ML20024G406

Forwards Request for Addl Info Re Facility Suppression Pool Temp Transients

ML20024G406
Person / Time
Site:	Monticello
Issue date:	12/12/1977
From:	Desiree Davis Office of Nuclear Reactor Regulation
To:	Mayer L NORTHERN STATES POWER CO.
References
NUDOCS 9102120393
Download: ML20024G406 (4)

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Docket No. 50-263 DEC 121977 i

Northern States Power Company ATTN: Mr. L. O. Hayer, Manager Nuclear Support Services 414 Nicollet Hall - 8th Floor Minneapolis, Minnesota 55401 Gent 1cmen:

RE:

MONTICELLO HUCLEAR GENERATING PLANT -

SUPPRESSION POOL TEMPERATURE TRANSIENTS As part of our continuing review of the effects of elevated suppression pool temperatures on safety-relief valve (SRV) discharge loads, we have recently transmitted a request for additional information to General Electric (GE) regarding topical report NEDE 21078P, " Test Results Employed by GE for BWR Containment and Vertical Vent Loads."

Certain infomation which we require in order to cocplete our revim of this report is of a plant-specific nature. Since you have adonted this topical report as part of your docketed material, we i

j are transmitting to you the enclosed request for additional information.

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You are requested to provide the information identified in the enclosure as soon as practical. Your projected submittal date for your response should be provided within ten days of your receipt of this letter.

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Ine naterial contained in NEDE 21076P, the supplemental generic information requested fron GE, and the plant-specific infomation i

requested in this letter will serve as part of the b6ses for our review of SRV loads in the Mark 1 Centainnent Long-Tem Progren (LTP).

Since the referenced report has been classified as proprietary unoer our rules, and since we have detemined that the requests contained in Part D of the enclosure are proprietary, they are, therefore, being I

withheld fron public disclosure.

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We are aware that the Mark I Owners Group is developing a quencher-

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-type SRV discharge device as part of the LTP. Although the quencher j

devices are believed to be less sensitive to elevated pool temperatures, fY l

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9102120393 771212 PDR ADOCK 05000263 P

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Northern States Power Company -

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j it it our view that licensee responses to the enclosed request for additional informattoa should be provided for each facility regardless' i

of the type of discharge device that will be utilized upon completion

?l of the LTP.

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-Sincerely, 4

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Don K. Davis, Acting Chief Operating Reactors Branch f2 Division of Operating Reactors 1

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Enclosure:

DISTRIBUTION:

Request for Additional Information w/ enclosure Part A & B (Part A - Non-Proprietary)

Docket Files (Part B - Proprietary)

RPSnaider i

w/ enclosure Part A i.

cc w/ enclosure (Part A):

NRC PDR See next page Loeal PDR i

DEisenhut JGuibert WButler Attorney, OELD I&E~(3)

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RMDiggs JRBuchanan TBAbernathy j

ACRS (16)

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3-DEC 121977 Nortbesti

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cc w/ enclosure (Part A):

~,A Gerald Charnoff. Esquire The Environmental Conservation Library Shaw. Pittman, Potts and Minneapolis Public 1.ibrary Trowbridge 300 Nicollet Mall 1800 M Street. N. W.

Minneapolis. Minnesota 55401 Washington, D. C.

20036 Arther Rernvist. Esquire Vice Presiteat - Law Northern States Power Company 414 Nicollet Mall Minneapolis, Minnesota 55401 i'

Mr. L. R. E11ason Plant Manager Monticello Nuclear Generating Plant Northern States Power Company Monticello Minnesota 55362 s.

Russell J. Hatling. Chairman Minnesota Environmental Control Citizonr. Association (MECCA)

I Eneasy Task Force l

14fhelbourne Avenue. S. E.

Minneapo' sis. Minnesota 55414 Mr. Kenneth Drugan i

Environmental Planning Consultant Office of City Planner Grace Building 421 Wabasha Street St. Paul, Minnesota 55102 Sandra S. Gardebring Executive Director Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville Minnesota 55ii3 Mr. Steve Gadler 2120 CA-ter Avenue St. Paul, Minnesota 55108 l

j Anthony Z. Roisman Esquire l

Sheldon. Harmon & Roisman 102515th Street. N. W., 5th Floor l

Washington, D. C.

20005

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'V REQUEST FOR ADDITIONAL INFORMATION t

REGARDING SUPPRESSION

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POOL TEMPERATURE TRANSIENTS i

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.I Part-A: Non-Proprieta ry.

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1.

Provide figures which depict the reactor pressure, safety / relief V

- hgt valve (SRV) discharge mass flux, and suppression pool bulk j:_

temperature versus time for the following events which are baseo i

,j; on current Technical Specification limits:

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(a) Stuck-open SRV during power operation assuming reactor scram il

. at ten minutes after the suppression pool reaches a bulk pool temperature of 110 F and all RHR systems are operable.

(b) Same events as in (a) above with only one RHR train operable, f

-b,,3 (c) Stuck-open SRV during hot standby assuming an initial 120 F bulk pool temperature and only one RHR train operat,le.

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(d) Automatic Depressurization System ( ADS) activated following y

~%N a small line break assuming an initial 120 F bulk pool V

temperature and only one RHR train operable.

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(e) Primary system is isolated and depressurized at a rate of y"pI 100 F per hour with an. initial 120 F bulk pool temperature t,

27d only one RHR train operable, if K?-

2.

Briefly describe the suppression pool temperature monitoring system at your facility and the relative location of the 5

~h temperature sensors to the SRV discht c, points.

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