ML18046A786

Forwards Safety Evaluation for SEP Topic II.2.A Re Severe Weather Phenomena,Incorporating Util 810311 Responses. Tornado Characteristics Addressed in Reg Guide 1.76 Provide Adequate Design Basis During Tornado for Facility

ML18046A786
Person / Time
Site:	Palisades
Issue date:	06/30/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
RTR-REGGD-01.076, RTR-REGGD-1.076, TASK-02-02.A, TASK-2-2.A, TASK-RR LSO5-81-06-135, LSO5-81-6-135, NUDOCS 8107130445
Download: ML18046A786 (8)

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Docket No. 50-25,5. _

LS05-8l-06-l35.

Mr. David P. Hoffman Nuclear Licensing Administrator Consumers Power Company 1945 W. Parnall Road Jackson, Mich19;an 49201

Dear Mr. Hoffman:

June 30, 1981

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SUBJECT:

PALISADES - SEP TOPIC 11.2.A, SEVERE WEATHER PHENOMENA E~closed is the staff's final safety evaluation {SE) for Topic II.2~A, "Severe Weather Phenomena" for the Palisades site. This evaluation takes into account the comments provided in your letter dated

• March l l, 1981. A 11 of the comments in your letter have b~en.

incorporated' with the exception of straight wind and tornado loadings.

With respect to straight winds, the 85 mph represents the predicted extreme value wind of about 80 mph plus one standard deviation and is the 100 year return period wind. This analysis was provided in.~BS Building Science-Series 118, "Extreme* Wfod Speeds at 129 Stations in. -

the Contiguous United States, 11 from the G*rand Rapids :National Weather Servke Station. It is the sta"ff's opinion that the 'Grand Rapids statio.n is more representative of *the Palisades site than the Mu~H~gan-station. In addition, a value of 85 mph is suppqrted by the analysis of -extr.e_me wind speed presented in ANSI A58.2.

There.fore, the staff will con.ttnue to use the 85 mph value as the design wind speed.

Your response also indicated a concern regarding the*staff's design basis tornado.

The staff's proposed design basis tornado, based originally <?n Regulatory Guide 1.76 has subsequently been detennined by McDonald in his report 11Tornad9 and Straight Wind Hazard Probability for Palisades Nuclear Power.Reactor Site, Michigan" as approximating the expected l0-7 tornado at the Palisades site. Since the hazard probaoility' analysis was developed using storm records from the geographical region surrounding the site, the staff feels the design basis tornado transm.itted 1.n the *g*riginal evaluation is appropriate for the Palisades site.

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.OFFICE *................... **********************................................................................... ********************* ********************

SURNAME~.................................................................. *************!******* ********************* ***************.******** *********************

DATE~. ******************** ********************* **********************. ********************* *********************.......

NRC FORM 318 1101801 NRCM 0240 OFFICIAL RECORD COPY

,-, USGPO: 1980-329-824

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Th1s evaluation will b.e a bas.ic input to the integrated safety a_ssessment..

. for your facility *. This assessment may be revised in the future if your facility design is changed or if the NRC criteria relating to the subject is modified before the integrated assessment is complete.

Enclosure:

As stated cc w/enclosure:

See next **page

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Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing OFFICE ** g.~.=J:~*t. :..... P.UL.. '...... Q~.; g~?,{.~v.:*.. P.~ -i:?ffe!W-1"-... P.~/,(l'J.G.... iiiJ.4P/..~fl..........................

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NRCFORM318(10/801NRCM0240 OFFICIAL RECORD COPY

. "1USGP0:1980-329*824

Mr. David P. Hoffman cc M.

I~**Miller, Esquire Isham, Lincoln & Beale Suite 4200 One First National Plaza Chica~o, illinois. 60670 Mr. Paul A. Pe~~y:, Secretary Consumers Power Co1~any 212 West Michigan Avenue Jackson, :Mic~igan 49201 Judd L. Bacon, Esq~ire Consumers Pov1er Company 212 West Michigan Avenue Jackson, Michigan 49201 Myron M. Cherry, Esquire Suite 4501 One I Bf:1 Plaza Chic~go, Illinois 60611 Ms. Mary P. Sinclair Great _Lakes Energy Alliance 5711 Summerset Drive Mi.dland, Michigan 48640 Kalamazoo Public Library 315 South Rose Street Kalamazoo, Michigan. 49006

. Townsh.ip Super.visor Covert Township Route 1, Box 10 i.

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u. S. Environmental P~otection

• Agency*

Federal Acthdties Branch

. R.egi on. V Offjc~'.:

ATTN:* EIS C.OOR'D:INATOR 230 South.(}ear.b&rn Street

~2~"i ca go~. I 11 i no{s 60604

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• "Cha.rles *Be:chhoefer, Esq., Chairman*

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Atomic Safety.: and Licensing Board Panel

'U.* ::.*:s~ Nuclear Regulatory Commission W,ashington, o. c.

20555

• Dr *. *Beorge *C. *Anderson Depart.rnent of Oceanography-

. Uni vers-ity of Washington Seattle', Washington 98195 Dr. M. Stanley Livingston 1005 Calle Largo Santa Fe, -~i::w Mexico :87501 R~sident Inspector c/o*U. s-. NRC..

P. *a:. Box 87.

• South H~ven, Michigan 49090 Van Buren County, Michigan 49043 Office of the Governor (2)

Room l - Capitol Building Lansing, Michigan 48913 William J. Scanlon, Esquire 2034 Pauline Boulevard Ann Arbor, Michigan 48103 Palisades Plant ATTN:

Mr. Robert Montross Plant Manager Covert, Michigan 49043

. ENCLOSURE 1

• Systematic Evaluation Program Palisades Nuclear Generating Station Topic 11~2.A'-

S~vere*w~~ther Phenomen~*

Extreme meteorological conditions and severe weath~r phenomena in the Palisades site region were examined to determine if safety-related structures, systems, and components are desigried to f~nction under all severe weather conditions.

Discussed below are the severe weather phenomen~ which could adversely aff~ct ~he Palisades site and which should be examined relative to the current de~ign.

Normal dailY temperatures range from a minimum of 14 degrees Fahrenheit in January to a maximum of 80 degrees Fahrenheit _in July. Measured extr~me temperat~res for the site region are 109 de~rees Fahrenheit and

-21 degrees Fahrenheit.

The extreme maximum and minimum temperatures appropriate ~t the Palisades site for general plant design (i:e., HVAC systems) a.re 90 degrees Fahrenheit.(equ_alled or excee~ed 1% of ~he time) and

~l degrees Fahrenheit (eq~alled or exceeded 99% of the time).

Thunderstorms occur an average of 42 days per year in the site region.

Based on the annual num.ber of* thunderstorm days, the calculated annual flash density of ground lightning strikes is six flashes per square kilometer.

A structure with approximate dimensions of the Palisades reactor building can be expected to be subjected, on the average, to one strike every three years*.

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The design w-fod-speed (defined-as the "fastest,,.mile" w'.ind s_peed at a height of _30 feet above ground level with a: ret_urn pe;t.Jod of 100 years)

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On the avera*ge,

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hail storm~_occur at two days a~nually, ~n~ free~Jng t~in otcu~~

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approxi_malelY 12 days per year. *The ma~imum radial thickness of ice

£ expecte'd in the site region is ab'b1:J't 1.75.inches, with_ the exc;:eption of the transmission line and towers in th(~1inmediate vicinity of the pl anL *Due to the 1oca1 effe~~~s of th!= coo l__i.'rig towers, local fee loading on the lines and towers may accumulat~'Up to a maximum radial ice thickness of 5 inches.

Mean annual snowfall in the site region is* approximately 55 inches,*

resulting in a normal vJinter precipitation snow loa'd on a flat surface of about 25 pounds per iquare foot.

T~ regional max~mum monthly snowfall occurred in March 1965 and totaled ~6.0 inches.

The maximum snowfall:from a single storm totaled 25 inches in December 1937.

The maximum measured snow depth* on the ground,.fur the s,ite region. is 35 inches.

Based on the 100-year recurrence a~cumula~ed ground snowpack, and the 48 hbur probable maximum winte~ pr~cipitation_for the site region, the snow load 6n a flat surface is about 90 pound~ per square foot.

Tornadoes have been reported 130 times during the period 1950-1977 within an approximate 60-mile radius from the Palisades site, exdluding the water area over Lake Michigan.

On the average, five tornadoes can be expected to occur in the vicinity of the Palisades site every year.

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• Based on the path length and width data from iornadoes occurring in the site*~eQion, ~he recurrenc~ interval fo~ ~*to~n~do at the sit~ is ~alcu

. lated _to be about _500 years.

• The assumptions* used in Regulatory Guide 1.76 provide an adequate design basis tornado for the site region.

These characteristics include a maximum

_ wi ndspeed of 360. mi 1 es per hour (a maxi mu in rot at i anal wi ndspeed of 290 miles -

per" hour plus a maximum translatiOnal windspeed of 70 miles per hour), a maximum pressure drop of three pounds per square inch, and rate of pressure drop of two pounds per square inch per ~econd.

Based o~ a~tual tornado occurrences in the *site region area and using the procedures discussed in WASH-1300, a "site-specific" design basis to~nado (with a* *probability of occurrence of 10-- 7 per.year) can be calculated *. The use of site-specific data for Palisades provides windspeeds and pressure dr6ps which are higher than those recorrrnended in Regulatory Gui de 1. 76.

A tornado wi.th a 360 mi.le per hour maximum windspeeds (as retornmended in the guide) has a probability of occurrence oi 10 - 5 per year, based on tornado occurrence~*

within 60 miles of Palisades, as oppposed to the desired 10 ~

7 per year pr*obabi l ity.

However, exami nat i.on of the tornado data, varying the area examined aro~nd the plant fo~ tornado occurrences, and an~lysis*of the uncertainties and bias inv~lve~i in th~ ~eporting of ~ornado occurrences' indicates that a 360 mile per hour maximum windspeed probably has a lower

_probability than 10 - 5 per year.

Therefore, we feel Regulatory Guide 1.76 tornado characteristics will provide an adequate design basis tornado for Palisades.

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References

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U.S *.Department of Commerce, N,OAA, "Climates of t"fie States,*-',Vol. *1, 197.4.

i U.S. Department of Corrmerce~ "Climatic Atlas**of the Uni;ted States,"

June 1968. *

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U.S~ Departmerit of 1973. *.. *.... >- -

NO.AA; "C 1 i mates pf th~lfA;{~d States,"

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U. S. D ep a:;t:.n;e ~t of C or.ime rce, No~.86-16, Climatic Summary Cl irnatography of the United 'states of t~?,l.Jnited States, Michi~an," 196~. *

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u.s*~ Del)artrnent of Cont;1erce.

~~.\\~;.. 1., *"~'.:iCai (limatu1ogica1 'oata, II iliuskegon, Grand. Rapids, and Lansing, Micti*iga.K~ 1976...

H~ c. s. Thom, "New Distributi.ons of Extreme Winds in the United States,"

Journal of the Structural Divis~fon, ASCE, Vol. 94, No. ST}, July 1968 *

. "A;nerican National Standard Bu.ilding Cod~ Requ.(rements for Minimum.

Design.loads in Buildings and Other Structures,'.'.ANSI, A58.l-1972.

• "Seasonal Variation of the. Pr~bable Maxirrumir~cipitation East of the 105th Meridian for Areas from 10 to 1,000 Square Mi'les and.Durations of 6, 12, 24, and 48 Hours," Hydrorneteorological Report No. 33,_

Washington, D. C., Ap ri 1 19 56.

James A. Ruffner.*and Frank E. Ba*ier, "The Weather Almanac,*" Gale Research Corrpany, 1974~

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David M* Ludlum, "Weather Record Book," 14eatherwise, *Inc., 1973.

J. L. Marsha11, "Lightning Protection," John Wiley. and Sons, New*York, 1973.

"ASHRAE Handbook of Fundamentals," American Society of Heat i. ng, Refrigeration and Air Conditioning Engineers, Inc., Nevi York 1976.

Paul Tattleman a-nd Irving I. Gringorten, "Estimated Glaze Ice and Wind Loads at the Earth's Surface for the Contiguous Uniteq**states,"

Air Force Carr1bridge Research Laboratories; Octo_ber 197.~~

U.S. Housing and Horne Finance Agency, ;~snow Load Studies,". Housing Research Paper No. 19, May 1952,-

U.S. Naval Weather Service, 011World-Wide Airfield Summaries," Vol. v*lII, United States of America, Part 4, 1969.

Simiu, E., et al, "Extreme Wind. Speeds at* 129 Stations in the Contiguous United State~' NBS Building Science Series 118, u. s.

Department of Commerce, Washington, D. c., March 1979.

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Memo fro~ Harold R.'Denton (A~sistant Otrectoi fat Site Safety, Division*

of Technical Review, NRR) to R. R. Maccary (Assistant Director for

• Engineering, Division o~.Technical Revi~w, NRR} d~ied March 24, 1975,

Subject:

S.ite Analysis Branch Position - Winter Precipitation Loads. * *.

Memo from Jerry Harbour (Chief, Site Safety Rese~rch Branch, DivisiOn of Reactor Safety Research, RES) tol. G. Hulman (Chief, Hydrology..:.

Meteorology Branch, Division of Site Safety and Environmental Analysis, NRR.) dated r\\ugust 14, 1970,

Subject:

Tornado Frequency Data for SEY Review.

Regulatory Guide 1.76, ~'Design Basis Tornado for Nuclear Power Plants,"

U.S. Nuclear Regulatory Commission,- Washington, O.C.

WASH-1300, "Technical Basis f6r Interim Regional Tornado Criteria,"

U.S. Ato:nic Energy Com:;iission, May 1974.

H. c. s.* Thom~ ;,Tornado Probabilities~ H Monthl.Y Weather Review, October-December 1963~ pp. 730-736~.

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