ML082321012

Upcoming Steam Generator Tube Inservice Inspection

ML082321012
Person / Time
Site:	Prairie Island
Issue date:	08/28/2008
From:	Thomas Wengert Plant Licensing Branch III
To:	Wadley M Nuclear Management Co
Wengert, Thomas NRR/DORL 415-4037
References
TAC MD9465
Download: ML082321012 (6)

Text

August 28, 2008 Mr. Michael D. Wadley Site Vice President Prairie Island Nuclear Generating Plant Nuclear Management Company, LLC 1717 Wakonade Drive East Welch, MN 55089

SUBJECT:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 - UPCOMING STEAM GENERATOR TUBE INSERVICE INSPECTION (TAC NO. MD9465)

Dear Mr. Wadley:

Inservice inspections of steam generator (SG) tubes play a vital role in assuring SG tube integrity. The reporting requirements of plant technical specifications typically require submission of a report within 180 days following completion of the inspection. The content of the report includes the following:

1. The scope of inspections performed on each SG,

2. Active degradation mechanisms found,

3. Nondestructive examination techniques utilized for each degradation mechanism,

4. Location, orientation (if linear), and measured sizes (if available) of service induced indications,

5. Number of tubes plugged during the inspection outage for each active degradation mechanism,

6. Total number and percentage of tubes plugged to date, and

7. The results of condition monitoring, including the results of tube pulls and in-situ testing.

A phone conference has been arranged with members of your staff to discuss the ongoing results of the SG tube inspections to be conducted during the upcoming Prairie Island Nuclear Generating Plant, Unit 2 refueling outage. This phone call will occur after the majority of the tubes have been inspected, but before the SG inspection activities have been completed.

Enclosed is a list of discussion points to facilitate this phone conference.

The U.S. Nuclear Regulatory Commission (NRC) staff plans to document a summary of the conference call, including any material that you provide to the NRC staff in support of the call.

Sincerely,

/RA/

Thomas J. Wengert, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-306

Enclosure:

SG Tube Inspection Discussion Points cc w/encl: See next page

The U.S. Nuclear Regulatory Commission (NRC) staff plans to document a summary of the conference call, including any material that you provide to the NRC staff in support of the call.

Sincerely,

/RA/

Thomas J. Wengert, Senior Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-306

Enclosure:

SG Tube Inspection Discussion Points cc w/encl: See next page DISTRIBUTION PUBLIC LPL3-1 r/f RidsNrrDorlLpl3-1 RidsNrrPMTWengert RidsNrrLATHarris RidsOGCRp RidsAcrsAcnw&mMailCenter EWong, NRR RidsRgn3MailCenter KKarwoski, NRR RidsNrrDciCsgb ADAMS Accession: ML082321012

• Per email dated 8/18/2008 NRR-106 OFFICE NRR/LPL3-1/PM NRR/LPL3-1/LA NRR/CSGB NRR/LPL3-1/BC NAME TWengert THarris AHiser*

LJames DATE 08/ 20 /08 08/ 20 /08 08/18/08 08/ 28 /08 OFFICIAL RECORD COPY

Prairie Island Nuclear Generating Plant, Units 1 and 2 cc:

Peter M. Glass Assistant General Counsel Xcel Energy Services, Inc.

414 Nicollet Mall (MP4)

Minneapolis, MN 55401 Manager, Regulatory Affairs Prairie Island Nuclear Generating Plant Nuclear Management Company, LLC 1717 Wakonade Drive East Welch, MN 55089 Manager - Environmental Protection Division Minnesota Attorney General=s Office 445 Minnesota St., Suite 900 St. Paul, MN 55101-2127 U.S. Nuclear Regulatory Commission Resident Inspector's Office 1719 Wakonade Drive East Welch, MN 55089-9642 Administrator Goodhue County Courthouse Box 408 Red Wing, MN 55066-0408 Commissioner Minnesota Department of Commerce 85 7th Place East, Suite 500 St. Paul, MN 55101-2198 Tribal Council Prairie Island Indian Community ATTN: Environmental Department 5636 Sturgeon Lake Road Welch, MN 55089 Nuclear Asset Manager Xcel Energy, Inc.

414 Nicollet Mall (MP4)

Minneapolis, MN 55401 Dennis L. Koehl Chief Nuclear Officer Nuclear Management Company, LLC 414 Nicollet Mall (MP4)

Minneapolis, MN 55401 Joel P. Sorenson Director, Site Operations Prairie Island Nuclear Generating Plant Nuclear Management Company, LLC 1717 Wakonade Drive East Welch, MN 55089

STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS PREPARED BY THE OFFICE OF NUCLEAR REACTOR REGULATION PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 DOCKET NO. 50-306 The following discussion points have been prepared to facilitate the conference call arranged with Nuclear Management Company, LLC (NMC or the licensee) to discuss the results of the steam generator (SG) tube inspections to be conducted during the upcoming fall 2008, Prairie Island Nuclear Generating Plant, Unit 2 refueling outage. This conference call is scheduled to occur towards the end of the planned SG tube inspections, but before the unit completes the inspections and repairs.

The U.S. Nuclear Regulatory Commission staff plans to document a 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 SG, provide a description of the inspections performed including the areas examined and the probes used (e.g., dents/dings, sleeves, expansion-transition, U-bends with a rotating probe), 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 for 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.

ENCLOSURE

7.

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

8.

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 (including the source or nature of the loose part, if known) if the loose parts were removed from the SG indications of tube damage associated with the loose parts

9.

Discuss the scope and results of any secondary side inspection and maintenance activities (e.g., in-bundle visual inspections, feedring inspections, sludge lancing, assessing deposit loading, etc).

10. Discuss any unexpected or unusual results.

11. Provide the schedule for SG-related activities during the remainder of the current outage.