ML19312C156

Forwards Evaluation of Post-LOCA Boric Acid Concentration Control Sys for Facility Reactors, in Response to NRC 760217 Ltr.Concludes That Flow Indication Unnecessary & Requests NRC Concurrence by 770101

ML19312C156
Person / Time
Site:	Oconee
Issue date:	08/06/1976
From:	Parker W DUKE POWER CO.
To:	Rusche B Office of Nuclear Reactor Regulation
Shared Package
ML19312C157	List: ML19312C156 ML19312C159
References
NUDOCS 7912060733
Download: ML19312C156 (2)

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DUKE power COMPANY Powen Bun.mwo 422 Socru Cnuncu Srazzr, Cnantorrz, N. C. 2824a WI L LI A M O. PA R M E R, J R.

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TE L E P=ic h t:AmtA 7C4 S rta= Peoovctiom 3 7 3-4c e 3 August 6, 1976 Q ,p}Y' N' 1 9 ,/,3, '.

Mr. B. C. Rusche f' >

Director of Nuclear Reactor Regulation -

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U. S. Nuclear Regulatory Comission (

• Washington, D. C. 20555 A wh g Attention: Mr. A. Schwencer k Re: Oconee Nuclear Station Docket Nos. 50-269, -270, -287

Dear Mr. Rusche:

In my letter of December 18, 1975 a description of a proposed method for assuring that sufficient core circulation exists to avoid boron concentration buildup that might adversely affect long-term cooling capability was presented. In your letter of February 17, 1976 it was stated that review of our proposal indicated that the boron concentration buildup would be limited to an acceptable value. It was further stated, however, that the reactor operator must be provided positive indication of flow through the affected lines. If this positive flow indication could not be provided prior to Oconee 1, Cycle 3 operation, your letter also stated that a preoperational test should be conducted to demonstrate sufficient flow through these lines under post-LOCA conditions.

In our response dated March 4, 1976 a commitment was made to test the boron dilution drain lines prior to resuming operation. This functional test has now been satisfactorily performed on both Oconee 1 and Oconee 2, verifying the design of the system. With regard to the future installation of flow indication equipment, it was stated that this matter is being pursued with the intention of installing an acceptable system prior to Cycle 4 operation. As the result of our continued study of this matter, the attached " Evaluation of the Post-LOCA Beric Acid Concentration Control System for Oconee Reactors" has been prepared.

This evaluation provides a description of the boron dilution system and an evaluation of the need for flow instrumentation and an assessment of the functional performance of the system. It is our conclusion that I flow indication is not necessary, and in fact, may not be prudent.

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,3 Mr. B. C. Rusche Page 2 August 6, 1976 The boron dilution system will be installed on Oconee 3 during the impending refueling outage. This system will be functionally tested in a manner similar to that performed on Oconee 1 and 2. We believe that your review of the attached report will confirm our conclusion that a positive flow indication system is not required. It is requested that you provide your concurrence with this approach by January 1, 1977 in order that planning for the Oconee 1, Cycle 4 refueling outage may be completed.

Ve truly yours, a d% gj , 6

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William O. Parker, Jr.

MST:vr Attachment

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