ML20073D018

Forwards Sasr 91-26, Full Structural Weld Overlay Design for Peach Bottom Unit 2 RWCU Weld 12-I-1D, in Response to Generic Ltr 88-01.Requests NRC Approval of Design & Repair Package

ML20073D018
Person / Time
Site:	Peach Bottom
Issue date:	04/19/1991
From:	Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20073D020	List: ML20073D018 ML20073D022
References
GL-88-01, GL-88-1, NUDOCS 9104260121
Download: ML20073D018 (3)

Text

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PIIILADEl,PillA ELECTRIC COMPANY NUCLEAR GROUP llEADQUARTERS 955-65 CilESTERBROOK BLVD.

WAYNE, PA 19087 5691 (215) 640-6000 NUCLEAR ENo1NCERINO & $0RVICES DCPARTMENT April 19, 1991 Docket flo. 50-277 E0-278 License No. Ul;l 44 Dth-56 U.S. Nuclear Regulatory Commission Attn: Document Control Desh Washington, DC 20555

SUBJECT:

Peach Bottom Atomic Power Station, Units 2 and 3 Request for NRC Approval of Design and Repair Package in Accordance with Genet w Letter 88-01

REFERENCE:

(1) Letter from G. J. Beck (PEco) to USNRC, dated March 21, 1991 (2) Letter from W. R. Butler (11RC) to G. J. Beck (PECo), dated March 28, 1991 Dear Sir In accordance with the " Staff Position on Reporting Requirements" provided in the Generic Letter 88-01 ("NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping"), Philadelphia Electric Company (PECo) requested NRC approval of a design and repair package associated with the repair of a crack-like indication in the weld of the Reactor Water Cleanup (RWCU) system piping for Peach Bottom Atomic Power Station (i'BAPS) Unit 2 (Reference 1).

In your response to our letter (Reference 2), you granted permission for PBAPS Unit 2 to return to operation. Additionally, you stated that the " final design package in part should include as-built overlay thickness information and final shrinkage stress evaluations as appropriate."

In response to this request, attached are two repcrts which provide a finalized design and repair package (Attachment 1) and a closure package for the weld repaar (Attachment 2). The

as-built overlay thickness information is contained in Attachment 2.

l With regards to the final shrinkage stress nvaluations, an j

engineering evaluation has determined that the sum of the niaximum j

stresses due to the final weld shrinkage and the maximum existing l

9104260121 910419 l PDR ADOCK 05000277 [88/

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U.'d. Nucloer Rogulatory Commission April 19, 1991 Roquost for NRC Approval of Design and Repair Page 2 in-Accordance with GL 88-01 i

cnnlyzed stresses is 5950 psi, which remains well below Code allowed limit.

l Also requested was "information on any planned mitigation j or replacement of the RWCU piping susceptible to IGSCC."

Susceptible welds in the safety class portion of the RWCU system are currently being reviewed and evaluated for application of mitigation techniques. Specific plans for mitigation activities, pipe replacement, or continued examination per Generic Letter 88-01 for all susceptible RWCU piping will be formulated following re-examination of the repaired weld (12-I-ID) and examination of a cample of the susceptible welds located in the non-safety portion of RWCU system. These examinations are planned for the next refueling outage. Similar mitigation activities are being connidered for Unit 3.

In the Reference 1 letter, we stated that a final package containing all necessary information concerning completion of the I weld repair would be transmitted by April 5, 1991. Due to outage l reinted delays, the weld repair did not occur until April 7, 1991 i which resulted in delay of the final submittal, j If you have any questions, please do not hesitate to contact us.

Very truly our ,

L.J l G. J. ck, Manager

! Licensing Section Nuclear Engineering & Services cci T. T. Martin, Administrator, Region I, USNRC J. J. Lyash, USNRC Senior Resident Inspector, PB i

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