ML19329E151
| ML19329E151 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/31/1967 |
| From: | Crawford T, Knox J AFFILIATION NOT ASSIGNED, ARKANSAS POWER & LIGHT CO. |
| To: | |
| References | |
| NUDOCS 8005300742 | |
| Download: ML19329E151 (73) | |
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APPENDIX 2A REPORT EUVIROUME?!TAL STUDY IETEOROLOGY PROPOSED RUSSELLVILLE UUCLEAR UNIT NEAR RUSSELLVILLE, ARKANSAS FOR ARKANSAS POWER AND LIGHT COMPANY 0175 g
October 1967
TABLE OF CONTEITS SECTION TITLE PAGE 2A.1 INTRODUCTION 2A.1 Purpose of Report Organization of the Investigation 2A.2 SCOPE 2A.2 2A.3
SUMMARY
AND CONCLUSIONS 2A.3 Two-Hour Model Twenty-Four Hour Mcdel Thirty Day Model 2A.4 SITE LOCATION AND CLIMATOLOGY DATA SOURCES 2A.5 Site Location -- Description Meteorological Data Sources in Site Vicinity Discussion of Weather Data 2A.5 GENERAL SITE CLIMATOLOGY 2A.9 Surface Temperature Precipitat' ion Evaporation 2A.6 SEVERE WEATHER 2A.13 Strong Winds -- Thunderstorms Tornadoes 2A.7 DIFFUSION CLIMATOLOGY 2A.14 Surface Wir.ds, Little Rock and Fort Smith Upper Air Winds 2A.8 PRECIPITATION WIND STABILITIES 2A.24 Precipitt.i.on Winds o
2A.9 STABILITY WIND CATEGORIES 2A.28 General Smoke Plume Test and Analysis Su mn"I' of Pasquill Category Studies Analysis ofUpper Air Temperature Persistence of Wind or Calm Versus Stability Directioral Frequency, Stable Winds 2A.10 DIFFUSION MODELS 2A.42 General Two-Hour Model Twenty-Four Hour Model One-Month Model Sumnry, Site Dispersion Factors 0 Q(, 5-4-70 Supplement No. 17
~. J l j SECTION TITLE-PAGE } 2A.11 RECOMMENDATIONS 2A.47 General Early Program j-Meteorological Field Survey 1-4 l' 2A.12 REFERENC]!S 2A.50 4 2A.13 REPORTS j Early Program - November 1969 2A.54 17 4 e i J 1 i + 1- = i i i 1 r J 2A.11~ 5-4-70 Supplement No. 17 i ) 017/ d
LIST OF TABLES TABLE N0; TITLE PAGE 2A.1 Comparisons of Temperatures and Precipitation in the Arkansas 2A.10 River Valley 2A.2 Percentage Frequency of Wind Direction and Speed, Annual, Little 2A.15 Rock, Arkansas 2A.3 Percentage Frequency of Wind Direction and Speed, Annual, Fort 2A.16 Smith, Arkansas 2A.4 Duration and Occurrence of Calm and IIear-Calt Winds, Little Rock 2A.li and Fort Smith 2A.5 Duration of Calm, Little Rock AFB 2A.18 2A.6 Annual Percent Frequency of Wind Speeds at Various Hours through 2A.19 the Day, Little Rock, Arkansas 2A.7 Annual Percent Frequency of Wind Speeds at Various Hours through 2A.19 the Day, Fort Smith, Arkansas 2A.8 Percentage Frequency of Wind Direction and Speed, Six Selected 2A.21 Months, Surface, Little Rock, Arkansas 2A.9 Percentage Frequency of Wind Aloft, Direction and Speed, 850 mb, 2A.22 Six Selected Months, Little Rock, Arkansas 2A.10 Difference in Wind Direction, Ground and 850 mb Altitude, Six 2A.23 Selected Months, Little Rock, Arkansas 2A.ll Annual Frequency of Wind Direction and Speed, Light Precipitation, 2A.25 Little Rock, Arkansas 2A.12 Annual Frequency of Wind Direction and Speed, Moderate Precipitation,2A.26 Little Rock, Arkansas 2A.13 Annual Frequency of Wind Direction and Speed, Heavy Precipitatien, 2A.27 Little Rock, Arkansas OL?S J 2A.iii t
TAELE NO. TITLE PAGE 2A.14 Ten-Year Average, Monthly Calds, Little Rock and Fort Smith 2A.33 2A.15 Total Hours of Pasquill F Conditions for Each Day, Selected Days 2A.34 2A.16 Mixing Depth Versus Time, Selected Days, Little Rock, Arkansas 2A.37 2A.17 Number of Reported Hours of Persistence of Unidirectional Wind, 2A.39 or Calm, Versus Turner Number, Two Full Months 2A.18 Number of Reported Hours of Persistence of Unidirectional Wind, 2A.40 or Calm, Versus Turner Number, Nighttime Only, Eight Selected Months 2A.19 Directional Frequency of Winds, Turner Number 6 or 7, of Selected 2A.41 Months, Little Rock and Fort Smith, Arkansas 2A.20 Site Dispersion Factors, X/Q Versus Distance 2A.46 PLATES PLATE NO. TITLE ^ 2A.1 Site Location 2A.2 Wind Roses, Little Rock, Arkansas 2A.3 Wind Roses, Fort Smith, Arkansas 2A.4 Annual Frequency of Precipitation Wind Direction, Little Rock, Arkansas 2A.5 Smoke Plume, Russellville, Arkansas, July 13, 1967 2A.6 Smoke Plume Observations and Analyses Compared to Slade Resu.lts. Vertical Diffusion Versus Distance 2A.7 Directional Frequency, Stable Wir.ds, Four Selected Months Each From Little Rock and Fort Smith ) 01.@ 2A.iv
2A.1 INTRODUCTION PURPOSE OF REPORT The purpose of this report is to present the available data and the analysis thereof in regard to diffusion climatology for the vicinity of the proposed nuclear power station (Russellville, Pope County, Arkansas). A detailed investigation has been made of existing weather records from stations along the Arkansas River valley from Little Rock to Fort Smith. These data are related to the weather at the site itself, insofar as this can be done, and are used to develop diffusion models for the site, for use in estimating radiation dcsage in nomal or abnormal plant operation. Wind load design criteria are also developed. In addition, the plan for an on-site meteorological program is presented. ORGANIZATION OF THE I'IVESTIGATION The basic aim in this investigation has been to seek out significant meteorology data, assemble such data into analytical form and then interpret the data as it applies to the safety and design of the nuclear power station. The report was prepared under the directicn of Dr. Joseph 3. Knox and Dr. Todd V. Crawford, consultants, and their analyses and opinions are an integral part of the results which follow. Dr. Knox participated in the on-site investigation, l 0180 g 2A.1 m
p 2A.2 SCOPE The scope of this meteorological investigation includes the following: - A narrative climatological summary and description of general weather conditions; - Analysis of diffusion climatology based on available data and observations developed durin6 the site investigations; - Discussion of the site terrain and an analysis of possible effects of drainage wind conditions; - The development of diffusion models including,
- 1. -the two-hour model, 2.
the one-day model, and 3 the 30-day model; - Discussion of storms and tornadoes; - Discussion of design vinds; - Conclusions and recommendations; and - On-site meteorology pro 6 ram. W 01?$*- 2A.2- .O$
R 2A.3 SUE!ARY AND CONCLUSIONS The meteorology and the diffusion climatology of the Russellville site have been evaluated to provide a basis for estimating the effects of release of waste gas, estimates of exposure from a postulated accident, and design criteria for storm protection. A su= mary of the method and the results follow. The climate of the Arkansas River valley in the region of the site is primarily continental in character. The Boston Mountains, with elevations up to 2700 feet and oriented generally east-west on the north side of the valley, have an influence on the annual precipitation. The annual precipitation on the south slope is of the order of 2-4 inches greater than in the valley. Within the valley, in an east-west direction, the climatology is homogeneous. Directly to the south, hills range up to 3000 feet. Snowfall in the region is of small consequence in winter. Summer heat is observed to be frequently intensified in the river valley. TWO-HOUR MODEL From ten years of climatological data from Fort Smith and Little Rock, 8 months were identified as having the highest frequency of calm, and the highest frequency of poor diffusion conditions (Turner category 6 and 7). The lowest average wind speed during periods of Turner 6 and 7 from these eight months was 1 meter per second (mps), including the calms as 0. Thus, the 2-hour model is assumed to be 2 hours of Pasquill category F, with a unidirectional wind of 1 mps, including cal;as. For the 2-hour model, the average hourly X/Q is equal to 1.8 x 10-4 sec/m3 at the site boundary. TWEUTY-FOUR HOUR MODEL The twenty-four hour model was derived from a review of individual days in the 8 months of highest frequency of calms, described above. The 4 days selected all exhibited Turner 7 category, persistant all night long. These days were composited by hourly averaging for wind speed and vector analysis for wind direction. The results show that the model day con-sists of 5 hours of Pasquill F of 1.0 mps wind speed, all with the same wind direction. For the 24-ho dicated periods, is 10.2 x 10 y model, the sum of the X/Q, for the in-sec/m3, at the site boundary. Thus, the ( average hourly X/q for the 24-hour model is 4.3 x 10-5 sec/m3, THIRTY-DAY MODEL Based on the highest frequency of calm surface winds (10 years of data), the highest number of Turner 6 and 7 categories (2 years of average monthly data), and the highest frequency of afternoon inversion under 500 meters (2 years), it was shown that the month of October has most adverse diffusion cli=atology. To approximate the most adverse period of ~ the year, the months of August, September and October of 1963 and 1964 were selected. An analysis of Turner categories, performed on average 018?. 2A.3
i hourly data, shows that'for the greatest unidirectional unit dose, there was a Pasquill category F with an average wind speed of 2 mps, for 4 hours during' a typical day of the 30-day model. For the ty day in the 30-day model, the sum of the X/Q is equal to 3.6 x lo gicalsec/m3 after summation over the 4 hours of the typical day, at the site boundary. Thirty of such days would comprise the 30-day model. Thus, the average hourly X/Q for the 30-day model is 15 x lo-> sec/m3 The conclusions in regard to diffusion climatology of this site are: (a) that no adverse features of the diffusion climatology were found in the study, and (b) that the results of the diffusion analysis of available data provide a sound basis to use in the preliminary engineer-ing design of a nuclear power reactor. An on-site meteorology program is under way to measure wind speed, wind direction and temperature. These data will be used later to confirm initial estimates of site dispersion factors. The design criteria for the class one structures will include design loads for tornadoes. l N 01.83 J q 2A.4 y E
2A.h SITE LOCATION AND CLIMATOLOGY DATA SOURCES SITE IDCATION - DESCRIPTION The site of the proposed nuclear power station is adjacent to Dardan-elle Reservoir on the Arkansas River in vest central Arkansas. Little Rock, the state capital, is about 60 miles down-river in a south-easterly direction. Fort Smith lies vesterly about 70 miles up the Arkansas River. The town of Russellville is six miles southeast of the site. The general location is shown en Plate 2 A.1, Site Location. Physically, the site is centrally situated on a " peninsula," about two miles vide and two miles long, that extends into the Dardanelle Reser-voir. On three sides, the location is faced by reservoir water, the shortest stretch of which is approximately one mile vide in a directica southeast of the site. The normal pool elevation of the reservoir is 338 feet. Generally, the site peninsula is at an elevation of about h00 feet but with rises above 500 feet. Ground surface in the immediate vicinity of the plant site is covered by moderately thick, LO-foct tall woods. Most of thece trees, second growth, will be cleared prior to plant cperation. The site peninsula is, however, about 25% cov.ered by this second Growth. To the north of the site, the land mass gradua317 ascends to 1000 feet altitude at a distance of about 15 miles in the Boston Mountains range. The maximum height of 2700 feet is 41 miles north northwest of the site. Generally, the Arkansas River follows along the base of the Boston Mour-tains. The higher portions of the Mountains bear on the site roughly ( from the west northwest to the east northeast directions. I i To the south and vest of the site location, across the Arkansas River and Dardanelle Reservoir, another range of hills extends from a direction of due south to due vest. Directly south is Mount Hebo, elevation 1880 feet at a distance of about 3 miles. Further to the vest southwest at about 25 miles ic Ihcazine Mountain at 3042 feet altitude, the highest point in the state. To the east, and extending to the south southeast, the land area is mod-erately level, interspersed with rolling hills, frequently covered with woods. Ir2 TEOR 0 LOGICAL DATA SOURCES IN SITE VICINITY The principal sources of data, with reference to the proposed power plant, are from the Little Rock and Fort Smith weather stations, operated by the U. S. Weather Bureau. Both of these stations furnish hourly observations. Bath are in the Arkansas River valley and the power plant site is about halfway between the two. Other stations located along the Arkansas Ri-ver valley furnish daily observations of temperature extremes, rainfall, q, and miles of vind for climatological purposes. These latter data sources were examined but largely were not used in this report for reasons which 0184' vill be discussed later. A more detailed discussion of this report's 2A.5
aata cources follcws. Little Rock, Adams Field Little Rock is located on the Arkansas River near the geographic center of the state, at latitude 34 h4' n and longitude 92 14' W. Its climate is mild, with moderate temperatures and abundant, well-distributed pre-cipitation. Aanmn Field is about one mile south of the Arkanca: River. At the weather station (class A), the surface wind sensor is mounted on a 20-foot tower on grassland between two principal sirport runways. This instrument is about 1000 feet from airport buildings and other ob-structions. Daily radiosonde weather observations are taken at Adams Field. Greater Little Rock includes the City of Little Rock proper, on the south bank of the Arkansas River, North Little Rock on the north bank, incor-porated and unincorporated areas contiguous to the two in Pulocki County. The terrain to the north and west of the businesc dictrict ic hilly, rolling to the south, and gently rolling to the east. Elevations range from 222 feet at the river, to near 600 feet in the residential districts. Fort Smith, Minicipal Airport The Fort Smith class A weather station is located at the Fort Smith Air-port, which is about four miles southeast of the city and two mile south of the Arkansas River. The wind sensor is located adjacent to the airport ,) runway. Small topographic ridges, oriented northeast-southwect, ceparate the airport from the city. These hills, in conjunction with the General / topography of the river valley, are considered to have a pronounced effect on the direction of the wind under light wind conditions. A com-parison of surface wind roses from Fort Smith and Little Rock chows that the surface winds are quite different. Experienced meteorologiata practicing in the area were of the opinion the topographic effecta of Fort Smith accounted for this cited difference. Little Rock Air Force Base, J cksonville, Arkancas a This weather ctation is situated at the Air Force Bace 13 milec north north 23st of Little Rock, Adams Field. The data uced frca thic acurce aas the continuous wind velocity recordc, used for analyaic of c :hn periods. The wind sensor is located 13 feet above the cround adjacent to the airport runway. These data were not available elaewhere. Ocark, Franklin County l A climatological survey of Franklin County, was prepared by the !!eteorologist-in-Charge, Little Rock Adams Field. Ocark is about 37 miles up-river from the site in similar terrain and is quite typical of con-1. A list of references is at the end of this report. g ol m, - -b
ditions applicable to the proposed reactor site. Consequently, portiens of that survey follow. Franklin County straddles the Arkansas River in the nine county area com-prising the climatologically homogeneous west-central section of Arkansas. The data supporting this interpretation concerning homogeneity will be presented later. The topography of the county does have a noticeable effect on the weather. The southern-most ridges of the Boston Mountains cover the northern one-third of the county with hills ranging up to 1200 to 1500 feet above sea level. The elevation of the Arkansas River and surrounding sand flats is down to 340 to 400 feet. The remainder of the southern half of the county is rolling to hilly with elevations up to 500 feet. The rugged terrain in the north part of the county provides a lift to moist soup a ly airflow. Rainfall, particularly during the summer months, averages 2 to 4 inches greater in the north of the county than in the southern sections. The Arkansas River valley in this part of the state frequently inten-sifies summer heat. Conway, Morrilton, Dardanelle, Russellville, Subiaco, Ozark These towns, all located on the Arkansas River between Little Rock and Fort Smith, each have climtological weather stations reporting daily precipitation, maximum and minimum temperatures and for Russellville, evaporation pan and wind data. In addition, the Russellville Radio Station has a non-recording wind instrument. During this investigation, the climatological stations at Dardanelle and Russellville were inspected. Original weather records of wind data back to 1916 for Dardanelle and back to 1898 for Russellville were reviewed. Generally, it was found that the data from these climatological stations was not only affected by unrepresentative exposures of instrumentation but that in addition the daily climatological data was not suitable for a study of diffusion climatology. Hourly measurements of the meteorological variables at Little Rock and Fort Smith are much more suitable, and pos-sibly more accurate and representative, for the study of diffusion conditions at the site. An on-site meteorological program will permit actual on-site data to be collected for final evaluation. DISCUSSION OF WEATHER DATA A general review of the data obtained from Little Rock and Fort Smith showed enough similarity to indicate that they would adequately repre-sent the site. This generalization applies to wind speed, temperature, and precipitation. This cannot be said for wind direction, where dis-similar data is reported for reasons that have previously been cited. An investigation team visited both the Little Rock:and Fort Smith weather stations, observed the terrain and locations of the sensing equipment and discussed the local meteorology with the Meteorologists-in-Charge. g 2A.7 u
Interview with ?!eteorologist-in-Charge, Fort Smith Discussions with the Meteorologist-in-Charge at the Fort Smith Municipal Airport station were primarily about the difference in wind directions at Little Rock and Fort Smith. (See annual wind roses for Fort Smith and Little Rock in Chapter Seven.) It was the Meteorologist's opinion that the Fort Smith winds, particularly for light wind conditions during hours of maximum stability, in the wind direction at the airport was affected by the 150 foot rise in topography between the airport and the city. This produces an eddy in the vicinity of the airport and for light wind conditions results in winds of opposite direction to simul-taneous wind observations at Little Rock or elsewhere h the Arkansas River valley. This " eddy effect" is considered to be a plausible explanation, or hypothesis, because in 10 out of 12 monthly wind roses, Little Rock and Fort Smith are approximately 180 different in direction. 0 Interview with Meteorologist-in-Charge, Little Rock Discussion with the Meteorologist-in-Charge at Little Rock-Adams Field, and members of his staff, yielded the following points: -- Drainage winds at Little Rock, presumably associated with the small scale topography within the broader Arkansas Valley, are estimated to be 2-3 knots in intensity and from the southeast. This opinion } appears to be consistent with the general topography and location of j the Little Rock Airport. -- Information concerning cabs included a report that four to five hours of duration of calm wind occur reasonably frequently in the Fall. It is believed that the " calm" in this conversation meant nearly still air. -- It was confirmed that the days with greatest potential for air pol-lution were characterized by weak easterly winds in the lower atmos-phere and by low inversions. -- An opinion was expressed that the Little Rock wind measurements (par-ticularly direction) would be more applicable to the Russellville area than the records from Fort Smith. g OM ] 2A.8
i 2A.5 GENE 3AL SI"E CLL'ATOLOGY SURFACE TEMFERATURE Monthly mean and annual temperatures for the towns along the Arkansas River valley between Little Rock and Fort Saith are given in Table 2A.1 The towns are Ccmmy, Morrilton, Ihrdanelle, Russellville, Su'oiaco and Ozark. These may be located on Plate 2A.l. There in a remarkable sim-ihrity in mean temperature among the towns along this 125 mile-long reach of the Arkansas River. At Little R ock, the highest temperature reccrded during the past 77 years was 110F on August lo,1936, and the lowest was 13F belov
- ero en February 12, 1899 July has the highest monthly mean temper-ature --
819F, and January, the lowest monthly mean -- kl.8F. Tem-peratures of 90F or higher occur on an averace of 54 days during the year. Temperatures of "cero" or below have been recorded only 14 times during the past 77 years. The normal number of heating degree days per year is 2982. The greatest monthly normal is 719 degree days in Jan-uary. The Little Rock area enjoys a relatively long growing season. The average number of days between the last killing frost or freeze in the spring, and the first in the fall is 2k2. The latest recorded killing frost in the spring was April 25, 1920, and the earliest in the fall on October 22, 1893. 2 At Russellville, annual mean daily maximum temperature is 73F, minimum is 49 4F. The highest temperature of record is 113F and the lowest is -15F. Russellville has 93 annual mean number of days with temperature equal or greater than 90F and 74 days equal or less than 32F. At Fort Smith, the highest temperature ever recorded was ll3F; the lowest 15F belov tero. 1 The climatological survey for the town of Czark describes temperature in the region. The Bosten Mountains rising out of the northern sections of the county provide a slight barrier for cold air penetration frat the north in the vinter. And in the summer, the opposite effect is noticed when the Arkansas River valley traps varm air. Year around monthly tempera-tures in Franklin County aver 36ed 2 to 3 degrees higher than Arkansas counties immediately to the north in the Czark plateau sections of the state. Within the county itself, temperature variations are significant from the higher elevations of the Boston Mountains in the north to the flat central river valley sections to the south. 0188 1 2A.9 a
t i. I l 2A.1 CCEiRISOUS OF TEMPERATURES AITD PRECIPITATION IN t THE ARKANSAS RIVER VALLEYll l Little Morril-Dardan-Russell-Fort Recl: Conway ton elle ville Subiaco Ozark S::ith IEAH TEMPERATURE, 30-YEAR IIORILAL January 41 43 41 42 42 42 41 ho i February W 45 h6 46 45 44 44 1breh 52 53 51 53 53 52 51 51 April 62 53 52-03 J3 32 ja 22 -Ihy 71 '(O 70 71 To 70 39 70 June 79 79 78 79 70 79 78 79 July 82-32 82 33 02 83 C2 33 Aut.;uct '31 32 31 02 31 32 52 C2 septer.fcer 74 75 74 75 74 75 75 75 October J3 34 64 d4 54 54 54 34 .: ve..ser 50 51 51 51 51 51 50 50 i'eceaber 42 44 43 4 4 43 42 42 AICIUAL 62 63 52 63 52 d2 32 52 I2AN PRECIPITATION, 30-YEAR - HORI1AL i J.muary 5 22 4 70 4.27 4.1'( 4.04 3.22 3 41 -2..n )'. February 4 33 4.52 3 94 4.07 4.24 3 79 3 94 3 43 Ibrea 4.81 5 03 4.73 4.55 4.04 4.25 3 84 3.47 April: 4 93 5.40 k.94 4.09 5 05 4 90 4.73 4.24 thy 5 28 5 82 5 33 5 50 3 61 5 42 5.58 5 25 June: 3 61 3 95 3 90 4.2o 4.14 4 32 4.14 4 35 July 3 34 3 76 2 91 3 75 4.17 3 45 3 34 2.30 l iusust 2.82 2 93 2 95 3 32 3 79 3 11 3 10 2 92 nepteaber.3 23 3 25 3 01 29i 3 53 3 42 3 29 3.J4 odober 2.83 3 22 2 90 3 20 3 28 3 50 3 31 3.45
- ve:aber 4.12 4.39
'3 90 3 95 4.13 3 57 3 29 3 13 -December 4.09 4.45 4.01 3.39 3 47 3 53 3 04 2.82 Al'IIUAL 48.55 51.33 k3 79 40 55 49 74 Ed.33 45 14 b2.22 r l p 01.89 L 2A.10 r 4
I RECIPI"ATION Rain The mean monthly and annual precipitatien, mostly rain, data from the towns between Little Rock and Fort Smith are also shown in Table 51. The results shov rcughly similar rainfall characteristics from Little Rock to Russellville, and gradually diminishing thoreafter to Fort Smita. In all tevns, September rains are markedly similar. Inter in the fall, rain is again less in the upper river rec on near Fcrt S.aith. i The average annual precipitation for Little Rock is k8.56 inches. It occurs principally in the form of rain and is well distributed throughout the year. The vettest month is April with a normal rainfall of 516 inches, and the driest is October with a normal of 2.81 inches. The great-est monthly total ever recorded was 18.04 inches in Januar:,1937 Nc measurable precipitation was reccrded in June,1952. r.e createst amount in any twenty-four hours was 9 58 inches on April 8-9, 1913 There is an average of 106 days with measurable precipitation during the year and an average of 59 thunderstorms occur during the year. Dring the past 53 years, Little Rcek has received an average of $2/, of the possible sunshine. During the last 77 years there has been an av-erage of 136 clear days,108 partly cloudy days, and 121 cloudy days during the year. Sce least cloudy month is October and the cloudiest is January. Heavy fog occurs on an average of 10 days per year. At Fort Smith, the greatest yearly rainfall was 71.81 inches; the least 19 80 inches. The average annual rainfall was 42.2 inches. The climatological survey for Ozark, Franklin County, is considered appropriate to the Russellville site. The information which follows is extracted from this survey. Rainfall is ample for farmin6 Late spring and early summer is the vettest period. Monthly totals drop off by al-most 50 percent frcm flay to August. Annual precipitation extremes range from around 23 inches to as much as nearly 30 inches. Springtime rain is dependable. There is a 90 percent prcbability that May vill produce almost 3 inches of rain or more. General rains of a heavy and videspread nature are the result of frontal passages. This time of the year strongly contrastin5 air masses are to be found over Arkansas, par-ticularly in the northwest counties. Single storm totals of 5 inches or more are not uncommon. There is a 10 percent chance of any fall or early vinter month producing under one inch of rainfall. The summertime convective or afternoon heating variety of thunderstorms are a very unreliable source of good general rains. Even during a dry spell the state can be dominated by humid air from the Gulf of Mexico that results in videly scattered after-noon showers. Sn'cv - O.i.% It is believed that the description of occurrence of snow shown in the 9er 2A.u
1 climatological survey for Ozark, Franklin County, previously discussed, vill apply also to the proposed power plant site. This survey states that by more northern standards, snow is of small consequence. From an agricultural standpoint, snow is a poor moisture source. The average annual snowfall represents less than one inch of water content. The snowfall at the City of ozark averaged 3 7 inches per year. The record snowy year was 1921 when some sections of Franklin County totaled over 20 inches of snow. The annual mean snowfalg at Russellville for 10 years of record,1951 through 1960, is 4.1 inches. Snowfall is not of major importance in the Little Rock area. During the Inst 72 years there has been an annual average of 4 5 inches. The Greatest monthly total on record is 19.4 inches in January,1913, and the heaviest twenty-four hour fall was 13 inches on January 2,1893. Cnov does not generally remain on the ground for an extended period of time and seldom causes serious inconvenience. EVAPORATION 1 Annual evaporation from Russellville is 53 inches i Ifichest conth is July with 7.66 inches. It should be pointed out that this figure is from an evaporation pan which is kept filled to a specified depth; it does not imply that this much water is being withdrawn from the soil. Soil moisture can be rapidly depleted by evaporation durin6 the rain-free summer periods, and consequently evaporation from the soil becomes considerably less than from the evaporation pan. Russellville weather records 2 indicate, for seven years of observations, 70 mean number of days with precipitation equal or greater than 0.1 inch and 32 mean number of days with precipitation equal or creater than o.50 inch. 01.Ed- ) 24.12
2A.6 SEVEPE WEATHER STRONG WINDS -- THUI;DERSTORMS Strong winds and storms can occur along the Arkansas River valley. The mean annual number of days with thunderstorms 3 at Russellville are about
- 55. The surface wind roses are discussed in the following chapter.
However, at Fort Smith, the highest wind speed recorded in 21 yearsb was 58 mph from the north in June, 1951. In Little Rock, the highest wind speed recorded in 19 years 5 was 61 mph from the northwest in May, 1952.* TOR'IADOES A number of tornadoes have occurred in the Arkansas River valley. For 6 the 35 yesrs of record between 1916 and 1950, eleven tornadoes have been observed in Pope County and three have been observed in the vicinity of the site. About 40 tornadoes have been observed in the 46 year period of 1916 through 1961 in Franklin County and the adjoining six counties of west 1 central Arkansas. In the whole State of Arkansas, in the years 1953-1963, 189 tornadoes 7 were observed. The proposed site lies within an area of frequency of 0 50-100 tornadoes during the forty-year period of 1916-1955. In addition, the site is within an area reporting 42 tornadoes per 1-degree square 9 between 1916-1961. ASCE Paper No. 3269 gives eo mph maximum wind velocity in this area based on a probability of 100 years. This value is used for design of the Class 2 structures. 01SZ g 2A.13
2A.7 DIFFUSION CLIMATOLOGY SURFACE WINDS, L1TTLE ROCK AND FORT SMITH Wind Rose Tables 2A.2 and 2A.3 show annual percentage fregency of wind direction and speed for both Little Rock and Fort Smith It should be noted that it is the conditions prevailing at the time of the observations that are recorded. This inforn:ation is also shown on Plate Numbers 3(.2 s.nd 2A.3 In addition, the Plates show the total directional fre-quency and cah for the four seasons. In general, a fairly good correlation is seen between Little Rock and Fort Smith in total percent directional frequencies versus the various groups of wind speeds. Fort Smith has a higher percent calm and slightly lower total mean wind speed. At Little Rock, total frequency distribution and mean speed are sur-prisingly uniform in direction, nowhere varying more than a factor of 2.6 in frequency and 1.4 in mean speed. However, in Fort Smith, total frequencies vary by a factor of 9. Mean speeds, as at Little Rock, vary by a factor of 1.4. Wind directionality in Fort Smith is strongly dominated by a 45 degree sector from northeast to east northeast. This sector contains 32 3 percent of the total hourly observations. j / At Little Rock, winds of three knots or less were obtained 13 5 percent of the time. At Fort Smith, the value is 15.5 percent. Calms Table 2A.4 shows the duration and occurrence of calm and near-calm winds in Little Rock and Fort Smith, Arkansas 10 These data are based on duration in hours grouped from 1-5 hours, 6-11 hours and 12-17 hours. Data is from I? years of record con:mencing in January,1954. No calm or near-calm dt 1 tion exceeding 17 hours of observation was noted. It is observed that Fort Smith exceeds Little Rock in frequency of both calm and near-calm, regardless of the season of the year, or duration (hours) grouping. This is further supported by the analysis of Pasquill categories in Chapter Nine, wherein it was reported that by actual count, Fort Smith equaled or exceeded Little Rock in average number of calms in every month for ten years of study. In Little Rock, the duration of calm, between 1-5 hours, was observed about 220 times during the year. Fort Smith reported about 325 occur-rences of calm of duration between 1-5 hours. Including near-calm of average speed 1 knot or less, the total occurrences observed in Little Rock was 5.2 percent of the time and in Fort Smith 7.7 percent of the time. 0193
TABLE 2.A.2 AIRIUAL PERCEIITAGE FREQUDICY OF WIIID DIRECTICII AIID SPEED, LITTLE ROCK, ARKAI!SAS WIIID SPEED (Knots) Total Mean Speed: 1-3 4-6 7-10 11-16 17-21 Frec. Speed II 3 1.6 2.3 9 .1 5.2 8.1 IIIIE 3 1.8 2.7 1.1 5.9 79 I!E 5 19 2.7 1.0 6.2 7.6 EIIE 5 2.2 3.3 1.0 7.0 7.5 E 7 19 2.2 5 5.3 6.9 ESE .6 2.0 2.0 5 5.2 6.9 SE 7 2.1 19 5 5.2 6.6 SSE .6 2.2 2.3 7 .1 5.8 7.2 S 5 2.1 3.3 1.7 .2 79 8.4 SSW 5 2.1 3.4 2.1 3 8.4 8.8 SW .8 29 3.5 1.4 .1 8.7 7.6 WSW .8 3.2 25 .8 .1 7.4 6.9 W .4 1.2 1.2 5 .1 3.3 7.5 WIM 3 1.1 1.7 1.4 3 4.8 95 IM 3 13 19 1.0 .1 4.8 8.4 IIIM .2 13 2.0 9 .1 4.5 8.3 Calm 4.4 Total 8.1 30 9 38.8 16.0 1.6 100.0
7.4 IIOTE
Based on 10-years of record, Jan 1954 to Dec 1963 1 01.94 i g 2A.15 1
TABLE 2A.3 AIEUAL, PERCENTAGE FREQUENCY OF WIND DIRECTION AUD SPEED, FORT SIETH, ARKAICAS WIND SPEED (IGOTS) 'ivlab I DJi Sneed: 1-3 4-6 7-10 11-16 17-21 FREQ. SPEED N 3 1.1 1.4 7 .1 3.6 8.0 5IE .5 17 9 .4 3.6 6.4 UE 2.0 8.7 33 4 14.5 L.5 E'2 1.6 7.6 71 1.5 17.8 6.7 E 9 3.0 4.0 1.7 .1 9.6 7.( ESE 3 1.2 1.1 3 3.0 6.0 SE 5 13 1.0 3 3.1 6.L SSE .2 .8 7 3 2.0 7.0 S .4 1.3 1.3 7 .1 3.7 7.6 SSW 3 1.1 1.6 1.3 .2 h.5 91 SW .6 1.6 2.0 1.5 3 6.0 8.8 WSW .4 1.6 1.6 7 .1 4.5 7.5 W 5 2.0 25 1.0 .2 6.2 8.0 ) WK,1 .2 1.2 1.6 1.1 .2 4.3 91 IM .2 1.1 1.4 .8 .1 3.6 8.3 mu .1 7 1.2 .6 2.7 8.5 CALM 7.3 TOTAL 92 36.0 32 7 13.2 1.4 100.0 6.8 UOTE: Based on 10-years of record, Jan. 1954 to Dec. 1963 h 2A.16 cu;.c,:q
TABLE 2A.4 DURATION AliD FREQUEI;CY OF CAIl4 AIID Irrla-CAI14 UII!DS LlTILE ROCK AND FORT S4ITH, ARKAIISAS (Calm Asstmed Zero Wind Speed) Din ation (Hours) Winte" Spring Summer Autumn Annual Lit FS4 Lit FS4 Lit FS4 Lit FU:1 Lit FS1 A. Calm Conditions (Hours) 01-05 44.6 76.8 38.8 56.8 54 3 92 5 72.1 88.5 219.8 324.7 06-11 1.1 33 0.6 2.0 1.E 25 2.1 4.2 52 12.0 12-17 0.1 0.1 o.2 B. Average Speed 1 Knot or less (Hcurs) 01-05 45 3 77 2 39.4 67 5 65 2 93 0 73 4 89 2 223 3 326.9 06-11 1.2 33 0.6 2.0 15 25 2.1 4.2 5.4 12.0 12-17 0.1 0.1 0.1 0.1
0.2 IIOl'E
Eased on 10-years of record ccamencing in January,1954 Lit is Little Rock; FSM is Fort Smith 0.i.96 2A.17
12 A review of the hourly data for Little Rock for September and October, 193k, reveals 48 cecasions of calm of cnly 1 hour of persis;.:nce; 20 occasions of 2 hours; 15 of 3; 9 of h; 3 of 5; 3 of 5; 1 of 7; 2 of 8; 1 of 9; and 1 occasion of 11 uninterrupted hours. It should be noted that if the Weather Bureau hourly observations indi-cate a calm wird, that 'this is the vind condition at the time of the observation; it does not represent the vind condition for a one hour per-iod cantered at the hour of observation. An analysis was made of continuous vind speed data from LJttle Rock Air Force Base 3 to define further the duration of calm in central Arkansas. l L:ttle Rock AFB is situated 13 miles north northeast of Little Rock, Adams F! eld, Weather Station. The anemometer at the AFB conforms to Air Force Specification GQ-20. It is located 13 feet above the ground, near the runway, and is affected by aircraft operation. The manufacturer cr the ane.noccter states that the vind speed instrument is three-bladed and that the stalling speed is about 2 kt. The starting speed is about 3 kt, de-7eading somewhat on the mechanical conditica of the instrument and its m intenance history. For this analysis of duration of calm, it was mandatory that certain arbitrary rules for defining " calm" be made. This is because, during calm or near-calm viuds, there are short duration " spikes" of wind speed of a few knots. In addition the scheme bad to eliminate the passing aircraft. It was ruled that in counting the hours of persistence of calm, vind spikes of less than 5 min. duration and periods of calm less than 10 min. be ignored. The results are shown in Table 2A.5 A surprising number ) of occurrences were counted as persisting between 10 minutes and 1 hour. Thereafter, the data between the AFB and idams Field show sane correspend-ence except that,at the extremes of the record, the AFB data shcw three cases of uninterrupted calm extending up to 15 hours while Adams Field data indicate one sequence of hourly observations of calm extending be-tween twelve and seventeen uninterrupted hours. TABLE 2A.5 DURATION OF CAU4 - LI'1TLE ROCK AFB, ARKANSAS SEPIEMBER - OCTCBER, 1934 Hours of Number of Hours of Number of Persistence Times Persistence Times
- 0. 17 -1 166 7-8 3
1-2 45 8-9 5 2-3 16 9-10 3 3-4 9 10-11 2 4-5 7 11-12 2 5-6 7 12-13 2 6 -7 5 13-14 1 14-15 3 01j.W 2A.18 h
Diurnal Wind Speed The diurnal variation in vind speedd fcr Little Rock is shcun in Table SL6 and for Fort Smith is shown in Table 2A.7. The data are based on ten years of hourly observations commencing in January, 1954. The data pre-sents a typical diurnal wind speed pattern wherein strongest vinds tend to appear in the afternoons while li6hter vinds and cabs are found most frequently in the nighttime. TABLE 2A.6 ANUUAL PERCENT FREQUENCY OF WIND SPEEDS AT VARIOUS HOURS THROUGH THE DAY, LITTLE ROCK, ARKANSAS WIND SPEED (KNOTS) HOUR (LST) o 1-3 h-6 7-10 1 1-15 17 -2 1 22-33 ol 8.8 13.h 37 0 30.6 89 1.2 .1 oh 89 13 3 38.5 30.1 8.h 7 .1 07 55 10.2 35 6 35 7 12.2 7 .1 lo 7 h.2 24.1 h3 3 2h.9 2.4 3 13 .2 2.8 20 3 h3 9 28.8 3.h 5 16 .4 3.o 18.2 L8 3 27 2 27 3 19 3.o 73 37 6 41.8 93 9 22 77 12.2 35 7 33.8 96 9 .1 AVG h.h 8.1 30 9 38.8 16.0 1.5 .2 TABLE 2A.7 ANNUAL PERCENT FREQUENCY OF WIND SFEEDS AT VARICUS HOURS THROUGH THE DAY, FORT SMITH, ARKANSAS WIND SFEED (KUCTS) HO'JR (LST) o 1-3 h-6 7-lo 11-16 17 -2 1 22-33 ol 11.4 15 1 44 3 22 5 6.1 .5 .1 ok 11.4 13 0 hh.3 24.7 6.1 .h .1 o7 8.2 94 L2.0 32.8 6.9 .6 lo 2.4 h.8 28.6 kl.9 19 8 2.4 .1 13 15 37 23.o 41.4 26.5 36 3 16 1.1 35 23.o 4h.2 25 7 2.2 3 19 94 11.0 41 3 29 2 85 5 .1
- 22..
13 5 13 5 42.1 24.4 55 7 .2 AVG (,73 92 36.0 32 7 13 2 1.k .2 0198 2A.19
k V ainage Wind fhe Arkansas River valley, from Little Rock to Fort Smith, obtains its mini-mum width in the vicinity of the proposed plant site. This width is sharply defined with Mount Nebo on the south and the Boston Mountains on the north. Under stable easterly flow conditions there may be expected to be some increase in the ventilation factor at the site, of the order of say 20%; however, there is to date no meteorologic data to support or document this possibility. Ground sloping upward to the northeast of the site may introduce weak micro-scale drainage winds. This will be studied during the on-site program. UPPER AIR WINDS A comparison was made between wind conditions at the surface and at an altitude of 850 mb (roughly 1500 meters above ground surface). The days surveyed were in the months of August, September and October for the years 1964 and 1965. Although general surface wind rose data are given in the first paragraphs of this section, a tabulation of the surface wind for the same time period, is necessary for valid comparison to the winds aloft data. Table 2A.8 shows the surface wind characteristics. Table No. 2AS shows the comparable wind characteristics at an altitude of 850 millibars. The difference in wind direction between surface and aloft is displayed in Table No. 2A.10. Referring to Table No. 2A.3, it appears evident that for the time period ) s adied the surface wind directional frequency favors the quadrant from between east and south. This strong preference was not evident in the 10-year general seasonal or annual data for Little Rock previously shown. The mean wind speeds from all directions appear similar. The data in Table No. 2A.9 reveals a more uniform wind direction frequency aloft. Speer' is markedly increased, with an over-all mean of 21.1 knots. It may be interesting to observe that highest aloft speed detected was 69 knots from the ENE. This unusual observation accounts for the inordi-nately high mean speed calculated from that sector. In Table No. 2A.10,the difference is shown between wind direction on the ground and aloft. The observations are referenced to the ground wind direction. This table shows that, for the time period studied, northerly and westerly winds tend to exhibit similar directions for both ground and aloft, whereas easterly and southerly winds exhibit larger direction differences. In over 50% of all observations, the 850 mb wind varied more than 45 degrees from ground direction. These large changes in wind direction and speed with height would cause greater diffusion rates than those predicted using a unidirectional surface wind; hence the predictions to follow should be conservative. b3.$ g 2A.20
TABLE 170. 2A.8 PERCEiTAGE FPIQUDICY OF SUPJACE WI'ID DIFICTICII AIID SPEED, SIX SELECTED !<0liTF2, LITTLE ROCK, AR1%;SAS AUGUST-SEPTEGER-CCTOBER, 1964-1965, WIIID SPEED, K:iOTS 1700 Local Standard Time TOTAL IMI 1-3 4-6 7-10 FPIQ. SPEED II 2.7 2.2 0.5 5.4 3.8 III'E 2.2 1.6 1.1 4.9 L.h 12 1.6 2.2 05 4.3 b.3 EI2 2.7 2.2 4.9 33 E 4.9 6.5 11.4 3.7 ESE 93 5.4 14.7 3.1 SE 71 4.3 11.4 3.1 SSE 2.2 2.2 0.5 4.9 4.0 S 3.3 49 0.5 8.7 4.1 SSW l.6 2.7 4.3 39 SW 1.6 4.9 6.5 4.3 WSW 2.2 3.8 6.0 3.9 'd 1.1 1.1 2.2 3.5 WIT 4 1.1 05 1.6 2.9 174 05 2.7 05 37 4.9 IIIT4 1.1 2.2 3.2 4.1 CALM 1.6 TOTAL 45 2 49 4 3.6 3.7 0200 g e 2A.21
TAELE No. 2A.9 PERCE1TAGE FPIQUEICY OF WEID ALOPI DIFICTIoII AIID SPEED 850 mb, SIX SELECTED MoliTIG, LITTLE ROCK APJEISAS AUGUST-SEPTEIM-OCTOBER, 1964-1965, WHiD SPEED, knots 1715 Local Standard Time Total Mean 1-3 4-6 7-10 n-16 17-21 22-27 28 plus Freq. Speed II o.5 0.5 3.8 2.2 1.1 0.5 0.6 92 13.1 IIIIE o.6 1.1 2.7 2.2 05 1.1 8.2 11.7 lie 0.5 27 2.2 5.4 99 EI:E o.5 1.1 1.1 o.6 3.3 19 9 E o.6 2.2 1.6 0.5 4.9 6.7 ESE 1.1 27 3.8 n.1 SE o.5 0.5 1.1 1.1 0.6 0.6 4.4 13.9 SSE 0.5 1.1 2.7 05 4.8 12.1 S 1.6 1.7 3.3 2.2 1.6 10.4 14.2 Ssw 1.1 3.3 05 1.1 6.0 15.0 SW 0.6 0.6 3.8 05 1.6 7.1 15.4 WSW 2.7 27 2.2 05 8.1 10.1 W 1.1 2.2 1.1 05 0.6 1.1 6.6 14.6 ww o.6 1.1 1.7 05 05 3.8 11.8 m 1.1 1.6 1.1 1.1 05 5.4 17.3 12TJ 0.6 1.6 17 2.2 0.6 6.7 14.3 CALM - 1.6 TOTAL 3.8 13.6 26.8 32.2 91 8.8 4.4 21.1 g 0203. 24.22 m
TABLE NO. 2A.10 DirnRE' ICE ET WIIID DIRECTICH, GROUND AID 850 mb ALTITUDE, LITTLE ROCK, ARKAIISAS Ground IIO OF OBSERVATICI;S, AUGLE BETdEEN GROUITD AIID 850 rio 'sind Avas Direction 0-1k0 15 -29 30 hh 45 -59 0 60 -740 0 0 75 -1800 CASES U 3 1 2 1 1 2 10 UI!E 2 2 4 1 9 I:E 4 1 1 2 8 EE 1 2 2 1 3 9 E 2 1 4 3 5 6 21 ESE 1 8 2 1 15 27 SE 2 4 5 1 10 22 SSE 1 2 2 2 2 9 S 5 1 5 2 1 2 16 SSW 1 1 1 1 4 8 SW 3 2 1 2 h 12 WSW l 3 1 3 10 W 1 1 1 1 4 WIF4 1 2 3 IT4 4 1 1 1 7 11174 1 1 1 3 6 T TAL 28 13 36 25 20 59 181 HOTE: BASED Oli OI!CE-DAILY 03SERVATICIIS AT HOUR 1715 LSI DURE!G PERIODS AUGUST TO C'CTOBER,1964 and 1965 Ground Level Calm on THREE DAYS. 0202 h 2A.23
f r 2A.8 PPICIPITATION WIIO STABILITIES PPICIPITATION WINDS The annual precipitation wind rose 10 for Little Rock, Arkansas, is shown in Tables 2AJ1(light precipitation),2AJ.2(moderate precipitation), and a.B(heavyprecipitation). Light precipitation, other than drizzle, is from trace to 0.10 inch per hour; moderate is defined by the U. S. Weather Eureau as 0.11 inches to 0.30 inches per hour; heavy is more than 0.30 inches per hour. This data is also shown on Plate 2A.4. The data shows that for Little Rock, most light precipitation is from the quadrant of north to east northeast with winds of 4 to 12 mph speed. During moderate precipitation, much the same conditions occur as during light precipitation. During heavy precipitation, most of the observations are with winds from southwest, to the northwest with velocities about equally shared between the 4-12 mph and the 13-24 mph categories. Seasonal breakdown of the above information reveals that light and moderate precipitation occur most frequently in the winter but that heavy precipitation occurs most frequently in the springtime. ] 2A.24
O TABLE 2A.11 AI27UAL FREQUEI!CY OF WIIiD DIRECTION AIID SPEED, LIGHT PRECIPITATICIT, LITTLE EOCK, ARKAI;SAS WIUD SPEED (!EH) TOIAL SUM OF SPEED l-3 h-12 13-24 25-31 32 L6 023 SPEED I' 16 370 140 4 530 5487 17TE 24 444 166 1 633 6459 ITE 31 477 148 656 6432 EI:E 26 492 144 662 6394 E 30 372 63 1 466 4113 ESE 15 284 51 1 351 3070 SE 34 302 62 2 400 3535 GSE 14 264 82 2 362 3566 3 11 250 114 2 377 4071 SSW 17 214 88 2 1 322 3354 GW 22 187 38 1 248 2166 WSW 11 146 42 199 1909 W 12 129 36 177 1660 WIT 4 13 186 101 2 302 3236 IM 14 209 95 2 1 321 3386 inn 16 281 119 416 4295 CALM 97 TOTAL 306 4607 1489 20 2 6521 63133 02.04 2A.25
TABLE 2A.12 s MU!UAL FREQUENCY OF WHID DIRECTION AHD SPEED, 'NODEPATE PRECIPITATION, LITTLE ROCK, ARKANSAS WIND SPEED (MPH) 0F . SPm 1-3 4-12 13-24 25-31 OBS. SPEED 1 40 424 I IE 1 22 1 41 493 II 4 29 7 40 367 EII 29 u kl 430 E 17-2 19 176 ESE 2 13 6 2 249 SE 16 6 222 SSE. 1 g 6 1 16 194 S 1' lo g 15 143 SSW g 2 107 SW 12 3 15 149 WSW 1 7 g 26 '<l 17 3 20. 213 s.) WIN 1 13 9 1 24 294 IM 1 19 n 31 354 HIM 2 .17 g 27 271 ' CALM 3 TOTAL' 15-263 n4 3 398 4212 l I i*i-020d g t g' ^ 2A.26
TAELE 2A.13 ANIiUAL FREQUEICY OF WIID DIRECTICII AND SFEZD, HEAVY PRECIPIIATICII, LITTLE ROCK, AVAI!SAS WIIID SPEED (MPH) TOIAL SUM OF SPEED 1-3 h-12 13-24 25-31 32 h6 OBS. SPEED II 6 1 7 66 I:ITE 5 2 7 76 IE 3 3 27 EE 2 3 5 67 E 3 1 4 44 ESE 1 1 1 3 55 SE 5 5 47 SSE 2 3 5 61 S 1 2 3 47 STd 3 2 5 55 SW 5 3 1 9 124 WS'l 3 3 3 9 150 W 3 5 2 10 186 WITd 5 7 12 190 Ird 6 6 12 158 IEM 4 2 6 77 CALM TOIAL 57 41 5 2 105 1h30 l g O'J.06 2A.27 i )
2A.9 STABILITY WL7D CATEGORIES GENERAL Overthe3ast30-@ years,manyinvestigatorshaveworked,experimenta1p and theoretieg1ly, on the 1 and Pasquill > for review) problem of atmospheric diffusion (see Sutton l The theoretical solution most applicable here is the solution for a continuous point source at the ground surface in a unidirectional wind field of constant speed. This is Z 2- ,Y+Z.. 7= Q l ex p - g-2.
- 2, (1) g g
where '% = concentration, units /m3 CL = release rate, units /sec 64f = crosswind standard deviation, m 67 = vertical standard deviation, m 3 = mean wind speed, m/see In Fickian diffusion, CL can be identified with 2Kt where K is a con-stant diffusivity and t is time. If the release is above the ground ) surface and one is only concerned about ground level concentrations, then Equation (1) should be multiplied by 2 and h (height of release) should replace a before squaring. This would reduce the ground level concentration within a distance of a few stack heights from the point but has little effect beyond the point downwind where Q geleage ph It should be noted that such a point source solution is applicable only if the time of release is 1c,ng ccanpared to the time of arrival at some point downwind. In addition, only the concentration at the centerline of the cloud will be considered in this report; this exponential term in Equation (1) will be unity. In Nuclear Safety 16, the plume axis prediction of Equation (1), assuming a reflection boundary condition, is modified to, l -(Tr g Oy~ + C A)A4 Q (2) where C = an experimentally determined constant (range h to 2) A = cross-sectional area of building complex from which 2 source is being emitted, m, 1 l hv l N a 2A.26 L
This modification to Equation (1) accounts for the increased dillution in the wake of a building. The constant C has been detemined experi-l0 mentany and more recently by Dickson17 at the National Reactor Test Center and has been found to lie between } and 2. A variety of methods have been used to predict O. and 0} as a function f of dist Pasquilgle downwind but the basically empirical scheme proposed by will be used here. Pasquill proposed six weather classifi-cation categories ranging from unstable conditions with light winds through neutral condition and wind to stable conditions and light winds. The classification into 6 categories (A to F) depends on surface wind speed, insolation in daytime and cloud cover at night. i In these classifications, horizontal spreading was represented by an included angle for the different categories. Vertical standard devia-tion was given as a function of. distance downwind for the different categories. The experimental diffusion data that were used in Pasquill's correlation were reasonably complete from categories 5 through D. How-ever, for categories A, E and F and distances greater than one kilometer, the chart is essentially extrapolations. Turner 9 1 provided a quantitative method for categorizing the diffusion characteristic of the day. His method uses the regular Weather Bureau surface hourly observations. Near the ground, stability depends pri-marily on net radiation and wind speed. During daytime hours, with clear skies, insohtion (incoming radiation) depends on solar altitude, which is a function of time of day, time of year and latitude. Clouds inhibit both insolation and radiation. In Turner's system, insohtion is estimated by sohr altitude and modified for the effect of cloud cover and ceiling' height. The Turner number depends on wind speed and net radiation index. The stability categories as detemined by the method of Turner are related to the Pasquill categories (A to F) as follows: Atmospheric Pasquill Turner Condition Letter Humber Extremely Unstable A 1 Unstable B 2 - Slightly-Unstable c 3 Neutral D 1+ Slightly Stable E 5 Stable F 6 Extremely Stable 7 For convenience, Turner Nos. 6 and 7 are both called Pasgill Letter F for purposes of estimating diffusivity. Recently, Slade has su=marized much experimental data on continuous point source plume diffusion. The i smmary includes the data used by Pasquill but also makes use of much more recent data. Curves of 6tg, and 6~ yare presented as a function of downwind distance and different stability categories. A method is given' for estimating the stability categories from a continuous record of wind direction and rehted to Pasquill categories. Ogg g g 2A.29 l _J
r The vertical mixing value, Oh, developed from experimentally-cbtained data, applies where no other restraint to mixing exists. In a practical situation, hcwever, the mixing depth limit is reached when the base of the first inversion on top of the mixed layer is reached by the diffusing plume. This imposes an additional restraint on 6y', for daytime stability categories, which may be sig-nificant as downwind distance increases. By definition, categories E and F have surfge-based inversions included in the empirically-detemined 6~ 's. y Holsworth evaluated mean radiosonde observations and nomal maximum surface temperature and used the assumption of a dry adiabatic lapse rate to estimate monthly mean maximum m4ving depths (leID's). This analysis was done for 1+5 stations in the United States, including Little Rock, Arkansas. In calculating the O'y for the one-month model condition, the Holsworth IGID for the month of October was used as an additional mixing restraint. Indeed, the ?GD was fur-ther reduced to one-half its value for the morning hours to and including 1200 IET to aHow for the fact that the depth of the adiabatic layer increases from dawn to its ISD in mid-afternoon. For the 21.-hour model, the composite radiosonde and surface temperature data were used for the actual days studied to establish the physical mixing depth limit for each hour of the day. In the analysis that follows, time dist-ributions of the quantity X/Q win be considered for certain classes of days or months. It is pertinent to point out that if the value of Q is set equal to a unit release rate, then X/Q physically represents the capability of the atmosphere to dilute the material from a surface The following methodwasusedtodeterminevaluesofX/Q,sec/mptsource. -- For the days or months selected for analysis, the wind direction, speed, sky N cover and ceiling were obtained for each hour from the Local Climatological
- Datal2, j
-- The daytime insolat on values and/or the net radiation indices were estab-liched for eae . ur and from this and the wind speed the corresponding Turner numb was determined. -- Turner Numbers were converted to Pasquill categories. appropriate U4f'and 7 values for the distance of interest vere ~ -- The 7 derived from th summaries provided by Slade20, gy was then compared to the IG!D; if O[3 lGID, then Op is set equal to the led; if ?GID E Cp, then noalterationismadeinthevalueofOp. -- Compute X/Q, using Equation (2) for each hour and distance of interest. SMOKE PLUME OBSERVATIONS AND ANALYSES The Observation of Smoke Plumes During Site Visitation On July 12-13, 1967, the meteorological investigative team visited the reactor site for purposes of familiarisation with the environs, for interviews, and for completion of data acquisition. During this trip observations and docu-mentary photography were conducted of stack smoke plumes in the Arkansas River valley. Plumes were observed and photographed with a line of sight nor=al to the plume on two different days at Russellville, and for one day at Oppello. 2A.30 N r
Cn the afternoon of July 12th, the weather was broken middle clouds with 12,000 ft ceiling and scattered lover clouds. A cold front (quasi-stationary or moving very slculy) was located south and east of Russ-sellville. Wind speed and direction recorded at Little Rock and Fcrt Smith for the afternoon of July 12 vere as follows: Timej Little Fort LST Rock Smith 1200 N 14 SW 9 1300 SW 9 W8 1400 SW 12 W9 1500 W 13 W8 1600 USW 12 IiW 5 1700 W 9 W5 1300 SW 9 SW 7 On July 13th, the slowly moving cold front had passed to the east of Little Rock at 0100 LST, so that broken clouds were observed there at 0900 LST. However cbservaticns at the site and at Fort Smith indicated less than 1/10 high clcud cover. Winds during the observations of the smoke plume were as follows:
- Hour, Little Russellville Fort LCT Rcek Wind Temp Smith 0900 W 13 N3 72 N 9 1000 W 10 Ice 8 75 N 5 1100 N 9 IIUE 5 78 W 4 1200 tie 9 IEIE 3 80 N 9 1300 W 9 W 14 1400 W 12 N 14 Method: On July 12 the kiln plume was observed at Russellville for a period of abcut thirty minutes, during which period the plume was pho-tographed from a line of viev normal to the plu e. Plume photogaphs were taken at the time when the plume was judged to be in average configur-ation for the subperiod just observed.
Cn July 13, observations and the photogaphy were made from the air, with the sa.e requirements that pho-tographs must be taken alen6 lines of si ht as normal to the plume as C possible. The necessary dimensions of stacks and buildings were obtained to permit a quantitative analysis of photographs. Aerial observations of the plumes from a paper mill stack at Oppello, Arkansas, and the afore-mentioned kiln stack at Russellville were made on the second day. From the meteorological data given, the appropriate Pasquill cater.;ories were determined correspondin6 to each plume photograph. The values of % were determined from the plume vertical spread by assuming the spread equal to 40f. The values opwere then compared to those summarized in Figure o of Slade's paper A photograph of the Russellville kiln smoke plume is shown on Plate 2A.5 Values forpbtained during the observation are shown on the Slade dia-Gram, Plate 2A.6. 0*910 g 2A.31 ~
Observational results are as follows: - The plume observation of 12 July at Russellville,1600 LDT. Measure-ments of the vertical plume spread indicate an@of 3 meters at a distance of 20 meters. Diffusion conditions were estimated as Pas-quill C or D vith the vind east southeast at 3 knoto. - Plume observation of 13 July at Oppello, 0915 LIff. Wind was from the northwest at 8 to 10 knots. Diffusion category was Pasquill B or C. Reduction of the photographic data and removing the vertical meandering of the plume gives the following estimates of Of. Distance, m 100 200 300 400 500 @m 11 19 22 30 32 - Plume observations 13 July at Russellville, 0940 LDT. Cloud cover was less than 1/10, vind was estimated to be north, 6 to 8 knots. Diffusion category was Pasquill B to C. The reduction of the pho-tographic evidence assuming plume vertical spread equal to k Cp, - gives the following data. Distance, m 100 200 300 CJ7.,m 6 73 32 Discussion of the plume analysis is referenced to Plate a.6. Slade's curves and data apply to about thirty minute releases. The observa-tions of the three plumes represent typical conditions for at most ten ) minutes. Aircraft photographs of plumes were typical for probably a shorter length of time. Ncnetheless, the general agreement of the in-ferred Ofvalues with= Slade 's data is encouraging. It should be noted thatCJ" data for any one plume tends to shift to higher Pasquill cate-cories as distance increases. This is believed due to the loss of opacity of the smoke as distance increases and it is in part due to less than ideal contrast between the plume and background. In general, the 100 meter value of Cptermined by the plumes fits the su= mary of as a function of Pasquill category given by Slade. Admittedly, the, um-ber of plumes observed and analyzed during the site visitation is s=all; however, no evidence is found that the diffusion of plumes in the central Arkansas valley is in any way incensistent with the dispersion su=ary of Slade. SUWARY OF PASQUILL CATEGORY STUDIES In order to begin an identification of adverse periods of diffusion conditions, the Local Climatological Data with hourly Supplements, for ten years of record from 1956 to 1965 for both Little Rock and Fort Smith, vere analyzed. This was with regard to number of hourly reports of calm surfacevinds/ month. The average number of hourly re' ported calms as a function of month are shown in Table 2A3 for the ten year perica studied. It is noted that both weather stations reported October as the month of. highest average hours of calms: 64 hours at Little Rock and 73 hours at Fort Smith. This is an average of about 10% of the October hours. s A.32 g,311
i TABLE 2A.14 TEN-YEAR AIiHUAL AVEP1ErE, MOITIHLY CAIES, LITTIE ROCK AND FORT SMITH Little Fort Little Fort Month Rock Smith Month Rcck Smith Jan 33 59 Jul 48 60 Feb 20 47 Aug 54 59 Mar 17 37 SeP 61 61 Apr 21 39 Oct 64 73 May 33 52 Nov 47 50 Jun 38 58 Dec 39 57 From this analysis of hourly reported cabs, certain months were iden-tified as containing a Inrce number of cabs. These are listed belev. Little Rock Aug. 1954 109 cabs Little Rock Sep. 1954 143 calms Little Rocle-Oct. 1953 107 ca bs Little Rock Nov. 1964 113 calms Fcrt Smith Jul. 1951 137 calms Fort Smith Aug. 1960 112 calms Fort Smith Sep. 1960 107 calms Fort Smith Oct. 1950 104 calms Curiously, the single month of highest number of reported calms in Little Rock (September, 1954) or Fort Smith (July, 1961) was not the month of highest average number of reported calms (October). Likewise, when Little Rock was experiencing a record number of reported hourly cal =s in August, September and November of 1954, the reported number of hourly calms at Fort Smith were below average. Having identified the eight "vorst" months, on the basis of reported hour-ly calms, in the ten year period, the next phase of the study was con-cerned with determining the Itsquill stability categories as a function of time for these months. The method used was as previously described. Generally, only the nighttime hours were analyzed as to stability cate-gory since, by and large, the poorest diffusion conditions prevail dur-ing the nocturnal period. Ecwever, out of the 245 days categorized, 71
- days were categorized for all 24 hours, to obtain some description of the diur-nal distribution of stability cate6eries. The results of this analysis are shown in Table 2A.%, which lists total hours of Pasquill F conditions for each day of the selected months. The Table also lists the monthly average wind velocity ( calms = 0), during the Pasquill F conditions.
Table 2A5 shows again that October is the month of poorest diffusion when expressed in terms of highest frequency of.F categories per month. The table also shows that the lowest monthly average vind speed, during the
- Pasquill F conditions, is 1.0 meter per second. The average vind speed duringsPasquill F for the entire eight months is 1.4 meters per second.
OnA m M 2A.33 i'
TABLE 2A.15 TOTAL HOURS OF PASQ,UILL F COIDITION FOR EACH DAY, SELECTED MONTHS LITTLE ROCK FORT SMITH 1964 1964 1963 1964 1961 1960 1960 1960 DAY AUG. SEPT. OCT. NOV. JULY AUG. SEPT. OCT. 1 4 11. 13 13 9 n n 3 '2 8 n 13 9 7 11 11 7 3 n 11 12 12 9 lo n 9 L 9 11 12 13 9 7 11 3 5 8 n 13 lo 9 11 n 6 6 11 11 13 5 6 lo 8 11 7 9 n 13 1 4 n n 6 8 8 9 13 9 4 4 n 6 9 11 11 13 n 7 4 7 12 10 lo la lo lo 7 5 7 12 11 7 6 10 1 5 7 10 12 12 5 1 12 5 7 9 10 9 13 9 5 12 12 7 11 11 9 lb 4 n n 6 1 8 n 6 15 o lo 10 4 1 lo 5 8 16 4 5 11 5 o 8 10 12 17 9 /1 n 1 6 o n 13 18 7 9 lo o 9 6 n 1 19 9 11 13. o 9 9 n 2 20-9 8 13 4 8 7-6 13 21 1 10. 13 6 5 5 4 13 22 2 n 13 13 3 n 2 13 23 4 3 13 12 5 11 6 13 24 7 7 12 'n 8 o 2 13 25 6 5 13 5 9 7 o 6 26 4 7
- 13 o
i 6 o o 27 8 1 .9 o 7 6 5 n 08 8 o 4 o 9 to n 7 29 8 5 lo lo 7 11 n o 30 7 11 9. 6 9 11 9 o 31-9 7 9 11 5 T MAL 216 234 354 194 202 248 245 241 if,mps 1 3 - 1.1 15 -1.8 1.0 1.4 13 1.4 NO2E: Cal::: assumed zero wind speed. 0Z.0 9 g 2A.34
) Hence, from this analysis of 10 years of LCD inforration, cn the basis of monthly frequency of calms, the fall months, on the average, have been identified as having the most adverse diffusion conditions. Eight indi-vidual months of poorest diffusion conditions have also been identified. The analysis of Pasquill category during these months indicated the lev-est monthly average vind is 1.0 mps during Pasquill F for this sample. This vind speed value vill be used as input for the two-hour diffusion model. ANALYSIS OF UFFER AIR TEMPERATUIE In order to obtain a mcre complete description of diffusion conditions, radiosonde data for Little Rock - the only Arkansas station reportin6 and the closest reporting station to the power plant site - vere stud-1ed. '@AU 32A charts at 1800 Isr, for each day of August, September and October for 1934 and 1965 were examined. As has been pointed out, Oct-ober is the " worst" month of the year as far as diffusion goes, so those 3 months are biased toward poor diffusion conditions. Radiosondes for 184 days vere examined. With regard to inversions, the s following information was secured: - Ho daytime inver sions ------------- ---------- - --- ------ ---- - 59 days - Daytime inversion base higher altitude than 850 mb ---------- 57 days - Daytime inversion base lower altitude than 850 mb ----------- 58 days Of the 69 days showing no daytime inversions, 33 vere in Augusts, 22 in Septembers and 14 in Octobers. Of the 58 days when the daytime inversion base vt.s at a lower altitude than 850 millibars (mb), eleven days showed ground-base inversions. These eleven days exhibiting ground-base temperature inversions at 1800 were then examined in Greater detail, in re6ard to mixing depth. The days of interest were: 1964 1955 September 26 August 21 October 18 August 22 October 22 October 2 October 24 October 3 October 17 October 24 October 28 02.i.de 2A.35 S L._
'"emperature was plotted versus altitude for both the hcur 0600 and 1800 cr. 'CAU 31A charts fron the ground surface up to 500 mb. This corresponds rcutl, to an altitude of 5750 meters above sea level. Hourly surface temperatures, for the daylight hours, were plotted and extrapolated dry adiabatically upward to an intersection with the radiosonde data to de-t,crmine 'the depth of the mixed layer. In this analysis,the height of the mixing layer is defined as follows: - The height or depth of the mixin6 layer, H, is the vertical distance from the surface of the earth to the base of a non-surface-based in-version er the height of the intersection of a dry adiabat through the surface temperature and the radiosonde data. - In the early mornin6 hours, and at or near sunset, stable air can ex-tend through some depth to the surface of the ground. In the case of fht grrain, H is then estimated as the depth of the planetary boundary layer , and can be estimated to be of the order of 50 to 100 meters. In the case of stable air extending to the surface during nocturnal hours and for uneven terrain, it has been suggested by Gifford22 that the height of the planetary boundary layer be estimated as the height of the surrounding hills. 3 om the Russellville site, the fine-scale topography has a height of about 50 meters. Hence, during periods of stable air overlying the site, at near sunset and to near sunrise, the mixing layer depth is about 50 to 100 meters. The results of the analysis are shown in Table 2A16.0f the eleven cases examined, two (October 2 and 3,1965) had multiple inversion structures overlyin6 the earth's surface for the full twenty-four hours. These two days, since they were sequential, constitute a forty-eight hour period dur-ing which there was a minimum extent of vertical mixing; the limit of vertical mixing. of course, varied diurnally. The other nine cases examined showed periods during which the inversion was broken by daytime heating. The duration of a deep mixing layer ap-pears to be longer in the month of August than in October. In Table 2A.16, if the mixing depth is shown in parenthesis, e. g. (50), this value is determined by the depth of the planetary boundary layer. If the mixing depth is recorded on the table without a parenthesis, then it was determined by the distance to the nearest inversion during daytime heating, or by adiabatic extrapolation of the surface temperature. PERSISTENCE OF WIUD OR CAIM VERSUS STABILITY An analysis was made of vind (or calm) direction persistence as compared to Turner Number stability categories. All days of the months of October, 1933 and September,19A vere examined. These months were seleted since, firstly, they belong to the four months of highest number of calms for Little Rock for the 10-years,1956-1955 and, secondly, of those four months, they exhibit the greatest number of Pasquill F category hours. J 2A.36 Oo:w. O
TABLE 2A.16 IC QiG DEPTil Vs TD2, SELECTED DAY 3 LITTLE ROCK, ARKAli3AS LETERS 1964 1965 Sept october August october HOUR 26 18 22 24 21 22 2 3 17 24 28 0515 (50) (50) (50) (50) (50) (50) (50) (50) (50) 60 (50) 0600 (50) (50) (50) (50) (50) (50) (50) (50) (50) 60 (50) 0700 88 (50) (50) (50) 0800 88 90 160 (50) 0900 210 920 3CO 100 IGD 240 llo (50) 230 llo llo 1000 13D led ICD 350 1100 L29 F2e IGD 580 1200 IGO 180 ICD 820 Ice les lolo 910 too 1200 Ice 1300 L2e 90 Iso 10 0 1400 too 90 tco tem 1500 I00 90 52 0 14 0 b20 L2e 950 o Ice 1320 GD 1600 Iso (50) !co !co 1 1700 (50) (50) (50) (50) 1715 (50) (50) (50) (50) (50) (50) (50) (50) (50) (50) (50) (50) indicates value determined by depth of the planetary boundary layer indicates mean L2e is mean maxir:um mixing depth l 970 meters y indicates hour not ana4 zed 02.i.6 t' 2A.37
Using the methcd previously described the oppropriate Turner Number was assigned to each hour of the day for the two months of study. These 1L64 hours were then categorized according to consecutive hours of per-sistence, from a single 22.5 degree sector, of wind or calm. The results, Table 2A17 indicate that regardless of 1) stability, 2) wind or 3) calm, the persistence of only one hour duration occurs 82.2 percent of the total. On three different occasions during these two " bad" months, cabs with Turner 7 stability persisted for eight consecutive hours. Eight months of nighttbe-only data were also inspected to compare the persistence of wind (or cab) with Turner Number. The nighttime-only data are significant since the diffusive ability of the atmosphere is weaker at night than in the daytime. The months selected are the same as those described previously. The results of the nighttime comparisons are shown in Table 2A19. These data indicate that during the nighttime a 1-hour persistence of uni-directional wind, or calm, regardless of Turner Humber, occurred 75.8 percent of the time. Of these, most (51 percent of all cases) occurred, as expected, during Turner 7 or Turner 6 conditions. For the period studied, one case of persistence of Turner No. 7 cah for ten hours was recorded. DIRECTIONAL FREQUENCY, STABLE WINDS An analysis was made to determine the frequency of Turner No. 6 and 7 versus wind direction, or ca b. For this analysis, all of the nighttime hours for the eight months described previously, were selected. / The results of the comparison are shown in Table 2A.19and on plate 2A.7 The wind directional difference between the weather station at Little Rock and Fort Smith is observed in these results. It is noted that Turner Number 6 or 7 occurred in about 24 percent of the nighttime ob-servations in Little Rock and about 32 percent in Fort Smith. These percentages are probably high as a result of the method of choosing the months for analysis. ,w gML d 2A.38
TABLE 2As17 IIUMBER OF HOURS OF PEFSISTDiCE OF UITDIRECTICIIAL WIND OR CALM, VEPSUS TURIIER ITUMBER, TWO FULL MOIEHS Hours of Per-IEER OF OBSERVATICIIS OF IURIER IIUMBER sictence 74 7C 6W 6C SW 5C 4W 4C 3W 3C 2'I 2C IW 1C E 1 95 31 182 16 60 0 165 2 169 15 149 7 0 2 82.2 2 12 20 13 5 6 31 2 21 3 9 2 11.6 3 2 9 6 h 2 12 3 1 35 4 6 5 4 1 1.h 5 1 2 1 1 1 0.5 6 1 1 1 1 0.4 7 1 0.1 8 3 03 IIOTE: DIRECTICN IS WITHIH 22 5 DEGREE SECTOR. DATA IS FOR LITTLE ROCK, ARKANSAS, FOR OCTOBER, 1963 and SEPTDGER,1964, SELECTED AS TWO MOICHS OF MOST ADVERSE DIFFUSION C0HDITIONS 74 IMIS TUFlIER NUIER 7 WITH WIUD 7C MEADS TUFlIER IiUMRER 7 WITH CADI g O'd 1.8 2A.39
TABLE 2A.18 IG!BER OF REPORTED HOURS OF PERSISTEIICE OF UUIDIRECTIONAL UIUD OR CAU.!, VERSUS TURNER IIUI3ER, HIGHTIIME OITLY, EIGHT SEIECTED MOUTHS 3 8 Number of Observations of Turner Number sistence 7W 7C 67 6C SW SC kW LC 6 1 332 120 575 69 270-1 208 15 75.5 2 31 56 63 24 47 97 5 15 4 3 3 34 36 7 10 10 2 49 4 1 16 16 1 1 14 23 5 9 2 3 1 3 1 09 6 4 3 1 2 05 7 1 40.1 8 2 1 0.1 9 10 1 (0.1 NOTE: Direction is within 22 5 degree sector Data is for Nighttime Only for Little Rock For October,1953; August, September, October,1954; And Fort Smith -- July,1951; August, September, October,1950; Selected as InrQcularly adverse months, on basis of Number of Calms 7W means Turner Humber 7 with Wind 7C means Turner Number 7 with Calm g OO}.b 2A.40
TABLE 2A.19 DIRECTI0 ITAL FREQUENCY OF WIITDS FCR TURIER IIUMBERS 6 m 7 FOR SELECTED MONTHS Number of Observations LITTLE ROCK FORT SMITH DIPICTION TURIER 6 TURNER 7 TURNER 6 TURIER 7 N 26 6 9 7 UNE 18 13 25 12 IE 34 16 136 48 ENE 23 15 78 31 E 28 19 27 11 ESE 43 17 10 6 SE 44 14 15 13 SSE 35 8 15 5 S 29 10 26 15 SSW 15 6 20 9 SW 36 12 13 19 WSW 88 33 28 12 W 26 9 8 6 MM 3 2 1 2 W 0 2 5 3 NIM 10 1 0 3 CALM 106 259 68 264 NOTE: Months selected as highest No. of calms in 10 years Little Rock conths are Oct 1963, Aug, Sep, Nov 1964 Forth Smith months are Aug, Sep, Oct 1960, July 1961 0220 2A.41 L
2A.10 DIFFUSION MODELS TIZERAL The general diffusion exprescion for calculating air borne concentration along the plume axis was discussed. The equation in 3 X/Q=1/(ff +CA)u,sec/m For the Russellville site, the distance to the site boundary is 1050 meters, to the low I.opulation zone is 72,000 meters and to the popu-lation center at Little Rock is 96,000 meters. These are the distances used to obtain the standard horizontal and vertical deviation of the 2 plume. The value used for the cavity effect, CA, is taken as 3700 m, the minimum area of the power plant buildings. The following paragraphs discuss the method and results of the calcu htion of the two-hour, twenty-four hour and one-month diffusion models. TUO HCW MODEL Prom 10-years of hourly climatological data from Fort Saith and Little Rock veather stations, 8 months are identified as having the h1 chest frequency of ca b, and the highest frequency of poor diffusion con-ditions with Turner category 5 and 7 7.ie lowest monthly average vind ,I speed during periods of Turner 6 or 7 is 1 meter per second, including l cab as zero. The values of 0)[anddfare taken from Slade20, The results are shown below. TWO-HOW MODEL Site Lov Pop. Little Boundary Center Rock Horizontal diffudion, @ m 39 1,600 e,100 Vertical diffusion,Oi,m 15 86 94 i Unit X/Q, (Q:1) l.8 x 10 -'+ 2 3 x 10-u 1.o x lo-o For the two-hour model, stability is assumed as Pasquill F, persisting for two consecutive hours from the same direction. For two hours, the av-erage hourly X/Q should be multiplied by two. TWEIITY-F0W HOW MODEL The twenty-four hour diffusion model is derived frcra a review of all the individual days in the eight months of highest frequency of calms, described above. The four days finally selected are the only ones ex-hibiting Turner 7 category persistent all night long. These days are shown below. M 0721
1. Fort Smith, Aus 31(1900to2300),1960 Aug 30 (oooo to 1800),1960 2. Fort Smith, Sept 5 (1900 to 2300),1960 Sept 4 (oooo to 1800),1960 3 Fort Smith, Sept 29 (oooo to 2300),1960 4 Fort Smith, Oct 26 (1800) to oct 27 (1700), 1960 It can be seen that some of these " days" were actually not of consecutive nighttime hours. This is because, of all the 240 days surveyed, only one day, number 4 in the list, exhibits a truly consecutive Turner No. 7 sequence of nighttime hours. The other three days are included to obtain a more representative sampling for analysis. To obtain the hourly wind speed of the model day, the arithmetical average of the individual days is calculated. The mean hourly wind vec-tor is calculated to establish the wind direction for each hour of the model day. Likewise, the Pasquill letter for each hour of the model day is taken from the average of the Turner numbers of the individual days. The determination of the hourly standard horizontal plu=e deviation, Oh, is based on the averaged Pasquill category and,othe distances established previously. The numerical value is from Slade c A similar method is used to obtain one set of values for the vertical deviation,6. This y is compared to hourly averaged mixing depths as detemined from radio-sonde and surface temperature measurements at Little Rock for the days in question. The lesser of the two values is taken for Og~, for each hour. Essentially, then, a canposite 24-hour day model is established, and X/Q values calculated for each hour. In addition, for each hour, a composite wind direction is calculated. Finally, all the X/Q values for each direction are summed. The summation for X/Q for a given direction that yields the highest value establishes the highest exposure for the 24-hour model. Direct,ionality thereafter loses its significance and, once having been used to establish the highest X/Q, it is thereafter assumed that this X/Q could apply in any direction. The results of the analysis are shown below. 24-Hour Model Ave Wind X/Q, (Q = 1), sec/m3 Pasquill
- Speed, Site Low Pop.
Little Hours Category mps Boundary Zone Rock 5* F 1.0 10.2 x 10-0 13.0 x 10-6 9,1 x 10-6
- It should be noted that in 99.2 percent of the time, the wind has a persistence in one direction of five hours or less, see Table 9 5.
0222 2A.43
?;r the 24 hour mgdel, the sum of the X/Q, for the indicated periods, is 10.2 x 10~g sec/m, at the site boundary. Thus, the average hourly X/Q for the 24-hour model is 4 3 x 10-5 sec/m3, 30-DAY MODEL The 30-day diffusion model is developed by a method quite similar to the 24-hour model. From 10 years of climatological data, it was previously pointed out that the month of October, for both Little Rock and Fort Smith, contained the highest frequency of cabn surface winds. In addition, an analysis of averaged monthly hourly data for Little Rock for the years 17)3 and 1934 shows the total number of Pasquill F hourly occurrences is August, 18; September, 20; and October, 26. These are the three months of highest number of Pasquill F occurrences from averaged monthly hourly data. Analysis of radiosonde data for Little Rock for 1953 and 1934 shov October the month of most inversions dn the falls It is shown that October is the month of most adverse diffusion climatology. However, to approximate the most adverse quarter of the year, the months of August, September and October of 1%3 and 1%4, for Li'+1e Rock, are selected for analysis. Based on averaged hourly data (Local Climatological Data, Supplementl2), for each of the six months, each hour is categorized into the appropriate Turner number. These six averaged days, representing the months of August, September, } and October,1%3 and 1%4, are then composited into one average day by / the method described for the 24-hour model. Similarly, the standard plume deviations, and , are determined as before, except that the daytime upper to is taken as the mean maximum mixing depth (!dD) determined by Holzvorth, for Little Rock, for the month of October. In addition, the MMD is reduced by one-half in the morning hours to account for gradual increase in the mixing depth during the morning hours. "he product of this analysis is a composite day of the 1-month model. 's before, X/Q nlues were calculated for each hour,and for each hour a composite vind direction was calculated. The X/Q values from each direction are then summed and compared. The highest value yields the highest exposure for the composite day of the model month. This X/Q is assumed to apply in any direction. The results of the analysis are shown below. 02 5 ai.uu L
g COMPOSITE DAY OF THE MoDEL MCIITH X/Q,(Qel),sec/m3
- Wind, Pasquill
- Speed, Site Low Pop.
Little Heurs Category mps Boundary Zcne Rock ~5 h F 2.0 3.6 x 10-4 4.5 x 10 3 2 x 10-5 These results show that for the gypical day in the 30-day model, the sum of the X/Q is equal to 3.6 x lo sec/m after sumation over the four hours of the typical day, at the site boundary. Thirty of such days would ccrnprise the 30-day model. Thus, the avera6e hourly X/Q for the day model at the site boundary is 1 5 x 10-5 sec/m3, SU!G!ARY, SITE DISPERSION FACTORS Table 2A.20 shows the site dispersion factors, average hourly X/Q versus ~ distance, for the two hour, twenty-four hour and the 30-day diffusion models. The site boundary is 1050 meters from the plant. The City of Little Rock is 96,000 meters away. The factors shown in Table 2A.20 were all calculated as discussed in the earlier portions of this chapter. i s 0224 .p 2A.45
r.~ ?- ./ / TABLE 2A.20 s SITE'DISFERSION FACTORS '(Ave Hourly X/Q, (Q = 1), sec/m3) Distance Diffusion Models Meters 2 Hours 24 Hours 30 Day' 525 2.4 x 10-4 5.6 x 10-5 5 1050 1.8 x 10-4 4.3 x 10-5 2.0 x 10 5 1,5 x 10-3000 8.o'x 10-5 5 1.9 x 10 6 6.7 x 10-6 5 4.8 x 10-1,7 x 10-6 10000 2.0 x 10 6 25000 7.6 x 10 6 1.8 x 10-6 6.3 x 10-7 5o000 3.4 x 10-8.1 x 10-7 2 9 x 10-7 72000 23xlo-h 5.4 x 10-7 1 9 x 10-7 96000 1.6 x lo-3.8 x 10-7 1 3 x 10-7 0 0225 h 2A.46 C' M
? ./ 2A.ll RECOMMENDATIONS GENERAL The data from the U.S.W.B. s tations at Little Rock and Fort Smith are the major sources of information upon which the conclusions of-this report are based. Other data sources, such as Little Rock AFB and Russellville weather stations, were examined and used as judgment indicated. It is believed, from a review and analysis of the data and inter-pretation of the results, that an adequate understanding of the site climatology has been obtained to support the Preliminary Safety Analysis Report. It is also believed that additional on-site data are necessary to confirm initial estimates of site dis-persion factors. For this reason, an on-site meteorology program is underway. A portion of the program started operation in the Fall of 1967. The instrumented tower program commenced operation during the Summer of 1969. This program is discussed in the following paragraphs. 17 EARLY PROGRAM To obtain early weather data, a single wind speed and direction sensor has been installed at the site. The wind speed sensor is-of the high sensitivity type, with a threshold of 0.5 mph. The recorder is set'at full scale of 30 mph for highest accuracy in the low velocity ranges. Both wind speed and direction are re-corded. c The. location is approximately 0.4 miles east northeast of the proposed power plant. The instrument is mounted o.n a wooden pole at a ground elevation of approximately 380 feet. l This installation is a temporary measure, to permit earliest collect 4on of the meteorological data. As soon as the full program is started, this early program will be discontinued. i METEOROLOGICAL TOWER PROGRAM A meteorology tower 190 ft high is located 1500. f t due east of the reactor building. Details of this tower are described 17 in the program Status Report starting on page 2A.54. 0226' ^ - 5 4 -70 llll 2A.47 Supplement No. 17
The criteria for tower location were as follows: - Elevation same as site. - Exposure of tower approximates exposure of the reactor structure after construction. - Location of tower upwind from site for best location for determination of Pasquill category F. - Relation to water, hills, etc., same as site. Wind mea:;urements are being made at elevations close to the power plant grade surface and the top of the main vent. The meteorological instruments mounted on the tower include: i - Two wind recording systems, one mounted at 20 feet and one mounted at 190 feet above ground elevation. These continuously measure and record wind speed and direction. - A temperature recording system. This measures and records the tempera-ture differences between 5 feet and 85 feet, and between :s feet and 190 feet. ) l - A precipitation sensor to record the occurrence of non-occurrence of precipitation. 'Ihis is mounted at 20 feet above ground elevation. 17 A recorder shack is erected on the tower site to provide housing for the two wind recorders and the temperature-precipitation recorder. The shack is erected close to the tower but sufficiently removed to ensure its not affecting the atmospheric conditions in the vicinity l of the tower. The meteorological data collection and analysis effort are summarized below: - The chart data collected on site is reduced to h'ourly tabulations suitable for machine processing. This will consist of the early program, which lasts for more than one year, and enough readings to corre13,te this observation station to the main tower. The main tower program will last for a period of one year. Comparative data is acquired from the Local Climatological Data published for Little Rock and Fort Smith. 2A.48 5-4-70 Supplement No. 17 m M OZM
- Windrose diagrams and tables for the early program (30-feet) will be prepared. Sn maries will be prepared including annual windrose dia-grams for 20 and 190 feet during conditions (1) all stability cate-gories and (2) precipitation occurrence vs. precipitation non-occurrence (observations used total 100%) and all observations without stratifi-cation. - Sumaries will be prepared of the annual windrose diagrams and tables for Little Rock and Fort Smith and comparisons will be made between these and the on-site early program (30-foot) and the tower program (20- and 190-feet) levels. - Summaries will be prepared of the hours of persistence of wind direction at the 20- and 190-foot level of the tower at the site by 17 0 22 5 sectors for all stabilities combined. - Summaries will be prepared of the hourly reports of low wind speeds at the site and compare to the LCD reports frcm Little Rock and Fort Smith for winds of calm, 1 knot, 2 knots and 3 knots speed. - Su== aries and comparisons will be prepared on the frequency distri-bution of Pasquill stability categories for the 20, 30- and 190-foot levels at the site by the Slade method; the 0-85 foot and the 0-190 foot levels at the site by the Markee method; and Little Rock and Fort Smith by the Turner method. REPORTS The first report of the on-site progrem is submitted as part of Supple-ment No.17 and the final sum =ary report will be submitted in late 1970. 2A.49 5-4-70 Supp g t No. 17
.~: ... w
- 4.9 ;.
% N. l. -u ~ ~ i
- 7,.
2A'.12 . c. MhE:;CE3 - v 1. Franklin Ccunty Climatological Survey, prepared by INSA,. U.S.W.B., ' Little Rock, Arkansas 2. '. Climatography of the United States, No. 86-3, Suppleent' for 1951 through.1960, Arkansas, USCCM, ESSA, WB ^ 3.- Selected C16 tic Maps of the United States, USCCM, ESSA, ECS' ~ ~ 4.'- ~ Local Climatological Data, Annual Sumary with Comparctive' Data,- 1966; Fort Smith, Arkansas, USCOM, ESSA, EDS 5 . Local Climtological Data, With Conparative Data,1960, Little Rock, Arkansas, USCCM, WB 6. Tornado occurrence in the United States, Technical Paper No. 20, September, 1952, USCOM, WB 7. Tornado Frequency by States, hap 1953-1963, USCOM, WB, Revised January 1965 ^ .e
- 8. -
. Tornado Distribution in the United States, Map, USCOM, WB, Revised' ~ 3 ' April'1960 / 9 Tornadoes 1916-l%1 (By 1 Degree' Squares), Map. USCOM, WB, Revissd April 1962 s-10. .' Percentage Frequency of Wind Direction and ' Speed, Percentage ' Frequency-of Wind Speeds at Various Hours through. the Day, Duration and Frequency of'Cah and Near-Calm Winds, Precipitation Frequency of Wind Direction and Speed, Little Rock and Fort Smith, January 195! December 1963, Job No. 7923, USCcM, E3SA, EDS, :.wrx, t Ashville, North Carolina, August 2,1967 11. Climatic Snerny, 1931-1960,30-YearNormal,USCCM,bSA,'WB ^ ~
- 12.
Local" Climatological Data and ' Supplement, January 1956 to December [ ' 1965,'Little Rock, Arkansas-(Adams Field) and Fort Smith, Arkansas ' (Municipal Airport), U. S. Weather Bureau ~ D * }, ceze u 2A.50 { Y. i .. =. =.
- ~. ' 13 Wind Gust Recordings-(Continuous Trace),.Little Rock AFB, Arkansas, September-October,1964, USCOM, ESSA,,IMRC, Ashville, North Carolina' 14. Sutton,~O. G., Micrometeorology, McGraw-Hill Book Company, 1953-15. 'Pasquill, F., Atmospheric Diffusion, D. Van Nostrand Co. Ltd., London, 1962' 16. Culkowski~, W. -M., Nuclear Safety, Vol. 8, No. 3, Spring,1%7,
- p. 257 17 Dickson, C. R.; Start, G.E., and Markee, E.
H., Aerodynamic Effects of the EBR-II Containment Vessel Complex and Effluent Concentrations, USAEC Meteorological Information Meeting, Chalk River Laboratories, Ontario, Canada, September 11-15, 1 % 7 18. .Pasquill, F., The Estimation of the Dispersion of Windborne Material, The Meteorological Magazine, Vol. 90, No.1,n63, February 1961, p. 33, Meteorological Office, Air Ministry, England '19 Turner, D. Bruce, A Diffusion Model for an Urban Area, J. Applied Meteorology, Vol. 3, No.-1, February 1964, p. 83 20. Slade, David H., Estimate of Dispersion from Pollutant Releases of a Few Seconds to 8 Hours in Duration, Technical Note 39-ARL-3, Institute for Atmospheric Sciences, USCOM, ESSA 21. Holzworth, George C., Estimates of Mean Maximum Mixing Depths in the Contiguous United. States, Monthly Weather Review, Vol. 92, No. 5, May 1964, pp. 235-242 22. Gifford, Jr., F. A., Atmospheric Dispersion Calculations Using the Generalized 'laussian Plume Model, Nuclear Safety, Vol. 2, No. 2, December 1960, p. 56 0230 '2A.51
SUPPLEENT TO METEOROLOGY REPORT PRELDGARY SAFETY ANALYSIS REPORT ARKANSAS PWER & LIGHT CO. This additional discussion has been prepared to illustrate the effect of cavity diffusion downwind of the station buildings on the relative con-centration,X/Q. Various investigators using wind tunnels and/or with full-size buildings, have studied the cavity diffusion phenomenon on the dilution of plumes down-wind from buildings. The enhanced dilution due to the turbulent flow around or over the buildings is accounted for by the CA term in the diffusion equation, where C is empirically determined and A is the cross sectional area of the buildings perpendicular to the wind. The empirical factor C has been detemined by measuring concentrations and/or turbulence parameters downwind from buildings. The factor varies with atmospheric stability, downwind distances from the building and wind speed. The avaihble data (reference 16 and 17, Appendix 2A of the PSAR) indicate that C usually lies in the range of 1/2 to 2 for stable atmospheric conditions. We believe there is little justification for choosing any particubr value within this range; thus we choose a value of C=1.0 as repre-sentative of the range. (When the atmosphere is unstable, recent experiments reported by C. R. Dickson, reference 17, indicate that C is in the range of 2 to 15.) The minimum cross sectional area of the station building complex is 3700 square meters. Of this, 2205 square meters is of the reactor contaiment building. For the calculation of the relative concentration, X/Q, in the PSAR, the minimum cross sectional area of the total building complex was used. The general arrangement of the buildings is shown in Figure 1-3 of the PSAR. It is seen that the reactor containment building is located within the in-cluded angle of the L-shaped building arrangment. Furthermore, the reactor containment building is connected to and is contiguous with both the Fuel Handling Building and the Turbine Building. As observed frcm the power station physical arrangement, it is not feasible to separate the reactor containment building frcm the other buildings when estinating the effect of cavity diffusion phenomenon. The sensitivity of X/Q to changes in the building factor, C, and the building area, A, have been examined. The effect of wind direction persistence has also been studied. The results are shown in the following table. 1 2 3 4 2 Reactor RB=2205m, Wind Direction Building Only, C=1/2; Persistence 2 PSAR Report C= 1/2, 2 Ba1.=1495m, Data PSAR 2 C=1, A=3700m A= 2205m C=1.0 Page 2A-40 _4 -4 HourlyX/Q 1.8 x 10_4 3.4 x 10_4 e;2 3 x 10_4 g g 1.45 x 10_g TwoHourX/Q 3.6 x 10 6.8 x 10 ' 4.6 x 10 2.9 x 10 2-Hr Dose, at i 1050 meters, rem 224
- 423 286 180 Dose of 224 rem is shown in PSAR, Fig. 14-73.
g 2-8-68 2A.52 Amendmen, No. 1 ^'
Column one of the table shows the hourly and two-hour values of X/Q and the two-hour dose at the site boundary,1050 meters, as described in the PSAR. s Column two shows the results when a C factor of 1/2 is used with only the . reactor building area considered. ColumnthreeisconstructedusingC-1/2 for the reactor building and C-1 for the remainder of the buildings. Relative to column four it is noted from Table 2A-40 (Meteorology Appendix, PSAR).for the eight worst months of ten years of record, identified on the basis of reported hourly calm surface winds, that during these months 76% of the time the wind was unidirectional for only one hour, and that 24% of the time the wind was unidirectional for two hours or longer. If the effect of wind persistence ~btained.g5x10gsincludedinthecalculationofthecolumnthreecase X/Qof1. or a two hour does at the site boundary of 180 rem is o An evnmhtion of the table indicates that the meteorological analysis of the diffusion conditions at the Russellville site contains enough conservatism to allow for a reduction of the C factor from a value of one for the curved reactor building to a value of one-half. It is not at all clear that a C=1.0 for the rectangular turbine and fuel buildings is not conservative enough. It should be noted that either column three or four leads to estimates of f dose at the site boundary.that are less than the guideline value of 300 rem to the thyroid. 2. Basis of calculation as follows: 1/2f076(2.3x10 ) +0.24 (4.6 x 10 )j=meanhourlyX/Qincluding wind direction persistence effect. t 0232 M i v 2A.53 2-8-68 c Amendment No. 1
a ARKANSAS POWER & LIGHT COMPANY ARKANSAS NUCLEAR ONE STATION ~ ONSITE METEOROLOGICAL PROGRAM STATUS REPORT November'1969 81.13 The onsite meteorological program at the Arkansas Nuclear One Station site was initiated to supplement and quantify the . meteorological site study reported in the Preliminary Safety Analysis Report, detailed in Appendix 2A thereof. The onsite program consists of two parts:
- 1) the early program and 2) the meteorological tower program.
This status report describes the two programs including equipment employed, method of collecting and evaluating the raw data and the status of comparison of site meteorology with the assumptions used in the PSAR. The Early Program The early program equipment and location is as described on page 2A.47 of the PSAR. The wind system employed is a Beckman and Whittey Model WS-101. The sensors are located at El. 30' above grade. The system has been in continuous operation since September 1967, except for some extended periods of instrument malfunction, particularly the Wind direction sensor. It is intended that this system will operate for a full three-month period in parallel with the tower program to permit correlation of the data. As of now, this parallel operation has not been achieved due to malfunctions of the instruments. This program was initiated at the earliest possible time (prior to installation of the tower system) to obtain
- 1) obser-vations of wind speed and direction,
- 2) frequency and duration of calms, and
- 3) estimates of Pasquill diffusion category by j
the method of Slade. (note 1. ) The equipment is operated by Arkansas' Power and Light Co., the data is analyzed by Bechtel Corp. and the results are interpreted by consulting meteor-ologists Drs. J. B. Knox and T. V. Crawford. The raw data is i read directly from the recorder strip charts, with spot wind speed and direction taken at the hour and 30-minute direction range taken from 15 minutes before to 15 minutes after the hour,iaccording to Reference 1. Observations are made on a three-hourly basis for comparison with U.S. Weather Bureau, three-hourly local climatological data for Little Rock and Fort Smith, Arkansas. Note 1. Slade, David H., Estimate of Dispersion from Pollutant Releases of a Few Seconds to 8 Hours in Duration, Technical Note 39-ARL-3, Institute for Atmospheric Sciences, USCOM, ESSA.,. t h 0?33 2A.54 \\ 5-4-70 \\ l Supplement No. 17
Seasonal and Annual reports are prepared for the early program. The data is shown in Tables 1-4 inclusive. The 196,8 Annual report summary follows as illustrativa cf the progress achieved. e The features, characteristics and comparisons to the PSAR are found in the annual distributions of data. All the analysis and evidence compiled to date in.the early program indicate that the diffusion and meteoro-logical assumptions of the PSAR are. conservative. The evidence of this is as follows: .l. _The site surface wind is directed away from Russellville with twice the frequency that.it lis directed from the plant towards Russellville. 2. When the wind is directed towards Russellville t.he wind is about 25 percent stronger than G for all directions. 3. The annual mean wind speed, G, under Pasquill F condition, is 2.1 meters per second whereas the PSAR 2-hour model assumed 1 meter per second. 4. The annual frequency of Pasquill F (Turner 6-7) ~ is 2.8 percent; whereas it is calculated from eight months of data,, Table 2A.19 PSAR, that j the annual frequency of Pasquill F for Little / Rock is 6.3 percent and for Fort Smith is 5.8 percent. 5. Pasquill A occurs 17 percent of the time whereas zero was assumed in PSAR 24-hour model. In table 3 are shown comparisons of stability category by various methods. The methods are defined as follows: a. "Russ Slade" is determined from continuous wind record data from the site using the Slade method. b. "Russ LIT" is determined from the hourly site wind speed data and Little Rock hourly sky condition as reported by the U.S.W.B., using the Turner method. (note 2.) c. "Russ FSM" is same as b.) except Fort Smith. sky conditions are used. Note 2.
- Turner, D.
B., "A Diffusion Model for an Urban Area", J. App. Meteo,,Vol. 3, No. 1, Feb.~ 19 6 4, page 83-91. ~
- w..
g r' t 0234 2A.55 5-4-70 Supplement No.-17
d. " LIT LCD" is determined by Little Rock 3-hourly sky conditions and wind from the Local Climatolo-gical Data, using the Turner method. O e. "FSM LCD" is same as d.) except Fort Smith LCD is used. Table 4 shows the persistence of Pasquill F stability cate-gory based on data derived from Slade's method using three-hourly site data, Annual, 1968. The data shows that during 1968, on a three-hourly basis, 44 events of Pasquill F category occurred. This table also shows that only ten percent of the three-hourly Pasquill F category events per-sisted to the next three-hourly observation. Further, during 1968, there were only two periods of Pasquill F of durations, longer that the first three-hourly period, that were uni-directional. Hence, it appears that the Arkansas Nuclear One site had diffusion characteristics during 1968 that were considerably better than those assumed in the PSAR twenty four-hour model of five hours of Pasquill F. After reviewing all of the early meteorological program data, the consultants find no evidence, analysis result, or trend that indicates that the diffusion models employed in the PSAR are not adequately conservative. We expect as the meteorology tower data and analysis results are developed, j that Slade stability category frequency data will continue to substantiate this conclusion. 1 6 B 0235 W ~ 2A.56 5-4-70' auveramusJs
TABLE 1 I PERCENT FREQUENCY OF WIND DIRECTION AND SPEED ANNUAL 1968 RUSSELLVILLE NUCLEAR SITE l Il'! Speed, Knots Total Mean { Direction 0.4-3 4-6 7-10 11-16 17-21 Frequency Speed N 2.7 1.4 0.3 0.1 0 4.5 3.6 NNE 2.5 1.1 0.5 0 0 4.1 3.5 PS 3.9 0.5 0.4 0 0 4.8 2.8 ENE 5.0 2.3 0.8 0 0 8.1 3.2 j E 7.8 5.3 1.4 0 0 14.5
- 3. 3-ESE 5.4 3.0 0.7 0.2 0
9.3 3.6 i SE 3.6 2.5 0.9 0 0 7.0 3.8 i i SSE 3.1 2.7 0.9 G.4 0 7.1
- 4. 4-
]i S 2.3 2.4 1.0 0 0 5.7 4.3 SSW 0.9 1.1 0.8 0 0 2.8 4.7 SW ~ 1. 0 0.4 0.5 0 0 1.9 4.2 WSW 1.5 0.8 0.7 0.1 0 3.1 4.4 f W 3.4 1.4 1.8 0.7 0.1 7.4 4.6 I WNW 2.1 2.1 1.3 0.8 0 6.3 5.4 NW 2.2 1.1 1.1 0.3 0 4.7 4.4 NNW 2.0 0.9 0.9 0.2 0.1 4.1 5.2 Calm 4.6 i i i Total 49.4 29.0 14.0 2.8 0.2 100.0 3.9 Notes: 1. Based on observations recorded every three. hours 2. Table is derived from the averages of the four seasonal means 3. Recorded observatilons are 60 percent if possible ] l 4. Data is December 1967 through November 1968 l M w 9 -70
TABLE 2 FREQUENCY AND DURATION OF CALMS ANNUAL 1968 RUSSELLVILLE NUCLEAR SITE Percent Total Total Calm of Duration Hours Hours Total Hours Frecuency Recorded of Calm Recorded Hours 1/6-1 528 308.1 1-2 51 76.5 2-3 10 25.0 3-4 6 21.0 4-5' 2 9.0. 6-7 1 6.5 8,9 1 8.5 14-15 1 14.5 Total 600 6,867 469.0 6.8 Notes: l '. Total hours recorded is every hour on the chart 2. Duration, hours, is all hours shown on the chart ~ 3. Data is for December 1967 throuch November 1968 0237 .i 2A.5b 5-4-70 Supplement No. 17
s TABLE 3 7 PERCENT FREQUENCY OF TURNER NUMBERS ANNUAL 1968 RUSSELLVILLE NUCLEAR SITE 4 i I Pasquill Russ Russ Russ LIT FSM Catngory Slade LIT FSM LCD LCD i A 17.6 1.9 2.3 1,. 0 0.2 'B 8.7 12.6 12.1 6.5 8.3 C 20.4 20.0 19.1 14.0 12.2 1 -[j 3 D 34.0 35.5 37.8 53.6 53.8 E 16.5 6.6 4.4 10.5 7.7 I F 2.8 23.4 24.3 14.4 17.8 t Total 100.0 100.0 10d.0 100.0 100.0 i Notes: l. Based on observations recorded every 3 hours 2. Recorded observations are 59 percent of possible 3. If, for a given hour, any of the five cases lacks an observation none of the cases is used Q'Z.o g a-4. Table is the average of the four seasonal tables -) M 2A.59 } 4 -70 )
TABLE 4 PERSISTENCE OF PASQUILL F CATEGORY ANNUAL 1968 SUF31ARY RUSSELLVILLE NUCLEAR SITE Winter Hour 2 Hour 5 Hour 8 or Greater Comments 10 2 0 One of the two events persisting to 5 hours was unidirectional. Spring Hour 2 Hour 5 Hour 8 or Greater 11 0 0 None. Fall Hour 2 Hour 5 Hour 8 or Greater 19 2 0 One of the two events persisting to 5 hours was unidirectional. Annual Hour 2 Hour 5 Hour 8 or Greater 40 4 0 None. Note: No category F conditions reported for summer, 1968. When an even't is observed on a 3-hourly basis, it is presumed here to occur for two hours duration. ~ 0239 M 5 4 -70 2A.60 Supplemeat No. 17
The Tower Program A 190-foot high instrumented meteorology tower has been' placed in operation at the site. The tower is located at north latitude 350 18'-37" and longitude 930 13'-20" at a i position 0.51 miles due east of the reactor building. The tower instrumentation includes sensors to measure wind direction and range, wind speed, air temperature and dif-ferential temperatures and the occurrence of precipitation. The wind sensors are located at the 20-foot and the 190-I foot levels. The temperature sensors are located at the i 5-foot, 85-foot and 190-foot levels. The precipitation sensor is located at the 20-foot level. The wind direction instruments are Litton Model 510D-2 sensors utilizing Model 510V-4 vanes. The wind speed instru-ments are Litton Model 5115-4 sensors utilizing Model 510C-2 stainless steel cup assemblies. The temperature sensors utilize precision resistance bulbs mounted in ventilated solar radiation shields. The precipitation sensor consists of two printed circuit grids and the occurrence of precipi-tation reduces the electrical impedance of the circuit. The sensors output are recorded on analog strip charts housed in a steel instrument building. This building is kept at constant temperature by air conditioner / heat' pump equipment. J-Litton Systems, Inc. supplied all of the installation. They acquire the data from the charts, analyze same and prepare reports of the data and their meteorological interpretation. i AP&L service the equipment. Bechtel's meteorological con-sultants, Drs. J. B. Knox and T. V. Crawford, review the over-cl1 program results. The first full month of tower data analyzed was June, 1969. Subsequent intermittent instrument malfunction has prevented attaining an unbroken record of data. To date, the data analysis has covered an insufficient period of time to permit a comparison between the PSAR meteorological study results and the tower results. ' ~ 0240 1 2A.61 5-4-70 Supplement No. 17
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