ML20210S905
| ML20210S905 | |
| Person / Time | |
|---|---|
| Site: | Satsop |
| Issue date: | 06/27/1975 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Deyoung R Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-1699 NUDOCS 8605290503 | |
| Download: ML20210S905 (8) | |
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WEB ASTISE PLAleNB ON PROJECT: N/A assCRIFT305 Of 33550585: Name RETIN SEAIUS: Meteorelegy Seetica. S&B - Osep1ste w h in the Safety i
Basleeed to the esteesolaar mesties Aspes aer Evelesties Report em the subject plant. The app &$ essa hee met psevided j
the 46-hour Pseh e le Mesimmi Winter Prealpisettes M ).' esaded te assess the entreme envireemental esedities seew wate t en the neofs of eefety-seleted buildissa, se regnested by the staff. 1estead, the applicent hoe w' ' by staties that the 40-heet WW de da emesse of the 50 penede/equere feet deety same need esed 8er the plant. assed i
en the taformaties so for psevided by the applieset, to staff esealedes that the applieset hee met dessestrated the adequesy of the destas seaw lead for the entreme envireemental eseditism.
This seettee wee prepared by R. Karossiewies & E. E'.-Moshes, Jr., Site i
Aeolysie Brenek. TR.
8'thof W ty R.R.Seems Earold R. Bestem, Assistsat Direster for Site Safety Divisies of T h 1 Braiew OffLes of Wesleer Beaster Regulaties Reelecers:
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WASHINCTON PUBLIC POWER SUPPLY SYSTEMS NUCLEAR POWER PROJECT NO. 3 - UNITS 3 & 5 DOCKET NUMBERS 50-508 & 50-509 SAFETY EVALUATION REPORT
- INPUT 2.3 Meteorology Information concerning the atmospheric diffusion characteristics of a proposed nuclear power plant site are required in order that a determination may be made that postulated acciiental, as well as routine operational, releases of radioactive materials are within NRC guidelines. Further, regional and local climatological information, including extremes of climate and severe weather occurrences which may affect the' safe design and siting of a nuclear plant at a proposed site, is required to insure that safety-related plant design and operating bases are within NRC guidelines. The meteorological characteristics of a proposed site are determined by the staff's evaluation of meteorological information in accordance with the procedures presented in l
Sections 2.3.1 through 2.3.5 of the USNRC Regulatory Standard _
Review Plan.
j 2.3.1 Reaional climatology i
The applicant has provided an adequate description of the regional meteorological conditions of importance to the safe design and l
siting of this plant.
l The climate of western Washington is characterized by warm, dry summers and mild, wet winters. During the autumn and winter, frequent maritime weather disturbances from the Pacific Ocean cross the Washington coast and result in nearly continuous cloudi-ness and almost daily precipitation. In the spring, the semi-permanent Pacific Anticyclone (Eastern Pacific High) moves north-eastward and begins to influence weather conditions over western Washington. By summer the presence of this system has reduced the number and frequency of weather disturbances in the region so that periods of 20 days without measurable rainfall are not unusual.
The proximity of the Pacific Ocean moderates temperatures over l
the region so that annually temperatures above 90F may be expected on only about five days. Temperatures below 0F occur less frequently than once in every 10 to 20 years. On 80 days annually temperatures below 32F may be expected. Precipitation annual averages vary throughoat the region, depending on topographic elevation, from 50 to 80 inches. The majority of the precipitation occurs during the f requent f all and winter rains. Snow occurs only periodically On an and usually does not accumulate to a significant extent.
annual basis relative humidity averages around 80 percent.
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, Severe weather occurrences in the site region are mainly associated j.
with severe thunderstorms. However, due to the moderating effects l-of the Pacific Ocean and the topography of the region, severe l
l-weather occurrences are relatively rare.
Three tornadoes were reported within the one degree latitude-l longitude square containing the site during the period 1955-1967, giving a mean annual tornado frequency of 0.2 and a reccurrence l
l interval for a tornado at the plant site of 5000 years. There was only one windstorm with wind speeds of 50 knots (58 mph) or greater reported within this one degree square during the same period and no reports of hail measuring three-quarters of an l
inch in diameter or larger. A severe ice storm (accumulation of one inch or more) can be expected during one year out of six or The maximum " fastest alle" wind speed recorded at Olympia, seven.
WA was 60 miles / hour, although " fastest mile" winds in excess of i.
100 miles / hour have been recorded at exposed locations on the Washington cost. High air pollution potential (air stagnation) can be expected to occur on.six days annually.
The plant design basis tornado, with a maximum wind speed of 300 miles / hour consisting of a maximum rotational wind speed of 240 miles / hour and a maximum translational wind speed of 60 miles /
hour, a maximum pressure drop of 2.25 psi, and a maximum pressure i
drop rate of 1.2 psi /sec, conforms to the recoussendations of Regulatory Guide 1.76 and is sufficient for the area of the country in which the plant is located. The design basis, sustained (fastest mile) wind speed of 105 miles / hour at a height of 30 feet with a return period of 100 years is also sufficient for the site, considering its inland location.
2.3.2 Local Meteorolony-The applicant has provided suf ficient information for us to make an adequate evaluation of the local meteorological conditions of importanco to the safe design and siting of this plant with the exception of the weight of snow on the roofs of safety-related buldlings that might occur during the extreme environmental condition.
Long-term weather records from Elma, WA, four miles northeast of the site show that the extreme maximum and minimum temperatures recorded there are 105F and 0 F, respectively. At Aberdeen, 15 t
l miles west of the site, the corresponding extreme temperatures are 105 F and 6 F.
At Olympia, 25 miles east-northeast, extreme maximum and minimum temperatures of 103 F and -1 F have been recorded.
A maximum 24-hour precipitation total of 4.93 inches has been recorded at Olympia and a 24-hour maximum snowfall total of 13.7 r
l-At Oakville, WA,13 miles southeast of the site, 24-hour inches.
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3 snowfall of 17.0 inches has been' observed. Thunderstorms may be expected to occur on about five days annually in the site vicinity and f reezing precipitation once each year. Heavy fog (visibility one-quarter mile or less) occurrences at Oylopia average 92 days annually. Wind data, collected at the 33-ft level onsite during the period May 1973 through April 1974 show that the predominant wind flow direction over the site at this level is from the southwest and west-southwest directions with frequencies of occurred least frequently (less than 1%).
Based on a temperature correlation study done by the applicant, at our request, between temperatures at the site and at Elma, the design basis temperature of 101.5 F for the ultimate heat sink is considered to be adequate.
Our position is that the weight of snow on the roofs of safety-related structures used for the extreme environmental load adequacey evaluation should be the total of:
l 1) the weight of the 100 year snowpack at ground Icvel, plus 2) the weight of the 48-hour Probable Maximum Winter Precipitation (PKWP) at ground level for the month corresponding to J
the selected snowpack occurrence.
The snowpack and snowfall should be adjusted for density differences, and all ground-level values should be adjusted to represent appropriate weights on roofs of safety-related structures such as by the methods described in ANSI A58.1(1972).
j The applicant has provided the 100 year snowpack for the site, which is acceptable. However, in response to our request for additional information concerning the weight of snow due to the PMWP the applicant, instead of providing the PMWP snow weight, stated that the 50 psf load used for the extreme environmental load is less than the 48-hour PMWP. Since the applicant has not provided the weight of the PMWP on the roofs of safety-related structures or satisfactorily demonstrated that the PMWP could neither f all as snow or ice nor remain entirely on top of or within the antecedent snowpack on the roofs, we have not been abic to assess the adequacy of the extreme environmental snow weight.
The information available to us at present indicates that the applicant's design is not adequate.
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4-2.3.3 Onsite Meteorological Measurements Program The onsite meteorological measurements program has been compared with the recommendations and intent of Regulatory Guide 1.23.
We concluded that the meteorological measurements program has produced data which, in turn, have been summarized to provide an adequate meteorological description of the site and its vicinity for the purpose of making atmospheric diffusion estimates for accidental and routine airborne releases of radioactive effluents from the proposed nuclear plant.
The applicant has installed a 60 meter high meteorological tower about 1100 meters north-northwest of the reactor complex, which became operational in May 1973. Wind direction and wind speed are measured at. the 10 and 60 meter Icvels on the tower and ambient air temperature and relative humidity at the 10 meter level.
Temperature dif ference is measured between the 10 and 60 meter levels. Precipitation is measured at ground icvel.
/.n additional instrument to measure relative humidity has been installed at the 60 meter level. All instrumentation conforms to the recommendations of Regulatory Guide 1.23.
The applicant has provided joint frequency distributions of wind speed and direction by atmospheric stability class (based on vertical temperature difference) from a one year period of data record (5/1/73 - 4/30/74) collected onsite. The wind speed and direction measured at the 10 meter level and the vertical temperature difference between the 10 meter and 60 meter icvel were the bases for our dispersion estimates. The joint recovery rate for these data was over 95%, which exceeds the Regulatory Guide 1.23 recommendation of a recovery rate of at Icast 90%.
2.3.4 Short-Term (Accident) Diffusion Estimates Conservative assentiments of post-accident atmospheric dif fusion conditions have bean made by us from the applicant's meteorological data and approprir.to diffusion modt-1s.
In the evaluation of short-term (0-2 haurs at the exclusion distance and 0-8 hours at the LPZ distance) nccidental releases from the plant building and vents, a ground-level release considering a building wake f actor, cA, of 1500m2 was assumed. The relative concentrations for the various time potiods following an accidental release were calculated using the dif fusion model described in Regulatory Guide 1.4.
The relative concentration for the 0-2 hours time period which is 3 at the exceeded no more than 5% of the timo is 1.0 x 10-3 sec/m exclusion distance of 1290 meters (measured from the outside edge of the containment building). This relative concentration is equivalent to dinpersion conditions produced by Pasquill type F
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, stability with a wind speed of 0.3 meters /str.ond. The relative concentrations estimated at the outer boundary of the low population zone (4830 meters) for the various time periods following an accidental release ares 0-8 hours 1.0 x 10~4 sec/m3 8-24 hours 6.7 x 10-5 sec/m3 1-4 days 2.8 x 10-5
..cf 3 4-30 days 7.7 x 10-6
,,cf,3 2.3.5 Long-Term (Routine) Diffusion Estimates Reasonable estimates of average atmospheric diffusion conditions
' ave been made by us from the applicant's meteorological data and appropriate dif fusion models as described in Regulatory Guide i
of 1.2 x 10~gghest of fsite annual average relative concentrat on 1.42.
The h sec/m3 for vent releases occurs at the exclusion distance north of the proposed reactor complex.
2.3.6 Conclusions The design basis tornado parameters used for the plant conform to the recommendations and intent of Regulatory Guide 1.76.
The design basis sustained (" fastest mile") wind speed used for the plant is considered adequate. The applicant's onsite meteoro-logical program conforms to the recommendations and intent of Pegulatory Guide 1.23 and has produced data which adequately describe site atmospheric dispersion conditions and which could be used by the staf f to make both conservative and realistic estimates of atmospheric dispersion characteristics for accidental and routine gaseous releases, respectively, from the plant.
The applicant has provided suf ficient information concerning meteorological conditions which are of importance to the safe design and siting of the plant with the exception of the weight of snow on the roofs of safety-related structures under the design extreme environmental condition. The information provided by the applicant to date indicates that the 50 poundo/ square foot weight proposed by the applicant is not adequate.
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F Bibliography - Meteorology Section
- Cross, E., 1970: The National Air Pollution Potential Forecast's Program. ESSA Technical Memorandum WBTM NMC 47, National Meteoro-logical Center, Washington, D. C.
llolzworth, G.
C.,
1972: Mixing lleights, Wind Speeds, and Potential for Urban Air Pollution Throughout the Contiguous Unite! States.'
AP-101, Environmental Protection Agency, Office of Air Programs, Research Triangle Park, North Carolina.
Iluschke, R. E.,1959: Clossary of Meteorology. American Meteorolo-gical Society, Boston, Massachusetts.
List, R. J. (ed.), 1971: Smithsonian Meteorological Tables.
Smithsonian Institution, Washington, D. C.
- Riordan, l'.,1973: Extreme 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> snowfalls in the United States:
Accumulation, Distribution, and Frequency. Special Report ETL-SR-73-4.
U. S. Army Engineer Topographic Laboratories, Fort Belvior, Virginia.
Sagendorf, J.
F., 1974: A Program for Eva}uating Atmospheric Dis-persion from a Nuclear Power Station. NOAA Technical Memorandum ERL ARL-42. Air Renources Laboratory, NOAA, Idaho Falls, Idaho.
SELS Unit Staff, National Severe Storms Forecast Center, 1969: Severe Local Storm Occurrences, 1955-1967. ESSA Technical Memorandum WBTM PCST-12, Office of !!eteorological Operations, Silver Spring, !!aryland.
Thom, 11. C. S., 1963 : Tornado Probabilitic.1. Monthly Weather Review, October-December 1963, pp 730-737.
Thom, 11. C. S., 1968 : New Distributions of Extreme Winds in'the United States. Journal of the Structural Division, Proceedings of the American Society of Civil Engineers - July 1968, pp 1787-1801.
U. S. Atomic Energy Commission,1974: Regulatory Guide 1..
Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for PressuriscJ Water Reactors - Revision 2.
USAEC, Directorate of Regulatory Standards, Washington, D. C.
U. S. Atomic Energy Commission,1972: Regulatory Culde 1.23, Onsite
!!eteorological Programs. USAEC Directorate of Regulatory Standards, Washington, D. C.
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2-U. S. Atomic Energy Commission, 1974: Regulatory Guide 1.42 Interim Licensing Policy On As Los As Practicable for Caseous Radioiodine Releases from Light-Water-Cooled Nuclear Power Reactors - Revision 1.
USAEC Directnrate of Regulatory Standards, Washington, D. C.
U. S. Atomic Energy Commission, 1974: Regulatory Guide 1.76, Design Basis Tornado for Nuclear Power Plants. USAEC Directorate of Regulatory Standards, Washington, D. C.
U. S. Department of Commerce, Environmental Data Service,1968:
Climatic Atlas of the United States, Environmental Science Service Administration, Washington, D. C.
U. S. Department of Commerce. Environmental Data Service Local Climatological Data, Annual Summary with Comparative Data -
Olympia, WA. Published annually.
U. S. Department of Commerce, Environmental Data Service: Storm Data.
Published monthly, Asheville, N. C.
U. S. Naval Weather Service, 1969: Worldwide Airfield Summaries.
Volume VIII, Part 1 United States of America (West Coast, Western Mountains, and Creat Basin). Federal Clearinghouse for Scientific and Technical Information, Springfield, Virginia.
WashingtonPublicPowerSupplydystem,1974: Preliminary Safety Evaluation Report, Nuclear Project No. 3 - Units 3 & 5.
Docket Numbers 50-508 & 50-509.
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