ML13059A288

Wolf Creek Generating Station - Email from Licensee Clarifying Information Ongoing SG Inspection Results for RFO 19 (TAC No. MF0736)

ML13059A288
Person / Time
Site:	Wolf Creek
Issue date:	02/27/2013
From:	Wagner P G Wolf Creek
To:	Lyon F E Plant Licensing Branch IV
Lyon C F
Shared Package
ML13058A178	List: ML13058A183 ML13058A207 ML13059A288 ML13059A312
References
TAC MF0736
Download: ML13059A288 (2)

Text

From:Wagner Pat GTo:Wideman Steve G; Lyon, FredCc:Muilenburg William T; Peabody, Charles; Kopriva, Ron; Herrman Paul J; Broschak John P; Westman Mike J; Fredrickson Kenneth L; Tarr Jeff A; Broschak John P; Herrman Paul J; TurnerArthur P; Dave Ayers; Kurt Crytzer; jukeim@WCNOC.com; nfarenbaugh@anatecintl.com; Lagally, Herman O.; Brandon Momeyer; Helen CothronSubject:RE: Steam Generator Inspections for Upcoming RFODate:Wednesday, February 27, 2013 1:17:49 PMAttachments:image001.pngDIVIDER PLATE_UT PLOT_rev 1.pdfI would like to provide some additional / clarifying information prior to the call tomorrow. Related to Item 1, the Ultrasonic Testing has bounded the indication at 0.1 inches deep by 2 inches long (see the attached UT Plot for more information). Related to Item 2, See the following graph related to the Condition Monitoring limit for the circ indication. The steeper slope is tensile instability which relates to separation within the tubesheet. The shallower slope presumes that tube could bend at top oftubesheet and is conservative relative to locations within the tubesheet. In any case, the allowable percent degraded area (PDA) for 3 delta P consideringall uncertainties is 58% and the measured PDA is 11%. Pat From: Wideman Steve G Sent: Tuesday, February 26, 2013 8:29 AMTo: 'Lyon, Fred'Cc: Muilenburg William T; Peabody Charles A; 'Ron.Kopriva@nrc.gov'; Wagner Pat G; Herrman Paul J; Broschak John P; Westman Mike J; Fredrickson Kenneth LSubject: RE: Steam Generator Inspections for Upcoming RFO Fred - in accordance with the below email of February 1, 2013, this email is to make you aware of two items identified during the current refuelingoutage Steam Generator (SG) Inspections. If it is determined that a conference call is needed, please let Bill Muilenburg and myself know. Item 1 - During the primary bowl scan of SG 'A' Hot Leg as part of the Westinghouse Nuclear Safety Advisor Letter NSAL-12-1, "Steam GeneratorChannel Head Degradation," a rust color spot was identified approximately 6 inches down from the face of the tubesheet along the divider plateto bowl weld (see attached photo). Following identification of this area, UT was attempted of the area from outside the SG primary bowl. Thefirst attempt was unsuccessful utilizing a straight beam UT probe due to interferences with the SG support beam. Subsequently, a 60-degree LWave UT probe was utilized to characterize the area. This UT determined that the flaw was approximately 0.1 inches deep by approximately 1 inch long. No width could be obtained. This item is currently being evaluated by WCNOC and Westinghouse to determine what the future courseof action will be necessary. Item 2 - During the Top-of-Tubesheet eddy current inspection, a circumferential indication was confirmed in SG 'B' Hot Leg (17,89) ~TTS -6.46"which is located at a bulge indication. Due to this indication, 100% of the tubes containing BLG and/or OXP will be inspected in SG 'B' within theinspection region. Also, 20% of the tubes containing BLG and/or OXP within the inspection region for SGs 'A', 'C', and 'D' will need to beinspected. It should be noted that as part of the original inspection program that greater than 20% of the BLG and/or OXP within the tubesheet inSG 'A', 'C', and 'D' are already being inspected. Therefore, currently there is no additional testing required in SG 'A', 'C', and 'D'. Steve WidemanWCNOC Licensing 620-364-4037 From: Lyon, Fred [1] Sent: Friday, February 01, 2013 5:35 AMTo: Wideman Steve G; Elwood, Thomas BCc: Muilenburg William T; Maglio, Scott A; Hartman, Thomas; Peabody Charles ASubject: Steam Generator Inspections for Upcoming RFO As you are may recall, the steam generator branch (ESGB) participates in conference calls with a handful of licensees performing steamgenerator inspections every outage season. They have not selected Wolf Creek or Callaway for such a call during their upcoming outages;however, please notify me if one (or more) of the following circumstances is identified during the outage: 1. If a degradation mechanism (other than wear from loose parts) is observed that has not been previously observed in these steamgenerators. 2. If degradation of steam generator secondary side internals is observed that has not been previously observed in these steam generators. 3. If a flaw is more severe than expected, or if the number of flaws identified are more than expected. 4. If an in-situ pressure test is performed. If you experience one (or more) of the above, please let me know. The staff may request that you participate in a conference call to discussyour findings.

If you are not performing any steam generator tube inspections this upcoming outage, please let me know. Thanks, Fred