ML15147A017

V.C. Summer, Unit 1 - Special Report (Apr) 2014-006, Response to Request for Additional Information

ML15147A017
Person / Time
Site:	Summer
Issue date:	05/21/2015
From:	Gatlin T D South Carolina Electric & Gas Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CR-15-01442, RC-15-0081
Download: ML15147A017 (6)

Text

if'Thomas D. GatlinVice President, Nuclear Operations 803.345.4342 A SCANA COMPANYMay 21, 2015Document Control DeskU. S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

VIRGIL C. SUMMER NUCLEAR STATION (VCSNS),

UNIT 1DOCKET NO. 50-395OPERATING LICENSE NO. NPF-12SPECIAL REPORT (SPR) 2014-006RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION

1. Letter from T. D. Gatlin (VCSNS) to Document Control Desk (NRC),"SPECIAL REPORT (SPR 2014-006),"

dated November 5, 2014[ML14314A033]

Reference:

2. Letter from S. A. Williams (NRC) to T. D. Gatlin (VCSNS),

"Virgil C.Summer Nuclear Station, Unit No. 1 -Request for Additional Information (TAC No. MF5164)",

date March 26, 2015[ML15079A099]

South Carolina Electric

& Gas Company (SCE&G),

acting for itself and as agent forSouth Carolina Public Service Authority pursuant to the requirements of Technical Specifications 6.9.1.12, submitted the Steam Generator Tube Inspection Report(Reference

1) following the 2014 Spring Refueling (RF-21) Outage. NRC's review ofReference 1 determined that additional information is required and a Request forAdditional Information (RAI) was issued per Reference

2. The Attachment of this lettercontains SCE&G's response to the RAIs in Reference 2.Should you have any questions, please call Mr. Bruce Thompson at (803) 931-5042.

Very truly yours,Thomas D. GatlinWLT/TDG/wm Attachment c: K. B. MarshS. A. ByrneJ. B. ArchieN. S. CamsJ. H. HamiltonJ. W. WilliamsW. M. CherryV. M. McCreeS. A. WilliamsNRC Resident Inspector K. M. SuttonINPO Records CenterNSRCRTS (CR-15-01442)

File (818.08)PRSF (RC-15-0081)

AL)D(V. C. Summer Nuclear Station

• P. O. Box 88

• Jenkinsville, SC .29065 -F (803) 941-9776 Document Control DeskAttachment CR-15-01442 RC-1 5-0081Page 1 of 5VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1DOCKET NO. 50-395OPERATING LICENSE NO. NPF-12ATTACHMENT IRequest for Additional Information (RAI) Response Document Control DeskAttachment CR-1 5-01442RC-15-0081 Page 2 of 5VC Summer Spring 2014 Steam Generator Inspection Report RAIsBy letter dated March 26, 2015 [ML15079A099],

NRC requested the following information to continue review of the Spring 2014 steam generator tube inspections performed at Virgil C. Summer Nuclear Station, Unit 1.RAI No. 1:Please provide the cumulative number of effective full power months (EFPMs)that the steam generators had operated for the last 4 refueling outages.

Pleasealso provide the number of EFPMs that the steam generators (SGs) had operatedat the time of the first inservice inspection.

VC Summer Response:

The approximate cumulative effective full power months (EFPM) that the VC SummerSteam Generators have operated are identified below.1st ISI -RF-09 (Spring 1996) -15.3 EFPMRF-17 (Spring 2008) -141.9 EFPMRF-18 (Fall 2009)- 157.6 EFPMRF-19 (Spring 2011)- 173.3 EFPMRF-20 (Fall 2012) -189.7 EFPMRF-21 (Spring 2014) -205.2 EFPMRAI No. 2:Please discuss the results of the channel head bowl inspections, upper bundlevideo inspection in SG A, steam drum inspections, and tube plug inspections.

Forthe tube plug inspections, were all plugs present and in their proper locations?

Was any degradation observed?

VC Summer Response:

Channel Head Bowl Inspections Westinghouse Nuclear Safety Advisory Letter NSAL-1 2-1 recommends visualinspection of the channel head near the bowl drain line to determine if degradation ofthe cladding and potential degradation of the channel head base material haveoccurred.

All three SG channel heads were visually inspected during RF-21. Theobserved conditions were consistent with the manufacturing process and did not exhibitany signs of degradation.

Visual inspection concluded that a condition similar to thatdocumented in NSAL-12-1 does not currently exist at VC Summer.

Document Control DeskAttachment CR-15-01442 RC-15-0081 Page 3 of 5Tube Plug Inspections Five tubes were plugged in the VC Summer Steam Generators during RF-12 (Fall2000). This was the last outage when tubes were plugged at VC Summer. Three tubeswere plugged prior to installation at the factory.

The cumulative total number of tubeplugs is eight.All installed plugs were inspected for degradation and evidence of leakage.

All plugswere determined to be in their proper location.

No degradation was noted. No drippingplugs were identified and all plugs were found to be dry.Upper Bundle Video Inspection in SG AA tube lane and in-bundle inspection was performed on the top tube support plate of SGA. The inspection was performed in the tube lane as well as in approximately everytenth column of the tube bundle on both the hot leg and cold leg sides.The inspection of the tube lane region of the top tube support plate resulted in no tubewear, anomalies, or foreign objects being observed.

Very little loose sludge was foundin the tube lane while no hard sludge was observed.

The support plate's circular flowholes in the tube lane region were clear of sludge and other deposits while the centerstayrod nuts observed were intact and appeared to be in good condition.

Finally, thevisible anti-vibration bars were all intact and properly aligned.During the in-bundle inspections, no tube wear, tube anomalies, or foreign objects wereobserved.

In addition, no support plate anomalies, such as ligament cracking or loss ofmaterial, were observed.

The tube column gaps were relatively clean but some loosesludge was observed in-bundle on the top surface of the support plate. The supportplate did possess some partial blockage of some of its quatrefoils due to the loosesludge.

Document Control DeskAttachment CR-1 5-01442RC-1 5-0081Page 4 of 5Steam Drum Inspections Visual inspections of the steam drum region were performed in all three steamgenerators.

The visual inspections included examinations of all visibly accessible components within the steam drum region of each steam generator.

The goal of thesteam drum visual inspections was to provide an overall inspection of each steamgenerator's steam drum components and to identify any evidence of degradation, damage, deformation, anomalies, abnormalities, loose parts, potential loose parts, andforeign objects.

The following components were inspected:

" Primary Moisture Separators

" Secondary Moisture Separators

" Steam Outlet Nozzle" Internal Deck Plates* Feedwater Ring and Nozzles* Auxiliary Feed Pipe and Nozzle* Sludge Collector Assembly* Shell Inner Diameter SurfaceThe inspections revealed no visible signs of degradation or structural issues that wouldprohibit continued steam generator operation and threaten tube integrity until the nextscheduled steam drum inspections.

4'.Document Control DeskAttachment CR-15-01442 RC-1 5-0081Page 5 of 5RAI No. 3:In Table 2, there is an inspection category for "cold leg new bobbin wear." Wereall of the new wear indications located on the cold leg? If not, were new wearindications in the hot leg inspected?

VC Summer Response:

The category identified in Table 2 of the RF-21 VC Summer Steam Generator TubeInspection Report as "cold leg new bobbin wear" was a special interest inspection that isa bobbin retest using an AVB wear standard.

The same special interest inspection wasperformed on the hot leg as well. Hot Leg Inspection Scope is in Table 1.Table 1 -Hot Leg Bobbin Retestwith AVB StandardSGA SGB SGC2 6 4RAI No. 4:Please discuss which tubes would not pass a bobbin probe. Were these all lowrow (i.e., rows 1 and 2) tubes? If not, please discuss the nature of the restrictions in these tubes.VC Summer Response:

Inspection scope discussed in Section 2 of RF-21 VC Summer Steam Generator TubeInspection Report Inspection report described:

1) U-bend +Point inspection of tubes that a bobbin probe would not pass throughThis statement referred to a planned inspection scope of low row u-tubes.

There wereno restricted/blocked tubes that a bobbin probe would not pass through.

As such, as-tested inspection scope did not change from the planned inspection scope. Sample sizefor this inspection scope is identified in Table 2.Table 2 -U-Bend +PointInspection of Low Row U-TubesSG A SG B SG C23 44 40