ML20002D493
| ML20002D493 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/15/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| Shared Package | |
| ML20002D494 | List: |
| References | |
| TASK-02-02.A, TASK-2-2.A, TASK-RR LSO5-80-12-037, LSO5-80-12-37, NUDOCS 8101210173 | |
| Download: ML20002D493 (7) | |
Text
.
~ h,, I,
"' E amneg;
-f N -
s e
a y
8, UNITED STATES y
g NUCLEAR REGULATORY COMMISSION
. l WASHINGTON, D. C. 20555
\\......o#
DEC 15 ISSO Decket No. 50-245 r-LS05-80-12-037 fis......
.,...'7(
Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Northeast Nuclear Energy Company P. O. Box 270 c.
Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
MILLSTONE 1 - SEP TOPIC II-2.A The SEP review of Topic II-2.A, " Severe weather Phenomena" has been a
comoleted. Enclosure 1 is the staff's safety evaluation (SE) foF the a
Millstone l site. The review was done in conformance with Standard Review Plan 2.3.1 and covers extreme temperatures, lightning strikes, snow and ice loads and wind and tornado loadings. The wind and tornado loadings analysis was performed by the Texas Tech. University, Institute for Disaster Research. Enclosure 2 is the Texas Tech. report. Please inform us if your as-built facility differs from the licensing basis assumed in our assessment within 30 days of receipt of this letter.
You will note that the SE identifies a design basis tornado with a probability of 10-7 per year and is consistent with a Regulatory Guide 1.76 design basis tornado. The staff intends to evaluate the structural characteristics of specific structures, systems and ccmponents imoortant to safety to deter nine their ability to withstand the severe weather loadings. The plant design parameters will then be e,ompared to the probability of occurrence of the wind as a part of our structural evaluation. This comparison will be used to evaluate the necessity of design changes.
Sincerely, Jg. /
Dennis M. Crutchfield, Chi Operating Reactors Branch #5 Division of Licensing
Enclosures:
As stated cc w/ enclosures:
See next page l
l k
l 8101210g"73
Mr. W. G. Counsil MILESTONE NUCLEAR POWER STATION, UNIT NO. 1 DCCKET NO. 50-245 cc William H. Cuddy, Esquire Connecticut Energy Agency Day, Berry & Howard ATTN: Assistant Director Counselors at Law Research and Policy One Constitution Plaza Development Hartford, Connecticut 06103 Department of Planning and Energy Policy Natural Resources Defense Council 20 Grand Street 917 15th Street, N. W.
Hartford, Connecticut 06106 Washington, D. C.
20005 Director, Technical Assessment Division Northeast Nuclear Energy Cocpany Office of Radiation Programs ATTN: Superintendent (AW-459)
Millstone Plant U. S. Environmental Protection P. O. Box 128 Agency Waterford, Connecticut 06385 Crystal Mall #2 Arlington, Virginia 20460 Mr. James R. Himmelwright Northeast Utilities Service Company U. S. Environmental Protection P. O. Box 270 Agency Hartford, Connecticut 06101 Region 1 Office ATTN: EIS COORDINATOR Resident Inspector JFK Federal Building c/o U. S. NRC Boston, Massachusetts 02203 P. O. Box Drawer KK Niantic, Connecticut 06357 Waterford Public Library Rope Ferry Road, Route 156 Waterford, Connecticut 06385 First Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385 John F. Opeka Systens Superintendent Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 l
i
ENCLOSURE 1 1
I Systematic Evaluation Program Meteorology Millstone Nuclear Station Unit 1 Topic II-2. AMevere-Weather Phenomena Extreme meteorological conditions and severe weather phenomena in the Millstone site region were examined to determine if safety-related structures, systems, and components are designed to function under all severe weather conditions.
Discussed below are the severe weather phenomena which could adversely affect the Millstone site and which should be examined relative to the current design.
Normal daily temperatures range from a minimum of 20 degrees Fahrenheit in January to a maximum of 80 degrees Fahrenheit in July. Measured extreme temperatures for the site region are 100 degrees Fahrenheit which occurred in July 1966 and -3 degrees Fahrenheit which occurred in January 1968.
The extreme maximum and minimum temperatures appropriate at the Millstone site for general plant design (f.e., HVAC systems) are 89 degrees Fahrenheit (equalled or exceeded 1% of the time) and zero degrees Fahrenheit (equalled or exceeded 99% of the time).
Thunderstorms occur an average of 25 days per year'in the site region.
Based on the annual number of thunderstorm days, the calculated annual flash density of ground Ifghtning strik.es is three flashes per square l
1
kilo eter. A structure with the approximate di:ensions of the Millstone Unit I reactor building can be expected to be subjected, on the average, to one strike every nine years.
The design wind speed (defined as the " fastest-mile" wind speed at a height of 30 feet acove ground level with a return period of 100 years) acceptable for the site region is 95 miles per hour. On the average, hail stores occur about one day annually, and free:ing rain occurs approximately four days per year. The maximum radial thickne's of ice s
expected in the site region is about 0.75 inch.
Mean annual 2nowf all in the site region is approximately 30 inches with a normal winter precipitation snow load on a flat surface of about 35 pounds per square foot. The maximum monthly snowf all occurred in February 1934 and totaled 47 inches. The maximum snewf all from a single storm totaled 17.7 inches. The maximum measured snow depth on the ground for the site region is 17.7 inches.
Based on the 100-year recurrence accumulated ground snowpack and probable maximum winter precipitation for the site region, the extreme winter precipitation snow load on a flat surface is about 115 pounds per square foot.
Tornadoes have been repcrted 90 times during the period 1950-1977 within an approximate 60-mile radius from the Millstone site, excluding the water area over the Atlantic Ocean. On the average, three tornadoes can be expected to I
occur in the vicinity of the Millstone site every year.
9 The tornado wind analysis done especially for the Millstone site and described in the October 17, 1979 memo (Hulman to Crutchfield) determined the 10-7 probability tornado to have a windspeed of 290 miles per hour at the upper 95 percent confidence interval. This value would appear to be appropriate for the design basis tornado that might occur in the Millstone area, although the site is situated in the Regulatory Guide 1.76 Region I having a design windspeed of 360 miles per hour. The analysis of this tornado windspeed was based upon observations of tornadoes within the land portion of the 3x3 degree area encompassing the site.
\\
, References U.S. Department of Cectnerce, NOAA, " Climates of the States," Vol.1, 1974.
U.S. Department of Coninerce, ' Climatic Atlas of the United States,"
l June 1968.
t U.S. Department of Comerce, NOAA, " Climates of the United States,"
1973.
U.S. Department of Comerce, NOAA, " Local Climatological Data,"
New Haven and Hartford, Connecticut,1976.
H. C. S. Thom, "New Distributions of Extreme Winds in the United States,"
Journal of the Structural Division, ASCE, Vol. 94, No. ST7, July 1968.
"American National Standard Building Code Requirements for Minimum Design Loads in Buildings and Other Stnictures," ANSI, A58.1-1972.
" Seasonal Variation of the Probable Maxinum Precipitaticn East of the 105th Meridian for Areas from 10 to 1,000 Souare Miles and Durations of 6,12, 24, and 48 Hours," Hydrometeorological Report No. 33, Washington, D. C., April 1956.
James A. Ruffner and Frank E. Baier, "The Weather Almanac," Gale Research Conpany,1974.
David M. Ludlum, " Weather Record Book," Weatherwise, Inc.,1973.
J. L. Marshall, " Lightning Protection," John Wiley and Sons, New York, 1973.
"ASHRAE Handbook of Fundamentals," American Society of Heating, Refrigeration and Air Conditioning Engineers, Inc., New York 1976.
Paul Tattleman and Irving I. Gringorten, " Estimated Glaze Ice and Wind Loads at the Earth's Surface for the Contiguous United States,"
Air Force Cambridge Research Laboratories, October 1973.
U.S. Housing and Home Finance Agency, " Snow Load Studies," Housing Research Paper No.19, May 1952.
U.S. Naval Weather Service, "World-Wide Airfield Summaries," Vol. VIII, United States of America, Part 4,1969.
Memo from Harold R. Denton (Assistant Director for Site Safety, Division of Technical Review, NRR) to R. R. Maccary (Assistant Director for
. Engineering, Division of Technical Review, NRR) dated March 24, 1975,
Subject:
Site Analysis Branch Position - Winter Precipitation Loads.
Memo from Jerry Harbour (Chief, Site Safety Research Branch, Division of Reactor Safety Research, RES) to L. G. Hulman (Chief, Hydrology-Meteorology Branch, Division of Site Safety and Environmental Analysis, NRR) dated August 14, 1978,
Subject:
Tornado Frequency Data for SEP Revi ew.
Regulatory Guide 1.76 " Design Basis Tornado for Nuclear Power Plants,"
U.S. Nuclear Regulatory Consission, Washington, D.C.
WASH-1300, " Technical Basis for Interim Regional Tornado Criteria,'
O.S. Atomic Energy Commission, May 1974.
H. C. S. Thom, " Tornado Probabilities," Monthly Weather Review, October-December 1963, pp. 730-736.
.