ML20009G980
| ML20009G980 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/03/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| References | |
| RTR-NUREG-CR-1389, TASK-02-02.A, TASK-2-2.A, TASK-RR LSO5-81-08-002, LSO5-81-8-2, NUDOCS 8108050322 | |
| Download: ML20009G980 (3) | |
Text
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August 3, 1981
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- 3y to Docket No. 50-29 y
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D 4 05 GG1m se Mr. James A. Kay
"@h Senior Engineer - Licensing
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Yankee Atomic Electric Company I
25 Research Drive T
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Westborough, Massachusetts 01531
Dear Mr. Kay:
SUBJELT:
YANKEE R0WE - SEP TOPIC II-2. A, SEVERE WEATHER RENOMENA By letter dated scember 17, 1980, we fomarded to you our draft evaluation of SEP Top k II-2.A, " Severe Weather Phenomena".
Your response dated February 10, 1981, stated that you concurred with our as,essment except for the evaluation of snow and tornado loadings.
Regarding the snow loadings you stated that the local terrain effects would result in values much lower than those provided in our evaluation and requested that we re-evaluate the snow loadinos accordingly.
The snow load value for the site region has been recently studied as part of a NOAA Study, " Estimating Water Equivalent Snow Depth frem Related Meteorological Variables," (NUREG/CR-1389, May 1930),whi-h chcas the 100 year snow Toad in that area to be from 50 to 60 lb/ft'.
Cautions are I
advised in the use of interpolation of the isopleths, in this mountainous area, since local topographic influences can affect snowfall totals.
Similarly, structural effects on drifting snow can result in higher or lower loads than shown for ground level snow loads in this NOAA report.
Additional research on snow loading is being completed through use of actual field studies on power plant structeres in the northeast and the Great Lakes areas.
Thus, subject to additional information resulting from these studies, the snow loads defined in our December 17, 1980 evaluation, S$2 1.e., normal of 40 lbs/f t2 and snow load combined with probable maximum 2
winter orecipitation of 125 lbs/f t, should be used for structural response 88 g
analysis.
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Your comments reqarding the design basis tornado are similar, indicating gg that terrain effects will significantly effect the tornado wind loadinas epk gE J
no and frequency.
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oj The tornado analysis ay Mcdonald (Enclosure 2 of our December 17, 1980 ed" ou letter) conridered 224 tornadoes, during the oeriod from 1950-1978, that px occurreo in the 3x3 degree square area roughly centereJ about the Yankee
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' Rowe site. This analysis suggests an upper bound 95 percentile tornado wind speed, with a 10-/ probability level of approximately 300 mph is appropriate. This value is the suggested wind speed at the site, for the analysis of structural design capability.
Inherent in the Mcdonald tornado analysis are weighting factors for population density, storm intensity and topographic features that could effect the observation of any tornado. Selection of a 300 mph upoer 95 percentile wi'nd speed 250 mph for the 10 pism beyond the expected value of approximately provides a conserva probability level.
In addition, the outbreak of tornadoes in Kentucky and Tennessee during April 3 and 4,1974 indicates that tornadoes can occur in mountainous terrain.
Based on the studies mentioned above, we do not feel that you have provided sufficient justification for us to change our earlier evaluation provided on December 17, 1980. Therefore, we consider that evaluation to be final and Topic II-2. A to be completed.
1 The evaluation will be a basic input to the integrated safety assessment for jour facility. The assessment may be revised in the future if your facility design is changed or if the NRC criteria relating to this subject is modified before the integrated assessment is complete.
Sincerely, Dennis M. Cr'stchfield, Chief Operating Reactors Branch #5 Division of Licensing cc: See next page N.h1 a:d i
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OFFICIAL RECORD COPY
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Mr. James A. Kay cc Mr. James E. Tribble, President Ycnkee Atomic Electric Company 25 Research Drive h'estborcugh, Massachusetts 01581 Greenfield Community College 1 College Orive Greenfield, Massachusetts 01301 Chairman Board of Selectmen Town of Rowe Rowe, Massachusetts 01367 Energy Facilities Siting Council 14th Floor One Ashburton Place Boston, Massachusetts 02108 U. 5. Environmental Protection Agency Region I Office ATTN:
EIS COORDINATOR JFK Federal Buildir.g Boston, Massachusetts 02203 Resicent Inspector Yankee Rowe Nuclear Power Station c/o U.S. NRC P:st Office Box 28
' cnroe Bridge, Massachusetts 01350
.