ML20116E431

Submits Addl Info to Suppl 960521 Request for Relief to Portions of ASME Section Xi.Ltr Corrects Typographical Error in Summary of Relief Request & Relief Request Revs Also

ML20116E431
Person / Time
Site:	Grand Gulf
Issue date:	07/31/1996
From:	Hutchinson C ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GNRO-96-00088, GNRO-96-88, NUDOCS 9608050248
Download: ML20116E431 (3)

Text

l i Entirgy Opsrations,Inc.

l

~z"ENTERGY eo ezx7ce Port G,bson MS 39150 l Tel 601437 2800 j l ,

C. R. Hutchinson I vce Present l g

\ Opera' orc Grard G# tubar Staton July 31, 1996 l

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U.S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C. 20555 Attention: Document Control Desk i

Subject:

Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 AdditionalInformation for ASME Section XI Relief Request 1-0008, Revision 3 and 1-0019, Revision 1 which were submitted on 05/21/96 GNRO-96/00088 l

Gentlemen:

l l In regard to recent teleconferences with your staff and contractor personnel,  !

l Entergy is submitting additional information to supplement our May 21, 1996- I request for relief to portions of ASME Section XI. Additionally, this letter also corrects a typographical error in the Summary of Relief Request And Relief Request Revisions.

I l-0008 Rev. 3. Inservice inspection of CRD and incore Housina Welds & Flance l Boltina l

In refueling outages 4 and 5, GGNS has changed out 18 and 22 CRD drive mechanisms, respectively. Visual examinations for bolting associated with forty (40) CRD mechanisms have been performed (a total of 320 bolts). Twenty-eight mechanisms are scheduled to be changed out in our upcoming refueling outage.

Our current plans are to examine all removed bolting and replace with new bolting.

GGNS has not removed any CRD support structures. Therefore, no surface examinations of the stub-to-flange welds have been performed.

, 1-0019 Rev.1. Inservice Examination of Reactor Pressure Vessel Items i

The summary of requested relief indicated that revision 2 of I-0019 was being

, requested. However, this was a typographical error. The correct reds!cn should be revision 1.

The N9 nozzle welds which are discussed in Relief Request I-00019, Revision 1 join the penetration seal to the safe end. As reported in the Relief Request, current ultrasonic

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examination coverage equals approximately 44% of the required ASME Section XI Code volume using a 45* shear wave examination.

9608050248 960731  ; O l PDR ADOCK 05000416 O PDR

1996 July 31, /00088 GNRO-96 l Page 2 of 4 l

l The subject welds are less that 4 inch nominal pipe size and join the safe end (304 material) to the penetration seal (304L material). The N-9 penetration i assemblies contain jet pump sensing lines for monitoring jet pump performance. l The portion of the Code volume interrogated by the 45' shear wave is the safe l end side of the weld (304 material) and the portion not currently examined is the penetration seal side of the weld (304L material).

Although these welds are size exempt from the augmented requirements of Generic Letter 88-01, NRC Position On IGSCC In BWR Austenitic Stainless Steel Piping, GGNS conservatively classified these welds as Category D welds requiring l augmented ultrasonic examinations using techniques best suited for the detection of IGSCC. Since the initial evaluation and categorization, these welds have received stress improvement by the induction heating stress improvement (IHSI) process and have been subsequently reclassified as Category C. As part of the IHSI process, the welds received before-and-after ultrasonic examinations, and combined with other examinations have now been examined, to the extent described in the relief request, four times each during the first interval. Because of the small diameter, materials of construction, and the nozzle function, the most likely mechanism for service induced degradation is IGSCC of the 304 material, and although the total Code volume is not interrogated, the area most susceptible to IGSCC is examined. The examination technique utilizes the 45' shear wave which is the preferred technique for detection of IGSCC.

Recognizing that GGNS is conservative by including the subject welds into the classification of GL 88-01, has performed IHSI, has examined the area most susceptible to any known degradation mechanism four times during the interval, I and has not experienced any known IGSCC in the reactor coolant pressure boundary, the completed examinations are believed to be adequate for ensuring integrity of the N-9 nozzle welds. However, as GGNS prepares to advance into its i second interval, these welds along with all other items where relief has been obtained during the first interval will be evaluated to determine if improved coverage can be obtained. A review of available information indicates that the configuration of the N-9 nozzle welds may permit the use of a 60* angle beam to supplement the 45' for obtaining an additional 30% coverage of the Code volume.

This cannot be confirmed until the examinations are actually performed and beam plots developed.

As evidenced by Revision 2 to Relief Request 1-0006, Revision 6 to Relief Requect 1-00010, and the deletion of Relief Request 1-0011 where welds have been eliminated from requests for relief because newer technology has permitted a successful examination of the Code volume, GGNS is conscious of our responsibility to evaluate previously identified limitations with newer technology and improve coverage where appropriate. Because of this, relief for the upcoming interval wi!I not be requested until each examination is evaluated based on the technology, experience, and equipment available at the time of the examination.

July 31, 1996 GNRO-96/00088 Page 3 of 4 At that time, the use of a 60' angle beam will be included into the examination technique for the N-9 nozzles to the extent possible, and if relief is still required, the confirmed additional coverage will be provided to the NRC during that

. submittal. One of the subject welds is currently scheduled for examination dunng Period 1 and the other during Period 2 of the second interval. The second interval is anticipated to begin June 1,1997.

If you require additional information regarding this submittal, please contact Riley Ruffin at 601-437-2167.

Yours truly, W C.R ML, sa n

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CRH/RR I cc: r J. Tedrow Mr. R. B. McGehee Mr. N. S. Reynolds Mr. H. L. Thomas Mr. J. W. Yelverton cc: Mr. L. J. Callan Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 Mr. J. N. Donohew, Project Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 20555

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