ML20127G841

Forwards Page 161 of Proposed TS Re Suppression Pool Water Temp Limits Forwarded W/Stated 750715 Notice

ML20127G841
Person / Time
Site:	Monticello
Issue date:	08/01/1975
From:	Ziemann D Office of Nuclear Reactor Regulation
To:	Mayer L NORTHERN STATES POWER CO.
References
NUDOCS 9211170437
Download: ML20127G841 (3)

Text

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Docket No. 50-263 Cliebron OI6E (3)

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y g p39 A*ITN: Mr. L. O. Mayer Director of Nuclear Support JSaltzman TBAbernathy RMDiggs Services BCBuckley 414 Nicollet !!all DLZiemann Minneapolis, Minnesota 55401 SKari OMiller Gentlemen:

ily our letter dated July 15, 1975, we forwarded you a copy of our Hotice of Proposed Issuance of an Amendment to Facility License No. .'PR-22 relating to suppression pool water temperature limits for the Monticello Nuclear Generating Plant. Some copies of the proposed Technien! Cpecifi-cations did not include page 161. Enclosed is a copy of page 161, in case it was omitted from your copy.

Sincerely, sstod MW

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twants1."Dem"" pn Dennis L. Ziemann, Chief Operating Reactors Branch J2 Division of Reactor Licensing

Enclosure:

Proposed Tech Spec Page 161

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Arthur Renquist, Esquire The Environmental Conservation Vice President - Law Library Northern States Power Company Minneapolis Public Library 414 Nicollet Mall 300 Nicollet Mall Minneapolis, !!innesota 55401 Minneapolis, Minnesota 55401 Gerald Charnoff Mr. D. S. Douglas, Auditor Shaw, Pittm:in, Potts 6 h'right County Board of Commissioners Trowbridge Buffalo ~, !!innesota 55313 910 - 17th Street,.N. W.

Washington, D. C. 20006 h'arren R. Lawson, M. D.

. Secretary and Executive Officer floward J. Vogel, Esquire State Departncnt of llealth Legal Counsel University Canpus 2750 Dean Par):way .

Minneapolis, Minnesota 55440 Minneapolis, Minnesota 55416

. _ Mr. Gary Williams Steve Gadler Federal Activities Dranch 2120 Carter Avenue Environmental Protection Agency St. Paul, Minnesota 55108 230 South Dearborn Street Chicago, Illinois 00604 lir. Daniel 1. richer Assistant City Attorney -

638 City Ib11

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St. Paul, Minnesota 55102

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Mr. Kenneth D:utan ~

Enviror,aental Planning -

Consultant _.

St. Paul City Planning 421 Wabasha Strcot St. Paul, Minnesota 55102 Sandra S. Gardebring Special Assistant Attorney General Counsel for Minnesota Pollution .

Control Agency 1935 h'. County Road B2 Roseville, 'linnesota 55113 Anthony 2. Roisman,-Esquire .

Derlin, lloisman and Kessler 1712 N Street, N. W. .

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Washington, D. C. 20036 Og

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Bases:

4.7 A. Primary Containment The water in the suppression chuber is used only for cooling in the event of an accident; i.e., it is not used for normal operation; therefore, a weekly check of the temperature and t volume is adequate to assure that adequate heat removal capability is present. For additional t

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margin, these will be checked once per day. ,

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' The interiorn of the drywell and cuppressicn chamber are painted to prevent runting. The inspec- ,

tion of the paint during each major refueling outage, approxinately once per year, accures the paint is intact und is not deteriorating . Experience with this type of paint indicates that the inspection interval is adequate.

Because of the large volume and thermal capacity of the suppression pool, the volume and temperature normally changes very slowly and monitoring these parameters daily is sufficient to e.;tablish any temperature trends. By requiring the suppression pool temperature to be continually monitored and frequently logged during periods of significant heat addition, the temperature trends will be closelv followed so that appropriate action ca:1 be taten. The requirement for an external visual examination -

following any event where potentially high loadings could occur provides assurance that no significant damage was encountered. particular attention should be focused on structural discontinuities in the vicinity of the relief valve discharge since these are expected to be the points of highest stress.

Visual inspection of the suppression chamber including water line regions each refueling outage is adequate to detect any changes in the suppression charher structures.

The primary containment preoperational test pressuren are btned upon the ed culated primary containment preccure respense in the ecent of a lons of coolant accident. The peak drywell prhssure would be about 41 psig, t.hich vauld rapidly reluce to 25 paig within 10 seconds follow-

'ing the pipe break. Followire, the pipe break, the cupirension ch sber prencore risen to 25 psig within 10 seconds, eqtgalizes uith drywell prernure and therrafter rapidly decay with the dry-well pressure decay. See Section 5.2 5 ICAR. .

The design preccure of the dryvell and ubcarption chuber ir 56 paig. See Section 5.2.5 FSAR.

The design Icak rate is 0 5%/ day at a prencure of 56 pr:a. As indicated above, the preccure resp'onse of the drywell and suppreccion chatber following an accident. woul<l be the came after-about 10 seconds. Based .on the calculated containment I recnure renponce di;; cussed rdme, the primary containment preoperational tect presnures were cho:ca. Alno,1/2:el on the I,riwary -

containment pressure response and the fact that the drywell and cuppressicn chamber function

., as a unit, the primary containment will be tested an a unit rather than the individual compo-pents separately. ,

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