ML20154L314
| ML20154L314 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 09/17/1988 |
| From: | Dante Johnson PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20154K393 | List: |
| References | |
| OL-1, NUDOCS 8809260142 | |
| Download: ML20154L314 (27) | |
Text
.- ________ __ _
September 17, 1988 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION before the ATOMIC SAFETY AND LICENSING BOARD
)
In the Matter of )
)
PUBLIC SERVICE COMPANY OF ) Docket Nos. 50-443-OL-1 NEW RAMPSHIRE, et al. ) 50-444-OL-1
) (On-Site Emergency (Seabrook Station, Units 1 and 2) ) Planning and Safety
) Issues)
)
)
AFFIDAVIT OF DONALD E. JOHNSON I, Donald E. Johnson, being on oath, depose and say as follows:
- 1. I am a senior Mechanical Engineer for Yankee Atomic Electric company (YAEC) in Framingham, Massachusetts. Since March of 1988 I have had the responsibility for specific structural design aspects of the VANS vehicle (i.e., crane-truck assembly, siren support and supports for crane boom and electrical cabinets / panels) for the Massachusetts Public Alert and Notification System. A statement of my professional qualifications is attached hereto and marked "A".
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- 2. The purpose of this affidavit is to address allegations in contention Bases A.4 and A.6 regarding the Applicants' VANS vehicles. The allegations I address aret (1) the weight distribution with the siren fully extended will cause the equipment to f all and/or the lif ting mechanism to band or break under heavy wind or precipitation conditions (Basis A.4); (2) the telescopic crane will not reliably lift the siren to its fully extended position because of the weight of the siren and the capacity of the crane (Basis A.4); and (3) that snowy or icy weather conditions will impede extension of the sirens to their operational position (Basis A.6].
- 3. The VANS vehicle design is comprised mainly of a telescoping hydraulic crane mounted on a commercial grade truck. The telescoping crane is a with minor modifications. The crane boom consists of three sections (one fixed and two sections telescope out). The truck is a its specifications satisfy the National crane requirements. The VANS vehicle is stabilized by two sets of A-frame outriggers. One set is integral to the crane unit and provides a 15-foot stability stance. The other set, located behind the rear wheels, is securely mounted to the truck chassis and provides a 10-foot stability stance.
- 4. At each acoustic location, the following steps are taken by the truck driver regarding truck stability and lifting the siren package Deploy front and rear A-frame outriggers to stabilize and level vehicle; Raise the crane boom and siren package from the stored position to the 80' position (ima2, 80' from the horizontal). During this raising of the boom, the two outer sections are fully retractedt While at the 80' position, extend the two outer sections until all boom sections are extended.
- 5. When the first boom section is fully raised to the 80' position, the height of the crane boom above the ground is approximately 29 feet. When all boom sections are fully extended, at the 80' position, the height of the crane boom I above the ground is approximately 56 feet. These correspond l to center-line elevations of the sirens above the ground of approximately 25 feet and 51 feet respectively.
Basis A. 4: Adequacy of VANS Vehicles
- 6. As discussed in the following paragraphs, when the crane is fully extended, the equipment will not fall nor the lifting mechanism fail under heavy wind or precipitations conditions. In regard to the lifting mechanism, displacement i or bending of the boom is not failure. Bending is a normal i phenomena associated with the mechanical properties of structural materials. Structural failuro is, generally I
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speaking, when the stresses developed by the loads imposed exceed the allowable stress values specified in governing industry standards or codes.
- 7. Two analyses were performed under my direction to demonstrate that under environmental loading conditions the VANS vehicle will remain stable, the hydraulic crane when fully extended will not fail structurally, and the operability of the crane will not be affected. One analysis, performed at YAEC, evaluated the following three environmental conditions to determine which would be the governing design loading conditions (1) high speed winds (gale force / violent storm); (2) ici and wind; and (3) snow and wind. The results of this analysis, i.e., the load imposed by the governing environmental loading condition, were provided to who performed the second analysis, the structural analysis of the VANS vehicle.
- 8. In order to determine what high wind speed conditions should be considered in the design cf the VANS vehicle, I requested the YAEC Environmental Sciences Group to determine various f astest-mile wi',td speeds and the associated probability that these wind speeds would not be exceeded over a randon one-hour period, a one-day period and a three-day period (see Affidavit of George A. Harper at 11 3-9). From this information, I concluded that the design fastest-mile continuous windspeed of 51 mph should be used, which would correspond to a probability of about 99.4% that this wind 4
speed would not be exceeded in any random three-day period.
In addition, for purposes of establishing the VANS vehicle wind design margin (i.e., the additional wind capacity), I also decided to have analyze a second fastest-mile continuous windspeed of 60 mph, which would correspond to a probability of about 99.8% that this wind speed would not be exceeded in any random three-day period.
- 9. In order to determine the governing ice and wind loading condition, I requested the YAEC Cnvironmental Sciences Group to determine the ice and wind loading combinaticn which would correspond to a probability of about 99.8% that the loading combination would not be exceeded in a random three-day period (see Affidavit of George A. Harper at 11 10-13). This probability of non-exceedence is consistunt with the probabilities on non-exceedence for the high speed wind conditions discussed above in paragraph 8. From this review, I obtained the following loading information ice load 0.6 inches (or 3 psf) with an accompanying wind gust of 45 mph.
- 10. As provided in paragraph 8 above, two continuous high speed wind conditions were to be considered in the analysis. In accordance with industry practices for designing structures, a dynamic loading factor was used to account for wind gusts. Accordingly, the two wind speed conditions analyzed were (1) a continuous design wind speed of 51 eph with wind gust effects up to 61 eph and (2) a l
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centinuous wind speed of 60 mph with wind gust effects up to 72 mph. These wind speeds were converted to wind forces using the accepted industry standerd American National Standards Institute AS8.1 "Minimum Diasign Loads on Building and Other Structures."
- 11. The ice and wind loads of 0.6 inches (or 3 psf) and 45 mph wind gusts warm applied to the siren package and the crane boom when the crane is fully extended. The calculated total weight of ice is approximately 1,100 pounds. The gravity loads (i.e. deadweight and ice) are supported by the crane's hydraulic system and the wind loads are supported by the crane boom's box section design. It should be recognized that any ice on the truck would increase the vehicle's counterweight and thereby increases the vehicle's overall stability.
- 12. A snow load of 24 pounds per square foot (represents 4.6 inches of water) was considered which represents the worst 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> storm for a 100 year period (see FSAR Section 2.3.1.2, excerpt attached and marked "B"). The wind speed considered in conjunction with this snow load is the same wind speed of 45 mph considered in the ice loading condition discussed above in paragraph 10. The snow and wind load is applied to the siren package and the crane boom when the crane is fully extended. The calculated total weight of the snow is approximately 300 pounds. The gravity loads I (i.e., deadweight and snow) are supported by the crane's I
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Fcle" lic system and the wind loads are supported by the t r i r. Loom's box section design. It should be recognized cnat the snow load on the truck would increase the vehicle's counterweight and thereby increases the vehicle's overall stability. For any appreciable wind speed the snow load will become negligible. ;
- 13. A revi9w of the three loading conditions discussed in paragraphs 10, 11 and 12 above concluded that the high speed wind load conditions would be the governing loading condition for the design of the VANS vehicle truck-crant combination. Design forces developed for this condition are l considerably higher than the forces developed for the load conditions discussed in paragraphs 11 and 12.
- 14. As indicated above in paragraph 7, the forces 1
developed for the high speed wind conditions were provided to to be used in the detailed analysis of a mounted to a truck to determine the crane's adequacy to lift and support the siren package for the wind loads.
- 5.
. The wind loads were applied to the siren package t
and the crane boom when the crane is fully extended. Both wind loading conditions (i.e., 51 mph with 61 mph gusts and 60 mph with 72 mph gusts) were analyzed. The gust wind loads were treated as steady-state (i.e., constant) wind loads in r
the analysis. In addition, the code provisions to increase allowable stresses for gust wind 1
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conditions were not used. The wind was applied perpendicular to the boom's axis (weakest boom design properties) with the siren facing into the wind (the largest wind sail area). In order to assure that the crane design would be well within code allowables, some minor modifications to the standard designs of the turret and the boom foot pin were made.
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- 16. Based on my review of the analysis, l 1
I ccncluded that the VANS vehicle truck-crane combination will raise and support the siren package in the raised r position under the wind loads described in paragraph 15 supra. j
- 17. In addition to the analysis described above, early I i
during the design concept phase of the VANS vehicle, a wind f pull test was performed on a I hydraulic crane, which is an earlier version of the I crane used in ths VANS vehicle, The purpose of t
this test was to determine the feasibility of the truck-crane !
i combination to withstand projected high speed winds on the !
order of 51 mph. No Jtructural or stability deficiencies were observed during and af ter the pull test. 7.2 such, this testing provides additional assura.tce that the VANS vehicle will not fail when nubjected to high speed wind conditions.
- 18. As discussed in the following paragraph, the siren support, which supports the siren package off the crane boom tip has also been designed to withstand the loads luposed by I
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i environmental conditions (e.g. wind, ice and wind, snow and wind) and therefore will not fail structurally.
- 19. An analysis was performed under my direction to !
demot. strate the adequacy of the siren support when subjected to the design wind 1 cad conditions which govern the structural design of the siron support. The results of this i
snalyeis demonstrate that, for both design wird conditions, the applied stresses on the siren support components were below code allowable stress limits. As discussed in paragraph 15 above, the gust wind loads were treated as 1
steady-state (i.e., constant) wind loads and the code provisions to increase allowable stresses for gust wind conditions were not used.
. 20. As provided in the following paragraphs, the crane '
has sufficient capacity to lift the siren package undet varying weather conditions.
- 21. The calculated weight of the siren package (i.e.,
dual sirans, rotor, support and electrical cables) is approximately 1400 pounds. The calculated total weight of ice when the crane is in the stored position is approximately 750 pounds. The combined weight of the ice load and the siren pacP. age is approximately 2150 pounds. The calculated total weight of snow when the crane is in the stored position is approximately 1000 pounds. The conhined weight of the snow load and the siren package is approximately 2400 pounds. )
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Based on this, the maximum design load the crane could be expected to lift is approximately 2400 pounds. l
- 22. As described in paragraph 4, this load will be 6 lifted with the outer two boom sections fully retracted, from l the stored position, to the 80' position. The hydraulic 6
crane's rated capacity to lift this 1cid trou the stored position on the truck is 5200 pounds. As tiso described in l paragraph 4, this load is next lifted to its maxiuum height j
by means of extending the outer two boom sections. The rated capacity of the hydraulic crane when fully extended at the 00' position is 6400 pounds. (See letter attached and marked "c".) Therefore, the crane boom has sufficient capacity to I
lift the siren package plus the design ice or snow loads from
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its stored position to the 80' fully extended position.
Basis A-6: Sire. Operation in Snowy, Icy and cold Weather conditions
- 23. As providwd in the following paragraphs, the 1
extension of the sirens to their operational position will not be impeded by snowy or icy weather conditions.
- 24. From the discussions above in paragraphs 21-23, the maximum design load is considerably less than th6 rated capacity of the crane. It necessarily follows that this excess capacity of the crane is available to overcome the l
! effects of any snow or ice that may have accumulated on the Crane boom.
l l 25. Furthermore, the rated capacity of the crane with just one of the outer boom sections extended at the 80' M
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position is 10,S00 pounds, which is over four times greater '
than the maximum design load. Since extension of the two outer sections occurs after the first boom section has been j raised to the 80' position, a forc0 of at least 9,000 pounds is available to overcome the effects of accumulated snow att ice.
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- 26. Based on the excess capacities available, extension of the crane boom will not be impeded by accumulation of snow l or ice.
l 27. Based on the foregoing paragraphs, I have concluded that:
(a) the .tren package will not fall when crane is l raised and y extended; (b) the lifting mechanism will not fail l structurally because of environmental loading conditions, such as wind, snow or icer I (c) there will be no stability problems for the design wind loading conditionst r
(d) The siren support will not tail structurally ;
because of environmental loading conditions such as '
wind, snew or icer
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(e) the crane has sufficient capacity to lift the siren package, even when coated with ice equivalent to a weight of 1100 pounds, from its stored position tu th-l t I
fully extended 80' position l
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(f) the excess crane capacity can handle accumulation of ice or snow without impeding the operation of the crane.
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l Donald E. Johnson September ,_,, 1988 The above-subscribed Donald E. Johnson appeared before me and made oath that he had read the foregoing affidavit and that the stat.ements set forth therein are true to the best of his knowledge.
Before me,
-* .- . : // , /,
Notat"y Public '
My Commission Expires:
MARY T. BATTAOLIA. Notary Public My Wssion Espres Spenw 16, 1994 i
l I -_ ., _. ._ __
Johnson Attachment A, 1 of 1 DONALD E. JOHNSON P.E. I I
Senior Meenanical Engineer Education B.S. Civil Engineering, Northwastern University, Boston, Massachusetts, 1974 M.S. Civil Engineering, Northeastern University, Boston, 1:assachusetts, 1979 Professional Membershins American S J'-ty of Civil Engineers American Ict .ute of Steel Construction American Concrete Institute Ernerience Mr. Johnson joined Yankee Atomic Electric Company in October 1983 as a Senior Engineer in the Mechanical Group of the Seabrook Project. He is a Registered Professional Engineer in the State of Massachusetts. He has sixteen years of experience in the structural design and analysis of building structures and support structures for building systems (piping, KVAC and electrical).
Previous to working at Yankee Atomic, Mr. Johnson workhd for 5 years at CYGNA Energy Services, an engineering consulting firm in Boston and 6 years at Stoaa & Webster Engineering Corporation, an architectual/enaineering firm also in Boston.
Johnson Attachment B, 1 of 12
_ SB 1 & 2 Amendment 53 FSAR August 1984 force. The site, therefore, may be af fected by a hurricane, including associated heavy rainfall, high winds and high tides-,
2.3.1.2 Regi;onal Meteorological Conditions for Design and Operating Bases
). Regional Climatological Data Stations Figure 2.3-1 shows the locations of the Seabrook site and weather stations in the general area from which climatological data were obtained.
The general location and type of data available from these weather stations are as follows:
Portland International Jetport National Weather Service Of fice
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CPortl'and NWS). This station Is~ located about 59 miles north-northeast of~the site just inland f rom the Atlan:ic Ocean and is a primary source of regional meteorological data for the site. The Portland NWS collects complete meteorological data on a continuous basis.
Boston Lojan International Airport National Weather Service Office Most'6n~NWS T 'This station is located about 38 miles south-southwest if the site on a land fill that extends into Boston Harbor, which is part of the Atlantic Ocean. It is a primary source of regional meteorological data on a continuous basis.
Concord Municipal Airport National Weather Service Office (Concord NWS). This station is located about 40 miles west-northwest of the site. The Concord NWS collects complete meteorological data on a continuous basis.
Pease Air Force Base Air Weather Service Station (Pease AFB).
This station is located abcut 13 miles north-northeast of the site in Fortsmouth.
Instrumentation information regarding the abeve of fsite NWS and military weather stations is presented in Table 2.3-1.
Data from the following cooperative weather stations was also utill ed:
Port smouth, New Hampshire. This station is located about 13 miles north-northeast of the site and is maintained by the Department of Public Works, a cooperative weather observer.
Rockport Massachusetts National Vesther Service Climatological Station. This station is located about 27 miles southeast of the site. This station collects daily maximum and minimum temperature and precipitation data.
Sanford Maine National Weather Service C1!matological Station.
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This station is located approximately 35 miles north of the site.
Daily maximum and minimum tesperature and precipitation data are recorded at this station.
2.3-2
Johnson Attach:nent B, 2 of 12 S81&2 Amendment $3 FSAR Augu s t- 1984 O
Creenland New Hampshire National Weather Service Climatological station. This station is located about 7 miles north of the site and collects daily maximum and minimum temperature and precipitation data.
- b. Regional Severe Weather Climatology
- 1. ,Hu,r r ic ane s Atlantic hurricanes are most cournon during late summer and early fall. During the period 1871-1977, approximately 43 tropical cyclones passed within 100 nautical siles (115 statute t.;ilee) of the site. Of these, 22 storms were classified as hurricanes, and oc'y 3 retained full hurricane state within 100 nautical miles of the site (Reference 2).
- 2. bl a
Jchnson Attachment 3, 3 of 12 Si$I A 7 Amendment 56 FSAlt November 1985 Tropical storma ur hurricanes that reach the New England area unually pnNm northward wews of the site or on a northeast track South of the site. Since . to date, the only hurricanes or tropical storms to reach the Seabrook area h*1ve had to travel a substantial distnnce overland, the potential impact of such scoras is significantly reduced. Potential impact is usually anfined to the effects of high tides and heavy rainfall (Reference 1).
- 2. Tornadoes and Waterspouts Tornadoes have occurred in all the New England States. The mean annual number of tornadoes per 10,000 square miles for the period 1953-1976 in New Hampshire, Maine and Massachusetts are 2.5, 0.8 and 5.2, respectively (Reference 3).
A National Severe Storms Forecast Center (NSSFC) listing of tornadoes within a 50 nautical mile radius of the site indicates that 69 tornadoes occurred during the period 1950 l m
thsough 1977, with a mean path area of 0.124 square miles (Reference 4).
Thom (Reference 5) has developed a procedure for estimating the probability of a tornado striking any point from an analysis of mean path length and width and the frequency of tornado occurrence in the area. Applying Thom's procedure to the NSSFC data gives an annual probability of a tornado striking any point within 50 miles of the site of 7.8 x 10-5 with a mean recurrence interval of about 12,900 years. (The calculation excluded the water area within the area of interest.)
In spite of the low probability of a tornado occurrence, seismic Category I structures at the Seabrook site, except for the refueling water tank spray additive tank enclosure and cooling tower, are designed to withstand the "Standard Tornado" as described in NRC Regulatory Guide 1.76 (Reference 6). This design basis tornado has the following characteristics:
(a) A maximum wind speed of 360 miles per hour (b) A rotational speed of 290 miles per hour (c) A maximum translational speed of 70 miles per hour (d) A minimum translational speed of 5 miles per hour (e) A radius of maximum rotational speed of 150 feet (f) A pressure drop of 3.0 pounds per square inch (g) A rate of pressure drop of 2.0 pounde per square inch per second 2.3-3
Johnson Attachment B, 4 of 12 S81&2 Amendment 56 FSAA Nove:sber 1985 ~
In an analyses of waterspout occurrences using Storm Daly, Reports (1959-1973) and ship lox report s (1850-1940), a total of 14 waterspouts were reported off the coast between Boston and Portsmouth of which 3 were considered to have caused coastal
, damage (Reference 7). A waterspout coming ashore and striking the site would not have a destructive effect greater than that of a tornado. This is based on the wind speed of a waterspout not being greater than Lt'e design basis tornado of Regulatory Guide 1.76. L'ith exactly the same wind speeds. it is concluded that a waterspout would be less destructive than a tornado as it would contain less solid debris than a tornado that had been traveling overland.
(3) Thunderstorms, Lightning ar' Hail Table 2.'3-1a shows the mean number of days with thunderstorms l for various weather stations in the general Seabrook area. O Thunderstorms have occurred during every month of the year, with the maximum during the summer. Pease AFB data can be considered most representative of the Seabrook site, showing a thunderstorn frequency of about 1^ ,er year with a maximum monthly mean of about 5 in July (Reference 11).
Using the thunderstorm frequencies shown in Table 2.3-la for .
Pease AFB and statistics relating to thunderstorm occurrence and to the probability of cloud-to ground lightning as pre- -
sented by Viemeister (Reference 12), estimrtes of the frequency of occurrence of cloud-to ground lightning were derived for g the site on a seasonal and annut s basis for objects extending to heights of 50, 100, 200 and M feet above grade. These results are provided in Table 2.3-2.
Marshall (Reference 12a) presents an alternative methodology for estimating lightning strike frequencies which includes consideration of the attractive area of structures. Marshall's method consists of determining the number of lightning flashes
- o earth per year per km2 and then defining an area over which the structure can be expected to attract a lightning strike.
Assuming that there are 0.135 flashes to earth per thunderstorm days per kre2 near the Seabrook site (Reference 12a) and that the Seabrook site experiences 19 thunderstorm days per year (Pease AFB data, Table 2.3-1s), thera are approximately 2.57 flashes to earth per year per km2 around the Seabrook site %
ares. If the length of a structure is I., its width W, and its height H, Marshall defines the total attractive area A of that structure for lightning flashes with a current magnitude of 50% of all lightning flashes as:
A = LW + 4H (L + W) + 12.57 H2 The following building complex dimensions wre used to con se rvatively e stim.a te the a ttrac tive areas:
n 2.3-4
Johnson Attach nent B, 5 of 12 SB 1 & 2 Amendme nt 56 FSAR NoveLber 1985 I
's - Unit #1: L = 200m, W = 120s Defined roughly by a rectangle outlined by the
, turbine building, administrative building, fuel storage building, and containment structure.
H = 56a De fined by the height of the primary vent stack.
A = 0.135 km2 Unic #2: L = 200m, W = 90s Defined roughly by a rectangle outlined by the turbine building, control building, tank farm areas, primary auxiliary building, fuel storage building, and con-tainaant structure.
H = 56s Defined by the height of the primary vent stack.
A = 0.122 kt:2 Lightning strike frequencies computed using Marshall's methodology are given as 0.35 and 0.31 flashes / year, l respectively, for both Unit I and Unit 2.
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Table 2.3-3 lists the total number of days with hail ovic a 40 year period for Boston, Portland and Concord. The data indicate tho:, on the average, the site should expect less than one day per year with hail (Reference 13). Hailstorms in the Seabrook area are seldom severe, although large hail has been reported. During the 13 year period between 1955 and 1967, an average of 0.2, 0.6 and 1.3 storms per year with hailstones 1.5 inches in diameter or larger have been reported for New Hampshire, Maine and Massachusetts, respec-tively (Reference 14).
(4) S t ro n,g,W ind s Table 2.3-4 lists the f astest mile wind speeds recorded at Boston, Portland and Concord. The data indicate that wind speeds over 40 mph can occur during any month of the year.
During the winter these speeds are normally caused by north-easters that move up along the coast. During the warmer months, high winds are normally associated with thunderstorms and squall lines that pass through the area. Hurricanes 2.3-4a <
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so 4 'a . Johnson Attachment B, 6 of 12 FSAR
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could produce high wind speeds during che late summer and ~
early fall.
Thoe (Reference 15) plotted isotachs of annual extreme-mile wind speeds at 30 feet above ground for several recurrence intervals across the United States. Table 2.3-5 dhowa the annual extreme-mile wind spe(de derived from Reference 15 for the Seabrook site for four recurrence inte vals and indi -
cates a sustained 95 mph wind speed can be expected nrich a 100 year recurrence interval. Other studies (References 15a,19), which also plottud f ootachs for fastast mile of wind at 30 feet above ground across the United States, Indicate a fastest alle of wind for a 100 year probable period of recucrence cf 110 mph and 100 mph, respectively, fcr the Seabrook site.
The more con 1ervative value of 110 mph is used as the 100 year period of occurrence design wind velocity for seismic Category I structures at 30 .' set above ground. The vertical wind velocity profile and the appropriate gust factor used for seismic Category I structure wind loading analyses are discussed in Section 3.3.1.
(5) Snowload -
Tb6 American National Standards Institute, Inc. (ANSI) gives the 100 year recurrence interval snow load on the ground in the Seabrook area as 42 pounds per square foot (Reference 19).
The maximum 24-hour precipitation amount observed in the site during the snow season (November through April) is 5.4 inches of water, as shown in Table 2.3-17. From this value, a conservative 48-hour probable maximum snowfall is defined as having twice the water content of the maximum 24-hour scorn, or 10.8 inches. As required by Regulatory cuide 1.70 (Reference 20), the Probable Maximum Winter Pescipi-tation was determined, which resultod in a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> precipitation o f 16.1 inches (Reference 21). Assuming this amount of pre-cipitation fell on top of the 100 year recurrence interval snot 3ck of 42 pef, as given by ANSI, it would result in a compacted snow load of 125.7 psf. This is considered an "unusual" load condition as described in Chapter 2. Roof loadinc for safety-related structures dae to precipitation, including ice, snow and rain, are discussed in Subsection 2.4.2.3. ,
The February 6-4, 1978 anowstors which struck New England was one of the most intense, pecsistent, severe winter storms on record (?wforence 22). The hichest melted pr cipitation associated with the storm was 4.55 inches reported at Pembroke, Massachusette (Reference 16). The New England climatologist, Robert E. Lautzenheiser, had previously stated that the February 03-28, 1969 anowet6rs was probably the worst storm in 100 years. it.e highest melted precipitation associated with 2.3-5
Johnson Attach:mnt B, 7 of 12 SB 1 & 2 FSAR l 1
the storm was 4.62 inches reported at Rockport, Massachusetts.
Ine 4.62 inch value is equivalent to a snowfall load of 24 paf. When this is cea5ined with the 100 year probable maximum snowpack of 42 psi, it results in a total snow load on the ground of 66 psf.
(6) Ice Storms Freezing precipitation, or glaze ice, dets occur in the Seabrook area. Data for freezing rain at Portsmouth (Reference 23) are presented in Table 2.3-6. Mapped data for the period 1928 to 1937 indicates that the site averages 2-3 ice storms per year. For the nine year period of study, about 12 storr:
- occurred resulting in ice with a thickness of 0.25 inch or more, of which about 6 storms had ice of 0.5 inch or more (Reference 24). More recent mapped data foc the period of 1950 to 1969 (Reference 25), indicates that the site averages about 8 ice storms per year.
(7) High Air Pollution Potential and Mixtng Heights The Seabrook site is not in an area of frequent air pollution episodes or alerts. A study of synoptic weather map analysis
, for 1936 through 1975 shows high pressure stagnation conditions lasting four days or more over the site occurring 12 times 'g with an average of 4.4 stagnation days per case (Reference 26).
Holzworth (Reference 27) analyzed five years of data to determine
, occurrences in the United States of episodes of meteorological conditions unfavorable for atmospheric dispersion. Holzworth indicated episodes of high air pollution potential as periods with low mixing depth and light winds. A summary of the Holzworth data as it applies to the site appears in Table 2.3-7. The data indicate that prolonged periods with a combination t
of low wind speed and low mixing height are uncommon in the site area.
Holzworth (Reference 27) also plotted isopleths of mean seasonal and annual morning and af ternoon mixing heights across the United States from the same five years of data. For the Seabrook site, the seasonal and annual values of the mean daily mixing heights occurred as follows:
Mean Daily Mixing Heights Season Morninj Afternoon Spring 710 a 1400 m Stamer 450 m 1400 m Autumn 590 m 1100 m Winter 700 m 900 m .- )
Annual 600 m 1200 m '
2.3-6
Johnson Attachment B, 8 of 12 SB 1 & 2 FSAll -
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r The above data represent estimates of the average depth of vigoro'is vertical mixing, which give an indication of the vertical depth of atmosphere available for mixing and disper-sion of effluents. .
(8) Ultimate Heat Sink .
Data collected at Pease AFB for the 10 year period 1961-1970 and at Bosten NWS for the 29 year period 1945-1973 were used to evaluate the performance of the Ultimate Heat Sink with respect to maximim evaporativa and drif t loss, and minimum water cooling.
Maximum evaporative and drif t loss vs: defined to occur during periods of large differences between the ambient dry bulb and wet bulb temperatures. The functioning of the ultimate heat sink cooling tower has been analysed under the condition of the maximum 30 day average hourly difference between dry bulb and wet bulb temperatures. Data from rease AFd and Boston NWS shows that the maxiom 30-day average hourly dif-ference betwaan dry bulb and wet bulb temperatures occurred as follows:
3,0,-Day Average Maximus Dry Bulb Minus Wet Bulb Dif ference
- Starting Average Average DB-WB Location Date Dry Bulb Pet Bulb Difference Pease AFB 6/19/64 64.70F 55.00F 9.70F Boston NWS 7/28/57 73.90F 63.40F 10.50F Minimum heat transfer to the atmosphere was defined to occur during periods of high wet bulb temperature. For the purpose of the uti:imate heat sink coollug tower analysis, a review of meteorologicci data from Pvase AFB and Boston NWS showed tha; the maximum average wet bulb tamperature for a 24-hour and a 30-day period of record occurred as follows:
Maximw Wet Bulb Temperatures 24-Hour Average 30-Day Average
, Location Date Averste Starting Date Average Pease AFB 6/16/68 74.607 7/22/70 67.20F Boston NWS 8/17/59 75.50F 8/21/55 59.40F A review of the above seteorological data analyses led to the design parameters for the ultioate hest sink cooling tower. These design parameters include 10.50F for the tower Jry bulb minus wet bulb dif forence ana 750F for the tower wet bulb temperature (see Section 9.2.5).
2.3-7
Johnson Attach:nent B, 9 of 12 SB 1 & 2 Amendment $3 1 FSAR August 1984 '
2.3.2 Local Meteorotomy 2.3.2.1 Nermal and Extreme Values of Meteorological Parameters Monthly and annual summaries of eeteorological parameters from long-tera data stations representative of the tres are presinted in th8.s section. Suunar ie s of on-sits mete'orological data collected at Seabrook from November 1971 through March 1973 are also provided in this Section and in Appendix 2A. A new onsite meteorological tower has been erected at the same location as the old tower and became fully operational in April 1979. Data susunaries f rom this new torer for the time period April 1979 through March 1980 are presented ir. Appendix 28.
- a. Wind Wind roses for the four seasons and 12 month period (Noverth er 1971-October l972) of collected on-site data are provided in Figures 2.3-through 2.3-6, respectively. The data indicase that westerly utrough northwesterly winds predominate during most of the year. During the summer months, southwesterly through west-northwesterly, and east-southeasterly through south-scucheasterly winds are prevalent. Wind direction persistence summaries for 22.5 and 45.0 degree sectors are presented f.n Appendix 2A.
Seasonal and 1.2 month period wind roses collected onsite from the new onsite meteorological tower (April 1979-March 1980) are provided in Appendix 25. Wind direccion persistence summaries for this same period -
are also provided in Appendix 25.
- b. Temperature Tables 2.3-8 through 2.3-13 present long-term mean and extreme terperature values for a number of stations in the Seabrook area. Portsmouth data can be considered representative of long-tern Seabrook temperatures.
Monthly onsite mean and extreme temperature values for the time period April 1979 through March 1980 are presented in Appendix 28.
Extremes of temperature are uncommon due to the proximity of the site to the Atlantic Ocean. During the winter, arctic air masses passing through New England can produce low minimum temperatures, but the frequency and persistence of such extreme values along the coast is less than for stations located farther inland. During the spring and summer a seabreeze usually moderates temperatures from reaching high extremes at the site.
Detailed analyses have determined that the highest hourly temperature recorded during the period 1957 through 1981 at Pease AFB (Portsmouth, NK) was 101oF on July 1,1964 (hour 13). The hottest contiguous 24-hour period containing this temperature extended from June 30 (hour 15) through Ju'ay 1 (hour 14). The hourly temperature progression for this period is provided in Table 2.3-13A. Hourly temperature data associated with the five '
hottest and five coldest 24-hour average temperatures recorded at Pease AFB in the period 1957 through 1981 are given in Table 2.3-115.
H 2.3-8 I
Johnson Attachment B, 10 of 12
+
S81&2 Auendment 53 FSAR August 1984 -
l An additional statistical analysis (Referenes 27A) of extreme temperature data collected at nearby weather stations (Pease AFB),
climatological stations (Rockport, MA, Sanford, M1, and Creenland, ,
NH) and at the Seabrook sit = results in 100 year return period maximum and minimum hourly temperatures for the Seabrook site of 1020F and -210F, respec2ively. (These values were computed following the methodology found in NUREC/CR-1390).
Since the design of certain equipment is dependent upon the maximum and minimum temperatures averaged over time periods greater than one-hour, 100 year return period extreme temperatures for 2, 4, 8,12, and 24-hour averaging periods were also determined. These values are listed below:
100 Year Return Period Temperature (OF)
Averatina Peried Maximus Minimum 2-dour 102 -21 4-Rour 101 -21 8-Hour 99 -20 12-B7 ur 96 -19 24 Hour 89 -16
- e. Atmospheric Vatte Vapor Long-term mean monthly relative humidity statistics at Pease AFB are provided in Table 2.3-14. Onsite dew point statistics for the period April 1979 through March 1980 are provided in Appendix 28.
Joint frequency distributions of the on-site moistura deficit teve been prepared for cach stability category and wind direction.
O 2.3-8a
Johnson Attach.T.ent B, 11 of 12 SB1&2 FSAR Those data from April 1972 through March 1973 are presented in detail in Appendix 2A.
- d. Precipitation On the everage, the Seabrook area has about 129 days per year with measurable (0.01 inch or more) precipitation, as indicated in Table 2.3-15. Table 2.3-16, which shows mean monthly and annual precipitation amounts indicates that monthly preepitation is equally distributed over the year, with mean monthly amounts generally between 2.7 to 4.6 inches.
The site can expect an annual precipitation of about 43 inches.
Summer rainfall is caused primarily by thunderstorms and convectiva shower activity. Precipitation during the rest of the year generally results from the passage of low pressure systems. During the colder months of the year, intense coastal storss or northeasters move north-eastward along the New England coast, usually affecting coastal locations with heavy rain or snow and on occasin, ice storm conditions. Occasion-ally during the stasner or fall, a storm of tropical origin will cause substantial ratufall and high winds in the vicinity of the site.
Precipitacion extremes for arec stations are presented in Tables 2.3-17 <
through 2.3-20. Based on the Portsmouth data, a maximum monthly precipi-tation amount of about 14 inches and a maximum 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> precipitation amount of about 7 inches could be expected at t!.e site.
While periods of prolonged drought are not coccon, dry spells do occasion-ally occur. March 1915 and October 1924 were particularly dry, as indi-cated in Table 2.3-20.
Snow f alls in the site area as early as November and as late as April.
Mean snowfall statistics for the area. Table 2.3-21, indiutes that the site een expect an annual snowfall of about 72 inches. Ma xirr.um snowf all data are presented in Tables 2.3-22 and 2.3-23, which suggest a maximum 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> snowfall of about 22 inches and a maximum monthly snowf all of about 54 inches, based on Portsmouth data.
The ground is norus11y covered with snow from late December until well into March, although it may remain bare for several weeks during this period in a milder wir.ter. A continuous snow cover of at least one inch lasts 30 to 45 day
- in a usual winter, but continued for 87 days in tha snowy winter of 1955-1956. The average maximum snow depth is about 18-24 inches (Reference 23).
- e. Fog The proxiretty of the ocean is an important factor in fog occurrence at the site. During the spring and stsamer months, fog forms of fshore as warm, moist air flows over the relatively cold ocean water. With any persist?nt eastern component in the wind direction, the fog that of ten lies just off shore during the warmer months can reach the Sea- <
2.3-9
Johnson Attachment B, 12 of 12 SB 1 & 2 Amendmont 44 FSAR February 1982 brook site. This situation {e supported during the suureer by local heating ano a resulting seabreese.
Table 2.3-24 provides information on the mean otsober of days with heavy fog at s':troundias stations. Based on Pease AFB data, Table 2.3-25, all months of the year have a fairly consistent frequency of occurrence of fog. Although fog at Pease AFB occurs about 152 of th3 time, it is
- dense enough to restrict visibility to 1 mile or less only about 3.5%
of the time (Reference 23). Table 2.3-26 lists the mean number of hours wir' visibility less than 0.5 miles.
Statist cs on fog persistence at Portland are presented in Table i
2.3-26a for the 10-year period (1968-1977). Table 2.3-26a indicates that durations of periods of fog lasting 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> or longer can occ'Jr several times a year.
- f. Atmospheric Stability 44 Join; frequency listributions of Pasquill stability class by the tempera-ture28.
dia dif ference (delta-T) method are presented in Appendix 2A and Appen-Suessaries of atmospheric stability persistence are also provided in both Appendices. The onsite data frots the new meteorological cover indicate that frca April 1979 through March 1980 unstable, neutral, and stable conditions occurred as follows:
Frequency ofJ tability Classes '
stability C1sasification 4 3 '-150' Delta-T 43'-2 W Delta-T Unstable (A,8,C) 21.1% 12.7%
Neutral (D) 41.5% t3.at Stable (3,F.C) 37.3% 44.0%
2.3.2.2 Potencial Influence Meteorology of the Plant and Its Facilities On Local A map is presented in Figure 2.3-1 whleh shows the topography within a five-mile radius 3f the site. Maxistm elevation with distance is plottsd 'sn Figure 2.3-8 for each of 16 sectors radiating from the plant site. The heights shown in these cross sections are for the highest representative terrain a that distance in the
- sector, shown.
and not necessarily the exact height at the precise bearing and distance The immediate site area is tidal marsh with short grass, reeds and tidal channels.
$hort trees begin at the edge of the marsh as the terrain becomes slightly irreg-ular A few short ridges and hills occur within the first five sites from the site.
A map showing detaued topographic features within a 50 mile radius of the site is presented in Figure 2.3-1. The first hills and ridges of the White Mountaina of New Hampehire occur 20-75 af.les northwest, west and southwest of the site.
Milly terrain with peaks between 200 and 500 feet are found 25 to 40 miles from the site. f' The plant is not expected to cause any significant influence on the local neteorology as cooling towers or spray ponds are not planned for normal operations.
2.3-10