ML18331A162

Steam Generator Tube Inspection Report for the Spring 2018 Refueling Outage

ML18331A162
Person / Time
Site:	Surry
Issue date:	11/19/2018
From:	Mladen F Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
18-413
Download: ML18331A162 (11)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 NOV 1 9 2018 United States Nuclear Regulatory Commission Serial No.18-413 Attention: Document Control Desk SPS-LIC/CGL RO Washington, DC 20555-0001 Docket No. 50-280 License No. DPR-32 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 STEAM GENERATO R TUBE INSPECTION REPORT FORTHE SPRING 2018 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 T avg 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 2018 refueling outage.

If you have any questions concerning this information, please contact Mrs. Candee G. Lovett at (757) 365-2178.

Very truly yours, Fred Mladen Site Vice President Surry Power Station

Attachment:

Surry Unit 1 Steam Generator Tube Inspection Report for the Spring 2018 Refueling Outage Commitments made in this letter: None

Serial No.18-413 Docket No. 50-280 Page 2 of 2 cc: U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Avenu~ NE Suite 1200 Atlanta, Georgia 30303-1257 Ms. A. Schiller NRC Project Manager - Surry U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 07 E-5 11555 Rockville Pike Rockville, Maryland 20852-2738 Mr. J. R. Hall NRC Senior Project Manager - North Anna U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 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.18-413 Docket No. 50-280 ATTACHMENT SURRY UNIT 1 STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2018 REFUELING OUTAGE VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION ENERGY VIRGINIA)

Serial No.18-413 Attachment Docket No. 50-280 Page 1 of 8 SURRY UNIT 1 STEAM GENERATOR TUBE INSPECTION REPORT FOR THE SPRING 2018 REFUELING OUTAGE The following satisfies the Surry Power Station Technical Specification (TS) reporting requirement section 6.6.A.3. During the Surry Unit 1 Spring 2018 End-Of-Cycle 28 (EOC28) refueling outage, Steam Generator (SG) inspections in accordance with TS 6.4.Q were completed for SG A and SGC.

This was the fourth and final inspection in the 4th inspection period which has duration of 72 effective full power months (EFPM).

Surry Unit 1 exceeded 200°F on May 27, 2018; therefore, this report is required to be submitted by November 23, 2018. At the time of this inspection, the Unit 1 SGs had operated for 350.0 EFPM since the first in-service inspection.

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 included at the end of this report.

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, Primary Side During the Unit 1 EOC28 refueling outage, primary side inspections were performed in SG A and SG C. The eddy current inspections included the following:

SGs A and C:

• Full length bobbin inspection of all in-service tubing except the u-bends of Rows 1 and 2

• Motorized Rotating Pancake Coil (MRPC) inspections of the u-bends of Rows 1 and 2

• Array inspection of all in-service tubes from TSH -17.89" to the lowermost hot leg support structure (either BPH or 01 H)

• Array inspection of all in-service tubes from TSC -17.89" to the lowermost cold leg support structure (either BPC or 01 C)

• Full length Array inspection of all in-service tubes with high residual stress

• MRPC inspections of locations of special interest based on bobbin and array inspection results

Serial No.18-413 Attachment Docket No. 50-280 Page 2 of 8 As-found and as-left visual examinations were performed in both channel heads in SG A and SG C.

No degradation associated with the divider plate, welds, cladding, channel head, channel head drain or previously installed plugs was observed. Examination of the bottom of the bowl and drain in the dry condition showed no degradation.

Secondary Side Listed below is a summary of the secondary side work performed in the Surry Unit 1 steam generators during the EOC28 outage.

SGs A and C:

• Visual investigation of any accessible locations having eddy current signals potentially related to foreign objects.

SGC:

• Visual examination, from the steam drum of all accessible steam drum components and structures including the feedring, j-nozzles, and the primary and secondary moisture separators. The upper tube bundle and '7th tube support plate (TSP) were also inspected via probe drops through the primary moisture separators. No degradation or any other condition adverse to quality was observed during the secondary side internals inspections.

b. Degradation mechanisms found, Degradation mechanisms targeted by the inspection plan included anti-vibration bar (AVB) wear, pitting, foreign object wear, TSP wear and stress corrosion cracking (SCC). AVB wear, foreign object wear, and TSP wear were detected during the current outage. There was no reportable pitting and no cracking observed above the H-star region in 2018.

c. Nondestructive examination techniques utilized for each degradation mechanism, The inspection program focused on the degradation mechanisms listed in Table 1 and utilized the referenced eddy current techniques.

Serial No.18-413 Attachment Docket No. 50-280 Page 3 of 8 Table 1 - Inspection Method for Applicable Degradation Modes

.. Degradation' .. ~ ~ _"i,v "

.. > *~

. Clas~jfication **.Mechanism* Location* Probe Type

• --- *., *. ' *, *-*~ -

~ -::,.-.-- ---' . .... .. > -**--

Bobbin - Detection and Existing Wear Anti-Vibration Bars Sizing Bobbin and Array - Detection Existing OD Pitting Top-of-Tubesheet (T1S)

+Point' - Sizing Bobbin - Detection Existing Wear Tube Support Plate (TSP)

+Point' - Sizing Tube Wear Bobbin and Array - Detection Existing Freespan and TTS (foreign objects) +Point' - Sizing Tubesheet Overexpansions Array - Detection +Point' -

Existing PWSCC Sizing (OXP)

Existing PWSCC Tube Ends N/A*

Bobbin - Detection Existing Tube Wear Flow Distribution Baffle (FOB) +Point' - Sizing

/

Bulges, Dents, Manufacturing ODSCC Anomalies, and Above- Array - Detection +Point' -

Potential Sizing PWSCC Tubesheet Overexpansions (OVRs)

Tubesheet Crevice in Potential ODSCC Tubes With No Tube N/A**

Expansions (NTEs)

Potential Tube Slippage Within Tubesheet Bobbin - Detection ODSCC Array - Detection +PointTM -

Potential Hot Leg TTS PWSCC Sizing ODSCC +Point' - Detection and Potential Row 1 and 2 U-bends PWSCC Sizing Bobbin - Detection Potential ODSCC Freespan and Tube Supports

+Point' - Sizing ODSCC Bobbin and Array - Detection Existing High Residual Stress Tubes PWSCC +PointTM - Sizing

• Inspection not required per technical specification alternate repair criteria.

• • The tubes with no tubesheet expansion (NTE) have already been plugged.

Serial No.18-413 Attachment Docket No. 50-280 Page 4 of 8

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications, As stated in the (b) response above, service induced indications were identified. Tables 2 and 3 provide the required information.

Table 2 - Surry 1 Spring 2018 Inspection Summary- AVB Wear Indications I*,

. AVB,, '- .Depth (%~)c :

.. se3' Row Col'* Numper "

.. . . ,, . ' . *2018 A 9 54 AV1 13 A 12 45 AV1 13 A 12 45 AV4 12 A 12 47 AV4 15 A 21 86 AV2 11 A 30 57 AV2 12 A 30 57 AV3 12 A 32 14 AV4 9 A 32 48 AV3 11 A 32 65 AV2 11 A 32 66 AV2 9 A 32 69 AV2 21 A 32 69 AV3 16 A 32 69 AV4 17 A 33 16 AV2 12 A 33 63 AV3 20 A 33 63 AV4 16 A 33 66 AV1 11 A 33 66 AV2 13 A 34 59 AV2 12 A 35 17 AV2 12 A 35 78 AV2 14 A 36 47 AV1 11 A 36 75 AV2 15 A 36 76 AV2 11 A 37 75 AV2 12 A 37 75 AV3 12 A 38 62 AV4 8 A 38 73 AV3 11 A 39 42 AV1 15 ']

A 39 71 AV2 11

Serial No.18-413 Attachment Docket No. 50-280 Page 5 of 8

\

.AVB Depth (%TV~l)

SG Row Col a c" N'l..fmber 2018 ..

A 39 71 AV4 10 A 39 72 AV2 11 A 39 72 AV4 15 A 40 42 AV1 1'1 A 40 69 AV4 10 A 44 55 AV2 11 A 45 40 AV4 11 A 46 43 AV1 11 A 46 43 AV2 8 A 46 44 AV1 13 A 46 44 AV4 11 A 46 45 AV1 15 A 46 45 AV4 10 C 22 7 AV3 11 C 24 33 AV2 8 C 27 10 AV3 13 C 33 16 AV2 10 C 34 16 AV2 11 C 35 17 AV1 25 C 35 17 AV4 11 C 35 46 AV2 14 C 35 46 AV3 15 C 35 77 AV3 8 C 37 24 AV2 12 C 38 67 AV3 23 C 39 23 AV1 19 C 39 23 AV2 21 C 39 23 AV3 29 C 39 69 AV3 13 C 40 66 AV2 8 C 42 31 AV1 24 C 42 31 AV2 24 C 42 31 AV3 21 C 42 31 AV4 15 C 43 31 AV2 14 C 44 59 AV2 8 C 45 38 AV3 8 C 45 40 AV4 11 C 45 58 AV1 7 C 45 58 AV4 9

Serial No.18-413 Attachment Docket No. 50-280 Page 6 of 8 Table 3 - Surry 1 Spring 2018 - Summary of Non-AVB-Wear Volumetric Degradation Identified

.. Max Foreign

• - .PltJgg~~ &

SG Row Col* Location 00 Depth Cause Object-* **stabilized?-

.{%TW) Rerriainin*g?

Lancing TSC A 1 86 31 Equipment N/A No

+15.62" Damaqe 06C -

A 2 57 11 TSP Wear N/A No 0.59" 05C- Foreign A 3 66 26 No No 1.00" Obiect TSH Foreign A 6 88 25 No No

+0.10" Object TSH Legacy A 8 38 15 NIA No

+0.18" Pittinq TSH Foreign A 34 67 24 No No

+0.16" Obiect TSC 20 Removed

+0.03 Foreign A 38 27 During No TSC Object 23 EOC28

+0.66 TSC Foreign A 38 30 21 No No

+1.88" Obiect TSC Foreign C 3 52 34 No No

+0.34" Obiect 06C -

C 4 68 13 TSP Wear N/A No 0.54" BPH + Foreign C 26 85 29 No No 0.40" Object BPH Foreign C 27 82 27 No No

+0.39" Object BPH + Foreign C 29 82 28 No No 0.36" Object BPH -

C 36 24 6 FOB Wear N/A No 0.44" TSC- Foreign C 36 64 29 No No 0.02" Object TSC- Foreign C 36 66 24 No No 0.12" Object TSC- Foreign C 38 66 29 No No 0.09" Object BPH -

C 44 50 4 FOB Wear N/A No 0.45" BPH -

C 45 52 4 FOB Wear N/A No 0.44"

e. Number of tubes plugged during the inspection outage for each degradation mechanism, No tubes were plugged during the Unit 1 Spring 2018 refueling outage.

Serial No.18-413 Attachment Docket No. 50-280 Page 7 of 8

f. The number and percentage of tubes plugged to date, and the effective plugging percentage in each steam generator.

Table 4 provides the plugging totals and percentages to date.

Table 4 - Tube Plugging Summary Tubes* plugged Jo-Tubes*instaHed,

...

• 1,.

- '" ~ '

• h'* Date* *.,,

SGA 3,342 44 (1.3%)

SG B 3,342 26 (0.7%)

SGC 3,342 41(1.2%)

Total 10,026 111 (1.1%)

g. The results of condition monitoring, including the results of tube pulls and in-situ testing, All tubes with degradation identified during the Spring 2018 inspection satisfied condition monitoring requirements for SG tube structural and leakage integrity. Further, the results from the current outage inspection validate prior outage operational assessment assumptions. Tube pulls and in-situ pressure testing were not required during the current outage.

h. 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, Routine primary-to-secondary leak monitoring is conducted in accordance with station procedures. During the cycle preceding EOC28, no measurable primary-to-secondary leakage was observed in any Unit 1 SG.

i. 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 alternate repair criteria (PARC) requires that the component of operational leakage from the prior cycle from below the H-star distance be multiplied by

Serial No.18-413 Attachment Docket No. 50-280 Page 8 of 8 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 GPO originated from below the H-star distance, and multiplying this leakage by a factor of 1.8 as required by the PARC, yields an accident induced leakage value of <1.8 GPO. This value is well below the 470 GPO 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.

j. 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 and C. All tubes in SG B were screened for slippage during EOC27 (no indications were identified) and will again be screened during EOC29.

Acronyms AVB Anti-Vibration Bar BPC Baffle Plate Cold BPH Baffle Plate Hot C/L Cold Lea ECT Eddv Current Testina EFPM Effective Full Power Month EOC' End of Cvcle ETSS Examination Technique Specification Sheet FDB Flow Distribution Baffle GPD Gallons Per Dav H/L Hot Lea MRPC Motorized Rotatina Pancake Coil NSAL Nuclear Safety Advisorv Letter NTE No Tube Expansion OD Outer Diameter ODSCC Outside Diameter Stress Corrosion Crackina OVR Over Roll OXP Over Expansion PARC Permanent Alternate Repair Criteria PLP Possible Loose Part PWSCC Primary Water Stress Corrosion Crackina sec Stress Corrosion Crackina SG Steam Generator TEC Tube End Cold-lea TEH Tube End Hot-lea TSC Top of Tube Sheet Cold-leg TSH Top of Tube Sheet Hot-lea TSP Tube Support Plate TTS Top of Tubesheet TW Through Wall