ML20069B668

Submits Addl Info Re 940111 Relief Request for RHRSW Piping Localized Wall Loss in Accordance W/Gl 90-05,in Response to NRC 940224 Telcon Request for Info on Impracticality & Burden Associated W/Immediate Code Repair/Replacement

ML20069B668
Person / Time
Site:	Quad Cities
Issue date:	05/23/1994
From:	Schrage J COMMONWEALTH EDISON CO.
To:	Russell W NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
GL-90-05, GL-90-5, NUDOCS 9405310045
Download: ML20069B668 (2)

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Commonwrith Edison 1400 Opus Plces

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( C 7 Downers Grove. Illinois 60515

. May 23,1994 l l

l Mr. William T. Russell, Director Office of Nuclear Reactor Regulation ,

U.S. Nuclear Regulatory Commission 1 Washington D.C. 20555 I

Attn.: Document Control Desk i 1

1

Subject:

Quad Cities Station Unit 1 Additional Information Pertaining to Relief Request for Residual Heat l Removal Service Water (RHRSW) Piping Localized Wall Loss (Pitting)

NRC Docket No. 50-254 i

References:

(1) J.L. Schrage to T.E. Murley letter dated January 11,1994.

(2) Teleconference between CECO (J. Schrage) and the NRC (C. 1 Patel and G. Hornseth) on February 24,1994.

Mr. Russell, I

in Reference (1), Commonwealth Edison (CECO) requested relief from IWB 3000 of I ASME Section XI (the Code) for three instances of localized wall loss (pitting) on the Unit  ;

1 RHRSW piping. The Reference (1) submittal also provided CECO's evaluation of the l localized RHRSW piping wall loss in accordance with Generic Letter (GL) 90-05, Guidance  !

for Performing Temporary Non-Code Repair of ASME Code Class 1,'2, and 3 Piping.  !

During the Reference (2) teleconference, the NRC requested additionalinformation with respect to the impracticality and burden associated with the implementation of an )

immediate code repair / replacement, as required by 10CFR50.55a(g)(4) and Section IWA i 4000 of the ASME Code, for the three instances of localized wall loss on the RHRSW  !

piping,.

The purpose of this letter is to describe the impracticality and burden associated with the implementation of an immediate code repair / replacement, and revise the Reference (1) letter to clarify those sections of the ASME Code from which CECO is requesting relief.

The impracticality for performing an immediate code repair for the three occurrences of wall thinning on RHRSW piping at Quad Cities Unit 1 is based upon the burden associated with an unnecessary extension of the Fall 1993 maintenance outage, given: the most practical type of repair (replacement of piping); the lead time for procurement of materials, engineering, and implementation of the replacement activities (approximately three weeks); the impracticality of performing a code repair after start-up from the maintenance outage; and the small amount of time until the start of the I thirteenth refuel outage (Q1R13) (start date of March 13,1994). y I

l O 9405310045 940523 PDR .ADOCK 05000254 P PDR

Mr. W.T. Russell May 23,1994 CECO has determined that the most effective repair for the localized wall loss is replacement of the affected piping. This option was chosen over weld repair based upon the number andproximity of pitting flaws, in addition to the small pipe size, which would limit the effectiveness of a weld repair. Given this repair method and the lead time for procurement of parts, implementation of an immediate code repair would have unnecessarily extended the Fall 1993 Unit 1 maintenance outage by approximately three weeks.

In order to implement an immediate code repair following startup from the maintenance outage in December 1993, CECO would have been required to immediatelv declare three of the four RHRSW trains inoperable, entering a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Limiting Condition of Operation (TS 3.5.B.5). Implementation of repairs to the piping for the three RHRSW pumps would have taken approximately 9 days to complete. Since this is greater than the Technical Specification-allowed 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> timeframe, CECO would have been required to shut-down Unit One. CECO believes that such a shut-down of the reactor would have been impractical and would represent unnecessary challenges to the reactor and associated safety systems.

Based upon: CECO's evaluation performed in accordance with GL 90-05 (as described in the Reference (1) letter); the impracticality and burden associated with the implementation of an immediate code-repair (as described above); and the small amount of time until the start of the thirteenth refuel outage (start date of March 13,1994), CECO requests relief from the requirements of 10CFR50.55a(g)(4) and IWA-4000 of ASME Section XI to perform an immediate code-repair of localized RHRSW piping wall loss (pitting). CECO has implemented a code replacement of the affected Unit 1 RHRSWpiping during the current refuel outage (01R13). This request revises the original relief request, which was transmitted in Reference (1).

If there are any further questions, please contact John L. Schrage at 708-663-7283.

Very truly yours,

• l i i ,

John L. Schrage Nuclear Licensing Administrator cc: J. Martin, Regional Adrninistrator - Regiva til C. Miller, Senior Resident inspector - Quad Cities Station C. Patel, Project Manager - NRR G. Hornseth, Technical Staff - NRR Office of Nuclear Facility Safety -IDNS