ML12321A047
| ML12321A047 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/30/2012 |
| From: | Lane N Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-640 | |
| Download: ML12321A047 (13) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 October 30, 2012 United States Nuclear Regulatory Commission Serial No.12-640 Attention: Document Control Desk SPS-LIC/CGL R1 Washington, DC 20555-0001 Docket No.
50-280 License No.
DPR-32 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT I STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR THE SPRING 2012 REFUELING OUTAGE Technical Specification 6.6.A.3 for Surry Power Station Units 1 and 2 requires the submittal of a Steam Generator Tube Inspection Report to the NRC within 180 days after Tavg exceeds 200°F following completion of an inspection performed in accordance with Technical Specification 6.4.Q, Steam Generator Program. Attached is the Surry Unit 1 report for the Spring 2012 refueling outage.
If you have any questions concerning this information, please contact Mrs. Candee G. Lovett at (757) 365-2178.
Very truly yours, N. L. Lane Site Vice President Surry Power Station
Attachment:
Surry Unit 1 Steam Generator Tube Inspection Report for the Spring 2012 Refueling Outage Commitments made in this letter: None
Serial No.: 12-640 Docket No.: 50-280 Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Avenue NE Suite 1200 Atlanta, Georgia 30303-1257 Ms. K. R. Cotton NRC Project Manager - Surry U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852-2738 Dr. V. Sreenivas NRC Project Manager - North Anna U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852-2738 NRC Senior Resident Inspector Surry Power Station Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station
Serial No.: 12-640 Docket No.: 50-280 ATTACHMENT SURRY UNIT I STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2012 REFUELING OUTAGE VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial No.: 12-640 Docket No.: 50-280 Page 1 of 10 SURRY UNIT I STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2012 REFUELING OUTAGE The following satisfies the requirement in TS 6.6.A.3.
generator (SG) inspections in Surry Power Station Technical Specification (TS) reporting During the Surry Unit 1 Spring 2012 refueling outage, steam accordance with TS 6.4.Q were completed for all three SGs.
This was the first inspection in the 4th inspection period which has a duration of 60 Effective Full Power Months (EFPM).
Surry Unit 1 exceeded 200°F on June, 2 2012; therefore, this report is required to be submitted by November 29, 2012. The SGs had operated for 300.1 EFPM at the time of this inspection.
Bold italicized text represents TS verbiage. The required information is provided under each reporting requirement as follows:
A report shall be submitted within 180 days after Tavg exceeds 200°F following completion of an inspection performed in accordance with the Specification 6.4.Q, "Steam Generator (SG) Program." The report shall include:
- a. The scope of inspections performed on each SG The planned eddy current examination scope is identified below in Table 1. The only scope expansions required were those necessary to bound foreign objects and foreign object related degradation, as well as to resolve ambiguous indications.
A complete summary of the tube examinations performed during the outage is provided in the final inspection status (Table 2).
The primary side inspections activities also included a video/visual examination of all six channel heads (as-found/as-left, specifically including all plugs, the divider plate weld region, and the bottom of the bowl per NSAL-12-1 with the bowl dry).
No anomalous conditions associated with these inspections were found.
Table 1 - Primary Side Examination Scope Scope SG A SG B SG C Bobbin Probe: Full Length (except row 1 and 2 U-bends) 100%
100%
Array Probe: H/L Tubesheet and Expansion Transition 100%
36%
100%
Array Probe: C/L Tubesheet and Expansion Transition 37%
36%
Plus Point Probe: Row 1 and 2 U-bends (07C to 07H) 100%
100%
Serial No.: 12-640 Docket No.: 50-280 Page 2 of 10 Table 2 - EO0C24 Actual ECT Examination ScoDe SG A SG B SG C Scope Description Extent Acquired Acquired Acquired B~obbin Cil Exams Full Length TEHTEC 3023 3031 C/L Straight (Row 1-2) 7HTEC 181 275 H/L Straight (Row 1-3) 7CTEC 264 181 H/L Candycane (Row 3) 7HTEH 10 94 Restricted Tube TEHTEC 1
(R5C35)
C/L Candycane (Row 3) 7HTEC 83 Array Exams~
~
H/L Array (Non-Baffle TSH1H 835 266 837 Plate)
H/L Array (Baffle Plate)
TSHBPH 2463 931 2469 C/L Array (Non-Baffle TSC1C 295 282 Plate)
C/L Array (Baffle Plate)
TSCBPC 933 924 C/L Array (Bounding)
Various 2
MRPC Exams
~~777 U-bend +PT (Row 1-2) 7H7C 181 181 Select Tube +PT Various 33 12 68 MRRC Special Interest H/L Previous Various 17 10 10 Indications H/L Previous DNT>2V Various 167 130 H/L Indications Various 45 1
40 U-bend Previous Various 2
3 DNT>2V U-bend Indications Various 14 3
C/L Previous Various 3
1 Indications C/L Previous DNT>2V Various 3
2 C/L Indications Various 33 10 Total 8588 1220 8541
Serial No.: 12-640 Docket No.: 50-280 Page 3 of 10 The following Secondary side exams were conducted:
SGs A, B, and C:
Post-lancing visual examination of the top-of-tubesheet annulus and no-tube lane.
Visual examination of historical foreign object-related locations.
Visual investigation of any accessible locations having eddy current indications potentially related to foreign objects and removal of retrievable foreign objects.
SG A:
Visual examination, from the steam drum in SG A, of all accessible steam drum components and structures, including the feedring exterior, the upper tube bundle, and 7 th TSP via probe drops through the primary moisture separators. No adverse conditions were noted during this inspection.
- b. Active degradation mechanisms found Degradation mechanisms targeted by the inspection plan included anti-vibration bar (AVB) wear, pitting, foreign object wear, tube support wear, and stress corrosion cracking (SCC) at various locations within the steam generator tube bundle. AVB wear, foreign object wear, tube support plate wear, one legacy pit indication, and one legacy sludge lance wear flaw were detected. No SCC was detected.
A permanent alternate repair criteria (ARC) was incorporated into the Surry Technical Specifications, effective during the EOC24 outage.
The ARC specifies that tubes with service-induced flaws located greater than 17.89 inches below the top of the tubesheet do not require plugging. Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 17.89 inches below the top of the tubesheet shall be plugged upon detection.
- c. Nondestructive examination techniques utilized for each degradation mechanism Inspections focused on the following degradation mechanisms listed in Table 3 utilizing the referenced eddy current techniques.
Serial No.: 12-640 Docket No.: 50-280 Page 4 of 10 Table 3 - Insoection Method for ADplicable Deqradation Modes Classification Degradation Location Probe Type Mechanism Existing Tube Wear Anti-Vibration Bobbin - Detection Bars Bobbin and +PointTM - Sizing Existing Tube Wear Tube Support Bobbin - Detection Plate Bobbin and +PointTM - Sizing Existing Tube Wear
- Freespan, Bobbin and Array - Detection (foreign TTS, FDB,
+PointTM - Sizing objects)
TSPs Existing ODSCC Hot Leg Top-Bobbin and Array - Detection of-Tubesheet
+PointTM - Sizing Sludge Pile Area Existing PWSCC At the Tube Inspection not required per ends PARC TE + 4 Inches Existing PWSCC Hot Leg Top-Array - Detection and Sizing of-Tubesheet Existing OD Pitting Top-of-Bobbin - Detection Tubesheet
+PointTM - Sizing Potential Tube Wear Flow Bobbin - Detection Distribution Bobbin and +PointTM - Sizing Baffle Potential ODSCC Freespan and Array - Detection Tube Supports
+PointTM - Sizing Potential PWSCC Hot Leg Within Array - Detection Tubesheet
+PointTM - Sizing Anomaly locations
Serial No.: 12-640 Docket No.: 50-280 Page 5 of 10
- d. Location, orientation (if linear), and measured sizes (if available) of service induced indications As stated in the (b) response above, several wear type indications were noted. Tables 4 and 5 provide the detailed information regarding these indications.
Table 4 - AVB Indications Depth (%TW)
AVB (ETSS 96004.1)
SG Row Col No.
2009 2012 SGA 9
54 AV1 11 11 SGA 12 45 AV2 11 11 SGA 12 47 AV4 14 13 SGA 30 57 AV2 16 15 SGA 32 48 AV3 15 14 SGA 32 65 AV2 14 11 SGA 32 66 AV2 11 SGA 32 69 AV2 22 22 SGA 32 69 AV3 17 15 SGA 32 69 AV4 19 19 SGA 33 16 AV2 11 12 SGA 33 63 AV3 20 20 SGA 33 63 AV4 14 15 SGA 33 66 AVI 10 12 SGA 33 66 AV2 12 15 SGA 34 59 AV2 14 11 SGA 35 17 AV2 10 SGA 35 78 AV2 12 14 SGA 36 47 AV1 11 SGA 36 75 AV2 14 15 SGA 36 76 AV2 12 10 SGA 37 75 AV2 12 11 SGA 38 62 AV4 10 10 SGA 39 42 AV1 11 12 SGA 39 71 AV4 11 10 SGA 39 72 AV4 14 15 SGA 40 42 AV1 13 14 SGA 40 69 AV4 11 13 SGA 46 43 AVI 11 12 SGA 46 44 AV1 13 13 SGA 46 45 AV1 14 15 SGA 46 45 AV4 10 10
Serial No.: 12-640 Docket No.: 50-280 Page 6 of 10 Table 4 - AVB Indications (continued)
Depth (%TW)
AVB (ETSS 96004.1)
SG Row Col No.
2009 2012 SGC 24 33 AV2 10 SGC 27 10 AV3 11 12 SGC 33 16 AV2 11 SGC 35 17 AV1 20 25 SGC 35 17 AV4 10 11 SGC 35 46 AV2 12 SGC 35 46 AV3 14 15 SGC 38 67 AV3 16 24 SGC 39 23 AV1 16 18 SGC 39 23 AV2 18 20 SGC 39 23 AV3 22 26 SGC 39 69 AV3 15 15 SGC 42 31 AVI 19 23 SGC 42 31 AV2 19 23 SGC 42 31 AV3 16 19 SGC 42 31 AV4 13 15 SGC 44 47 AV3 11 10 SGC 45 38 AV3 10 10 SGC 45 40 AV4 13 12 SGC 45 58 AV4 11 10 Not reported during that outage.
Serial No.: 12-640 Docket No.: 50-280 Page 7 of 10 Table 5 - Summary of Non-AVB-Wear Volumetric Degradation Axial Foreign Max Depth Length Circ. Length Initially Signal Present Prior to Object In-Situ Plugged &
SG Row Col ILocatiIaon ETSS (TW)
(in) in Reported Current Outage?
Cause Remaining?
Tested?
Stabilized?
A 2
57 06C-0.39" 96910.1 19 0.29 0.37 2006 Yes. No change since TSP n/a No No initially reported.
Wear A
3 66 05C-0.78" 27901.1 26 0.30 0.45 2009 Yes. No change since Foreign No No No initially reported.
Object A
6 88 TSH+0.28" 27901.1 25 0.30 0.40 2006 Yes. No change since Foreign No No No initially reported.
Object A
8 38 TSH+0.45" 21998.1 21 0.27 0.35 2001 Yes. No change since Legacy No No No initially reported.
Pitting A
34 67 TSH+0.01" 27901.1 24 0.27 0.37 2006 Yes. No change since Foreign No No No initially reported.
Object A
38 30 TSC+1.78" 27901.1 19 0.33 0.42 2006 Yes. No change since Foreign No No No initially reported.
Object B
1 7
TSH+0.26" 21998.1 20 0.70 0.29 2007 Yes. No change since Historical n/a No No B_
1_______ 7 21998.1_
20 0.70 0.29 2007initially reported.
SG Maint-
-__NoNo B
31 15 BPH+0.55" 27901.1 19 0.32 0.35 2010 Yes. No change since Foreign No No No initially reported.
Object B
31 16 BPH+0.58" 27901.1 22 0.27 0.40 2010 Yes. No change since Foreign No No No initially reported.
Object B
32 15 BPH+0.50" 27901.1 18 0.24 0.35 2010 Yes. No change since Foreign No No No I
initially reported.
Object B
32 18 BPH+0.59" 27901.1 19 0.24 0.38 2010 Yes. No change since Foreign No No No initially reported.
Object B
33 18 BPH+0.58" 27901.1 21 0.29 0.46 2010 Yes. No change since Foreign No No No I
initially reported.
Object B
35 20 BPH+1.10" 27902.1 17 0.51 0.43 2010 Yes. No change since Foreign No No No I
initially reported.
Object B
40 50 TSH+0.24" 27901.1 31 0.32 0.48 2007 Yes. No change since Foreign No No No initially reported.
Object B
40 51 TSH+0.34" 27901.1 33 0.35 0.48 2007 Yes. No change since Foreign No No No initially reported.
Object B
41 51 TSH÷0.10" 27901.1 24 0.27 0.37 2007 Yes. No change since Foreign No No No 41_51___________27901.1_24_0.27 0.37_2007 initially reported.
Object NoNo C
27 82 BPH+0.58' 27901.1 27 0.32 0.49 2010 Yes (2000).
Foreign No No No C
27 82_
BPH+0.58" 27901.1 27 0.32 0.49 2010 No change since 2000.
Object No NoNo C
36 24 BPH-0.22" 96910.1 3
0.31 0.40 2012 Yes (2006).
TSP n/a No No Not present in 2000.
Wear C
36 64 TSC+0.04" 27901.1 30 0.29 0.40 2012 No relevant RPC exams Foreign No No No in history.
Object C
38 66 TSC+0.11" 27901.1 29 0.40 0.46 2009 Yes. No change since Foreign No No No I
I I
I initially reported.
Object I
I
Serial No.: 12-640 Attachment Docket No.: 50-280 Page 8 of 10
- e. Number of tubes plugged during the inspection outage for each active degradation mechanism No tubes required plugging as a result of SG inspections performed during the EOC24 outage.
- f. Total number and percentage of tubes plugged to date Table 6 provides the plugging totals and percentages to date.
Table 6 - Tube Plugging Summary Tubes Plugged To-Tubes Installed Dt Date SG A 3,342 44(1.3%)
SG B 3,342 26 (0.8%)
SG C 3,342 36(1.1%)
Total 10,026 106 (1.1%)
- g. The results of condition monitoring, including the results of tube pulls and in-situ testing The condition monitoring assessment of the EOC24/REOC19 structural and leakage integrity concluded that the Surry Unit 1 steam generators, as indicated by the results of the primary and secondary side inspections performed during this outage; satisfy required structural and leakage integrity criteria. Therefore, there was no need to pull tubes or in-situ test.
- h. The effective plugging percentage for all plugging in each SG Since none of the Surry Unit 1 SG tubes have been sleeved, the effective plugging percentage is identical to the plugging percentages provided in the response to (f).
- i. The primary to secondary LEAKAGE rate observed in each SG (if it is not practical to assign the LEAKAGE to an individual SG, the entire primary to secondary LEAKAGE should be conservatively assumed to be from one SG) during the cycle preceding the inspection which is the subject of the report During the cycle preceding the EOC24 outage, no measurable primary-to-secondary leakage
(>1 GPD) was observed in any Unit 1 SG.
Serial No.: 12-640 Attachment Docket No.: 50-280 Page 9 of 10
- j.
The calculated accident induced LEAKAGE rate from the portion of the tubes below 17.89 inches from the top of the tubesheet for the most limiting accident in the most limiting SG. In addition, if the calculated accident induced LEAKAGE rate from the most limiting accident is less than 1.80 times the maximum operational primary to secondary LEAKAGE rate, the report should describe how it was determined.
The permanent ARC requires that the component of operational leakage from the prior cycle from below the H-star distance be multiplied by a factor of 1.8 and added to the total accident leakage from any other source, and compared to the allowable accident induced leakage limit.
Since there is reasonable assurance that no tube degradation identified during this outage would have resulted in leakage during an accident, the contribution to accident leakage from other sources is zero. Assuming that the prior cycle operational leakage of <1 GPD originated from below the H-star distance, and multiplying this leakage by a factor of 1.80 as required by the permanent ARC, yields an accident induced leakage value of <1.80 GPD. This value is well below the 470 GPD limit for the limiting SG and provides reasonable assurance that the accident induced leakage performance criteria would not have been exceeded during a limiting design basis accident.
- k. The results of the monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided.
No indications of tube slippage were identified during the evaluation of bobbin probe examination data from SGs A or C. No bobbin probe examinations were performed in SG B during EOC24. All tubes in SG B were screened for slippage during EOC23 (no slippage was identified) and will again be screened during EOC25.
Serial No.: 12-640 Attachment Docket No.: 50-280 Page 10 of 10 Acronyms ARC Alternate Repair Criteria BPC Baffle Plate Cold BPH Baffle Plate Hot C/L Cold Leg DNT Dent EOC End of Cycle ETSS Eddy Current Technical Specification Sheet GPD Gallons Per Day H/L Hot Leg MRPC Motorized Rotating Pancake Coil OD Outside Diameter ODSCC Outside Diameter Stress Corrosion Cracking PWSCC Primary Water Stress Corrosion Cracking REOC Replacement End of Cycle RPC Rotating Pancake Coil (also a generic term for rotating probes of any kind)
TEC Tube End Cold Leg TEH Tube End Hot Leg TSC Top of Tubesheet Cold Leg TSH Top of Tubesheet Hot Leg TSP Tube Support Plate TW Through Wall