ML20236G002

Discusses Commitments Noted in Je Ward Re Meteorological Sys & Program Improvements Intended for Completion Prior to Restart.Util Wishes to Rescope Approach to Item 5 of Attachment B to

ML20236G002
Person / Time
Site:	Rancho Seco
Issue date:	10/29/1987
From:	Andognini G SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Miraglia F Office of Nuclear Reactor Regulation
References
GCA-87-733, NUDOCS 8711020371
Download: ML20236G002 (2)

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(l hdIlWILJIOl SACRAMENTO MUNICIPAL UTILITY DISTRICT O P, o, Box 15830, Sacramento CA 95852 1830,(916) 452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA OCT 2 91987 GCA 87-733 i

U. S. Nuclear Regulatory Commission l Attn: Frank J. Miraglia, Jr.

Associate Director of Projects Philips Building 7920' Norfolk Avenue Bethesda, MD 20014 Docket 50-312 Rancho Seco, Nuclear Generating Station Unit No. 1 License No. DRR-54 i Meterological System Program Improvements

Dear Mr. Miraglia:

On February 26, 1987, in letter JEW 87-228 from J. E. Ward (SMUD) to Mr. Frank Miraglia (NRC), the District identified numerous meterological system and program improvements intended for  ;

completion. prior t'o restart. A majority of these commitments are '

well on their way to' completion.  ;

However, item No. 5 of Attachment B to letter JEW 87-228, cannot be directly addressed based on our present knowledge of the divergence zone meterological flow phenomenon. This item indicates that SMUD will issue a purchase order for a Class "B" meteorology model. In order to evaluate which industry available models are most applicable to the unique meteorological flows at Rancho Seco, SMUD needs to identify the specific nature of theec flows from existing studies, and eventually from its own field study. Therefore, the District wishes to rescope its approach to item No. 5 of Attachment B. .-

The District's approach orior to restart'will be as follows: 1

1. Examine existing literature on the divergence zone meterological phenomenon to broadly assess tha uncertainty in the dose projection results of the existing Class A straight-line Gaussian model.

2. Modify the existing Emergency Plan and affected implementing procedures to modify Protective Action Recommendations to compensate for the identified uncertainties.

l 8711020371 871029 '

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RANCHO SECO NUCLEAR GENERATING STATION O 14440 Twin Cities Road, Herald, CA 95638-9799;(209) 333 2935 l

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' FRANK Jh MIRAGLIA, JR.

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GCA 87-733  !

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.The'Distriht" proposes.to accomplish the following activities aftersrestart:to further address the dose projection

uncertaintiesLintroduced'by the divergence zone phenomenon:-

'3. . Modify the1 existing class'A model to calculate dry deposition-using a conservative deposition' velocity;of O'.01 meter /second.

4.  : Perform..a field' study'during'a temporally' I representative portion of the divergence zone' period; (1.e.,-May to September 1988)~, utilizing. concurrent' p data obtained from several'.10-meter meteorological- l

towers located at strategic positions eastiof Rancho 1 Seco to'better define divergence zone flows.

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5. BasedLon the study results, enhance existing classLA y model by' developing site-specific adjustments to better. i 4 ' Laddress divergence zone flows.

6.; Modify the prior to restart' compensatory protective actions to be consistent with the enhanced Class A SModel-capability.

Prior to the commencement of'the' field study, the District wishes.

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>tol meet with cognizant NRC individuals to review the field study.

. protocol withJrespect to the optimum number and location.of the: 3

. study. towers.-  !

The, resolution of items'3<through 6,after restart.will not affect 1 the health and safety.of the_public because~the.necessary equipment to implement the Rancho Seco Emergency Plan'will be  !

4 operational'at restart. *

.Please-contact me if you'have any comments or questions. Members  ;

of yourJstaff,' with comments or questions requiring additional l

'informat' ion ~or clarification, may-' contact Mr. David Compton at extensionL4915.

Sincerely, s

l } l' 4 it& i i . Ca An nini

? ' Chief' Exec tive Officer, j

. Nuclear' lx 3 cc: G. Kalman,.NRC.Betheada (2) -;

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.A. D'Angelo,LNRC Rancho Seco  !

I. Spickler, NRC Bethesda ,

R. Fish, NRC, Region V, Walnut Creek J. Martin, NRC Region V, Walnut Creek 'l j

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