ML080910121

Upcoming Steam Generator Tube Inservice Inspection

ML080910121
Person / Time
Site:	Braidwood
Issue date:	04/04/2008
From:	David M J NRC/NRR/ADRO/DORL/LPLIII-2
To:	Pardee C G Exelon Generation Co
marshall david 415-1547
References
TAC MD8409
Download: ML080910121 (5)

Text

April 4, 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 2 - UPCOMING STEAM GENERATOR TUBE INSERVICE INSPECTION (TAC NO. MD8409)

Dear Mr. Pardee:

Inservice inspections (ISI) of steam generator (SG) tubes play a vital role in assuring that adequate structural integrity of the tubes is maintained. As required by the plant technical specifications, reporting requirements range from submitting a special report, within 15 days following completion of each ISI of SG tubes, that identifies the number of tubes plugged and/or repaired, to submitting a special report, within 12 months following completion of the inspection, that provides complete results of the SG tube ISI. The special report containing the complete results shall include, for example, the following:

1. Number and extent of tubes inspected

2. Location and percent of wall-thickness penetration for each indication of an imperfection

3. Identification of tubes plugged and/or repaired

A conference call has been arranged with members of your staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Braidwood Station, Unit 2, refueling outage. This call will occur after the majority of the tubes have been in spected, but before the SG inspection activities have been completed. Enclosed is a list of discussion points to facilitate this call.

The Nuclear Regulatory Commission staff will document a brief summary of the conference call, as well as any material that you may have provided to the NRC staff in support of the call.

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 50-457

Enclosure:

List of Discussion Points

cc w/encl: See next page

ML080910121

• Per e-mail dated 3/13/08 NRR-106 OFFICE LPL3-2/PM LPL3-2/LA DCI/CSGB/BC LPL3-2/BC NAME MDavid EWhitt AHiser* RGibbs DATE 03/31/08 03/31/08 03/13/08 04/04/08 Braidwood Station, Unit 2 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

Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950

Illinois Emergency Management Agency Division of Disaster Assistance &

Preparedness Via e-mail

Will County Executive Via e-mail

Attorney General Springfield, IL 62701 Via e-mail

Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061

Enclosure STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS PREPARED BY THE OFFICE OF NUCLEAR REACTOR REGULATION BRAIDWOOD STATION, UNIT 2 DOCKET NO. 457

The following discussion points have been prepared by the Nuclear Regulatory Commission (NRC) staff to fac ilitate the conference call arranged with the licensee to discuss the results of the steam generator (SG) tube inservice inspections to be conducted during the upcoming Braidwood Station, Unit 2, refueling outage. This call is scheduled to occur towards the end of the planned SG tube inspection interval, but before the unit completes the inspections and repairs.

The NRC staff will document a brief summary of the conference call, as well as any material that is provided in support of the call.

1. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle.

2. Discuss whether any secondary side pressure tests were performed during the outage and the associated results.

3. Discuss any exceptions taken to the industry guidelines.

4. For each steam generator, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition), the scope of the inspection (e.g., 100 percent of dents/dings greater than 5 volts and a 20 percent sample between 2 and 5 volts), and the expansion criteria.

5. For each area examined (e.g., tube supports, dent/dings, sleeves, etc), provide a summary of the number of indications identified to date of each degradation mode (e.g.,

number of circumferential primary water stress corrosion cracking indications at the expansion transition). For the most significant indications in each area, provide an estimate of the severity of the indication (e.g., provide the voltage, depth, and length of the indication). In particular, address whether tube integrity (structural and accident induced leakage integrity) was maintained during the previous operating cycle. In addition, discuss whether any location exhibited a degradation mode that had not previously been observed at this location at this unit (e.g., observed circumferential primary water stress corrosion cracking at the expansion transition for the first time at this unit).

6. Describe repair/plugging plans.

7. Describe in-situ pressure test and tube pull plans and results (as applicable and if available).

8. Provide the schedule for steam generator-related activities during the remainder of the current outage. 9. Discuss the following regarding loose parts:

• what inspections are performed to detect loose parts,

• a description of any loose parts detected and their location within the SG,

• whether the loose parts were removed from the SG,

• indications of tube damage associated with the loose parts, and

• the source or nature of the loose parts if known.

10. Discuss any unexpected or unusual results.

11. Discuss the results of any secondary side inspections.