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Revision 33 to the Updated Final Safety Analysis Report, Section 2, Site and Environs
	ML16054A416
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Site:	Monticello
Issue date:	01/26/2016
From:	; Northern States Power Co, Xcel Energy
To:	; Office of Nuclear Reactor Regulation
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SECTION 2

Revision 22 USAR 2.1MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 1 of 1SECTION 2SITE AND ENVIRONS I/djm2.1Introduction The Monticello site was thoroughly investigated as a site for a nuclear power plant and found to be suitable as evidenced by issuance of a construction permit (Docket No. 50-263) on June 19, 1967.Section 2 contains information on the site and environs of the Monticello Nuclear Generating Station.FOR ADMINISTRATIVE USE ONLYResp Supv:CNSTP Assoc Ref:

SR:2yrs N Freq: USAR-MANARMS:USAR-02.01Doc Type:Admin Initials:Date:

9703 SECTION 22.22.2.1

2.2.2

2.2.3 2.2.4

2.2.5

2.2.6 Revision

25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 1 of 33SECTION 2SITE AND ENVIRONS I/cah2.3Meteorology2.3.1GeneralTravelers Research Corporation analyzed the meteorology of the plant site.

Initial design criteria related to meteorology were based on data taken at St.

Cloud and Minneapolis. Since the original Facility Description and Safety

Analysis Report was written, a meteorological program was established to

provide actual on-site meteorological data. The data obtained from this program are summarized in USAR Tables 2.3-5 through 2.3-20 These data confirm the adequacy of the initial design criteria used in the plant design.

The general climatic regime of the site is that of a marked continental type characterized by wide variations in temperature, scanty winter precipitation, normally ample summer rainfall, and a general tendency to extremes in all climatic features. Of special interest are the extremes in annual snowfall, which may be as little as six inches or as much as 88 inches; a temperature range of

145°F for the period of record; occasional severe thunderstorms with heavy rainfall and high winds; and the possibility of an occasional tornado or ice storm.

These and other pertinent meteorological data are presented in the following sections.2.3.2TemperatureAverage and extreme monthly air temperatures for the Monticello site are not available, but 54 years of data for St. Cloud and Minneapolis - St. Paul have been adjusted to give representative average values for the site area. The site

is approximately 13 miles closer to St. Cloud than to Minneapolis. A summary of monthly air temperatures from January to December is given in Table 2.3-1.2.3.3Precipitation Precipitation in the Monticello area is typical for the marked continental climate, with scanty winter precipitation and normally ample summer rainfall. The months

of May through September have the greatest amounts of precipitation; average

fall of rain during this period is 17-18 inches, or more than 70% of the annual rainfall. Thunderstorms are the principal source of rain during May throughSeptember and the Monticello area normally experiences 36 of these annually.

The heaviest rainfall also occurs during a particularly severe thunderstorm. A summary of precipitation statistics is shown in Table 2.3-2 (based on St. Cloud and Minneapolis - St. Paul averages). Average monthly snowfall statistics aregiven in Table 2.3-3.

Intense rainfall is produced by an occasional severe thunderstorm. The return period of extreme short interval rainfall is a useful guide. The nearest location for which return period data are available and which should be reasonably representative for the Monticello area is Minneapolis. This data is shown in Figure 2.3-1.01081199 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 2 of 33 I/cahSnow load data available from a Housing and Home Finance Agency (HHFA)study conducted in 1952 (Reference 18) are given in Table 2.3-4.

Data relating to freezing rain and resultant formation of glaze ice on highways and utility lines are available from the following studies:American Telephone and Telegraph Company, 1917-18 to 1924-25(Reference 19)

Edison Electric Institute, 1926-27 to 1937-38 (Reference 20)

Association of American Railroads, 1928-29 to 1936-37 (Reference 21)Quartermaster Research and Engineering Command, U.S. Army, 1959(Reference 22)The U.S. Weather Bureau also maintains annual summaries. The following is a fairly accurate description of the glaze-ice climatology of middle Minnesota.Time of occurrence - October through April Average frequency without regard to ice thickness, 1-2 storms per year Duration of ice on utility lines - 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (mean) to 83 hours9.606481e-4 days 0.0231 hours 1.372354e-4 weeks 3.15815e-5 months (maximum of record)

Return periods for freezing rain storms producing ice of various thickness are:

0.25 inch - Once every 2 years 0.50 inch - Once every 2 years

0.75 inch - Once every 3 years2.3.4Winds and Wind Loading The preoperational meteorological data program is described in Sections 2.3.4 and 2.3.5 of the FSAR. The Monticello plant is currently provided with a 100-meter meteorological tower. Wind speed, direction, and temperaturedifference instrumentation is located at approximately ten meters and at theelevation of the plant effluent point (43 meters and 100 meters). In addition, temperature and rainfall instruments are provided. Meteorological data is used

to compute dispersion (X/Q) and deposition (D/Q) factors for use in the dose

assessment of airborne releases. Wind speed, direction, and atmosphere stability class are averaged over the release period and serve as inputs to adispersion model. Stability class is determined using temperature difference

measurements between the ten meter elevation and the elevation of the release.

Wind frequency distributions for the 10 and 100 meter tower elevations for theperiod January 1, 1980 through December 31, 1980 are presented in Tables2.3-5 through 2.3-20. The distributions are for Stability A through G, as definedin Table 1 of the proposed revision 1 to Regulatory Guide 1.23 issued September 1980 (Reference 39). Annual average dispersion factor (X/Q) and deposition per unit area (D/Q) were computed for this period and are presented in Tables 2.3-22 through 2.3-27. NRC computer code XOQDOQ was used for thesecalculations (Reference 14). This historical data may be useful in estimatingoff-site doses due to routine releases of airborne radioactive effluents from the

reactor building vent and plant stack.

Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 3 of 33 I/cah Wind frequency distributions for the 10, 43 and 100 meter tower elevations for the period of January 1, 1998 through December 31, 2002 were prepared foruse in calculating atmospheric dispersion coefficients for design basisradiological consequences analysis using Alternative Source Term Methodology (reference USAR Section 14.7). These distributions appy only to the accident

analyses.2.3.4.1Tornadoes and Severe Thunderstorms Severe storms such as tornadoes are not numerous, but they do occur occasionally. The latitude of the Monticello site places it at the northern edge of the region of maximum tornado frequency in the United States, but only a fewtornadoes have occurred in this vicinity. Eight tornadoes have been reported in Wright County during the period 1916-1967, two of which subsequently moved across the Mississippi River into Sherburne County.

A 1-degree square 1 , lying between 45 and 46 degrees north, and between 93 and 94 degrees west, encompasses the Monticello site. There have been approximately eight tornado occurrences reported in this 1-degree square in

the 14-year test period, 1953-1966. The ratio of eight tornadoes in 14 years gives a mean annual tornado frequency of 0.6. This frequency is confirmed bythe Mean Annual Tornado Frequency figures published by the U.S. Department of Commerce, Weather Bureau (Reference 31).

Using the methods described by H. C. S. Thom (Reference 2), with a mean annual tornado frequency of 0.6, the probability of a tornado striking a given

point in the outlined 1-degree square, which encompasses the Monticello site, can be calculated to be 5x10

-4 per year, or one tornado every 2000 years. Theeffects of the tornado phenomenon including possible effects of missiles andwater loss effects in the fuel pool are discussed in Reference 3 of this section.Subsequently, it was determined the drywell head could become a missilehazard for the spent fuel pool, however, since the probability is less than 10

-7 , it is not a credible missile.

The average number of thunderstorms for Minneapolis and St. Cloud is 36 withmore than half of these occurring in June, July, and August. Therefore, it is expected that the Monticello site may experience an average of 36 thunder-storms annually. The fastest wind recorded for 54 years of record for each month at Minneapolis is given in Table 2.3-21.2.3.4.2Conclusions The meteorology of the site area is basically that of a marked continental area with relatively favorable atmospheric dilution conditions prevailing. Diffusion climatology comparisons with other locations indicate that the site is typical of the North Central United States. Frequency of inversion is expected to be 30-40% of the year.1.In this area, a 1-degree square is approximately 3,354 square miles.01081199 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 4 of 33 I/cahThe site is located in an area occasionally traversed by storms and tornadoes.

Maximum reported wind speed associated with passage of storm is 92 mph.2.3.5Plant Design Based on MeteorologyThe station is designed with an off-gas stack to be used for continuous dispersal

of gases to the atmosphere. Based on meteorological data at the site, plant operational characteristics, and stack design, the off-site doses arising from

routine plant operation will satisfy the guidelines of Appendix I to 10CFR50.

A listing of other relevant reference material is given in References 4 through 9.Class I and Class II Station structures are designed to withstand the effects of 100 mph winds at 30-feet above ground with a gust factor of 1.1. Structures and

systems which are necessary for a safe shutdown of the reactor and maintaining

a shutdown condition are designed to withstand tornado wind loadings of 300 mph.Bibliography:Rainfall Intensity - Duration - Frequency Curves, Tech. PaperNo. 25, U.S. Weather Bureau (1955) (Reference 23).

Climatological Data with Comparative Data, Minneapolis - St.Paul, Minnesota, 1953-1956 - U.S. Weather Bureau (2publications) (Reference 24).

Climatological Data with Comparative Data, St. Cloud,Minnesota 1953-1965 - U.S. Weather Bureau (2 publications)

(Reference 25).

Climatography of the United States, No. 86-17, Minnesota, U.S.Weather Bureau (Reference 26).

Local Climatological Data with Comparative Data, 1965 - U.S.Weather Bureau (Reference 27).

"Snow Load Studies", Housing Research Paper 19, Housingand Home Finance Agency, 1952 (Reference 28)."Glaze, Its Meteorology and Climatology, GeographicalDistribution and Economic Effects," Quartermaster Research and Engineering Center, 1959 (Reference 29).

Climatography of the United States No. 60-21, Minnesota - U.S.Weather Bureau (Reference 30).

Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 5 of 33 I/cahTable 2.3-1 Monthly Air Temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Maximum212438556877838072594026 Minimum3620354656615950392410 Mean 121529455766727061493218Extreme Maximum59618291105103107104105907563Extreme Minimum-38-34-30420334238228-18-29 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 6 of 33 I/cahTable 2.3-2 Summary of Precipitation Statistics Days with0.01ExtremeExtremeinchMonthlyMonthly*Max. inDays withorMeanMin.Max.24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months sThunder-Month more (inches)(inches)(inches)(inches)storms Dec90.77T2.481.05 0Jan80.780.022.821.900Feb 7 0.80 0.013.101.83 0 Winter242.35 - - -

0March101.320.113.952.00 1 April91.940.325.723.15 2 May 123.110.2010.005.00 5 Spring316.37 - - -

8 June134.060.879.783.35 8 July102.860.3112.344.80 7 Aug 10 2.83 0.318.994.62 6 Summer339.75 - - - 21 Sept92.920.249.243.65 4 Oct81.65.017.183.24 2 Nov 8 1.40.014.661.44 1 Fall255.97T - -

7 Annual11324.44*St. Cloud 1894-1965 T = TRACE Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 7 of 33 I/cahTable 2.3-3 Average Monthly Snowfall (inches) LocationJanFebMarAprMayJunJulAugSepOctNovDecAnnMinneapolis6.38.011.52.70.20.00.00.00.10.36.17.042.2 St. PaulSt. Cloud6.57.711.52.80.10.00.00.00.10.46.37.042.4 Maximum in 24 hours: Minneapolis 16.2 inches St. Cloud 12.2 inches Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 8 of 33 I/cahTable 2.3-4 Snow Load Data Wt. of EstimatedWt. of SeasonalMax. AccumulationSnowpack EqualledWt. of Maxon Grd plus Wt.

or Exceeded 1 YrSnowpackof Max. Possible Location in 10 of Record StormMinneapolis30 lb/ft 2 40 lb/ft 2 50 lb/ft 2St. Cloud30 lb/ft 2 40 lb/ft 2 50 lb/ft 2 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 9 of 33 I/cahTable 2.3-5 Wind Frequency Distributions at 10 Meter Level, Stability Class A (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN32034154076NNE4111120028 NE5172310046ENE9251300047E4181231038 ESE4243271068 SE42243240093 SSE313473270102S2183936260121SSW325602630117 SW22143100076 WSW52734181085 W32512154059WNW52134225087NW420512770109 NNW21037305084 VAR0000000Total Hours this Class1242Hours of Calm this Class6Percent of all Data this Class15.14 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 10 of 33 I/cahTable 2.3-6 Wind Frequency Distributions at 10 Meter Level, Stability Class B (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN171130022NNE06401011 NE14510011ENE0500005E0400004 ESE04411010 SE0421108 SSE15332014S35330014SSW22720013 SW42400010 WSW15510012 W0142007WNW17821019NW17963026 NNW18841022 VAR0000000Total Hours this Class208Hours of Calm this Class0Percent of all Data this Class2.54 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORTPage 11 of 33 I/cahTable 2.3-7 Wind Frequency Distributions at 10 Meter Level, Stability Class C (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN4141552040NNE171110020 NE27510015ENE011000011E1510007 ESE26611016 SE05822017 SSE07670020S15941121SSW06410112 SW281140025 WSW08601015 W07332015WNW241471028NW211221018 NNW081680032 VAR0000000Total Hours this Class313Hours of Calm this Class1Percent of all Data this Class 3.82 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 12 of 33 I/cahTable 2.3-8 Wind Frequency Distributions at 10 Meter Level, Stability Class D (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN378311862100310NNE1956551830151 NE2656611200155ENE247128100124E125847900126 ESE1375793400201 SE11631234060243 SSE1335801410143S1134532660130SSW8313684188 SW5232732060 WSW9182443058 W72820153078WNW5407229203169NW17379555251230 NNW2669170108140387 VAR0000000Total Hours this Class2753Hours of Calm this Class100Percent of all Data this Class 33.56 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 13 of 33 I/cahTable 2.3-9 Wind Frequency Distributions at 10 Meter Level, Stability Class E (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN289648700179NNE15391720073 NE19502130093ENE17301310061E14351910069 ESE136145200121 SE127049300134 SSE950381510113S1032332820105SSW1335412210112 SW15211850059 WSW152814110068 W18433020093WNW9101982200230NW1154873620190 NNW20871133340257 VAR0000000Total Hours this Class2008Hours of Calm this Class51Percent of all Data this Class 24.48 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 14 of 33 I/cahTable 2.3-10 Wind Frequency Distributions at 10 Meter Level, Stability Class F (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN2935200066NNE814200024 NE1814200034ENE149000023E1226000038 ESE1446600066 SE940650060 SSE1536922165S9291900057SSW1433820057 SW2025600051 WSW1839310061 W1837700062WNW1531000046NW17291000056 NNW14691100094 VAR0000000Total Hours this Class871Hours of Calm this Class11Percent of all Data this Class 10.62 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 15 of 33 I/cahTable 2.3-11 Wind Frequency Distributions at 10 Meter Level, Stability Class G (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN4323100067NNE167100024 NE1712000029ENE151000016E155000020 ESE1710000027 SE1814000032 SSE3530000065S3344600083SSW4935300087 SW3514000049 WSW3828000066 W3322000055WNW3211000043NW2619000045 NNW4130000071 VAR0000000Total Hours this Class808Hours of Calm this Class29Percent of all Data this Class 9.85 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 16 of 33 I/cahTable 2.3-12 Wind Frequency Distributions at 10 Meter Level, All Classes Combined (Hours at Each Wind Speed and Direction)(Page 1 of 2)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN14527822992160760NNE631401012340331NE881601171800383 ENE7915254200287E58151791310302ESE632261724530509 SE542182317590587 SSE7617618373131522S6916716297351531SSW891671596182486 SW831141092220330WSW86153863550365W791637637140369 WNW6921522682273622NW78167264126381674NNW104281355183240947 VAR0000000 Data Recovery Summary for PeriodTotal Hours 8784Hours of Calm 198Hours of Bad Data581 Percent Data Recovery93.39 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 17 of 33 I/cahTable 2.3-12 Wind Frequency Distributions at 10 Meter Level, All Classes Combined (Hours at Each Wind Speed and Direction)(Page 2 of 2)

Percent Acceptable Observations in Each Stability ClassClass A15.14Class B2.54 Class C3.82 Class D33.56Class E24.48Class F10.62 Class G9.85Average Wind Speed for Each Wind Category1 to 3 MPH2.44 to 7 MPH5.58 to 12 MPH9.7 13 to 18 MPH14.7 19 to 24 MPH20.5 Above 24 MPH25.8 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 18 of 33 I/cahTable 2.3-13 Wind Frequency Distributions at 100 Meter Level, Stability Class A (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN13976733NNE2300005 NE0101002ENE0220004E0001001 ESE067163234 SE0782413456 SSE01103221165S03102818766SSW03162316866 SW169166240 WSW0192418052 W038817339WNW11427419NW124117126 NNW015179133 VAR0000000Total Hours this Class656Hours of Calm this Class115Percent of all Data this Class7.98 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 19 of 33 I/cahTable 2.3-14 Wind Frequency Distributions at 100 Meter Level, Stability Class B (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN0415164039NNE045100019 NE031030016ENE13610011E0230005 ESE03722115 SE02833016 SSE011492127S05854123SSW121497134 SW141452026 WSW04655020 W05644322WNW02421514NW037811130 NNW041189032 VAR0000000Total Hours this Class349Hours of Calm this Class 0Percent of all Data this Class4.25 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 20 of 33 I/cahTable 2.3-15 Wind Frequency Distributions at 100 Meter Level, Stability Class C (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN0316152137NNE051320020 NE0224008ENE041100015E03921015 ESE08650019 SE04132010 SSE11953019S03712215SSW061374131 SW04461116 WSW04770018 W04453117WNW231175735NW1312214445 NNW31110104341 VAR0000000Total Hours this Class361Hours of Calm this Class0Percent of all Data this Class4.39 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 21 of 33 I/cahTable 2.3-16 Wind Frequency Distributions at 100 Meter Level, Stability Class D (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN17468412010149417NNE15384567193187 NE10213637186128ENE636603441141E10455125125148 ESE123959564415225 SE927511306920306 SSE43051762614201S71550601811161SSW11254039327154 SW6222528168105 WSW61717339789 W52715221815102WNW132647614841236NW823521009563341 NNW10459015112082498 VAR0000000Total Hours this Class3504Hours of Calm this Class 65Percent of all Data this Class42.64 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 22 of 33 I/cahTable 2.3-17 Wind Frequency Distributions at 100 Meter Level, Stability Class E (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN21636805412200NNE1122051171102 NE212202912378ENE01242197181E5735307084 ESE410213920397 SE082561324130 SSE292776405159S21430363618136SSW1423435220143 SW281020537100 WSW318172022282 W213212918386WNW263166554164NW2142975502172 NNW31531686711195 VAR0000000Total Hours this Class2032Hours of Calm this Class 23Percent of all Data this Class24.73 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 23 of 33 I/cahTable 2.3-18 Wind Frequency Distributions at 100 Meter Level, Stability Class F (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN39142718273NNE05171613051 NE1622137150ENE0621140041E2613183042 ESE069187141 SE28122218062 SSE25133021374S2883012767SSW0292133267 SW1284230083 WSW28101923567 W16171410149WNW38173711177NW41022335074 NNW51422374082 VAR0000000Total Hours this Class1000Hours of Calm this Class0Percent of all Data this Class12.17 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 24 of 33 I/cahTable 2.3-19 Wind Frequency Distributions at 100 Meter Level, Stability Class G (Hours at Each Wind Speed and Direction)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN07852022NNE021472025 NE13762019ENE13910014E02560013 ESE03350011 SE00883019 SSE35252017S0232007SSW025111019 SW081377035 WSW341134126 W031362024WNW031154023NW26890025 NNW15522217 VAR0000000Total Hours this Class316Hours of Calm this Class0Percent of all Data this Class3.85 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 25 of 33 I/cahTable 2.3-20 Wind Frequency Distributions at 100 Meter Level, All Classes Combined (Hours at Each Wind Speed and Direction)(Page 1 of 2)

Wind Speed (MPH)

WINDDIRECTION1-34-78-1213-1819-24>24TOTALN238818227018771821NNE1869114153514409 NE144897933910301ENE86615169112307E176511682235308 ESE16751121417622442 SE115611325114028599 SSE125212623311524562S11501161629046475SSW134412015314539514 SW11548312411518405 WSW1456771118115354 W86184887226339WNW214912518013162568NW186113425717271713 NNW229517429321599898 VAR0000000

Data Recovery Summary for PeriodTotal Hours8784Hours of Calm 203Hours of Bad Data566 Percent Data Recovery93.56 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 26 of 33 I/cahTable 2.3-20 Wind Frequency Distributions at 100 Meter Level, All Classes Combined (Hours at Each Wind Speed and Direction)(Page 2 of 2)

Percent Acceptable Observations in Each Stability ClassClass A7.98Class B4.25 Class C4.39 Class D42.64Class E24.73Class F12.17 Class G3.85Average Wind Speed for Each Wind Category1 to 3 MPH2.64 to 7 MPH5.78 to 12 MPH10.2 13 to 18 MPH15.5 19 to 24 MPH21.1 Above 24 MPH28.2 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 27 of 33 I/cahTable 2.3-21 Maximum Wind Velocity Month Speed, MPH DirectionYear Jan 47 NW 1928Feb52NW1952March56SW1920 April58N1912 May61NW1964 June63NW1939July92*W1951August57NW1922 September50NW1921 October73S1949 November60SW1959December52W1946*Associated with the July 20, 1951 tornado Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 28 of 33 I/cahTable 2.3-22 Annual Average Dispersion Factor (X/Q) - Reactor Building Vent ReleasesReactor Building VentNo Decay, Undepleted Corrected for Open Terrain RecirculationAnnual Average CHI/Q (Sec/Meter Cubed)Distance in MilesSector0.2500.5000.7501.0001.5002.0002.5003.0003.5004.0004.500S6.345E-062.532E-061.812E-061.206E-067.098E-074.539E-073.211E-072.736E-072.433E-072.106E-071.864E-07SSW2.742E-061.163E-068.628E-075.724E-073.233E-072.500E-072.108E-071.543E-071.192E-071.011E-078.773E-08SW2.985E-061.246E-069.472E-076.498E-073.851E-073.108E-072.672E-072.090E-071.704E-071.497E-071.320E-07WSW1.949E-068.250E-076.662E-074.821E-073.037E-072.462E-072.106E-071.548E-071.198E-071.071E-079.643E-08W2.393E-069.695E-077.325E-075.018E-073.014E-072.422E-072.084E-071.631E-071.329E-071.061E-078.733E-08WNW4.552E-061.768E-061.247E-068.060E-074.532E-073.477E-072.900E-072.393E-072.020E-071.594E-071.300E-07NW5.502E-062.094E-061.399E-068.565E-074.435E-072.855E-072.046E-071.688E-071.459E-071.235E-071.071E-07NNW4.704E-061.698E-061.112E-066.930E-073.859E-072.493E-071.796E-071.386E-071.121E-079.375E-088.041E-08N5.225E-061.822E-061.133E-066.806E-073.661E-072.315E-071.643E-071.347E-071.163E-079.604E-088.136E-08NNE4.357E-061.489E-069.479E-075.946E-073.437E-072.255E-071.642E-071.275E-071.035E-078.665E-077.431E-08NE2.523E-069.147E-075.967E-073.771E-072.148E-071.592E-071.290E-071.011E-078.234E-086.909E-085.929E-08ENE3.074E-061.035E-066.587E-074.245E-072.560E-071.829E-071.424E-071.119E-079.141E-087.688E-086.611E-08E3.142E-061.104E-067.441E-074.922E-072.963E-071.999E-071.471E-071.146E-079.290E-087.763E-086.638E-08ESE5.744E-062.195E-061.425E-068.550E-074.320E-072.693E-071.880E-071.411E-071.112E-079.091E-087.636E-08SE6.575E-062.438E-061.529E-068.966E-074.458E-072.949E-072.192E-071.638E-071.287E-071.049E-078.790E-08SSE9.467E-063.635E-062.343E-061.395E-067.007E-074.363E-073.045E-072.284E-071.801E-071.473E-071.239E-07Annual Average CHI/Q (Sec/Meter Cubed)Distance in MilesSector5.0007.50010.00015.00020.00025.00030.00035.00040.00045.00050.000S1.584E-078.944E-086.152E-083.795E-082.685E-082.049E-081.641E-081.359E-081.155E-089.997E-098.787E-09SSW7.398E-084.073E-082.760E-081.673E-081.170E-088.858E-097.051E-095.812E-094.916E-094.241E-093.715E-09SW1.104E-075.913E-083.946E-082.349E-081.626E-081.223E-089.682E-097.949E-096.701E-095.765E-095.040E-09WSW8.102E-084.410E-082.971E-081.787E-081.244E-089.379E-097.442E-096.118E-095.163E-094.445E-093.888E-09W7.362E-084.039E-082.729E-081.647E-081.150E-088.698E-096.922E-095.706E-094.827E-094.165E-093.650E-09WNW1.087E-075.814E-083.870E-082.297E-081.588E-081.194E-089.459E-097.772E-096.557E-095.645E-094.939E-09 NW9.039E-074.975E-083.367E-082.037E-081.424E-081.079E-088.595E-097.093E-096.006E-095.187E-094.550E-09NNW6.954E-084.177E-082.987E-081.936E-081.413E-081.103E-088.994E-097.559E-086.498E-095.684E-095.041E-09N7.033E-084.216E-083.010E-081.946E-081.419E-081.108E-089.028E-097.587E-096.523E-095.706E-095.061E-09NNE6.492E-084.041E-082.954E-081.967E-081.461E-081.155E-089.510E-098.057E-096.972E-096.134E-095.467E-09NE5.180E-083.212E-082.336E-081.544E-081.141E-088.987E-097.377E-096.234E-095.384E-094.728E-094.207E-09ENE5.786E-083.612E-082.639E-081.753E-081.298E-081.024E-088.412E-097.113E-096.146E-095.398E-094.805E-09E5.781E-083.546E-082.563E-081.681E-081.236E-089.700E-097.940E-096.694E-095.770E-095.058E-094.495E-09ESE6.554E-083.835E-082.701E-081.722E-081.248E-089.695E-097.881E-096.611E-095.675E-094.959E-094.394E-09SE7.530E-084.381E-083.074E-081.947E-081.401E-081.082E-088.747E-097.302E-096.241E-095.432E-094.797E-09SSE1.065E-076.296E-084.487E-082.923E-082.100E-081.621E-081.317E-081.105E-089.685E-098.630E-097.607E-09 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 29 of 33 I/cahTable 2.3-23 Annual Average Dispersion Factor (X/Q) - Plant Stack ReleasesOffgas StackNo Decay, Undepleted Corrected for Open Terrain RecirculationAnnual Average CHI/Q (Sec/Meter Cubed)Distance in MilesSector0.2500.5000.7501.0001.5002.0002.5003.0003.5004.0004.500S2.115E-074.610E-072.388E-071.593E-071.288E-079.864E-087.790E-086.894E-086.157E-085.380E-084.765E-08SSW2.837E-077.831E-073.300E-071.700E-071.106E-079.136E-087.844E-086.159E-085.017E-084.336E-083.810E-08SW1.845E-083.655E-083.938E-083.921E-083.866E-084.136E-084.103E-083.536E-083.093E-082.878E-082.690E-08WSW2.433E-084.174E-084.948E-084.936E-084.708E-084.665E-084.328E-083.408E-082.772E-082.516E-082.304E-08W5.617E-092.206E-083.707E-084.484E-085.007E-085.511E-085.516E-084.752E-084.142E-083.487E-082.990E-08WNW1.006E-076.505E-086.450E-086.468E-086.394E-086.555E-086.264E-085.602E-085.023E-084.155E-083.514E-08NW1.418E-076.927E-085.869E-085.975E-085.870E-085.118E-084.319E-083.917E-083.548E-083.103E-082.750E-08NNW1.477E-078.592E-086.979E-086.209E-085.752E-084.724E-083.884E-083.244E-082.757E-082.381E-082.085E-08N1.476E-078.231E-086.138E-085.204E-084.793E-083.936E-083.252E-082.897E-082.597E-082.233E-081.949E-08NNE1.582E-071.080E-078.621E-086.771E-085.532E-084.327E-083.479E-082.873E-082.427E-082.089E-081.825E-08NE2.384E-074.483E-071.951E-079.784E-085.879E-084.452E-083.628E-082.946E-082.468E-082.114E-081.844E-08ENE1.202E-077.218E-085.321E-083.986E-083.219E-082.775E-082.422E-082.069E-081.795E-081.577E-081.402E-08E9.542E-086.545E-085.063E-083.953E-083.280E-082.701E-082.253E-081.910E-081.645E-081.437E-081.271E-08ESE1.608E-074.092E-071.913E-071.103E-077.750E-085.977E-084.803E-083.978E-083.375E-082.917E-082.560E-08SE1.908E-074.410E-072.167E-071.285E-078.914E-087.234E-086.044E-084.895E-084.075E-083.467E-083.003E-08SSE8.598E-089.415E-081.104E-071.062E-079.305E-087.625E-086.228E-085.167E-084.366E-083.751E-083.271E-08Annual Average CHI/Q (Sec/Meter Cubed)Distance in MilesSector5.0007.50010.00015.00020.00025.00030.00035.00040.00045.00050.000S4.135E-082.465E-081.726E-081.073E-087.580E-095.763E-094.597E-093.794E-093.211E-092.771E-092.428E-09SSW3.303E-081.972E-081.388E-088.722E-096.223E-094.774E-093.840E-093.193E-092.721E-092.363E-092.082E-09SW2.325E-081.368E-089.507E-095.853E-094.106E-093.106E-092.467E-092.029E-091.712E-091.474E-091.288E-09WSW1.978E-081.140E-087.837E-094.777E-093.339E-092.521E-092.001E-091.645E-091.387E-091.194E-091.043E-09W2.603E-081.561E-081.093E-086.765E-094.750E-093.590E-092.848E-092.339E-091.970E-091.692E-091.477E-09WNW3.025E-081.750E-081.201E-087.268E-095.039E-093.775E-092.976E-092.431E-092.039E-091.746E-091.519E-09 NW2.380E-081.405E-089.773E-096.016E-094.216E-093.185E-092.527E-092.076E-091.750E-091.504E-091.313E-09NNW1.836E-081.147E-088.248E-095.287E-093.804E-092.929E-092.359E-091.961E-091.669E-091.448E-091.274E-09N1.724E-081.091E-087.886E-095.067E-093.640E-092.795E-092.244E-091.859E-091.578E-091.365E-091.197E-09NNE1.616E-081.027E-087.432E-094.768E-093.419E-092.619E-092.099E-091.736E-091.471E-091.271E-091.114E-09NE1.633E-081.048E-087.707E-095.102E-093.756E-092.945E-092.407E-092.027E-091.745E-091.528E-091.357E-09ENE1.259E-088.389E-096.250E-094.166E-093.064E-092.394E-091.948E-091.633E-091.400E-091.221E-091.079E-09E1.136E-097.459E-095.508E-093.633E-092.653E-092.062E-091.671E-091.396E-091.193E-091.038E-099.153E-10ESE2.276E-081.471E-081.080E-087.091E-095.173E-094.020E-093.258E-092.723E-092.328E-092.026E-091.789E-09SE2.640E-081.648E-081.188E-087.676E-095.564E-094.310E-093.490E-092.915E-092.493-092.170E-091.917E-09SSE2.889E-081.823E-081.318E-088.505E-096.071E-094.643E-093.728E-093.091E-092.651E-092.316E-092.028E-09 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 30 of 33 I/cahTable 2.3-24 Relative Deposition per Unit Area (D/Q) - Reactor Building Vent ReleasesReactor Building VentCorrected for Open Terrain Recirculation Relative Deposition per Unit Area (M**-2) at Fixed Points by Downwind Sectors Distance in Miles Sector0.250.500.751.001.502.002.503.003.504.004.50S8.092E-083.151E-081.761E-088.946E-093.746E-091.900E-091.135E-097.688E-105.686E-104.375E-103.536E-10SSW3,154E-081.295E-087.461E-093.869E-091.609E-098.979E-105.352E-103.563E-102.567E-101.965E-101.583E-10SW3.300E-081.377E-087.966E-094.147E-091.735E-099.762E-105.841E-103.907E-102.836E-102.443E-102.629E-10WSW2.055E-089.475E-095.706E-093.047E-091.281E-097.625E-104.563E-103.047E-102.200E-101.693E-101.459E-10W2.502E-081.056E-086.179E-093.225E-091.349E-097.579E-104.517E-103.013E-102.184E-101.685E-101.366E-10WNW5.235E-082.088E-081.177E-085.991E-092.437E-091.320E-097.849E-105.228E-104.494E-103.415E-102.717E-10NW6.974E-082.703E-081.504E-087.583E-092.914E-091.492E-099.284E-106.290E-104.606E-103.515E-102.816E-10NNW6.209E-082.360E-081.286E-086.399E-092.543E-091.281E-097.729E-105.142E-103.680E-102.787E-102.281E-10N7.209E-082.676E-081.434E-087.046E-092.712E-091.364E-098.121E-105.491E-104.003E-103.078E-102.480E-10NNE5.609E-082.149E-081.150E-085.643E-092.168E-091.092E-096.510E-104.314E-103.073E-102.310E-101.807E-10NE3.345E-081.350E-087.297E-093.601E-091.354E-096.904E-104.220E-102.798E-101.994E-101.498E-101.171E-10ENE3.671E-081.447E-087.753E-093.811E-091.429E-097.286E-104.441E-102.946E-102.098E-101.573E-101.227E-10E3.616E-081.380E-087.441E-093.674E-091.383E-097.040E-104.220E-102.802E-101.993E-101.490E-101.157E-10ESE7.702E-082.887E-081.555E-087.653E-092.863E-091.450E-098.654E-105.727E-104.064E-103.034E-102.352E-10SE9.530E-083.536E-081.903E-089.380E-093.520E-091.787E-091.108E-097.322E-105.211E-103.917E-103.070E-10SSE1.223E-074.534E-082.479E-081.237E-084.704E-092.399E-091.438E-099.546E-106.786E-105.068E-103.929E-10 Distance in Miles Sector5.007.5010.0015.0020.0025.0030.0035.0040.0045.0050.00S2.971E-101.641E-101.127E-106.546E-114.158E-112.793E-111.993E-111.486E-111.148E-119.147E-127.448E-12SSW1.323E-107.175E-114.870E-112.806E-111.782E-111.201E-118.596E-126.434E-124.986E-123.982E-123.250E-12SW2.105E-109.662E-115.959E-113.100E-111.909E-111.291E-119.317E-127.044E-125.505E-124.427E-123.634E-12WSW1.213E-106.451E-114.329E-112.471E-111.570E-111.062E-117.637E-125.741E-124.466E-123.580E-122.930E-12W1.154E-106.493E-114.495E-112.636E-111.680E-111.129E-118.061E-126.013E-124.646E-123.701E-123.013E-12WNW2.243E-101.166E-107.775E-114.381E-112.752E-111.845E-111.315E-119.804E-127.573E-126.024E-124.898E-12 NW2.345E-101.257E-108.501E-114.874E-113.086E-112.075E-111.483E-111.109E-118.579E-126.843E-125.578E-12NNW1.892E-109.973E-116.677E-113.794E-112.401E-111.623E-111.168E-118.812E-126.897E-125.559E-124.588E-12N2.073E-101.125E-107.670E-114.423E-112.805E-111.887E-111.349E-111.008E-117.817E-126.237E-125.088E-12NNE1.461E-106.935E-114.359E-112.340E-111.477E-111.024E-117.634E-125.990E-124.874E-124.079E-123.502E-12NE9.447E-114.440E-112.767E-111.482E-119.433E-126.640E-125.023E-123.996E-123.291E-122.782E-122.410E-12ENE9.867E-114.581E-112.835E-111.505E-119.545E-126.726E-125.108E-124.086E-123.391E-122.886E-122.519E-12E9.243E-114.165E-112.516E-111.293E-118.073E-125.669E-124.320E-123.483E-122.928E-122.518E-122.228E-12ESE1.878E-108.431E-115.083E-112.596E-111.690E-111.118E-118.386E-126.635E-125.466E-124.613E-123.999E-12SE2.489E-101.199E-107.608E-114.100E-112.565E-111.747E-111.273E-119.745E-127.737E-126.321E-125.291E-12SSE3.136E-101.405E-108.434E-115.267E-113.273E-112.225E-111.622E-111.342E-111.457E-111.291E-111.047E-11 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 31 of 33 I/cahTable 2.3-25 Relative Deposition per Unit Area (D/Q) - Plant Stack ReleasesOffgas StackCorrected for Open Terrain Recirculation Relative Deposition per Unit Area (M**-2) at Fixed Points by Downwind Sectors Distance in Miles Sector0.250.500.751.001.502.002.503.003.504.004.50S8.898E-097.159E-095.968E-094.054E-091.953E-091.193E-098.045E-105.771E-104.319E-103.739E-103.038E-10SSW5.688E-094.432E-093.478E-092.236E-091.025E-096.119E-104.918E-103.371E-102.454E-101.925E-101.510E-10SW1.821E-091.550E-091.419E-091.038E-095.308E-103.322E-102.875E-102.048E-101.483E-101.123E-108.902E-11WSW2.098E-091.769E-091.596E-091.155E-095.895E-103.655E-103.111E-102.140E-101.561E-101.241E-109.717E-11W1.487E-091.348E-091.350E-091.050E-095.609E-103.570E-103.036E-102.255E-101.633E-101.236E-109.681E-11WNW4.723E-093.809E-093.189E-092.174E-091.051E-096.427E-105.445E-103.870E-102.798E-102.117E-101.658E-10NW5.707E-094.661E-093.991E-092.772E-091.361E-098.380E-105.676E-104.081E-103.058E-102.692E-102.172E-10NNW7.648E-095.852E-094.428E-092.743E-091.212E-097.115E-104.696E-103.330E-102.477E-101.909E-101.511E-10N7.157E-095.428E-094.032E-092.450E-091.060E-096.161E-104.043E-102.858E-102.122E-101.634E-101.294E-10NNE8.998E-096.737E-094.863E-092.863E-091.196E-096.828E-104.434E-103.115E-102.307E-101.774E-101.404E-10NE6.944E-095.171E-093.688E-092.141E-098.802E-104.980E-103.217E-102.254E-101.666E-101.280E-101.013E-10ENE6.176E-094.591E-093.263E-091.885E-097.710E-104.350E-102.805E-101.963E-101.451E-101.115E-108.822E-11E5.361E-094.032E-092.939E-091.749E-097.403E-104.253E-102.773E-101.952E-101.447E-101.113E-108.813E-11ESE6.035E-094.770E-093.848E-092.538E-091.192E-097.196E-104.824E-103.449E-102.577E-101.989E-101.575E-10SE8.324E-096.599E-095.355E-093.552E-091.676E-091.014E-096.806E-104.870E-103.640E-102.810E-102.225E-10SSE7.413E-096.241E-095.616E-094.058E-092.056E-091.282E-098.739E-106.305E-104.732E-103.660E-102.897E-10 Distance in Miles Sector5.007.5010.0015.0020.0025.0030.0035.0040.0045.0050.00S2.446E-101.114E-106.564E-113.308E-112.074E-111.466E-111.116E-118.927E-127.412E-126.290E-125.463E-12SSW1.217E-105.567E-113.292E-111.671E-111.053E-117.563E-125.836E-124.727E-123.969E-123.402E-122.986E-12SW7.162E-113.229E-111.879E-119.304E-125.797E-124.085E-123.138E-122.557E-122.174E-121.890E-121.690E-12WSW7.819E-113.531E-112.059E-111.022E-116.374E-124.485E-123.431E-122.776E-122.342E-122.020E-121.790E-12W7.788E-113.515E-112.044E-111.009E-116.253E-124.377E-123.335E-122.694E-122.270E-121.959E-121.739E-12WNW1.335E-106.042E-113.541E-111.776E-111.113E-117.835E-125.961E-124.770E-123.971E-123.378E-122.942E-12 NW1.748E-107.937E-114.658E-112.335E-111.460E-111.028E-117.816E-126.248E-125.191E-124.410E-123.837E-12NNW1.222E-105.853E-113.613E-111.925E-111.225E-118.921E-126.812E-125.396E-124.378E-123.623E-123.046E-12N1.047E-105.019E-113.102E-111.657E-111.056E-117.732E-125.931E-124.702E-123.821E-123.165E-122.663E-12NNE1.137E-105.462E-113.383E-111.817E-111.163E-118.582E-126.621E-125.270E-124.294E-123.563E-123.002E-12NE8.210E-113.948E-112.448E-111.318E-118.450E-126.265E-124.847E-123.865E-123.153E-122.619E-122.207E-12ENE7.148E-113.439E-112.133E-111.149E-117.373E-125.474E-124.239E-123.382E-122.760E-122.293E-121.933E-12E7.135E-113.425E-112.120E-111.136E-117.261E-125.343E-124.113E-123.269E-122.661E-122.207E-121.858E-12ESE1.273E-106.078E-113.740E-111.979E-111.252E-118.999E-126.821E-125.363E-124.333E-123.575E-123.000E-12SE1.797E-108.583E-115.280E-112.792E-111.765E-111.268E-119.605E-127.548E-126.096E-125.029E-124.219E-12SSE2.339E-101.114E-106.831E-113.586E-112.255E-111.598E-111.200E-119.368E-127.532E-126.193E-125.185E-12 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 32 of 33 I/cahTable 2.3-26 Site Boundary X/Q and D/Q - Reactor Building Vent ReleasesReactor Building VentCorrected for Open Terrain Recirculation Specific Points of InterestReleaseType ofSector Distance X/Q X/Q X/Q D/Q IDLocation(Miles)(Meters)(Sec/Cub Meter)(Sec/Cub Meter)(Sec/Cub Meter)(Per Sq Meter)

No Decay 2.260 Day Decay 8.000 Day Decay______________________________________ Undepleted Undepleted Depleted

_____________ RSite BoundaryS0.34547.4.04E-064.03E-063.79E-065.36E-08 RSite BoundarySSW0.32515.1.92E-061.92E--061.813-062.31E-08 RSite BoundarySW0.32515.2.05E-062.05E-061.93E-062.43E-08 RSite BoundaryWSW0.35563.1.17E-061.17E-061.11E-061.43E-08 RSite BoundaryW0.48772.9.97E-079.96E-079.31E-071.11E-08 RSite BoundaryWNW0.681094.1.33E-061.33E-061.24E-061.36E-06 RSite BoundaryNW0.43692.2.49E-062.49E-062.32E-063.34E-08 RSite BoundaryNNW0.53853.1.57E-061.57E-061.45E-062.17E-08 RSite BoundaryN0.51821.1.76E-061.75E-061.62E-062.60E-08 RSite BoundaryNNE0.58933.1.23E-061.22E-061.13E-061.72E-08 RSite BoundaryNE0.651046.6.74E-076.73E-076.26E-079.13E-09 RSite BoundaryENE0.831336.5.55E-075.53E-075.14E-076.05E-09 RSite BoundaryE0.59950.9.09E-079.08E-078.39E-071.08E-08 RSite BoundaryESE0.59950.1.81E-061.80E-061.67E-062.25E-08 RSite BoundarySE0.61982.1.91E-061.91E-061.75E-062.62E-08 RSite BoundarySSE0.43692.4.38E-064.38E-064.06E-065.65E-08 Revision 25 USAR 2.3MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 33 of 33 I/cahTable 2.3-27 Site Boundary X/Q and D/Q -Plant Stack ReleasesOffgas StackCorrected for Open Terrain Recirculation Specific Points of InterestReleaseType ofSector Distance X/Q X/Q X/Q D/Q IDLocation(Miles)(Meters)(Sec/Cub Meter)(Sec/Cub Meter)(Sec/Cub Meter)(Per Sq Meter)

No Decay 2.260 Day Decay 8.000 Day Decay______________________________________ Undepleted Undepleted Depleted

_____________ OSite BoundarySSW0.31499.6.50E-076.44E-076.48E-075.48E-09 OSite BoundarySW0.33531.2.96E-082.96E-082.96E-081.75E-09 OSite BoundarySW0.33531.2.96E-082.96E-082.96E-081.75E-09 OSite BoundaryWSW0.38612.3.54E-083.54E-083.54E-081.94E-09 OSite BoundaryW0.56901.2.49E-082.49E-082.46E-081.33E-09 OSite BoundaryNW0.781255.5.70E-085.69E-085.61E-083.83E-09 OSite BoundaryNW0.53853.5.93E-085.92E-085.86E-084.55E-09 OSite BoundaryNNW0.61982.7.02E-087.02E-086.92E-085.12E-09 OSite BoundaryN0.59950.6.60E-086.60E-086.51E-084.83E-09 OSite BoundaryN0.631014.6.33E-086.32E-086.23E-084.60E-09 OSite BoundaryNNE0.651046.8.84E-088.83E-088.68E-085.49E-09 OSite BoundaryENE0.781255.4.96E-084.96E-084.86E-083.05E-09 OSite BoundaryE0.50805.6.12E-086.11E-086.06E-084.03E-09 OSite BoundaryESE0.50805.3.42E-073.37E-073.37E-074.77E-09 OSite BoundarySSE0.51821.9.11E-089.10E-089.02E-086.20E-09 OSite BoundaryS0.36579.4.78E-074.74E-074.77E-078.24E-09 MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 SECTION 2 SITE AND ENVIRONS Revision 32 Page 1 of 6 2.4 Hydrology 2.4.1 Surface Water The Monticello sites lies about one-third of the river distance from Elk River, Minnesota to St. Cloud, Minnesota. Stream flow records of the Mississippi were kept at Elk River by the U.S. Geological Survey. The gauging station at Elk River was about 2500 feet downstream from the confluence of the Elk River (the only significant river entering the Mississippi River between the cities of Elk River and St. Cloud) and the Mississippi River. The Elk River Station has closed and the U.S. Geological Survey established a gauging station on the Mississippi River at St. Cloud in 1989. In Table 2.4-1, the number of years of record, the average annual flow, the minimum recorded flow, the maximum recorded flow at each gauging station are tabulated. From this data, and with information on Elk River flows, the following flow statistics are estimated for the Mississippi River at the Monticello site: Average Flow - 4600 ft 3/sec Minimum Flow - 240 ft 3/sec Maximum Flow - 51,000 ft 3/sec The average velocity of flow at the site varies between 1.5 to 2.5 ft/sec for flows below 10,000 cfs. Figure 2.4-1 is a flow duration curve for the Mississippi River at St. Cloud. From this curve, the flow at Monticello is expected to exceed 1100 ft 3/sec 90% of the time, and 300 ft 3/sec 99% of the time. Based on past temperature records from the Whitney Steam Plant at St. Cloud (since retired and removed) the average river temperature for these summer months is 71° F. Because of possible low stream flow conditions, and high natural river water temperatures, two cooling towers are included in the plant design in order to meet the standards of the Minnesota Pollution Control Agency. At times of extremely low flow, the plant operates on a closed cycle and the makeup requirement of about 54 ft 3/sec is withdrawn from the river. At times of substantial flow and high ambient river temperature conditions, the cooling tower may be employed to control the temperature of discharged water. All existing cooling towers are operated whenever the ambient river temperature measured at some point unaffected by the planabove 20°C (68°F), except in the event the cooling towers are out of service due to equipment failure or performance of maintenance to prevent equipment failure.

MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 Revision 32 Page 2 of 6 The spring flood of 1965 exceeds all flood flows on record to date. Figure 2.4-2 shows the location of three flood stage boards which recorded this record flood. The stage at the site was about 916 ft msl for an estimated flow of 51,000

ft 3/sec. Figure 2.4-3 shows the results of a flood frequency study. The 1000 year flood has an estimated stage of 920 ft msl. A study was made by the Harza Engineering Company to determine the predicted flood discharge flow and flood level at the site resulting from the maximum probable flood as defined by the U.S. Army Corps of Engineers (Policies and Procedures Pertaining to Determination of Spillway Capacities and Freeboard Allowances for Dams, Engineer Circular No. 1110-2-27, Enclosure 2, August 1, 1966 (Reference 33), Department of the Army, Office of the Chief of Engineers). Refer to Appendix G. The probable maximum discharge was determined to be 364,900 ft 3/sec and to have a corresponding peak stage of elevation 939.2 ft msl. The flood would result from meteorological conditions which could occur in the spring and would reach maximum river level in about 12 days. It was estimated the flood stage would remain above elevation 930.0 ft msl. for approximately 11 days. The normal river stage at the plant site is about 905 ft msl. At a distance 1-1/2 mile upstream, the normal river elevation is about 910 ft msl, and at an equal distance downstream, the river is at 900 ft msl. Thus, the hydraulic slope is about 3-1/3 ft/mile. 2.4.2 Public Water Supplies 2.4.2.1 Surface Water The nearest domestic water supply reservoir with a free surface open to the air is the Minneapolis Water Works Reservoir. This reservoir is located north o f Minneapolis, and is about 37 miles from the site. St. Paul uses a chain of lakes in its water supply system. These lakes, located north of St. Paul, are about 40 miles from the site. The major supply of water for these reservoirs is the Mississippi River. The St. Paul intake is about 33 river miles from the site and the Minneapolis intake is about 37 miles from the site. Harza Engineering Company made a study of pollutant dispersion of a slug waste in the river (Reference 35) between the Monticello Plant site and the Minneapolis and St. Paul water intakes. The results of this study were given in Answer to Question 3.3 of Amendment 4 and all of Amendment 8 of the Monticello Facility Description and Safety Analysis Report.

MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 Revision 32 Page 3 of 6 In the event of a contaminated Mississippi River, the Minneapolis water supply would be more critical than the St. Paul water supply, because Minneapolis has about a 2 day water supply and St. Paul a 4+week supply. Under the emergency, withdrawal of river water for the Minneapolis system could be suspended for about 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months without curtailment of non-essential use. This period could be extended to about 100 hours0.00116 days 0.0278 hours 1.653439e-4 weeks 3.805e-5 months if non-essential use is curtailed. Between 1960 and 1980, recreational use of the reach of river near Monticello has increased significantly. River water is used for irrigation in a limited way between the site and Minneapolis. Twenty-six water appropriation permits have been issued by the Minnesota Department of Natural Resources for this reach of the river. At Elk River, the river water is used for cooling purposes for an electric generating plant. The next industrial water user is Xcel Energy in north Minneapolis. 2.4.2.2 Ground Water The outwash drift on both sides of the Mississippi in general yields large quantities of water. The water table under normal circumstances is higher than the river, thus ground water as well as run-off from rainfall feeds the river. The drift water usually is quite hard containing calcium, magnesium, and bicarbonates, with small amounts of sodium, potassium, sulfates, and chlorides. Between the plant site and Minneapolis, the cities of Monticello, Elk River, Anoka, Coon Rapids, Champlin, Brooklyn Center, Brooklyn Park, and Fridley obtain groundwater from the bedrock formations for their domestic water supply as of 1981. Numerous shallow wells supply water for residences and farms along the river terrace. The closest public water supply wells are the city of Monticello wells. These wells are 16 inches in diameter and 250 feet deep. The 1200 gpm capacity is limited by the installed pumps. The wells have been tested to 2000 gpm. They are located in the main part of the city of Monticello. The wells which obtain their water from the drift are recharged by local precipitation, while the wells which withdraw water from the bedrock are recharged by precipitation where the bedrock is at or near the land surface. The largest increment of recharge occurs during the spring thaw. g site ranges from about 908 ft. msl to about 942 ft. msl, with the site itself at approximately 908 ft. msl. Since the normal river is at about 905 ft msl, groundwater flow is to the river. This usual case of groundwater flow to the river may not exist during floods.

MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 Revision 32 Page 4 of 6 2.4.3 Plant Design Bases Dependent on Hydrology Water movements passing the site are subject to large variations in the course of a year. Plant design with respect to operation and liquid waste disposal takes into account large variations in water flow from less than 200 ft 3/sec to flood level up to plant grade (about 930ft msl) which is well above record historical floods. 2.4.4 Water Use Permits and Appropriations Relevant to Plant Operation The ground and surface water appropriations are pursuant to permits issued by the Minnesota Department of Natural Resources. The requirements for groundwater include domestic use for over 25 persons, industrial use to seal pumps in the plant intake structure and plant make up water. River water is required for condenser cooling, service water cooling, and plant makeup. 2.4.5 Surface Water Quality Water samples were taken upstream, downstream and at the plant discharge on February 28, 1972.

The chemical analyses of the samples were as follows: Upstream Downstream Plant Mississippi Mississippi Discharge P Alkalinity - ppm CaCO3 0 0 0 M Alkalinity - ppm CaCO3 170 169 165 Ammonia Nitrogen - ppm N 0.05 0.02 0.02 Organic Nitrogen - ppm N 0.933 0.61 0.65 Nitrate Nitrogen - ppm N 0.28 0.37 0.37 Nitrite Nitrogen - ppm N 0.001 0.003 0.002 Chloride - ppm 1.4 0.9 1.0 Sulfate - ppm SO4 7.8 6.6 7.3 Color - Units 35 35 35 Turbidity - JTU 3.9 2.0 2.5 Total Hardness - ppm CaCO3 177 178 178 Calcium Hardness - ppm CaCO3 122 114 122 pH 7.5 7.9 7.8 Total Solids - ppm 288 272 247 Non-Filterable Solids - ppm 12 3 5 Dissolved Solids - ppm 276 269 242 MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 Revision 32 Page 5 of 6 Upstream Downstream Plant Mississippi Mississippi Discharge Fixed Non-Filterable Solids - ppm 8 2 3 Volatile Solids - ppm 4 1 2 Total Soluble Phosphorus - ppm P 0.035 0.026 0.024 Total Chlorophyll - mg/m 3 5.7 1.5 1.6 Conductivity - mmhos (25° C) 364 357 364 Temp. °C 0.2 8.3 15.5 D.O. mg/l 8.4 8.6 8.2 BOD mg/l 0.9 1.0 0.9 Cooling towers not operating Paper pulp (Sartell and Little Falls) facilities were located upstream of the plant when the study was done. Sewage treatment facilities (St. Cloud and others) are located upstream of the plant. 2.4.6 Environmental Assessment An environmental assessment (EA) of MNGP operation at Extended Power Uprate (EPU) conditions was submitted to the NRC (Reference 45, Enclosure 4). The assessment was subsequently updated by Reference 47. Approval of the updated EA was completed in May 2013 (Reference 46). The assessment includes the environmental effect of plant water use and cooling tower operation at EPU conditions.

01101248 01101248 MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-02.04 Revision 32 Page 6 of 6 Table 2.4-1 Mississippi River Flows at Elk River and St. Cloud, Minnesota Location Elk River 1 St. Cloud 2 Number of Records, years 38 40 Average Annual Flow, ft 3/sec 5,260 4,360 Minimum Recorded Flow, ft 3/sec 278 220 Maximum Recorded Flow, ft 3/sec 49,200 46,780 (4-12-52) (4-15-65) 1. Data from Hydrologic Atlas of Minnesota, Bulletin #10, Minnesota Department of Conservation, April 1959, at U.S. Geological Survey, Recorder 2755. Station discontinued October 31, 1957 (Reference 36).

2. Data from Northern States Power Company records from July 1, 1925, to December 31, 1965, at Whit- ney Steam Plant, St. Cloud, Minnesota (Reference 37).

Revision 22 USAR 2.5MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 1 of 5SECTION 2SITE AND ENVIRONS I/djm2.5Geology and Soil Investigation2.5.1General Dames and Moore, consultants in applied earth sciences, analyzed the geology and foundation conditions of the plant site.2.5.2Regional Geology Rocks dating as early as Precambrian time underlie the region of Minnesota which includes the plant site. Pleistocene glaciation, probably less than 1,000,000 years in age, as well as recent alluvial deposition have mantled the

older rocks with a variety of unconsolidated materials in the form of glacial

moraines, glacial outwash plains, glacial till, and river bed sediments. This cover of young soil rests upon a surface of glacially-carved bedrock consisting of sandstone and shale strata underlain by deeply weathered granite rocks.

Volcanics also form portions of the bedrock sequence in certain areas. The

bedrock surface is irregular and slopes generally to the east or southeast.

The geologic column showing the age relationships of the various bedrock unitsand surficial deposits of the region is presented in Table 2.5-1. Figure 2.5-1aand 2.5-1b show the regional extent of the consolidated formations.

The principal structural feature in this part of Minnesota is a deep trough formed during Precambrian time in the granite and associated crystalline rocks. This

basin extended from Lake Superior into Iowa, and provided a site for the deposition of thick sequences of Precambrian and later Paleozic sediments and volcanics. Strata of Paleozoic age are now exposed along the southern half of

the structural trough. In the Minneapolis-St. Paul area, they form a circular basin containing artesian groundwater.

The ice fronts or glacial lobes advanced across this region during the last stage of glaciation, named the Wisconsin Stage. One lobe came from the general area

of Lake Superior and deposited terminal moraines immediately south of the present course of the Mississippi River. A later ice front advanced across the

area from the southwest, overriding the earlier moraines. Erosion of these glacial sediments by the Mississippi River has been active since the final retreat of the ice.

The present course of the Mississippi has no relation to the streams that flowed through the area prior to glaciation. There are therefore, old river channels which cross the region and which may be substantially deeper than the present river channel.FOR ADMINISTRATIVE USE ONLYResp Supv:CNSTP Assoc Ref:

SR:2yrs N Freq: USAR-MANARMS:USAR-02.05Doc Type:Admin Initials:Date:

9703 Revision 22 USAR 2.5MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 2 of 5 I/djmA major fault system of Precambrian age has been inferred from regional geophysical surveys. This fault system is associated with the Precambrian structural trough. The major movements along this fault system, which amount to thousands of feet, appear to have been restricted to Precambrian time. Minor

fault displacements occurred during the Paleozoic era, but faulting within the last

few million years is not in evidence.2.5.3Site GeologyThe site occupies a bluff which forms the southwest bank of the Mississippi River. Several flat alluvial terraces comprise the main topographical features on the property. These terraces lie at average elevations of 930 and 918 ft msl and in general, slope very slightly away from the river.

The present surface drainage of the immediate plant site area is mainly to thesouthwest, away from the river. Surface run-off will tend to collect in the

depression at the south end of the terrace where it is bounded by higher ground, then flow easterly to the river.

At the time of start of construction, most of the site was under cultivation, which has since been discontinued, with the remainder of the site area covered by

scattered low brush and small trees.

The pattern of the present meander system suggests that the channel to the south of the islands in the river is now the main channel. It is possible that the channel to the north of the islands may eventually be abandoned. If this occurs

during the lifetime of the plant it probably will result in increased erosion along the bluff at the plant site; however, this erosion is not a matter of concern because the actual amount would be small and not interfere with any structures.

The site is located on the extreme western edge of the Precambrian structuraltrough previously discussed under Regional Geology. A well in the town of

Monticello about 2-3/4 miles east of the site which was drilled to a depth of 500 ft did not encounter granite. Other well information generally indicates that 150 to 200 ft of unconsolidated alluvium and drift overlies sandstone and red shale of

unknown thickness at Monticello. All the rock and soil units present at the site

therefore slope eastward and thicken toward the sedimentary basin and its

artesian groundwater aquifers.

Decomposed granite and basic rocks of Precambrian age comprise the oldest formation at the site, within the depth investigated. This material lies below the ground surface at a depth of about 75 to 122 ft. (See Figures 2.5-1a through 2.5-5) Resting directly upon the weathered Precambrian crystalline rocks is approximately 10 to 15 ft of medium-grained quartz sandstone which, in general, is moderately well cemented. The upper surface of underlying rock can support

unit foundation loads up to 15,000 pounds per square foot.

Revision 22 USAR 2.5MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 3 of 5 I/djm Above the sandstone is a series of alluvial strata about 50 ft thick which consists predominately of clean sands with gravel, as well as a few layers of clay and glacial till. This alluvial sequence represents successive depositions of glacialoutwash, moraine, and more recently, sediments laid down by the Mississippi River. During its history this river has meandered as much as 1-1/2 miles south

of its present channel.

The distribution of the unconsolidated materials in the locality of the site is shownon Figure 2.5-1b.

The nearest known or inferred fault is the Douglas fault, located approximately23 miles southeast of the site as shown on Figure 2.5-1a. It is probable that the

site has not experienced any activity within recent geologic times.2.5.4Groundwater Large supplies of groundwater are available from the Mississippi River

sediments, the glacial deposits, and the underlying sandstones in the area. Most of the private wells in the area are shallow, and penetrate either the river

alluvium or the glacial deposits. The town of Monticello derives its water supply from a well approximately 237 ft deep which is believed to penetrate sandstone aquifers. The communities of Big Lake, Albertville, and Elk River also recover

water from this formation.

The general path of deep groundwater flow is to the southeast across the region surrounding the site for the plant. The regional gradient, therefore, broadly parallels the trend of the topography and the principal surface drainage.

Groundwater at shallower depths moves toward the Mississippi River or its

tributaries at variable gradients depending on local conditions.

The water table beneath the low terraces which border the Mississippi River usually lies at about river elevation and slopes very slightly toward the riverduring periods of normal stream flow. Such is the case at the site.

Movement of groundwater takes place within the three principal rock and soil materials at the site. In the decomposed, clayey granitic rocks, which are very

low in permeability relative to the overlying materials, the rate of ground water movement is extremely slow.2.5.5Foundation Investigation The location of the principal structures including the turbine and reactor

buildings, intake structure, stack and diesel building and soil borings are shown in Figures 2.5-1a through 2.5-5.

Dynamic soil tests were not considered because the probability of liquefaction isvery low under the cyclic loadings produced by the 1952 Taft earthquake (refer to Section 2.6.3), considering the density of the sand and overburden pressure.

Revision 22 USAR 2.5MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 4 of 5 I/djm Sands which are typically vulnerable to liquefaction are saturated, under low confining pressures, and have standard penetration test values of about N=5.

Laboratory studies by Seed and Lee (Liquefaction of Saturated Sands during Cyclic Loading, Journal Soil Mechanics and Foundation Division, ASCE, November 1966, Volume 92, No. SM6) (Reference 38) demonstrate that sands

denser than the critical void ratio can be made to liquefy under cyclic loading.

Consequently liquefaction has an extremely low statistical possibility in a cemented sand with standard penetration test values of N=80 or more, and could only occur under a very large number (e.g., 10,000) of very high stress cycles. The number of stress cycles that could be expected due to the Taft

earthquake is estimated to be less than 1000 cycles.2.5.6Conclusions No unusual features of the site geology are evident. Underlying formations are

adequate for foundation for the plant structures.

The geology and soil conditions have been investigated and found stable.Consequently, no special plant design features pertaining to the site geology were necessary.

Revision 22 USAR 2.5MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 5 of 5 I/djmTable 2.5-1 Geologic Formations in the General Area of the Site Geologic Age Geologic Name Description Remarks ERA PeriodCenozoicQuaternaryRecent DepositsUnconsolidated clay,Largely Mississippi silt, sand, andRiver deposits gravel PleistoceneUnconsolidated clay,Largely from Superiorsilt, sand, gravel,and Grantsburg lobesand boulders depos-of Wisconsin glaciation ited as till, outwash, lake deposits, & loessPaleozoicCambrianFranconia FormationSandstone and shale,May not be present in(St. Croix Series)some aquifer zonesimmediate area of site Dresbach Formation Sandstone, siltstoneMay not be present in (St. Croix Series)and shale, aquiferimmediate area of site zonePrecambrianKeweenawanHinckley Formation Sandstone Thin in the immediate area of the site. An important aquifer wheresufficiently thickRed Clastic SeriesSandstone and redProbably not present shale in immediate area of siteVolcanics Mafic lava flows withProbably not presentthin layers of tuffin immediate area of

and breccia site Granite and Assoc-Present at site iated Intrusives Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 1 of 6SECTION 2SITE AND ENVIRONS I/djm2.6Seismology2.6.1General John A. Blume, Associates, analyzed the seismology of the plant site. A copy of the Blume report is included in Appendix A.2.6.2Seismic HistoryIn Table 2.6-1 are listed numerically the earthquakes in the general region in and

around Minnesota. Those more applicable to the site are plotted on Figure 2.6-1. The earliest earthquake on record occurred in 1860 in central Minnesota;

thus over 100 years of records exist. During that period, earthquakes have hadlittle effect at the site. Since compilation of Table 2.6-1, there has been no observed evidence of seismic activity in the plant area.2.6.3Faulting in Area The nearest known or inferred fault - the Douglas Fault - is 23 miles southeast of the site (Figure 2.5-1a). According to referenced geological information, there is no indication that faulting has affected the area of the site in the last few million

years. The major fault system of Precambrian age, which is associated with the Precambrian structural trough, is seen on Figure 2.6-2. Major movements of thousands of feet along this system appear to have been restricted to Precambrian time, with minor displacements having occurred during the

Paleozoic era. Faulting within recent geologic time is not in evidence.Richters Seismic Regionalization Map (Figure 2.6-3) shows the area of the site in a probable maximum intensity of VIII, Modified Mercalli.This intensity has been based on the areas relationship to the Canadian shield.

Stable shields in other continents are usually fringed by belts of moderate seismicity, with occasionally large earthquakes. Historically, this area is too young to prove or disprove such seismic activity. The Modified Mercalli scale isexplained in Table 2.6-2.The Coast and Geodetic Surveys Seismic Probability Map of the United States(Figure 2.6-4) assigns the area to Zone 0 - no damage.FOR ADMINISTRATIVE USE ONLYResp Supv:CNSTP Assoc Ref:

SR:2yrs N Freq: USAR-MANARMS:USAR-02.06Doc Type:Admin Initials:Date:

9703 Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 2 of 6 I/djm It is considered that neither the regionalization nor the probability map is satisfactory in determining a proper seismic factor if considered alone. Each,however, is based on judgment and fact which, when weighed with other data, become more meaningful. In the case at hand, the assignment of an VIII as the

largest probable intensity for the general area must be tempered by the fact that

the intensity at or near the underlying sandstone will be much less than that

experienced in areas of less competent material, where invariably the maximum damage is sustained.

Earthquakes can and do occur in this region away from faults, and probably result from residual stresses due to recent glaciers. A quake similar to No. 12 and 24 in Table 2.6-1 was postulated near the site and using the dynamic response data obtained insitu, the Taft earthquake of July 21, 1952, North 69 West component with an applied factor of 0.33 was selected as bestrepresentative for the design earthquake. Figure 2.6-5 shows single-mass spectra when averaged.2.6.4Design CriteriaDesign criteria which utilize this earthquake record are discussed in Section 12.

Section 12 also gives specific design information related to the seismic analysis

of the building and equipment.2.6.5Seismic Monitoring System The Seismic Monitoring System annunciates the occurrence and records the

severity of significant seismic events.

The system is composed of three subsystems: the relatively simple annunciators and peak-recording accelerometers, and the more sophisticated acceleration sensors located in the drywell, on the refueling floor and in the seismic shed (located to the north of the warehouse).

Each of the peak-recording accelerometers is a self-contained unit. The sensing mechanism is a permanent magnet stylus attached to the end of a torsional accelerometer. Low frequency accelerations cause the magnet to erase

pre-recorded lines on a small (approximately 1/4 inch square) piece of magnetic tape. Because an erasure is permanent, only the peak acceleration that the tape has been subjected to can be deduced when the tape is developed. Each

peak recording accelerometer unit contains three torsional accelerometers and

magnetic tapes - one each for longitudinal, transverse, and vertical

accelerations.

The magnetic tapes can be removed from the accelerometers, developed, and evaluated by plant personnel for a rapid determination of the severity of a

seismic disturbance.

Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 3 of 6 I/djmThe accelerograph recording system gives a more detailed record of a disturbance than the peak recording accelerometers - it records accelerations in three directions (longitudinal, transverse, and vertical, as above) at each of the three sensor locations on magnetic tape cartridges. This system has five major components: trigger, three sensors, and the recording and control equipment.

When the trigger (located in the No. 12 125 Vdc battery room) senses the

beginning of a seismic disturbance, (an acceleration >

.01 g), it initiates thesystem power-on sequence and causes the EARTHQUAKE alarm to annunciate

in the control room. The recorder then converts the nine analog acceleration

signals (three sensors with three directions/sensor) into frequency modulated

tones and records them on the magnetic tapes (one for each triaxial sensor).

The recorder will run for 10 seconds after each trigger signal, up to a maximum of 30 minutes. The resulting tape gives a detailed record of the disturbance, butmust be sent off-site to be fully processed.The control room EARTHQUAKE annunciator is also initiated by any seismic switch of the Seismic Annunciator System. In addition to this, there are two

more alarms initiated by the Seismic Annunciator System. The first of these is the Operational Basis Earthquake (OBE) alarm which annunciates when its seismic switch senses an acceleration >

.03g. The second is the Design Basis Earthquake (DBE) alarm, which annunciates when its switch senses an

acceleration >

.06g. These two switches do not activate the accelerograph recording system.

Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 4 of 6 I/djmTable 2.6-1 Seismic History of the Region (Page 1 of 2) Location NWIntensity No.Date Place Lat.Long.(M.M.)Remarks

11860Central Minn. - -UnknownFelt over 3,000 square miles 210/9/1872Sioux City, Iowa42.797.0V Felt over 140,000 square miles 311/15/1877East Nebraska41.097.0VII Felt over 140,000 square miles. 47/28/1902East Nebraska42.597.5V Felt over 35,000 square miles. 57/26/1905Calumet, Mich.47.388.4VII Felt over 16,000 square miles. 65/9/1906Washabaugh County, S. D.43.0101.0VI Felt over 8,000 square miles. 75/26/1906Keweenaw Peninsula, Michigan47.388.4VIII Felt over 1,000 square miles. 85/15/1909Canada, felt to South50.0105.00VIII Felt over 500,000 square miles. 95/26/1909Dixon, Illinois42.589.0VII Felt over 40,000 square miles. 1010/22/1909Sterling, Illinois41.689.8IV-V 116/2/1911South Dakota44.298.2V Felt over 40,000 square miles. 129/3/1917Minnesota46.394.5VI Felt over 10,000 square miles.*132/28/1925Canada48.270.8VIII Felt over 2,000,000 square miles. 1410/6/1929Yankton, S. Dakota42.897.4V (est.) 151/17/1931White Lake, S. Dakota43.898.7V (est.)*1611/12/1934Rock Island & Moline, Illinois Davenport, Iowa41.490.5V 173/1/1935Eastern Nebraska40.396.2VI Felt over 50,000 square miles.*1811/1/1935Canada46.879.1IX and overFelt over 1,000,000 square miles, felt in Minnesota. 1911/1/1935Egan, S. Dakota44.096.6V (est.) 2010/1/1938Sioux Falls, S. Dakota43.596.6VFelt over 3,000 square miles.*Indicates epicenter not plotted on map.

Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 5 of 6 I/djmTable 2.6-1 Seismic History of the Region (Page 2 of 2) Location NWIntensity No.Date Place Lat.Long.(M.M.)Remarks 211/28/1939Detroit Lake, Minn.46.995.5V (est.) 226/10/1939Fairfax, S. Dakota43.198.8VI (est.) 237/23/1946Wessington, S. Dakota44.598.7VI (est.) 245/6/1947Milwaukee Area42.987.9VII Felt Sheboygan to Kenosha, Wis. 252/15/1950Alexandria, Minn.45.794.8V-VI (est.) 261/6/1955Hancock, Michigan47.388.4V 2712/3/1957Mitchell, S. Dakota43.898.0V 281/12/1959Doland, S. Dakota44.998.0V 2912/31/1961W. Pierre, S. Dakota44.4100.5VI Revision 22 USAR 2.6MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 6 of 6 I/djmTable 2.6-2 Modified Mercalli Intensity Scale of 1931 (Abridged)I.Not felt except by a very few under especially favorable circumstancesII.Felt only by a few persons at rest, especially on upper floors of buildings.

Delicately suspended objects may swing.III.Felt quite noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing motor cars mayrock slightly. Vibration like passing of truck. Duration estimated.IV.During the day felt indoors by many, outdoors by few. At night some awakened. Dishes, windows, doors disturbed, walls make creaking sound.

Sensation like heavy truck striking building. Standing motor cars rocked noticeably.V.Felt by nearly everyone, many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned.

Disturbance of trees, poles, and other tall objects sometimes noticed.

Pendulum clocks may stop.VI.Felt by all, many frightened and run outdoors. Some heavy furniture moved; a few instances of fallen plaster or damaged chimneys. Damage slight.VII.Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving motor cars.VIII.Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse; great in poorly built structures.

Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. Sand and mudejected in small amounts. Changes in well water. Disturbs persons driving motor cars.IX.Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb; great in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously.

Underground pipes broken.X.Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; ground badly cracked. Rails bent.

Landslides considerable from river banks and steep slopes. Shifted sand and mud. Water splashed (slopped) over banks.XI.Few, if any (masonry), structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipe lines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly.XII.Damage total. Waves seen on ground surfaces. Lines of sight and leveldistorted. Objects thrown upward into the air.

Revision 26 USAR 2.7MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 1 of 2SECTION 2SITE AND ENVIRONS I/kab2.7Radiation Environmental Monitoring Program (REMP)2.7.1Program Design and Data Interpretation The purpose of the Radiation Environmental Monitoring Program (REMP) at the Monticello Nuclear Generating Plant is to assess the impact of the plant on its environment (References 7 and 42). For this purpose, samples are collected from the air, terrestrial, and aquatic environments and analyzed for radioactive

content. In addition, ambient gamma radiation levels are monitored by thermoluminescent dosimeters (TLDs).

Sources of environmental radiation include the following:a.natural background radiation arising from cosmic rays and primordial radionuclides;b.fallout from atmospheric nuclear detonations;c.releases from nuclear power plants.In interpreting the data, effects due to the Plant must be distinguished from thosedue to other sources. To accomplish this, the program uses the control-indicator

concept suggested by NRC Guidelines.2.7.2Program Description The sample types and locations included in the current Radiation Environmental Monitoring Program (REMP) at the Monticello Nuclear Generating Plant arelisted in the Offsite Dose Calculation Manual (ODCM, Reference 8).

Sample locations are chosen to provide measurements of radiation and of radioactive materials in those exposure pathways and for those radionuclideswhich lead to the highest potential radiation exposures off site. The technique for establishing sample locations conforms to guidance provided by the NRC.

The air environment is monitored by continuous air samplers which filter out airborne radioactive particulates and adsorb airborne radioiodine.

Ambient gamma radiation is monitored at thermoluminescent dosimeter (TLD) stations located in a circular array around the plant. TLD stations are alsolocated around the site's Independent Spent Fuel Storage Installation (ISFSI).

The terrestrial environment is monitored through samples of groundwater and locally produced food products.01123676 Revision 26 USAR 2.7MONTICELLO UPDATED SAFETY ANALYSIS REPORT Page 2 of 2 I/kabThe aquatic environment is monitored through sampling sediment and water from the Mississippi River at locations upstream and downstream of the plant.Drinking water from the city of Minneapolis, which is drawn from the river, is also sampled.2.7.3Interlaboratory Comparison Program Monticello participates in an Interlaboratory Comparison Program to ensure the

precision and accuracy of radioactivity measurements of environmental samples.

This program is described in the ODCM.

MONTICELLO UPDATED SAFETY ANALYSIS REPORT USAR-0 2.0 8 SECTION 2 SITE AND ENVIRONS Revision 23 Page 1 of 1 2.8 Ecological and Biological Studies On August 26, 1977 the Minnesota Pollution Control Agency, the permitting agency under the U. S. Environmental Protection Agency, issued the National Pollution Discharge Elimination System (NPDES) Permit No. MN0000868 covering the Monticello Nuclear Generating Plant. This permit is reissued with any modifications required every 5 years. The NPDES effluent limitations and monitoring requirements, thermal studies and ecological monitoring requirements provide appropriate protection for the environment.

There are no ecological or biological monitoring requirements under NRC jurisdiction.

Pre-operational and early operational ecological and biological studies are described in the FSAR. An environmental assessment (EA) of MNGP operation at Extended Power Uprate (EPU) conditions was submitted to the NRC (Reference 45, Enclosure 4). The assessment was subsequently updated by Reference 47. Approval of the updated EA was completed in May 2013 (Reference 46). The assessment evaluated the continued applicability of ecological and biological studies for EPU operation.

01101248 SECTION 22.92.9.1

SECTION 22.10