ML20202H779
| ML20202H779 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/02/1999 |
| From: | Stephen Dembek NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| TAC-MA4431, NUDOCS 9902080228 | |
| Download: ML20202H779 (3) | |
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g February 2,1999 MEMORANDUM TO: Docket File '
FROM:
Stephen Dembek, Project Manager Project Directorate 1-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation
SUBJECT:
MILLSTONE NUCLEAR POWER STATION, UNIT 2, MILLSTONE NUCLEAR POWER STATION, UNIT 2, DRAFT REQUEST FOR ADDITIONAL INFORMATION, LOSS OF MAIN FEEDWATER TRANSIENT ANALYSIS (TAC NO. MA4431)
The attached request for additional information (RAI) was transmitted by facsimile on February 2,1999, to Ravi Joshi of the licensee's staff. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI and/or clarify issues that may not need a formal response from the licensee. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.
Docket No. 50-336 l
Attachment:
As stated
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%,,,,, 8 February 2,1999 MEMORANDUM TO: Docket File FROM:
Stephen Dembek, Project Manager Project Directorate 1-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation l
SUBJECT:
MILLSTONE NUCLEAR POWER STATION, UNIT 2, DRAFT REQUEST l
FOR ADDITIONAL INFORMATION, LOSS OF MAIN FEEDWATER i
TRANSIENT ANALYSIS (TAC NO. MA4431)
The attached request for additional information (RAl) was transmitted by facsimile on February 2,1999, to Ravi Joshi of the licensee's staff. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI and/or clarify issues l
that may not need a formal response from the licensee. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.
l Dockt,t No. 50-336 l
Attachment:
As stated 1 -
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l Stephen Dembek - ma43312.cpj Paga1l c.
g QUESTIONS RELATED TO THE NEW LOSS OF MAIN
. FEEDWATER 1 RANSIENT ANALYSIS MILLSTONE UNIT 2 TAC MA4331 Please verify that for the new FSAR Chapter 14 loss of main-feedwater transient analysis non-safety related systems or components (for example; the pressurizer PORVs, sprays and heaters and steam generator dump valves) are modeled to assure conservative results. In other words, please verify that these systems are modeled if j
they make the consequences worse and not modeled if they mitigate the consequences.
The new FSAR Chapter 14 pages indicate that two single failures were considered for the loss of main feed event. Please verify that these single failures represent the most
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limiting single failure for each case analyzed for this event.
Please verify that the auxiliary feedwater flow assumed in the FSAR Chapter 14 analysis is a minimum flow including uncertainties, rather than a best estimate flow calculated for the FSAR Chapter 10 analysis.
In accordance with the approved topical report, please describe how the conservative initial conditions for the analysis of this event were chosen. -In your responce please be specific only for the assumptions associated with the initial steam generator parameters and for the reactivity feedback.
i The DNB aspects of the loss of main feed are assumed to be bounded by the loss of j
forced reactor coolant flow event. In general, the staff does not find it acceptable for an
'I aspect of a " decrease in heat removal by the secondary system" to be bounded by a "
decrease in RCS flow event" (or any other different category event). The DNB transient I
for the worst " decrease in heat removal by the secondary system" event should be analyzed in the FSAR.
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