ML16343A541

Summary of 971002 Meeting W/Tva in Rockville,Md Re Planned Use of Electrosleeving Process at Sequoyah Nuclear Plant, Units 1 & 2 & Diablo Canyon Power Plant to Repair & Strengthen SG Tubing.List of Attendees & Handouts Encl

ML16343A541
Person / Time
Site:	Diablo Canyon, Sequoyah
Issue date:	11/12/1997
From:	Hernan R NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9711280226
Download: ML16343A541 (52)

Text

November 1

1997 LICENSEE: Tennessee Valley Authority FACILITY:

Sequoyah Nuclear Plant, Units 1 and 2

SUMMARY

- OCTOBER 2, 1997, MEETING WITH TVATO BRIEF THE STAFF ON THE THIN ELECTROSLEEVE REPAIR METHOD On October 2, 1997, representatives of the Tennessee Valley Authority (TVA),the licensee for the Sequoyah Nuclear Plant (SQN) met with members of the Nuclear Regulatory Commission (NRC) staff in Rockville, Maryland. TVArequested this meeting to discuss planned use of an electrosleeving process at SQN and the Diablo Canyon Power Plant (DCPP) to repair and strengthen steam generator tubing. Representatives of Framatome Technologies, Inc. (FTI),

Pacific Gas & Electric (PG&E), and Public Service Electric and Gas (PSE8G) also participated in the meeting. A list of attendees is given in Enclosure 1. The nonproprietary portion of the handout provided by TVAduring the meeting is included as Enclosure 2.

TVArepresentatives discussed a jointly-funded program being developed by TVA, FTI, PG8 E, and possibly PSE8G, for use of a preventive and repair method using a thin electrosleeve deposited on the inside of steam generator tubes.

The Electric Power Research Institute (EPRI) willalso participate in nondestructive examination associated with this method.

SQN Unit 1 and both DCPP units have experienced primary water stress corrosion cracking in the tube support plate (TSP) regions of their steam generators, in most cases as the result of tube denting. Sleeves about 4 inches long and about 10 mils thick will be deposited on the internal diameter in the TSP regions.

Qualification of this sleeving method is expected to be complete in January 1998 and submittal to the NRC is scheduled for February 1998. The first planned application will be at SQN Unit 1 in the Fall of 1998.

/S/

Ronald W. Hernan, Senior Project Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosures:

1. Attendance List

2. TVAHandout cc w/enclosures:

See next page DOCUMENT NAME: G:ttSQNiiMTGSUM10.2 To receive a copy of this document. indicate In the botu "C

~ Copy without attachment/enclosure E" ~ Copy with attachment/enclosure "N"

No copy IIIIIIIIIIIIIIII,IIIIIIII IIIIIIIIIIII i OFFICE PDII-3/PM NAME RHernan DATE 11/

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 12, 1997 LICENSEE: Tennessee Valley Authority FACILITY:

Sequoyah Nuclear Plant, Units 1 and 2

SUMMARY

- OCTOBER 2, 1997, MEETING WITHTVATO BRIEF THE STAFF ON THE THIN ELECTROSLEEVE REPAIR METHOD On October 2, 1997, representatives of the Tennessee Valley Authority (TVA),the licensee for the Sequoyah Nuclear Plant (SQN) met with members of the Nuclear Regulatory Commission (NRC) staff in Rockville, Maryland. TVArequested this meeting to discuss planned use of an electrosleeving process at SQN and the Diablo Canyon Power Plant (DCPP) to repair and strengthen steam generator tubing. Representatives of Framatome Technologies, lnc. (FTI),

Pacific Gas 8 Electric (PG8E), and Public Service Electric and Gas (PSE8G) also participated in the meeting. A list of attendees is given in Enclosure 1. The nonproprietary portion of the handout provided by TVAduring the meeting is included as Enclosure 2.

TVArepresentatives discussed a jointly-funded program being developed by TVA, FTI, PG8E, and possibly PSE&G, for use of a preventive and repair method using a thin electrosleeve deposited on the inside of steam generator tubes.

The Electric Power Research Institute (EPRI) willalso participate in nondestructive examination associated with this method.

SQN Unit 1 and both DCPP units have experienced primary water stress corrosion cracking in the tube support plate (TSP) regions of their steam generators, in most cases as the result of tube denting.

Sleeves about 4 inches long and about 10 mils thick willbe deposited on the internal diameter in the TSP regions.

Qualification of this sleeving method is expected to be complete in January 1998 and submittal to the NRC is scheduled for February 1998. The first planned application willbe at SQN Unit 1 in the Fall of 1998.

Docket Nos. 50-327 and 50-328 Ronald W. Herna, Senior Project Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Enclosures:

1. Attendance List

2. TVAHandout cc w/enclosures:

See next page

'E

CC:

Hr. 0. J. Zeringue Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A, Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Hr. Jack A. Bailey Vice President Engineering

& Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Hr. Hasoud Bajestani Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O.

Box 2000 Soddy Daisy, TN 37379 General Counsel Tennessee Valley Authority ET IOH 400 West Summit Hill Drive Knoxville, TN 37902 Hr. Raul R. Baron, General Manager Nuclear Assurance Tennessee Valley Authority 4J Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Mark J, Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4J Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 SEQUOYAH NUCLEAR PLANT Hr. Pedro Salas, Manager Licensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O.

Box 2000 Soddy Daisy, TN 37379 Hr.-J. T. Herron, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O.

Box 2000 Soddy Daisy, TN 37379 Regional Administrator U.S. Nuclear Regulatory Commission

~ Region II 61 Forsyth Street, SW.

Suite 23T85

Atlanta, GA 30303-3415 Mr. Melvin C.

Shannon Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Michael H. Hobley Director Division of Radiological Health 3rd Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Executive Hamilton County Courthouse Chattanooga, TN 37402-2801

t

D COPY w/Enclosures 1 and 2 Docket File PUBLIC SQN Reading R. Hernan HARD COPY w/E closure1 OGC ACRS E-Mail w/Enclosure 1

S. Collins/F. Miraglia (FJM)

R. Zimmerman (RPZ)

B. Boger (BAB2)

J. Zwolinski (JAZ)

P. Rush C. Beardslee E. Sullivan J. Tsao E. Bebek-Mathet T. Martin (SLM3)

M. Gamberoni (MKG)

J. Johnson (JRJ)

G. Holahan (GMH)

~ g

0 E

DEES NRC A MEE ING 0 OCTOBER 2 99 EG D

G LEC OSLEEV G

Ronald Heman Phillip Rush Cheryl Beardslee Edmund Sullivan John Tsao Jim Davis Eric Bebek-Mathet NRC NRC NRC NRC NRC NRC NRC Pedro Salas David Goetcheus John Brooks Christine Campbell Randy Schaefer John Helmey John Arhar Bob Exner David Hughes TVA FTI FTI PG&E PG8E PSE8G ENCLOSURE I

0

~f S

THINELECTROSLEEVE REPAIR METHOD NRC PRESENTATION OCTOBER 2,1997 INTRODUCTION DAVIDGOETCHEUS ENCLOSURE 2

THINKLKCTROSLKKVKREPAIR METHOD

~

Sequoyah Unit 1 and Diablo Canyon Units 1 and 2 steam generators'ost significant problem is PWSCC at dented tube support plate intersections 228 tubes plugged to date SQN Unit 1 237 tubes plugged to date DCPP Unit 1 93 tubes plugged to date DCPP Unit 2 Significant increases identified in most recent inspections at all 3 units Is projected to ultimately affect the life ofthe generators nuc maint'egeuchclcctroslccvc.ppt

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~ 4

THINKLKCTROSLKKVKREPAIR METHOD Total SQN U1 dents - 9,7S4 Total SQN U2 dents - 1,020 Total DCPP U1 dents-15,521 Total DCPP U2 dents-5,509 Dented tube support plate intersection with circumferential ID and OD cracking (OD cracking at SQN Ul only)

SQN Unit 1, DCPP UnitI, and 2 tube condition QN Unit 2 tube condition Primary water axial ID cracking Rom dent stress field

[,t Tube support plate corrosion non-protective magnetite Non-dented tube support plate intersection with axial OD cracking nuc maintbglnreleleetrosleeve.ppt

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THINKLKCTROSLKKVKREPAIR METHOD Stm Plant

- Unit Gen No./Size Dents PWSCC ODSCC PWSCC?

Locations ODSCC?

Locations Sequoyah 1

1 >=5V 194

<5 V 421

-2 >=-5 V 52

<5 V 326 3 >=5V 1079

<5 V 2836 9 Axial H01 8 H02 4 Axial H01 8 H02 86 Axial '01-H04 12 Circ 3 Axial 8 Circ 1 Circ 5 Axial 16 Circ Primarily H01 Primarily H01 Primarily H01 nuc maint'bg~telcctrosleevc.ppt 4 >=5V 2685

<5 V 2191 1 >=5V 106

<5 V 347 2 >=5V 8

<5V

'22 3 >=5V 47

<5 V 192 4 >=5V 10

<5 V 188 95 Axial 22 Circ No H01-H04 1 Axial 27 Circ No Primarily H01

r 1

I

THINELECTROSLEEVE REPAIR METHOD Stm Plant Unit Gen No./Size Dents PWSCC ODSCC PWSCC?

Locations ODSCC?

Locations Diablo Canyon nuc maintbgtmchelectrosleeve.ppt 1 >=5V 203

<5 V 2221 2 >=5V 358

<5 V 3259 3 >=GV 204

<5 V 2527 4 >= 5 V 1233

<5 V 5516 1 >=5V 8

<5 V 1108 2 >=5V 517

<5 V

'l677 3 >=GV 8

<5 V 775 4 >=5V 43

<5 V 1373 39 Axial 179 Axial 1 Circ 20 Axial 77 Axial 16 Circ 3 Axial 15 Axial 1H,2H,3H 1H,2H,3H, 4H 5H 6H 1H,2H,3H 1H,2H, 4H GH 1H,3H 1H,2H,3H 8 Axial 7 Axial 2 Axial 2 Axial 1 Axial 4 Axial No 14 Axial Primarily

'lH Primarily 1H Primarily 1H Primarily 1H Primarily 1H 2H Primarily 1H 2H Primarily 1H 2H

THINKLKCTROSLKEVKREPAIR METHOD Vl O

ceO

'Uc SQN U1C8 SG 1 PWSCC AT DENTED TSPs 30 20 10 IhcO ce CP c

30 20 10 SQN U1C8 SG 2 PWSCC AT DENTED TSPs 0

H01 H02 H03 H04 SUPPORT PLATE 0

H01 H02 H03 SUPPORT PLATE H04 El <2V DENT% >cc2V & <5V DENT 0

>cc5V DENT El <2V DENT% >-"2V&<<5V DENT 0

>ccSV DENT 30 N

o 20 O

~c 10 0

SQN U1C8 SG 3 PWSCC AT DENTED TSPs

> ~";.->Ms.e;;",aM~~~."'".:

.>n%:~c4":""W:iZ

30 cec 20 ce Cl 10 0

SQN U1C8 SG 4 PWSCC AT DENTED TSPs H01 H02 H03 H04 SUPPORT PLATE H01 H02 H03 SUPPORT PLATE H04 8 <2VDENTI >cc2V&<5VDENT0 >~SVDENT 8 <2V DENTS >cc2V &<5V DENT 0

>ccSV DENT nue maintbgtntehelectrosleevc.ppt

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5

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THINKLKCTROSLKKVKREPAIR METHOD 1000 800 i,Q 600

~ Lll 400

~ LL 200 z

0 U1 Sequoyah Unit 1 C6 U1 CT U1 C8 U1 C9 U1 C10 OUTAGE RASCC Axial -arPIASCC Qrc mc mainfbg~hel~leeve.ppt

~

THINKLKCTROSLKKVKREPAIR METHOD 7000

'000 W-S/G MOD 5't PWSCC TSP DENTED ACTUAL/PROJECTED REPAIR RATES 7 Unifs 14.6Avg. Comm. Fears L 5000 z

0'4000 g 3000 I-2000 1000 nuc maint'bg~helcctrosleeve.ppt 10 15 20 25 30 YEARS COMMERCIALCONTINUOUS

~ LOWER AVG. ~ MEDlAN

~ UPPER AVG.

~ SQN U1 (ACTUAL~SQN U2 (ACTUAL) 35 40

P

THINKLKCTROSLKKVKREPAIR METHOD Apreventive and repair method using a thin electrosleeve is being developed in a jointly funded program with FTI, PGkE, TVA,and possibly PSE&G. EPRI willparticipate in the NDE portion.

Thin electroplating on the ID surface ofthe tube

~ Capabilities have already been demonstrated in European 'steam generators for hard roll expansion transition PWSCC Applyto TSP dented intersections to prevent PWSCC Apply as a.repair to detected PWSCC at dented intersections Applyto higher voltage GL 95-05 APC indications to reduce total leakage Serves as structural repair for ODSCC (axial and circumferential) up to a predetermined extent nue maiattsg~eleetrosleeve.ppt

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THINKLKCTROSLKKVKREPAIR METHOD

~

Advantage ofthe thin electrosleeve over other sleeve techniques Does not impart residual stress to parent tube during installation Minimizes flow loss an.d therefore can be utilized in a large number of dented intersections and multiple intersections in one tube

• Can be, reapplied to the same tube, i.e. can sleeve above an existing sleeve, can be installed over existing electrosleeve Faster to apply and therefore facilitates preventive sleeving. More tubes can be sleeved in an outage ~

~ Advantages unique to thin sleeve nuc maiatbgtmctelcctmslcevc.ppt 10

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THINKLKCTROSLKKVEREPAIR METHOD

~

Program Objectives Demonstrate through. qualification testing that the thin electrosleeve improves tube structural integrity in the presence of circumferential and axial flaws Demonstrate through qualification testing that the thin electrosleeve prevents accident leakage when applied to existing cracks Qualify an EPRI Appendix H NDE method for inservice inspection

~

Preliminary Test Results Substantial improvement in burst pressure nuc maintlsgtnrehelcctrosleeve.ppt

~I

QUALIFICATION PROGRAM

~ DEFINE REQUIREMENTS

~

PWSCC EVALUATION Prevents Initiation Stops Growth

~

STRUCT QUALIFICATION Define Maximum Defect Leakage Burst NDE QUALIFICATION Define Requirements Detection Extent Sizing UT / ECT

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REPAIR REQUIREMENTS

~ PWSCC PREVENTION/REPAIR Ir Prevent Initiation Stop Growth

~

ODSCC REPAIR Defect Extent Specific Prevent Leakage Provide Burst Margin Tubes Remain in Service Based on Extent, Not Depth

~ Assume 100% Through-wall

~

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t THINSLKKVE DESCRIPTION AV2 Series-51 S/

V3AV4

- Electrosleeve Material

- 0.010" Wall Thin-Sleeve

- 4" Long

- Apply at Dented / Non-Dented Intersections

- Exclude Top TSP

- Exclude Tubes at High LoadWedge Regions

@ca" >~>~s%W gYw~

micr TSP 07H 06H 05H 04H

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p LLwi@wgwa RC:

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!4 44 07C 06C 05C 04C 03C 02C OIC Low Flow Loss old p

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- Protects Tube ID

- Prevents Leakage 8c Burst

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PWSCC EVALUATION

~ EXISTINGDATABASE Electrosleeve Corrosion Tests Pressurizer Repair Plant Experience WithNickel

~

CORROSION TESTS Dented Tube Samples

~ Pre-Cracked

~ Thin Sleeve Over Defects Steam Test To Evaluate:

~ PWSCC Initiation

~ PWSCC Growth Destructively Examine

~'i P

4 ll

~~

STRUCTURAL QUALIFICATION ANALYSES Target Defect Length / Sleeve Wall

~ Determine By Test Fatigue FIV Primary Flow

~ 800:1 Repair:Plug Equivalency TEST SAMPLES Range ofDent Sizes Representative ofPlant Dents

< 2 volts - 40 volts Range ofDefects

~ Axial0 Circ

~ Various Lengths

~

100% Tkml-wall Tube Tube Ec Sleeve

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STRUCTURAL QUALIFICATION

~ LEAKTESTS MSLB Pressure Adjusted For Temperature

~ BURST TESTS Freespan (No TSP)

~ DEFINE PLUGGING CRITERIA

Wp

STRUCTURAL QUALIFICATIOX TEST. SAMPLE EDMNOTCH (AXIAL)

THINELECTROSLEEVE 0.875 "OD X 0.050" %ALL I600 TUBE

~ I) i P

NDE QUALIFICATION

~ CONFIRM INSPECTION CAN BE PERFORMED TO CRITERIA

~ QUALIFYECT k, UT Parallel Activity EPRI Participating

~ Industry Round-Robin

~ PULLED TUBES Salem Unit l Re-Analyze Data for Extent

~

CORROSION SAMPLES 30 Mechanically Dented Tubes Steam Test to Produce Representative ODSCC

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SUMMARY

Keep SGs Alive

~ No Replacement Manage PWSCC Degradation with:

~ PWSCC ARC (WCAP 14707)

~ Thin-Sleeve Repair

~ Electro sleeve

~ Standard Sleeving

~ Zinc Addition THIN-SLEEVEREPAIR Valuable Tool for Defect Management

~ Large No. ofDents

~ PWSCC Provides a Preventative Option Provides Margin

~ Burst, Leakage Maximizes Core Flow Margin Maximizes Steam Pressure

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SUMMARY

~

SCHEDULE Qualification Submittal Application

~ Sequoyah 1

Jan '98 Feb '98 Fall '98

~ Diablo Canyon 1

Spring '99

~ NRC REVIEW Concept Based on Electrosleeve

~ Same Material S Process

~ Depth Measurement Eliminated Feedback on Concept Requested

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