ML11291A058
| ML11291A058 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 10/05/2011 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 11-495 | |
| Download: ML11291A058 (14) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 October 5, 2011 United States Nuclear Regulatory Commission Serial No.11-495 Attention: Document Control Desk SPS-LIC/CGL RO Washington, DC 20555-0001 Docket No. 50-281 License No. DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 2 STEAM GENERATOR TUBE INSERVICE INSPECTION REPORT FOR THE 2011 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 2 report for the Spring 2011 refueling outage.
If you have any questions concerning this information, please contact Mrs. Candee G. Lovett at (757) 365-2178.
Very truly yours, G. T. Bischof Site Vice President Surry Power Station
Attachment:
Surry Unit 2 Steam Generator Tube Inspection Report for the Spring 2011 Refueling Outage Commitments made in this letter: None A0 fý-
Serial No.: 11-495 Docket No.: 50-281 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 Mr. R. E. Martin NRC Project Manager - North Anna U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G9A 11555 Rockville Pike Rockville, Maryland 20852 NRC Senior Resident Inspector Surry Power Station Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station
Serial No.: 11-495 Docket No.: 50-281 ATTACHMENT SURRY UNIT 2 STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2011 REFUELING OUTAGE VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 2 of 13 SURRY UNIT 2 STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2011 REFUELING OUTAGE The following satisfies the Surry Power Station Technical Specification (TS) reporting requirement section 6.6.A.3. During the Surry Unit 2 Spring 2011 (EOC23) refueling outage, Steam Generator (SG) inspections in accordance with TS 6.4.Q were completed for SGs "B" and "C".
The Unit 2 SGs were in the 4th inspection period which has a duration of 60 Effective Full Power Months (EFPM). The Spring 2011 outage was the first outage of the 4th period.
TS 6.6.A.3 requires a SG Tube Inspection Report to be submitted to the NRC within 180 days following the unit exceeding 200'F. Unit 2 initially exceeded 200°F on May 26, 2011; therefore this report is required to be submitted by November 22, 2011. At the time of this inspection, the current SGs had operated for 284.6 EFPM since the first inservice inspection.
For EOC23, an alternate tube repair criterion (ARC) was incorporated into the Surry TS to allow tubes with service-induced flaws located greater than 17.74 inches below the top of the tubesheet to not require plugging. Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 17.74 inches below the top of the tubesheet would be plugged upon detection.
In the discussion below bold italicized wording represents TS verbiage and the required information is provided directly below each reporting requirement. A list of acronyms is attached at the end of this report.
TS 6.6.A.3 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 reportshall include:
- a. The scope of inspections performed on each SG Primary Side 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 EOC23 outage is provided in the final inspection status (Table 2).
The primary side workscope also included a video / visual examination of four channel heads (as-found / as-left), specifically including all plugs, as well as the divider plate weld region. No anomalous conditions associated with the divider plate, previously installed plugs, or plugs installed during this outage were observed.
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 3 of 13 Secondary Side During the Surry Unit 2 EOC23 outage, secondary side visual examinations were performed at the top of the tubesheet in SGs "B" and "C" and at selected flow distribution baffle plate locations in SG "C." No adverse conditions were noted during these inspections. As a preventive measure to address FAC historically observed in the feedrings, the feedrings in all
.three SGs were replaced with FAC-resistant stainless steel material. Foreign Object Search and Retrieval (FOSAR) examinations were performed in each SG at the top of the tubesheet, in the annulus, and no-tube lane.
Table I - EOC23 Planned ECT Examination Scope Scope SG A SG B SG C Bobbin probe:
100% Full Length n/a "
(except for row 1 and 2 ubends)
Rotating Probe:
58% H/L Expansion Transition n/a V" V/
(TSH+/-3")
Rotating Probe:
100% Tier 1 High Stress Tubes n/a V/
(TSH+3"/-1 8")
Rotating Probe: n/a 50% H/L Dents >_2 Volts Rotating Probe:
100% Row 1 and 2 U-bends n/a Y/
(7C to 7H)
Rotating Probe:
50% Five Tube Deep C/L Periphery n/a V/ v/
(TSC+/-3")
Rotating Probe:
50% H/L OXP Sample n/a vI (TSH+3"/-18")
Rotating Probe:
20 Largest Voltage C/L OXPs n/a / /
(TSC+3"/-1 8")
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 4 of 13 Table 2 - EOC23 Actual ECT Examination Scope (Final Inspection Status)
S/G A S/G B I S/G C Scope Description Extent Acquired Acquired Acquired Bobbin Coil Exams Full Length TEHTEC - 3044 3020 C/L CandyCane (Row 7HTEC - 94 94 3)
C/L Straight (Row 1-2) 7CTEC - 186 181 C/L Straight Restricted 7CTEC - - 1 H/L Straight (Row 1-3) 7HTEH - 280 276 MRPC Exams H/L Tubesheet TSH TSHTSH - 223 38
+3/-18 H/L Tubesheet TSH +/- TSHTSH - 1906 1939 3
H/L Tubesheet Previous TSHTSH - 4 19 Ind.
H/L Tubesheet TSHTSH - 14 15 Bounding C/L Tubesheet TSC TSCTSC - 20 20
+3/-18 C/L Tubesheet (TSC +/- TSCTSC - 525 525 3)
C/L Tubesheet Previous TSCTSC - 1 3 Ind.
C/L Tubesheet TSCTSC - 5 20 Bounding Ubend RPC (R 1-2) 7C7H - 186 182 Other RPC Various - 12 70 Special Interest H/L Pre Planned Various - 229 160 H/L Bobbin Indications Various - 14 50 C/L Pre Planned Various - 4 4 C/L Bobbin Indications Various - 4 9 Ubend Pre Planned Various - 1 -
Ubend Bobbin Various - 6 18 Indications I Total 6758 6644 Total 6758 6644
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 5 of 13
- b. Active degradationmechanisms found Degradation mechanisms targeted by the inspection plan included anti-vibration bar (AVB) wear, pitting, foreign object wear, tube support wear, as well as stress corrosion cracking (SCC) at various locations within the steam generator tube bundle. Only AVB wear, foreign object wear, and tube support plate wear were detected during the current outage. Lists of service induced indications are provided in Item d.
A Temporary Alternate Repair Criteria (ARC) was incorporated into the Surry Technical Specifications, effective during the EOC23 outage and during the operating cycle subsequent to the EOC23 outage. This ARC specifies that tubes with service-induced flaws located greater than 17.74 inches below the top of the tubesheet do not require plugging. Further, the ARC requires that tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 17.74 inches below the top of the tubesheet be plugged upon detection. No such degradation was identified during the current outage inspection.
- c. Nondestructive examination techniques utilized for each degradationmechanism The inspection program focused on the degradation mechanisms listed in Table 3 and utilized the referenced eddy current techniques.
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 6 of 13 TnhlA 3 - In~qnn*tinn Me~thnd fnr AnnlienhlADn Bnradation Mndr_*
Degradation Classification Mechanism Location Probe Type Existing Tube Wear Anti-Vibration Bars Bobbin - Detection and Sizing Bobbin and +Point M- Detection OD Pitting Top-of-Tubesheet M-Sizin TM+Point Existing
+Pointr - Sizing Bobbin TM- Detection
- Sizing Existing Tube Wear Tube Support Plate +Point Tube Wear Bobbin and +PointTM - Detection Existing (foreign objects) Freespan and T +PointTM- Sizing PtnilODSCC T Potential PWSCC Hot Leg Top-of-Tubesheet +PointM- Detection and Sizing Potential PWSCC Tube Ends N/A*
Bobbin - Detection Potential Tube Wear Flow Distribution Baffle +PointTM - Sizing Bulges, Dents, Manufacturing ODSCC Anomalies, and Above- +PoinTM - Detection and Sizing Potential PWSCC Tubesheet Overexpansions (OVR)
Tubesheet Crevice NTEs in +PointTM - Detection and Sizing Potential ODSCC Tubes With Potential Tube Slippage Within Tubesheet Bobbin Detection Tubesheet Tm Potential PWSCC Overexpansions (OXP) +Point - Detection and Sizing Potential ODSCC PWSCC Row 1 and 2 U-bends +PointTM - Detection and Sizing Bobbin -Detection Potential ODSCC Freespan and Tube Supports +PointTM - Sizing
- Inspection not required per technical specitication alternate repair criteria.
- d. Location, orientation (if linear), and measured sizes (if available) of service induced indications As stated in Item b above, service induced indications were identified. Tables 4 and 5 provide the required information.
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 7 of 13 Table 4 - AVB Indications Depth (%TW)
AVB (ETSS 96004.1)
SG Row Col No. 2008 2011 B 24 57 AV1 20 17 B 31 58 AV2 16 15 B 32 69 AV2 12 10 B 33 60 AV3 16 12 B 37 71 AV3 - 11 B 38 51 AV4 16 12 B 38 74 AV1 14 10 B 38 74 AV2 17 12 B 44 60 AV2 12 7 B 45 57 AV1 11 9 C 24 8 AV4 12 10 C 25 9 AV1 - 10 C 25 9 AV3 11 10 C 25 27 AV1 15 17 C 25 27 AV2 29 33 C 25 27 AV3 11 12 C 25 29 AV2 - 12 C 25 29 AV3 19 23 C 26 26 AV3 17 18 C 26 26 AV4 16 17 C 26 39 AV3 20 15 C 31 65 AV2 12 10 C 31 69 AV2 18 18 C 31 69 AV3 13 12 C 31 75 AV3 13 12 C 31 75 AV4 13 13 C 33 59 AV3 17 16 C 33 59 AV4 - 10 C 33 68 AV1 18 19 C 33 68 AV2 18 20 C 33 70 AV1 10 10 C 33 70 AV3 16 18 C 34 29 AV3 - 14 C 34 29 AV4 15 18 C 34 79 AV1 - 12 C 35 77 AV2 10 10 C 37 63 AV2 10 11 C 37 73 A\/3 15 15 C 37 75 AV3 - 12
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 8 of 13 Table 4 - AVB Indications (cont)
Depth (%TW)
AVB (ETSS 96004.1)
SG Row Col No. 2008 2011 C 38 28 AV1 10 11 C 38 28 AV3 15 15 C 38 30 AV2 - 15 C 38 43 AV3 15 11 C 38 73 A'/1 10 12 C 38 73 AV2 - 12 C 38 74 AV2 - 12 C 39 50 AV3 13 13 C 39 53 AV3 26 28 C 39 55 AV3 22 22 C 39 55 AV3 13 13 C 39 55 AV4 22 22 C 39 72 AV4 - 10 C 40 33 AV2 22 24 C 40 33 AV3 23 25 C 40 63 AV2 - 11 C 40 63 AV3 15 20 C 40 63 AV4 16 18 C 41 66 AV3 16 C 41 68 AV4 - 15 C 43 39 AV2 19 13 C 43 61 AV1 21 22 C 43 63 AV1 12 11 C 44 61 AV1 10 10 C 46 45 AV2 12 10 Not reported in 2008. Used % TW as default depth.
Notes:
ETSS 96004.1, Rev. 13 sizing parameters:
- 1) Total Random Sizing Uncertainty at 95/50: 13.3 %TW
- 2) Upper Bound 2011 Depth: [0.98] x [Field Call] + [2.89] + [13.3]
- 3) Fall 2014 Projected Depth: [Upper Bound 2011 Depth] + [(7.0%TW/Cycle) x 2 Cycles]
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 9 of 13 Table 5 - Summary of Non-AVB Volumetric Degradation Identified R Max Axial Circ. Signal Present Foreign o C Depth Length Length Initially Prior to Current Object w ol Location ETSS (%TW) (in) (in) Reported Outage? Cause Remaining?
B 23 82 TSH+0.01 27901.1 22 %TW 0.27 0.35 2003 Yes.change.
No signal Foreign No Object B 36 26 TSC+0.01 27905.1 26 %TW 0.33 0.40 2008 Yes. No signal Foreign No change. Object B 37 27 TSC+0.15 27901.1 23 %TW 0.29 0.42 2008 Yes.change.
No signal Foreign No Object 3C+0.52 96910.1 9 %TW 0.29 0.40 2011 Yes, in TSP c 3 72 1996 bobbin data. /a No RPC.
3C+0.49 96910.1 7 %TW 0.24 0.32 2011 C 28 71 TSH+0.28 27901.1 24 %TW 0.35 0.40 2009 Yes. No signal Foreign No change since 1996. Object C 32 36 BPH+0.60 27901.1 20 %TW 0.21 0.40 2009 Yes. No signal Foreign No change. Object 33 17 TSH+2.63 27901.1 21 %TW 0.4 0.42 2005 Yes. No signal Foreign No change. Object C 34 18 TSH+1.03 27901.1 22 %TW 0.35 0.42 2005 Yes. No signal Foreign No change. Object C 34 20 TSH+0.88 27901.1 27 %TW 0.3 0.45 2005 Yes. No signal Foreign No change. Object C 34 74 TSH+0.04 27901.1 29 %TW 0.43 0.45 2005 Yes. No signal Foreign No change. Object C 35 19 TSH+0.24 27901.1 29 %TV 0.32 0.48 2005 Yes. No signal Foreign No I I I change. Object 35 22 TSH+1.03 27901.1 30 %TW 0.36 0.45 2005 Yes. No signal Foreign No change. Object C 35 30 TSH+0.09 27901.1 36 %TW 0.33 0.40 2005 Yes. No signal Foreign No change. Object C 36 68 TSH+0.13 27902.1 26 %TW 0.51 0.45 2005 Yes. No signal Foreign No change, Object c 37 31 TSH-0.01 27901.1 27 %TW 0.30 0.45 2011 Yes, in 1996 3-coil Foreign No data. No change. Object c 37 32 TSH-0.03 27901.1 24 %TW 0.25 0.37 2011 Yes, in 2005 +Point Foreign No data. No change. Object C 37 33 TSH+0.04 27901.1 27 %TW 0.36 0.48 2011 Yes, data.inNo 1996 3-coil change. Foreign Object No C 37 34 TSH+0.02 27901.1 26 %TW 0.29 0.40 2009 Yes. No signal Foreign No change since 1996. Object C 37 35 BPH+0.55 27901.1 31 %TW 0.29 0.45 2005 Yes. No signal Foreign No change. Object
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 10 of 13 Table 5 - Summa of Non-AVB Volumetric Degradation Identified (cont)
R Max Axial Circ. Signal Present Foreign S 0 C Depth Length Length Initially Prior to Current Object G w ol Location ETSS (%TW) (in) (in) Reported Outage? Cause Remaining?
C 37 54 TSH+0.15 27901.1 24 %TW 0.33 0.42 2005 Yes. No signal change.
Foreign Object No 7C-0.58 96910.1 20 %TW 0.61 0.53 2005 37 c7 73 r 73signal I I Yes. Possible change.
TSP Wear n/a 7C-0.56 96910.1 9 %TW 0.4 0.42 2011 Yes, present in 2005 Foreign C 38 32 BPH+0.58 27901.1 24 %TW 0.26 0.29 2011 bobbin data. No Oreig No RPC. Object C 38 53 TSH+0.10 27901.1 23 %TW 0.27 0.40 2005 Yes. No signal Foreign No change. Object BPH+0.59 27901.1 22 %TW 0.25 0.34 2011 No Yes, present in 2005 Foreign C 39 32 bobbinRPC.
data. No Orect Object BPH+0.60 27901.1 25 %TW 0.32 0.42 2011 No Yes, present in 2005 oreign C 39 34 BPH+0.59 27901.1 25 %TW 0.27 0.42 2011 bobbin data. No Obet No RPC. bjc Yes, present in 2005 Foreign C 40 34 BPH+0.55 27901.1 21 %TW 0.24 0.29 2011 bobbin data. No Oreig No RPC.Object C 44 42 TSH+0.12 27901.1 23 %TW 0.32 0.42 2005 Yes. No signal change.
Foreign Object No C 44 43 TSH+0.15 27901.1 23 %TW 0.37 0.42 2005 Yes. No signal change.
Foreign Object No C 44 47 TSH+0.02 27901.1 27 %TW 0.35 0.45 2005 Yes. No signal Foreign No change. Object TSH+0.23 27901.1 22 %TW 0.33 0.42 TSH+0.29 27901.1 24 %TW 0.32 0.34 c 45 43 2005 Yes. No signal Foreign No change. Object TSH+0.71 27901.1 20 %TW 0.24 0.40 Overall Dimensions 0.64 0.85 C 45 47 TSH+0.21 27901.1 23 %TW 0.34 0.40 2005 Yes. No signal Foreign No change. Object
- e. Number of tubes plugged during the inspection outage for each active degradation mechanism No tubes were plugged during EOC23.
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 11 of 13
- 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 Tubes Installed To Date To Date SG "A" 3,342 30 (0.9%)
SG "B" 3,342 18 (0.5%)
SG "C" 3,342 46 (1.4%)
Total 10,026 94 (0.9%)
- g. The results of condition monitoring,including the results of tube pulls and in-situ testing None of the tube degradation identified in Surry Unit 2 SGs during the EOC23 outage violated the structural performance criteria, thereby providing reasonable assurance that none of these flaws would have leaked during a limiting design basis accident.
Based on the evaluations documented, degradation identified during the Spring 2011 inspection satisfied condition monitoring requirements for SG tube structural and leakage integrity.
Therefore, tube pulls and in-situ pressure testing were not necessary.
- h. The effective plugging percentagefor all plugging in each SG Since none of the Surry Unit 2 SG tubes have been sleeved, the effective plugging percentage is identical to the plugging percentages provided in Item f.
L ... for Unit 2 during Refueling Outage 23 and the subsequent operating cycle, the primary to secondary LEAKAGE rate observed in each SG ... during the cycle preceding the inspection which is the subject of the report During the cycle preceding EOC23, no measurable primary-to-secondary leakage (i.e., >1 GPD) was observed in any Unit 2 SG.
- j. ... for Unit 2 during Refueling Outage 23 and the subsequent operating cycle, the calculated accident induced LEAKAGE rate from the portion of the tubes below ...
17.74 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 2.03 times the maximum operationalprimary to secondary LEAKAGE rate, the report should describe how it was determined.
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 12 of 13 The Temporary ARC requires that the component of operational leakage from the prior cycle from below the H-star distance be multiplied by a factor of 2.03 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 2.03, yields an accident induced leakage value of <2.03 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. ... for Unit 2 during Refueling Outage 23 and the subsequent operating cycle, the results of the monitoring for tube axial displacement (slippage). If slippage is discovered,the implicationsof the discovery and corrective action shall be provided.
The Temporary ARC requires routine monitoring for tube slippage within the tubesheet and any tubes showing evidence of slippage require plugging. This condition could only occur if the tube severs circumferentially within the tubesheet, a condition which can be readily detected using bobbin probe inspection data. During the current outage inspection, no indications of tube slippage were identified during the evaluation of bobbin probe examination data from SGs "B" and "C." SG "A" will be evaluated as part of the inspection during the RF024 outage.