ML13240A320

Revise the Reactor Pressure Vessel Material Surveillance Capsule Withdrawal Schedule Due to License Renewal Amendment (TAC Nos. MF0631 and MF0632)

ML13240A320
Person / Time
Site:	Sequoyah
Issue date:	09/27/2013
From:	Siva Lingam Plant Licensing Branch II
To:	James Shea Tennessee Valley Authority
Lingam S
References
TAC MF0631, TAC MF0632
Download: ML13240A320 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 27, 2013 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

SEOUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - REVISE THE REACTOR PRESSURE VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE DUE TO LICENSE RENEWAL AMENDMENT (TAC NOS. MF0631 AND MF0632)

Dear Mr. Shea:

By letter dated January 10, 2013, and supplemented by letter dated July 3, 2013, Tennessee Valley Authority submitted a revised reactor pressure vessel (RPV) material surveillance specimen withdrawal schedule for Sequoyah Nuclear Plant (SON), Units 1 and 2. The revised schedule will support license renewal of the SON, Units 1 and 2 operational licenses for an additional 20 years.

The NRC staff has completed its review of the revised RPV surveillance capsule withdrawal schedule and concludes that, given the relocation of Capsules Sand W occurs during the 19th or 20th refueling outages, the revised withdrawal dates of end of cycle (EOC) 28 for Unit 1 and EOC 27 for Unit 2, for surveillance capsule S at SON, are acceptable. The revised schedule will meet the expectations of American Society for Testing and Materials E 185-82, NUREG-1801 ,

Revision 2, "Generic Aging Lessons Learned (GALL) Report," and the requirements of Title 10 of the Code of Federal Regulations, Part 50, Appendix H.

Sincerely,

~(f.~

Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosure:

Safety Evaluation cc w/encl: Distribution via ListServ

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION OF THE REVISED REACTOR PRESSURE VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE TENNESSEE VALLEY AUTHORITY SEOUOYAH NUCLEAR PLANT. UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328

1.0 INTRODUCTION

By letter dated January 10, 2013, (Reference 1), as supplemented by letter dated July 3,2013 (Reference 2), Tennessee Valley Authority (TVA or the licensee) submitted a request to the U.S. Nuclear Regulatory Commission (NRC) to revise the withdrawal date for reactor pressure vessel (RPV) surveillance capsules for Sequoyah Nuclear Plant (SON). Units 1 and 2. The purpose of the licensee's submittal was to obtain NRC approval of a revision to the RPV surveillance specimen withdrawal schedules for the two units at SON. The revised schedules will support license renewal of the SON, Units 1 and 2 operational licenses for an additional 20 years.

2.0 REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix H, "Reactor Vessel Material Surveillance Program Requirements," requires licensees to monitor changes in the fracture toughness properties of ferritic materials in the RPV beltline region of light water nuclear power reactors, which result from exposure of these materials to neutron irradiation and the thermal environment. Appendix H states, "The design of the surveillance program and the withdrawal schedule must meet the requirements of the edition of ASTM [American Society for Testing and Materials] E185 that is current on the issue date of the ASME [American Society of Mechanical Engineers] Boiler and Pressure Vessel Code to which the reactor vessel was purchased. Later editions of ASTM E185 may be used, but including only those editions through 1982." The applicable edition of ASTM E185 for SON, Units 1 and 2 is ASTM E185-82, "Standard Practice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels." Additionally, Appendix H requires that the licensee submit the ASTM E185 compliant schedules to the NRC for staff approval.

The licensee's RPV material surveillance program for the current operating license, which will expire on September 7,2020, for Unit 1 and September 15, 2021, for Unit 2, conforms to ASTM E185-82. ASTM E185-82 recommends that sets of specimens be removed at three or more separate times. As summarized in the Updated Final Safety Analysis Report (UFSAR) and the current submittal, four capsules were used in the existing withdrawal plan; an additional four Enclosure

-2 standby capsules are located in lower fluence regions around the core. The final capsule associated with the current surveillance program at each unit was Surveillance Capsule Y; Capsule Y was removed at 10.03 effective full power years (EFPY) for Unit 1 and at 10.54 EFPY for Unit 2.

The most recent change to the surveillance program for each unit (described in Enclosure 2 to Reference 1) involves relocating two of the standby surveillance capsules (Capsules Sand W) from the low fluence regions to higher fluence locations in each unit's RPV. The move would take place at the end of cycle (EOC) 19 or 20 at each unit. The objective of this relocation is to have meaningful data for license renewal and possible subsequent license renewal. The capsule relocation satisfies the criteria for changes under 10 CFR 50.59(c)(1) so that NRC approval for moving the capsules from the low-fluence region to the position with a higher lead factor is not required. To be consistent with NUREG-1801, Revision 2 (the Generic Aging Lessons Learned (GALL) report, Reference 3), the surveillance program must be revised for license renewal so that a capsule will be withdrawn at a neutron fluence level exceeding, but not greater than twice, the peak RPV neutron fluence at 60 years of operation (52 EFPY for SON). This guidance is also consistent with an extrapolation of ASTM E185-82 for the extended license period. The license renewal application (Reference 4) for SON, Units 1 and 2 is currently under NRC staff review.

3.0 TECHNICAL EVALUATION

In the process of reviewing the request, the NRC staff determined that additional information was needed to complete the evaluation. The ASTM E185-82 standard practice describes the withdrawal schedule in terms of either a target fluence for the capsule or the EFPY of the RPV, whichever comes first. The licensee's submittal is written in terms of EFPY without the target fluence for the capsule. In request for additional information (RAI) 1, the NRC staff asked the licensee to describe the withdrawal schedule (Tables 1 through 4) in terms of the fast neutron fluence (E>1 million electron volts (MeV)) in addition to the EFPY.

Bya letter dated July 3, 2013, TVA provided revisions to Tables 2 through 4 so that the equivalent fast neutron fluence (E>1 MeV) is shown in addition to the plant-specific EFPY values. The licensee points out that Table 1 is a direct copy from the UFSAR and does not need to be updated.

The NRC staff has reviewed the revised tables and notes that the information in Table 1 (not revised as part of this RAI response) is included in the revision to Table 4. The NRC staff finds the response acceptable because the information in the revisions to Tables 2 through 4 is adequate to allow the staff to make a regulatory decision. This resolves the issue raised in RAI 1.

In the second RAI, the NRC staff asked the licensee to provide a list of all materials included in Capsule S and state if the contents of all the remaining capsules are the same. Furthermore, the NRC staff asked if any other pressurized-water reactor sister plants would use the results from the SON program. In the letter dated July 3,2013, the licensee reproduced the tables from the original WCAP reports (References 5 and 6) where the number and type of specimens included in each capsule for the two units is described. In addition, the licensee clarified that there are no other pressurized-water reactors that would use the results from the SON program. The NRC staff finds the information in the response to RAI 2 acceptable because it clarifies the details regarding the contents of each capsule, resolving the issue raised in RAI2.

-3 For the third RAI, the NRC staff requested technical justification for why the fluence values of the withdrawn capsules reported in Table 4 of the January 10, 2013, submittal are different from those described in the previous capsule analysis reports such as WCAP-15224, Revision 0 and WCAP-15320, Revision 0 (References 7 and 8).

In the letter dated July 3, 2013, the licensee summarized the differences as follows. The previous capsule analysis reports were based on the guidance from Draft Regulatory Guide DG-1053, and included a less detailed 1~ux synthesis approach. The methodology used in the 2012 analysis (Reference 9) reported in Table 4 of the January 10, 2013, submittal is based on a more detailed approach that is described in Equation 4 of Regulatory Guide (RG) 1.190. This methodology has been approved by the NRC staff in WCAP-16083-NP-A (Reference 10). The updated, NRC-approved methodology removes three conservatisms from the analysis and, also, used more cycles of actual reactor performance to project the end of life fluence rather than estimates.

The NRC staff has reviewed the response and finds the information to be an adequate summary of the steps taken by the licensee to estimate the neutron fluence at the inside surface of the RPV.

Given the explanation in the RAI response, the NRC staff considers the issue resolved since the updated fluence was still determined using NRC-approved, RG 1.190-adherent methods.

The original surveillance capsule withdrawal plan spanning the initial license period, ending in 2020 for Unit 1 and 2021 for Unit 2, has already been completed and, as such, 1brms no part of this evaluation. The licensee stated in the submittal that the levi sed plan is to withdraw Capsule S from Unit 1 at the EOC 28. Given that Surveillance Capsule S is moved to the higher fluence location at the EOC 19 or 20, the requested change to the withdrawal schedule would provide a neutron fluence for the Capsule S test samples at SON, Unit 1 of between 2.81 to 2.96 X 1019 n/cm 2 (E >1 MeV). The maximum fluence at the RPV inside diameter for the license renewal period at SON, Unit 1 (52 EFPY) has been estimated to be 2.66 X 1019 n/cm 2 (E >1 MeV).

Therefore, the revised schedule for Unit 1 will result in the fluence on Capsule S exceeding the peak RPV neutron fluence at 60 years of operation, but will not be greater than twice the peak.

For Unit 2, the licensee stated in the submittal that the revised plan is to withdraw Capsule S from the RPV at the EOC 27. Provided that Surveillance Capsule S is moved to the higher fluence location at the EOC 19 or 20, the requested change to the withdrawal schedule would produce a neutron fluence for the Capsule S test samples of between 2.65 to 2.78X 1019 n/cm 2 (E>1 MeV).

The maximum fluence at the RPV inside diameter for the license renewal period at SON, Unit 2 (52 EFPY) has been estimated to be 2.57 X 1019 n/cm 2 (E>1 MeV). Therefore, the revised schedule for Unit 2 will result in the fluence on Capsule S exceeding the peak RPV neutron fluence at 60 years of operation, but will not be greater than twice the peak.

th In summary, given the standby capsules are relocated to the high fluence locations during the 19 or 20th refueling cycle, the removal of Surveillance Capsule S at the EOC 28 for SON, Unit 1 and at the EOC 27 for Unit 2 meets the intent of ASTM E 185-82, the expectation of the GALL report for the period of extended operation, and the requirements of 10 CFR Part 50, Appendix H; therefore, the NRC staff concludes that the proposed changes to the schedules are acceptable.

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4.0 CONCLUSION

Based on the NRC staff's review of the licensee's January 10, 2013, and July 3, 2013, submittals, the NRC staff concludes that, given the relocation of Capsules Sand W occurs during either the 19th or 20th refueling outages, the revised withdrawal dates of EOC 28 for Unit 1 and EOC 27 for Unit 2, for Surveillance Capsule S at SON, are acceptable and will meet the expectations of ASTM E185-82, the GALL report, and the requirements of 10 CFR Part 50, Appendix H.

5.0 REFERENCES

1. Shea, J. W., Tennessee Valley Authority, letter to U.S. Nuclear Regulatory Commission, "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated January 10, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML130320295).

2. Shea, J. W., Tennessee Valley Authority, letter to U.S. Nuclear Regulatory Commission, "Response to NRC Request for Additional Information Regarding Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision," dated July 3, 2013 (ADAMS Accession No. ML13192A034).

3. Section XI.M31 , NUREG-1801, Revision 2, "Generic Aging Lessons Learned (GALL)

Report," Nuclear Regulatory Commission, December 2010.

4. Tennessee Valley Authority, submittal to U.S. Nuclear Regulatory Commission, "Sequoyah Nuclear Plant, Units 1 and 2, License Renewal Application," dated January 7,2013 (ADAMS Accession No. ML130240007).

5. Westinghouse Report WCAP-8233, Revision 0, "Tennessee Valley Authority Sequoyah, Unit No.1 Reactor Vessel Radiation Surveillance Program," December 1973.

6. Westinghouse Report WCAP-8513, Revision 0, "Tennessee Valley Authority Sequoyah, Unit No.2 Reactor Vessel Radiation Surveillance Program," November 1975.

7. Westinghouse Report WCAP-15224, Revision 0, "Analysis of Capsule Y from the Tennessee Valley Authority Sequoyah Unit 1 Reactor Vessel Radiation Surveillance Program," dated June 1999.

8. Westinghouse Report WCAP-15320, Revision 0, "Analysis of Capsule Y from the Tennessee Valley Authority Sequoyah Unit 2 Reactor Vessel Radiation Surveillance Program," dated December 1999.

9. Westinghouse Report WCAP-17539-NP, Revision 0, "Sequoyah Units 1 and 2 Time-Limited Aging Analysis on Reactor Vessel Integrity."

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10. Westinghouse Report WCAP-16083-NP-A, Revision 0, "Benchmark Testing of the FERRET Code for Least Squares Evaluation of Light Water Reactor Dosimetry," dated May 31, 2006 (ADAMS Accession No. ML061600256).

Principal Contributor: P. Purtscher Date: September 27,2013

September 27,2013 Mr. Joseph W. Shea Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 SUB~IECT: SEOUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - REVISE THE REACTOR PRESSURE VESSEL MATERIAL SURVEILLANCE CAPSULE WITHDRAWAL SCHEDULE DUE TO LICENSE RENEWAL AMENDMENT (TAC NOS. MF0631 AND MF0632)

Dear Mr. Shea:

By letter dated January 10, 2013, and supplemented by letter dated July 3, 2013, Tennessee Valley Authority submitted a revised reactor pressure vessel (RPV) material surveillance specimen withdrawal schedule for Sequoyah Nuclear Plant (SON), Units 1 and 2. The revised schedule will support license renewal of the SON, Units 1 and 2 operational licenses for an additional 20 years.

The NRC staff has completed its review of the revised RPV surveillance capsule withdrawal schedule and concludes that, given the relocation of Capsules Sand W occurs during the 19th or 20 th refueling outages, the revised withdrawal dates of end of cycle (EOC) 28 for Unit 1 and EOC 27 for Unit 2, for surveillance capsule S at SON, are acceptable. The revised schedule will meet the expectations of American Society for Testing and Materials E 185-82, NUREG-1801, Revision 2, "Generic Aging Lessons Learned (GALL) Report," and the requirements of Title 10 of the Code of Federal Regulations, Part 50, Appendix H.

Sincerely, IRA!

Siva P. Lingam, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosure:

Safety Evaluation cc w/encl: Distribution via ListServ Distribution:

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NAME SLingam BClayton SRosenberg DMorey BHarris DBroaddus ( FSaba for)

DATE 9/27/13 9/27/13 8/22/13 8/30/13 9/4113 9/27/13 OFFICIAL RECORD COPY