LR-N970709, Provides Notification of Change to Util Plan for Repairing Core Spray Nozzle Weld N5B.Description of Commitment Change Made by Util,Encl

Provides Notification of Change to Util Plan for Repairing Core Spray Nozzle Weld N5B.Description of Commitment Change Made by Util,Encl

ML20199A615
Person / Time
Site:	Hope Creek
Issue date:	11/12/1997
From:	Eric Simpson Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LR-N970709, TAC-M99755, NUDOCS 9711180034
Download: ML20199A615 (5)

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NOV 121997 LR-N970709 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 GHANGE TO REPAIR PLAN CORE SPRAY NOZZLE WELD THROUGH-WALL LEAKAGE HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NPF-57 DOCKET NO. 50-354 >

Gentlemen:

This letter provides notification regarding a change to the PSE&G plan for repairing Core Spray Nozzle Weld N5B. In Letter LR-N970667, dated October 9,1997, and Letter LR-N970686, dated October 15,1997, PSE&G submitted plans and procedures related to the repair of the subject weld. The PSE&G repair plan was subsequently approved by the NRC in a letter dated October 17,1997 (TAC Number M99755). This commitment change has been made in accordance with the Nuclear Energy Institute (NEI)

" Guidelines for Managing NRC Commitments" and PSE&G Procedure NC.NA-AP.ZZ-0030(Q), " Commitment Management." Details concerning the change are provided in the attachment to this letter.

Should you have any questions regarding this information, we will be pleased to discuss them with you.

Sincerely, Attachment

!f0 F I 9711100034 971112 PDR ADOCK 05000354 P PDR lilElilEll!lllllllillllililli

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NOV 121997 6

Document Control Desk LR N970709 C M.. H. Miller, Administrator - Region i .

U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. D. Jaffe, Licensing Project Manager - HC U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 14E21 Rockville, MD 20852 Mr. S. Morris (X24)

USNRC Resident inspector - HC Mr. K Tosch, Manager IV Bureau of Nuclear Engineering P. O. Box 415 Trenton, NJ 08625

NOV 121997' i Document Control Desk LR-N970709 CEM BC Senior Vice President - Nuclear Engineering (N19)

General Manager - Hope Creek Operations (H07)

Director - QA/NT/EP (X01)

Director - System Engineering (H16)

Director - Design Engineering (N23)

Director - Licensing / Regulation and Fuels (N21)

Director . Nuclear Business Support (N10)

General manager - NBU Maintenance (X10) -

Manager - Hope Creek Operations (H01)

Manager- Plant Maintenance - Maintenance Programs and Services (X07)

Manager - System Engineering - Hope Creek (H18) '

Program Manager.- NRB (N38)

Manager - Hope Creek Licensing (N21)

. Station Licensing Engineer - Hope Creek (N21)

T. Roberts (X14)

J. Keenan, Esq. (N21)

Records Management (N21)

Microfilm Copy Files Nos.1.2.1 (Hope Creek),5.85

. f. '

ATTACHMENT NOV 121997 HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NPF-57 DOCKET NO. 50-354 COMMITMENT CHANGE RELATED TO REPAIR PLAN The following descr;bes a commitment change made in accordance with the NEl guidelines related to the repair plan for Core Spray Nozzle Weld N58.

BfR GROUND The PSE&G repair plan submitted in LR-N970667, dated October 9,1997, and the Framatome Weld Procedure Supplement 55-PS0008-00 submitted in Letter LR-N970686, dated October 15,1997, included specifications for performing the weld overlay. A summary of the repair specifications and plan is as follows:

Preheat will be maintained for the first three layers or 1/8 inch temperbead deposit thickness, whichever is greater. The maximum preheat temperature specified was 300 F with a maximum interpass temperature of 400 F. The preheat will be established 30 minutes prior to welding and maintained until the start of the post-weld heat treatment (PWHT). This portion of the overlay will be subjected to postheat at 450 F to 550 F and held for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> minimum. After the PWHT is completed and the nozzle is flooded (ambient temperature achieved),

the balance of the weld overlay will be deposited with 60 F minimum temperature and amt,ient +50 F maximum interpass temperature, to 0.545 inche 5 minimum final thickness, including the temperbead layers. In accordance with Code Case N432, the repair area will be nondestructively examined after a holding period at ambient temperature for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

DEFINITIONS:

The " holding period"is the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period after the temperbead deposit and heat affected zone (HAZ) has been cooled to ambient temperature (Refer to Code Case N-432).

" Ambient temperature" in the Commercial Nuclear Industry has generally been defined as 50 F maximum above the component ambient temperature immediately prior to the application of preheat for a weld repair activity. This definition provides for a " practical" reduction in the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold prior to acceptance NDE being performed.

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i Atta:.hm:nt LR-N970709 l

. , Commitment Change Rel;ted t) R:p:Ir Pl:n

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NOV 121997 COMMITMENT CHANGE:

The change redefines the maximum interpass temperature during the holding period following post-weld heat treatment (PWHT) from ambient temperature

+50*F to embient temperature +100 F resulting in a working maximum interpass temperature of approximately 200*F. This change will allow for continued uninterrupted welding during the balance of the non-temperbead portion of the structural weld overlay while still allowing the area of concern (i.e., the SA-508, Class 2 nozzle material) to be held for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at ambient temperature prior to the acceptance non destructive examination (NDE) being performed.

TECHNICAL JUSTIFICATION:

At Hope Creek during the Core Spray Nozzle Repair, the component ambient temperature is expected to be approximately 100*F. The ASME Code use of the term " ambient"is somewhat arbitrary. The ambient temperature of components vary depending on plant conditions (i.e., decay heat, coolant flow and temperature, containment temperature, etc.). It is not uncommon to find primary component ambient temperatures just prior to temperbead application to be frcm 80 F to 150 F.

The purpose of the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold at " ambient" is to provide sufficient time for hydrogen (in the unlikely event that it is present) to migrate, by solid state diffusion, and to segregate at discontinuity regions of high tensile stress.

in the unlikely event that the temperbead welding procedure was not properly executed and untempered martensite remained in the HAZ, a temperature below 200 F would be sufficient to ensure that transformation to martensite would be completed and that the hardenability would have peaked. Therefore, there l would be no difference if the maximum interpass temperature was 150 F or 200 F. Furthermore, the tensile strength of the SA-508, Class 2 materialis l essentially the same at 200 F as it is at 150 F and, therefore, will make little difference in terms of residual stress.

l In addition, the nearly identical repair performed to a Core Spray nonle at Vermont Yankee also used a 200 F temperature for the maximum interpass temperature Juring the holding period in order to complete the balance of the weld overlap without idle periods of no welding.

Based on the above, all the technical aspects for the Code required 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> hold l prior to acceptance NDE have been considered and increasing the maximum l

interpass temperature from 150 F to 200 F for this period will have no detrimental effect on the structural integrity of the repair.

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