ML19249B367
| ML19249B367 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 07/17/1979 |
| From: | Broehl D PORTLAND GENERAL ELECTRIC CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| NUDOCS 7909040335 | |
| Download: ML19249B367 (3) | |
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July 17, 1979 Trojan Nuclear Plant Docket 50-344 License NPF-1 M r. R. 11. Engelken, Director s
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Dear Sir:
IE Eulletin 79-14, dated July 2, 1979 expressed concern about the accuracy of input inforoation for seismic analyses of safety-related piping systens, and requested verification that analytical input data conforms to installed system configurations.
The verification program required by this bulletin is in progress.
We have a high degree of confidence that the progran will not identify any major problems which will affect the operability of safety-related piping systens at the Trojan Nuclear Plant, nor result in major codifi-cations to piping restraints and supports. This conclusion is based on the results of numerous reviews and re-evaluations involving field verification of piping systets, many of which have taken place in the last 12 months. A summary of these investigative efforts includes the following:
1.
Results of investigations initiated pursuant to other IE Bulletins have revealed no significant discrepancies.
Specifically, a.
Appropriate computer codes vere utilized for seistic analyses of safety-related piping (IE Bulletin 79-07);
b.
Appropriate weights were utilized in analyses for systens with Velan check valves (IE Bulle-tin 79-0'+); and Field inspection and testing of pipe support base c.
plates and anchor bolts did not identify any condi-tions affecting the operability of any Seiscic Cate-gory I piping system (IE Eulletin 79-02, Rev. 1).
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Pert!aryJ Geneel BecMc Corrperry M r. R. 11. Engelken July 17, 1979 Page two 2.
Re-evaluation and modification of supports for Seismic Category I piping in the Control-Auxiliary-Fuel Building Complex to accommodate revised SSE response spectra has not yet identified any conditions which affect the operability of saf ety-related systems (Control Bullding proceeding).
3.
A survey of safety-related piping was initiated in early 1978 to evaluate potential additional stresses due to grouted wall penetrations. This effort, which involved a walkdown of the piping and confirmation / closeout by drawirg update to show the location of wall penetrations on the piping isouetrics, did not identify any condi-tions which affected system operability (Licensee Event Report 78-20, reports dated July 21, 1978, October 6, 1978, and December 26, 1978).
4.
Design changes completed since initial plant operation have been controlled by an on going design change program.
Th is program includes the closecut of as-built drawings by walkdown and markup of design drawings, which are then incorporated on the originals.
Deviations from design, if any, are reviewed and resolved.
In this manner, a continu-ing "as-built
- status of design drawings is caintained.
5.
Prior to initial operation in 1975, the construction con-tractor provided details of the as-built configuration of all critical piping to the designer for confirmation against the stress design isometrics.
This review covered all Seismic Category I piping and other piping whose service condition necessitated stress analysis.
This review was conducted in parallel with a similar confirmation /walkdown of I;uclear Class I piping inside Contalument by an independent engineering company.
In addition to these checks, all the Seismic Category I piping system restraints were independently inspected by our Architect-Engineer's stress analysts to ensure that the as-built installation conformed to the design documents.
In each of the above reviews, the design isometrics were compared to the as-built installation to validate the design bases of stress analysis calculation.
All signi-ficant piping and piping restraint data was inspected and deviations from design were noted, evaluated, and resolved prior to initial operation.
Thus, considerable effort has been expended to ensure the accuracy of design documents, both prior to plant operation and during subsequent 3n.'n<.a u O e. s.i s k.
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Ped!crd Genercl E:e&.c Cctrpany
!!r. R. !!. Engelken July 16, 1979 Pa;;e three design changes and re evaluations of piping systems. We are confident that conditions identified during the inspections required by Eulle-tin 79-14 will not affect the operability of any safety-related syste:a.
If any di.screpancies are identified during the course of the verification prograi, thoy will be resolved in accordance with existing Technical Specifitatton requirenents.
Additional information concerning inspection schedules and design document listings will be provided in accordance with IE Bulletin 79-14.
Sincerely, g)'i /$,
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Director Of fice of luspection & Enforcement Director I;uclear Reactor Regulation ATItl A.
Schwencer Mr. Lynn Frank, Direc tor State of Oregon Departnent of Energy n ;. " 9 au es;
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