t

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sEAnaOM sTAM

IPUBLIC SERVICE L6:: 's Office:Companyof NewHampshw e 1671 Worcester Road

Framingham, Massachusetts 01701

(617). 872- 8100

tdO' ,-,

'R . 'lMarch 12,1982

6}# M A '

#8 'O

SBN-233 '_) 4 :3Q

T.F. B 7.1.2 9 Ae/,

I g hf,CUnited States Nuclear Regulatory CommissionWashington, D. C. 20555

At tentio n : Mr. Frank J. Miraglia , ChiefLicensing Branch #3Division of Licensing

Re f ere nc es : (a ) Construction Permits CPPR-135 and CPPR-136, DocketNos. 50-443 and 50-444

(b) USNRC Let ter, dated February 12, 1982, " Request forAdditional 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 inRe f e re nc e ( b) .

Very truly yours,

YANKEE ATOMIC ELECTRIC COMPANY$

OJAJohn DeVincentis

'

Project Manager

JDV : ALL: dad

ROOEnclosure Y g

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8203160530 920312PDR ADOCK O'000443A 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.

|

|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

and Unit #2 building complexes.|

!

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- -_ _ - _ . . . _ - -___ - -

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..

Marshall's method consists of determining the number of lightning

2flashes 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,

2thunderstorm days per km near the Seabrook site (Reference 2,

p. 30) and that the Seabrook site experiences 18.9 thunderstormdays per year (Pease AFB data, SB FSAR Table 2.3-la), there are

2approximately 2.55 flashes to earth per year per km around theSeabrook 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 toconservatively 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, processbuilding, fuel storage building, and containment

structure.

H = 56m

Defined by the height of the primary vent stack.

! 2A = 0.135 km

Unit #2: L = 200m, W = 90m

|

- - . __ .

. .

..

Defined roughly by a rectangle outlined by theturbine 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

2flashes to earth per km , the estimated frequencies of alightning 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 buildingcomplexes. 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 2.3-2presents the more conservative estimates of lightning strikes forthe Seabrook site.

References to 451.10

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

|

| 2. Marshall, J. L. , Lightning Protection, John Wiley & Sons, New York,1973.I!

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RAI 431,11 !

|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 combustionair inl:ake and exhaust system discussed in section 9.5.8).

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

; duration).t

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

,

| 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," Probability Estb' as of Temperature Extremas for the Contiguous t!nited'~

states"), and other extreme conditions for atmospheric, moisture andprecipi,tation. -

,,

RESPONSES -

, . ,

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

.

a. Meteorc .

; systes[are summarissMb$1'dwfth'(eInsratoriair'.iin"ei Gi"r'o|Esihtdlid'ons>for' ';ponentsiffezclusive . o fittisidiese17 "10 ' .sad coo

~

!exhaustthe diose1' generator' air' intake'and enhaust oystea ai,Caddriised'iEd N jT~ '' -

'

RAI'430.130. '

| .,,

Extreet Outdoor. Temperatures'

,

&zimum 880F ',__.

! Ml.nimum 0*f~

Relative Outdoor Busidity

Mximum 100%' *

1

Mi.nimum 101 , u -,

, .

.

vetemperatureandhumidityestrNsLwereutilisedth[tEs.,, des.ign ')|The abo

a temperature and humidity 'environi(buildingsr TlieTEVA4 systems .RVAC systems forza11ssafety-related .'of the,

ent'alwithinitbe'ibnil'd sTae . m_'

maintal #

'specified in FSAR Figure-3.11(3)-1;(serjidisTEnvi'riissIsnti,dinit $$57door gooditions[specified5'above Q d @ % i % [m~ .W. v(a}-.

g$I,| the out . _1'

.7 ; F'- v-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'' ~

-velocit les as follows:4

1.

| * ~ ~~ .'"~~~~''7gy,r "_ ':' p~9,= ~~g" '." *Q T *"T ' , [ :""" ' *-- _..

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J AM.08 ' 80 22:03 GMT SLnuxuuA dinsawniw,

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SB 1 & 2FSAR

Severe Environmental Load*..

wind speed of 110 mph at 30 feet above ground for a 100 yearAr eturn period.

Extress Envirotusental Ioads

total maximum tornado wind velocity (translational plusAotational of 360 mph.)r

Category I structures and certain non-Seismic Category ISeismi :ares were designed for the following atmospheric pressure changestruct<

.

accomp anying the design basis tornado-

m- w., , .

otal pressure change due to passage of tornados 3 psi ,,~ * *- ~ - - . . , _ __

T ;

tt..of pressure change: 2 psi per secondE e

ses for specification of temperature extremes are actual measured~

'

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

of the distributions were used. ~

1- i . . ..

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

(

re:humidifiesfatfor near 100.jpered' a.ctoccuriduring,fogWdew;fpressThe ba'relati

ia%precip~i'.:ation' which are frequently observed?in'this7 climate.;adIdicies*1'ess than 10 percent"are not! observed und'erJthe - gtion s

g 'Rafa^tt,

rclimatic conditions affecting this site. . _

V

ses for the design' wind velocities and atmospherie pres's.ures'for -|>

P' Tha bac Category..I structures and'cartain non-Category I structuresseismi

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

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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

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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 hours 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) wereanalyzed 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.

l

b. Refer to response to RAI 410.26.

|

.

. .

-

.

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 throughDecember 31, 1973, National Climatic Center, Asheville, North Carolina.

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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 atmosphericstability. Provide hour-by-hour data for this additional period

of record on magnetic tape in the same format used to submit datafor the period April 1979 - March 1980 (see ER Question 451.01).

RESPONSE: A magnetic tape containing a file of hour-by-hour meteorologicaldata 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.

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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") andslightly 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 conditionswere observed about 32% of the time. However, for the periodApril 1979 - March 1980, unstable conditions were observed about21% of the time, while slightly stable conditions were observedonly about 24% of the time. For the latest period of record (June1980 - May 1981), unstable conditions were observed almost 27% ofthe time, with about 12% classified as extremely unstable(Pasquill type "A"), while slightly stable conditions wereobserved only about 17% of the time,

Provide a discussion of _the year-to year variability ofa.unstable and slightly stable conditions at the Seabrook site,and discuss the reasonableness of the large fraction (inexcess of 20%) of unstable conditions observed at Seabrooksince April 1979, considering the atmospheric mechanisms for

.

generating thermal instability, the classification schemeused, the location of the meteorological tower and thesurface characteristics around the tower, and the location ofthe site. Also indicate why the increased frequency ofunstable 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 fromyear-t o-year.

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

I May 1981. ,

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

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

|

b. Stability persistence summaries for the periods April 1979 -March 1980 and June 1980 - May 1981 are provided inTables 451.14-1 and 451.14-2, respectively.

_

,

!

,

TAliLE 451.14-1* '

(Sheet 1 of 2) _ j

STABILITY PERSISTENCE SUMMARYAPRIL 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 23647 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 47662 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 38882 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) 93736 55 69 77 81 84 ,83 89 91 92,93 95 96 96 97 97 98 98 99 99 99 99 99 99 1007

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 70945 64 74'81 85 88 91 93 95 96 96 ,98 99 99 100 100 100'100 0 0*0 0 0 0 0

40,'d 0F 210 76, 24 11 13 1 2 3 1 0 0 0 0 0 0 ,0 0 0 0 0 0 0 34162 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 5 5 7 6 2 2 2 1 3 0 5 3247,/

'',, " /, .,s

. /*,r '

' /(a)Of these. 5 occurences of,. D stability which persisted,'over 24 hours:

..., -,,

o one lasted 28'hourc'

o''ene: lasted 32 hours "

o one lasted 33 houhs 'one.-lasted 40 hourso

o one lasted 44 hours,

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(Sheet 2 of 2)_

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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

.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

4

(*)0f these 12 occurences of D etability which persisted over 24 hours:-

o two lasted 25 hours o two lasted 32 hourso two lasted 26 hours o one lasted 36 hourso one lasted 27 hours o two lacted 44 hourso one lasted 28 hours o one lasted 46 hours

'

.- - . . . . ,

- .. -. . -

TAlit.E 451.14-2, ,

(Sheet I of 2)_

STABILITY PERSISTENCE SUMMARYJUNE 1980-MAY 1981

.

'.

c. 43-150 Foot Delta-Temperature

STABILliY FERS!STENCE SJNMARY - NJMBER OF OBSERVATIONS AND PEY.ENT PROBA8ILITY

STABilliY FTRSISTENCE 04XRS)

. 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 TOTAL

A 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

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

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 0 474

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. . . .

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 0 337

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 84139 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

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

41 57 .65 74 80 87 90 92 97 98 99 99 100 0 0 0 0 0 0 0 0 0 00 0

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 3064

(0)0f these 8 occurences of D stability which persisted over 24 hours:

o one lasted 25 hours o one lasted 35 hourso one lasted 27 hours o one lasted 36 hourso one lasted 28 hours o one lasted 41 hourso one lasted 30 hours o one lasted 50 hours

.

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

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

_

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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 hours:|

| o three lasted 25 hours o one lasted 36 hours

| o three lasted 27 hours o one lasted 42 hourso one lasted 28 hours o one lasted 45 hourso one lasted 29 hours o one lasted 46 hourso one lasted 31 hours o one lasted 50 hourso one lasted 33 hours

|

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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 atthe 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 ambient4

dry bulb temperature at the 43-foot level.

RESPONSE: Wind speed, wind direction, temperature, and delta temperaturedata recovery rates for the periods April 1979 - March 1980 andJune 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|

.

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%

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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Provide a detailed description of the calibration procedures451.16 a.

(2.3) (sensor, electronics and complete system) used at Seabrook.(FSAR)

b. Provide a description of the preventative maintenance programused during the data collection program operational sinceApril 1979, identify periods of extended instrument outage-

since April 1979 and identify the causes of the outages andcorrective actions taken.

c. Provide a detailed description of the quality control checksused 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 aquality assurance program which meets the requirements ofAppendix B to 10CFR Part 50.

During a routine calibration visit, technicians perform adetailed inspection of the meteorological monitoringequipment at the site. All components in the system are

,

checked for proper installation, signs of wear, and otheritems which could affect equipment operation.

During each calibration visit, the wind directiontransmitters are oriented to approximately N, E, S and Wusing the crossarm as a reference. Every six months, windtransmitters are rotated with spares. Af ter removal from thetower, the transmitters are calibrated , cleaned and if

,necessary overhauled. The wind speed transmitters are windtunnel tested to check their accuracy and starting speed.

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

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

| compared to readings from a calibrated psychrometer. Therain gauge is checked by tipping the rain bucket 50 times andby pouring a known volume of water into the collector. The

I solar radiation sensor is removed and sent to themanufacturer for calibration on a yearly basis.

| The system electronics are checked by putting each translatorcard into a zero and span mode. The strip chart recordersare calibrated by inputting a series of voltages from zero tofull scale in increments of 20 percent of full scale.

|The translator card output voltages and analog chart values

I are recorded for each of the above activities and are checkedi to see if the values fall within specified tolerances. All| measurements found out of tolerance are corrected through

either adjustments or replacements of components. Data|

l adjustment factors are developed and applied to the data basefor any instrumentation found out of tolerance.

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b. The object of the preventative maintenance program is toobtain the highest data recovery possible. The site isvisited twice a week by a specially trained site technicianwho checks the equipment for normal operation. A visualcheck 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. Asite log is maintained at the site which documents allactivities which occur at the site. A site checklist is alsoused to assure all important functions are performed duringthe twice weekly site visits.

In addition to the twice weekly site visits, the digital database is automatically telemetered to Yankee Atomic every sixhours where it is reviewed every working day by ameteorologist. If equipment malfunctions are suspected byeither the site technicians or the Yankee Atomicmeteorologist, and if the site technician is unable to solvethe problem himself, the meteorological vendor (TRC) iscalled in order to have the problem resolved as soon aspossible.

A review of extended instrument outages (extended outagesbeing defined as continuous periods of missing data 48 hourslong or longer), the causes of the outages, and corrective

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actions taken is provided in Table 451.16-1.

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

: unusual successions of events, and unusual relationships

j between simultaneous values at multiple levels. Thesecriteria are intended only to flag suspect data and are notintended to make the final decision on data to be discarded.The entire data base is further examined by a meteorologistwho considers such f actors as internal compatibility of therecord, continuity, relationships among variables, theconcurrent synoptic situation, and topographic influences

j before judging any data to be unacceptable. Correctionfactors resulting from instrumentation calibrations arei

applied to the data base whenever appropriate. All data that; are suspect and cannot be verified are removed from the detai base and are not used in the data summaries and analyses.

The strip charts are used as a backup source of data and forquality control analysis. They are received from the siteonce a week and are checked for obvious sensor and recorder

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malfunctions. Strip chart data are randomly digitized andcompared with corresponding digital data to ensure

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consistency between the two recording systems. Wheneverpossible, gaps in the digital data base are replaced withdata digitized from the strip charts.

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TABLE 451.16-1

EXTENDED ON-SITE METEOROLOGICAL INSTRUMENT OUTAGESAPRIL 1, 1979 - JUNE 30, 1981

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No. ofParameter 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 EasternOutages dew point system was

replaced with aClimatronics Model DP-10lithium chloride dewpoint system.

43' - 150' DT 4/3/80 - 5/27/80 1328 Faulty temperature shield Aspirator motors were

43' - 209' DT aspirator motors. replaced. (Monitoringequipment have since beeninstalled to verifyoperation of allaspirated 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.

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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 planningdescribed in NUREG-0654 and Regulatory Guide 1.97. Also indicate

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how conditions such as fumigation, plume trapping, and seabreezecirculation will be considered in emergency planning.

RESPONSE: Major components of the planned operational meteorologicalmeasurements 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~

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 |

(FSAR) elevated plumes during seabreeze and onshore gradient flowconditions using empirical criteria for the formation and geometryof the thermal internal boundary layer.

Provide estimates of seasonal (spring an? summer) frequenciesa.

of seabreeze conditions at the Seabrook 4te.

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

Provide a comparison of the topographic features examined inc.

Ref erences 36, 37 and 39 of Section 2.3 of the FSAR for theshape of the TIBL with topographic features at the Seabrooksite.

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

For releases from the primary vent stack, provid'e ae.

comparison of annual average relative concentration (X/Q) andrelative depcsition (D/Q) calculated considering fumigationand trapping with annual average X/Q and D/Q valuescalculated without considering fumigation and trapping.

f. Spatial and temporal variations in airflow trajectories,particularly airflow reversals during the onset of theseabreeze and curved trajectories during the decay of theseabreeze, have not been explicitly incorporated into theannual average transport and diffusion model for the Seabrooksite. Recent comparisons of the results of variable-trajectory models with the results of the straight-1,ine modelat coastal nuclear plants (e.g., Perry and St. Lucie) haveindicated that the straight-line model may underpradict X/Qvalues by factors of two to four. Provide furtherjustification for not modifying the results of thestraight-line model to consider spatial and temporalvariations in airflow such as would be experienced during theonset and decay of the seabreeze.

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

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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 heightof 43 feet above the surface. The standard height for low-level

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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 andtemperature 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) AGLversus 43 feet ACL on the meteorological tower should not be

significant .

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