ML20091K673

Rev 2 to 940608 LAR to License DPR-22,re Section 3.7/4.7, SGTS

ML20091K673
Person / Time
Site:	Monticello
Issue date:	08/18/1995
From:	Hill W NORTHERN STATES POWER CO.
To:
Shared Package
ML20091K637	List: ML20091K634 ML20091K673 ML20091K682
References
NUDOCS 9508280115
Download: ML20091K673 (4)

Text

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l UNITED STATES NUCLEAR REGULATORY COMMISSION NORTHERN STATES POWER COMPANY MONTICELL NUCLEAR GENERATING PLANT DOCKET NO. 50-263 REQUEST FOR AMENDMENT TO OPERATING LICENSE DPR-22 REVISION 2 TO LICENSE AMENDMENT REQUEST DATED JUNE 8,1994 Northem States Power Company, a Minnesota corporation, requests authorization for changes to Appendix A of the Monticello Operating License as shown on the attachments labeled Exhibits B and C. Exhibit A contains a description of the means employed to correct secondary containment capability test data to calm wind conditions. Exhibit B contains the current Technical Specification Bases page 188 marked up with the proposed changes. Exhibit C contains revised Monticello Technical Specification Bases page 188 This letter contains no restricted or other defense information.

NORTHERN STATES POWER COMPANY l By l lltN William J tW Y/t Plant Manager Monticello Nuclear Generating Plant On this / day of 5 /998 before me a notary public in and for said County, personafly appeared, William J Hill, Plant Manager, Monticello Nuclear Generating Plant, and being first duly swom acknowledged that he is authorized to ,

execute this document on behalf of Northem States Power Company, that he knows the l contents thereof, and that to the best of his knowledge, information, and belief the statements i made in it are true and that it is not intorposed for delay.

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1 i~ j 3 <f EXHIBIT A  !

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^ Monticello Nuclear Generating Plant

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a Revision 2 to License Amendment Reauest Dated June 8.1994 -

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Additional Information Concoming License Amendment Request Dated June 8,1994,~

- Standby Gas Treatment and Secondary Containment Technical Ssecincetions  ;

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j The method to be used for correcting the test data to calm wind conditions is to plot wind j i  ; speed and secondary containment differential pressure data, recorded during the secondary j

icontainment capability test, on a graph with a copy of the " northerly" curve from Figure 5.1, j J Monticello Nuclear Generating Plant Reactor Building Pressure as a Function of Wmd Speed  !

o ' for Constant SBGTS Flow Rate, from the technical report " Summary Technical Report to the i I United States Atomic Energy Commission, Directorate of Licensing, on Secondary  ;

Containment Leak Rate Test" provided to the USAEC by letter dated July 23,1973. .

j l Reference to this technical report is proposed to be included in the bases section for Standby -  !

! Gas Treatment and Secondary Containment Technical Specifications via our April 20,1995 l letter transmitting Revision 1 to our License Amendment Request Dated June 8,1994. If the

test data plots below the curve, then the test has successfully demonstrated that the

secondary containment system has sufficient capability to satisfy the license requirement of i maintaining at least a % inch of water vacuum under calm wind (u < 5 mph) conditions. If the )

test data is at least % inch of water vacuum but plots above the "northerty" curve, then the test

! conditions and data would be evaluated for possible application of the " southerly" curve of Figure 5.1.

! The use of the " northerly" curve provides the most limiting and conservative curve for extrapolating secondary containment capability test deta to calm wind conditions. The i Monticello Reactor Building, providing the secondary containment structure, is constructed i'

such that the south face of the building has a large penetration consisting of the Reactor i Building Rail Car Door opening and the two reactor building ventilation supply fan openings.

The west face of the building has two reactor building ventilation supply fan openings. The

north and east faces have no such openings. Thus the south face has the greatest area of  :

l penetration openings. Thus " northerly" winds data used to establish the correlation l

: represented by the " northerly" winds curve represents the worst case effect of providing an .  !

[ assist to the Standby Gas Treatment System in maintaining a Secondary Containment vacuum. This vacuum assist is due to the building wake effect creating a low pressure area on l

!~ the south face of the building' acting on the very large secondary containment penetration area

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' on the south face. Comparison r* the secondary Containment capability test data to the~.

curves provided in the technical report " Summary Technical Report to the United States Atomic j[. Energy. Commission,~ Directorate of Licensing, on Secondary Containment Leak Rate Test" .!

provided to the USAEC by letter dated July 23,1973, ensures that the Standby Gas Treatment l

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f - Systeni has the capability to establish a sufficiently greater vacuum in the secondary with the

,non-calm wind conditions, such that under calm wind conditions the requirements of the plant

-Technical Specifications and the assumptions of the plant Pad 100 dose analysis are satisfied.

4 1 During the Secondary Containment Capability Test, the following meteorology information is

' recorded: Wind Speed, Wind Direction, Air Temperature. This information is normally gathered from a periodic printout of the primary meteorology tower instruments. The printout is  !

updated every 15 minutes with 15 minute average data. The wind speed and wind direction is l

- measured at the 43 meter position of the plant's primary meteorology tower. This is the most '

representative height for conditions impinging at the top of the Reactor Building. Data is i

normally available from either of two channels for each instrument on the meteorology tower. ,

if data is not available from either 43 meter instrument, then the 100 meter and 10 meter .

) instrument would be used if data is not available from any of the primary meteorology tower l

instruments, then data could be acquired from the plant's backup meteorology tower. If both

- the primary and backup towers are not available, then data could be obtained from the Reactor l

Building analog wind speed and direction recorders. The primary and backup towers provide digital data from the analog wind speed and wind direction sensors by sampling the sensors every 5 seconds and averaging the data for 15 minutes. Updated data is printed in hard copy

and copied to a computer data file every 15 minutes. If the printer is not available, the data

may be accessed from the computer files. Additionally, the data file records minimum and i

maximum 5 second reading during each 15 minute averaging period which may be used for a evaluation of unusually unstable conditions. The meteorology monitoring system meets the

intent of Proposed Revision 1 to Reg. Guide 1.23, Meteorological Programs in Suppod of l l Nuclear Power Plants. )

. Operating experience has demonstrated that the Reactor Building responds relatively slow with. l respect to changes in differential pressure due to changes in wind velocity or direction. The 15 l

minute average data as displayed is adequate to provide assurance that the correction method  ;

i used for non-calm wind conditions will show that Secondary Containment capability is adequate.

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l Exhibit B

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Monticello Nuclear Generating Plant Revision 2 to License Amendment Recuest Dated June 8.1994 Proposed Changes Marked Up on Existing Technical Specification Pages Exhibit B consists of the existing Technical Specification pages with the proposed changes marked up on those pages. Existing pages affected by this change are listed below:

Eana 188 Insert text for page 188 B-1