ML20051P392
| ML20051P392 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/11/1982 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8205170385 | |
| Download: ML20051P392 (2) | |
Text
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TENNESSEE VALLEY AUTHORITY w
U CH ATTANOOG A, TENNESSEE 37401 400 Chestnut Street Tower II May 11, 1982 CSf; IUD
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ts Director of Nuclear Reactor Regulation pE At'ention: Ms. E. Mensam, 011ef 9
Licensing Branch No. 4 4
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Division of Licensing U.S. Nuclear Regulatory Cannission Wasnington, DC 20555
Dear Ms. Adensam:
In the Matter of
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Docket Nos. 50-327
'Ibnnessee Valley Authority
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50-328 Enclosed is our response to your April 15, 1982 letter to H. G. Parris regarding the request for additional information on main steam line break. As requested in your letter, by carbon copy of this letter one copy of our response is being forwarded to:
Franklin Research center Attention:
R. C. Herrick 20th and Race Street Philadelphia, Pennsylvania 19103 If you have any questions concerning this matter, please get in touch with J. E. Wills at PIS 858-2683.
Very truly yours, TEM ESSEE VALLEY ti'
'*ITY
. M. Mills, Manager Nuclear Licensing T
Sworn to and subscrJped before me this //E day of M74ef-1982 l
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Enclosure oc:
U.S. Nuclear Regulatory Cannission (Enclosure)
Region II Attn: Mr. James P. O'Reilly, Regional A&ninistrator M
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101 Marietta Street, Suite 3100 p
Atlanta, Georgia 30303 p
8205170'686
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m RESPWSE '!O E. ADENSAM'S APRIL 15, 1982 IRrTER
'IO H. G. PARRIS REGARDING MAIN STEAM LINE BREAK (MSLB)
SEQUOYNIIUCLEAR PLANT NRC Request In the Sequoyah Final Safety Analysis Report (2), the response to question 6.56B states that the auxiliary feedwater (AEW) system is manually realigned by the operator after 10 minutes. In order to aid in the ocmpletion of our review, please provide the following information concerning your analysis of containment pressure response to un MSLB wid1 continued feedwater addition:
1.
Provide the actions required to be performed by the operator to prevent' exceeding containment design pressure and provide justification for the time at which credit is taken for operator action.
2.
Provide the time after the start of an MSIB when containment design pressure will be exceeded if no operator action is taken to terminate the accident. Provide the magnitude of the peak pressure and the time at which the peak occurs.
TVA Response Item 1
% e only action required of the operator to prevent exceeding containment design pressure following an MSIB is isolation of AIW to the affected steam generator. % e time at which credit is taken for this action is 10 minutes.
As stated in the response to question 6.56B part 2(e), information is available to the operator inmediately upon initiation of the accident. It is also stated that this information is given in BOI-2 and that operator action to terminate AEW flow to the affected steam generator will occur in approximately three minutes. Please note that the postulated accident involves conpletely blowing down one steam generator. %e pressure in this steam generator will drop to about zero psig while the pressure in the other three will be over 200 psig. We believe the operator will be able to identify the faulted loop with relative ease and quickness given such information.
Werefore, the assunption that operator action occurs at 10 minutes, which is consistent with the licensing basis of the plant, is justified and is in fact conservative.
Following an MSLB, both trains of RHR spray will be available to relieve containment pressure since no RHR flow through the reactor is needed.
However, no credit is taken for RHR spray in the analysis and the operator is not required to use it.
Item 2 A new analysis would be necessary to predict containment pressure as a function of time following an MSLB without operator action to isolate APW within 10 minutes. We do not believe such an analysis is justified.
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