ML19350A128

Forwards Response to Reactor Sys Branch Request for Info Re Operator Actions in Mitigating Consequences of Transient

ML19350A128
Person / Time
Site:	Summer
Issue date:	11/25/1980
From:	Nichols T SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8012020572
Download: ML19350A128 (2)

Text

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- g-t SOUTH CAROLINA Et.ECTRic a gas COMPANY

,oseerner.o.v..

CotuMe A, SoutM CAnottnA eseis 1

T. C. HicMots Jn.

, w. ....w o.ow taam ' November 25, 1980 -

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1 Mr. Harold R. Denton, Director

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Office of Nuclear Reactor Regulation ..

U. S. Nuclear Regulatory Commission Ci~

Washington, D. C. 20555 ,

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Reactor Systems Branch Questions,

Dear Mr. Denton:

As requested by Mrs. Amira Gill and Mr. C. Y. Liang, Soutn Carolina Electric and Gas Company, acting for itself and agent for South Carolina Public Service Authority, provides forty five (45) copies of marked FSAR pages giving information regarding' questions asked by the reactor systems branch. Due to the Safety Evaluation Report schedule, this information and other information on open items as it comes available is being transmitted by letter. This j material will be incorporated in the next FSAR amendment.

If you have any questions, please let us know.

Very truly yours, f t' WN T. C. Nichols, Jr.

RBC:TCN:pj

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V. C. Summer G. H. Fischer T. C. Nichols, Jr.

E. H. Crews, Jr.

O. S, Bradham O. W. Dixon, Jr.

, D. A. Nauman-R. B. Clary }00[

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W. A. Williams, Jr. 3 l

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Significant events in which a discussion of operator actions, in mitiga-f, r

ting the consequences of the transient is appropriate are main steam. . - ,

_ ,,line break, main feed line break, LOCA, and spurious acguation of the , p ECCS. The significance of operator action for events not mentioned I

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above is addressed in the response to question 211.59 which discusses M

the standard procedures followed to achieve a normal plant shutdown es following an event. The safety issues of concern during the time gj sequence of operator actions in general is addressed in both the FSAR 1'

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y and in the response to questions 211.59, 211.61, 211.108, and 211.115. , g A 5

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The limiting transient is the main steam line break. Operator action .mli 16 *

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d a s sesv./ * * + % e response.to questions 211.59 and 211.108. As stated in the response to , b7 question 211.108, the time at which operator action is required to limit ,

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the cooldown and primary repressurization following a steam line break y, b is in excess of 10 minutes. For the core integrity analysis following k either a main steam line break or depressurization of the main steam ))

. system, operator action is not reqcired at a specific time to obtain 7-or4 w

acceptable results. Desirable operator actions and the necessary *S 3 C. . g\

instrumentation' for indication are described for the steam break type a -

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d event in the response to Q 211.59. } .*.

% 1a In terms of establishing and maintaining long-term control of cooldown, 15

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j the feedwater line break is less limiting than the steam line break for '>

S1 the following reasons. During the early portion of the feedwater line o

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break, the break effluent consists of water or low quality steam which D ."

't carries less energy per pound than the dry, saturate-d steam assuraed in oj -

the steam line liceak analysis. Also, since the maximum break size for (l C' -

the feedwater line break is always smaller than for the steam line 3 ;

break, the steam discharge rate'must be smaller. Thus, the plant n 2 6-coo'.down is less rapid and of a smaller magnitude than for the steam 't i.

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