ML20127G443
| ML20127G443 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/23/1973 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 9211160601 | |
| Download: ML20127G443 (1) | |
Text
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Achte, 4 Mr. J F O' Leary, Director Directorate of Licensing
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D United States Atomic Energy Coanission s'
Y Wachington, p c 20545 rs
Dear Mr. O' Leary:
MONTICELLO NtiCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Improper Design of the Main Steam Chase Blowout Pancis Infonnation war received at the Monticello Nuclear Generating Plant ou May 3 confirming a design deficiency that we are reporting to your office in act.ordance with Section 6.7.B.2, Unusual Events, of the Technical Specifi-l cations, of the Provisional Operating License DPR-22.
i l
During the recent refueling outage, it was discovered that the rivet sizing calculations for the main steam blowout panels were based on l
blowout at 0.5 psid instead of 0.25 psid as described in the Monticello FSAR.
Based on a reanalysis, every other rivet was removed from the juncture of the wall frame and panel frame of each panel. As the panci design is based on rivet shear, utilization of half the number of rivets provideo for a design blowout at 0.25 psid.
l Yours very truly,
,',f L 0 Mayer, P.E.
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- t. r Director of Nuclear Support Services M
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MAY 291973 > 5 LOM/br RtWK RY
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MAIL SEC110N cc:
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Minnesota Pollution Control Agency CD s'
Attn. Ken Dzugan 3111 9211160601 730523 PDR ADOCK 05000263 S
.