RA-19-0281, Response to NRC Request for Additional Information for the Fall 2018 Oconee Unit 1 Steam Generator Tube Rupture Inspection Report (RA-19-0093)
| ML19213A010 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/31/2019 |
| From: | Dalton S Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-19-0281 | |
| Download: ML19213A010 (4) | |
Text
( ~ DUKE ENERGY Serial: RA-19-0281 July 31, 2019 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 OCONEE NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-269 I RENEWED LICENSE NO. DPR-38 Sheila Dalton Manager - Nuclear Support Services Oconee Nuclear Station Duke Energy ON03CP I 7800 Rochester Hwy Seneca, SC 29672 864.873.3657 Sheila.Dalton@duke-energy.com 10 CFR 50.55
SUBJECT:
Response to NRC Request for Additional Information for the Fall 2018 Oconee Unit 1 Steam Generator Tube Rupture Inspection Report (RA 0093)
REFERENCES:
- 1. Duke Energy Letter, Oconee Unit 1, Refuel 30 (O1R30) lnservice Inspection (ISi) and Steam Generator lnservice Inspection (ISi) Report, Fifth 10-Year ISi Interval (RA 0093), dated February 07, 2019 (ADAMS Accession No. ML19042A098).
- 2. NRC Email from Audrey Klett to Art Zaremba, NRG Request for Additional Information for Oconee SGTIR 01R30, dated July 08, 2019.
Ladies and Gentlemen:
By letter dated February 07, 2019, Duke Energy Carolinas, LLC (Duke Energy) submitted the Oconee Unit 1, Refuel 30 (01 R30) lnservice Inspection (ISi) and Steam Generator lnservice Inspection (SG-ISI) Report (Reference 1 ). By the email dated July 08, 2019 (Reference 2), the NRC requested additional information regarding the SG-ISI report. The Duke Energy Response to the request for information (RAI) is provided in Enclosure 1.
This submittal contains no new regulatory commitments. Should you have any questions concerning this letter, or require additional information, please contact Art Zaremba, Manager -
Nuclear Fleet Licensing, at 980-373-2062.
Sincerely, Sheila Dalton Manager - Nuclear Support Services, Oconee Nuclear Station
U.S. Nuclear Regulatory Commission Serial: RA-19-0281
Enclosure:
Page 2 Duke Energy Response to NRC Request for Additional Information for the Fall 2018 Oconee Unit 1 Steam Generator Tube Rupture Inspection Report (RA-19-0093) cc:
(w/ enclosure)
A. Klett, NRC Project Manager, NRR L. Dudes, NRC Regional Administrator, Region II A. Ruh, NRC Sr. Resident Inspector (Acting), Oconee Nuclear Station
U.S. Nuclear Regulatory Commission Serial: RA-19-0281 Enclosure Duke Energy Carolinas, LLC Serial# RA-19-0281 Enclosure, Page 1 Duke Energy Response to NRC Request for Additional Information for the Fall 2018 Oconee Unit 1 Steam Generator Tube Rupture Inspection Report (RA-19-0093)
- . U.S. Nuclear Regulatory Commission Serial: RA-19-0281 NRC Request:
Enclosure, Page 2 The staff requests the licensee to discuss whether a fully probabilistic OA methodology was used to project the condition of the SG tubes at Oconee, Unit 1.
If a fully probabilistic methodology was not used, then the staff requests the licensee to address the following:
- a. Describe the simplified analysis methodology used and the basis for its acceptability.
- b. Given the number of flaws identified at Oconee, Unit 1 and that a previous OA in 2012 slightly underpredicted the upper value of flaw depth, discuss any analyses performed to determine that a fully probabilistic analysis was not needed (e.g.,
Section 8.2.4 of the Steam Generator Integrity Assessment Guidelines provides a possible approach).
Duke Response:
Fully probabilistic operational assessments covering one cycle of operation were performed for Oconee Unit 1. The Operational assessments passed the acceptance criterion of a projected probability of burst less than or equal to 0.05 with 50% confidence for each steam generator.
The operational assessments followed the EPRI Steam Generator Management Program:
Steam Generator Integrity Assessment Guidelines, Revision 4, 3002007571, June 2016. The operational assessments were performed to address the number of indication observed and the indication shapes.