ML20084S468
| ML20084S468 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 05/14/1984 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NMP2L-0053, NMP2L-53, NUDOCS 8405250089 | |
| Download: ML20084S468 (2) | |
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I NUMOHAWK Y NIAGARA NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST, SYRACUSE, N.Y.13202/ TELEPHONE (315) 474-1511 May 14, 1984 (NMP2L 0053),
Mr. R. W. Starostecki, Director U. S. Nuclear Regulatory Commission Region I Division of Project and Resident Programs 631 Park Avenue King of Prussia, PA 19406 Re:
Nine Mile Point Unit 2 Docket No. 50-410 '
Dear Mr. Starostecki:
Enclosed is a final report in accordance with 10CFR50.55(e) for the problem concerning the reactor building roof design.
This problem was reported via telecon to Mr. L. Norrholm of your staff on December 9,1983 and was followed by an interim report on January 9,1984.
Very truly yours, C&W
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C. V. Mangan, Vice President Nuclear Engineering & Licensing CVM/TL:rla Enclosure xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. R. Gramm, Resident Inspector
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8405250089 040514 PDR ADOCK 05000410
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f NIAGARA M0 HAWK POWER CORPORATION NINE MILE POINT - UNIT 2 i-DOCKET NO. 50-410 Final Report for a Problem Concerning Reactor Building Roof Design i
Description of the Problem The reactor building roof deck was designed, fabricated, and erected as a Quality Assurance Category III structure.
The reactor building integrity must be maintained during and following an accident and/or seismic event.
Analysis of Safety Implications j
During normal operating conditions and following an accident and/or seismic event, the reactor building integrity must be maintained to provide means for 2
a controlled elevated release to the atmosphere.
To accomplish this, the reactor building must be maintained at a negative pressure with respect to the outside atmosphere._ If the integrity-of the reactor building roof cannot be ensured in an accident and/or seismic event, there is a possibility that airborne radioactive materials would be released to tiie atmosphere through the roof area.
However, it has been determined that even if this problem were to have remained uncorrected, it would not have adversely affected the safe operation of the plant for the reasons discussed below.
The reactor building. roof deck design, material, fabrication, installation, and inspection attributes have been re-evaluated in. detail and the
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requirements for Quality Assurance Category I and Quality Assurance Category III would be the same in all these areas with the exception of the inspection frequency.
For Quality Assurance Category III installations, quality control inspections were required on a weekly basis while Qual.ity-Assurance. Category I applications require daily inspections.
In addition to the above, in accordance with PSAR Section 13.6.3.35, the secondary containment negative pressure test will be performed prior to startup'hich w
will provide confirmation of the air infiltration rate'into the real: tor l.
building.
Consequently, assurance. exists that the' integrity of the as-built reactor building roof deck would be maintained during and following an accident and/or seismic event.
l Corrective Action The reactor building roof deck classification has been upgraded to QA Category I.
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