ML20127A144

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Summary of 820210 Meeting W/Util Re Open SER Item Concerning Flooding in Cooling Tower Areas
ML20127A144
Person / Time
Site: Waterford Entergy icon.png
Issue date: 02/18/1982
From: Gonzales R
Office of Nuclear Reactor Regulation
To: Lear G
Office of Nuclear Reactor Regulation
Shared Package
ML19263A633 List:
References
FOIA-84-455, FOIA-84-A-56 NUDOCS 8203040058
Download: ML20127A144 (7)
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  • q,, UNITED STATES 8 NUCLEAR REGULATORY COMMISSION

{ WASHINGTON. D. C. 20555

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FEB ! 0 1992 Docket No. 50-583 MEMORANDUM FOR: G ge Lear, Chief ydrologic and Geotechnical Engineering Branch Division of Engineering THRU: Myron Fliegel, Leader. Hydrologic Engineering Section p Hydrologic and Geotechnical Engineering Branch

  • Division of. Engineering FROM: Raymond Gonzales, Hydrologic Engineering Section Hydrologic and Geotechnical Engineering Branch i

Division of Engineering

SUBJECT:

MEETING

SUMMARY

Plant Name: Waterford Steam Electric Station Licensing Stage: OL Responsible Branch: LB No. 3, S. Black, PM On February 10, 1982, we met with the applicant, Louisiana Power and Light D and its consultant, Ebasco, to discuss an open item in the SER concerning D flooding in the Cooling Tower areas. The enclosed is a summary of this meeting together with a list of attendees.

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aymond Gonzales h

F Hygrologic Engi ring Section Hfdrologic and Geotechnical hW Engineering Branch Division of Engineering

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Enclosure:

As stated cc: P.. Vollmer 0. Chopra J. P. Knight J. E. Knight

, S. Black J. Wemiel M. Fliegel M. Fliegel R. Gonzales R. Gonzales T. Chang i

M. Haughey '

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+ 4, J Meeting Summary Waterford Steam Electric Station February 10, 1982

Background

In the SER-OL - July 1981, we detemined that safety-related equipment in the g cooling tower areas were susceptible to flooding during extreme precipitation events. As a result, we took a position specifying levels (depths) to which all safety-related.equiprgent had to be protectedhas an alternative we stated that lower ponding levels would be acceptable if larger sump pumps were used or if the applicant could provide adequate assurances that roof drains would not be blocked during a design basis rainfall event.

Subsequently, the applicant proposed to reduce pondin'g levels by allowing ponded water to flow from the cooling tower areas a'nd pond in the Fuel ,

Handling Building. This would result in a lower depth of flooding because the accumulated volume 6f water would spread over a larger floor area.g addition, a discussion of the potential for clogging of roof drains was provided together with a revision to the FSAR stating that the sump pumps already installed in the cooling tower areas were,laroer than what had been i N -

stated initially in the FSAR. We reviewed the applicant's submittals and perfomed independent analysis. This showed that ponding levels in the Cooling Tower Areas, due to Probable Maximum Precipitation (PMP), would be l he level at 511ch safety-related equipment located on the floors of the coolir.g tower areas would be affected.

Early in the review process (Q-l's) we had told the applicant that in addition to considering PMP as a design basis event, it also had to consider a less s y e rainfall event coincident with an 0BE which would fail the sump i

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_2 pumps. The applicant stated that the sump pumps were seismically qualified so a seismic event would not affect them. However, when we requested that the sump pumps be included in the Q, List, they were listed as seismically designed but not seismically qualified. We then requested that a flood analysis be performed assuming that a less severe rainfall event than the PMPoccurscoincidentwithanOBEthalfailsthesumppumps. Jnresponse, the applicant performed a probability analysis showing that the combined probability of a rainfall event coincident with an OBE was less than required for design of nuclear power plants. In our evaluation of the applicant's analysis we did not agree with some of the assumptions made by the applicant so we concluded that a rainfall event less severe than the PMP coincident'

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with an OBE had to be considered. The applicant's analysis of this combination of events showed that ther,e would be flooding of safety-related equipment about

  • 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> after ponding in thee .cooling to..wer_ areas began. The appli_ cant felt that

. this would provide sufficient time to reactivate at least one of the failed sump pumps. There was no description however,of how the sump pumps would be reactivated or how long it would take to do so. The staff was unable to l

conclude that a rainfall event coincident with an OBE would,not result in flooding of some motor-control centers located in the cooling tower areas.

Meeting '

The meeting was held to discuss our concerns and possible solutions to the problem. After considerable discussion, it was decided that there are several solutions that the applicant will consider. These are:

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1) The applicant can perform the necessary analysis to show that the sump

, , pumps wi11' withstand an OBE. Representatives of EQB discussed what would be needed by NRC for review. The applicant must also show that the discharge pipes leading from the sump pumps will also withstand an

OBE.

'2) -The applicant can keep portable pumps on site for use in case the sump pumps are incapacitated. The applicant must describe the procedures to assure the pumps availability when needed and procedures which would.

be followed in utilizing the portable pumps.

3) The applicant can build an enclosure around and over safety related eq'uipment to prevent flooding of critical components. .Possible inundation of the motors of the inplace sump pumps must also be considered in this case if higher ponding levels are expected.

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In the FSAR, the applicant stated that in the event of the loss of off-site power, the sump pumps will be manually switched to the diesels. However, a L procedure describing-how this will be done has not been provided. This was discussed at this meeting and the applicant comitted to providing NRC a

-description of the procedures that will be used to assure that the sump pumps are functional during loss' of offsite power.

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Attendees-Waterford Meeting February 10, 1981 NRC/NRR S. Black LB-3/DL .

T. Y.iChang EQB/DE M. Haughey EQB/DE

-Om Chopra PSB/DSI J. E. Knight . .PSD/DSI J. Wermiel ASB/DE M. Fliegel HGEB/DE ,

R. Gonzales . HGEB/DE LP&L R. Foley Ebasco J. Hart J. Healey D. Hunter -

.I. Sydoriak W. Wittich

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