05000277/LER-1979-052, Forwards LER 79-052/01T-0

Forwards LER 79-052/01T-0

ML19260C159
Person / Time
Site:	Peach Bottom
Issue date:	12/11/1979
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19260C160	List: 05000277/LER-1979-052, Forwards LER 79-052/01T-0 05000277/LER-1979-052-01, /01T-0:on 791127,analysis Per IE Info Notice 79-28 Revealed Four Concrete Expansion Bolts in Concrete Block Walls W/Safety Factors of Less than Four.Caused by Deficient Design.Corrective Actions to Be Completed by 800101
References
IEIN-79-28, NUDOCS 7912180644
Download: ML19260C159 (2)

LER-1979-052, Forwards LER 79-052/01T-0

Event date:
Report date:
2771979052R00 - NRC Website

text

I' PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 1215) e 41 4000 December 11, 1979 Mr. Boyce H.

Grier, Director Office of Inspection and Enforcement Region I United States Nucle a r Regu la t ory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Grier:

SUBJECT:

Licensee Event Report Narrative Description The following occurrence was reported to Mr. Greenman, Region I,

Office of Inspection and Enforcement on November 28, 1979.

Reference:

Docket Number 50-277 50-278 Report No:

LER 2-79-52/1T Report Date:

December 11, 1979 Occurrence Date:

November 27, 1979 Facility:

Peach Bottom Atomic Power Station R.D.

1, Delta, PA 17314 Technical Specification Reference:

Technical Specification 6.9.a(9) requires reporting

" performance of structures, systems, or comporents that require remedial action or remedial action or corrective measures to prevent operation in a manner less conservative than assumed in the accident analysis in the safety analysis report Description of the Event:

Pursuant t o NRC Informatihn Notice No. 79-28, Engineering analyzed four concrete block walls located on Elevation 135' of the Units 2 and 3 Reactor Buildings.

These walls are the north and s outh walls of the North and South Isolation Valve Rooms, respectively, in both Reactor Buildings.

The architect engineer (A/E), Bech tel Corp oration has reanalyzed the seismic 1614 339 7 91218 0 6 + #r

Mr. Boyce H.

Grier Page 2

,3 D e c e mb e r 11, 1979 LER 2-79-52/lT capabilitics of the subject walls and has indicated that using present day calcula tional me th ods the safety factors of the concrete expansion bolts associated with the channels which support the subject walls are greater than 2,

but less than the desired safety factor of 4.

Consequences Of Event:

Engineering analysis indicated that the stresses in the outer fibers of the concrete block walls will not exceed code allowable values under the loading of the Design Basis Earthquake (DBE) and, therefore, the walls will not crack under a scismic event.

Cause of Event

The cause of this event is an engineering design deficiency.

Corrective Action

Redesign of.the support for the subject walls includes the installation of 18" channel to be bolted or veldei to existing channels or beams, respectively to raise the bolt safety f act ors to a minimum of 4.

Corrective action for the two Unit 3 valls is scheduled to be completed by December 15, 1979, while modifications to the corresp onding Unit 2 walls.i r e scheduled to be c omp le t e d by January 1,

1979.

Previous Similar Occurrences:

None.

Yours truly,

/,

feo pry o -

I. Cooney S td e ri n t e n d e'j

/

M.

nt Generation Division-Nuclear Attachment cc:

Director, NRC - Office of Inspection and Enforcement Mr. Norman M.

Haller, NRC - Office of Management &

Program Analysis 1614 340