ML20059A588

Summary of 930923 Meeting W/Util in Rockville,Md Re Status of Activities Associated W/Crack Indications Observed in Unit 1 Core Shroud.List of Attendees & Slides Presented Encl

ML20059A588
Person / Time
Site:	Brunswick
Issue date:	10/19/1993
From:	Milano P Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 9310260403
Download: ML20059A588 (12)

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UNITED STATES j

NUCLEAR REGULATORY COMMISSION Adg( j f

WASHINGTON. D C. 20555-0001 s,,

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October 19, 1993 Docket No. 50-325 LICENSEE:

Carolina Power & Light Company FACILITY:

Brunswick Steam Electric Plant, Unit 1

SUBJECT:

MEETING

SUMMARY

OF SEPTEMBER 23, 1993 Representatives from Carolina Power & Light Company (the licensee) met with the Nuclear Regulatory Commission (NRC) staff on September 23, 1993, at the NRC offices in Rockville, Maryland.

The meeting was requested by the licensee to discuss the status of activities associated with crack indications observed in the Unit I core shroud. The attendees at the meeting are listed in and a copy of the slides presented at the meeting are given in.

The licensee described the inspection activities that had taken place during the previous month. Specifically, the licensee discussed the in-vessel inspection efforts with regard to the H3 and H4 welds.

The H3 weld joins the top guide support plate to the mid-portion of the shroud, and the H4 weld is' a circumferential weld between two shroud shell courses in the mid-core region.

The licensee indicated that a complete visual inspection of the inside diameter of the shroud above the lower core plate would be conducted. A description of the variable causal factors for the shroud cracking was presented. These factors included the electro-chemical corrosion potential in the various regions, the axial and circumferential fast neutron fluence distributions, and the fabrication orientations of the plate material.

Based on these factors and their variation among the different weld regions, the licensee presented their plans for performing the inspections of t,1e other shroud surface areas.

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The licensee also provided some details of the ultrasonic test (UT) equipment and supporting data acquisition system that would be used to characterize the crack dimensions. The UT equipment would incorporate 45 and 60 refracted longitudinal wave (RL) transducers. Measurements within each 12-inch long i

scanning segment would be performed at 0.05-inch increments.

The data acquisition would be via the General Electric (GE) SMART 2000 System.

The licensee discussed the development of core shroud analyses methodology and evaluation acceptance criteria. The licensee committed to provide this i

information to the NRC staff for review.

The NRC staff noted that the evaluation of specific weld areas should include sufficient crack characterization and an agreement on projected crack growth rates.

Finally, the licensee presented a brief discussion of crack mitigation options that j

were being pursued with assistance from GE and a description of the repair contingency for the crack in the H3 weld.

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The meeting concluded with a commitment to meet again when further information on the core shroud cracks, evaluation criteria, or design options become available.

[3f Patrick D. Milano, Senior Project Manager Project Directorate 11-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Enclosures:

1.

List of Attendees 2.

Slides Presented cc w/ enclosures:

See next page DISTRIBUTION w/ encl 1 & 2:

w/ Enclosure 1 only:

DocketxFile T. Murley/F. Miraglia 12-G-18 NRC/ Local PDRs J. Partlow 12-G-18 PD 11-1 R/F W. Russell 12-G-18 P. Milano 14-B-20 J. Wiggins 7-D-26 J. Strosnider 7-D-4 S. Varga 14-E-4 R. Hermann 14-C-7 G. Lainas 14-H-1 W. Koo 7-D-4 L. Phillips 8-E-23 E. Merschoff, R-II G. Hornseth 7-D-4 J. Johnson, R-II P. Anderson 14-B-20 R. Carroll, R-II ACRS (10)

OGC L. Plisco 17-G-21

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0FFICE LA:PD21:DRPE PM:PD21:DRPE AD M E NAME PAndektI/FU PDMilano SSB[jta [ [

DATE 10//7/95 10/i9 /93 10//T/93 0FFICIAL RECORD COPY DOCUMENT NAME: G:\\BRL'NSWIC\\BR9-23.MTS O l-2200~?

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a Mr. R. A. Anderson Brunswick Steam Electric Plant Carolina Power & Light Company Units 1 and 2 cc:

Mr. Mark S. Calvert Karen E. Long Associate General Counsel Assistant Attorney General Carolina Power & Light Company State of North Carolina Post Office Box 1551 Post Office Box 629 Raleigh, North. Carolina 27602 Raleigh, North Carolina 27602 Mr. Kelly Holden, Chairman Mr. Robert P. Gruber Board of Commissioners Executive Director Post Office Box 249 Public Staff - NCUC Southport, North Carolina 28422 Post Office Box 29520 Raleigh, North Carolina 27626-0520 Resident Inspector U.S. Nuclear Regulatory Commission Mr. H. W. Habermeyer, Jr.

Star Route 1, Post Office Box 208 Vice President-Southport, North Carolina 28461 Nuclear Services Department Carolina Power & Light Company.

Regional Administrator, Region II Post Office Box 1551 - Mail OHS 7 U.S. Nuclear Regulatory Commission Raleigh, North Carolina 27602 101 Marietta St., N.W., Ste. 2900 Atlanta, Georgia 30323 Mr. Dayne H. Brown, Director Division of Radiation Protection N.C. Department of Environmental, Commerce and Natural Resources Post Office Box 27687 Raleigh, North Carolina 27611-7687 Mr. J. M. Brown Plant Manager - Unit 1 Carolina Power & Light Company Brunswick Steam Electric Plant Post Office Box 10429 Southport, North Carolina 28461 Public Service Commission State of South Carolina Post Office Drawer 11649 Columbia, South Carolina 29211 Mr. C. C. Warren Plant Manager - Unit 2 Brunswick Steam Electric Plant-Post Office Box 10429 Southport, North Carolina 28461 P

September 23. 1993 Carolina Power & Licht Company Unit 1 Core Shroud Cracks Meetina list of Attendees t

G. C. Lainas NRR/DRPE P. D. Milano NRC/NRR/PD21 R. Hermann NRR/EMCB W. Koo NRR/EMCB G. Hornseth NRR/EMCB J. Medoff NRR/EMCB L. Banic NRR/EMCB P. M. Byron NRC/RII W. R. Campbell CP&L/NED R. E. Grazio CP&L/NED G. D. Miller CP&L - BRUNSWICK K. A. Harris CP&L/ Licensing V. Wagoner CP&L/NED S. Ranganath GENE G. M. Gordon GENE R. E. Smith SciTech R. L. Dyle SNC/BWROG h

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NRC PRESENTATION i

NRC / CP&L TECHNICAL MEETING CORE SHROUD Rockville, Maryland

_Ei September 23,1993

AGENDA m

OPENING REMARKS W. R. CAMPBELL i

a INVESSEL INSPECTIONS G. D. MILLER I

m PLANNED ANALYSES S.RANGANATH a

FUTURE ACTIVITIES R. E. GRAZIO G.GORDON G. D. MILLER s

CLOSING REMARKS W. R. CAMPBELL Y

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INVESSEL INSPECTIONS a

INSPECTIONS TO DATE e

initial inspections e

Expanded inspections a

RESULTS/ TRENDS e

Shroud Map e

Causal Factors a

AREAS REMAINING TO BE INSPECTED

a SHROUD CRACKING VARIABLE CAUSAL FACTORS i

WELD ECP FLUX END GRAIN AFFECTS REMARKS H1 HIGH LOW HIGH ON OD VISUAL ON ID AND OD H2 HIGH MEDIUM HIGH ON OD UT AND VISUAL ON OD H3 HIGH MEDIUM HIGH ON ID VISUAL AND UT ON ID VISUAL ACCESSIBLE OD H4 MEDIUM HIGH N/A VISUAL ID AND OD H5 MEDIUM HIGH N/A VISUAL ID ANG ~;D H6 LOW LOW HIGH ON OD VISUAL OD H7 LOW LOW N/A VISUAL OD H8

- LOW LOW N/A VISUAL ABOVE l-H9 LOW LOW N/A VISUAL ABOVE l-

ANALYSIS OF RESULTS m

SHROUD ANALYSIS METHODOLOGY e

H3. Weld e

Other Areas 1

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FUTURE ACTIVITIES s

REPAIR CONTINGENCIES e

Repair Design Basis e

Repair Design s

MITIGATION OPTIONS 1

e Based On Causal Factors l

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Hydrogen Water Chemistry e

Other. Options 1

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SUMMARY

s PROACTIVELY ADDRESSING ISSUE l

m EXTENSIVE SHROUD ID VISUAL EXAMS COMPLETED e

Results Confirming Causal Factors a

EXTENSIVE SHROUD OD VISUAL EXAMS CONTINUING e

Preliminary Results Continuing Trends a

REMAINING INSPECTIONS BASED ON CAUSAL FACTORS 3

l

SUMMARY

(CONTINUED) a BASIS FOR ANALYTICAL EVALUATION OF H3 AND OTHER SHROUD l

AREAS ESTABLISHED a

HYDROGEN WATER CHEMISTRY PROVIDES ADDITIONAL MARGIN e

H3 REPAIR CONTINGENCY

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