ML20214G786
| ML20214G786 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 08/25/1972 |
| From: | Harold Denton US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Boyd R US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| CON-WNP-0104, CON-WNP-104 NUDOCS 8605220503 | |
| Download: ML20214G786 (9) | |
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-e AUG 2 51972 R. 8. Boyd, Assistant Director for N R's, L HYDROLOGIC ENGDGERING BU) MARY FLANT NAME: Hanford No. 2 LICENSING STAGE:
DOCKET NUMBER: 50-37/
RESPONSIBLE BRANCH: BWR Br. #3 RMUESTED COMPIETION DATE: August.17, 1972 APPLICA1CS RESPONSE DATE NECESSARY FOR NEXT ACTION PLANNED ON PROJECT: N/A DESCRIPTION OF RESPONSE: N/A REVIEW STAR 13: Complete Enclosed is the Hydrologic Engineering Summary for your use in preparing the ACRS report and public safety evaluation on the cubject plant. The report was prepared by Mr. F. Kilpatrick of the USGS, while on ter:porary ascignment to this office, in cooperation with L. G. Hulman.
DISTRIBUTICH Docket File 397 #
L - Edg L:AD/SS - Edg Harold R. Denton, Acsistant Director L:SAB - Edg for Site Safety Directorate of Licensing Enclocure:
As stated w/oenclosure cc:
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W. Mcdonald i
cc: w/ enclosure
- 8. H. Hanauer J. Hendrie C. Long R. Clark S. Minor F. K12ratrick, USGS L. G. Hulman omcc>
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Form AEC-Sto tRes. 9-53; AECM 0240
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HYDROLOGIC EI;GINEERII;G
SUMMARY
HANFORD NO. 2 NUCLEAR STATION DOC. NO. 50-397 2.4 Hydrologic Engineering 2.h.1 Hydrologic Description - The plant is to be located approximately 12 miles north of North Richland, in Benton County, Washington, in the southeast area of the 575 square mile U. S. Atomic Energy Commission's Hanford Reservation, and about 3 miles west of the Columbia River.
The Columbia River starts in British Columbia and flows 1200 miles into the Pacific Ocean at Astoria, Oregon. There are 11 multi-purpose dams on the Columbia River and its tributaries, the two largest in the United States being Bonneville downstream of the site at river mile (RM) lLS and Grand Coulee upstreem at RM 597. The Hanford site is at about R5 352, downstream of the Priest Rapids Dam (RM 397) and upstream of McNary Dam.
The intake for the municipal water supply for the City of Rich-land is from the Columbia River about 11 miles downstream from the site. Extensive diversion of water is made from the Columbia upstream of the site for irrigation purposes.
The plant site is situated physiographically in the Pasco Easin, one of the larger sedimentary basins within the Basalt Plateau.
The underlying soils are dense and grandular in nature with the basalt bedrock existing at approximately elevation 20 feet mean sea level (M3L). Existing ground elevation in the site vicinity L
averages L39 feet Mst. Plant grade is elevation LL1 feet MSL.
The existing ground water surface is at about 378 feet M3L in the site area, sloping steeply eastward toward the Columbia River. Ground water levels fluctuate on the average of a half a foot per year. AEC contractors have drilled in excess of 1500 observation wells in the Hanford Reservation area.
Most wells are concentrated in the central section of the reservation in the vicinity of the chemical processing plants.
A description of these wells is to be found in the review for the FPIF. No private or domestic wells exist within h miles of the site other than two at the FFIF site for fire protection, procest and sanitary purposes.
Cooling water is to be provided via a closed loop cooling tower system with make-up water to be supplied via a Columbia
' River intake structure and connecting pipeline. In addition, I
two adjoining spray ponds will provide emergency cooling. The top of the spray ponds containment walls are at elevation L35 feet FEL. Make-up wate; fran the pipeline will supply both the spray ponds and cooling towers.
2.L.2 Floods 2.h.2.1 Historical Floods - The msximum flood of record occurred in 189h with an estimated peak discharge of 7kO,000 cubic feet per second (cfs), and was the result of combined snowmelt and rainfall runoff. The largest recent flood occurred in 19h8 with a peak runoff rate of 690,000 cfs. The water levels in the
Columbia adjacent to the site for the 189L and 19L8 floods are estimated to be elevations 373 and 369 feet M3L,respectively.
2.L.2.2 Probable Maximum Flocds on Columbia River - The appli-cant has estimated the effects of a probable maximum flood at the site using a detailed study by the Corps of Engineers in their memorandum report of September 1969, entitled " Lower Columbia River Standard Project Flood and Probable Maximum Flood". The reservoir regulated FMF peak discharge, as adjusted for the Hanford Site, was determined as 1,LLO,000 efs, producing a flood level of approximately 390 feet MSL. The Corps of Engineers' model used to estimate the PMF at the site is based on rainfall-snowpack-runoff-reservoir control relationships developed from historical flood analysis and actual reservoir cperating experience. The applicant has also found the effects of the proposed Ben Franklin Dam near the plant will not appreciably raise flood levels in the plant area to adversely affect main plant facilities.
based on the estimated PMF level of elevation 390 feet M3L, main plant structures are not considered susceptible to runoff type floods.
2.L.2.3 Local Probable Maximwm Floods - The applicant evaluated the local PLE for the drainage basin common to the reactor buildings and spray ponds, and the very localised spray pond area. These computations were based on generalized probable maximum precipitation estimates for the region made by the
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U. S. Weather Bureau (now NOAA) and reported in Hydrometeoro-logical Report No. L3 The applicant has determined that (1) the spray ponds can safely contain such a storm, and (2) the drainage swale immediately north and east of the plant is adequate to pass a local PMF from the 5.6 square mile drainage area north-west of the site without exceeding the h35 feet M3L elevation of the spray pond containment.
2.h.2.k Seismically Induced Floods - The applicant has evaluated the potential fer site flooding due to seismically induced failure of critically located large upstream dams such as Grand Coulee and Chief Joseph in the U.
S., and Mica and Arrow in Canada. Father than evaluate the seismic potential in the areas adjacent to al] the upstream dams, and then determine the respective espability of each structure to withs'.and severe earthquakes of a severity associated with nuclear facility design, the applicant has identified those structures whose arbitrarily assured failure mi ht result in the worst flood conditions at E
the Hanford 2 site. This very conservative method of analysis is noted as useful for identifying an arbitrary upper limit of seismically induced flood potential, but is not considered accurate enough to ascertain whether facilities at lower levels (or those closer to the river) might actually be exposed to such a flood risk. In other words, facilities located above the flood levels indicated by such an analysis should definitely be safe from such floods, while those at lower levels are not necessarily susceptible to seismically induced floods.
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-S-The two dams whose arbitrarily assumed, seismically induced, and independent failures were considered to evaluate the worst flood conditions at the site were Grand Coulee and Mica Dams.
To aid in the evaluation of the effects of the flood wave resulting from such failures, the applicant used existing analytical studies of artificial flood waves under various assumptions of catastrophic failure of Grand Coulee Dam, a separate conservative evaluation of the arbitrarily assumed failure of Mica Dam as far downstream as Grand Coulee Dam (by the Corps of Engineers), and an evaluation of the effects of the postulated Mica Dam failure caused flood wave on Grand Coulee Lam (by the Bureau of Reclamation). The applicant's conclusions are that all plant facilities, except the river intake structure, are well above the conservatively identified 4
seismically induced flood levels. The river intake structure, however, is not considered necessary for plant shutdown and cooldown in such a situation since that plant may be safely shutdown with water frem the cooling towers or spray ponds.
2.h.3 Groundwater - Presently groundwater levels are well below the foundation of any of the plant structures. Because of the possible future construction of the Ben Franklin Dam, and resultant raising of groundwater levels in the aquifer under the plant site, the applicant has agreed to waterproof the substructure of the reactor buildings. An extensive groundwater well monitoring system and the absence of any L
r-existing groundwater users in close proximity to the proposed plant may preclude any groundwater problems from both normal or inadvertent releases of radioactive liquids.
2.h.h Low Water Considerations - The applicant's analysis indicates that the lowest historical mean monthly flow, after modification of recorded flow data for irrigation uses, is 62,000 cfc. Minimum short term flows as low as 36,000 cfs may occur as the result of minimum upstream reservoir release commitments, or even lower during very extreme droughts.
Condenser cooling is to be accomplished utilising cooling towers requiring approximately 34 cfs for make-up. The river water make-up pumphouse is to contain 3 pumps normally utilised for supplying make-up water to the cooling towers. Although not required, the pumps are also designed to supply water for safe shutdown to the spray ponds. The pump intake system is designed to function down to 3k0 feet FGL, or below the minimum reservoir regulated low flow of 36,000 efs.
2.h.5 Heat Sink - The ultimate heat sink is to cc:.sist of two mechanical draft ecoling towers, the river make-up intake and pipeline, and two Class I seismic spray ponds. The spray ponds are sised to provide a minimum total storage supply for nore than 30 days cf chutdown and cooldown operation, independent of any make-up sources. Each pond, however, will have substantially
less than a thirty day supply. The thirty day minimum supply is based on reasonably severe summer meteorological shutdown conditions. A permanent interconnection between the ponds, however, is to be provided for transferring water between ponds, and portable pumps will be provided for backup use to assure the minimum 30 day supply. Water from the cooling towers and make-up fror he river serve as supplementary supply sources. The interconnecting river water make-up line to the cocling towers, and the cooling tower lines leading to the spray ponds are situated above the spray pond water surface such as to prevent back siphonage of the ponds.
2.h 7 Conclusions - We conclude that the plant will be able to withstand precipitation and seismically induced Columbia River floods, as well as local floods. Because of the relatively high site elevations and set-back fram the river, and the very conservative seismically induced flood analysis, we believe the applicant has dencnstrated that safety related plant facilities will not be flooded by such events. We agree with the applicant that the general direction of ground water movement is toward the Columbia River, and we believe that any inadvertent releases will migrate slowly toward the river. We agree with the appli-cant that adequate safety related water supply will be available from the cooling towers, spray ponds, and make-up water facilities.
This conclusion is based on our review of the effects en the
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ultilnate heat sink, taken as a whole, to withstand floods, tornados, strong winds, and the Class I seismic design criteria for the spray ponds.