ML20209F692

Summary of 870417 Meeting W/Util,Southern Co Svcs,Nus Corp & Westinghouse Re Leak Before Break Methodology Applied to Auxiliary Lines & Steam Generator Snubber Reductions.Util Presentation & List of Participants Encl

ML20209F692
Person / Time
Site:	Vogtle
Issue date:	04/22/1987
From:	Mark Miller Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8704300348
Download: ML20209F692 (31)

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APPLICANT: Georgia Power Company FACILIT/: Vogtle, Unit 2

SUMMARY

OF MEETING HELD ON APRIL 17, 1987 TO DISCUSS LEAK-BEFORE-BREAK METHODOLOGY APPLIED TO AUXILIARY LINES AND STEAM GENERATOR SNUBBER REDUCTIONS On April 17, 1987, the staff met with the applicant and its representatives to discuss the application of leak-before-break technology to auxiliary lines and steam generator (SG) snubber reduction for Unit 2. Participants are listed in Enclosure 1. The applicant's presentation slides are included in Enclosure 2.

The applicant explained that the SG snubber reductions will be described in a future FSAR amendment and that an exemption is not necessary under the current GDC 4. On Unit 2 approximately 70% of both small and large bore piping are installed. The applicant has put a hold on installation of pipe whip restraints.

The applicant emphasized the primary benefits obtained through snubber reduction and elimination of pipe rupture restraints. In the leak-before-break analysis the applicant will still analyze for pipe breaks at the loop connection with the accumulator, residual heat removal, and surge lines as well as the main steam and feedwater line breaks at the SGs. This results in additional margin in the heavy component support structures. In reducing the number of snubbers per loop from 5 to 2, the applicant will show that the remaining snubbers can still perform their function under con:bined safe shutdown earthquake loads and the limiting high energy line break. The applicant will ensure that the leak-before-break analysis on the primary loop remains valid as a result of SG snubber reduction.

Preliminary indications are that primary coolant loop leak-before-break reanalysis will not be required.

Each of the 5 snubbers currently installed per SG are designed to 1000 kips.

Slide 8 shows the snubbers that will remain. Upon removal of 3 snubbers, the stiffness in the opposite direction will not change because the bumper is unaffected.

The applicant indicated that the Westinghouse computer analysis for the reactor coolant loop piping, WESTDYNE, has been independently reviewed and validated by Lawrence Livennore National Laboratory. The review has been documented in NUREG/CR-3660. The Westinghouse model for the snubber reduction will not change from that in the original Vogtle analysis other than reducing the number of snubbers considered.

8704300348 870422 DR ADOCK 05000424 PDR

. The Vogtle pressurizer surge line has a reducer which constitutes the major difference between it and the pressurizer surge line on South Texas.

The portions of each of the lines to be analyzed using leak-before-break are outlined in Slides 14-16. The methodology for these branch lines is not dif-ferent from the previous Westinghouse leak-before-break methodology presented to the staff.

The staff requested the applicant to discuss operator actions and administra-tive procedures regarding leak rate detection.

The staff indicated that it will provide clarifying information to the applicant on the leak-before-break issue regarding (1) what material properties should be considered in leak rate calculations and (2) treatment of branch lines not explicitly included in leak-before-break analyses.

h3 L h. a 'O Melanie A. Miller, Project Manager Project Directorate II-3 Division of Reactor Projects-I/I!

Enclosures:

As stated cc: See next paga l

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&kk The Vogtle pressurizer surge line has a reducer which constitutes the major difference between it and the pressurizer surge line on South Texas.

The portions of each of the lines to be analyzed using leak-before-break are outlined in Slides 14-16. The methodology for these branch lines is not dif-ferent from the previous Westinghouse leak-before-break methodology presented to the staff.

The staff requested the applicant to discuss operator actions and administra-tive procedures regarding leak rate detection.

The staff indicated th'.t it will provide clarifying information to the applicant ontheleak-before-breakissueregarding(1)whatmaterialpropertiesshouldbe considered in leak rate calculations and (2) treatment of branch lines not explicitly included in leak-before-break analyses, t.

Mela fe A. Miller, Project Manager Project Directorate II-3 Division of Reactor Projects-l/II

Enclosures:

As stated cc: See next page

• SEE PREVIOUS CONCURRENCES PD fQRP-I/II NRR/EMEB NRR/ENTB PD# I/II HM /mac *TSu111 van *KWichman BJYoung 04/ /87 04/20/87 04/20/87 04/ ' /87

Mr. J. P. O'Reilly Georgia Power Company Vogtle Electric Generating Plant CC:

Mr. L. T. Gucwa Resident Inspector Chief Nuclear Engineer Nuclear Regulatory Commission Georgia Power Company P. O. Box 572 P.O. Box 4545 Waynesboro, Georgia 30830 Atlanta, Georgia 30302 Mr. Ruble A. Thomas Depoish Kirkland, III, Counsel Vice President - Licensing Office of the Consumers' Utility Vogtle Project Council Georgia Power Company / Suite 225 Southern Company Services, Inc. 32 Peachtree Street, N.W.

P.O. Box 26P5 Atlanta, Georgia 30303 Birmingham, Alabama 35202 James E. Joiner Mr. Paul D. Rice Troutman, Sanders, Lockerman, Vice President & Project Director & Ashr. ore Georgia Power Company Candler Buildino Post Office Box 299A, Route 2 127 Peachtree Street, N.E.

Waynesboro, Georgia 30830 Atlanta, Georgia 30303 Danny Feig Mr. J. A. Bailey 1130 Alta Avenue Project Licensing Manager Atlanta, Georgia 30307 Southern Company Services, Inc.

P.O. Box 2625 Carol Stangler Birminoham, Alabama 35202 Georgians Againn Nuclear Energy 425 Euclid Terrace Ernest L. Blake, Jr. Atlanta, Georgia 30307 Bruce W. Churchill, Esc.

Shaw, Pittman, Potts ano Trowbridge 2300 N Street N.W.

Washington, D. C. 20037 Mr. G. Bockhold, Jr.

Vogtle Plant Manager Georgia Power Company Route 2, Box 299-A Waynesboro, Georgia 30830 Regional Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta Street, N.W., Suite 2900 Atlanta, Georgia 30323 Mr. R. E. Conway Senior Vice President and Project Director Georgia Power Company Rt. 2, P. O. Box 299A Waynesboro, Georgia 30830

. MEETING

SUMMARY

DISTRIBUTION Docket File NRC Participants NRC PDR M. M111er L PDR T. Sullivan NSIC K. Wichman PRC System S. Hou .

PD#II-3 Rdg S. Lee Project Manager M. Miller M. Duncan OGC-Bethesda ACRS (10)

FMiraglia Glainas OTHERS 4

bec: Licensee & Service List 1

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. ENCLOSURE 1 PARTICIPANTS hRC SOUTHERN COMPANY SERVICES

-M. Miller O. Batum T. Sullivan K. Kopecky K. Wichman S. Hou WESTINGHOUSE S. Lee W. Guer in NUS CORP A. Ayoob J. Whiteman S. Savage S. Swamy K. Chang

VOGTLE ELECTRIC GENERATING PLANT UNIT 2 STEAM GENERATOR SNUBBER REDUCTION AND LEAK BEFORE BREAK APPLICATION TO AUXILIARY LINES l GEORGIA POWER COMPANY MEETING WITH THE U. S. NRC APRIL 17, 1987

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GEDRGIA POWER COMPANY INTENT o TO PROVIDE TECHNICAL BASIS FOR VDGTLE UNIT 2 REDUCTION OF STEAM GENERATOR SNUBBERS FROM FIVE TO TWO PER STEAM GENERATOR ELIMINATIDN DF PIPE BREAKS ON 10" AND LARGER PIPING FOR SURGE, RHR AND ACCUMULATOR LINES USING LEAK BEFORE BREAK TECHNOLOGY o TO SUBMIT TO THE NRC FSAR CHANGES ON STEAM GENERATOR UPPER SUPPORT REDESIGN o TO SUBMIT GDC-4 EXEMPTION REQUEST FOR SURGE, RHR AND ACCUMULATOR LINES o TO RECEIVE NRC APPROVAL FOR THE ABOVE SUBMITTALS J

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PRIOR PLANT EXPERIENCE o PRIMARY COOLANT LOOP AND EQUIPMENT SUPPORT REDESIGN SURRY UNIT 1 AND 2 (APPROVED)

CRYSTAL RIVER (APPROVED)

NORTH ANNA UNITS 1 AND 2 (UNDER REVIEW) l I

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THREE OTHER PLANTS (ANALYSES IN PROGRESS)

I o LEAK BEFORE BREAK APPLICATION SOUTH TEXAS UNIT 2 (UNDER ACTIVE REVIEW)

BEAVER VALLEY UNIT 2 (FINAL STAGE OF REVIEW)

-- CATAWBA U;aIT 2 (UNDER REVIEW)

MCGUIRE UNITS 1 AND 2, CATAWBA UNIT 1 (ANALYSIS COMPLETED) 2

4

SUMMARY

OF BENEFITS o ALARA IMPROVEMENTS

'I o INCREASED ACCESSIBILITY AND PERSONNEL SAFETY o IMPROVEMENT IN PLANT RELIABILITY

• o REDUCTION IN PLANT INSPECTION AND MAINTENANCE COSTS o REDUCTION IN ENGINEERING AND CONSTRUCTION COSTS 9

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^ RCL/ SUPPORT MS & FW LINE PIPlNG AN WIS S WLYSIS j & QUALIFICATION 6 6 6 RCL LBB >

LOADS FOR LBB CONF 1RMATION AND CONCRETE LOAD EVALUATION INTERFACE LOAD -< QUALIFICATION 1 QUAUF1 CATION h h LBB EVALUATION > REC NC IA ON Ls

STEAM GENERATOR SNUBBER REDUCTION PROGRAM o SCOPE ESTABLISH REVISED SNUBBER CONFIGURATION PERFORM RCL/ SUPPORT STRUCTURAL ANALYSIS 1

PROVIDE INPUT TO AUXILIARY LINE PIPING STRESS ANALYSIS PROVIDE INPUT TO AUXILIARY LINE LBB APPLICATIONS OBTAIN NRC APPROVAL APPLY RESULTS TO VOGTLE UNIT 2 i

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STEAM SENERATOR SNUBBER REDUCTION o CRITERIA NO CHANGE TO FSAR CRITERIA EIGHT (B) BREAKS ON THE RCL ELIMINATED MAIN STEAM LINE AIB'S ELIMINATED MS AND FW LINE TERMINAL END BREAKS INCLUDED IN RCL ANALYSIS ,

THREE LARGEST BRANCH NOZZLE BREAKS INCLUDED IN RCL ANALYSIS I

TWO (2) SNUBBERS AT STEAM GENERATOR UPPER SUPPORT WILL BE ADEQUATE 2X DBE AND 4% SSE DAMPING USED FOR RCL ANALYSIS

-- ASME SECTION III CODE, SUBSECTIDN NB FOR PIPING

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-- ASME SECTION III CODE, SUBSECTION NF FOR SUPPORT QUALIFICATION LOOP LBB WILL BE CONFIRMED WITH NEW LOADS 1

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6 STEAM GENERATOR SNUBBER REDUCTION o METHODOIDGY DETERMINE REQUIRED NUMBER OF SNUBBERS RETAIN SNUBBER I4 CATIONS 2 AND 4 TO MAXIMIZE UPPER SUPPORT STIFFNESS RETAIN SNUBBER LOCATIOliS 2 AND 4 TO MINIMIZE RING GIRDER STRESSES USE SNUBBER STIFFNESS BASED ON TEST DATA LOOP ANALYSIS METHOD TO BE IDENTICAL TO UNIT #1 EXCEPT FOR STIFFNESS CHANGE SNUBBERS TO BE INSTALLED WITHIN TOLERANCE TO ENSURE I

CONSTRUCTION RELIABILITY N

ONE ORGANIZATION TO BE TOTALLY RESPONSIBLE FOR DESIGN / ANALYSIS OF RCL PIPING / SUPPORT TO ENSURE ENGINEERING RELIABILITY INDEPENDENT REVIEW BY LAWRENCE LIVERMORE NATIONAL LABORATORY CONFIRMED RELIABILITY OF WESTINGHOUSE RCL DESIGN AND CONSTRUCTION p

BTEAM GENERATOR SNUBBER REDUCTION o EXPECTED ANALYTICAL RESULTS

-- STEAM GENERATOR UPPER SUPPORT LOAD CHANGE l WILL BE SMALL

-- RCL SEISMIC AND LOCA STRESS CHANGES WILL BE SMALL l

-- EQUIPMENT NOZZLE AND SUPPORT PAD LOADS CHANGES WILL I BE SMALL

-- MAIN STEAM LINE PIPING DYNAMIC STRESS WILL BE AFFECTED DUE TO CHANGE OF STEAM GENERATOR MOTIONS NO IMPACT ON DEADWEIGHT AND THERMAL DESIGN OF RCL ll

STEAM SENERATOR SNUBBER REDUCTION o BENEFITS ALARA IMPROVEMENT VISUAL INSPECTION AND PREVENTIVE MAINTENANCE SAVINGS FUNCTIONAL TESTING SAVINGS MATERIAL SAVINGS INSTALLATION SAVINGS

-- IMPROVEMENT IN PLANT RELIABILITY

LEAK-BEFORE BREAK EVALUATION OF HIGH ENERGY. PIPING IN VOGTLE UNIT 2 SCOPE o PRESSURIZER SURGE LINE (16"/14") - LOOP 4 o RHR SUCTION LINES FROM HOT LEGS (12") - LOOPS 1 & 4 i

o ACCUMULATOR INJECTION LINES (10") - LOOPS 1, 2, 3, &4 1

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POSTULATE INITIAL SURFACE FLAWS DETERMINE FINAL CRACK SIZE BASED ON DESIGN TRANSIENTS DEMONSTRATE THAT FINAL CRACK DEPTH IS ACCEPTABLE o LEAK RATE PREDICTIONS POSTULATE THROUGH-WALL FLAWS CALCULATE CRACK OPENING AREA RESULTING FROM NORMAL OPERATING CONDITION LOADS CALCULATE LEAK RATE DETERMINE FLAW SIZE YIELDING DETECTABLE LEAK RATE.

(" LEAK SIZE FLAW")

u CRACK STABILITY ANALYSIS MARGIN ON FLAW SIZE MARGIN ON LOADS i

STABILITY CRITERIA GLOBAL FAILURE Mapp < M1im LOCAL FAILURE J < Jin i

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ACCEPTABILITY OF MARGINS o FINAL CRACK DEPTH BASED ON FCC ANALYSIS <60% OF WALL THICKNESS o MARGIN OF A FACTOR OF 10 BETWEEN THE CALCULATED LEAK RATE AND THE PLANT LEAK DETECTION CAPABILITY o MARGIN OF A FACTOR OF 2 BETWEEN THE LEAKADE SIZE FLAW AND THE CRITICAL FLAW o MARGIN OF A FACTOR OF/2"ON APPLIED MAXIMUM LOAD (NORMAL PLUS SSE)

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ANALYSIS o APPLIED LOADS o MATERIAL CERTS, MATERIALS STRENGTH AND TOUGHNESS DATA o IDENTIFY GOVERNING LOCATION o FCG ANALYSIS o LEAK RATE CALCULATIONS USING NORMAL OPERATING LOADS LEAKAGE SIZE FLAW o FLAW STABILITY ANALYSIS USING (NORMAL + SSE) LOADS.

DEMONSTRATE MARGIN ON FLAW SIZE o FOR LEAKAGE SIZE FLAW DEMONSTRATE STABILITY FOR E (NORMAL + SSE LOADS) o ABSENCE OF SIGNIFICANT: WATER HAMMER; HIGH OR LOW CYCLE FATIGUE; FLOW STRATIFICATION; INTERGRANULAR STRESS CORROSION CPACKING; AND EROSION / CORROSION 20

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e EXPECTED RESULTS FCG WILL BE WITHIN ACCEPTABLE LIMITS THE FLAWS WILL REMAIN STABLE BOTH FROM LOCAL AND GLOBAL STANDPOINT LEAK RATES ARE DETECTABLE WITH EXISTING MONITORING SYSTEMS BASED ON REG. GUIDE 1.45 1

MECHANISTIC CONSIDERATIONS SHOW THAT GUILLOTINE BREAKS ARE NOT POSSIBLE

d BENEFITS o REDUCTION IN MAN-REM EXPOSURE o IMPROVEMENT FOR OPERATION, INSPECTION AND MAINTENANCE o ELIMINATION OF PIPE WHIP RESTRAINT INSTALLATION AND GAP SHIMMING o REDUCTION OF EFFORT IN HAZARD STUDY o IMPROVEMENT IN CONSTRUCTION AND STARTUP SCHEDULE cD

4 I

SUMMARY

KEY MILSTONE DATES FOR FUTURE ACTIVITIES:

o PROGRAM INITIATION MARCH, 1987 o LETTER TO NRC ON TECHNICAL DESCRIPTION AND SCHEDULE 5/1/87 o NRC CONCURRENCE / TECHNICAL APPROVAL 6/1/87 o STEAM GENERATOR SNUBBER REDUCTION NRC PRESENTATION OF RESULTS 6/1/87 SUBMITTAL OF FSAR CHANGES 7/1/87 NRC APPROVAL 9/1/87 o LBB APPLICATION TO AUXILIARY LINES SURGE LINE LBB PRESENTATION 6/1/87 SURGE LINE LBB WCAP REPORT 7/1/87 RHR & ACCUMULATOR LINE LBB PRESENTATION 8/15/87 RHR & ACCUMULATOR LINE LBB WCAP REPORT 10/1/87 NRC APPROVAL FOR EXEMPTION REQUEST ON SURGE RHR AND ACCUMULATOR LINES 12/1/87 N3

. - . . .-- _- .