ML19317D697

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Responds to NRC 760811 Request W/Rept on Evaluation of Potential Reactor Vessel Overpressurization. Concludes That Design & Operating Procedures Adequate to Mitigate Consequences of Overpressurization Incidents
ML19317D697
Person / Time
Site: Oconee  Duke Energy icon.png
Issue date: 10/14/1976
From: Parker W
DUKE POWER CO.
To: Rusche B
Office of Nuclear Reactor Regulation
Shared Package
ML19317D698 List:
References
NUDOCS 7912060920
Download: ML19317D697 (1)


Text

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Mr. Benard C. Rusche, Director

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Operating Reactors Branch No. 1 J v; y 9 *

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,. a Re: Oconee Nuclear Station Dor %t Nos. 50-269, -270, -287

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Dear Sir:

Your letter dated August 11, 1976 informed us of a number of reported instances of reactor vessel overpressurization in Pressurized Water Reactor facilities in which the Technical Specifications implementing 10CFR50 Appendix G limi ations have been exceeded. It was requested that the Oconee Nuclear Station design and operating methods be examined to determine susceptability to overpressurization events.

The attached report is provided in response to your request. With the exception of a system hydro test, the Oconee reactort are not operated in a " solid water" condition. A steam space or gas space is always maintained in the pressurizer. The Oconee design also incorporates the use of a pilot actuated relief valve which has a dual setpoint to provide overpressure protection during startup and shutdown conditions. Additionally, the modest rate of system pressure increase from these highly unlikely initi-ating events and the alarm and indication features available will provide suf ficient time for operator action to terminate any event prior to reaching the Technical Specification limits associated with the 10CFR50 Appendix G requirements.

It is our conclusion that the design and operating procedures which currently exist are adequate to mitigate the consequences of postulated reactor vessel overpressurization incidents.

Ver truly yours, u.s w d . -

William O. Parker, .

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