ML20138G541

Affidavit of RG Wescott Re Hydraulic & Hydrologic Aspects of Rl Anthony Motion to Reopen Record on Info in LER-85-080 & to Stay Operation of Unit 1

ML20138G541
Person / Time
Site:	Limerick
Issue date:	12/11/1985
From:	Wescott R Office of Nuclear Reactor Regulation
To:
Shared Package
ML20138G537	List: ML20138G533 ML20138G541 ML20138G548
References
OL, NUDOCS 8512160349
Download: ML20138G541 (4)

Text

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE COMMISSION In the Matter of )

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PHILADELPHIA ELECTRIC COMPANY ) Docket Nos. 50-352

) 50-353 (Limerick Generating Station. )

Units 1 and 2) )

AFFIDAVIT OF REX G. WESCOTT I, Rex G. Wescott, depose and state that:

1. I am employed by the Nuclear Regulatory Commission as a

. hydraulic engineer with the Engineering Branch, Division of BWR Licensing, .

.0ffice of Nuclear Reactor Regulation. My duties include the hydrologic engineering review of nuclear generating facilities including flood vulner-ability, adequacy of water supply, and surface and groundwater acceptability of effluents.

2. The purpose of this affidavit is to address the hydraulic and hydrologic aspects of R. L. Anthony's motion to reopen the record on in formation in LER 85-080 and to stay operation of Unit 1 of the Limerick Generating Station.

3. In March of 1984 I testified before the Atomic Safety and

, Licensing Board regarding the hydrologic effects of a postulated cooling tower basin failure. In my testimony I concluded that in the event of failure of either of the two cooling tower basins, only a small amount of water would be capable of entering the turbine building. This conclusion was based on a site visit by the Staff, some simple calculations of outflow 7^

H512160349 851213 DR ADOCK 050003 2 L.__

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from the basins and flow over the plant yard, and the plant final grading and building locations as shown in,the Licensee's FSAR.

Due to the continuing incomplete construction status of Unit 2,

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temporary structures that would tend to reduce outflow ~ from primarily the east side (Unit 2 side) of the plant yard are still in place and may remain

'in place until plans for Unit 2 construction are finally detennined and implemented. The effect of these temporary buildings is:to slightly increase the water level, primarily in the vicinity of the Unit 2 turbine building, that would result from tha basin failure event and the local intense probable maximum precipitation (PMP) event over the water level that would occur if grading and buildings were in accordance with the FSAR.

5. When the Licensee discovered this situation'and its implications, barriers to the flow-of water into the Unit 2 turbine building were placed outside and within the Unit 2 turbine 'ouilding to provide passive flood protection. --The Licensee's architect-engineer, Bechtel Power, Inc., also performed calculations to determine:

1) the depth of water on the north and east sides of the Unit 2 turbine building resulting from the PHP on the plant site,

2) the depth of water on the north side of the turbine building.resulting frorr the failure of one of the cooling

.. tower basins, and

3) the dynamic force against the north side of the turbine ,

i' building resulting from the failure of a cooling tower basin.

6. I was not able to independently verify the first two analyses because of the complexity and data required. I did, however, discuss the calculations with the ' Licensee's engineer in regard to assumptions and I conclude that the Licensee's approach is valid and the procedures.

results of its calculations are reasonable; that is, the PMP will be the controlling event and will result in a peak water level of el 218.3 ft.

(1.3 f t. above plant floor level) and remain above floor level for about two hours. The cooling tower basin failure will result in approximately the same maximum level but will remain above floor level for about thirty minutes. The barriers that the Licensee has installed on the openings that previously provided the greater. opportunity for entry of water protect these Unit 2 turbine building entrances up to el 220 ft. (3 ft. above the floor level, el 217 ft.).

7. I have also independently verified the third analysis, which I believe to be the most important one. Both the Licensee and I concluded

-that in the event the flow from the basin failure was able to move directly toward the turbine building, most of the kinetic energy gained from the downhill flow would be dissipated in a ' hydraulic pump (transition from supercritical flow to subcritical flow) before impinging on the turbine building. Hence, the forces on the gates and walls of the building will be primarily hydrostatic (standing water) and well within the allowable

, forces for either the gates or the building walls.

8. I also wish to confirm that, consistent with my earlier testi-mony, a suitably conservative assumption for a breach of the cooling tower basin wall is a 50-foot breach located at such a point in the 1532-foot circumference of the basin wall that it directs the flow of water toward the turbine building.

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9. I conclude, based on an onsite inspection of the plant exterior, that it is highly unlikely that a breach in either tower basin could result in high velocity flow directed at the turbine building.

10. Based on my site visits to the plant, my discussions with the Licensee, and my own calculations, I would not expect water to enter the turbine building in quantities sufficient to cause significant flooding of the building through e'i ther a failure of a cooling tower basin or a '

local intense precipitation event.

11. The Licensee has committed orally to update the FSAR in a forthcaning revision to reflect the yard grading in the vicinity of.the Unit 2 turbine building in the interim construction period and to provide a summary of its hydrologic analyses.

The foregoing information is true and correct to the best of my knowledge and belief.

Rex G. Wescott YW Subscribed and sworn to before me this //M day of M , 1985 M

Notary Public My commission expires: /f(,

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