ML13190A284
| ML13190A284 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 07/10/2013 |
| From: | Joel Wiebe Plant Licensing Branch III |
| To: | Pacilio M Exelon Generation Co |
| Joel Wiebe, NRR/DORL 415-6606 | |
| References | |
| TAC MF0659 | |
| Download: ML13190A284 (3) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 10, 2013 IVIr. Michael J. Pacilio Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)
Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD STATION, UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR REFUELING OUTAGE 16 (TAC NO. MF0659)
Dear Mr. Pacilio:
By letter to the U.S. Nuclear Regulatory Commission (NRC) dated February 5,2013, Exelon Generation Company, LLC submitted its Steam Generator Tube Inspection Report for Braidwood Station, Unit 2, refueling outage 16.
The NRC staff is reviewing your submittal and has determined that additional information is required to complete the review. The specific information requested is addressed in the enclosure to this letter. A response is requested within 30 days of the date of this letter.
If circumstances result in the need to revise the response date. please contact me at (301) 415-6606.
Sincerely, el S. Wiebe, Senior Project Manager lant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-457
Enclosure:
Request for Additional Information cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION BRAIDWOOD STATION, UNIT 2 DOCKET NO. STN 50-457 In reviewing the Exelon Generation Company, LLC's (Exelon) submittal dated February 5, 2013, regarding the Steam Generator [SG] Tube Inspection Report for Braidwood Station, Unit 2, refueling outage 16 (RF016), the NRC staff has determined that the following information is needed in order to complete its review:
- 1. Discuss the scope and results of any secondary side visual inspections that were performed in RF016 including the results of any foreign object search and retrieval inspections.
- 2. In Sections 5.1.4 and 5.2.1 of Exelon's February 5, 2013, submittal, it states that the tube at Row 44 Column 47 (R44C47) in SG C was found to contain the characteristic signature indicative of high residual stress (i.e. a -2 sigma tube with no voltage offset between the straight and U-bend portions of the tube). Since it appears that this tube was not captured in its previous search for -2 sigma tubes, discuss the scope and results of any additional reviews that you might have performed to ensure you have identified all
-2 sigma tubes.
- 3. Section 5.2.1. also discusses the additional inspections performed on the 71 previously known -2 sigma tubes. Clarify if these inspections were performed on the tube at R44C47 and any other newly discovered -2 sigma tubes.
- 4. Exelon's letter indicated that the SGs had accumulated 241.06 effective full power months (EFPMs) of operation and that Braidwood, Unit 2, outage was at 31.06 EFPMs within the first 60 EFPM period. Since the first period (120 EFPM) starts after the first inservice inspection (lSI), clarify whether the SGs at Braidwood, Unit 2, had operated for 241.06 EFPMs since the first lSI since commencement of commercial operation.
- 5. In several instances. a 25 percent inspection of specific locations (e.g., pre-heater baffle plate expansions) was performed. If the 2012 inspections were nearest to the mid-point of the 60 EFPM period, confirm that 50 percent of these locations had been inspected since the start of the 60 EFPM period.
- 6. Discuss the scope and results of any inspections of the SG channel head.
Enclosure
ML13190A284 Sincerely, JRAJ Joel S. Wiebe, Senior Project Manager Plant Licensing Branch 111-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation LPL3-2 R/F RidsNrrLASRohrer Resource RidsNrrDorlLpl3-2 Resource RidsNrrDorlDpr Resource OFFICE LPL3-2/PM LPL3-2/LA LPL3-2/BC LPL3-2/PM I NAME JWiebe SRohrer JBowen JWiebe DATE 7/10 113 7/3/13 7/10/13 7/10/13