ML20211K638

Forwards Comments in Response to NRC 860424 SER Re Repair & Insp of Reactor Coolant Piping Sys & Core Spray Spargers Conducted During Fall 1985 Maint/Refueling Outage

ML20211K638
Person / Time
Site:	Hatch
Issue date:	06/23/1986
From:	Gucwa L GEORGIA POWER CO.
To:	Muller D Office of Nuclear Reactor Regulation
References
2784N, SL-882, TAC-56540, TAC-60943, NUDOCS 8606300199
Download: ML20211K638 (7)

Text

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Georgia Power Company 333 Piedrnont Avenue Atlanta, Georgia 30308 Telephone 404 526-6526 Mailing Address:

Post Of hce Box 4545 Atlanta, Georg:a 30302 Georgia Power

- L T. Gucwe tw s<Mhem eearc synem Manager Nuclear Safety and ucensing SL-882 2784N

{ June 23, 1986 Director of Nuclear Reactor Regulation i Attention: Mr. D. Muller, Project Director j BWR Project Directorate No. 2

Division of Boiling Water Reactor Licensing i U.- S. Nuclear Regulatory Commission Washington, D. C. 20555 i

NRC DOCKET 50-321 i OPERATING LICENSE DPR-57 1 EDWIN I. HATCH NUCLEAR PLANT UNIT 1 RESPONSE TO NRC SAFETY EVALUATION REPORT RELATING t TO INSPECTION AND REPAIR OF REACTOR COOLANT PIPING SYSILMS AND CORE SPRAY SPARGERS i

Gentlemen:

By letter dated April 24, 1986, the NRC provided Georgia Power Company

(GPC) with a safety evaluation report (SER) relating to the inspection and i

repair of reactor coolant piping systems and core spray spargers performed during the Fall 1985 maintenance / refueling outage at Hatch Unit 1.

, Following review of the aforementioned NRC letter and SER, we believe that it is necessary to respond to the NRC transmittal because of several inaccuracies and recommendations contained therein. It should be noted that

! our enclosed comments will not affect the conclusions reached in the SER e

! with regard to the inspections and repairs performed during the subject outage and are meant primarily to clarify activities performed.

i Should you have any questions in this regard, please contact this office at any time.

I Sincerely, I

i L. T. Gucwa i JAE/mb i

Enclosure c(w): Georgia Power Company U. S. Nuclear Regulatory Commission Mr.s. P. O'Reilly Dr. J. N. Grace, Regional Administrator Mr. J. T. Beckham, Jr. Senior Resident Inspector Mr. H. C. Nix, Jr.

GO-NORMS

! B606300199 860623 PDR G

ADOCK 05000321 PDR 40 Of ff

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Georgia Power m.* k ENCLOSURE GEORGIA POWER C0W ANY COMMENTS IN RESPONSE TO THE NRG APRIL Z4,1986, LLIItR AND SAFETY EVALUATION REPORT CONGERNING REPAIR AND INSPtGTION AGTIVITIES CONDUCTED DURING THE i HATCH UNIT 1 1985 REFUELING OUTAGE l Georgia Power Company (GPC) wishes to offer the following coments relative l to the safety evaluation report (SER) on the inspection and repairs of l reactor coolant piping systems and core spray spargers conducted during the l Fall 1985 maintenance / refueling outage at Hatch Unit 1. Our comments are

, provided according to SER section.

i

SECTION 1.0 This introductory section of the SER incorrectly noted that a total of 143 welds susceptible to intergranular stress corrosion cracking (IGSCC) was

, ultrasonically inspected during the Hatch Unit 1 outage and consisted of 125 1

welds in the recirculation (Recirc) system, 12 welds in the Residual Heat r Removal (RHR) system, and 6 welds in the Reactor Water Cleanup (RWCU) l system. The SER should have noted that 110 welds in the Recirc system and j 21 accessible welds in the RWCU system were ultrasonically examined. The references in the SER to the total number of welds and the number of RHR welds ultrasonically examined were correct. The quantity of welds (by size i and system) was specifically addressed in our March 10, 1986, submittal.

i With regard to the performance of the induction heating stress improvement (IHSI), the SER should be noted that 107 welds were successfully treated with IHSI, including 12 welds having reportable indications. Originally, l 111 welds were treated with IHSI; however, post-IHSI ultrasonic examination indicated that 4 welds required repair by weld overlay following IHSI. This was specifically addressed in our March 10, 1986, submittal.

SECTION 1.1 This section of the SER pertained to the ultrasonic examination for IGSCC and noted that the examinations were performed for GPC by qualified personnel from Southern Company Services (SCS). To more accurately reflect the performance of the examinations, the SER should have noted that the examinations were performed by SCS and its contractors. The use of contractors was specifically noted in our March 10, 1986 submittal.

SECTION 1.2 Section 1.2 of the SER pertained to the results of the inspection. This section noted that 20 additional welds, consisting of four 6-inch RWCU welds, nine 12-inch Recire welds, five 28-inch Recirc welds, one 12-inch 2784N i

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Georgia Powerkh ENCLOSURE (Continued)

GEORGIA POWER C0WANY COMMENTS IN RESPONSE TO THE NRG APRIL 24, 1986 LLIIER AND SAFETY EVALUATION REPORT CONGERNING REPAIR AND INSPECTION ACTIVITIES CONDUCTED DURING THE HATCH UNIT 1 1985 REFUELING OUTAGE SECTION 1.2 (Continued)

Recirc safe end-to-nozzle weld, and one 20-inch RHR weld, were observed during the subject outage to have crack-like indications. Please be advised that 22 additional welds were observed to have reportable indications. The breakdown by size and system provided in the SER is correct except that seven 28-inch Recirc welds were observed to have reportable indications.

With regard to the one 12-inch Recirc safe end-to-nozzle weld, the SER implies that the weld was cracked, and this most assuredly was not the case. The safe end-to-nozzle weld in question, 12BR-C-5, had a small subsurface lamination (not connected to the I.D. of the component) and is of Code allowable size. In addition, a statement in this section of the SER implies that both circumferential and axial cracks were observed in the welds having reportable indications, including the 12-inch Recirc safe end-to-nozzle weld. Each of these welds did not have both circumferential and axial cracks as the SER implies; however, each weld, with the exception of the safe end-to-nozzle weld as discussed above, had circumferential and/or axial crack-like indications but not necessarily both. The worst circumferential cracking was observed in RWCU weld RWCV-6-0VT-5, not RWCU-6-0VT-50, since no such weld exists. Coments relative to through-wall

. axial cracks observed in Recirc weld 12BR-B-3 following the IHSI treatment could be misconstrued to mean that the IHSI was the cause of the cracking.

It is likely that the axial indications were already present and were not observed during the pre-IHSI ultrasonic examination of weld 12BR-B-3, .since axial indications at times are difficult to detect. The axial indications were sufficiently large (depth-wise) such that they apparently penetrated through the wall when IHSI was applied to weld 12BR-B-3 This is not uncomon for deep axial cracks when performing IHSI. Finally, relative to this section of the SER, RHR weld 248-R-12, an unflawed weld which had an overlay applied to facilitate inspection of the subject weld joint, was also observed to have small lack-of-fusion indications in the weld overlay. The lack-of-fusion indications in the weld overlay of RHR weld 24B-R-12 were specifically discussed in our meeting with the NRC staff on March 18, 1986, and subsequently in our letter SL-569, dated May 2,1986 As a result, the statement in the SER indicating that all of the lack-of-fusion indications were reported to be located in the first two layers of the overlay may not be valid for all three welds (i.e. , 28A-12, 288-4, and 24B-R-12) having lack-of-fusion indications in the weld overlay.

SECTION 1.3 No comments are necessary relative to this section of the SER.

2784N '

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Georgia Powerkh ENCLOSURE (Continued)

GEORGIA POWER COMPANY COMMENTS IN RESPONSE TO THE NRC APRIL 24, 1986, LElitR AND SAFETY EVALUATION REPORT CONCERNING REPAIR AND INSPECTION ACTIVITIES CONDUCTED DURING THE HATCH UNIT 1 1985 REFUELING OUTAGE SECTION 1.4 This section of the SER pertained to flaw evaluation and weld overlay design. There is an inconsistency between this section and Section 1.2 of the SER relative to the number of welds showing crack-like indications (i.e., 21 vice 20 welds). Please refer to our comments above in response to Section 1.2 of the SER concerning the number of welds having crack-like (i.e., reportable) indications and welds showing lack of fusion in the weld i

overlay.

SECTION 1.5 No comments are necessary relative to this section of the SER.

SECTION 2.0 No comments are necessary relative to this section of the SER.

SECTION 2.1 No comments are necessary relative to this section of the SER.

SECTION 2.2 This section of the SER pertained to unrepaired welds. We take exception to the choice of terms utilized where the NRC concludes that the 12 unrepaired l (emphasis added) welds can be safely operated for one more fuel cycle of 18

months, since the Code design safety margins would continue to be l maintained. The term "unrepai red" implies that nothing was done to the

' respective welds to mitigate any additional cracking and this simply was not the case, since IHSI was performed on the subject welds during the outage.

In the conclusion statement of this SER section, it would have been more appropriate to refer to the subject 12 welds as having crack-like indications which were treated with IHSI. Effectively, IHSI of the subject welds constituted their repair.

j 2784N F00775

. Georgia Powerkh ENCLOSURE (Continued)

GEORGIA POWER C0lfANY COW 4ENTS IN RESPONSE TO THE NRG APRIL Z4,1986, LEIILR AND SAFETY EVALUATION REPORT CONCERNING REPAIR AND INSPECTION i 4

ACTIVITIES CONDUCTED DURING THE HATCH UNIT 1 1985 REFUELING OUTAGE d

SECTION 2.3 Section 2.3 of the SER pertained to weld overlay repairs. It should be noted that while there are 36 weld overlays at Hatch Unit 1, only 35 are the result of repairs, with the remaining 1 overlay having been applied to an unflawed weld solely to facilitate ultrasonic examination of the weld

! joint. The overlay applied to facilitate inspection and the reasons therefor were specifically discussed with the NRC staff in our meeting of i

' March 18,1986, and our submittals of March 10, 1986, and May 2,1986 As currently worded, the SER implies that all weld overlays applied at Hatch Unit 1 were as a result of repairs, and this is not the case. With regard to the statement in this section of the SER concerning weld overlays having lack-of-fusion indications, please refer to our comments in response to SER Section 1.2 i

SECTION 2.4 This section of the SER pertained to the core spray sparger inspection. It was indicated that the NRC still had some concerns regarding the long-term behavior of the existing cracks in one sparger "since a large portion of the cracks are not visible and of those pipes located in areas that cannot be fully inspected." To resolve those concerns, the NRC recommended in the SER that GPC perform an air bubble test at the next refueling outage to supplement the visual inspection required by NRC I&E Bulletin 80-13, i

" Cracking In Core Spray Spa rgers. " We indicated in our letter dated

' February 28, 1986, which responded to NRC staff questions, that such a test had not been performed when cracking was observed in the core spray sparger during the 1984 outage because GPC chose to take corrective measures which obviated the need for an air bubble test. We elected to install a clamping device on the affected sparger even though an analysis demonstreted that the l clamp was not necessary for continued safe operation with a 360-degree through-wall crack. This analysis was discussed in General Electric (GE) topical report NEDO-30825, " Core Spray Sparger Crack Analysis For Edwin I.

Hatch Nuclear Power Station, Unit 1," which was submitted to the NRC by our letter dated December 6, 1984 Exception is taken to the recommendation in the SER to perform an air bubble test during the next refueling outage to 4

supplement the visual examination of the core spray sparger and associated piping. Since the corrective measures taken are bounding for the worst-case cracking, it is not necessary to know if the actual crack is through-wall.

In addition, the core spray spargers and associated piping are visually inspected every refueling outage pursuant to the requirements of NRC 18E

Bulletin 80-13 and the results thereof reported to the NRC. Accordingly, it 2784N - . . . . .-.

GeorgiaPowerkh ENCLOSURE (Continued)

GEORGIA POWER C0WANY C0pmENTS IN RESPONSE TO THE NRG APRIL 24, 1986, LtIItR AND SAFLIT EVALUATION REPORT CONCERNING REPAIR AND INSPECTION ACTIVITIES CONDUGILD DURING THE HATCH UNIT 1 1985 REFUELING OUTAGE SECTION 2.4 (Continued) is our intention not to perform an air bubble test, since it is not warranted given the corrective measures taken by GPC and the results of the analysis performed by GE.

In addition, the SER indicated that the detailed inspection results of the visual inspection of the core spray spargers and associated piping should be submitted for NRC information within 2. weeks following completion of the inspection. Exception is taken to the recommendation in the SER that the detailed inspection results be provided to the NRC for the sole purpose of information within 2 weeks of the completion of the inspection. NRC I&E Bulletin 80-13 already addresses the reporting requirements for the visual inspection of the core spray spargers and associated piping. The Bulletin specifically indicates that: "Any cracking identifie'd in the core spray cooling system shall be reported to the Director of the appropriate NRC Regional Office within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of identification." The bulletin further specifically indicates that: "A written report of the results of the examinations including any corrective measures taken shall be submitted within 30 days of the completion of the examination to the Director of the NRC Regional Office with a copy to 5 NRC Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D. C.

20555." It is our opinion that the NRC is already adequately advised of the results of the visual inspection of the core spray spargers and associated l piping by the existing reporting requirements specified in NRC ISE Bulletin j 80-13 Therefore, it is .our intention not to provide an information report to the NRC within the requested 2-week timeframe following completion of the

! visual inspection. Reporting by GPC will continue to be made pursuant to I the existing reporting requirements specified in NRC I&E Bulletin 80-13 i

SECTION 3.0 l This section of the SER concluded that the repairs and inspections performed

[ during the Hatch Unit 1 1985 refueling outage were satisfactory and that the L unit could be safely operated in its present configuration for an 18-month i fuel cycle. The SER indicated that the NRC staff did have concerns relative l to the long-term growth of small IGSCC cracks that may be present in l stainless steel piping systems but were not detected during inspections l conducted during the subject outage. Therefore, it was requested that plans for inspection and/or modification of the Recirc and any other service sensitive austenitic stainless steel piping systems operating over 2000F 2784N 700775

ENCLOSURE (Continued)

Georgia Power d GEORGIA POWER COMPANY COMMENTS IN RESPONSE TO THE NRC APRIL 24, 1986, LElitR ARD SAFETY EVALUATION REPORT CONC 5hIdIkG REPAIR AND INSPECTION ACTIVITIES CONDUCTED DURING THE HATCH UNIT l 1985 REFUELING OUTAGE SECTION 3.0 (Continued) should be submitted for NRC review at least 3 months prior to the start of the next refueling outage. Reportedly, the NRC will issue NUREG-0313, Revision 2 in the near future and will require that all boiling water reactor licensees provide information to the NRC as to how the NUREG will be implemented for their respective facilities. Georgia Power Company currently intends for the response to NUREG-0313, Revision 2, to serve as the SER-requested submittal of our inspection and/or modification plans, since the intent of the SER would have been met. Should the NRC not issue NUREG-0313, Revision 2, for implementation prior to the next refueling outage at Hatch Unit 1, we will provide the SER-requested inspection and/or modification plans for NRC review within the timeframe specified in the SER.

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2784N TC3775