ML20094P463
| ML20094P463 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 04/01/1992 |
| From: | Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-88-01, GL-88-1, NUDOCS 9204080163 | |
| Download: ML20094P463 (2) | |
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i I'lllLADEl.I'lilA El ECTRIC COMi%NY NUCl.HAR GROUP llEADQUARTERS 955 65 CilESTERBROOK lilND.
WAYNE. PA 19087 5691 (215) 640 6(KK) i NUCLl%R ENGINLt. RING A $t kVICt3 Dt 1%IriMI.NT April 1,
1992 Docket. Nos. 50-278 Licenso Nos. DPR-56 O.S. Nuclear Regultt wy Commission Attn Document Cont.al Desk Washington, DC 20555
SUBJECT:
Peach Bot. tom Atomic Power Stat. ton, Unf t 3 Supplomontal Information Concerning t.ho Roquest for NRC Approval of Wold Overlay in Accordance with Generic Lett.or 88-01
REFERENCE:
(1)
Letter from G.
J.,
Bock (PECo) to USNRC, dated November 14, 1991 (2)
Lot. tor from G.
J. Bock (PECo) to USNRC, dated January 17, 1992 (3)
Tolocon Between PECo and USNRC Staif, dated January 30, 1992
Dear Sir:
This letter is in response to a January 30, 1992 tolocon (Reference 3) in which the Nuclear Regulatory Commission staff requested iurther clarification to the Reference 2 correspondence discussing the wold overlay repair of a crack-like.indicotton in the weld of the Reactor Water Cleanup (RWCU) system piping in Peach Bot. tom At.omic Power Station, Unit 3.
These clarifications are discussed below.
I The Referenco 2 letter provided a brief discussion of t.ho mock-up f or t.ho PBAPS, Unit 2 wold overlay.
The primary intent of the mockup was to qualify the weld proceduro and the wolders.
The mockup wan not intended to moesure the offects of residual weld strosuus in erresting crack growth and as such, there were no of forts made to measure t P rse stressus in the mockup.
l p i,c 9204000163 920401 hDR ADOCH 0300o27g
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I p
FDR 1
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l U.S. Nuclear Regulatory Commission April t,
1992 Roquest for NRC Approval of Design and Hopair Pago 2 j
In. Accordance w!t.h Generic Lotter 88-01 i
Additional clarification was requested by the NRC st.af f concerning the accept. ability of the water flow through the pipo during the wold overlay.
As stated in the Referenco 1-let. tor, 1
l t.he flow maint.aln9d through the pipe during the overlay procosa j
was measured to 've 125 gpm, which is the normal operating flow for an RWCU pump.
S.tnce t.hla flow was 5% below the recommanded flow, a review of the as loft. condition was performed by Gonoral Electric.
This review concluded that the reduced flow 4
war acceptablo in this case for the following ronsons:
Previous applicat.lons of wold overlays have demonst. rat.od that some rouldual compressivo stressos woro prosent. with 11ttle or no-flow.
The flow in t.his case was very near the recommonded flow, 1.0.
95%, and would produce essont.lally the same residual compressivo stressos as 100% flow.
_j General Elt,ctric confirmed that the int.ont of the recome mjod flow value in their specification was not. to provid an absolute minimum, but. an adoquate flow t.o produco realdual compressive stressos.
The wold overlay that was applied was designed as a full structural overlay.
As such, the added presenco of residuni compressivo stressos in the insido diamotor of the pipe would provido added conservatism t.o assure long term cont.inued integrity of the pipo, i
it is our conclusion that the overlay meets all requirement.s defined by the approved design calculation and that all offoct.s due to overlay have bern considorod.
_If you have any questions, please do not het.itato t.o contact us.
Very truly yours,
-, &.a r/
m G.
J. Beck, Manager Licensing-Soction Attachmont i
cc:
'i'. T.
Mart.in, Administrator, Region I, USNRC J. J.
Lyasu, USNRC Senior Resident inspector, PBAPS i
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