ML113000356

Upcoming Steam Generator Tube Inservice Inspection

ML113000356
Person / Time
Site:	Prairie Island
Issue date:	11/10/2011
From:	Thomas Wengert Plant Licensing Branch III
To:	Schimmel M Northern States Power Co
Wengert, Thomas J, NRR/DORL, 415-4037
References
TAC ME7371
Download: ML113000356 (4)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555*0001 November 10, 2011 Mr, Mark A. Schimmel Site Vice President Prairie Island Nuclear Generating Plant Northern States Power Company -Minnesota 1717 Wakonade Drive East Welch, MN 55089-9642 PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 -UPCOMING STEAM GENERATOR TUBE INSERVICE INSPECTION (TAC NO. ME7371)

Dear Mr. Schimmel:

Inservice inspections of steam generator (SG) tubes playa vital role in assuring SG tube integrity.

A telephone 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 Prairie Island Nuclear Generating Plant, Unit 2 refueling outage. This 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 call. The NRC staff will document a summary of the conference call, including any material that you provide to the NRC staff in support of the call. If you have any questions regarding this matter, please contact me at (301) 415-4037, Sincerely, Thomas J. Wengert, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-306

Enclosure:

As stated cc w/encl: Distribution via ListServ STEAM GENERATOR TUBE INSPECTION DISCUSSION POINTS The following discussion points have been prepared to facilitate the conference call arranged with the licensee to discuss the results of the steam generator (SG) tube inspections to be conducted during the upcoming spring 2012 refueling outage at Prairie Island Nuclear Generating Plant, Unit 2. 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 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. Discuss any trends in the amount of primary-to-secondary leakage observed during the recently completed cycle. Discuss whether any secondary side pressure tests were performed during the outage and the associated results. Discuss any exceptions taken to the industry guidelines. 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. 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). Describe repair/plugging plans. Describe in-situ pressure test and tube pull plans and results (as applicable and if available). 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) Enclosure

-2 if the loose parts were removed from the SG indications of tube damage associated with the loose parts 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.). Discuss any unexpected or unusual results. Provide the schedule for steam generator-related activities during the remainder of the current outage.

November 10, 2011 Mr. Mark A. Schimmel Site Vice President Prairie Island Nuclear Generating Plant Northern States Power Company -Minnesota 1717 Wakonade Drive East Welch, MN 55089-9642 PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 -UPCOMING STEAM GENERATOR TUBE INSERVICE INSPECTION (TAC NO. ME7371)

Dear Mr. Schimmel:

Inservice inspections of steam generator (SG) tubes playa vital role in assuring SG tube integrity.

A telephone 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 Prairie Island Nuclear Generating Plant, Unit 2 refueling outage. This 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 call. The NRC staff will document a summary of the conference call, including any material that you provide to the NRC staff in support of the call. If you have any questions regarding this matter, please contact me at (301) 415-4037.

Sincerely, IRA! Thomas J. Wengert, Senior Project Manager Plant Licensing Branch 111-1 Division of Operating Reactor licenSing Office of Nuclear Reactor Regulation Docket No. 50-306

Enclosure:

As stated cc w/encl: Distribution via ListServ DISTRIBUTION:

PUBLIC LPL3-1 R/F RidsNrrDorlLpl3-1 Resource RidsNrrLABTully Resource RidsNrrDciCsgb Resource AObodoako, NRR RidsRgn3MailCenter Resource RidsOgcMailCenter Resource KKarwoski, NRR RidsAcrsAcnw

_MaiICTR Resource RidsNrrPMPrairielsland Resource AJohnson, NRR DHiIIs, Rill AShaikh, Rill ADAMS ACCESSION NO'.. ML113000356 OFFICE NRR/LPL3-1/PM NRR/LPL3-1/LA NRR/DCIICSGB/BC (A) NRR/LPL3-1/BC NRR/LPL3-1/PM NAME TWengert BTuily VCusumano RPascarelli ITBeftz for TWengert DATE 11/01111 11/01/11 11/04111 11/10/11 11/10/11 OFFICIAL RECORD COpy