ML19282A763

Discovered That Exhaust Mufflers Seismic Support Plates Had Been Omitted from Diesel Generator.Corrective Actions Initiated & Will Be Completed Prior to Fuel Loading

ML19282A763
Person / Time
Site:	North Anna
Issue date:	03/02/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
061A, 61A, NUDOCS 7903060465
Download: ML19282A763 (2)

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• 1 N epCO VIRGINI A ELECTRIC AND POWER COMP ANY, RICHMOND, VIRGINI A 23261 March 2, 1979 Mr. -James P. O'Reilly. Director

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Serial No. 061A

-.0ffice Inspection & Enforcement PSESC/JMD:adw:mc.

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U. S. Nuclear Regulatory Comission

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- Aegion II -

Docket No. 50-339.

'101 Marietta Street, Suite'3100 Atlanta, Georgia 30303

Dear,

Mr. 0'Reilly:

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_Undertheprovisionsof10CFR50.55(e),NRCRegionIIwasnotifiedon

> ~ January 31. 1979 concerning the lack of seismic supports and missle pro-i tection for.the' Unit 2 diesel generator mufflers. Following a field in-

! spection of the exhaust mufflers our personnel determined the mufflers-seismic support plates-had been omitted..

Following an engineering evaluation in conjunction with the diesel gen-erator manufacturers muffler loading recommendations, it has been detemined

! that subjecting the mufflers to seismic or tornado wind loadings may over-stress the roof support attachments. In addition, should a failure of a muffler or the associated exhaust piping located on the roof, cause a block-i age of the exhaust gases, the diesels operation-could be adversely affected.

• Corrective actions for cach diesel have been initiated to modify the j current exhaust systems. Each exhaust line will be modified to provide a

parallel exhaust path, originating within the service building structure.

3 Each diesel's exhaust will be aligned to discharge from a seismically

, supported unauffled exhaust line in addition' to the existing muffled exhaust

! arrangement. . - A flexible self-detaching fabric connector will be incorp-

orated in the exposed portion of each muffled exhaust line, downstream of i each exhaust line service building penetration. The flexible connectors will prevent potentially damaging muffled exhaust line movements, introduced from external sources, from being transmitted back to the associated unauffled ex-

. haust line within the building structure. Operating the diesels in this ven-

! dor approved manner presents no operational or reliability problems. Existing

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roof structures will be modified to provide the necessary seismic and missle

! protection for the new unauffled exhaust piping. In order to reduce the low-

, , pitch operating drone of.the diesels during periodic operations, the unmuffled exhaust lines will be secured via manually operated high temperature valves. .

- . The modifications.to the' Unit 2 diesel exhaust lines will be completed

! prior to fuel load. Pending the receipt of the isolation vsives, the~ un-

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muffled branches will. be blanked off. Should delivery of the isolation valves l be delayed beyond fuel load, portions of.the exposed muffled exhaust pipes, downstream of-the building penetrations, will be removed providing temporary

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. unmuffled exhaust paths. Eliminating portions of the exhaust system, exposed

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to possible damage and/or occulsion, ensures the diesels availability for j service..

i 79030604(of g L- _ --- _

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. Mr. James P. O'Reilly, Director

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' This submitta1Lshall be considered'a final report under the provisions of 10CFR50.55(e).. Should you require further information, pleasa. contact this

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lPVytr1!, -

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[ Sam l g) C. Br)own, Jr.%#

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. Senior Vice President Poymr Station Engineering ~and C nstruction

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- cc: ffr. -John G. Davis. . Acting Director Office of Inspection & Enforcement Mr. Harold R. Denton, Director- '

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, Office of Nuclear Reactor. Regulation

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