ML20212D560
| ML20212D560 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/27/1986 |
| From: | Tiernan J BALTIMORE GAS & ELECTRIC CO. |
| To: | Ebneter S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-11, NUDOCS 8701020077 | |
| Download: ML20212D560 (2) | |
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BALTIMORE C -. -O/-
GAS AND ELECTRIC CHARLES CENTER P. O. BOX 1475 BALTIMORE, MARYLAND 21203 4
- JOSEPH A.TIERNAN Vict PntstDENT
- NucLEAn ENEnGY j -
3 March 27,1986 l
Mr. Stewart D. Ebneter, Director Division of Reactor Safety Region I United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 r
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2, Docket Nos. 50-317 and 50-318 I&E Bulletin 80-11, Masonry Walt Design
REFERENCES:
(a) - NRC letter from S. D. Ebneter to A. E. Lundvall, Jr. (BG&E),
r Combined Inspection Report Nos. 50-317/86-01 and 50-318/86-01, dated February 18,1986
.(b) ~ BG&E letter from M. 3. Gahan, III to A. A. Varela (NRC), I&E Bulletin 80-11, Masonry Walls, dated January 24,1986 (c) BG&E letter from A. E. Lundvall, Jr. to E. 3. Butcher (NRC), same subject, dated June 12,1985 Gentlemen:
Reference (a) provided the findings of your inspection conducted on January 13-17, 1986, regarding 1&E Bulletin 80-11, Masonry Wall Design. During the inspection you noted a discrepancy between the actual boundary conditions found in the plant and those assumed in our reanalysis for walls "T", "U" and "W" at Elevation 45'-0".
Specifically, no steel dowels or other connections could be found between wall "T" and the ceiling beam, in Reference (b), we committed to evaluate the impact of this discrepancy and notify you of our results and any necessary plans for corrective action.
Accordingly, we have performed an analysis of these walls assuming no connection between the walls and ceiling. Walls "T" and "W" were analyzed using a finite element model to account for plate action and were assumed to displace freely along the top.
The stiffness provided by the stair landings at Elevations 51'-4", 57'-0" and 63'-4" was incorporated into the model. An analysis was not deemed necessary for wall "U", since the boundary and support conditions for this wall are enveloped by wall"W". The results of our analysis confirm that the stability of walls "T", "U" and "W" is not compromised as a result of the missing dowels, since the stresses obtained are within the allowables used in the original reanalysis. It should be noted that design conservatisms, such as that associated with the determination of the seismic input motion (see Reference (c)),
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. MriSJ D, Ebneter ' March 27,1985 I) y' 0I
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l remain in the analysis. Since. the allowable stresses are not exceeded, and because
's additional design margin exists for these walls, we conclude that the walls meet their functional criteria.'
s fif you should have any questions, please do not hesitate to contact. us.
Very truly rs, M
JAT/M3G/BSM/dmk cc:
D. A. Brune, Esquire
- 3. E. Silberg, Esquire Mr. D. H. Jaffe, NRC
-- Mr. T. Foley, NRC A. A. Yarela, NRC l'
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