ML20117L847

Forwards Rev 0 to Mark I Wetwell to Drywell Differential Pressure Load & Vacuum Breaker Response.... Addl Info Re Predicted Dynamics of Facility Wetwell to Drywell Vacuum Breakers Provided,Per 850422 Request

ML20117L847
Person / Time
Site:	Peach Bottom
Issue date:	05/14/1985
From:	Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Stolz J Office of Nuclear Reactor Regulation
Shared Package
ML20117L850	List: ML20117L847 ML20117M127
References
NUDOCS 8505160410
Download: ML20117L847 (2)

Text

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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 (215) 841-4 5o 2 JOHN S. KEMPER VIC E #R ESID E NT

.................... May 14, 1985 Mr. John F. Stolz, Chief Docket Nos. 50-277 Operating Reactors Branch #4 50-278 Division of Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Conmission Washington, DC 20555

Subject:

Peach Bottom Atomic Power Station, Units 2 & 3 Wetwell-to-Drywell Vacutm Breakers Design and Analysis Clarification

References:

a) Letter - d. F. Stolz/NRC to E. G. Bauer, Jr./PECo, dated 4/22/85 b) Continutm Dynamics, Inc. Report No. 84-3, Rev. O, dated February 1984 - Mark I Wetwell to Drywell Vacutrn Breaker Load Methodology c) Continutm Dynamics, Inc. - Technical Note No. 84-11, dated October, 1984 - Response to NRC Request for Additional Infonnation on Mark I Containment Program Wetwell to Drywell Vacutm Breaker Load Methodology, Report No. 84-3, rev. O d) Continutm Dynamics, Inc. - Technical tbte No. 84-14, dated January 1985 - Mark I Wetwell to Drywell Differential Pressure Load and Vacutm Breaker Response for the Peach Bottan Atcmic Power Station - Units 2 & 3

Dear Mr. Stolz:

In response to your letter dated 4/22/85 Cref. a) requesting additional infonnation concerning the predicted dynamics of Peach Bottom wetwell to drywell vacutm breakers, we offer the fo11cwing:

Question 1 Is the chugging source rate used in the Peach Bottom evaluation the same as the one developed in CDI Report

1. 84-3?

Answer Yes. The methodology followed in CDI Report No. 84-3 Cref.

b) is identical to the methodology used in the Peach Bottom evaluation (ref. d) and detailed in response to question 5 from the NRC (ref c). /

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8505160410 850514 b ' I PDR ADOCK 05000277 P PDR

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--~ '  ; Question 2 Did the Peach Bottom calculation apply the 1.07. Toad factor-t; to' account for the uncertainty in calculating the -

- , underpressure?

" Answer Yes. - The 1oad factor used to assure conservative prediction of the underpressure.and~ detailed in response to question 2

-from the NRC Cref. c),-was applied to the Peach Bottom evaluation (ref.-d).

. Question 3-Do the Peach Bott e calculations use the drywell model which would result in the most conservative prediction?

' Answer Yes. Drywell modeling.was examined in response to question

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6 from the NRC (ref, c). For the Peach. Bottom evaluation -

Cref. d), the acoustic. volume moael results in a more conservative forcing function and was therefore used.

A' copy of reference (d) is attached. We understand that copies-of references (b) and (c) are already avaliable to you.

Please contact us 'If you need any further information.

Sincerely,

, $f A

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