ML19276H551

Ro:On 791112,during Seismic Supports Analysis,Safety Factors on 11 Seismic Supports Found Lower than Expected.Unit Was in Cold Shutdown.Caused by Design Error in Initial Stress Calculations.Hangers Will Be Modified

ML19276H551
Person / Time
Site:	Davis Besse
Issue date:	11/13/1979
From:	Murray T TOLEDO EDISON CO.
To:
References
NUDOCS 7911290404
Download: ML19276H551 (1)

Text

.

., Q,

, g' ,

f .

November 13, 1979

,_s.

1g .

.y -

/...

3,'g>.,

g /y /

TO: U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region III Artention: Tom Tambling

SUBJECT:

Reportable Occurrence per Technical Specification 6.9.1.8.1 b'hile performing an analysis on seismic supports per I.E.Bulletin 79-02, ITT Grinnell personnel identified a total of eleven seismic supports on which the safety factor was lower than expected. This was caused by design errors in the initial calculations of the stress in these hangers.

These design deficiencies were discovered while the unit was in cold shutdown during the present outage. All affected hangers will be modified prior to the unit startup.

Since the supports affect more than one part of a redundant system, this inci-dent is being reported in accordance with Technical Specification 6.9.1.8.1.

Luis Reyes, NRC on-site inspector, was notified of the reportability of the design deficiency at 1445 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.498225e-4 months <br /> on November 12, 1979.

D C-Terry D. Murray Station Superintendent w Davis-Besse Nuclear Power Station Toledo Edison Company TDM/SNB/ljk 1421 $28 dooQ

.s lll 5 num 44 ~