ML19351F864

Forwards Errata to Vol 2 & Full Vol 4 of Analysis of Hydrogen Control Measures at McGuire Nuclear Station. Sys for Controlling Effect of Excessive Hydrogen Generation Has Been Installed

ML19351F864
Person / Time
Site:	Mcguire, McGuire
Issue date:	02/17/1981
From:	Parker W DUKE POWER CO.
To:	Harold Denton, Youngblood B Office of Nuclear Reactor Regulation
Shared Package
ML19351F865	List: ML19351F864 ML19351F869 ML19351F872
References
NUDOCS 8102200394
Download: ML19351F864 (2)

Text

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.' DUKE POWER COMPANY i

Powen Britoiso 422 Ncin Curucu Sinter. C LARLoTTE.1 C. 28242

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] g '} [7 7} } } 373-4393 Mr. Harold R. Denton, Director ' ' .H S Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 i Attention: Mr. B. L Youngblood I Licensing Projects Branch No. 1 i

Re: McGuire Nuclear Station Docket Nos. 50-369 and 50-370

}

Dear Mr. Denton:

The accident which occurred at TMI Unit 2 resulted in the generation of hydrogen beyond the limits specified in 10CFR 550.44. This excessive hydrogen generation was primarily due to premature termination of the emergency core cooling system (ECCS). Duke Power Company belit,:es that measures taken subsequent to the accident at TMI Unit 2 effect uely

, preclude premature termination of the ECCS in the event of an ncident l requiring its initiation. Therefore, hydrogen will not be gercrated in 1

amounts in excess of the limits set forth in 10CFR 550.44 and ne addi-

tional safety systems are necessary.

However, Duke has installed a system for controlling the effects of excessive hydrogen generation in the extremely unlikely event of an

[ accident resulting in such hydrogen generation at IIcGuire Nuclear

Station. This system is described in the document " Duke Power Company, An Analysis of Hydrogen Control Measures at McGuire Nuclear Station."

Volumes 1 and 2 of this document were submittet. to the NRC on November 17, 1980. Volume 3 was submitted to che NRC on January 5, 1981. Fifteen _ copies of Volume 4 are enclosed with this letter. Also enclosed are fifteen copies of errata for Volume 2. This document is i summarized below, i

Chapter 1 provides an introduction to the control of hydrogen generation at light water cooled nuclear power plants.

. Chapter 2 presents analyses which have been performed to study hydrogen burn transients in ice condenser containments for an accident sequence similar to the TMI-2 accident. At 'IMI-2 equipment failure coupled with j dynamic man-machine interactions led to an arrested core melt event, s 1 o 210034r f

- Mr. Harold R. Denton, Director February 17, 1981 Page Two Accident sequences proceeding beyond the stage of an arrested core melt include events beyond the question of hydrogen generation and as such are not appropriate for evaluating the effectiveness of a hydrogen control system. Therefore, in order to eve aate the effectiveness of a hydrogen control system it is rearonable te select an accident sequence that is comparable to the TMI-2 net _'_..c. As such, the small break LOCA with failure of safety injection ( the S 2D sequence in WASH 1400) was selected for this eva.1 :ation. The selection of a small break LOCA is even more approprie.te cu- idering the conclusion of WASH 1400 that "(these) sequences contribute the largest probability to PWR core melt." The S2 D sequence is representative of TMI-type sequences in which a hydrogen control system may be called upon to function.

Chapter 3 provides a description of the Erergency Hydrogen Mitigation (EEM) system which has been installed at McGuire Nuclear Station Unit 1. The operation and testing of this system is described in Chapter 8. A test program which demonstrates the effectiveness of the EHM system igniters is described in Chapter 5.

Chapter 4 describes a detailed structural analysis of the McGuire containment which established the functional capability of the McGuire containment as 67.5 psig. The structural response of the McGuire containment to a postulated localized hydrogen detonation is discussed in Chapter 7. This evaluation was conducted even though investigations show detonable mixtures of hydrogen will not be formed as the result of a postulated TMI-type accident at McGuire. The analyses discussed in Chapters 4 and 7 provide assurance that the McGuire con-tainment can withstand the effects of a TMI-type accident.

Chapter 6 discusses the effects of hydrogen combustion on equipment located inside containment.

Very truly yours,' ~

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W.

.. d ~ - tl . l '

William O. Parker, Jr; TEH:scs

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