ML13115A036

Engineering Information Record 51-9198783-000, Watts Bar WBN1C11 SG Inspection 180-Day Report

ML13115A036
Person / Time
Site:	Watts Bar
Issue date:	04/11/2013
From:	Campbell J, Ingram D, Newman V AREVA NP
To:	Office of Nuclear Reactor Regulation
References
51-9198783-000
Download: ML13115A036 (16)

Text

A 20004-019 (11/20/2012)

AREVA AREVA NP Inc.

Engineering Information Record Document No.: 51 - 9198783 - 000 Watts Bar WBNIC11 SG Inspection 180-Day Report Page 1 of 16

A 20004-019 (11/20/2012)

Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report Safety Related? [; YES F-1 NO Does this document establish design or technical requirements? 1 YES [7 NO Does this document contain assumptions requiring verification? YES IX] NO Does this document contain Customer Required Format? YES NO Signature Block Pages/Sections Name and P/LP, R/LR, Prepared/Reviewed/

Title/Discipline Signature A-CRF, A Date Approved or Comments Victor Newman P All Principal Engineer David C. Ingram R All Technical Consultant 2) 4 * '47,3 James P. Campbell /1 ,* AI A All Technical Manager, .

C&S Engineering Note: P/LP designates Preparer (P), Lead Preparer (LP)

R/LR designates Reviewer (R), Lead Reviewer (LR)

A-CRF designates Project Manager Approver of Customer Requested Format (A-CRF)

A designates Approver/RTM - Verification of Reviewer Independence Page 2

A 20004-019 (11/20/2012)

Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report Record of Revision Revision Pages/Sections/

No. Paragraphs Changed Brief Description / Change Authorization 000 All Original Release 4 I-Page 3

A Document No.: 51-9198783-000 AR EVA Watts Bar WBN1C11 SG Inspection 180-Day Report Table of Contents Page SIG NATURE BLOCK ............................................................................................................................. 2 RECO RD O F REVISIO N ....................................................................................................................... 3 LIST O F TABLES .................................................................................................................................. 5 LIST O F FIG URES ................................................................................................................................ 5 1.0 INTRO DUCTIO N ........................................................................................................................ 6 2.0 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT ........................................... 8

3.0 REFERENCES

......................................................................................................................... 16 Page 4

A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report List of Tables Page TABLE 2-1: EDDY CURRENT INSPECTION SCOPE ...................................................................... 8 TABLE 2-2: NUMBER OF INDICATIONS DETECTED FOR EACH DEGRADATION MECHANISM... 10 TABLE 2-3: NDE TECHNIQUES USED FOR EACH DEGRADATION MECHANISM ...................... 11 TABLE 2-4: SERVICE-INDUCED INDICATIO NS ............................................................................. 12 TABLE 2-5: NUMBER OF TUBES PLUGGED FOR EACH DEGRADATION MECHANISM ............... 15 TABLE 2-6: TOTAL NUMBER AND PERCENTAGE OF TUBES PLUGGED TO DATE .................. 15 List of Figures Page FIGURE 1-1: TUBE SUPPORT ARRANGEMENT FOR WATTS BAR-1 STEAM GENERATORS ........ 7 Page 5

A Document No.: 51-9198783-000 AR EVA Watts Bar WBNlC11 SG Inspection 180-Day Report

1.0 INTRODUCTION

During the Watts Bar Unit 1 (WBN1) Fall 2012 refueling outage (designated as 1C1I), inspections of all four WBN1 steam generators (SGs) were performed. These inspections included eddy current inspections of the SG tubing as well as primary and secondary side visual inspections. This report documents the "Watts Bar lCl 1 SG Inspection 180-Day Report" as required by the WBN1 Technical Specifications.

Commercial operation of the original steam generators began in 1996. Operation of the replacement steam generators (RSG) Westinghouse/Model 68AXP SG design began following the Unit 1 Cycle 7 refueling outage in 2006 when the SGs were replaced. The steam generators operated 1.184 EFPY in their first cycle after replacement which was the end of Cycle 8. An ISI (the first) was performed during that refueling outage. Cycle 11 is the second ISI of the replacement SGs (No inspections were performed in Cycles 9 or 10). The steam generators have operated a total of 5.254 EFPY since their replacement in the fall of 2006. They have operated 4.070 EFPY since the previous ISI.

Figure 1-1 below provides the arrangement of the tube support structures for the WBN1 SGs.

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A Document No.: 51-9198783-000 ARE VA Watts Bar WBN1C11 SG Inspection 180-Day Report Figure 1-1: Tube Support Arrangement for Watts Bar-1 Steam Generators All U-Bend Support Straps are 2" Wide

• TWO-PHASE EXIT REGION CROSS FLOW Tube Supports are fomaed by 2" and V" Lattice Bars AXIAL

- COLD SIDE RECIRCULATING ENTRANCE CROSS FLOW FEEDWATER ENTRANCE HOT SIDE CROSS FLOW RECIRCULATING ENTRANCE CROSS FLOW -

Note: VS = Vertical Strap, DS = Diagonal Strap Horizontal supports are a lattice grid design (ATSG)

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A Document No.: 51-9198783-000 AR EVA Watts Bar WBNlC11 SG Inspection 180-Day Report 2.0 180-DAY STEAM GENERATOR TUBE INSPECTION REPORT In accordance with WBN1 Technical Specification 5.7.2.12, "Steam Generator Program", and Technical Specification 5.9.9, "Steam Generator Tube Inspection Report", this report documents the scope and results of the 1C 11 SG inspections.

There are eight specific reporting requirements (labeled "a" through "h" below). Each reporting requirement is followed with the required information based on the inspections performed during the 1C1 1 outage.

a. The Scope of the Inspections Performed on Each SG The 1C 11 outage bobbin coil inspection was initially planned for 52.6% of the in-service tubes. The bobbin inspection included all tubes with prior indications of degradation. Subsequent scope expansions to bound wear and foreign objects resulted in a final inspection of 57.8% of in-service tubes.

In addition to the bobbin coil inspections, 5186 array coil inspections were also performed. The array coil exams were aimed at detection of foreign objects and foreign object wear near the top of the tubesheet and support wear up to the C06 cold leg support (see Figure 1-1). Expansions were conducted to encompass wear and loose parts. Expansions in some areas were performed with array probe to have the benefit of enhanced PLP detection.

Table 2-1: Eddy Current Inspection Scope BOBBIN S/G Exam SIG E Tests Analyzed Planned Expanded and Completed 1-1 Full Length rows 5+ 2577 247 2824 H/L candycane rows 1-4 132 0 132 C/L straight rows 1-4 132 0 132 1-2 Full Length rows 5+ 2637 305 2942 H/L candycane rows 1-4 132 0 132 C/L straight rows 1-4 132 74 206 1-3 Full Length rows 5+ 2522 259 2781 H/L candycane rows 1-4 132 0 132 C/L straight rows 1-4 132 0 132 1-4 Full Length rows 5+ 2538 237 2775 H/L candycane rows 1-4 132 0 132 C/L straight rows 1-4 132 7 139 TOTAL 11330 1129 12459 Page 8

A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C1 1 SG Inspection 180-Day Report Table 2-1: Eddy Current Inspection Scope (continued)

Array Top of Tubesheet S/G Planned Expanded Tests Analyzed Exams Exams and Completed 1-1 HL = H01-HTE 607 0 607 CL = C01-CTE/C08-CTE 607 44 651 1-2 HL = H01-HTE 607 0 607 CL = C01-CTE/C08-CTE/

VS2-CTE 607 51 658 1-3 HL = H01-HTE 605 0 605 CL = C01-CTE/C08-CTE 605 48 653 1-4 HL = H01-HTE 608 0 608 CL = C01-CTE/C08-CTE 608 189 797 TOTAL 4854 332 5186

+Point Special Interest and historical preplan RPC S/G Locations to Tests Analyzed Inspect and Completed 1-1 Hot Leg SI 54 54 Cold Leg SI 1 1 U-bend Si 4 4 1-2 Hot Leg Sl 17 17 Cold Leg SI 3 3 U-Bend SI 5 5 1-3 Hot Leg SI 12 12 Cold Leg Sl 6 6 U-Bend SI 1 1 1-4 Hot Leg SI 10 10 Cold Leg SI 5 5 U-Bend SI 0 0 TOTAL 118 118 All Sco es Summary S/G Tests Analyzed and Completed 1-1 4405 1-2 4570 1-3 4322 1-4 4466 TOTAL 17763 Visual Inspection Results In addition to the eddy current inspections, visual inspections were also performed on both the primary and secondary sides. Primary side inspections included all previously installed plugs, the bowl cladding, and the divider plate. The plug inspections showed no anomalies indicative of improper installation or in-Page 9

A Document No.: 51-9198783-000 AR EVA Watts Bar WBN1C11 SG Inspection 180-Day Report service degradation. The inspections of the bowl cladding and the divider plate showed no visual evidence of degradation of the cladding, divider plate, or divider plate welds.

Secondary side visual inspections were performed on the steam drums in SGs 12 and 13 to investigate the structural integrity of the steam drum components. There were no anomalies reported in either steam drum. The visual to the extent possible included the perforated riser pipes, steam dryers, drains, drain cups, auxiliary feed water nozzle and sprayers, transmitter penetrations, hardware screws and nuts between the separators, upper dryers, and the Marmon clamp. All components were covered evenly with 1/16" of magnetite. Steam drum inspections in SGs 11 and 14 were not inspected due to schedule and ALARA considerations.

Secondary side visual inspections were also performed at the top of the tubesheet in all SGs for the detection of foreign objects and for determining the effectiveness of water lancing. The cleanliness inspection at the top of the tubesheet resulted in additional sludge lancing. In bundle visuals were also performed by inserting the probe down several columns in each SG.

SG 4 was the only SG where foreign material was identified on the tubesheet. There were three pieces of wire identified. The pieces of wire appeared 3 3 to be TIG wire. One retrieved from the cold leg annulus not identified by eddy current was 3%" x /64". Another piece retrieved, identified by eddy current, was 2%" x 3/64". Per analysis guidelines, once the foreign object was removed and the signal was confirmed to no longer be present, the PLP records (it was seen on two adjacent tubes) were permanently removed from the ECT database. The third piece, not identified by eddy current, was 3" x /64". It could not be retrieved after two attempts. It appeared to be held in place due to the smaller gap between the tube and a stay rod (stay rods have a larger diameter than the tubes). The inability to retrieve the loose part resulted in the affected tubes bounding the loose part being plugged and stabilized. The PLP identification and disposition for tube plugging and stabilization is documented in AREVA CR 2012-7370.

One other indication in SG 4 identified by eddy current was examined visually. There was no appearance of a loose part. It was removed from the database.

The feedwater distribution boxes in each SG were inspected for the presence of foreign objects. These boxes have 0.29" diameter holes that serve to restrict foreign material of subsequent size from entering the steam generators. A number of foreign objects were removed from the boxes. SG 4 had the largest amount of material where 35 small objects were removed. Some of the objects appeared to be Furmanite.

PLP indications were recorded in SG 14 tubes 1-60, 1-62, and 1-64 but were attributed to the presence of water lancing equipment in the SG at the time of the ECT exam.

b. Active Degradation Mechanisms Found Volumetric wear was the only degradation mechanism detected during the 1Cl1 inspection. All of the wear indications detected were located at support structures either in the U-bend at vertical or diagonal straps or in the lattice structure of the Advanced Tube Support Grids (ATSG). No wear indications attributable to foreign objects were reported. Table 2-2 below shows the number of indications reported during the lCl 1 inspection.

Table 2-2: Number of Indications Detected for Each Degradation Mechanism Page 10

A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report Location of Wear SG 11 SG12 SG13 SG14 Total Indication Tubes Ind Tubes Ind Tubes Ind Tubes Ind Tubes Ind U-bend support 0 0 2 3 3 3 2 2 7 8 Detected Tube Support Grid 6 6 13 20 14 19 18 27 51 72 U-bend support 0 0 0 0 0 0 0 0 0 0 Plugged Tube Support Grid 1 1 3 6 4 9 6 15 14 31 0 0 2 3 3 3 2 2 7 8 Returnedto U-bend support Service Tube Support Grid 5 5 10 14 10 10 12 12 37 41 Note: All tubes with a wear indication of 15% or greater were plugged. Some of the tubes had multiple indications of wear which varied in size (see Table 2-4). All pluggable degradation was related to cold leg support wear.

c. Nondestructive Examination (NDE) Techniques Used for Each Degradation Mechanism Table 2-3 below provides the NDE techniques that were used for the detection of each degradation mechanism that was considered as existing or potential for the 1C1 1 inspection.

Table 2-3: NDE Techniques Used for Each Degradation Mechanism Degradation Mechanism Detection Technique U-Bend / Vertical Strap Wear Bobbin Horizontal / Tube Support Grid Wear Bobbin Tube-to-Tube Wear Bobbin Foreign Object Wear Bobbin / Array In addition to the detection techniques shown in the above table, +PointTM probes were also used for confirmation, characterization, and length sizing of wear indications at the vertical straps and horizontal grid supports.

d. Location, Orientation (if Linear), and Measured Sizes (if Available) of Service Induced Indications Table 2-4 below provides a listing of all service-induced indications reported during the 1 C11 inspection including the estimated depths from the bobbin coil. If length sizing was available, this information is also provided as reported from the +PointTm inspections.

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A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C1 1 SG Inspection 180-Day Report Table 2-4: Service-Induced Indications SG ROW COL IND %TW LOCATION Inch VOLTS Circ extent Ax extent Characterization Disposition 11 7 92 TWD 9 C04 0.93 0.31 ATSG Wear 11 9 104 TWD 12 H07 -0.87 0.39 ATSG Wear 11 29 124 TWD 13 C06 0.77 0.44 ATSG Wear 11 37 122 TWD 26 C05 0.84 1.26 0.53 0.54 ATSGWear Plugged 11 89 96 TWD 11 C03 -0.92 0.35 ATSG Wear 11 105 64 TWD 11 C05 -0.88 0.36 ATSG Wear 12 22 123 TWD 9 C03 0.84 0.3 ATSG Wear 12 24 123 TWD 11 C03 0.84 0.39 ATSG Wear Plugged 12 24 123 TWD 17 C07 -0.88 0.72 ATSG Wear Plugged 12 28 119 TWD 8 C06 -0.82 0.26 ATSG Wear 12 30 123 TWD 12 C05 -0.89 0.38 ATSG Wear 12 30 123 TWD 8 C06 -0.84 0.23 ATSG Wear 12 30 123 TWD 14 C06 0.84 0.48 ATSG Wear 12 30 123 TWD 13 C07 -0.86 0.44 ATSG Wear 12 31 122 TWD 24 C06 -0.82 1.15 0.28 0.45 ATSGWear Plugged 12 31 122 TWD 25 C07 -0.85 1.18 0.15 0.24 ATSG Wear Plugged 12 31 122 TWD 11 C08 -0.83 0.4 ATSG Wear Plugged 12 62 113 TWD 12 C07 -0.99 0.37 ATSG Wear 12 85 100 TWD 8 C06 -0.88 0.28 ATSG Wear 12 87 98 TWD 10 C03 -0.87 0.28 ATSG Wear 12 87 98 TWD 13 C06 -0.88 0.41 ATSG Wear 12 88 95 TWD 14 C03 -1.01 0.49 ATSG Wear 12 89 94 TWD 8 C03 -0.93 0.21 ATSG Wear 12 90 93 TWD 28 C06 -0.98 1.21 0.28 0.45 ATSGWear Plugged U Bend Support 12 91 58 TWD 8 VS2 0.8 0.22 Wear 12 91 94 TWD 8 C03 -0.89 0.22 ATSG Wear U Bend Support 12 100 63 TWD 12 VS2 -0.75 0.37 Wear U Bend Support 12 100 63 TWD 7 VS2 0.55 0.2 Wear 12 105 66 TWD 9 C03 0.84 0.27 ATSGWear 13 15 4 TWD 8 C06 -0.9 0.22 ATSGWear 13 19 2 TWD 11 C04 -0.86 0.38 ATSG Wear 13 23 124 TWD 12 C06 0.88 0.46 ATSG Wear 13 61 114 TWD 5 C06 0.82 0.21 ATSG Wear 13 86 29 TWD 21 C03 -0.95 0.77 0.61 0.53 ATSG Wear Plugged 13 86 29 TWD 9 C03 0.81 0.24 ATSG Wear Plugged Page 12

A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report Table 2-4: Service-Induced Indications SG ROW COL IND %TW LOCATION Inch VOLTS Circ extent Ax extent Characterization Disposition 13 86 97 TWD 12 C02 -0.83 0.48 ATSG Wear 13 86 99 TWD 8 C04 0.89 0.29 ATSG Wear 13 87 96 TWD 24 C03 -0.87 1.11 0.49 0.49 ATSG Wear Plugged 13 87 98 TWD 26 C02 -0.82 1.41 0.54 0.56 ATSG Wear Plugged 13 87 98 TWD 18 C04 -0.87 0.8 ATSG Wear Plugged 13 87 98 TWD 17 C04 0.79 0.73 ATSG Wear Plugged 13 87 98 TWD 26 C05 0.79 1.4 0.56 0.58 ATSG Wear Plugged 13 88 95 TWD 21 C03 -0.77 0.64 0.49 0.53 ATSG Wear Plugged 13 88 95 TWD 32 C03 0.84 1.48 0.51 0.5 ATSGWear Plugged 13 89 96 TWD 8 C03 -0.82 0.28 ATSG Wear 13 92 35 TWD 10 C03 -0.95 0.3 ATSG Wear 13 92 91 TWD 8 C05 -0.96 0.17 ATSG Wear 13 97 42 TWD 9 C04 0.78 0.34 ATSG Wear U Bend Support 13 98 71 TWD 9 VS4 0.82 0.22 Wear U Bend Support 13 100 55 TWD 8 VS2 -0.85 0.29 Wear U Bend Support 13 101 58 TWD 12 DS2 -0.86 0.4 Wear 14 13 78 TWD 11 C10 0.72 0.39 ATSGWear 14 23 124 TWD 11 C06 -0.82 0.38 ATSG Wear 14 27 124 TWD 11 C03 -0.85 0.38 ATSG Wear 14 35 122 TWD 9 C03 0.9 0.3 ATSG Wear 14 49 110 TWD 8 C12 -0.91 0.25 ATSG Wear 14 53 118 TWD 8 C02 -0.8 0.26 ATSG Wear 14 63 114 TWD 11 C06 -0.98 0.4 ATSG Wear 14 84 99 TWD 18 C03 0.82 0.74 ATSG Wear Plugged 14 85 100 TWD 8 C04 -0.84 0.26 ATSG Wear 14 86 99 TWD 25 C04 -0.98 1.24 0.48 0.51 ATSG Wear Plugged 14 86 99 TWD 10 C06 -0.94 0.35 ATSG Wear Plugged 14 89 96 TWD 10 C03 -0.84 0.31 ATSG Wear 14 90 95 TWD 14 C03 0.68 0.52 ATSG Wear Plugged 14 90 95 TWD 10 C04 -0.95 0.33 ATSG Wear Plugged 14 90 95 TWD 28 C06 -0.94 1.56 0.68 0.54 ATSGWear Plugged 14 90 95 TWD 8 C06 0.81 0.26 ATSG Wear Plugged 14 90 95 TWD 8 C08 -1.07 0.28 ATSG Wear Plugged 14 91 94 TWD 9 C03 0.82 0.31 ATSG Wear 14 92 35 TWD 19 C03 -1.06 0.8 ATSG Wear Plugged U Bend Support 14 92 81 TWD 8 VS2 0.9 0.3 Wear Page 13

A Document No.: 51-9198783-000 AREVA Watts Bar WBNlCI1 SG Inspection 180-Day Report Table 2-4: Service-Induced Indications SG ROW COL IND %TW LOCATION Inch VOLTS Circ extent Ax extent Characterization Disposition 14 93 36 TWD 11 C05 0.85 0.35 ATSG Wear U Bend Support 14 93 70 TWD 10 VS2 0.88 0.29 Wear 14 97 40 TWD 15 C03 -0.84 0.56 ATSG Wear Plugged 14 97 40 TWD 8 C04 0.85 0.26 ATSG Wear Plugged 14 97 40 TWD 9 C05 0.82 0.27 ATSG Wear Plugged 14 97 40 TWD 8 C06 -0.82 0.26 ATSG Wear Plugged 14 97 86 TWD 9 C03 0.85 0.39 ATSG Wear 14 100 45 TWD 10 C03 -0.95 0.35 ATSG Wear Plugged 14 100 45 TWD 19 C05 -0.96 0.78 ATSG Wear Plugged Page 14

A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C1 1 SG Inspection 180-Day Report

e. Number of Tubes Plugged During the Inspection Outage for Each Active Degradation Mechanism Table 2-5 below provides the numbers of tubes plugged for each degradation mechanism detected.

Table 2-5: Number of Tubes Plugged for Each Degradation Mechanism ATSG Wear Foreign Total SG (preventative) Object 11 1 0 1 12 3 0 3 13 4 0 4 14 6 *6 12

• No tube degradation was identified with the foreign object. Tubes were plugged and stabilized to bound the loose part.

f. Total Number and Percentage of Tubes Plugged to Date Table 2-6: Total Number and Percentage of Tubes Plugged to Date Inspection SG 11 SG 12 SG 13 SG 14 Total Prior to service 0 1 0 1 2 1C8 2008 2 1 3 1 7 ICI 2012 1 3 4 12 20 Total 3 5 7 14 29 Percent 0.06% 0.1% 0.14% 0.27% 0.14%

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A Document No.: 51-9198783-000 AREVA Watts Bar WBN1C11 SG Inspection 180-Day Report

g. The Results of Condition Monitoring, Including the Results of Tube Pulls and In-Situ Testing Tube Inteqrity As required by the WBN1 Steam Generator Program, a condition monitoring (CM) assessment was performed [1]. The only tube degradation detected during the IC1 1 inspection was wear at support structures (U bend supports and ATSGs). The deepest indication had an estimated depth of 32%TW from the bobbin coil exam. This indication was located at an ATSG. The maximum NDE length of any ATSG wear flaw was 0.68". The CM limit for a flaw of this length is approximately 55% TWD. This CM limit includes uncertainties for material properties, NDE depth sizing, and the burst pressure relationship.

Since the deepest flaw has an NDE depth less than the CM limit, the structural integrity performance criterion was met for the operating period prior to 1Cl .

Since wear indications will leak and burst at essentially the same pressure, accident-induced leakage integrity at a much lower accident pressure differential is also demonstrated. Operational leakage integrity was demonstrated by the absence of any detectable primary-to-secondary leakage during the operating period prior to 1C 1.

Since tube integrity was demonstrated analytically, in-situ pressure testing was not required nor performed during the 1Ci I outage. Likewise, no tube pulls were planned nor performed during 1C11.

h. The Effective Plugging Percentage for All Plugging in Each SG There are no sleeves installed in the WBN1 SGs. Therefore, the effective plugging percentage is the same as the plugging percentage shown in Table 2-6.

3.0 REFERENCES

1. AREVA Document 51-9196412-000 "Watts Bar Unit 1 Condition Monitoring for ICI I and Final Operational Assessment for Cycles 12, 13, and 14" Page 16