ML19326D036
| ML19326D036 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/17/1971 |
| From: | Van Der Hoven COMMERCE, DEPT. OF, NATIONAL OCEANIC & ATMOSPHERIC |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19326D013 | List: |
| References | |
| R323, NUDOCS 8004300657 | |
| Download: ML19326D036 (3) | |
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' September 17, 1971 Silver Spring, Maryland 20910 50-3 M g g g 4 3 gg6d g
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B-Dr. Peter A. Morris, Director T
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Division of Reactor Licensing U.s. :.::n ' !.T
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Dear Dr. Morris-o.
This refers to the letters of Fei,:uary 17, 1971 and April 15, 1971, from ltichard C. DeYoung Assistant Director _for Pressurized Water Reactors of the Division of Reactor Licensing, reque 3 ting comments on the following:
Arkansas Nuc1 car One Unit 2 Preliminary Safety Analysis Report Supplement 2 dated February 3,1971 Supplement 3 dated March 31, 1971.
These comments are attached.
Sincerely, h- < < c 6b 6
't Wes Isaac Van der Hoven, Chief Air Resources Environ!cental Laboratory Air Resources Laboratories Attachment cc:
E. H. Markce, USAEC t
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l Comments on Arkansas Nuclear One Unit 2 Preliminary Safety Analysis Report Supplement 2 dated February'3, 1971 Supplement 3 dated March 31, 1971 Prepared by Air Resources Environmental Laboratory National Oceanic and Atmospheric Administration i
September 15, 1971 The 33-month onsite meteorological data collection program indicates a high percent of low wind speeds and surface-based inversions as The average compared to the average for this portion of the country.
wind speed at 30 feet was found to bc 2.2 m/s as compared to the average of 3.6 m/s for this portion of Arkansas [1].
Calm was found to occur 7.6 percent of the time, presumably primarily at night under inversion conditions. Stable conditions as measured for one year by the temperature difference.betueen 5 and 190 feet showed a 78.8 percent frequency with lapse rates greater than -0.5 C/100 m.
When lapse rates were measured between 85 and 190 icet the frequency decreased to 51.5 percent. Hosler [2] shows about 35 percent for this area.
The initial data period from September 1967 through September 1969 shows about a 50 percent data recovery record with the entire summer of 1969 missing as well as half the summer of 1968.
Since the summer season tends to have lower average monthly wind speeds as shown by Little Rock, Fort Smith, and Texarkana data [3], the annual average for the site may be lower than 2.2 m/s.
The later data period from June 1969 through May 1970, where winds.at 20 feet and temperature differences between 5 - 190 feet and 85 - 190 feet were measured, is equally difficient with wind data for only about 1/4 of the summer availabic.
that is Taking the June 1969 through May 1970 onsite data as the best currently availabic, the record shows that 5.3 percent of the time wind speeds were below 1 knot with lapse rates greater than 1.5 C/100m as measured between 85 and 190 feet. We interpret this to mean that downwind concentrationn from a ground source equal to or greater than that equivalent to Pasquill Type F and 0.5 m/s wind speed will occur 5 percent of the time. We have not used the applicant's horizontal wind direction fluctuatio'n (op) categorization shown in Table 2.A-20 because 14.2. percent of the observations are listed as non-steady traces occurring at night under inv'ersion lapse rates.
Presumably, most of the " calm". cases arc included in this frequency and since no wind sp' ed distribution was given we are unable to classify these c
' situations satisfactorily by the sigma theta and wind speed technique.
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For the 0-2 hour release period we have assumed a ground release, c.
. diffusion parameters equivalent to Pasqui}l Type F and 0.5 m/s and a building wake factor of cA = 1102 m.
The resulting concen-tration at the exclusion distance of 1046 m is 7.3 x 10-4 see m-3 For t'he 30-day release we have used Tabic 2.A-5 to estimate a maximum monthly frequency of 25 percent for winds from the east and assumed that the diffusion conditions were equally divided between Pasquill Types F, D, and C at wind speeds of 2, 3, and 3 m/s, respectively. The resulting concentration at the low population distance of 6436 m was 4.4 x 10-7 see m-3 For the annual
, concentration we have made the assumption that on the average, neutral diffusion conditions would exist at a mean wind speed of 2.2 m/s with a 15 percent frequency of wind from the east sector.
The resulting ccacentration at the exclusion distance is 4.1 x 10-6 see n-3,
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,In summary, our estimates of downwind concentrations are a factor t
of from 2 to 6 times higher than that of the applicant, with the largest difference beind ir the 0-2 hour relcase computation.
We.
have numerous difficultics '.ith the onsite data so far presented and would like to make another evaluation on a subsequent year of data comprising of at least 90 percent of the possible observations.
References
[1]
U. S. Department of Commerce, " Climatic Atlas of the United States." ESSA Technical Report, 80 pp.,
1968.
[2]" '11osler, C.
R., " Low-level Inversion Frequency in the Contiguous 8,,
319-339, 1961.
9 United States." Mon. Wea. Rev.
[3]
U. S. Department of Commerce, " Local Climatological Data" Little
' Rock, Fort Smith, and Texarkana, Arkansas, Weather Bureau P.ublication, 1964.
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