05000344/LER-1983-001, Forwards LER 83-001/01T-0.Detailed Event Analysis Encl

Forwards LER 83-001/01T-0.Detailed Event Analysis Encl

ML20028F500
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	01/20/1983
From:	Broehl D PORTLAND GENERAL ELECTRIC CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20028F501	List: 05000344/LER-1983-001, Forwards LER 83-001/01T-0.Detailed Event Analysis Encl 05000344/LER-1983-001-01, /01T-0:on 830106,field Insps & Review of Const Records Revealed as-built Conditions of knock-out Panel & wall-to-roof Connection Different than Those Considered in Previous Analyses for Three Masonry Walls.Mods Underway
References
TAC-12369, NUDOCS 8302010398
Download: ML20028F500 (4)

LER-1983-001, Forwards LER 83-001/01T-0.Detailed Event Analysis Encl

Event date:
Report date:
3441983001R00 - NRC Website

text

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Donald J. Broehi Assistant Vce President January 20, 1983 Trojan Nuclear Plant Docket 50-344 License NPF-1 Mr. R. H. Engelken, Regional Administrator U. S. Nuclear Regulatory Commission Region V Creekside Oaks Office Park 1450 Maria Lane, Suite 210 Walnut Creek CA 94596-5368

Dear Sir:

Trojan LER 83-01 Masonry Wall Nonconformances In accordance with the Trojan Plant Operating License, Appendix A, Technical Specification 6.9.1.8.1, Licensee Event Report No. 83-01, describing two separate as-built conditions which are not in conformance with boundary conditions previously considered in structural analyses for in plane and out-of plane masonry wall seismic response, is attached.

This is a 14-day follow-up report for an immediate reportable occurrence which was reported to Mr. M. H. Malmros, U. S. NRC Site Inspector, on January 6, 1983.

Sincerely, Attachment c:

Mr. Robert A. Clark, Chief Operating Reactors Branch No. 3 Division of Licensing U. S. Nuclear Regulatory Commission Mr. Lynn Frank, Director State of Oregon Department of Energy 8302010398 830120 PDR ADOCK 05000344 S

PDR 121 s W simon street. rtcand. Gregon 97204 4

I Trojan Nuclear Plent January 20, 1983 i

Docket 50-344 LER 83-01 License NPF-1 Page 1 of 3 Reportable Occurrence 1.

Report No:

83-01 2.

Report Date:

January 20, 1983 3.

Occurrence Date: January 6,1983 l

4.

Facility:

Trojan Nuclear Plant, PO Box 439, Rainier OR 97048 5.

Identification of Occurrence:

Two separate as-built conditions, were determined to exist which are not in conformance with design drawings utilized to determine boundary conditions previously considered in structural analyses for in plane and out-of plane masonry wall seismic response. The nonconformances affect the following walls between the top floor (at Elevation 93 f t) and building roof (at approximately Elevation 117 f t):

l a.

Control Building north wall (Column Line 41) j b.

Approximately 31 feet of the Control Building east wall (Column Line N) c.

Approximately 68 feet of the Auxiliary Building north-wall (Column Line 46)

The first condition consists of a design change made during construc-tion wherein the addition of a 1/4-in. steel plate form, near the top of the wall, results in interruption of wall vertical reinforcing bars, which were intended to overlap those from the concrete roof slab.

A :*ud was, however, welded to the steel plate providing partial development of the wall reinforcing steel at this interface. Poured concrete, formed by the steel plate, replaced the upper courses -

of masonry unie.s.

The second condition is the existence of a horizontal bond breaker (paper joint) built into the control room north wall to create a 16-foot-high by 45-foot-wide knockout panel.

2 l

6 Conditions Prior to Occurrence:

t The Plant was in Mode 1 at 100 percent power when the nonconformance conditions were determined to exist.

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7.

Description of Occurrence:

Pursuant to a request from the NRC Structural Engineering Branch, related to LER 79-15, all of the Trojan safety-related masonry walls were reevaluated for compliance with SRP 3.8.4, Appendix A criteria.

i

4 Trojan Nuclear Plant' Jcnuary 20, 1983 Docket 50-344 LER 83-01 License NPF-1 Page 2 of 3 During the review of design documentation, structural steel vendor drawings, construction subcontractor reinforcing steel layout drawings 4

and cut sheets, and available construction photographs to verify as-built conditions, information not before known to exist was dis-covered. Together with interpretations of construction photographs and additional engineering inspection data, the nonconformances were discovered. A more detailed description of the nonconformances is provided in Attachment 1.

t 8.

Designation of Apparent Cause:

1 The design change at the wall-to-roof interface was documented and initially reviewed by Bechtel engineers during construction, but was not incorporated into civil or architectural as-built drawings. The capacities calculated for these walls, and relied upon in analyses pursuant to LER 78-13 and 79-15, assumed the originally intended, more substantial connections shown on the civil and architectural drawings.

)

Although vertical paper joints bordering the knockout panel in the north wall of the control room are shown on architectural drawings, no l

horizontal joint is shown on the drawings. Previous evaluations of wall behavior assumed this wall to be continuous between Elevation 93 f t and Elevation 117 f t.

9.

Significance of Occurrence:

These nonformances have no effect on the health and safety of the public. New analyses accounting for the known conditions of these walls have shown that the walls will adequately resist the loads, both in plane and out-of plane, resulting from the Safe Shutdown Earthquake.

Hocever, it has been concluded that not all structural elements af-fected continue to provide the capacity to withstand the Operating i

Basis Earthquake (OBE) loads factored by 1.4.

A detailed discussion of the effect of the nonconformances is provided in Attachmen. 2.

10.

Corrective Action

Reviews have been completed of available design and construction i

documentation, including field change request logs, contractor and aabcontractor drawings and data, and construction photographs to 2

provide assurance that the subject nonconformances do not exist else-where in the Plant.

Modifications vill be made to upgrade existing in plane transfer mechanisms and in plane shear capacities in accordance with criteria provided in FSAR Sections 3.7 and 3.8, and PGE-1020, " Report on Design Modifications for the Trojan Control Building", and relatad documents.

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Trojen Nuclsar Plsnt Jcnu ry 20, 1983 Docket 50-344 LER 83-01 License NPF-1 Page 3 of 3 Modifications will be made to upgrade existing out-of-plane shear transfer mechanisms and wall out-of plane capacities in accordance with LER 79-15 criteria, and also to provide unfactored OBE capacitie.4 in accordance with current NRC Standard Review Plan, Section 3.8.4, Appendix A criteria.

The modifications will be performed by core drilling downward through the Control Building and Atxiliary Building roof slabs into the walls, installing new reinforcing steel bars, and grouting the annular space with high strength non-shrink grout. A representative sketch of the planned modifications is shown in Attachment 3.

These modifications are being expedited and are currently scheduled for January-March 1983.

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