ML20209F239

Recirculation,Rhr & Reactor Water Cleanup Sys Piping Weld Joint Insp/Mitigation Program for 1985 Maint/ Refueling Outage

ML20209F239
Person / Time
Site:	Hatch
Issue date:	07/01/1985
From:	GEORGIA POWER CO.
To:
Shared Package
ML20209F230	List: ML20209F224 ML20209F239 ML20209F254
References
PROC-850701, TAC-59029, NUDOCS 8507120419
Download: ML20209F239 (7)

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ATTACHMENT 1 Hatch Unit 1 Recirculation, RFR, and RWCU Systems Piping Weld Joint Inspection / Mitigation Program 1985 Maintenance / Refueling Outage w

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• e TABLE OF CONTENTS

1.0 INTRODUCTION

2.0 PROPOSED INSPECTION SCOPE

' 3.0 INSPECTION PROCEDURE APO PERSONEL QUALIFICATIONS 4.0 ~ INSPECTION OF WELD OVERLAYS 5.0 CRITERIA FOR FLAW EVALUATION AND WELD OVERLAY REPAIR 6.0 CRITERIA FOR APPLICATION OF INDUCTIVE EATING STRESS IMPROVEMENT 7.0 LEAK DETECTION Af0 LEAKAGE LIMITS FOR EXT FUEL CYCLE 8.0 INSPECTION / MITIGATION PLANS SUWARY 07/01/85

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1.0 ' INTRODUCTION

This Attachment' to ' Georgia -Power -Company- (GPC) letter NEU-85-477

. provides a . description of the proposed program for the mitigation of IGSCC in and inspection of the main recirculation and other reactor pressure boundary stainless steel piping systems during the 1985 maintenance / refueling outage at Hatch Ur11t 1. The only piping systems involved are the Reactor Recirculation (Recirc), Residual Heat' Removal (RHR), and Reactor Water -Cleanup (RWCU) systems. . Included in the

< proctam description are GPC's criteria for weld selection, ultrasonic examination,~ flaw evaluation, and aoplication of IHSI and weld joint overlays. In addition, leak detection and leakage limits for the next fuel cycle are discusced.. A discussion of- the Attachment'l items

' relative to the proposed inspection program follows.

- 2.0 PROPOSED INSPECTION SCOPE GPC has elected to examine 100% of the 130 intergranular stress corrosion cracking (IGSCC)-sensitive piping welds in those sizes of

~p iping in the Recirc, RHR, and RWCU systems required by the ASME Section XI Code -to be volumetrically examined. Had this conservative approach not been taken, the required ' inspections for the 1985 maintenance / refueling outage at Hatch Unit 1 per NRC Generic Letter 84-11 would have. included a sample size of only fifty-three (53) piping welds composed from the classes of welds listed below:

Available Percent in Number of Result-Condition Population Initial Sample ant Examinations Overlays of repaired 23 100% 23 piping welds with IGSCC-Unrepaired piping 4 100% 4 welds with IGSCC Previously inspected 103 20% 26 piping welds (in

.Recire,)RHR, systems with and no in- RWCU dications of IGSCC Previously'uninspected 0* 20% 0

-piping welds (in Recire, RHR,' and RWCU Systems) 4 Total welds 130 53

• A one-hundred percent (100%) inspection of the stainless steel piping welds in those sizes of piping in the Recirc, RHR, and RWCU systems required by -the ASE Section- XI Code to be volumetrically examined was conducted.dcring the previous (1984) maintenance / refueling outage.

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• - 3.0; INSPECTION PROCEDURE Af0 PERS0 PEEL QUALIFICATION The . stainless steel piping weld ultrasonic examinations to be performed

!during the 1985 maintenance / refueling outage at Hatch Unit 1 will be conducted using -a Southern Company Services (SCS) procedure - similar to that which was previously ' qualified at Battelle-Columbus Laboratories

. (BCL) in 1982 pursuant to the requirements of PRC I&E Bu11etin. 82-03, Rev. 1.- Since the inspection of the stainless steel piping welds ~ in 1982 at' Hatch thit 1, the procedure has.been revised slightly and .was successfully used in thel detection of IGSCClat Hatch Units 1 and 2

' during the 1984 .and .1983 - maintenance / refueling outages, .respectively.

The latest - approved revision of the procedure meets or. exceeds the originally BCL-qualified procedure, e.g., calibration requirements, recording requirements, etc.

With regard to personnel qualification, examination personnel will be qualified to -basic levels I, .II, and III in accordance with American Society for . Nondestructive Testing document SNT-TC-1A, as applicable.

Additionally, examination personnel will be demonstrated to be qualified to a level of competence commensurate with their functions.

Examiners involved in equipment setup or scanning operations will be trained . and - demonstrated proficient to assure . both their technical ability. and their ability to perform activities consistent with the

. principles of keeping radiation exposure as low as reasonably

, achievable (ALARA).

The process of qualification for those who will. perform evaluations will be that process presently in effect at the EPRI IOE Center.

Currently, there.are seven (7) Levels II and III SCS personnel who have

. qualified at that facility by practical demonstration. Examination

. personnel under contract to SCS who have qualified at the EPRI bOE

. Center in the detection and interpretation of IGSCC may also perform examinations. and evaluations, as appropriate. In addition, three (3) of the. aforementionedSCS personnel qualified in the detection and interpretation of IGSCC are also qualified in planar flaw sizing at the EPRI.POE-Center. Examination personnel'under contract to SCS who~have

< qualified at the EPRI NDE Center in planar flaw sizing may also perform such examinations and evaluations, as appropriate.

4.0. INSPECTION OF WELD OVERLAYS The_ existing 23 weld overlays in the proposed inspection program for the 1985 Hatch thit .1 maintenance / refueling outage will be

- ultrasonically examined to verify the integrity of both the weld overlay and the outer 1/4 T of the piping base material. For the six weld overlays which were applied during the 1982 maintenance / refueling outage, a 45-degree shear-wave ultrasonic examination will be performed since these< weld overlays were originally examined in this fashion. In addition, a high angle refracted longitudinal-wave' ultrasonic

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examination will be conducted on the six original weld overlays. For those weld overlays which were applied during the 1984 maintenance / refueling - outage, only a 70 degree refracted longitudinal-wave ultrasonic examination- will be conducted. Use of a high . angle refracted longitudinal-wave technique has proven to be effective in recent EPRI POE Center tests on weld overlays. It has been shown through such tests that crack-like indications can be reliably detected and sized in the outer 1/4 T of the weld overlaid pipe wall and in the weld overlay itself. Any new weld overlays will be ultrasonically examined in a manner consistent with ASE Code,Section V or the EPRI NDE Center technique. In addition, for the existing weld overlays and any new weld overlays applied, a liquid penetrant examination will be conducted on the weld overlay and 1" of base material on either side of the weld overlay.

5.0 CRITERIA FOR FLAW EVALUATION APO WELD OVERLAY REPAIR Flaw evaluation for weld overlay . repair, if required during the 1985 Hatch Unit 1 maintenance / refueling outage, will be performed to criteria consistent with those specified in Attachment 2 of WC Generic Letter 84-11.

Should any new unacceptable, crack-like indications or any significant growth of old IGSCC cracks be observed during the inspection, information concerning the following will be submitted to PRC for review and approval:

o Flaw evaluations, and any re-evaluation; and o Weld overlay design and analyses techniques, if required.

6.0 CRITERIA FOR APPLICATION OF INDUCTIVE WATING STRESS IMPROVEMENT (IHSI)

Those welds which do not require weld overlay repair per the criteria of WC Generic Letter 84-11 will be evaluated for application of IHSI.

If the flaw evaluation indicates that IHSI is a viable mitigation technique for a given weld, tha't is the weld is free of crack-like indications or such indications are sufficiently shallow that the crack tip is within _ the zone of compressive residual stresses following treatment, then IHSI will be applied. Otherwise mitigation will be applied by weld overlay, albeit not required by the criteria of PRC Generic Letter 84-11. Thus, upon completion of this program, each weld will have had the potential for IGSCC mitigated by either IHSI or weld overlay.

7.0 LEAK DETECTION AND LEAKAGE LIMITS FOR PEXT FUEL CYCLE By letters dated February 10 and 11, 1983, GPC proposed Technical Specifications changes to augment then existing reactor coolant leakage detection requirements. NRC reviewed and approved the Technical Specification changes as discussed in the Haten Unit 1 Safety Evaluation Report dated February 11, 1983. The changes meet the intent of the' leak detection and leakage limits discussed in Attachment 1 to tRC Generic Letter 84-11.

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7.0 ' LEAK' DETECTION. APO LEAKAGE LIMITS FOR NEXT ' FUEL-CYCLE (continued):-

m JIn iaddition to. the above, a visual examination- for -leakage of the ,

reactor 1 coolant piping will - be performed during each plant; outage in-which' the primary containment is deinerted. ~ The examination will be

performed consistent with the . requirements of IWA-5241 and IWB-5242. of the 1980 -Edition = of. the . ASME Section XI Code. The system boundary 1 subject to this : examination will be in accordance with IWA-5221. This. l examination .is consistent with that identified in Attachment -1 of WC LGeneric! Letter ~84-11. ,

8.0 INSPECTION / MITIGATION PLANS SlM4ARY.

The

following is provided to summarize GPC's proposed IGSCC corrective

, program for-the 1985 maintenance / refueling outage at Hatch Unit 1:

1. While WC Generic Letter .84-11 weld examination guidance would have -

.resulted in an initial sample size of 53 welds, GPC has elected to

examine ~ '100% of the IGSCC-sensitive piping welds in those sizes of piping :in the Recirc, RW, and RWCU systems required by the ASME Section XI Code to be volumetrically, examined.

2. Qualification of ultrasonic. examination personnel. will be in accordanca with W C requirements (i.e., MC I&E Bulletin 83-02).

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3.. The existing weld overlays in the proposed inspection program will

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be ultrasonically examined to verify the' integrity of both the weld overlay and outer.1/4.T of the piping base material.

4. The original six. weld overlays will be ultrasonically examined using

.both a 45 degree shear-wave and a high angle refracted -

longitudinal-wave technique. The remaining existing weld overlays will be examined .using only the 70 degree - refracted longitudinal-wave technique.

5. Use ~ of a high angle refracted longitudinal-wave ultrasonic i examination technique has proven to' be effective in .recent EPRI POE Center tests on weld overlays. It has been shown'through such tests that crack-like indications = can be reliably' detected and sized- in the outer :1/4 T of the overlaid pipe wall and in the weld overlay

.itself.

6. Any new weld overlays will be- ultrasonically examined to verify the integrity of the weld overlay and its bond to the piping base material in a manner . consistent with ASME Code,Section V or -the EPRI f0E Center-technique.

7. In addition to . ultrasonic examination, for the existing ' weld overlays and any new weld overlays applied, a liquid penetrant

. examination will be. conducted. on the weld overlay and la of base 7 material =on either side of the weld overlay.

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8.0 INSPECTION / MITIGATION PLANS SLNMARY (continued):

8. Flaw evaluation and weld overlay repair, if required, will be performed to criteria consistent with those specified in NRC Generic Letter 84-11.

9. Subject welds which are free of crack-like indications or have crack-like indications appropriate for treatment by residual compressive stress patterns will have IHSI applied. All other subject welds will be repaired / treated by weld overlay.

10. Existing Plant Technical Specifications for reactor coolant leakage detection meet the intent of the leak detection and leakage limits specified in WC Generic Letter 84-11.

11. In addition to the existing reac*.or coolant leakage detection Technical Specifications, a visual examination for leakage of the reactor coolant piping will be performed during each plant outage in which the primary containment is deinerted. This examination will be consistent with that identified in NRC Generic Letter 84-11.

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