ML20041F470

Forwards Response to Accident Evaluation Branch 820212 451 Series Request for Addl Info.Methodology Used to Develop Estimated Frequencies of Lightning Strikes Provided

ML20041F470
Person / Time
Site:	Seabrook
Issue date:	03/12/1982
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Miraglia F Office of Nuclear Reactor Regulation
References
SBN-233, NUDOCS 8203160530
Download: ML20041F470 (24)

Text

t sEAnaOM sTAM L6:: 's Office:

IPUBLIC SERVICE Companyof NewHampshw e 1671 Worcester Road Framingham, Massachusetts 01701 (617). 872- 8100 td O' ,-,

'R . 'l March 12,1982 # M A '

6} #8 'O 4 :3 SBN-233 '_) Q T.F. B 7.1.2 9 A e

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United States Nuclear Regulatory Commission C I g hf, Washington, D. C. 20555 At tentio n : Mr. Frank J. Miraglia , Chief Licensing Branch #3 Division of Licensing Re f ere nc es : (a ) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) USNRC Let ter, dated February 12, 1982, " Request for Additional Information," F. J. Miraglia to W. C. Tallman

Subject:

Responses to 451 Series RAIs; (Accident Evaluation Branch; Meteorology Section)

Dear Sir:

We have enclosed responses to the subject RAIs, which you forwarded in Re f e re nc e ( b) .

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY JA O John DeVincentis Project Manager JDV : ALL: dad Enclosure ROOY g l

8203160530 920312 PDR ADOCK O'000443 A PDR

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• 451.10 The discussion of lightning in Section 2.3.1.2 includes estimates (2.3) of the seasonal and annual frequencies of cloud-to-ground (FSAR) lightning for objects of various heights above ground. Indicate if the methodology used to develop the estimated frequencies of lightning strikes presented in Table 2.3-2 includes consideration of the " attractive area" of the structures, rather than just height above ground. (See J. L. Marshall, Lightning Protection, 1973, for a discussion of " attractive area" for lightning strikes.) If not, provide a revision to Table 2.3-2 which is based on the " attractive area" of structures.

RESPONSE: The estimated frequencies of lightning strikes presented in SB ,

FSAR Tabic 2.3-2 were derived from Figure 50 of Viemeister (Reference 1) using Pease AFB thunderstorm day frequency of 18.9 per year. Viemeister's data show the effect of height on the likelihood of a lightning strike to an isolated tower or mast standing on level terrain and do not specifically consider the

" attractive area" of structures. Using Viemeister's data (and not specifically accounting for the attractive area of structures),

the estimated frequency of a lightning strike to the plant's highest points (the primary vent stacks at 56m AGL) is 0.72 strikes per year per stack. Viemeister does mention that the area of an object does have a bearing on how many strikes may be ,

expected, but states that the taller the building is, the less important the area consideration is.

l l

i Marshall (Reference 2) presents an alternative methodology for estimating lightning strike frequencies which includes consideration of the attractive area of structures. In order to compare results of the two methodologies, Marshall's method is used below to calculate the frequency of lightning striking the Seabrook structures with the largest attractive areas, the Unit #1 l

and Unit #2 building complexes.

I

Marshall's method consists of determining the number of lightning 2

flashes to earth per year per km 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 km2 near the Seabrook site (Reference 2,

p. 30) and that the Seabrook site experiences 18.9 thunderstorm days per year (Pease AFB data, SB FSAR Table 2.3-la), there are approximately 2.55 flashes to earth per year per km 2around the Seabrook site area. If the length of a structure is L, 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 H The following building complex dimensions were used to conservatively estimate the attractive areas:

Unit #1: L = 200m, W = 120m

> Defined roughly by a rectangle outlined by the turbine building, administritive and service building, diesel generator building, waste, process building, fuel storage building, and containment structure.

H = 56m Defined by the height of the primary vent stack.

! 2 A = 0.135 km Unit #2: L = 200m, W = 90m l

Defined roughly by a rectangle outlined by the turbine building, control building, tank farm area, primary auxiliary building, f uel storage building, and containment structure.

H = 56m Defined by the height of the primary vent stack.

I A = 0.122 km Given the above attractive zones,and_ assuming there are 2.55 flashes to earth per km2, the estimated frequencies of a lightning strike to the Unit #1 and Unit #2 building complexes are O.34 flashes per year and 0.31 flashes per year, respectively.

Although both Viemeister and Marshall differ in their approaches, both are almost within a factor of two of each other in predicting the frequency of lightning striking the Seabrook building complexes. In spite of the lack of consideration of the attractive area of structures, Viemeister's methodology predicts a higher frequency of lightning strikes. As such, Table 2.3-2 presents the more conservative estimates of lightning strikes for the Seabrook site.

References to 451.10

1. Viemeister, P. E. , The Lightning Book, MIT Press, Cambridge, MA,1972.

l l 2. Marshall, J. L. , Lightning Protection, John Wiley & Sons, New York,1973.

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l RAI 431,11  !

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a. Identley meteorological conditions (including extreme temperatures, pressure, humidity, and windspeeds) considered in the design of auxilicry systems and components (e.g., the diesel generator combustion air inl:ake and exhaust system discussed in section 9.5.8).

b. Provido the bases for the selected values (including the magnitude and duration).

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c. Comparo the selected values with severe or extrees meteorological condici.ons observed in the reston through 1981 (through January 1982 ,

l for ext:reas. minimum temperatures).

-.m , _. . . . . , m.m _~,_m. ,. mm_ m

_m _._.

d. Comparo the selected values with those presented in Section 2.3.1.2 for

- tornadoes and hurricanes, entreme winds (e.g.,100 year recurrence),' f extremo temperatr"u (100-year recurrenceg see NUREG/CR-1390,

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" Probability Estb' as of Temperature Extremas for the Contiguous t!nited states"), and other extreme conditions for atmospheric, moisture and precipi,tation. -

RESPONSES , . ,

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a. Meteorc losteal ~oonditilone- considered in:the; design,:of ausili;a~ cG;;.

etess _ ~

sad coo ponentsiffezclusive . o fittisidiese17 "10 ' .  ;

exhaust  ; systes[are

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summarissMb$1'dwfth'(eInsratoriair'.iin"ei ons>for' ' Gi"r'olEsihtdlid'  !

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the diose1' generator' air' intake'and enhaust T oystea ai,Caddriised'iEd N j l

RAI'430.130. .,

Extreet Outdoor. Temperatures '

&zimum 880F ', _.

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! Ml.nimum 0*f Relative Outdoor Busidity Mximum 100% '

• 1 Mi.nimum 101 ,

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The abovetemperatureandhumidityestrNsLwereutilisedth[tEs.,, des.ign ')

l of the RVAC systems forza11ssafety-related .'

maintal a temperature and humidity 'environi(buildingsr TlieTEVA4 systems .

ent'alwithinitbe'ibnil'd sTae . m_

'specified in FSAR Figure-3.11(3)-1;(serjidisTEnvi'riissIsnti,dinit $$57 l the out $I, . _1 g door gooditions[specified5'above

.7

F'- Q dv- @ % i % [m~W. . v(a}-.

seismic. Category I structures and certain'non-Seissio Cateson.tb n i .

structs res, as 1isted in subsection 3.8.'4.1, were designed ~ foe'tind

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velocit les as follows: -

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~~g".. '." *Q T *"T ' , [ :""" ' *-- _. ,'."' ~:~~~"'~ T n c m y ~

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iw, J AM.08 ' 80 22:03 GMT SLnuxuuA dinsawn SB 1 & 2 FSAR Severe Environmental Load A wind speed of 110 mph at 30 feet above ground for a 100 year r eturn period.

Extress Envirotusental Ioads A total maximum tornado wind velocity (translational plus r otational of 360 mph.)

Seismi : Category I structures and certain non-Seismic Category I struct< ares were designed for the following atmospheric pressure change

- accomp anying the design basis tornado

- ~ - - . m- w., , . . , _ __ ~ *

• Total pressure change due to passage of tornados 3 psi ,,  ;

E tt..of e pressure change: 2 psi per second

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The ba ses for specification of temperature extremes are actual measured b.

region al temperatura distributions for Messachusetts presented in "AS10tA C Handbook of Fundamentais Chapter 22. Table 1. page 380. 1967 Edition., The 2% percent values (Susmer) and- 97 percent values ' (Winter)

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of the distributions were used. ~

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The ba des for.tha' selection of tha humQty; range is the assumption,that

'relati re:humidifiesfatfor near 100.jpered' a.ctoccuriduring,fogWdew;fpress tion sad ia%precip~i'.:ation' which are g ,

'Rafa^tt Idicies*1'ess than 10 percent"are not!frequently observed und'erJthe observed?in'this

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climatic conditions affecting this site. . _

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P' Tha ba ses for the design' wind velocities and atmospherie pres's.ures'for seismic Category..I structures and'cartain non-Category I structures ~

(listed i_n Subsection 3.8.4.1) are discussed in Subsection 2.3.1.2.

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c. Response to be provided by May 3, 1982 {

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d. Response to be provided by May 3, 1982 9

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451.12 a. Provide a detailed description of the procedures used to (2.3) examine 10 years of data (1961-1970) f rom Pease AFB and 29 (FSAR) years of data (1945-1973) from Boston to select

. meteorological conditions for designing the ultimate heat sink.

, b. A vet bulb temperature of 75 F has apparently been considered in the design of the mechanical draft cooling tower used as the ultimate heat sink. This wet bulb temperature has been exceeded as a 24-hour average at Boston (see Page 2.3-7). Identify the duration assumed for the

' ' " design wet bulb temperature of 75 F. If the assumed " >'~~

duration is for a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or less, provide the rationale for selecting a value for a design parameter that is less than an observed condition.

RESPONSE: a. Ten years of Pease AFB hourly observations (Reference 1) and 29 years of Boston NWS hourly observations (Reference 2) were analyzed in order to evaluate the performance of the ultimate heat sink. Daily average ambient dry bulb and wet bulb temperatures were computed from the hourly observations. The consecutive 30-day period with the largest difference between the average daily dry bulb and wet bulb temperatures was then determined and used to evaluate maximum evaporative and drift loss for the ultimate heat sink cooling tower. The maximum daily average and maximum consecutive 30-day average wet bulb temperatures were also chosen from the compiled daily average wet bulb temperatures to evaluate minimum heat transfer conditions to the atmosphere for the ultimate heat sink cooling tower.

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b. Refer to response to RAI 410.26.

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References to 451.12

1. Pease AFB, llourly Surface Observations TDF 14, January 1,1961 through Decemb6r 31, 1970, National Climatic Center, Asheville, North Carolina.

2. Boston NWS, Hourly Surface Observations, TDF 14, January 1,1945 through December 31, 1973, National Climatic Center, Asheville, North Carolina.

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.. I 451.13 In response to Question 451.02 of the review of the Environmental (2.3) Report, on-site meteorological data for the period June 1980 -

(FSAR) May 1981 were submitted in the form of joint f requency

, distributions of wind speed and wind direction by atmospheric stability. Provide hour-by-hour data for this additional period of record on magnetic tape in the same format used to submit data for the period April 1979 - March 1980 (see ER Question 451.01).

RESPONSE: A magnetic tape containing a file of hour-by-hour meteorological data from the On-Site Meteorological Measurements Program for the period June 1980 - May 1981 has been provided. (Raference 1)

Reference 1: PSNH letter, dated March 2, 1982

" Response to RAI 451-13" J. DeVincentis t'o F.J. Miraglia 9

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451.14 A comparison of three years of on-site meteorological data (11/71 -

(2.3) 10/72, 4/79 - 3/80 and 6/80 - 5/81 indicates significant (FSAR) variability in the f requency of atmospheric stability conditions, particularly for unstable (Pasquill types "A", "B" and "C") and slightly stable (Pasquill type "E") conditions. For example, for the period November 1971 - October 1972, unstable conditions were observed about 10% of the time, while slightly stable conditions were observed about 32% of the time. However, for the period April 1979 - March 1980, unstable conditions were observed about 21% of the time, while slightly stable conditions were observed only about 24% of the time. For the latest period of record (June 1980 - May 1981), unstable conditions were observed almost 27% of the time, with about 12% classified as extremely unstable (Pasquill type "A"), while slightly stable conditions were observed only about 17% of the time,

a. Provide a discussion of _the year-to year variability of unstable and slightly stable conditions at the Seabrook site, and discuss the reasonableness of the large fraction (in excess of 20%) of unstable conditions observed at Seabrook since April 1979, considering the atmospheric mechanisms for generating thermal instability, the classification scheme used, the location of the meteorological tower and the surface characteristics around the tower, and the location of the site. Also indicate why the increased frequency of unstable conditions appears to occur at the expense of the / -

frequency of slightly stable conditions while the frequencies 4 of other stability classes remain relatively constant from year-t o-year.

b. Provide information on the persistence of each stability class in a form similar to Table 2B-5 in Appendix B of the FSAR for the periods April 1979 - March 1980 and June 1980 -

I May 1981. ,

l RESPONSE: a. The causes of the year-to-year variability in atmospheric l

stability measurements at the Seabrook site are currently under review. A response will be provided by May, 17, 1982.

l

b. Stability persistence summaries for the periods April 1979 -

March 1980 and June 1980 - May 1981 are provided in Tables 451.14-1 and 451.14-2, respectively.

TAliLE 451.14-1 (Sheet 1 of 2) _ j STABILITY PERSISTENCE

SUMMARY

, APRIL 1979-MARCII 1980

a.43-150 Foot Delta-Temperature STABILITY PERSISTEiG

SUMMARY

- HUMBER OF OBSERVATIONS AND PERCENT PROBABILITY STABILITY PERSISTENCE (HOURS) -

STABILITY ! 2 3 4' 5 ' '6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAL

'A  !!!' 51 31 712 ,13 3 7 2 3 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 236 47 69 82 87: 92 /94 .97 97. 99 100 100. 0 0 0 ,. 0 m O. 0. 0 0 0 0-.0 -0 0- 0 B 297 100 47 2 8 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 476 62 83 93 98 100 100 0, 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0' C , 319 55 10 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 'O 0 0 0 0 388 82 96 99 100 0 0 0 0 ,0 0 0 .0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 333 180 136 70 .36 34 32 13 14 15, - S 16, 9 8 3 5 5 5 2,2 2 1 3 0 5(a) 937 36 55 69 77 81 84 ,83 89 91 92,93 795 96 96 97 97 98 98 99 99 99 99 99 99 100 E 327 133 73 46 32 20 17 13 19 9 9 0 8 3 2 0 2 1 0 0 0 0 0 0 0 709 45 64 74'81 85 88 91 93 95 96 96 ,98 99 99 100 100 100'100 0 0*0 0 0 0 0 F 210 76, 24 11 13 1 2 3 1 0 0 40,'d 0 0 0 0 0 ,0 0 0 0 0 0 0 341 62 84 91 94 98 98 99 100 100 0 0 .t,0 0 0 0 0 0 0 0 0 0.0 0 0 0 61 33 12 12 6 11 9 4/3 3 4 2 0 0 0 0 0 0 0 0 0 0 'O 'O 0 160 38 59 66 74 78 84 90 93 94 96 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL 1653 628 333 177 108 71 67 35, 40 29 22 18 17 11

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5 5 7 6 2 2 2 1 3 0 5 3247

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(a)Of these. 5 occurences of,. D stability which persisted,'over 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:

o one lasted 28'hourc "

oene: lasted 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> o one lasted 33 houhs '

o one.-lasted 40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> o one lasted 44 hours5.092593e-4 days <br />0.0122 hours <br />7.275132e-5 weeks <br />1.6742e-5 months <br />

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TABLl? 4$ 1.14-1 (Sheet 2 of 2)

b.43-209 Foot Delta-Temperature STA3!LITY PERS!STENCE

SUMMARY

- NUMBER OF OBSEWATIONS AND PERCENT FROBABILITY STABILITY PERSISTENCE (HrxRs)

STABILITY I 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAt.

A 59 22 2 '5 2 2 1 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 97

, .- - 61 84 86 91 93 95 96 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0-0 ,

B 141 42 15 4 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 203 69 90 ?8 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C 233 90 34 19 4 0 .0 0 0 0 0 0 0 0 0 0 0 0 .0 0 0 0 0 0 0 380 61 85 94 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

. D 265 165 123 75 44 38 25 17 17 8 13 14 5 6 7 5 3 2 5 2 3 1 0 1 12(a) 856 31 50 65 73 79 83 86 88 90 91 92 94 95 *5 96 97 97 97 98 03 93 ?8 98 99 100 E 276 157 68 58 50 35 15 18 19 18 9 3 5 9 5 1 1 1 0 1 2 1 0 0. 0 752 37 58 67 74 81 86 88 90 93 95 96 97 97 98 99 99 99 99 '99 100 100 100 0 0 0 .

F 185 83 38 18 to 6 4 ,0 1 0 0 0 0 0 0 0 0 0.0 0 0 0 0 0 0 350 53 73 89 94 97 99 100 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 44 19 15 9 7 11 10 3 4 0 7 3 0 0 0 0 0 0 0 0 0 0 0 'O v 132 33 48 59 66 71 80 87 89 92 92 93 100 0 0 0 0 0 0 0 0 0 0 0 0-0 4

TOTAL 1202 583 295183118 92 55 40 43 26 29 20 10 15 12 6 4 3 5 3 5 2 0 1 12 2770

- (*)0f these 12 occurences of D etability which persisted over 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:

o two lasted 25 hours o two lasted 32 hours3.703704e-4 days <br />0.00889 hours <br />5.291005e-5 weeks <br />1.2176e-5 months <br /> o two lasted 26 hours o one lasted 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> o one lasted 27 hours o two lacted 44 hours5.092593e-4 days <br />0.0122 hours <br />7.275132e-5 weeks <br />1.6742e-5 months <br /> o one lasted 28 hours o one lasted 46 hours5.324074e-4 days <br />0.0128 hours <br />7.60582e-5 weeks <br />1.7503e-5 months <br />

TAlit.E 451.14-2 (Sheet I of 2) _

STABILITY PERSISTENCE

SUMMARY

JUNE 1980-MAY 1981

c.43-150 Foot Delta-Temperature STABILliY FERS!STENCE SJNMARY - NJMBER OF OBSERVATIONS AND PEY.ENT PROBA8ILITY STABilliY FTRSISTENCE 04XRS)

TOTAL

. STABILITY I 2 3 4 5 6 7 8 9 to 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 97 49 36 23 -26 16 19 14 6 5 5' 2 0 0 0 0 0 0 0 0 0 0 0 0' 0 300 A

33 49 61 69 78 83 .89 94 96 98 99 100 0 0. . 0 . 0 0 0 0 0 0 0 0 0 0 474 B 311 105 32 16 5 1 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 66 88 95 98 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 337 C 251 56 19 6 3 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 74 91 97 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 'O O 0 0 0 0 0 324 154 79 51 46 27 21 17 15 14 17 9 10 14 7 6 6 2 1 8 2 0' 2 1 8(N 841 39 57 66 72 78 S1 83 85 87 89 91 92 93 95 96 96 97 97 98 98 99 99 99 99 100 E 313 120 63 .41 .32 24 10 3 4 4 5 0 1 0 0 1 0 0 0 0 0 0 0 0 0 621 50 70 80' 86 92 95 97 98 98 99 100 100 100 100 100 100 0 0 0 0 0 0 0 0 0 F 210 75 31 17 5 2 2 1 0 0 0 0 0 0 0 0 0 0 0. 0 0 0 0 0 0 343 61 83 92 97 99 99 100 100 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 69 27 14 14 10 12 6 3 8 2 2 0 1 0 0 0 0 0 0 0 0 0 0 0 ,0 .168 0

41 57 .65 74 80 87 90 92 97 98 99 99 100 0 0 0 0 0 0 0 0 0 00 0 3064 TOTAll577 586 274 168 127 83 62 39 33 25 29 11 12 14 7 7 6 2 1 8 2 0 2 1 8 (0)0f these 8 occurences of D stability which persisted over 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:

o one lasted 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> o one lasted 35 hours4.050926e-4 days <br />0.00972 hours <br />5.787037e-5 weeks <br />1.33175e-5 months <br /> o one lasted 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> o one lasted 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> o one lasted 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> o one lasted 41 hours4.74537e-4 days <br />0.0114 hours <br />6.779101e-5 weeks <br />1.56005e-5 months <br /> o one lasted 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> o one lasted 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />

.. m- - 4 e . -- p.

rAllt.E 4S t .14-2 (Sheet 2 of 2) _

b.43-209 Foot Delta-Temperature STABilliY FERSISTENCE

SUMMARY

- NLME.R OF 08SERVAil0NS AND PERCENT PROBABILITY STABILITY ftRS!STEtCE IH0lRS)

STABILITY l 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAL A 70 33 14 9 11 5 5 7 2 0 .0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 156 45 66 75 31 88 91 94 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8 195 67 26 11 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 302

- 65 87 95 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C 231 78 23 4 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 389 12 92 98 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 259 140 101 57 35 22 21 23 21 12 12 10 12 6 8 10 4 6 4 4 1 1 3 1 15(* 7b8 33 51 63 71 75 78 81 84 86 88 89 90 92 93 94 95 96 96 97 97 97 98 98 98 100 ,

E 302 142 79 55 39 24 18 81210 5 1 8 :i 0 1 0 0 0 0 1 0 0 0 0 710 43 63 74 81, 87 90 93 94 96 97 98 98 99 100 100 100 100 100 100 100 100 0 0 0 0 F 205 82 42 23 !! 3 5 1 0 1 1 0 0 0 0 0 0 0 00 0 0 0 0 0 374 55 77 83 94 97 98 99 99 99 100 100 0 0' 0 0 0 0 0 0 0 0 0 0 0 0 0 49 21 25 10 9' !! 5 2 10 5 1 1 1 0 0 0 0 0 0 0 0 0 00 0 150 33 47 63 70 76 83 87 88 95 98 99 99 100 0 0 0 0 0 0 0 0 0 0 0 0 TOTAll341 563 310 169 110 66 54 41 45 28 19 12 21 11 8 !! 4 6 4 4 2 1 3 1 15 2869 (a)0f these 15 occurences of D stability which persisted over 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:

l l o three lasted 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> o one lasted 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> l o three lasted 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> o one lasted 42 hours4.861111e-4 days <br />0.0117 hours <br />6.944444e-5 weeks <br />1.5981e-5 months <br /> o one lasted 28 hours3.240741e-4 days <br />0.00778 hours <br />4.62963e-5 weeks <br />1.0654e-5 months <br /> o one lasted 45 hours o one lasted 29 hours3.356481e-4 days <br />0.00806 hours <br />4.794974e-5 weeks <br />1.10345e-5 months <br /> o one lasted 46 hours o one lasted 31 hours3.587963e-4 days <br />0.00861 hours <br />5.125661e-5 weeks <br />1.17955e-5 months <br /> o one lasted 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> o one lasted 33 hours3.819444e-4 days <br />0.00917 hours <br />5.456349e-5 weeks <br />1.25565e-5 months <br /> l

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451.15 Provide the percent recovery for each of the following parameters (2.3) for the periods April 1979 - March 1980 and June 1980 - May 1981:

(FSAR) wind speed at the 43-foot and 209-foot levels; wind direction at the 43-foot and 209-foot levels; vertical temperature difference 1

between the 43-foot and 150-foot levels; vertical temperature i difference between the 43-foot and 209-foot levels; and ambient 4

dry bulb temperature at the 43-foot level.

RESPONSE: Wind speed, wind direction, temperature, and delta temperature data recovery rates for the periods April 1979 - March 1980 and June 1980 - May 1981 are provided in Table 451.15-1.

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TABLE 451.15-1 METEOROLOGICAL DATA RECOVERY RATES Recovery Rate

. Parameter Apr. 79 - Mar. 80 Jun. 80 - May 81 l

43-Foot Wind Speed 98.8% 99.9%

209-Foot Wind Speed 98.6% 99.9%

43-Foot Wind Direction 98.5% 99.4%

209-Foot Wind Direction 98.8% 99.9%

43-Foot Temperature 98.8% 99.9%

43 - ISO-Foot Delta Temperature 98.1% 96.9%

43 - 209-Foot Delta Temperature 98.6% 99.7%

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Composite (43' WS, 43' WD, 43.- 150' DT) 97.7% 96.4%

Composite (209' WS, 209' WD, 43 - 209' DT) 98 3% 99.6%

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451.16 a. Provide a detailed description of the calibration procedures (2.3) (sensor, electronics and complete system) used at Seabrook.

(FSAR)

b. Provide a description of the preventative maintenance program used during the data collection program operational since April 1979, identify periods of extended instrument outage since April 1979 and identify the causes of the outages and corrective actions taken.

c. Provide a detailed description of the quality control checks used to identify invalid hourly data.

RESPONSE: a. Routine calibration activities are performed every three months through a contract with TRC Environmental Consultants, Inc. The calibration activities are performed under a quality assurance program which meets the requirements of Appendix B to 10CFR Part 50.

During a routine calibration visit, technicians perform a detailed inspection of the meteorological monitoring equipment at the site. All components in the system are checked for proper installation, signs of wear, and other items which could affect equipment operation.

During each calibration visit, the wind direction transmitters are oriented to approximately N, E, S and W using the crossarm as a reference. Every six months, wind transmitters are rotated with spares. Af ter removal from the tower, the transmitters are calibrated , cleaned and if necessary overhauled. The wind speed transmitters are wind tunnel tested to check their accuracy and starting speed.

The wind direction transmitters are checked for shaf t and hub assembly end play and linearity.

Both the temperature and delta-temperature systems a're checked with ice baths. The dew point sensor readings are l

compared to readings from a calibrated psychrometer. The rain gauge is checked by tipping the rain bucket 50 times and by pouring a known volume of water into the collector. The I solar radiation sensor is removed and sent to the manufacturer for calibration on a yearly basis.

l The system electronics are checked by putting each translator card into a zero and span mode. The strip chart recorders are calibrated by inputting a series of voltages from zero to full scale in increments of 20 percent of full scale.

l The translator card output voltages and analog chart values I are recorded for each of the above activities and are checked i

to see if the values fall within specified tolerances. All l

measurements found out of tolerance are corrected through l

either adjustments or replacements of components. Data l adjustment factors are developed and applied to the data base for any instrumentation found out of tolerance.

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b. The object of the preventative maintenance program is to obtain the highest data recovery possible. The site is visited twice a week by a specially trained site technician who checks the equipment for normal operation. A visual check of the tower, guy wires, and instruments is performed.

All parameters are reviewed to see that the data look realistic, and all recorders are checked to see that they have the correct time and are inking or printing properly.

Temperature aspirator motor currents are checked

- assure their proper operation. Translator card zero and span checks are performed and both the solar radiation sensor and s the precipitation collector are cleaned with each visit. A site log is maintained at the site which documents all activities which occur at the site. A site checklist is also used to assure all important functions are performed during the twice weekly site visits.

In addition to the twice weekly site visits, the digital data base is automatically telemetered to Yankee Atomic every six hours where it is reviewed every working day by a meteorologist. If equipment malfunctions are suspected by either the site technicians or the Yankee Atomic meteorologist, and if the site technician is unable to solve the problem himself, the meteorological vendor (TRC) is called in order to have the problem resolved as soon as possible.

A review of extended instrument outages (extended outages being defined as continuous periods of missing data 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> long or longer), the causes of the outages, and corrective actions taken is provided in Table 451.16-1.

c. Af ter receipt of thedigital data base from the site via remote telemetry, a quality control flagged listing ,of the data base is produced. The criteria used to flag suspect data are defined in terms of extreme values, seasonal or diurnal disparities, extraordinary frequency of conditions,

unusual successions of events, and unusual relationships j between simultaneous values at multiple levels. These criteria are intended only to flag suspect data and are not intended to make the final decision on data to be discarded.

The entire data base is further examined by a meteorologist who considers such f actors as internal compatibility of the record, continuity, relationships among variables, the concurrent synoptic situation, and topographic influences j before judging any data to be unacceptable. Correction i

factors resulting from instrumentation calibrations are applied to the data base whenever appropriate. All data that

are suspect and cannot be verified are removed from the deta i base and are not used in the data summaries and analyses.

The strip charts are used as a backup source of data and for quality control analysis. They are received from the site once a week and are checked for obvious sensor and recorder malfunctions. Strip chart data are randomly digitized and compared with corresponding digital data to ensure

consistency between the two recording systems. Whenever possible, gaps in the digital data base are replaced with data digitized from the strip charts.

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TABLE 451.16-1 EXTENDED ON-SITE METEOROLOGICAL INSTRUMENT OUTAGES APRIL 1, 1979 - JUNE 30, 1981 No. of Parameter Time Period Hours Lost Cause Corrective Action Precipitation 4/5/79 - 4/13/79 192 Faulty switch in rain gauge. Switch was replaced.

All 5/4/79 - 5/7/79 69 Power loss in instrument shed. Power was restored.

Dew Point 5/7/79 - 5/6/81 Intermittent Instrument malfunction The General Eastern Outages dew point system was replaced with a Climatronics Model DP-10 lithium chloride dew point system.

43' - 150' DT 4/3/80 - 5/27/80 1328 Faulty temperature shield Aspirator motors were 43' - 209' DT aspirator motors. replaced. (Monitoring equipment have since been installed to verify operation of all aspirated motors.)

Solar Radiation 12/23/80 - 2/17/81 1346 . Sensor removed for factory Sensor was restored.

calibration.

Precipitation 2/19/81 - 3/2/81 256 Broken signal cable in Cable was replaced. ,

underground conduit.

451.17 Provide a complete description of the meteorological measurements (2.3) program (including control room display) to be available during (FSAR) plant operation, considering the criteria for emergency planning described in NUREG-0654 and Regulatory Guide 1.97. Also indicate how conditions such as fumigation, plume trapping, and seabreeze circulation will be considered in emergency planning.

RESPONSE: Major components of the planned operational meteorological measurements program are described in the answer to ER RAI 451.08. Other specific criteria for' operational meteorological measurement programs as outlined in NUREG-0654 and Regulatory

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Guide 1.97 are still under review. A complete description of the operational meteorological measurements program will be provided when all aspects of the program are finalized.

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451-18 The atmospheric transport and dif fusion model presented in (2.3) Section 2.3.5 apparently considers fumigation and trapping of l (FSAR) elevated plumes during seabreeze and onshore gradient flow conditions using empirical criteria for the formation and geometry of the thermal internal boundary layer.

a. Provide estimates of seasonal (spring an? summer) frequencies of seabreeze conditions at the Seabrook 4te.

b. Based on the criteria presented on pages 2.3-27 and 2.3-28 of the FSAR concerning formation of the TIBL, provide seasonal (spring and summer) frequencies of TIBL formation.

c. Provide a comparison of the topographic features examined in Ref erences 36, 37 and 39 of Section 2.3 of the FSAR for the shape of the TIBL with topographic features at the Seabrook site.

d. Provide the annual frequency of plume intercept with the TIBL for elevated releases from the primary vent stack.

e. For releases from the primary vent stack, provid'e a comparison of annual average relative concentration (X/Q) and relative depcsition (D/Q) calculated considering fumigation and trapping with annual average X/Q and D/Q values calculated without considering fumigation and trapping.

f. Spatial and temporal variations in airflow trajectories, particularly airflow reversals during the onset of the seabreeze and curved trajectories during the decay of the seabreeze, have not been explicitly incorporated into the annual average transport and diffusion model for the Seabrook site. Recent comparisons of the results of variable-trajectory models with the results of the straight-1,ine model at coastal nuclear plants (e.g., Perry and St. Lucie) have indicated that the straight-line model may underpradict X/Q values by factors of two to four. Provide further justification for not modifying the results of the straight-line model to consider spatial and temporal variations in airflow such as would be experienced during the onset and decay of the seabreeze.

RESPONSE: The frequency of seabreeze and thermal internal boundary layer occurrence and their effect on the annual average transport and dif fusion model are currently under review. A response will be provided by July 19, 1982.

451.19 The description of the current on-site meteorological measurements (2.3) program states that the low-level wind speed and direction

( FSAR) sensors and temperature dif ference sensor are located at a height of 43 feet above the surface. The standard height for low-level as asors is 10m (see Regulatory Guide 1.23, 1972, and Proposed Revision 1, September 1980). Provide justification for this deviation from the recommended height of low-level instruments.

RESPONSE: The meteorological tower is located at an elevation of approximately 8 feet MSL, and as such, the low-level wind and temperature sensors are approximately 51 feet MSL. Since plant grade is 20 feet MSL, the low-level sensors are located at an elevation of approximately 10m above plant grade rather than 10m AGL. The difference in values measured at 33 feet (10m) AGL versus 43 feet ACL on the meteorological tower should not be significant .

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