HNP-11-045, 180-Day Steam Generator Tube Inspection Report

180-Day Steam Generator Tube Inspection Report

ML11130A111
Person / Time
Site:	Harris
Issue date:	05/05/2011
From:	Corlett D Progress Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
HNP-11-045
Download: ML11130A111 (8)

Text

Progress Energy.Serial: HNP-11-045 10 CFR 50.4.MAY 5 2011 U.S. Nuclear Regulatory Commission ATTENTION:

Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT Ladies and Gentlemen:

In accordance with the Harris Nuclear Plant (HNP) Technical Specifications (TS), Carolina Power and Light Company (CP&L), doing business as Progress Energy Carolinas, Inc.(PEC), submits the attached 180-Day Steam Generator Tube Inspection Report for HNP.This report has been prepared in accordance with TS 6.9.1.7, Steam Generator Tube Inspection Report, and provides the inspection results for HNP's refueling outage number 16 (RFO- 16).This document contains no new regulatory commitments.

Please refer any question regarding this submittal to me at (919) 362-3137.Sincerely, Dave Corlett Supervisor

-Licensing/Regulatory Programs Harris Nuclear Plant DHC/kab Enclosure cc: Mr. J. D. Austin, NRC Sr. Resident Inspector, HNP Mr. V. M. McCree, NRC Regional Administrator, Region II Mrs. B. L. Mozafari, NRC Project Manager, HNP Progress Energy Carolinas, Inc.Harris Nuclear Plant P. 0. Box 165 New Hill, NC 27562~~DI Enclosure to SERIAL: HNP- 11-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 Harris Nuclear Plant, Unit I (HNP) performed steam generator (SG) inspections for all three SGs during fall 2010 refueling outage 16 (RFO-16).

HNP Technical Specification (TS) 6.9.1.7, Steam Generator Tube Inspection Report, requires Carolina Power and Light Company, (CP&L), doing business at Progress Energy Carolina, Inc.(PEC), to submit a report within 180 days after the initial entry into hot shutdown (MODE 4) following completion of an inspection performed in accordance with the HNP SG Program. The report shall include: A. The scope of inspections performed on each SG B. Active degradation mechanisms found C. Nondestructive examination (NDE) techniques utilized for each degradation mechanism D. Location, orientation (if linear), and measured sizes (if available) of service induced indications E. Number of tubes plugged during the inspection outage for each active degradation mechanism F. Total number and percentage of tubes plugged to date, and G. The results of condition, monitoring, including the results of tube pulls and in-situ testing Initial entry into hot shutdown was on November 8, 2010; therefore, this report is to be submitted by May 7, 2011.HNP SG Design HNP is a three-loop plant where Delta 75 replacement steam generators (RSGs) were installed during the fall 2001 refueling outage 10. The Delta 75 RSGs each have 6307 thermally treated Alloy 690 U-tubes. Each U-tube has a 0.688-inch nominal outside diameter (OD), a 0.040-inch nominal wall thickness and a straight length ranging from 376.69 inches (Row 1) to 382.19 inches (Row 115). The tubes are arranged in a triangular pitch of 0.980 inches in 115 rows (parallel to the tube lane) and 141 columns. The distance between adjacent rows is 0.490 inches and between adjacent columns is 0.8487 inches. The U-bend radii range from 3.25 inches (Row 1) to 59.11 inches (Row 115). The innermost 17 rows are stress relieved after tube bending to minimize the potential for stress corrosion cracking.

The tubesheet is 23.015 inches thick, including the 0.25-inch cladding at the bottom (primary coolant side). The tubes have full depth hydraulic expansion within the tubesheet.

The tubes are supported by nine tube support plates (TSP) which have trefoil broached holes and are made of stainless steel (SA-240 type 405). The flow distribution baffle (FDB) is designed to produce sweeping flow across the tubesheet by having a central flow opening that is intended to minimize sludge deposition area on the tubesheet.

The tubes are supported by four sets of stainless steel (SA-479 Type 405) anti-vibration bars (AVB) in the U-bend portion of the tube bundle.Page 1 of 7 Enclosure to SERIAL: HNP-1 1-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 A. The Scope of Inspections Performed on Each SG (A, B, and C)1. Primary side inspections a) NDE Base Inspection Scope The defined scope implemented in all SGs included the following:

• 25% full length eddy current bobbin probe inspection." In rows one to three, only the straight legs were examined by eddy current bobbin probe inspection." The U-bends were examined by RPC.0 5% eddy current bobbin probe inspection targeted at historical dents.0 20% rotating probe coil (RPC) inspection of the outer periphery tubes -approximately 2 tubes deep and 2 tubes along the blowdown lane, both hot leg and cold leg.* 40% RPC inspection of the row one U-bends for tubes that were not in the 20%inspection last time.* Special interest RPC (freespan signals without historical resolution, bobbin I-code indications).

b) NDE Expanded Inspection Scope SG-A: Secondary side visual inspection found a foreign object which was irretrievable in SG-A and led to a bounding RPC examination of the surrounding tubes. No degradation was observed on either of the tubes which the object was touching or any of the surrounding tubes. The RPC exam did not reveal the presence of the loose part indicating that it is non-conductive.

SG-B: Wear due to a foreign object in SG-B was discovered on a tube by bobbin inspection, which led to a bounding RPC examination of the surrounding tubes.Wear was discovered on two other tubes, which led to a further bounding RPC examination.

No degradation was discovered on the surrounding tubes.Page 2 of 7 Enclosure to SERIAL: HNP-1 1-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 2. Secondary Side Inspections a) Sludge Lancing: Sludge Lancing was performed on all three steam generators to remove debris and corrosion products.

The amounts removed from SG-A, SG-B, and SG-C was 22.5 pounds, 21.0 pounds, and 27.5 pounds, respectively.

The tubesheets were. left in a clean condition.

b) Loose Parts: A Foreign Object Search and Retrieval (FOSAR) of the annulus and tube lane at the top of the tubesheet region of the secondary side of the steam generator was performed for each SG following the performance of top of the tubesheet sludge lancing. Also, a partial in-bundle inspection at the top of the tubesheet was performed for every fifth tube column in SG-C along with a visual inspection for a legacy loose part in SG-A.During the FOSAR in SG-A, a fixed foreign object was found lodged between two outer periphery tubes in the cold leg. This prompted an expansion of the visual inspection in SG-A in the quadrant where the part was found.The visual inspection scope was expanded to an in-bundle examination in SG-B in the quadrant where the foreign object which caused wear was found.Neither of the expanded scope additional visual inspections found additional foreign objects.c) Wrapper Drop: Access to the tubelane without interference was verified.d) Feed Ring and Moisture Separators:

Steam drum and feed ring inspection of all three SGs and FOSAR from these areas was performed.

The steam drum inspection was a visual inspection of the steam drum down to the mid deck and remote visual.inspection of the feedwater spray nozzles, auxiliary feedwater nozzle, inside view of the sludge collector, tube bundle, anti-vibration bars, and top support plate with trefoil holes. No foreign objects or other anomalous conditions were found.B. Active Degradation Mechanisms Found Wear indications resulting from a foreign object were detected in one steam generator, SG-B.A total of three tubes had indications of wear. The part was removed and the tubes plugged, Page 3 of 7 Enclosure to SERIAL: HNP- 11-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 so no further degradation is possible from this foreign object. There was no observed wear at anti-vibration bars (AVBs) or tube support plates (TSPs) in any of the steam generators.

No corrosion related degradation was detected.C. NDE Techniques Utilized for Each Degradation Mechanism ETSS 21998.1 was used for sizing of the freespan wear indications.

D. Location, Orientation (if linear), and Measured Sizes (if available) of Service Induced Indications The only indications found during this inspection were volumetric wear indications in three tubes in the hot leg of SG-B from a loose part. Details are below: Table 1. SG-B Indications Maximum Axial Length Circumferential Depth (%) (in) Extent (in)R 28 C 135 67 0.16 0-21 R 26 C 135 37 0-16 0-17 R 26 C 133 16 0-16 0-17 E. Number of Tubes Plugged During the Inspection Outage for Each Active Degradation Mechanism A total of five tubes were plugged as a result of the inspection as described below for each SG.Steam Generator A Two tubes were stabilized and plugged, R88 C27 and R89 C28. These were stabilized and plugged by administrative decision due to the presence of a foreign object that could not be removed during FOSAR. There were no wear indications on either of the plugged tubes or any of the adjacent tubes included in the bounding RPC examination.

Steam Generator B Three tubes were plugged due to foreign object wear: R28 C135, R26 C135, and R26 C133.Page 4 of 7 Enclosure to SERIAL: HNP- 11-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 Steam Generator C No tubes were plugged in SG-C.F. Total Number and Percentage of Tubes Plugged to Date Each steam generator has a total of 6307 u-tubes. The total numbers of plugged tubes to date for each SG are: Steam Generator A Total number of plugged tubes -5 (0.08%)Steam Generator B Total number of plugged tubes -4 (0.06%)Steam Generator C Total number of plugged tubes -3 (0.05%)G. The Results of Condition Monitoring, Including the Results of Tube Pulls and In-Situ Testing There were three indications of loose parts wear, all in SG-B (see table 1 above). The maximum depth of the wear indication was 67% through-wall.

The depth sizing was performed using EPRI Examination Technique Specification Sheet (ETSS) 21998.1. This is appropriate for indications that do not have large extents in the axial or circumferential direction.

The measurements using ETSS 21998.1 are reported directly and do not include the correlation between actual size and NDE measurement.

The correlational and the NDE uncertainty are included in the condition monitoring limit curve.The measured values using ETSS 21998.1 are the recorded depths. As seen in Figure 1 below (from the Degradation Assessment), the threshold for proof testing for a flaw with an axial length of 0.3 inch is 53% average depth by +Point T M Probe. The second and third tubes in the table 1 above are well below this criterion since even the maximum depth is below the limit for average depth, and therefore meet condition monitoring.

The first tube, however, has a maximum depth higher than the limit set for average depth and hence requires a more detailed analysis.Page 5 of 7 Enclosure to SERIAL: HNP- 11-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO- 16 The maximum depth of the indication in tube R28 C135 falls above the curve (see Figure 1 below) of average depth versus axial length. The maximum depth is 67% through-wall, but the average depth computed from the depth profile is 54%. A calculation determined the condition monitoring limit to be 63.6% for a 0.16-inch long axial thinning flaw. In essence, this calculation extends the axial thinning curve of Figure 1 down to 0.16 inch axial length.Since the average depth of this flaw (54%) is below the condition monitoring limit of 63.6%, this indication met condition monitoring.

The foreign object was removed from the SG and all three tubes with indications were plugged.IDM AXjM Lernth VinJ[_ Uiflfnn Thrnnk4 -0AYx TkJ1 Figure 1. Volumetric Indications Condition Monitoring Limit (+PointTM Probe)The maximum depths of all wear indications detected in two of the three tubes were demonstrated to be below the condition monitoring limits defined in the HNP Degradation Assessment.

Condition monitoring evaluation performed for the indication in the third tube showed that its average depth also falls below the condition monitoring limit for average depth. The maximum depths of the indications were well below the threshold for leakage concern. Therefore, the condition monitoring limits are satisfied for tube integrity and leakage. No tube pulls or in-situ testing was conducted during this inspection.

Page 6 of 7 Enclosure to SERIAL: HNP- 11-045 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-400/RENEWED LICENSE NO. NPF-63 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT FOR RFO-16 COLUMN No. 100 mm~Wi soh SDOLLUNýXl ss COLUMiN. R ) COLUMN NO. I ROW 14O.A AýIleA-REF

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