ML20073S849

Rev 1 to Calculation 1961-2.2-004, MNGP Toxic Chemical Analysis Probability Analysis of Trucking Accidents

ML20073S849
Person / Time
Site:	Monticello
Issue date:	04/11/1993
From:	TENERA, L.P. (FORMERLY TENERA CORP.)
To:
Shared Package
ML20073S848	List: ML20073S846 ML20073S849 ML20073S852
References
1961-2.2-004, 1961-2.2-004-R01, 1961-2.2-4, 1961-2.2-4-R1, NUDOCS 9407060294
Download: ML20073S849 (16)

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o Ec" 2 ' ot5ic" COVER SHEET w ECP.3.3 CALCUL.ATION MNGP Toxic Chemical Analysis O ECP.2.3 ENC. EVALVATION SUBJECT o oTHER Probability Analysis of Trucking Accidents MNGP Toxic Chemical Study Updat 1961-2.2 004 CONT. l.C' NO' PROJECT Northern States Power Company NO or ssis. 916 /.h CUENT PURPOSE / DESCRIPTION The purpose of this calculation is to conservatively determine the probability that a trucking accident on highways near the Monticello Nuclear Generating Plant involving hazardous materials will incapacitate the control room operators and result in a radioactive release in excess of 10 CFR 100 guidelines. The calculation will use probabilistic techniques to determine the probability of such an occurrence and will compare this probability to the acceptance criteria stated in Section 2.23 of the NRC Standard Review Plan.

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Subject:

MNGP Tnvic chemien1 Annlytic Prepared By Checked By ' - Date I Prnhnhility Annlycic nf TmeHng Accidente Project: MNnP Tnric chemieni study 11,ndnte Rev. 1 Sheet 1 of _1L Sheets l A Control I.D. No.1061 ? ? nM 1.0 Pu. rpose The purpose of this calculation is to conservatively deterrrine the probability that a trucking accident involving hazardous materials will incapacitate the Monticello Nuclear Generat!ng Plant (MNGP) control room operator:; and result in a radioactive release in excess of 10 CFR 100 guidelines.

/

NRC Standard Review Plan (SRP) Section 2.2.3 (Ref.1) states in regard to offsite hazards that "the expected rate of occurrence of potential exposures in excess of the 10 4

CFR Part 100 guidelines of approximately 10 per year is acceptable if, when combined

,with reasonable qualitative arguments, the realistic probability can be shown to be lower." This calculation will demonstrate that this criterion is met for trucking accidents involving hazardous materials in the vicinity of the MNGP.

2.0 References

1. U.S. NRC Standard Review Plan, Section 2.2.3, " Evaluation of Potential Accidents," Revision 2, July 1981.

2. " Truck Trends in Minnesota - An Examination of Truck Traffic and Accidents from 1984 thru 1990," July 1991, Truck and Economic Studies Section, Minnesota Department of Transportation.

3. MNGP Drawing NF-108565-2, Revision B.

4. Publication No. FHWA RD-89-013,"Present Practices of Highway Transportation of Hazardous Materials," May 1990, U.S. Department of Transportation, Federal Highway Administration.

5. TENERA Correspondence File 1961-2.4-013, confirmation letter from C. Dahlin (MN Dept. of Transportation) regarding truck traffic information on Interstate 94 and Highway 10.

6. NSP Nuclear Analysis Department calculation for MNGP, " Level 1 Sensitivity Studies," Calculation No. II.SMR.90.026,

7. TENERA Calculation 1934 2.2-005, " Chlorine and Ammonia Probability Analysis," Revision 1, August 12,1991.

TENERA Date ib .

Subject:

MNGP Tnvic Chemtenl' Annlytit Prepared By Prnhnhility Annlytic nf Trucking Accirients Checked By - '

Date b Project: MNnP Tnvic chemient sterly findnf e Rev. 1 Sheet ? of L4_ Sheets l A Control I.D. No.1%1.9 9.nM

8. TENERA Calculation 1934-2.2 006, " Revised Chlorine and Anunonia Spill Estimates," Revision 1, December 11,1991.

9. Monticello Calculation CA 92-012, Attachment 5, "Monticello Toxic Cilemical Study Update - Accidental Chlorine Release Analysis," Preliminary issue.

10. TENERA Calculation 19612.2-001, " Verification of TOXPUFF and TOXEVAP Lotus 1-2-3 Spreadsheets," Revision 0, March 15,1993.

11. TENERA Calculation 1961-2.2 002," Analysis of Toxic Chemical Spills Using the Lotus 1-2-3 Spreadsheet TOXPUFF," Revision 0, March 15,1993.

12. TENERA Calculation 1961-2.2-003," Analysis of Toxic Chemical Spills Using the '

Lotus 1-2-3 Spreadsheet TOXEVAP," Revision 0, March 15,1993.

13. U.S. NRC Regulatory Guide 1.78," Assumptions for Evaluating the Hab'tability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release," June 1974.

14. U.S. AEC Safety Evaluation for Monticello Nuclear Generating Plant Unit No.

1, Full Term Operating License, February 5,1973 (DSS Sequence #HEJ00501).

15. Monticello Procedures Manual A4, Volume 2, " Chemical Spill / Hazardous Materials Procedures."

16. Telecon between G. Kellund (TENERA) and W. Martinson (MN DOT),

" Highway Traffic Data on Highways 25 and 75," April 2,1993.

3.0 Methodolocy The probability that a release from a trucking accident involving hazardous materials would incapacitate the control room operators and result in a radioactive release in excess of the 10 CFR 100 guiduines is determined by the solution of the following equation:

Pm = (Txa) X (Dusx) X (Nraucxs) X (Fuxz) X (Rxec) X (Rod X (Poi)

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TENERA M Date ydMW

Subject:

_ MNGP Tnvic Chemien1 Annlytic Prepared By Checked By -

Date 'l!hlW l Prnhnhility Annlycie nf TmcHng Accidente Project: MNGP Tnvic Chemieni Rtudy IIndnte __

f Rev. 1 Sheet 9 of 14 Sheets l A Control I.D. No.1o619 ? 004 l

s ,

I where P> m = Probability of a release in excess of 10 CFR 100 guidelines per year due l

i to a trucking accident involving hazardous materials.

4

Tu = Trucking accident rate per mile.

i Dmg = Length of highway segment (in miles) where a release in this segment could potentially result in transport to the control room and operator incapacitation. This value is also weighted to account for wind direction probability at any point in the segment.

Number of commercial trucks traveling on highways of concern per year.

Nrauca = '

= Fraction of commercial trucks that carry hazardous material.

F>az R3cc = Fraction of trucking accidents involving hazardous materials that result in

! a release or spill.

Roi = Fraction of hazardous materials releases that are severe enough to

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< potentially result in control room operator incapacitation.

2 Poi

= Probability of exceeding _10 CFR -100 guidelines _ given operator 4

incapacitation (per shift).

i Each of the above terms will be discussed in detail in Section 7.0 of this calculation.

i 4.0 Acceptance Criteria As noted in Section 1.0 above, a probability of exceeding 10 CFR 100 guidelines due to f 4 i operator incapacitation resulting from a trucking accident of 10 per year is acceptable

if, when combined with reasonable qualitative arguments, the realistic probability can be shown to be lower. If this criterion is met, no actions or measures are required to

- protect the operators from this event.

5.0 Assumptions i Assumptions used in the development of this calculation are as follows: j A,

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TENERA .

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Subject:

MNGP Tnvic Chemien1 Annlytic Prepared By Date 4M3 Date I Prnhnhilitv Annlytic nf TrucHng Accidente Checked By l

j Project: MNGP Tnvic Chemical Study lindnte __

l Rev. _1 Sheet 4 of 14 Sheets l A i Control I.D. No.1o61.? ?.0n4 i

1. Accident rates for combination trucks are representative of all truck types that may carry hazardous materials. The majority of hazardous material transported by truck in quantities sufficient to pose a risk to the MNGP is transported by combination trucks (i.e. large shipments of toxic liquids and gases constitute the primary threat; these materials are typically transported by tanker truck). Also, the accident rate for other truck types is not expected to be significantly different

from that for combination trucks.

2. All severe releases within a five mile radius of the MNGP are conservatively j assumed to incapacitate the control room operators if the wind is blowing in the direction of the MNGP.

. 3. Only Interstate 94 and Highway 10 carry sufficient truck traffic in the vicinity of the MNGP to warrant consideration in the calculation. Justification for this i assumption is provided in the discussion of the Dmx term in Section 7.0.

4. Reference 4 states that "between 5 percent and 15 percent of all trucks on the

' road at any given time carry hazardous materials." Table 35 of Reference 4 notes

/ that 5.2% of all truck accidents involve hazardous shipments. Consequently, this g l

calculation will assume that 5.2% of all truck traffic carries hazardous materials.

?

5. Any release that does not meet the U.S. Department of Transportation definition ,

! of " severe" is not capable of incapacitating the control room operators. This assumption is supported by the fact that in order to incapacitate the operators, i a release would have to travel at least one-half mile (the closest approach of a

! highway to the MNGP) and would necessarily incapacitate anyone in that one-

! half mile long path. It is doubtful that any release capable of incapacitating anyone up to one-half mile away would not meet the definition of " severe."

l

6. The operators did not initiate a plant transient (i.e. a reactor scram) prior to

incapacitation. This assumption is consistent with operating procedures and

operator training. The procedures for handling toxic gas releases (Ref.15] fo not direct the operators to scram the reactor.

7. The probability of core damage resulting from operator incapacitation is conservatively assumed to equal the probability of radioactive releases exceeding  ;

10 CFR 100 guidelines.

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8. No outside intervention or assistance occurs for the remainder of the shift i

following operator incapacitation.

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Subject:

' MNGP Tnric Chemieni Annlycic Prepared By Date , M{N'3

Prnhnhilitv Annlycic nf TrucHng Accidente Checked By .d Dats N/dU Project: MNGP Tnvic Chemient Study IIndnfe Control I.D. No.1M1M %nM Rev. 1 Sheet - 4 of _1L Sheets l A!

i I 6.0 Desien Inputs l

! Design inputs used in this calculation (as noted in Section 3.0) were obtained from the references given in Section 2.0. The specific source and applicability of each design input used will be noted in the appropriate part of Section 7.0 of this calculation.

L 7.0 Calculation As stated above, the probability that a release from a trucking accident involving hazardous materials would incapacitate the control room operators and result in a l

radioactive release in excess of the 10 CFR 100 guidelines is determined by the solution of the following equation:

! Puw = (T a) 3 X (Dmx) X (Nraucu) X (Farz) X (R cc) 3 X (Roi) X (Poi)

This calculation will be performed separately for each highway of concern near the MNGP. The results for each highway will then be summed to produce the overall j probability for all trucking accidents.

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Each term in the equation, and the source of the value used is discussed below.

1 Taa: The trucking accident rate per mile was obtained from Reference 2. This

[

i reference was used because it provided a' breakdown of accident rates by i road type (interstate or principal arterial) and by location (urban or rural).

Interstate 94 is in a rurallocation in the vicinity of the MNGP and passes l

l within approximately one-half milp of the MNGP. Reference 2 provides an overall accident rate of rural interstates, and 1.27per )0.80 per 10' miles fortrucks semitrailer on ruraltrucks i

10' miles for twin trailer i

interstates. Since semitrailer trucks account for approximately 98% of the I total rural interstate miles traveled by combination trucks in Minnesota 4

i (per Ref. 2), a scaled overall trucking accident rate of 0.81X10 fer mile g provides a realistic estimate for ruralinterstate highways. This value will j

be used for the overall trucking accident rate on Interstate 94. It should l

be noted that in the vicinity of the MNGP, Interstate 94 is quite straight l

and flat and could be expected to have an accident rate less than the value used here.

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TENERA

Subject:

KfNGP Tnvic Chemien1 Annlytic Prepared By N Date O Prnhnhility Annlysit nf TmcHng Accidents Checked By

• Date 'l!lI[@

Project: KfNGP Tnvic Chemien1 Study Iindnte Control I.D. No. 1061.99.nN Rev. 1 Sheet 6 of 14 Sheets l A The other highway of concern for this calculation is Highway 10. Highway 10 passes within approximately two miles of the hiNGP and is treated as a principal arterial highway for the purposes of this calculation. Reference 2 provides an overall a cident rate of 1.27 per 10' r'niles and 1.20 per 10'.

miles for semitrailer trucks and twin trailer trucks, respectively, on rural principal arterial highwayy This calculation will conservatively use the l A 4

higher value of 1.27X10 per mile for the overall trucking accident rate for Highway 10.

The accident rate values given above for combination trucks can be assumed to be representative of all truck types that may carry hazardous materials for the following reasons: The majority of hazardous material transported by truck in quantities sufficient to pose a risk to the hiNGP A is transported by combination trucks (i.e. large shipments of toxic liquids and gases constitute the primary threat; these materials are typically transported by tanker truck). Also, the accident rate for other truck types is not expected to be significantly different from that for combination trucks.

Dmx: The length of highway segment where a release could potentially transport to the control room and incapacitate the operators was determined from Reference 3 by assuming all portions of a highway within five miles of the MNGP could produce such a release. The boundary was set at five miles to be consistent with the guidance given in Regulatory Guide 1.78 [Ref.'

13]. This is clearly a very conservative assumption since References 10,f 11, and 12 demonstrated that the release of highly incapacitating materials (e.g. chlorine) from a rail accident two miles from the MNGP and in much larger quantities than those transported by truck did not produce operator incapacitation.

In order to account for the potential effects of wind direction on the probability of release transport to the control room, the Dmx term is weighted by multiplying the fraction of the time that the wind is in a particular sector by the highway miles in that sector. This is performed for each sector that the highway passes through within five miles of the MNGP. The results for each sector are then summed to produce an equivalent length of highway where the wind direction is always toward the MNGP. The sectors of concern were obtained from Reference 3 and are shown graphically in Figures 1 and 2 for Interstate 94 and Highway 10, respectively. Wind direction data from 1984 to 1991 was obtained from s

TENERA M

Subject:

MNGP Tneic Chamic91 Annlysis Prepared By Date 4'd'M Prnhnbility Annlytit nf TrucMno Accidente Checked By M Date M Project: _3fNGP Tnvic Chemient Study Undate Control I.D. No. 1061 9 ' 004 Rev. 1 Sheet 7 of 14 Sheets l A

/

Reference 9 and is tabulated in Table 1. Table 1 also shows the

" equivalent miles" of highway length.

It should be noted that only Interstate 94 and Highway 10 were included in this calculation since all other roads within five miles of the MNGP are much smaller than these highways and have considerably less truck traffic.

The only other roads in this area that could potentially carry significant amounts of truck traffic are Highways 25 and 75. According to traffic data #

supplied by the Minnesota Department of Transportation [Ref.16),

Highway 25 carries approximately 450 heavy commercial vehicles per day in the Monticello area. This traffic volume is much less than the combined traffic volume carried by Highways 94 and 10; further, since the point of closest approach of Highay 25 to the MNGP is approximately 3.5 miles, the Daisg term for this highway is small. Also, since the point of closest approach is over three miles from the plant, the potential for operator incapacitation from a spill is quite small, Consequently, since truck traffic on Highway 10 contributes only approximately 15% of the a total risk, truck traffic on Highway 25 will have an insignificant contribution to the total risk. For reasons similar to those given above, truck traffic on Highway 75 will have an insignificant contribution to the total risk. Although no data on commercial vehicle traffic is available for this roadway, total vehicle traffic on this road is substantially less than that "

on Highway 25. Further, as noted in Reference 16, very few heavy commercial vehicles would be expected on Highway 75 due to its size and location.

It should also be noted that since other roads tend to carry local traffic, very little hazardous material is transported on them. Further, any hazardous material transported in this area by truck is almost certain to enter the area via Interstate 94 or Highway 10 and would then be accounted for in this calculation.

Nrauens: The number of commercial trucks travelling on Interstate 94 and Highway 10 per year was obtained from the Minnesota Department of Transportation [Ref. 5]. Interstate 94 carries an average of 3,325 heasy commercial vehicles per day (both directions) north and south of the Highway 25 interchange at Monticello. Highway 10 carries an average of .l A 700 heavy commercial vehicles per day (both directions) in the vicinity of Monticello.

4 TENERA

Subject:

MNGP Tnvic chemien1 Annlysis Prepared By [M Date '/MS3 Checked By Date Y[lI[W Prnhnhility Annlycie nf Trncking Accidente Project: MNGP Tnvic rhemient (;tudy Undnte Rev.- 1 Sheet fL_ of 14 Sheets l 6 Control I.D. No. 1061 ? 9.004 9-According to Reference 16, heavy commercial vehicles are defined as vehicles of 2-1/2 ton size and larger. This category also includes buses. &

Consequently, essentially all trucks larger than pickups are accounted for in this calculation.

2 Reference 4 states that "between 5 percent and 15 percent of all trucks jo l Faz:

the road at any given time carry hazardous materials." Table 35 of Reference 4 notes that 5.2% of all truck accidents involve hazardous 6 l

shipments. Consequently, this calculation will assume that 5.2% ' of all i truck traffic carries hazardous materials.

The fraction of trucking accidents involving hazardous materials that result

Rs in a release were obtained from Table 35 of Reference 4 which documents that for the period 1981 to 1985, a total of 15.2 percent of truck accidents invoMng hazardous materials resulted in a release.

The fraction of hazardous materials releases that are severe enough to Rm:

potentially result in control room operator incapacitation was determined l

as follows: Reference 4, page 95, states that for the period 1981 to 1985, l A

1. 13,547 hazardous materials releases were reported to have ycurred on U.S. highways. Of this total,633 were considered to be " severe" which is defm' ed by the U.S. Department of Transportation (Ref. 4, page 96) as l A releases that involve either (1) a fatality or injury caused by the release; (2) property damage of $50,000 or more caused by the release; or (3) a fire or explosion. For the purposes of this calculation, it is assumed that any release that does not meet the definition of " severe" stated above is /

not caps.ble ofincapacitating the control room operators. This assumption is supported by the fact that in order to incapacitate the operators, a j

release would have to travel at least one half mile (the closest approach of a highway to the MNGP) and would necessarily incapacitate anyone in th9t one-half mile long path. It is doubtful that any release capable of j in apacitating anyone up to one-half mile away would not meet the definition of " severe." A Consequently, the Rm term is calculated as follows:

/

l Rm = (633)/(13,547) = 0.047

Pm: The probability of experiencing core damage when operator incapaci'.ation is assamed was determiped previously [Ref. 6L Jts value was deter nined j

to be 0.158 per year. This probability acco'mts for 111 potential core I

TENERA d3

Subject:

MNGP Tnvic Chemien! An91ysic Prepared By NI Date Prnhnhilitv Annlycic nf Triding Accidente Checked By I Date NhN Project: MNGP Tnvic Chemieni (;tudy Undnte l Rev. 1 Sheet 0 of 14 Sheets l A Control I.D. No. 1961.? % 004 i ,

damage initiating events (e.g. LOCA, Main Steam Line Break, Control l A

Rod Drop). Other accidents that have the potential for offsite releases ,

that do not involve core damage are an offgas storage tank rupture and a g fuel handling accident. The rupture of an offgas storage tank was evaluated previously [Ref.14],,and determined to fall well within 10 CFR 100 guidelines. A fuel handling accident concurrent with or resulting from i

operator incapacitation due to a toxic release is considered to be an extremely low probability event that does not require further consideration. Its extremely low probability is due to the small amount of time taken by fuel handling activities in a year, the low probability of operator incapacitation per year, and the low probability of significant

• offsite exposures given a fuel handling accident without operator intervention.

It should also be noted that the calculation performed in Reference 6 i

assumed that the operators did not initiate a plant transient (i.e. a reactor scram) prior to incapacitation. This assumption is consistent with i

! operating procedures and operator training. The procedures for handling toxic gas releases (Ref.15]'do not direct the operators to scram the reactor. Consequently, the use of the 0.158 per year probability value obtained in Reference 6 is appropriate for this calculation.

l For the purposes of this calculation, this probability value of 0.1583 r' is conservatively assumed to equal the probability of exceeding 10 CFR 100 i guidelines. To be meaningful for this calculation, this value must be converted to a per shift basis since for the consideration of this term the i

release is assumed to have occurred, been transported to the control room intake, and incapacitated the operators. At this point, the probability of

exceeding 10 CFR 100 guidelines during the shift that the operators are incapacitated must be determined. This calculation assumes a 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> operating shift and conservatively assumes that no outside intervention or l assistance occurs for the remainder of the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> shift following operator  !

i incapacitation. Since operator incapacitation has an equal probability of l l

4 occurring anytime during the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> shift, then the average amount of vulnerable time remaining in the shift following operator incapacitvion is 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

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Subject:

MNGP Tnvic rhemien1 Amlytic Prepared By M f- Date #643 Prnhnhilitv Annlytic nf TrucHng Accidente Checked By - -

Date N@

Project: MNGP Tnvic Chemimi Study Updnte Control I.D. No. 1516.1 ? ? 004 _ , . Rev. 1 Sheet to of 14 Sheets l A In this case, the Poit erm is:

Poi = (0.158/yr) X (12 hrs / shift) X (6 hrs /12 hrs / shift)/(8760 hrs /yr) l A cLehr') 14tta.

= 1.08X10 per shift d u,y gg y wwg Se~ \w 'tt%n doet M ek twld 64-Consequently, the probability per year of exceeding 10 CFR 100 3 limits d+ue t accident is:

Interstate 94 probability:

v s P>im = (0.81X(04acc/mi) X (0.78 mi) X (3,325 trucks / day) X d

A s /

(365 day /yr) X (0.052 haz/ truck) X (0.152 release /haz) X 4

(0.047 OI/ release) X (1.08X10 10CFR100/OI)

= 3.08X104 per year # A Highway 10 probability:

v v /

P>im = (1.27X104 acc/mi) X (0.54 mi) X (700 trucks / day) X A

s v (365 day /yr) X (0.052 haz/ truck) X (0.152 release /haz) X s-(0.047'bl/ release) X (1.')8X10" 10CFR100/OI)

/

= -7.03X104 per year )

/ s Total Probability = 3.08X104per year + 7.03X10* per year. A

/

= 3.78X104 per year l

TENERA f bject: MNGP Tnric chemten) Annlytts Prepared By MI f Date Md'3 Prnhnhility Annlyck nf TnicHng Accidente Checked By 0I Date Y[Ill91 Project: MNGP Torte Chemteni Situiy 11ndue Control I.D. No.1u1.9 9.nM Rev. 1 Sheet 11 of 1L Sheets l A 8.0 Conclusion The probability of a radioactive release from the MNGP in excess of 10 CFR 100 guidelines due to a trucking accident invoMng hazardous materials A than 3.78 is less 4

per year. This is well below the acceptance criterian of approximately 10 per year stated in Reference 1. Further, the actual probability is lower than the calculated value due to the numerous conservatisms used throughout the calculation. A further conservatism is the assumption that all " severe" releases will result in operator incapacitation. References 10,11, and 12 demonstrated that operator incapacitation will not occur for a wide variety of hazardous materials released from rail accidents in quantities much larger than those transported by truck. Consequently, no actions are required to protect the control room operators at the MNGP from hazardous materials transported by tmek.

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MNGP Tovie chemien1 Annlytit l'repared Ily [I Date f Prnhnhility Annlytic nf Tnicking Accidente Checked Ily FI- Date 'th'/'Il Project: MNGP Tnvic rhemtent Mtudy linante Control I.D. No. Igrit.? 9.nna Rev. 1.

Sheet 12. of .14 Sheets l 6 Table 1 Wind Direction Frequencies and Equivalent Illghway Miles Wind W!nd Frequency Illghway Miles Equivalent Miles Hichway . Sector in Sector (9M in Sector in Sector 1 94 SE 6.4 3.8 0.24 -

SSE 7.5 1.4 0.10 '

S 9.1 0.4 0W SSW 7.6 0.3 0.02 v SW 4.2 0.2 0.01 -

WSW 3.9 0.3 0.01 '

W 5.6 0.7 0.04 -

WNW 7.0 4.5 0.32 /

Total: 0.78 miles V Hwy 10 E 4.0 2.9 0.12 -

ENE 3.7 1.1 0.04 v NE 4.4 0.9 0.04 -

NNE 4.1 1.0 0.04 -

N 5.0 1.7 0.09 -

NNW 9.8 2.1 0.21 -

Total: 0.54 miles l A v

Note: Equivalent Miles are calculated as follows:

Equivalent Miles = (Wind Frequency in Sector) X (Highway Miles in Sector) + 100 I

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Subject:

MNGP Tnvic rhemlent Annlytic Prepared By Date f D Prnhnhility Annlytic nf TmeMng Ace 41 ente Checked By &* Date N'/##

Priject: __MNGP Tnric chemten1 Rtudy Undnfe Control I.D. No.1061 ' mi Rev. 1 Sheet _.11. of _1L Sheets l 6 Figure 1 imd Sectors of Concern for Interstate 94

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MNGP Tnvic rhemien1 Annlytic '

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