ML19206B138
| ML19206B138 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/22/1975 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Muller D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7905070451 | |
| Download: ML19206B138 (11) | |
Text
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SE? : : 375 Distribution:
. Q Central Files NRR/ Reading File SA3/ Reading File Daniel R. Muller, Assistave Director for Environr. ental Projects, RL HYDRCLOGIC DIGDTEERDIG DES INPU"'
PLA2.*? NAME: Ihree Mile Island Nuclear Generating Station. Unit 2 LICE'iSDIG STAG : OL DOCK 2T NUMBER:_ '!O "t?k RESPCIISI3LE 3F.ANCH: Environmental Projects 3 ranch #4 REQUESED CCMP'_L"."ICS DATE: Sep ter.ber 23, 1975 R."TII'4 STATUS : Hydrologic Engineering Sectien, SA3 - AtC ting Cct=ents on DES Enclosed for your use in preparing the Draf t Environmental Statecent is Hydrologic Engineering Input, prepared by T. Johnson and W. 31 vins. We have included short su::r. aries for the subsections requested by the EPM.
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F.arold R. Denton, Assistant Director y
for Site Safety Div ;siot of Technical F.eviev Office of Nuclear Raactor Regulation 1-
Enclosure:
As stated cc: w/o encl.
R. Boyd W. Mcdonald J. Panzarella v/enci.
S. h u uer R. Hein*u n H. Denton SS Branch t'Mefs D. Crutchfield W. Regan J. Norris T. Johnsor n'
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e HYDROLOGIC E!!GI::EERI::C des I,s;pg7 THREE MILE ISLUD ?!L' CLEAR GE::EPaTn:c 57a7;g;;
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2.5 Hvdrolorv 2.5.1 Surface '.later Hvdroloev The Susquehanna River has a drainage atea of approximately 25,000 square niles above the site and is rather extrene in its flow charceteristics.
Following is a summary of data as recorded 11 river miles upstreat at the Harrisburg gage:
Minimum daily flow 1,700 cfs Average annual flow 34,0C0 cfs Mean annual flood 300,000 efs Maxinu= ficod 1,020,000 cfs The main tributaries in the vicinity of the site are the following:
Str('3 Drainate Area Averaze Annual Discharge Conodoguinet Creek 483 sq. ni.
594 cfs Yellow 3reeches Creek 227 sq. mi.
290 cfs Swatara Creek 567 sq. mi.
935 cfs Conewago Creek (h'est) 510 sq. ni.
579 cfs Additional data on the seascnal flow variation and frequency of low flows are given in E2 Figures 2.5-6 and 2.5-7, respectively.
Because of the threat of flooding, the station is to be protected from floods up to those with flow rates of 1,100,000 cfs by an extensive dice systen around the island. On June 24, 1972, rains frca trcpical storn Agnes resulted in a ficod volume of about 1,000,000 cis, considarably in en:c_s of the pr2vious naximum recorded ficod of 740,0C0 cfs in 1226, 0GD o ',
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but below the prabable maximum ficod for the Three "ile Island location.
For floods greater than the levee design ficod and up to the probable maximum floed (1,625,000 cf s), the Station is designed to be shut down and waterproofed; the dike is designed to allow wcter to back into the plant area frc: the downstrea (southern) end of the island. An evaluation of flooding potential and the dike erosion protectica may be found in the staff's safety evaluation report.
The river and the streams in the vicinity are presently used for water supplies, both public and industrial, power generation, boating, fishing, and recreatien. Sport fishing is done in all streams in the general area of the site; however, there is no com ercial fishing. The applicant has identified 11 downstrea surface aater users within 50 miles of the site.
The nearest user of surface water is five alles downstream.
Approximately 1155 cfs is withdrawn from the river at this location b;. the 3 runner Island stea -electric generating station; a pcrtion of the eith-drawal is used as potable water.
A pumped storage facility consisting of two reservoirs and dans is propcsed for completion in 1983-8' on Stony Creek, appronizately 13 miles north-east of Harrisburg and upstrea of Three Mile Island. Detailed design data are not yet available for the project.
The project will, houaver, afford some degree of low flow aug=2ntation for the Susquehanna Ri'.ar.
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,rou,a ater Hvdrol ;y Grounduater occurs at TMI under water table conditicas.
The water table raa:hes its naximum elevatica at the highest topographic point in the cen:er of the island and falla off tcward both shores. A variation of about 5 feet occurs from eitner s1ce to the center, produc_4ng a gradient of approxinately 0.o percent toward the river. At observatien points in ans surrounding the plant area, water levels occurred generally at a depth in excess of 15 feet and ranged from l' to 19 feet.
The groundwater level occurred at a maxinun of 6.2 feet above the top of rocks with less than 1 foot of head existing above the soil-rock interf ace a t one point of observation.
The water level of the Susquehanna River, nornally flowing at elevation 278 feet, controls TMI groundwater levels.
Infiltration of grcundwater from the Station into the underlying Gettysburg shale and transmission to onshore water supplies is unlikely, since groundwater levels are higher en either river shore than on the island, with hydraulic gradients sloping toward the river.
2.5.3 Water cuality Water quality data for the Susquehanna River has been collected fron 1962 through 1971 by the Pennsylvania Department of Health.
The data are given in ER Figv. ras 2.5-1 through 2.5-a.
Cata en analyses of Susquahanna River war;c at the site, taken by Gilbert Associates, Inc., are given in Figures 2.5-5 through 2.5-8.
Table 2.5-1 of the ER supplenent ;i-e a s additional eater quality data f rom April 197 4 through Augus t 197a.
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3.3 Plant 'later Use The =ajcr ::ater require = cats of the plant are due to evnpo-ction, drift, and blowdown from the natural draft couling towers. The cooling vatar is taken f rom the Susq,:ehanna River at a maximum rate of 5'+,500 gpm (for both units).
River ; eater is also evaporatec by the mechanical draft cooling towers and is used to dilute the treated radwaste before dishcarge to the river.
Natural draft cooling towers have been constructed to dissipate the heat rejected from the turbine cycle.
The circulating water is recycled and chemically treated.
Befora discharge to the rivar, the heated water is cooled in rechanical draf t cooling towers, which are operated in such a manner as to return water and wastes to the Susquehanna River at appronimatel, the sa:e te=perature as the river.
A diagran showing plant water u e is given in ER Figure 3.4-1.
6.1 Precaerational Prograns 6.1.1 Hydrological The physical paraceters of the Susquehanna River near the plant site, such as temperature, conductivity, oH, dissol7ed oxygen, turbidity, color, odor, and other chemical properties have been studied since 1962; the data are given in ER Figures 2.5-1 through 2.5-3.
Additional data are given in Table 2.5-1 of the ER Supp12:ent.
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