ML081640164
| ML081640164 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/16/2008 |
| From: | David M NRC/NRR/ADRO/DORL/LPLIII-2 |
| To: | Pardee C Exelon Generation Co |
| marshall david 415-1547 | |
| References | |
| TAC MD7914 | |
| Download: ML081640164 (4) | |
Text
June 16, 2008 Mr. Charles G. Pardee Chief Nuclear Officer and Senior Vice President Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO STEAM GENERATOR TUBE INSPECTION REPORTS FOR REFUELING OUTAGE A1R13 (TAC NO. MD7914)
Dear Mr. Pardee:
By letters to the Nuclear Regulatory Commission (NRC) dated January 18 and 22, 2008, Exelon Generation Company, LLC (the licensee) submitted information pertaining to the steam generator tube inspections conducted during the 2007 refueling outage A1R13 at Braidwood Station, Unit 1.
The NRC staff is reviewing your submittals and has determined that additional information is required to complete its review. The specific information requested is addressed in the enclosure to this letter. During a discussion with your staff on June 10, 2008, it was agreed that you would provide a response within 60 days from the date of this letter.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1547.
Sincerely,
/RA/
Marshall J. David, Senior Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-456
Enclosure:
Request for Additional Information cc w/encl: See next page
June 16, 2008 Mr. Charles G. Pardee Chief Nuclear Officer and Senior Vice President Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO STEAM GENERATOR TUBE INSPECTION REPORTS FOR REFUELING OUTAGE A1R13 (TAC NO. MD7914)
Dear Mr. Pardee:
By letters to the Nuclear Regulatory Commission (NRC) dated January 18 and 22, 2008, Exelon Generation Company, LLC (the licensee) submitted information pertaining to the steam generator tube inspections conducted during the 2007 refueling outage A1R13 at Braidwood Station, Unit 1.
The NRC staff is reviewing your submittals and has determined that additional information is required to complete its review. The specific information required is addressed in the enclosure to this letter. During a discussion with your staff on June 10, 2008, it was agreed that you would provide a response within 60 days from the date of this letter.
The NRC staff considers that timely responses to requests for additional information help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-1547.
Sincerely,
/RA/
Marshall J. David, Senior Project Manager Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. STN 50-456
Enclosure:
Request for Additional Information cc w/encl: See next page DISTRIBUTION:
PUBLIC LPL3-2 R/F RidsNrrDorlLpl3-2 RidsNrrPMMDavid RidsNrrLAEWhitt RidsAcrsAcnw&mMailCenter RidsNrrDciCsgb RidsRgn3MailCenter AJohnson, NRR ADAMS Accession Number: ML081640164
- See memo dated NRR-088 OFFICE LPL3-2/PM LPL3-2/LA DCI/CSGB/BC LPL3-2/BC NAME MDavid EWhitt AHiser*
RGibbs DATE 06/16/08 06/16/08 06/02/08 06/16/08 OFFICIAL RECORD COPY
Braidwood Station, Unit 1 cc:
Corporate Distribution Exelon Generation Company, LLC Via e-mail Braidwood Distribution Exelon Generation Company, LLC Via e-mail Mr. Dwain W. Alexander, Project Manager Westinghouse Electric Corporation Via e-mail Ms. Bridget Little Rorem Appleseed Coordinator Via e-mail Howard A. Learner Environmental Law and Policy Center of the Midwest Via e-mail Braidwood Resident Inspector U.S. Nuclear Regulatory Commission Via e-mail Illinois Emergency Management Agency Division of Nuclear Safety Via e-mail Will County Executive Via e-mail Attorney General Springfield, IL 62701 Via e-mail Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Via e-mail
Enclosure REQUEST FOR ADDITIONAL INFORMATION BRAIDWOOD STATION, UNIT 1 DOCKET NO. STN 50-456 By letters dated January 18, 2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML080180437), and January 22, 2008 (ADAMS Accession No. ML080220526), the Exelon Generation Company, LLC (the licensee) submitted information pertaining to its 2007 steam generator (SG) tube inservice inspections at Braidwood Station, Unit 1, during refueling outage A1R13. In order to complete its review of the documents listed above, the Nuclear Regulatory Commission staff needs the following additional information:
- 1. Please clarify the following statement in Section 6.0 of your January 18, 2008, letter:
Since only volumetric wear was identified during A1R13, satisfying the structural limit ensures that the SG tube integrity performance criteria for structural integrity, accident induced leakage and operational leakage will be maintained. Is this statement based on the premise that the structural integrity limits were developed based on uniform wall thinning and, as long as these limits are not violated, there will be no leakage during normal operating and accident conditions (because, if the limits were violated, there would be a tube rupture if the wall thinning were uniform)?
- 2. For each refueling outage and SG tube inspection outage since installation of the SGs, please provide the cumulative effective full power months that the SGs have operated.
- 3. Please discuss the scope and results of any secondary side inspections (other than foreign object search and retrieval).
- 4. Several tubes were identified with wear attributed to a loose part. In addition, several loose parts were identified visually. For the indications of wear attributed to loose parts, please discuss how these indications were initially identified (i.e., bobbin and/or rotating probe examination or visual inspection). In addition, discuss whether a turbo mix was used during the evaluation of the bobbin coil data near the top of the tubesheet to assist in the detection of loose parts or wear attributed to loose parts. For the loose parts that were detected visually, please discuss what types of probes were used to inspect the tubes in the vicinity of the part and discuss whether the part or any wear was detected with these probes. If rotating probe examinations of these tubes was not performed, discuss how you confirmed that no wear occurred at these locations (given the potential interference in the bobbin coil data due to the tubesheet and expansion transition).
Please discuss whether any visible signs of wear were present on these tubes.
- 5. Please discuss whether the number of tubes in close proximity is comparable to prior outages and whether the distance between the tubes is similar to what had been observed in the past.