ML20215G435

Forwards Structural Integrity Assoc,Inc Rev 1 to SIR-87-014, Flaw Evaluation & Repair Design for Plant Ei Hatch Unit 1 Spring 1987 Outage & Inservice Insp Results of Stainless Steel Components & Corrective Actions Taken.Fee Paid

ML20215G435
Person / Time
Site:	Hatch
Issue date:	06/12/1987
From:	Gucwa L GEORGIA POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20215G438	List: ML20215G435 ML20215G458
References
RTR-NUREG-0313, RTR-NUREG-313 SL-2660, TAC-6477, TAC-64777, NUDOCS 8706230257
Download: ML20215G435 (8)

Text

.. Georgia Power Company .

333 Piedrnont Avenue .

Atlanta, Georgia 30308 Telephone 404 5264526 Mainng Address:

Post Office Box 4545 Atlanta, Georgia 30302 h Georgia Power L T. Gucwe tw wuthern eiwtnc system Manager Nuclear Safety and Licensing SL-2660 la29C X7GJ17-H790 June 12, 1987 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Hashington, D.C. 20555 PLANT HATCH - UNIT 1-NRC DOCKET 50-321 OPERATING LICENSE DPR-57 INSERVICE INSPECTION OF CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS - 1987 MAINTENANCE / REFUELING OUTAGE ~

Gentlemen:

Georgia _ Power Company (GPC) submits herein for your review the results of the inservice inspection of stainless steel components and the corrective actions taken for those welds found to have reportable indications during the Plant Hatch Spring 1987 maintenance / refueling outage. Enclosure 1 details (1) inspection procedures and personnel qualifications related to intergranular stress corrosion cracking (IGSCC) detection, IGSCC sizing, and weld overlay examination; (2) examination results; and (3) future plans. Enclosure '2 is a Structural Integrity Associates report on flaw evaluation and repair design for the Spring 1987 outage.

Pursuant to NRC requirements and to NUREG-0313 (Draft), Revision 2 GPC submitted to the NRC by letter SL-1951, dated February 20, 1987, our proposed inspection / mitigation program for the subject piping during the Spring 1987 maintenance / refueling outage. In followup, GPC participated in conversations with NRC staff members in order to clari fy details presented in the subject letter. The discussion and comments did not result in modification to the scope of the proposed inspection /

mitigation program.

However, during the performance of i n s e rv'. c e inspection, small crack-like indications were discovered in two 6-in.-diameter Reactor Hater Cleanup (RHCU) system Category C welds. Following the detection of the indications, the NRC (NRR and Region II) was contacted, and the scope of the inspection was expanded to include all remaining Category C RHCU system welds. Justification for the limited scope expansion and weld PDR overlay design was reported in GPC letter SL-2575, dated May 29, 1987.

8706230257 B70612 ADOCK 05000321 eon f[,

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GeorgiaPower d U. S. Nuclear Regulatory Commission June 12, 1987 Page Two Georgia Power Company plans to return the unit to power operation upon completion of the necessary repairs, analyses, baseline examinations, and successful completion of the hydrostatic test. Return to power operation is currently scheduled for on or about June 18, 1987.

He believe the results of the IGSCC inspection and repair activities, conducted during the outage, provide an adequate basis for the safe operation of the unit.

Pursuant to the requirements of 10 CFR 170, enclosed herein as payment of the application fee for review of the subject information is our check in the amount of one hundred and fifty dollars. Seven copies of this letter and enclosed reports are provided for your convenience.

If you have any questions regarding this matter, please contact this office at any time.

Sincerely, e

s

. T. Gutwa GKM/lc

Enclosures:

1. Inservice Inspection of Hatch Unit 1 Class 1 Stainless Steel Piping and Components - 1987 Maintenance / Refueling Outage. j

2. Structural Integrity Associates Report No. SIR-87-014, i Revision 1, " Flaw Evaluation and Repair Design for Plant E. I. i Hatch Unit 1 Spring 1987 Outage." {

3. Filing Fee - $150.00 '

c: (see next page) 1429C ,

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GeorgiaPower A U.,S. Nuclear Regulatory Commission June 12, 1987 Page Three c: -Georaia Power Comoany . .

Mr. J. P. O'Reilly, Sr. Vice President - Nuclear Operations Mr. J. T.'Beckham, Jr., Vice. President - Plant Hatch GO-NORMS U.S. Nuclear Reaulatory Commission. Washinaton. D.C.

Mr. L. P. Crockir, Licensing Project Managir - Hatch U.S. Nuclear Reaulatory Commission. Reaion II- ,

Dr. J. N.~ Grace, Regional Administrator Mr. P. Holmes-Ray, Senior Resident Inspector - Hatch 1429C

. room

- GeorgiaPowerA ENCLOSURE 1 PLANT HATCH - UNIT 1 NRC DOCKET 50-321  !

OPERATING LICENSE DPR-57 I INSERVICE INSPECTION OF HATCH UNIT 1 CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS 1987 MAINTENANCE /REFUff.ING OUTAGE TABLE OF CONTENTS 1.0 Introduction ,

2.0 1987 Maintenance / Refueling Outage Plans 3.0 -Inspection Procedures and Personnel Qualifications '

3.1 Procedures 3.1.1 IGSCC Detection 3.1.2 IGSCC Sizing 3.1.3 Held Overlay Examination l 3.2 Personnel Qualifications 3.2.1 IGSCC Detection 3.2.2 IGSCC Sizing.

3.2.3 Weld Overlay Examination 4.0 Examination Results 5.0 Future Plans l

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GeorgiaPower sh ENCLOSURE 1 (Continued)

INSERVICE INSPECTION OF HATCH UNIT 1 CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS 1987 MAINTENANCE / REFUELING OUTAGE

1.0 INTRODUCTION

1 During the inservice inspection conducted during the Spring 1987 maintenance / refueling outage at Hatch Unit 1, five welds in the stainless steel piping of the Class 1 Reactor Recirculation (Recirc) system and three welds in the Reactor Water Cleanup (RWCU) system were observed to have reportable indications. Georgia Power Company (GPC) hereby submits ;

information concerning the inservice inspection of welds in stainless steel piping and components, inspection procedures and personnel qualifications, weld repairs and flaw evaluations, and future plans.

2.0 1987 MAINTENANCE / REFUELING OUTAGE PLANS Pursuant to the NRC's letter of April 24, 1986, GFC submitted by letter SL-1951, dated February 20, 1987, our proposed program for the inspection of the recirculation and other reactor pressure boundary stainless steel piping during the 1987 maintenance / refueling outage at Hatch Unit 1.

Included in the GPC submittal was a technical justification for continued service with weld overlays. The proposed program included our criteria for weld selection, ultrasonic examination, flaw evaluation, IGSCC mitigation, and weld overlay repairs. The criteria were consistent with 1 the intent of corresponding applicable portions of NUREG-0313 (Draft),

Revision 2. Members of the NRC staff reviewed GPC's submittal of February 20, 1987, and verbally indicated that the proposed inspection program was acceptable.

During GPC's inspection of Class 1 stainless steel piping and components, small crack-like indications were discovered in two 6-in.-diameter RWCU system welds. Using the criteria presented in NUREG-0313 (Dra f t) ,

Revision 2, these welds were classified as Category C, which means that the welds had no identified IGSCC indications and that they had been treated with Induction Heating Stress Improvement (IHSI) during the 1985 Unit 1 maintenance / refueling outage. The original inspection plan, which was submitted to the NRC by GPC letter SL-1951 on February 20, 1987, called for the inspection of 52 percent of the Category C welds, including nine 6-in. RWCU system welds. Following the detection of the indications, the NRC (NRR and Region II) was contacted, and the scope of 1 the inspection was expanded to all remaining Category C welds in the RWCU system. The expanded scope (8 additional 6-in. welds) yielded an additional weld with small (less than 1-in. in length) circumferential and axial IGSCC-like indications. For each of the three welds discussed above, repairs were completed during this outage.

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GeorgiaPowerA ENCLOSURE 1 (Continued)-

INSERVICE INSPECTION OF HATCH UNIT 1 1 CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS 1987 MAINTENANCE /REFUELINA OUTAGE  !

3.0 INSPECTION PROCEDURES AND PERSONNEL QUALIFICATI0NS'

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3.1 Procedures

-3.1.1 IGSCC Detection Prior ' to the' 1985 Hatch Unit 1 maintenance / refueling outage, Southern Company Services (SCS) NDE' Procedure UT-H-400, Revision 5, .was used in the requalification process at the EPRI NDE Center as part of the NRC-mandated requalification program. During the 1987 Hatch Unit 1 maintenance / refueling outage, SCS NDE Procedure UT-H-400, Revision 7, was used. The changes that have been made to Procedure UT-H-400 since the 1905 maintenance / refueling outage increase the' detection sensitivity for small -indications. These changes include: increasing the. minimum transducer overlap. from 10 percent to 25 percent, broadening the screen range, and using slower scanning speeds.

3.1.2 IGSCC Sizing Southern' Company Services NDE planar flaw sizing Procedure UT-H-470, Revision 1, was developed, incorporating techniques and methods demonstrated and approved at the EPRI NDE Center for use at Plant Hatch.

3.1.3 Held Overlay Examination After SCS personnel successfully demonstrated the ability to examine weld overlays, SCS developed NDE Procedure UT-H-408, Revision 0, which incorporates the techniques and methods demonstrated and approved at the EPRI NDE Center for the post-surface finish improvement examination.

Prior to the 1987 Unit 1 maintenance / refueling outage, NDE procedure UT-H-408 was revised to incorporate the deviations used during the 1985 outage.

3.2 Personnel Oualifications i 3.2.1 IGSCC Detection 1

As required by the NRC, Levels II and III personnel performing ultrasonic l examinations and/or evaluations were requalified at the EPRI NDE Center for the detection of IGSCC.

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GeorgiaPower A ENCLOSURE 1 (Continued)

INSERVICE INSPECTION OF HATCH UNIT 1 CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS 1987 MAINTENANCE / REFUELING OUTAGE 3.2.2 IGSCC Sizing Level II or III personnel performing ultrasonic sizing of indications were qualified at the EPRI NDE Center in planar flaw sizing.

3.2.3 Held Overlay Examination As required by the NRC, Levels II and III personnel performing ultrasonic examinations and/or evaluations of weld overlays demonstrated the ability to successfully conduct the weld overlay examinations at the EPRI NDE Center. In addition, weld overlay examination personnel were IGSCC requalified. '

4.0 EXAMINATION RESULTS Flaw indications were identified at three weld locations in the RHCU system. These welds had been treated with IHSI during the last Unit 1 maintenance / refueling outage and subsequent post-IHSI UT inspections identified no IGSCC indications. The flaws discovered during the 1987 outage were relatively minor in nature and did not compromise the structural integrity of the respective welds at that time. Nevertheless, limited service weld overlay repairs to these three locations were made during the 1987 outage. Enclosure 2 provides details of the flaw indications, stress components, and weld overlay design, in addition to addressing the issue of weld overlay shrinkage. GPC plans to upgrade or replace those repairs during the next refueling outage.

Flaw indications were identified in the weld overlay material of two I welds in the recirculation system. The identified flaws appear to be traceable to fabrication defects in the weld overlay material itself (e.g., lack of fusion in the first overlay layer). The design function of the weld overlays is not impaired by the presence of the flaws. In j addition to the indications discussed above, three locations in the recirculation system (28-in. pipe) which had previously-reported flaws )

were determined to contain an additional flaw or had the characterization 4 of the flaw (s) indications revised. All five welds discussed above were shown to be acceptable without repair for another operating cycle. The three RWCU welds were repaired during this outage. A detailed description of the flaw evaluation and the repairs performed during the outage is presented in Enclosure 2.

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GeorgiaPower d 1

ENCLOSURE l'(Continued)

INSERVICE INSPECTION OF HATCH UNIT 1 CLASS 1 STAINLESS STEEL PIPING AND COMPONENTS J R 7 MAINTENANCE / REFUELING OUTAGE 4.0 EXAMINATION RESULTS (Continued)

Except for the relatively. minor indications identified in the eight welds mentioned, above, no reportable indications were identified. The inspection scope detailed in GPC's February 20, 1987, letter (SL-1951),

plus the scope expansion in the RHCU system piping, brought the total number of Category C, E, F, and G welds inspected to over 100.

5.0 FUTURE PLANS The RHCU system welds which were repaired during this outage with a limited ' service overlay will be either upgraded to a full structural overlay or otherwise replaced during the next scheduled Unit 1 maintenance / refueling outage.

Georgia Power Company has performed a mini-test of hydrogen injection on Hatch Unit 1. The test period has been extended and will continue during 4 the upcoming cycle. A permanent program for hydrogen water chemistry l will be evaluated based upon the results of this extended test and the ongoing industry experience.

Future inspection plans have not been formulated completely but will adhere to the requirements of NUREG-0313 (Draft), Revision 2. The plans include inspection of the remaining Category E and C welds which were not inspected during the 1987 outage. At least 60 days prior to the next regularly scheduled maintenance / refueling outage, GPC will provide the  !

NRC, for review and comments, the inspection program for the subject i Class 1 stainless steel piping and components. j l

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