative fatigue damage that are not described in LRA Sections B.1.19 and A.1.19 or the applicant's program basis document. Therefore, the details of how the program manages cumulative fatigue damage, including environmental effects when applicable, are not clear. The program's reliance on manual cycle counting, automatic cycle counting, cycle-based fatigue usage updates and partial cycle-based fatigue updates and how they relate to a specific component or fatigue evaluation was not clearly identified. It is also not clear how the different methods work together to ensure that cumulative fatigue damage is managed and the allowable limit is not exceeded (e.g. actual cycles < assumed cycles, CUF < 1.0, CUF < 0.1, CUFen < 1.0).

Request.

a. Describe all of the different methods that are used to manage cumulative fatigue damage with the Fatigue Monitoring Program. Describe any additional methods that are currently planned to be used by the Fatigue Monitoring Program during the period of extended operation to manage cumulative fatigue damage.

b. If a particular method is used for certain components or fatigue evaluations (e.g., design basis, environmentally-assisted, high-energy line break) specifically identify the components/fatigue evaluations that each method relies on. In addition, justify that the particular method is capable of ensuring the analyses remains valid or the allowable limit is not exceeded prior to taking corrective actions.

c. If these monitoring methods are used or will be used in combination with each other; describe how they work together to ensure that cumulative fatigue damage is managed and the allowable limit is not exceeded.

d. Revise the applicable LRA sections, as necessary, (Appendices A and B) to incorporate the details of the different monitoring methods and how the Fatigue Monitoring Program manages cumulative fatigue damage (this includes the use of the FatiguePro software).

If any of the monitoring methods is not a part of the existing program, provide an appropriate enhancement to the program.

ENCLOSURE

- 2 RAI B.1.19-2 Background. The "parameters inspected/monitored" program element of Generic Aging Lessons Learned (GALL) Report AMP X.M1, "Fatigue Monitoring," states that more detailed monitoring of local pressure and thermal conditions may be performed to allow the actual fatigue usage for the specified critical locations to be calculated. LRA Section 8.1.19 states, in part, that the Fatigue Monitoring Program ensures that fatigue usage remains within allowable limits by tracking the number of critical thermal and pressure transients for selected components. In addition, LRA Section 4.3.1.1 states that stress-based fatigue (SBF) monitoring on the feedwater nozzle, the high pressure core spray nozzle, and the feedwater weldolets is being used. LRA Section 4.3.1.2 states the feedwater nozzle fatigue due to plant transients and the rapid cycling fatigue were reanalyzed for EPU operating conditions and will also be reanalyzed to consider the effects of reactor water environment on fatigue.

Issue. Since the Fatigue Monitoring Program relies on tracking the number of transients for selected components to ensure that fatigue usage remains within allowable limits, it is not clear how SBF monitoring is currently incorporated and how it will be used to manage fatigue for the feedwater nozzle, since it will be reanalyzed to consider the effects of reactor water environment.

As discussed in Regulatory Issue Summary (RIS) 2008-30 "Fatigue Analysis of Nuclear Power Plant Components," there were concerns with a methodology that has been used to perform fatigue calculations and as input for on-line fatigue monitoring programs by license renewal applicants or licensees in the current operating term. Specifically, the concern involves an input in which only one value of stress is used for the evaluation of the actual plant transients and that this simplification of the analysis requires a great deal of judgment by the analyst to ensure that the simplification still provides a conservative result.

Request.

a. Since SBF will be used in the reanalysis of the feedwater nozzle to consider the effects of reactor water environment on fatigue, describe and justify any actions that have been or will be taken for the period of extended operation to address the concerns described in RIS 2008-30, related to the use of one value of stress to perform fatigue calculations and as input for on-line fatigue monitoring programs, for any reanalysis that will use SBF.

b. Since SBF monitoring is currently used for the feedwater nozzle, the high pressure core spray nozzle, and the feedwater weldolets, describe and justify the actions that have been taken to ensure that the potential non-conservative methods described in RIS 2008-30 have not challenged the ability to maintain the allowable limit.

RAI B.1.19-3 Background. The "monitoring and trending" program element of GALL Report AMP X.M1 states that trending is assessed to ensure that the fatigue usage factor remains below the design limit during the period of extended operation.

- 3 During its audit, the staff reviewed the implementing procedure for the Fatigue Monitoring Program and noted that it relies on manual cycle counting, cycle-based fatigue usage updates and partial cycle-based fatigue updates. In addition, the staff noted that the applicant uses automatic cycle counting and stress-based fatigue monitoring during the review of the on-site documentation. Furthermore, the staff reviewed the implementing procedures for the Fatigue Monitoring Program, which state that the FatiguePro software computes fatigue usage for critical reactor pressure vessel, piping and piping penetration components.

Issue. During its audit, the staff noted that the implementing procedure only provides direction to generate a condition report that is based on the projected cumulative fatigue usage factor for a component. Since the Fatigue Monitoring Program relies on several different methods of monitoring, it is not clear whether the program includes or will include appropriate trending of the appropriate parameters (e.g. cycles, CUF, CUFen) based on the method of monitoring.

The staff noted that FatiguePro is currently being used and appears that it will continue to be used during the period of extended operation; therefore, it is not clear to the staff why the Updated Final Safety Analysis Report (UFSAR) Supplement update does not contain the details of using FatiguePro to manage cumulative fatigue damage.

Request.

a. For each method used, or that will be used, by Fatigue Monitoring Program, describe and justify the parameter that is or will be trended to ensure that cumulative fatigue damage of metal components caused by anticipated cyclic strains in the material is managed. Discuss the associated action limits for each method of monitoring and justify that there is sufficient margin to ensure that the design limits will not be exceeded. If an enhancement is needed as a result of this RAI, provide the appropriate revisions to the applicable LRA sections (Appendices A and B).

b. Provide the appropriate revisions to the applicable LRA sections (Appendices A and B) to describe the purpose and use of the FatiguePro software for managing cumulative fatigue damage.

RAI8.1.19-4 Background. The "corrective actions" program element of GALL Report AMP X.M1 recommends specific corrective actions if the acceptance criteria are exceeded, in addition to the requirements of 10 CFR Part 50, Appendix B. Specifically, it states acceptable corrective actions include repair of the component, replacement of the component, and a more rigorous analysis of the component to demonstrate that the design code limit will not be exceeded during the period of extended operation. In addition, it recommends program scope expansion to include consideration of other locations with the highest expected cumulative usage factors when considering environmental effects.

-4 The applicant claimed, in its program basis document for the Fatigue Monitoring Program, that the "corrective actions" program element is consistent of GALL Report AMP X.M1.

LRA Section B.1.19 states that the sample set of locations that will address the effects of reactor water environment will include the locations identified in NUREG/CR-6260 and additional plant-specific component locations in the reactor coolant pressure boundary if they are found to be more limiting than those considered in NUREG/CR-6260.

Issue. During its audit, the staff reviewed the "corrective actions" program element in the applicant's program basis document and noted the applicant applies the requirements of 10 CFR Part 50, Appendix B to its program through the Corrective Actions Program. However, the specific recommendations from GALL Report X.M1 for corrective actions that include repair, replacement and reanalysis of the component and scope expansion were not included in the program basis document or Fatigue Monitoring Program.

Since the applicant will be enhancing its program prior to the period of extended operation as described above, it is not clear whether the "corrective actions" program element of the applicant's program will ensure that if any changes/modifications occur in the future that the limiting locations will have been addressed for the effects of reactor water environment.

Request. Justify the claim of consistency with the "corrective actions" program element of GALL Report AMP X.M1, considering the recommendations for corrective actions to include repair, replacement and reanalysis of the component and scope expansion to include other locations when considering environmental effects were not included.

Confirm that the enhanced Fatigue Monitoring Program will continually ensure that the locations managed for effects of reactor water environment will remain limiting for the plant-specific configuration if any plant changes or modifications occur in the future. Alternatively, justify that the program can adequately address the effects of reactor water environment on fatigue life.

RAI8.1.19-5 Background. The "operating experience" program element of GALL Report AMP X.M1 recommends that the program review industry experience relevant to fatigue cracking. The staff noted that RIS 2011-14, "Metal Fatigue Analysis Performed By Computer Software," was issued on December 29,2011. This RIS is associated with the implementation of computer software packages used to demonstrate the ability of nuclear power plant components to withstand the cyclic loads associated with plant transient operations. During its audit, the staff reviewed the implementing procedures for the Fatigue Monitoring Program, which state that the FatiguePro fatigue monitoring software computes fatigue usage for critical reactor pressure vessel, piping and piping penetration components.

Issue. RIS 2011-14 describes concerns regarding the implementation of computer software packages used to demonstrate the ability of nuclear power plant components to withstand the cyclic loads associated with plant transient operations. Specifically, using computer software to compute cumulative usage factors may involve analyst intervention that relies on engineering judgment, which, without control and documentation, could produce results that are not predictable, repeatable, nor conservative.

- 5 During its audit, the staff noted that the applicant uses the computer software, FatiguePro, which performs automatic cycle counting and stress-based fatigue monitoring to manage cumulative fatigue damage of certain components. It is not clear, if the data collected by FatiguePro is reviewed and modified prior to the determination of cumulative fatigue usage for a component or of an accrued transient cycle.

Request.

a. Describe and justify any actions that have been or will be taken to address the concerns described in RIS 2011-14, related to the use of computer software to demonstrate the ability of components to withstand cyclic loads associated with transients and the documentation of analyst's engineering judgment and intervention.

b. Describe the activities that are performed to the information/data that is collected by FatiguePro prior to determining the cumulative fatigue usage for a component or an accrued transient cycle. Further justify if the concerns described in RIS-2011-14, related to documentation of the analyst's engineering judgment and intervention, have been addressed for the current use or will be addressed for the future use of FatiguePro.

8.1.19-6 Background. The "parameters monitored/inspected" program element of GALL Report AMP X.M1 states the program monitors all plant design transients that cause cyclic strains, which are significant contributors to the fatigue usage factor. The implementing procedure for the Fatigue Monitoring Program provides the definition of a "counted cycle" and states that for the definition of "specific system/component cycles, the component stress report should be reviewed." The applicant's procedure continues to describe the basic reactor cycles that contribute significantly to fatigue usage of Class 1 pressure boundary components and is counted in accordance with the procedure.

LRA Section 4.3.1 states that the Fatigue Monitoring Program will ensure that the accrued numbers of cycles of all design transients will remain below the numbers of cycles evaluated in the fatigue analyses.

Issue. It is not clear to the staff, whether the "specific system/component cycles" that are referenced in the applicant's implementing procedures are or will be monitored and tracked by the Fatigue Monitoring Program.

The staff noted that there are several locations which contain information related to design transients and associated design limits:

UFSAR Section 3.9.1.1 provides the design transient for specific components.

UFSAR Table 3.9-1 provides the design transients for the reactor pressure vessel assembly and internals.

• Technical Specification Section 5.5.5 states that the cyclic and transient occurrences identified on UFSAR Table 3.9-35 are tracked to ensure that the reactor vessel is maintained within the design limits. UFSAR Table 3.9-35 also provides limits for four design transients.

- 7 maintained within the design limits. UFSAR Table 3.9-35 also provides limits for four design transients.

LRA Table 4.3-1 provides a list of design transients with the associated projected and analyzed transient cycles.

The staff noted that the number of assumed number of cycles for the same design transient is different, in some instances, between the aforementioned sections for different components.

Request.

a. Confirm that the transient cycles that will be monitored and tracked by the Fatigue Monitoring Program include all transients used in the determination of cumulative usage factors in ASME Class 1 fatigue evaluations and high-energy line break evaluations and will be used in environmentally-assisted fatigue evaluations.

b. If there are any transients used in these calculations that will not be monitored and tracked by the Fatigue Monitoring Program, justify why it is not necessary to monitor these design transients.

c. Confirm that the most limiting cycle limit for a particular design transient, that was or will be used in any fatigue analysis, will be monitored and tracked to assure that action is taken prior to any applicable fatigue analysis becoming invalid. If different cycle limits are applicable to specific design transients or components, describe and justify how the Fatigue Monitoring Program will "assure that action is taken if the actual cycles approach their analyzed numbers" and the applicable fatigue analysis will not be invalid.

Background. LRA Section B.1.19 provides an enhancement to the "detection of aging effects" program element, which states the program will be enhanced to revise program documents to provide updates of the fatigue usage calculations on an as-needed basis if an allowable cycle limit is approached, or in a case where a transient definition has been changed, unanticipated new thermal events are discovered, or the geometry of components has been modified.

The "detection of aging effects" program element of GALL Report AMP X.M1 states the program provides for updates of the fatigue usage calculations on an as-needed basis if an allowable cycle limit is approached, or in a case where a transient definition has been changed, unanticipated new thermal events are discovered, or the geometry of components have been modified.

Issue. During its audit, the staff reviewed the applicant's implementing procedures for the Fatigue Monitoring Program and noted that the relation between the different monitoring methods (e.g. cycle counting, cycle-based fatigue and stressed based fatigue) is not apparent.

Therefore, it is not clear to the staff what aspects of the program and procedures will be revised to account for this enhancement.

In addition, the enhancement is specific about updates to calculations when an allowable cycle limit is approached; however, since the program relies on different monitoring methods, it is also

-7 not clear if and when updates to calculations will be required for other parameters (e.g. actual cycles < assumed cycles, CUF < 1.0, CUF < 0.1, CUFen < 1.0) that are monitored.

Request. Provide a description of how the implementing procedures for the Fatigue Monitoring Program will be revised to implement this enhancement. considering that the program relies on several monitoring methods (i.e., manual and automatic cycle counting. cycle-based and partial cycle-based fatigue monitoring and stress-based fatigue monitoring).

SUBJECT:

REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE GRAND GULF NUCLEAR STATION, LICENSE RENEWAL APPLICATION DISTRIBUTION:

HARD COPY:

DLR RF E-MAIL:

PUBLIC [or NON-PUBLIC, if applicable]

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Mr. Michael Perito Vice President, Site Entergy Operations, Inc.

P.O. Box 756 Port Gibson, MS 39150

SUBJECT:

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, 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.:ML12068a233 PM:RPB1 :DLR BC:RPB1 :DLR PM:RPB1 :DLR OFFICE LA: RPB1 :DLR DMorey NFerrer NFerrer NAME YEdmonds 3/28/12 3/23/12 3/27/12 DATE OFFICIAL RECORD COpy