ML12187A165
| ML12187A165 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 06/22/2012 |
| From: | Lane N Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-392, FOIA/PA-2013-0030, FOIA/PA-2013-0139 | |
| Download: ML12187A165 (7) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 June 22, 2012 United States Nuclear Regulatory Commission Serial No.12-392 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 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION 2011 STEAM GENERATOR INSERVICE INSPECTION REPORT By letter dated October 5, 2011 (Serial No.11-495), Virginia Electric and Power Company (Dominion) submitted information summarizing the results of steam generator (SG) tube inspections performed at Surry Power Station Unit 2 during the Spring 2011 refueling outage. On May 23, 2012, the NRC requested additional information related to the SG inspections. The NRC's questions and Dominion's responses are provided in the attachment to this letter.
If you have any questions or require additional information, please contact Ms. Candee Lovett at (757) 365-2178.
Very truly yours, N. L. Lane Site Vice President Surry Power Station Attachments:
- 1. Response to NRC Request for Additional Information Regarding 2011 Steam Generator Inservice Inspection Report - Surry Power Station Unit 2
- 2. List of Acronyms from Letter Serial No.11-495 (Attachment page 13 of 13) - Surry Power Station Unit 2 Commitments made in this letter: None A AA1V
Serial No.: 12-392 Docket No.: 50-281 Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303 NRC Senior Resident Inspector Surry Power Station Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 0 8G-9A 11555 Rockville Pike Rockville, Maryland 20852 Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 0 8G-9A 11555 Rockville Pike Rockville, Maryland 20852 Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station
Serial No.: 12-392 Docket No.: 50-281 ATTACHMENT 1 Response to NRC Request for Additional Information Regarding 2011 Steam Generator Inservice Inspection-Report Surrv Power Station Unit 2 Virginia Electric and Power Company (Dominion)
Serial No.: 12-392 Docket No.: 50-281 By letter dated October 5, 2011 (Serial No.11-495), Virginia Electric and Power Company (Dominion) submitted steam generator (SG) tube inspection results from the 2011 inspections at Surry Unit 2. On May 23, 2012, the NRC requested additional information related to the SG inspections. The NRC questions and Dominion's response are provided below.
NRC Question 1 The staff understands that a hole was discovered in a riser barrel in the steam generator upper internals. As a result, further inspections of this area were performed and several riser barrels were repaired with Y" inconel plates. Please discuss the nature and cause of the holes. Please discuss the scope and results of any other secondary side inspections other than those discussed on page 3 of the attachment to your October 5, 2011 letter.
Dominion Response During the feedring replacement work in SG "A," a hole in one of the primary separator riser barrels was identified coincident with a J-Nozzle overspray location.
The riser barrel arrangement is configured into two concentric circles. The outer circle consists of twelve evenly spaced riser barrels located on the outside of the feedring (between the feedring and steam drum ID). The remaining four riser barrels, forming the inner circle, are located on the inside of the feedring.
Ultrasonic (UT) wall-thickness measurements were performed on six of the sixteen SG "A" riser barrels which visually showed J-Nozzle overspray.
The regions, which had reduced wall thickness, were addressed by welding an Inconel patch plate over the affected areas. Inconel patch plates were previously installed on the susceptible riser barrels in SGs "B" and "C," and the J-nozzles on the replacement feedrings in all three SGs are orientated such that the spray does not impinge on the riser barrels.
The discussion on page 3 of the attachment to the October 5, 2011 letter reflects the secondary side inspections completed. No other secondary side inspections were performed.
NRC Question 2 Please clarify the nature/cause of the previous indications in the tubesheet in Table 2.
Dominion Response The previous indications referred to in Table 2 include previously identified tube degradation, as well as locations of interest monitored due to previous foreign object indications. The tubes identified had indications caused by previous loose parts at or near the Top of Tubesheet. None of the tubes indicated had loose parts in the area of these indications.
Page 1 of 2
Serial No.: 12-392 Docket No.: 50-281 NRC Question 3 Please clarify the nature/extent of the tube with the restriction in Table 2.
Dominion Response The tube with the restriction (SGC R1 C58) has a relatively large historical dent at the top of the tubesheet on the cold leg. The dent prevents passage of the 0.720 inch diameter bobbin probe but permits passage of the 0.700 inch diameter bobbin probe. To ensure effective examination of the tube, the entire cold leg and u-bend of this tube were examined with a +Point probe (the hot leg was examined with a 0.720 inch diameter bobbin probe). No degradation was identified.
NRC Question 4 There is a column titled "Foreign Object Remaining?" in Table 5. Was the determination of no object remaining based on visual inspections of the areas? If not, discuss the basis for determining whether a foreign object was present.
Dominion Response The determination in Table 5 of no object remaining is based either on visual examination results, eddy current examination results, demonstrated absence of degradation advancement, or a combination of this information. For most, the basis of the determination is the absence of an eddy current +point probe foreign object indications at or near the flaw location. This determination is further supported by the demonstrated absence of flaw growth through multiple cycles of operation.
NRC Question 5 There are several locations where the indication was "initially reported" in 2011, yet there were signals present in prior outages in Table 5. For all the tubes for which this is the case, was the prior presence of the signal based on re-analysis of prior cycle data? Please clarify this item.
Dominion Response Yes, for the cases where the indication is noted as initially reported in 2011 and for which a prior signal was present, the determination was based on a re-analysis of prior outage data.
NRC Question 6 The pages of the attachment to your October 5, 2011 letter are numbered 'Y" of 13. The NRC received 12 pages. Please provide the missing page.
Dominion Response Page 13 of 13 in the Attachment to the October 5, 2011 letter was the list of acronyms used. A copy of that page is included in Attachment 2 to this letter.
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Serial No.: 12-392 Docket No.: 50-281 ATTACHMENT 2 List of Acronyms from Letter Serial No.11-495 (Attachment page 13 of 13)
Surrv Power Station Unit 2 Virginia Electric and Power Company (Dominion)
Serial No.: 11-495 Attachment Docket No.: 50-281 Page 13 of 13 Acronyms ARC Alternate Repair Criteria AVB Anti Vibration Bar BCX Cold Leg BET BET Bottom of the expansion transition BHX Hot Leg BET BLG Bulge BPH Baffle Plate Hot c
Column CM Condition Monitoring CMOA Condition Monitoring Operational Assessment C/L Cold Leg DEP Deposit DMT Deposit Management Treatment DNG Ding DNT Dent ECT Eddy Current Testing EFPY Effective Full Power Years EOC End of Cycle ETSS Eddy Current Technical Specification Sheets FAC Flow Assisted Corrosion FB Fan Bar FDP Flow Distribution Baffle FO Foreign Object FOSAR Foreign Object Search and Retrieval GPD Gallons Per Day LGV Localized Geometric Variation H/L Hot Leg LPI Loose Part Indication MBH Historical Manufacturing Brandish Mark MBM Manufacturing Burnish Mark MRPC Motorized Rotating Pancake Coil NOP Normal Operating Pressure NTE No tube Expansion NQH Non-Quantifiable Historical Indication NQI Non-Quantifiable Indication OA Operation Assessment OD Outer Diameter ODSCC Outside Diameter Stress Corrosion Cracking OVR Over Roll OXP Over Expansion PLP Possible Loose Part PTE Partial Tubesheet Expansion PVN Permeability Variation PWSCC Primary Water Stress Corrosion Cracking
% TW Percent Throughwall R
Row RPC Rotating Pancake Coil SG Steam Generator SLG Sludge SAI Single Axial Indication SCI Single Circumferential Indication SSI Secondary Side Inspection SVI Single Volumetric Indication Tavg Average Reactor Coolant System Temperature TEC Tube End Cold-leg TEH Tube End Hot-leg TSC Top of Tube Sheet Cold-leg TSH Top of Tube Sheet Hot-leg TSP Tube Support Plate TTS Top of Tubesheet TW Through Wall UT Ultrasonic Testing VOL Volumetric Indication WAR Wear Indication