ML20006C290

Provides Addl Info Supporting Deferral of Seismic Qualification Util Group Walkdowns to 10R Outage.Performance of Walkdowns Provide Proper Scheduling & Priority for Resolution of USI A-46 for TMI-1

ML20006C290
Person / Time
Site:	Three Mile Island
Issue date:	01/26/1990
From:	Hukill H GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR C311-90-2009, GL-87-02, GL-87-2, NUDOCS 9002070287
Download: ML20006C290 (2)

Text

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I January 26, 1990 Z .

C311-90-2009 <

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10. S. Nuclear Regulatory Commission

. . JAttn: Document' Control Desk yf.g Washington; DC 20555- *

. ' Gentl emen:'

i, f Three Mile' Island Nuclear Generating Station, Unit 1 (TMI-1)

L' .  : Operating License No. DPR-50 Ls  : Docket No. 50-289

-Unresolved ~ Safety Issue:A-46 Resolution

(* .,

'NRCsletter dated December 4, 1989, regarding the TMI-1 Integrated Schedule  :

y Update, Lindicates that as- much of the- seismic verification walkdowns and t associated analyses required by Generic Letter 87-02 as possible should be

. performed prior to the 10R. outage. This-letter provides additional information

_ supporting deferral: of the SQUG walkdowns to the 10R . outage. >

OurEp1an is.not.to perform the walkdowns.and analyses on a-piecemeal basis. 3

The: e.ntire walkdown effort is scheduled.for a 2-3 week period during the 10R .

outag'e. Componc.nt work. packages will be, developed prior to the 10R: outage in preparation for the walkdowns. . The Seismic' Qualification. Utility Group (SQUG). '

. pilot ' studies indicate that the seismic verification 'walkdown and analysis- t

should be completed in one' effort, . utilizing the same.SQUG team' personnel and s

, ' technical experts to ensure consistency in approach and seismic evaluation.

. This.' consistency may be lost if the walkdown team personnel change. Additional ,

'SQUG training would be required for new personnel. Also,: performing walkdowns 3

t ' during. plant operations may present an undue risk to ' safe plant operation as-some. components:will1 require erection of scaffolding or-ladders in. order to-yfvisually.inspectcomponentsupportsandmountingdetails,andmostelectrical .

equipment would' require some disassembly to allow inspection of mounting

-details.

During'the initial development of the SQUG criteria and GpVN experience data

and training- efforts,- walkdowns and evaluations were performed in selected '

areas of the TMI-1 Control and Auxilia'ry Buildings by a prime SQUG contractor. .

The cable tray / conduit reviews were intended to benchmark the developing SQUG criteria. However it is important to note that no significant problems were ,

identified with respect to seismic qualification by use of experience data.

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GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation .

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-TMI-l'was seismically designed in accordance with the appropriate design basis criteria at' the time of initial plant licensing. Resolution of USI-A-46 is a l seismic verification effort to reassess the existing margins of safety and.to confirm that acceptable safety margins exist for equipment designed and l

-qualified'before. current criteria were developed. Therefore, we believe that l performance of the SQUG walkdowns during the 10R outage, as indicated in our November 3, 1989 letter, provides the proper scheduling and priority for '

resolution of USI A-46 for TMI-1 when compared to other projects on the Integrated Schedule for 9R, and we-intend to proceed on this schedule.

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Sincerely,

1. D. Hokill >

Vice President.and Director, TMI-1 DJD/311-89d cc: J. Stolz, USNRC R. Hernan, USNRC W. Russell, USNRCi, Region I F. Young, USNRC TMI-1 Site l

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