ML19308E104

SER Input for Facility from Site Analysis Branch

ML19308E104
Person / Time
Site:	Crystal River
Issue date:	01/24/1974
From:	Hawkins E, Hulman L US ATOMIC ENERGY COMMISSION (AEC)
To:
Shared Package
ML19308E101	List: ML19308E100 ML19308E104
References
NUDOCS 8003200827
Download: ML19308E104 (6)

Text

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~ HYDROLOGIC' ENGINEERING

SUMMARY

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CRYSTAL RIVER UNIT 3 NUCLEAR GENERATING PLANT DOCKET NO. 50-302 2.4 Hydrologic Description The' site is in northwestern Florida on the Gulf of Mexico, some 67 miles north of Tampa, 40 miles southwest of Ocala, and about 3.8 miles south of the mouths of the Withlacoochee River and the Cross Florida Barge Canal. Cooling water intake and discharge channels have been dredged as much as about eight miles into the Gulf with' dredgings disposed in spoil bank islands along the channels. The southerly intake channel is also used for shipment of fuel to the two fossil units located i= mediately gulfward of the nuclear unit.

The slope of the continental shelf offshore is very mild with natural depths of 10 feet or less generally more than 8-10 miles i

from the plant.

l Topography in the plant vicinity is very flat and storm surges in the Gulf can cause extensive low land flooding. A nuclear plant island has been constructed by the applicant for the reactor, control, auxiliary, diesel, and turbine buildings; fire service pump house; l

I main transformers, and storage facilities for diesel fuel oil and water.

All safety-related facilities associated with the maintenance of l

l shutdown are on the nuclear plant island. The suitchyard, necessary for nor:a1 operation, is at elevation 98 feet, Crystal River Datum.

Zero (0.0) feet, U.S.C.&G.S. mean low water (MC?) datum is equivalent to l

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'88.0 feet, CRD.. Existing grade around the island.is elevation 98'-

feet CRD (10.0 feet' MLW). Grade level on'the island-is elevation.

118.5 feet'CRD (30.5-feet MLW). The crown of the service road around-the~islandhis 0.5 foot higher than the island grade.

Both public and private water supplies in:the site area are derived from ground water.

2.4.2 Floods The flood potential from several sources was investigated by-the applicant and the staff; stream and/or river flooding, site drainage, and hurricane-induced surges.

Local stream or river flooding is not considered a threat to the-3 plant because of the relative locations, slopes, and elevations of i

streams with respect to the plant and its raised nuclear plant island.

Site drainage for the nuclear plant island has been designed for a maximum rainfall rate of 10 inches per hour; somewhat-less than could occur during a local' probable maximum storm. However, drainage in the vicinity of safety-related' structures has been sloped away from the structures to preclude pondage, -even during a local probable maximum storm. Roof drains have.been designed to discharge directly

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into the site storm drainage system without roof ponding for rainfall intensities up to 6 inches per-hour. For ponding that could 7

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f 7 occur for more severe rainfall intensities of probable maximum; severity, 'the - applicant has concluded that roof ' structures will-support the ponded water.-

During. the PSAR, analyses of hurricane flood potential for the site were performed based upon preliminary ESSA (now NOAA) Hydro-meteorological' Branch estimates of probable maximum hurricane (PMI) parameters. The construction permit Safety Evaluation Report, dated June 6,1968, stated "The applicant has stated, and we will require, i

that the plant protection will conform to the applicable portions of revised ESSA criteria." The estimated maximum hurricane-induced surge level at that time was 109.4 feet CRD (21.4 feet 11W) with

.vave heights up to 9.0 feet higher.

Based upon detailed studies of

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surge-levels which could result from presently accepted NOAA PSI parameter estimates, the applicant proposed a maximum stillwater level I

of 117.4 feet CRD (29.4 feet m.W) with wave runup to elevation 123.5 l

feet CRD (35.5 feet MLW). We and our consultant, the U.S. Army Coastal Engineering Research Center (CERC), each reviewed the applicant's analysis in detail and independently estimated that the maximum surge-induced still-water level could reach elevation 121.4 feet CRD (33.4 feet 31W) with correspondingly more severe wave action. Our' consultant's report is l

contained in Appendix The staff required the applicant to provide protection against the higher stillwater and wave level estimates made by

.the staff and our consultant. As part of that protection, water-proofed doors are provided at vulnerable accesses to safety-related L

structures, a low vall is provided around a portion of the north and-

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-west sides of=the turbine building, a stepped reinforced concrete

= cap'is.provided around.the south,;and a portion of the west, slopes of the nuclear island,1 diesel fuel oil facility exposures are protected, and a technical-specification requiring plant shutdown

.and emergency procedures in anticipation of severe hurricanes will be employed. The applicant estimated the maximum wave runup level on exposed portions of safety-related structures for the higher surge level would be elevation 127.0 feet CRD - (39.0 feet MLW),~ and has provided assurances that the static and dynamic effects of such water-levels will not adversely affect safety-related structures.

We concur in the applicant's wave runup estimate, and conclude that safety-related structures, systems, and compenents are adequately protected from severe flooding, providing that the plant.is shutdown in anticipation of severe hurricanes.

2.4.3 Water Supp1v Safety-related water supply is to be taken from the intake channel via pumps located inside buildings located on the nuclear island.

The. pumps are thus protected from'ficoding in the same manner as other safety-related facilities. Minimum pu=p water level requirements are 70.9 feet CRD (-17.1 feet ML.?) in the nuclear island building e

i sump and, at a conservative slope of -one foot per mile, 79.0 feet CRD i

t-(-9 feet MLW) at the entrance to the intake channel-eight miles out i

in the Gulf. The applicant estimated that the probable minimum icw water level 1at the entrance of the channel would be 83.3 feet, CRD I

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(-4.7 feet,-MLW). This estimate was based upon the water _

level that.would result from.a PMH oriented to produce maximum sustained offshore winds blowing away from the' plant and channel.- We conclude that sufficient water level margin exists such that safety-related water supply will be available, even under-the most adverse hurricane conditions. This conclusion is based upon the assumption that the intake channel will be periodically surveyed and dredged as necessary to preclude blockage at low water levels.

2.4.4 Ground Water Ground water in the site area occurs in small shallow pockets of relatively-small areal extent, and in the large, extensive, and deeper Floridan artesian limestone aquifer.

In some areas the Floridan cutcrops in the form of springs.

Ground water mapping in the site vic'inity indicates ground ' water moves toward the Gulf to the west and southwest, and away from potentini users. The water table conditions at the plant site have been estimated to vary with tide levels in the Gulf and are generally at or_ near elevation 90 feet, CRD (2 feet MLW). The permeability of soils and rock at the site are very high and are typical of the region.

2.4.5. Conclusions-l The staff concludes that adequate flood protection fron severe hurricanes will be provided, that heavy local or regional-rainfall should not adversely affect the plant, that sufficient water uill be m

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