NL-15-098, Sequoyah, Units 1 and 2 - Revision to Commitment No. 28 and Review of Impacts to the SQN Reactor Vessel Internals Aging Management Program Due to Dislodged Reactor Vessel Surveillance Capsules in Unit 1 Reactor
| ML15197A176 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/10/2015 |
| From: | Shea J W Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CNL-15-098 Rev 1 | |
| Download: ML15197A176 (22) | |
Text
Tennessee Valley Authority , 1101 Market Street , Chattanooga , Tennessee 37402 CNL-15-098 Revision 1 July 10 , 2015 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327 and 50-328 10 CFR 50.4 10 CFR Part 54
Subject:
Sequoyah Nuclear Plant -Revision to Commitment No. 28 and Review of Impacts to the SQN Reactor Vessel Internals Aging Management Program Due to Dislodged Reactor Vessel Surveillance Capsules in Unit 1 Reactor
References:
- 1. TVA Letter to NRC , "Sequoyah Nuclear Plant, Units 1 and 2 License Renewal" , dated January 7, 2013 2. TVA letter to NRC , "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated January 10 , 2013 3. NRC letter to TVA , " Sequoyah 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)," dated September 27 , 2013 4. TVA letter to NRC, " Sequoyah Nuclear Plant -Revision to Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule for License Renewal," dated May 14, 2015 5. NRC letter to TVA, "Safety Evaluation Report Related to the Sequoyah Nuclear Plant , Units 1 and 2, License Renewal Application (TAC NOS. MF0481 and MF0482), dated January 29 , 2015 6. Westinghouse Report, "Sequoyah Unit 1U1R2010-YR Reactor Vessel IWI & Loose Part Inspections Field Service Report , dated May 2015 7. Westinghouse Procedure WDl-STD-088, Rev. 12 for Sequoyah Unit 1 U.S. Nuclear Regulatory Commission CNL-15-098 Revision 1 Page2 July 10, 2015 During the Sequoyah Nuclear Plant (SQN) Unit 1 end of cycle (EOC) R20 outage, inspections of the Unit 1 reactor vessel internals revealed that the reactor pressure vessel (RPV) material surveillance capsules S and W had become dislodged from their intact designated baskets and were no longer available to provide fluence data. These capsules had been relocated in Unit 1 EOC R19. ASME Section XI inservice inspections of the Sequoyah (SQN) Unit 1 reactor vessel internals identified that specimen pieces of the capsules had come in contact with some of the reactor vessel internals components.
On April 30, 2015, TVA conducted a phone call with Nuclear Regulatory Commission (NRC) staff to inform the staff of the damage to the Unit 1 Capsules S and W. The NRC requested that SQN evaluate the impacts to the SQN License Renewal Application (LRA) (Reference 1). TVA has evaluated the following potential impacts: (1) the reactor vessel surveillance capsule withdrawal schedule, (2) LRA commitment changes, (3) potential impacts to MRP-227-A assumptions that support the SQN Reactor Vessel Internals Aging Management Program defined in the LRA, and (4) Potential Aging Management mechanisms involved in the damaged S and W Capsules.
Results of the impact reviews are provided herein. Planned corrective actions to prevent recurrence are described in this letter. TVA's evaluation of the impact to the SQN LRA are addressed below. 1. Reactor Vessel Surveillance Capsule Withdrawal Schedule In Reference 2, TVA provided the NRC with a revised Reactor Vessel Surveillance Capsule Withdrawal Schedule for review and approval.
As discussed in Reference 2, relocation of SQN Unit 1 Capsule S to a location of higher fluence was required to ensure that a Unit 1 capsule withdrawal schedule consistent with the expectations of American Society for Testing and Materials (ASTM) E-185-82 and compliance with 10 CFR 50, Appendix H could be attained.
The Unit 1 withdrawal schedule required Capsule S to be removed during U1 EOC R28 outage. The capsule withdrawal schedule revision was approved by the NRC in Reference
- 3. SQN relocated the Unit 1 Capsule S to the 40-degree higher fluence location during the EOC R19 outage. Capsule W was also relocated during EOC R19 outage to a location of higher fluence (220-degree) for future removal to support a potential plant life extension beyond 60 years. The Capsule W withdrawal schedule (Standby) is unchanged from the current Final Safety Analysis Report. Because the Capsule S is no longer available, the revised capsule withdrawal schedule provided to the NRC in Reference 2 and approved by the NRC in Reference 3 cannot be completed.
In Reference 4, TVA submitted a second revised Reactor Vessel Surveillance Capsule Withdrawal Schedule for SQN Unit 1 to the NRC for review. The second revised schedule complies with the expectations of ASTM E-185-82, NUREG-1801, Revision 2, "Generic Aging Lessons Learned (GALL) Report," and the requirements of 10 CFR 50, Appendix H.
U.S. Nuclear Regulatory Commission CNL-15-098 Revision 1 Page 3 July 10, 2015 2. LRA Commitment Changes In letter dated January 7, 2013 (Reference 1), TVA submitted an application to the NRC to renew the operating licenses for SQN Units 1 and 2. The request would extend the licenses for an additional 20 years beyond the current expiration dates. NRC developed its final Safety Evaluation Report (SER) (ML 15021A356) to document findings associated with the safety review of TVA's LRA and supporting documentation for SQN. In Reference 5, NRC determined that TVA's LRA was complete and closed all open items. Appendix A of the NRC SER provides a list of TVA commitments related to SQN's aging management programs.
The list included Commitment No. 28 that addresses SQN's Reactor Vessel Surveillance Program. Commitment No. 28 (Item B) provides a schedule for withdrawal of SQN's capsules to meet the ASTM E-185-82 requirements, including the possibility of operation beyond 60 years. Commitment No. 28 (Item B) 8. Revise Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM E 185-82 requirements, including the possibility of operation beyond 60 years (refer to TVA Letter to NRG, "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated 01110113, ML 13032A251; NRG final safety evaluation report approved on 09127113, ML 13240A320)
As noted above, SQN Unit 1 cannot comply with the specimen withdrawal schedule for Capsule S as defined by the TV A letter to the NRC referenced in this commitment.
As noted previously, TVA has submitted a revised capsule withdrawal schedule (Reference
- 5) that complies with (ASTM) E 185-82, NUREG-1801, Revision 2, "Generic Aging Lessons Learned (GALL) Report," and the requirements of 10 CFR 50, Appendix H. Accordingly, TVA is proposing a revision to Commitment No. 28 to divide Item B into two parts (B.1 and B.2) as follows: (Note that deletions are struck-through and additions are underlined.
Revised Commitment No. 28 (Item 8) 8. 1 Revise Unit 2 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM-E185-82 requirements, including the possibility of operation beyond 60 years (refer to the TVA Letter to NRG, "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated 01110113, ML 13032A251; NRG final safety evaluation report approved on 09127113, ML 13240A320).
8.2 Revise
Unit 1 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM E 185-82 requirements, including the possibility of operation beyond 60 years (refer to TVA Letter to NRG, "ae(;/l:JO]'BR Reactor PtfJSSl:JFe
'Jesse.' al:JNe.i/laRGe Capsl:J.'e VJ.Jit/:Jdrav;a.'
So/:Jedl:J.'e U.S. Nuclear Regulatory Commission CNL-15-098 Revision 1 Page4 July 10, 2015 Re*l-fsioR D1:1e to UGBRSB ReRew-a.'
AmeRdFRBRt," dated 01110/13, ."AL 13032A2§1;
!\IRC FSER afJfJFOv.ed OR 09127/13, ML 13240A320 Sequoyah Nuclear Plant -Revision to Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule for License Renewal), dated May 14. 2015. Enclosure 1 provides the revised Commitment No. 28. 3. Potential Impact to MRP-227-A Assumptions The Westinghouse Reactor Vessel Internals group reviewed the results of the SQN Unit 1 Reactor Vessel Internals Foreign Object Search and Retrieval (FOSAR) effort and ASME Section XI VT-3 lnservice Inspections to determine the possibility of internals damage associated with the dislodged RPV surveillance capsule loose parts. Completed structural evaluation and disposition reports as well as the chemistry evaluation and disposition reports were also reviewed.
The results are reported in Enclosure
- 2. References 6 and 7 support the Westinghouse conclusion that the observed Reactor Vessel Internals components were within existing design considerations and qualification of the components.
This conclusion was based on: (1) there was no measurable impact to original design data, (2) there was no risk to structural integrity for any loading condition, (3) there was no impact on corrosion potential as a result of dissolution of materials in the primary water, and (4) there was no risk for increased crack initiation as a result of localized stress, noting specifically the lower support casting and instrumentation guide extension evaluation.
References 6 and 7 are available at the site (TVA offices) for review. To determine if the inspection findings necessitated a change to the MRP-227-A requirements and inspection protocols for the SQN Reactor Vessel Internals (RVI) aging management program (AMP}, the following were considered:
- a. Did aging related degradation contribute to the failure of the specimen capsule? b. Did the surveillance capsule loose parts cause damage to the reactor vessel internals components that would impact their design function or expected life? c. Do the indications cause a change to the SQN Unit 1 RVI AMP MRP-227-A requirements and protocols (e.g., expansion to primary)?
Factored into this review is the following SQN Unit 1 Operating Experience (OE) relative to this event. a. No evidence of increases in fluence on components other than what would be expected as a result of operation.
- b. No evidence of increases in temperature.
- c. No material changes due to chemicals in the primary water. d. No evidence of cracking.
- e. No indication of structural frequency shifts. f. Multiple indications of superficial wear that are not isolated to being caused by this event.
U.S. Nuclear Regulatory Commission CNL-15-098 Revision 1 Page 5 July 10 , 2015 The Westinghouse OE evaluation for the dislodged SQN Unit 1 capsule specimens concluded that without a driver for degradation initiation or propagation, there is no basis to identify or technically justify a cause for concern that this event would cause a noncompliance or need for change in the existing MRP-227-A.
As a result, Westinghouse concluded that the assessment for MRP-227-A applicability , including consideration of the specific requirements of NRC SER Applicant Licensee Action Items (A/LAI) 1 and 2, remain valid as is. There is no impact to the existing SON Reactor Vessel Internals aging management programs that was previously reviewed and approved by the NRC in Reference 5. 4. Potential Aging Management mechanisms involved in the damaged capsules.
The TVA and Westinghouse root cause analyses (RCAs) for the damaged specimens in the SON Unit 1 Reactor Vessel are complete. The direct cause of this event is installation errors and installation procedural inadequacies. Specimen and specimen basket failure due to unanticipated potential aging effects was not identified as a direct or contributing cause. Enclosure 1 provides the proposed revision to TVA's Commitment No.28 (Item B). Enclosure 2 provides an Evaluation of Failed Specimen Capsules on the Reactor Internals Aging Management Program Plan at Sequoyah Unit 1. Please address any questions regarding this submittal to Erin Henderson , SQN Site Licensing Manager , at (423) 843-7170.
I declare under penalty of perjury that the foregoing is true and correct. Executed on this 10th day of July 2015. ice President Nuclear Licensing Enclosures
- cc: 1. Proposed Revisions to Commitment No. 28 and LRA Sections A.1.35 and B.1.35 2 Westinghouse Letter L TR-RIAM-15-40-NP , RO , Evaluation of Failed Specimen Capsules on the Reactor Internals Aging Management Program Plan at Sequoyah Unit 1, (Non-Proprietary)
Regional Administrator, Rll NRC Project Manager, Sequoyah License Renewal Project NRC Senior Resident Inspector , Sequoyah Nuclear Plant ENCLOSURE 1 Tennessee Valley Authority Sequoyah Nuclear Plant Units 1 and 2, Proposed Revisions to Commitment No. 28 and LRA Sections A.1.35 and 8.1.35 Current Commitment No.28 28 A. Revise Reactor Vessel Surveillance Program procedures to consider B.1.35 SQN1: Prior to Letter the area outside the beltline such as nozzles, penetrations and 03/17/2020 ML 13190A276 discontinuities to determine if more restrictive P-T limits are required than SQN2: Prior to (7/1/13) would be determined by just considering the reactor vessel beltline 03/15/2021 materials.
B. Revise Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM-E185-82 requirements, including the possibility of operation beyond 60 years (refer tot he TVA Letter to NRC, "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated 01/10/13, ML13032A251; NRC final safety evaluation report approved on 09/27/13, ML 13240A320).
C. Revise Reactor Vessel Surveillance Program procedures to withdraw and test a standby capsule to cover the peak fluence expected at the end of the period of extended operation.
Revised Commitment No. 28 28 A. Revise Reactor Vessel Surveillance Program procedures to consider B.1.35 SQN1: Prior to Letter the area outside the beltline such as nozzles, penetrations and 03/17/2020 ML13190A276 discontinuities to determine if more restrictive P-T limits are required SQN2: Prior to (7/1/13) than would be determined by just considering the reactor vessel beltline 03/15/2021 materials.
fil Revise Unit 2 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM-E185-82 requirements, including the possibility of operation beyond 60 years (refer to the TVA Letter to NRC, "Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated 01/10/13, ML 13032A251; NRC final safety evaluation report approved on 09/27/13, ML 13240A320).
8.2 Revise
Unit 1 Reactor Vessel Surveillance Program 12rocedures to incor12orate an NRC-a1212roved schedule for ca12sule withdrawals to meet ASTM-E185-82 reguirements, including the 12ossibility of 012eration beyond 60 years (refer to the TVA Letter to NRC, Seguoyah Nuclear Plant, Revision to Reactor Pressure Vessel Surveillance Ca12sule Withdrawal Schedule for License Renewal dated May 14, 2015). c. Revise Reactor Vessel Surveillance Program procedures to withdraw and test a standby capsule to cover the peak fluence expected at the end of the period of extended operation.
Changes to LRA Section A.1.35, Reactor Vessel Surveillance Program, follow with additions underlined and deletions line through. The Reactor Vessel Surveillance Program will be enhanced as follows. Revise Reactor Vessel Surveillance Program procedures to consider the area outside the beltline such as nozzles, penetrations and discontinuities to determine if more restrictive temperature limits are required than would be determined by just considering the reactor vessel beltline materials.
Revise Unit 2 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM E 185-82 requirements, including the possibility of operation beyond 60 years (refer to the TVA Letter to NRC, Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment," dated January 10, 2013 (ML13032A251)).
Revise Unit 1 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM E 185-82 requirements.
including the possibility of operation beyond 60 years (refer to the TV A Letter to NRC. Sequoyah Nuclear Plant. Revision to Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule for License Renewal dated May 14. 2015). Changes to LRA Section 8.1.35, Reactor Vessel Surveillance Program, follow with additions underlined and deletions line through. The following enhancements will be implemented prior to the period of extended operation.
Element Affected Enhancement
- 4. Detection of Aging Effects Revise Unit 2 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM-E185-82 requirements, including the possibility of operation beyond 60 years (refer to the TV A Letter to NRC, Sequoyah Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule Revision Due to License Renewal Amendment, dated January 10, 2013(ML13032A251)).
Revise Unit 1 Reactor Vessel Surveillance Program procedures to incorporate an NRG-approved schedule for capsule withdrawals to meet ASTM E 185-82 requirements, including the possibility of operation beyond 60 years {refer to the TVA Letter to NRC, Sequoyah Nuclear Plant, Revision to Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule for License Renewal dated May 14, 2015}.
ENCLOSURE 2 Tennessee Valley Authority Sequoyah Nuclear Plant, Unit 1 Westinghouse Letter L TR-RIAM-15-40-NP, RO, Evaluation of Failed Specimen Capsules on the Reactor Internals Aging Management Program Plan at Sequoyah Unit 1 (Non-Proprietary)
oooooo