ML24159A235

Updated Final Safety Analysis Report (Ufsar), Revision 32, Chapter 2, Site and Environment

ML24159A235
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Site:	Cook
Issue date:	05/30/2024
From:	Indiana Michigan Power Co
To:	Office of Nuclear Reactor Regulation
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2.0 SITE AND ENVIRONMENT.................................................. 1 2.1 SITE DESCRIPTION.....................................................................1 2.1.1 Summary................................................................................... 1 2.1.2 Location.................................................................................... 1 2.1.3 Topography............................................................................... 2 2.1.4 Access....................................................................................... 3 2.1.5 Population................................................................................. 4 2.1.6 Land Use................................................................................... 8 2.2 METEOROLOGY.........................................................................9 2.2.1 Sources Of Data..................................................................... 10 Old Site Meteorological Tower............................................................................ 10 Old Satellite Aerovane....................................................................................... 11 Meteorological System Description.................................................................... 12 Temperature Sensor Specifications.................................................................... 12 Precipitation Monitor Specification Sensor Specifications.................................. 13 Special Studies.................................................................................................. 14 Analysis.................................................................................................. 14 2.2.2 General Meteorology.............................................................. 14 High Winds.................................................................................................. 15 Ice Storms.................................................................................................. 15 2.2.3 Dispersion Meteorology......................................................... 15 2.2.3.1 Turbulence Classification.............................................................. 16 2.2.3.2 Representativeness of Wind Speeds............................................ 17 2.2.3.3 Onshore Winds During Stable Conditions..................................... 17 2.2.3.4 Atmospheric Dispersion Models.................................................... 18 2.2.3.5 Normal Operation.......................................................................... 19 2.2.4 References for Section 2.2..................................................... 19 INDIANA MICHIGAN POWER Revised 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: iiof v

2.3 GEOLOGY............................................................................... 20 2.3.1 Regional Geology................................................................... 20 Physiography.................................................................................................. 20 Stratigraphy.................................................................................................. 20 Structure.................................................................................................. 20 History.................................................................................................. 21 2.3.2 Site Geology........................................................................... 21 Physiography.................................................................................................. 21 Surficial Geology................................................................................................ 22 Subsurface Geology........................................................................................... 22 2.3.3 Summary of Conclusions...................................................... 23 2.4 HYDROLOGY........................................................................... 24 2.4.1 Surface Water Hydrology....................................................... 24 Regional.................................................................................................. 24 Local.................................................................................................. 24 2.4.2 Ground-Water Hydrology....................................................... 24 Regional.................................................................................................. 24 Local.................................................................................................. 25 2.4.3 Summary of Conclusions...................................................... 26 2.5 ENGINEERING SEISMOLOGY..................................................... 28 2.5.1 Seismicity............................................................................... 28 2.5.2 A Seismic Design................................................................... 29 Foundation Materials.......................................................................................... 29 Operating Basis Earthquake............................................................................... 29 Design Basis Earthquake................................................................................... 30 Response Spectra.............................................................................................. 30 Supplemental Data............................................................................................. 32 INDIANA MICHIGAN POWER Revised 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: iiiof v

2.5.3 Conclusions............................................................................ 32 2.6 LIMNOLOGY AND ECOLOGY...................................................... 34 2.6.1 Limnology and Ecology Introduction................................... 34 2.6.2 Initial Studies.......................................................................... 35 2.6.2.1 Study Groupings............................................................................ 35 Physical Limnology............................................................................................. 35 Biological Studies............................................................................................... 35 Sediment Chemistry........................................................................................... 35 Water Chemistry................................................................................................. 35 2.6.2.2 Purpose of Initial Phase Studies................................................... 36 Physical Limnology............................................................................................. 36 Biological Studies............................................................................................... 36 Sediment Chemistry........................................................................................... 36 Water Chemistry................................................................................................. 36 2.6.2.3 Initial Study Results....................................................................... 37 Physical Limnology............................................................................................. 37 Biological Studies............................................................................................... 40 Sediment Chemistry........................................................................................... 41 Water Chemistry................................................................................................. 41 2.6.3 NRC Technical Specification, Appendix B Phase Studies (1973-1982).............................................................................. 41 2.6.3.1 Study Groupings............................................................................ 42 Physical Limnology Studies................................................................................ 42 Biological Studies............................................................................................... 42 Sediment Chemistry Studies.............................................................................. 42 Water Chemistry Studies.................................................................................... 42 2.6.3.2 Purpose of Technical Specification, Appendix B Studies.............. 42 Physical Limnological Studies............................................................................ 43 INDIANA MICHIGAN POWER Revised 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: iv of v

Biological Studies............................................................................................... 44 Sediment Chemistry Studies.............................................................................. 44 Water Chemistry Studies.................................................................................... 45 2.6.3.3 Results of Technical Specification, Appendix B Studies............... 45 Physical Limnology Studies................................................................................ 45 Biological Studies............................................................................................... 50 Sediment Chemistry Studies.............................................................................. 62 Water Chemistry Studies.................................................................................... 62 2.6.4 Ongoing Study Phase (1983 to Present)............................... 63 2.6.5 References for Section 2.6..................................................... 64 2.7 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM......... 65 2.7.1 Purpose of the Radiological Environmental Monitoring Program (REMP)..................................................................... 65 2.7.2 Preoperational Study............................................................. 65 2.7.3 Summary of Preoperational Radiological Environmental Monitoring Program............................................................... 65 2.8 PLANT DESIGN BASES DEPENDENT UPON SITE AND ENVIRONS CHARACTERISTICS................................................................... 67 2.8.1 Unit Vent Gas Effluent............................................................ 67 2.8.2 Liquid Waste Effluent............................................................. 67 2.8.3 Wind Loading Design............................................................. 67 2.8.4 Geology................................................................................... 67 2.8.5 Hydrology............................................................................... 67 2.8.6 Seismology............................................................................. 68 2.8.7 Limnology............................................................................... 68 2.9 PLANT DESIGN CRITERIA FOR STRUCTURES AND EQUIPMENT.... 69 2.9.1 Definition of Seismic Design Classification......................... 69 INDIANA MICHIGAN POWER Revised 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: v of v

Class I.................................................................................................. 69 Class II.................................................................................................. 69 Class III.................................................................................................. 69 2.9.2 Classification of Structures and Equipment......................... 69 2.9.3 Seismic Design Criteria for Seismic Class I and II Piping... 74 2.9.4 Seismic Design Criteria for Class I, Class II and Class III Structures............................................................................... 76 Class I.................................................................................................. 76 Class II.................................................................................................. 76 Class III.................................................................................................. 76 For All Structure Seismic Classifications............................................................ 76 2.9.5 General Design Considerations for Building Structures..... 78 Auxiliary Building................................................................................................ 79 Turbine Building.................................................................................................. 82 Emergency Diesel Generator Ventilation Structures.......................................... 82 2.9.6 Seismic Design Criteria for Equipment................................. 83 2.9.6.1 Use of Earthquake Experience Data as a Method for Assessing Equipment Seismic Adequacy...................................................... 84 2.9.6.2 References for Section 2.9.6......................................................... 84 Qualification of Masonry Block Walls.................................................................. 85 2.10 CONCLUSIONS......................................................................... 87

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2.0 SITE AND ENVIRONMENT

2.1 SITE DESCRIPTION 2.1.1 Summary The site is located in a region devoted primarily to agriculture. There are no continuously occupied residences within 2160 feet of the reactor containment structures. The distances from the reactor containment structures to the areas defined in the Rules and Regulations Title 10 Chapter I Part 100 are as follows:

Exclusion area 650 acres Minimum distance to exclusion area 2000 feet Outer boundary of low population zone 2 miles Population center distance 8 miles The closest population center is the twin cities of Benton Harbor-St. Joseph, Michigan. The site, therefore, provides excellent isolation as well as low population densities over a wide area.

2.1.2 Location The site is located in Lake Township, Berrien County, Michigan, about 11 miles south-southwest of the center of Benton Harbor, Michigan. The axis point of the Cook Nuclear Plant is latitude 41°58'32.07" and longitude 86°33'54.87." Figure 2.1-1 shows the regional features of the area up to 60 miles from the site, while Figure 2.1-2 indicates the features within about 15 miles of the facility.

The site consists of about 650 acres along the eastern shore of Lake Michigan, with approximately 4350 feet of Lake frontage, and extends an average of about one and one quarter miles eastward from the lake.

The entire site, with the exception of the right of way for Interstate Route 94, about 400 feet from the eastern site boundary, is controlled by the Indiana Michigan Power Company (I&M). No residence is permitted inside the site boundaries.

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Figure 2.1-3 shows a map of the plant site defining the plant property lines.

1. The boundary lines inside of which I&M exercises exclusive control of access are the property lines which are to the west of the Interstate 94. These property lines are also the boundary lines at which gaseous effluent limits apply. The line in the area of Lake Michigan is the shore line El 580'-0" extended by 100 feet toward the lake, up to which I&M exercises rights, besides those obtained to install, maintain and operate the condenser cooling water intake and discharge pipes.

Riparian rights extend to the low water line which in consideration of the lake bottom movement is approximately 100 feet outward from the elevation 580' line.

2. The points on the plant structure from which gaseous effluent containing, or potentially containing, radioactivity will be released; and the distance of each from the nearest boundary line have been shown and tabulated on the map (see Figure 2.5-1a.) Points 3, 4, 5 and 6 may release radioactivity effluents only during conditions of primary to secondary leakage.

3. There will be no residential housing on site. Only Plant personnel in the conduct of their duties are permitted along the beach in front of the plant.

There are no military installations, missile sites, or industrial facilities located beyond the Donald C. Cook Nuclear Plant Site boundaries at which an accident might cause interaction with the plant so as to affect public health and safety.

The plant is located along the lakeshore approximately midway between the northern and southern boundaries of the site. The distance from either of the reactor containment structures to the nearest site boundary is 2000 feet.

Figure 2.1-3 indicates the topographical details of the site and the location of the plant. Figure 2.1-4 is an aerial photograph of the site and its immediate environs before plant construction began.

2.1.3 Topography The site consists primarily of heavily wooded rugged sand dunes. A sandy beach slopes gently upwards for about 200 feet from the lake before rising sharply into the dunes. The peaks of the highest dunes reach an elevation of about 120 feet above the lake's surface; depressions between the dunes are as low as 10 feet above lake level.

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Figure 2.1-4a shows modifications in the site topography due to plant structures. Figure 2.1-4b shows views of the site from the minimum exclusion radius to major plant structures showing the topography of the site in relation to major plant structures.

2.1.4 Access The site area is accessible by air, rail, and road.

The Pere Marquette Line, runs in an approximately north-south direction about 1600 feet east of the site's eastern boundary. A corridor between the site and the railroad has been purchased to permit construction of a rail spur, and a bridge spanning Thorton Drive and Interstate Route 94 has been erected to provide direct rail access to the plant.

Interstate Route 94 runs through the eastern portion of the site in a north-south direction, while the Red Arrow Highway runs along the eastern boundary in the same general direction. Thorton Drive, a local roadway, runs parallel to Interstate 94 and slightly to the west of it, while Livingston Road, also a local thoroughfare, forms the southern site boundary.

Within the 15-mile vicinity of the Donald C. Cook Nuclear Plant there are two airports:

Southwest Michigan Regional Airport located approximately 12 miles NE of the plant on the NE edge of Benton Harbor and Andrews University Airport located approximately 10 miles East of the plant near Berrien Springs. For airports beyond this 15-mile radius, the orientation of runways and normal flight patterns are not in the direction of the plant or the normal glide path heights are not within the plant vicinity so that aircraft utilizing the facilities of these airports would not normally fly over the plant site.

Southwest Michigan Regional Airport has three runways all 100 feet wide, paved and lighted; Direction Length East-West 5100 feet North-South 3200 feet NW-SE 3750 feet For 1971 there were 67,690 operations (take -off or landings) resulting in 33,845 flights or an average of 93 flights per day of which only 9 were scheduled by commercial airplanes.

Weight load of aircraft using this field is limited to 30,000 pounds per single wheel load, which is the design specification for the concrete runways. Three classifications of airplanes utilize the airport facilities: corporate, private and commercial.

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Due to the North-Easterly location of the airport and the orientation of the runways, normal glide paths would not approach the vicinity of the plant. There are no specified glide path heights since erection of structures taller than 500 feet are not permitted within a 10 -mile radius of the airport. Neither is there a glide s lope. However, the East-West runway, which handles most of the traffic because of the prevailing winds, is the only runway having the localizer portion of the Instrument Landing System. This indicates only the aim of the airplane.

Andrews University Airport has two runways:

Direction Length Characteristics 310 o & 130 o 3100 feet Paved & Lighted 210 o & 30 o 2500 feet Sod & Unlighted

There are no records maintained concerning the number of flights. The airport manager has estimated that there are approximately 70 flights some days and none during inclement weather conditions for a yearly total of 4,000 to 6,000.

The maximum weight lo ad allowed is 12,500 pounds. There are no commercial flights; only corporate and private aircraft operate from this field.

There is no height, length, or orientation specified for a normal glide path.

2.1.5 Population The population data quoted in this section are a mixture of original analysis data, data obtained during an evacuation time estimate study performed during 1991-1992, and the demographic analysis performed during 1993. The evacuation time estimate study also provided updated information regarding schools and businesses near the Cook Nuclear Plant site. The demographic analysis projected future population in the Cook Nuclear Plant for the years 2000 and 2037.

Some of the population projections for individual sectors near the plant are greater than were anticipated in the original analysis. However, the referenced evacuation time estimate study shows that the population living near the plant could leave the area in a reasonable amount of time in the unlikely event of an ordered evacuation. Therefore, the combination of these time estimates and the fact that the total 10 mile emergency planning zone (EPZ) population has not exceeded projections indicate that there is no adverse impact on the EPZ population.

The area within 60 miles of the site, which encompasses portions of Southwestern Michigan, Northwestern Indiana, and Northeastern Illinois, is a region of moderate population that INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 5 of 87

contained approximately 4,073,369 people in 1990. The population of this area from 1975 to 1990 has declined 12%. This decline in total population is attributed to the steady decline of the Chicago area. It is projected from the year 1990 to 2000, the population will increase approximately 3.3%. From 2000 to 2037, it is expected the population will increase by another 3.9%. The projected population distribution information for the years 1990, 2000, and 2037 is located in Tables 2.1-6 and 2.1-6a, 2.1-7 and 2.1-7a, and 2.1-8 and 2.1-8a, respectively.

The closest population center is the twin cities of Benton Harbor-St. Joseph with a combined 1990 population of 22,032. The closest population center boundary is the southern edge of St.

Joseph, about eight miles north-northeast of the plant. All population centers within 60 miles of the site are indicated in Table 2.1-3.

The closest continuously occupied residence to the plant lies about 2160 feet to the north.

Figures 2.1-6, - 6a, and -6b shows the 1990 population distribution around the site up to a distance of 60 miles. The Low Population Zone is identified in Figure 2.1-6 as the zone included within the 2-mile radius. Figure 2.1-6 divides the region from 0 to 5 miles from the plant into concentric circles and sectors of 221/2°, where as Figure 2.1-6a and - 6b divides the region from 5 to 60 miles and 10 to 60 miles, respectively. Similar data for the years 2000 and 2037 are included in Figures 2.1-7, -7a, - 7b and 2.1-8, - 8a, -8b. Population data are presented in tabular form in Tables 2.1-1 through 2.1-8b.

Thirty-four public and parochial schools exist within a ten -mile radius with 625 teachers and a student population of 11,621. (1992)

Data collection to provide forecasts for the 21 counties entirely or partially within the 60- mile radius of the Donald C. Cook Nuclear Plant site was performed. This data was processed with the U.S. Census TIGER digital maps to apportion population forecasts for the years 2000 and 2037 for the radial distances and sectors as presented in the tables and figures. This analysis included the assignment of population forecasts for cities and towns within Berrien County, Michigan by one mile increments for the 0 to 5 mile area, and a five mile increment for the 5 to 10 mile area for forecast years 2000 and 2037. Similar forecasts were developed for the 10 to 60 mile area by ten mile increments for the sixteen 22 1/2°compass sectors.

The "best available data" regarding population growth during this study was obtained from the following sources:

For the State of Michigan, initial population forecast data was obtained through telephone conversations with the State Demographer, State of Michigan, INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 6 of 87

Department of State Planning and Commerce. (It should be noted that the existing State forecasts are based on pre -1990 census data and are subject to change when new projections are released.) Based on highly variable trends in population growth over the past few decades, it was suggested that it is difficult to determine what the long-range growth to the year 2037 will be. Thus, for the purposes of this analysis, population forecasts for the years 2000 and 2037 were derived using adjusted growth factors based on 1990 census data. More detailed local data for cities and towns in Berrien County was obtained through numerous informal communications with the Southwestern Michigan Commission.

For the State of Indiana, county population forecasts were obtained through telephone conversations and from subsequent data provided by the State of Indiana reporting the results of the Business Research Center estimates for population growth through 2030.

For Cook County Illinois, population forecasts were obtained through telephone conversations with the Northeast Illinois Planning Commission, which cited pre-1990 forecasts from the Illinois Bureau of the Budget, Illinois Population Trends -

1900.

In addition to the permanent resident population, Berrien County experiences an influx of approximately 3000 to 4000 summer residents each year. The great majority of the summer homes and cottages are located along the Lake Michigan Beach and in the Paw Paw Lake region in the north-eastern portion of the county.

The closest summer colony to the plant is the Rosemary Beach Association just north of the site boundary. Rosemary Beach is virtually uninhabited during the Fall, Winter and Spring and has a population of up to 150 during the peak of the summer season.

During the late summer and fall fruit harvest, substantial numbers of migrant farm workers are employed in Berrien County. The maximum number recorded in 1976 was 6,800.

Table 2.1-8b and Figure 2.1-10 represent the seasonal transient population out to the Population Center Distance of 8 miles with the 0 -2 mile population figures representing the Low Population Zone.

The Work Employment Security Commission supplied data for total migrant workers in Berrien County in 1971 working as transient crop pickers. This total, consisting of 8355 workers, was uniformly averaged over the entire county rural area resulting in an average total of 1263 INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 7 of 87

migrants within the Population Center Distance distributed evenly over the rural area. Some migrant workers arrive in the Spring to cut asparagus but most of them begin to arrive in the latter part of August, building up to a peak in the Fall during the peach and apple crop-picking periods. After the crops have been harvested, they leave the area.

The number of summer homes were supplied by the Twin Cities Chamber of Commerce (St.

Joseph - Benton Harbor) and the Berrien County Clerks Office, and the number of people occupying the various beach areas were estimated from visual observations in 1971. Most of the summer vacationists begin to arrive in June when school ends and leave in late August when school recommences; although, a few remain into the Fall as long as favorable weather conditions exist. These vacationists are located mostly along the lakeshore front.

Although, there is an overlapping of the seasonal transient population towards the end of summer; in general, there are two reasons: the summer months consisting of vacationists and the fall months consisting of migrant crop pickers.

The trend is towards a decreasing number of transients within Berrien County and hence within the Population Center Distance.

The migrant workers in the county decreased from a total of 11,100 in 1966 to 8,355 in 1971.

This decline is attributed mainly to automation in the crop -picking industry and to a reduced apple market since the cost of picking will not support the apple market price.

Warren Dunes State Park lies along the lake about six miles south of the site. On a peak summer day in 1992, an attendance of 20,881 was recorded at the park of which 1,600 were overnight campers. In 1969, the park was enlarged somewhat to accommodate more daily visitors with increased camping facilities.

While the Warren Dunes State Park has changed from a 1976 summer peak of 23,958 days visitors of which 1300 were overnight campers to a 1992 day peak of 20,881 visitors of which 1600 were overnight campers, there has been a decline in the number of people occupying summer homes over the years with a decrease from 4,000 in 1964 to 3,000 in 1971 due to the high cost of home maintenance. Hence, the potential for a significant increase in transient population over the life of the plant does not seem probable especially within the Low Population Zone which comprises about 3 miles of lake shore front already containing four beach areas.

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2.1.6 Land Use The area surrounding the site is devoted primarily to agricultural pursuits. Over 60% of the land in the three counties, Berrien, Cass, and Van Buren, surrounding the site is devoted to farming.

The major crops produced are apples, cherries, grapes, peaches, feed grains, livestock and dairy products. Agricultural statistics are summarized in Table 2.1 -9.

Figure 2.1-9 illustrates the number of farms with dairy cattle, the number of dairy cattle per farm, and their distance from the plant within a 10-mile radius (as of 1972).

In 1990, the low population zone contained approximately 764 permanent residents with no more than 174 in any 221/2° sector. Industrial activities in the area are centered around Benton Harbor and Niles, Michigan. The primary industries are home appliances, metal casting and electronic and audio equipment. Updated information on Local Schools and Hospitals is given in Table 2.1-12.

Lake Michigan water in the vicinity of the plant site is not used for irrigation. Lake Michigan is however used for swimming, fishing, boating, domestic water supply and sewage. Only crab fishing in water over 30 fathoms is permitted commercially in Michigan waters. The Rickman -

Jameson 1971 Sport Fishing Survey for Berrien County (Lake Michigan) indicates the following species and number caught:

Perch 748,800 Walleye 640 Northern Pike 2,120 Lake Trout 6,960 Rainbow & Steelhead Trout 15,120 Brown Trout 3,160 Coho 94,680 Chinook 3,540 In 1971, 24,200 anglers fished 203,260 angler days. There are 4,850 registered boats within a 50-mile radius of the plant site. About 31/2 million people use the lake annually within the 50-mile radius.

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2.2 METEOROLOGY

Due to the extreme importance of site meteorology, particularly with regard to safety considerations, an extensive meteorological study program was initiated at the site during the summer of 1966.

The meteorological features of the plant site were evaluated primarily on the basis of three years data obtained from the 200- foot tower which was installed on the site in 1966. Satellite aerovane stations at inland and on-site locations were used to complement the main tower data. Data from the original meteorological study can be found in the original FSAR. Recently, the meteorological features have been further evaluated on the basis of five consecutive years of data from 2001 to 2005. These data were obtained from the 60-meter primary tower and 10-meter shoreline tower.

According to the original meteorological study, in most respects, the meteorological patterns were those of a typical open mid-latitude exposure. The wind speeds were strong, variations in direction were frequent and the overall wind rose showed no marked favoritism for any particular direction. The only unusual feature was the low frequency of stable conditions. Both the lapse rate and turbulence class analyses indicate far fewer stable cases than originally anticipated, reaching only 7% over the three year period. Even in the late spring and early summer when the lake was relatively cold, the frequency of stable cases reached only 20 to 25%.

According to the recent data from 2001 to 2005, extremely stable conditions (i.e.,Pasquill class G) occurred 9.1% of the five year period, and moderately stable conditions (i.e.,Pasquill class F) occurred 7.9% of the five year period.

According to the original meteorological study, even more favorable was the very low frequency of the combination of light winds and stable, on-shore flow. Less than 1% of the 200- foot data and only 2.5% of the satellite data were in this category. According to the recent data from 2001 to 2005, less than 1% of the 60- meter data (0.4% during Pasquill class G and 0.2% during Pasquill class F) and only 2.2% of the shoreline data were in this category (1.0% during Pasquill class G and 1.2% during Pasquill class F).

The only major meteorological hazard expected in the site area is the tornado, which has recurrence frequency of over 5000 years at the site itself. Ice storms, which would be expected with greater frequency, are not likely to damage essential facilities, but have been considered in developing certain criteria.

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2.2.1 Sources Of Data Old Site Meteorological Tower The main source for the initial site meteorological data was a 200 -foot meteorological tower, which was erected at the site during the summer of 1966 and equipped with meteorological instrumentation (Fig. 2.2-1). This tower remained in continuous operation from October 1966 until 1978. The tower instruments consisted of the following:

200 ft. level Aerovane and aspirated resistance thermometer.

150 ft. level Climet Bivane (the extremely strong winds at the site had damaged the Bivane, but some data had been obtained).

50 ft. level Aerovane and aspirated resistance thermometer.

Ground-level Resistance thermometer, Dewcell, recording rain gage and recording barometer.

In the Unit 1 Control Room there was instrumentation and a recorder for wind speed, direction and temperature.

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Old Satellite Aerovane In addition to the measurements taken directly at the site, a third aerovane was located inland in the summer of 1966 on a short pole in the flat terrain about 2 miles east of the tower. This instrument was transferred to a pole on the site near the beach in the Spring of 1969 to measure unobstructed wind speed. It was replaced in December 1969 by a more sensitive RAIM wind instrument to obtain better response in the low-speed range. Construction progress made it necessary to make an adjustment to the location of the pole, and it was accordingly moved a short distance in July 1970 to a point where it still measured unobstructed wind speed. The detectors at these satellite locations were about 50 feet above the ground level. The elevations of the aerovane detectors are listed below.

Elevation USGS

200 feet level on main tower 892' 50 feet level on main tower 742' Inland satellite 701' Beach satellite (previous location) 696.3' Beach satellite (present location until 1978) 656' Plant grade 608' Average lake water level 580.4' The inland satellite and the beach satellite are also no longer in operation.

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Meteorological System Description The tower locations for the meteorological system are shown in Figure 2.2-23. The system includes primary, backup, and shoreline towers tied into a central computer via microprocessors.

Readouts of data are provided in both control rooms. Data is recorded at each tower site. Each tower measures wind speed and wind direction. The primary tower and the shoreline tower measure temperature. The primary tower also measures precipitation. The instruments are made by Climatronics Corporation. The specifications for the instruments are as follows:

F460 Wind Speed F460 Wind Direction Accuracy +/-/sph)+/- 1.0% of tei +/-2o speedwhis+/-eat)

Teshold +/-/s0.5 mph) /s0.5 mph) istonstt Vinyl:5 ft ofi+/-ataiess t ofi+/-ax Steel: 2.4m8.0 ft ofi+/-ax.

agatio 0.4 at 10o angf tack O+/-atiange 0-/s0 -125 mph) 0o to 360o

Temperature Sensor Specifications Accuracy +/-0.15oC (+/-0.27oF) over full range Range -30.0o to 50.0oC (-22.0o to 122.0oF)

Time Constant 3.6 s Interchangeability +/-0.15oC (+/-0.27oF)

Linearity +/-0.16oC (+/-0.29oF)

Leads 3 Size 0.64 cm dia x 11.4 cm long (1/4" x 4 1/2")

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Precipitation Monitor Specification Sensor Specifications 8" Tipping Bucket

Accuracy +/-1% up to 7.5 cm/hr (3 inch/hr)

+/-5% up to 25 cm/hr (10 inch/hr)

Resolution (Sensitivity) 0.025 cm (0.01 in)

The primary site is a 60-meter tower on plant property. The base of the tower is at approximately 650' above sea level. The tower and its instruments are located in an area relatively free of interfering structures and vegetation, and are within the thermal internal boundary layer (TIBL) during on-shore flow. By being within the TIBL, the tower measurements are representative of the meteorology in the emergency planning zone.

The primary tower has the following instrumentation:

1. Wind Direction at the 10m and 60m levels.

2. Wind Speed at the 10m and 60m levels.

3. Temperature at the 10m and 60m levels.

4. Precipitation at the 1m level.

The primary tower is not equipped with redundant instrumentation. A back-up tower is used to maintain the ability to monitor wind speed and wind direction when the primary tower is unavailable. The back-up tower site is a siren pole located across from the plant entrance on Red Arrow Highway. The back-up tower has the following instruments at 10 meters above the base of the pole:

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The shoreline tower monitors representative conditions of unmodified marine air. The shoreline instruments are located on a siren pole on the shoreline. The base of the tower is at approximately 600' above sea level. The shoreline tower has the following instruments:

Wind Direction at the 10m level.

Wind Speed at the 10m level.

Temperature at the 10m and 2m level.

Each site has a microprocessor to calculate 15 minute averages and this information is transmitted to a central computer.

The central computer to collect meteorological data is located on the plant property. It polls the meteorological tower site microprocessor for the 15 -minute averages for each instrument. The central computer has software to calculate 10 CFR 50, Appendix I dose estimates. The central computer provides meteorological data to the PPC system. Meteorological data from the PPC display is entered into a stand-alone PC running the accident dose assessment program. This program provides dose estimates for emergency planning.

Special Studies Phenomena having relatively long recurrence intervals, such as tornadoes and ice storms, in the area cannot be studied directly from site observations and estimates have been derived from special reports. (References 1, 2, 3, 4, and 6)

Analysis The initial meteorological data from the Donald C. Cook Nuclear Plant site were abstracted, processed and analyzed on a monthly basis by Maynard E. Smith, Inc., Meteorologists, Inc. The computer output from which the analysis is made is too extensive to include as a part of this report. The summaries given here are derived from it. Table 2.2-1 is a sample of the original (1969) hourly records in the computer data file. Table 2.2-2 is a sample of the meteorological tower system's data output (1992).

2.2.2 General Meteorology Southwestern Michigan is typical of the northern lake regions of the United States in most respects. The flat terrain and the frequent passage of well-developed extra-tropical storms create a consistently strong wind flow, as well as rapid changes in both dispersion conditions and wind direction. Some of the meteorological statistics are useful primarily for general planning of the INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 15 of 87

facilities and are therefore reported with a minimum of description. Other data are important in the assessment of safety and these are discussed fully.

High Winds Strong winds are the most important meteorological hazard to the facilities. The region is frequented by relatively strong, gusty winds, usually accompanying the passage of squall lines or thunderstorms and the maximum wind associated with these phenomena is 90 mph on a 100 year recurrency interval.

The tornado presents a very specialized type of hazard involving both violent winds and extremely large, rapid changes in barometric pressure.

The storms are small, unpredictable in detail and rather infrequent, but they undoubtedly represent one of the few environmental factors that could, if ignored in plant design, inflict direct major damage on the facility. Typically, the tornado is a narrow funnel, often only a few hundred yards wide, in which winds may briefly reach 300 mph. Almost instantaneous changes in barometric pressure occur, reaching 3 psi and causing explosion of vulnerable structures.

Because of the severity of the phenomena, very few reliable measurements of tornado intensities exist. It is therefore difficult to dissociate wind and pressure effects, but the estimates given above are considered fairly reliable maximum values. This portion of Michigan has a significant tornado probability, as is apparent in the map shown in Figure 2.2-2. Berrien County has had 25 tornadoes between 1950 and 1989.

Ice Storms Far less destructive, but far more probable, are the ice storms that frequent the north central states. Michigan lies in the belt where such stor ms are common and in the years from 1970 to 1989, 6 significant ice storms have been reported in this area.

2.2.3 Dispersion Meteorology According to the original meteorological study, the micrometeorology of the site seemed fairly typical of the northern lake regions. The sand dunes in the immediate vicinity caused some aberration of wind flow at low levels for short distances, but, in general, the wind was vigorous, turbulent and uncomplicated over the entire area. The thermal stability showed approximately the seasonal variation expected close to large lakes, exhibiting almost no stable cases during the winter months, contrasted with a slightly greater frequency in inversions in the late spring and summer when the air temperature was usually warmer than that of the lake surface. According to the original meteorological study, even in the least favorable month, however, the inversion INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 16 of 87

frequency was only 22%.According to the recent dat a from 2001 to 2005, the inversion frequency was 56% in the least favorable month. There were almost no instances in which stable lapse rates were accompanied by winds toward the heavily populated Chicago areas.

2.2.3.1 Turbulence Classification According to the original meteorological study, the four turbulence classes employed in the analysis follow closely the system developed and used extensively by Smith and Singer.

Turbulence class I was clearly related to unstable lapse rates. Turbulence class II was also primarily related to unstable lapse rates, but a significant portion of the cases were associated with stable lapse rates. Turbulence class III was related to lapse rates between classes II and IV.

Turbulence class IV was related to stable lapse rates.

In the distribution of the four Smith-and-Singer turbulence classes on an annual basis, individual monthly variations among the three years were small, and the overall summary was a good representation of the typical distribution. Turbulence class I represented a very small percentage (4%) of the total observational period. Turbulence class II dominated the distribution throughout the year, accounting for 81% of all hours. Turbulence class III included a small percentage (8%)

of the overall hours. The surprisingly small frequency of turbulence class IV conditions was apparently a genuine feature of the site, since its annual occurrence was only 7% of the total.

But this frequency was more significant because of the relatively poor dispersion conditions associated with this turbulence class. At all of the locations, the distributions were surprisingly uniform.

Currently, the seven Pasquill turbulence classes A, B, C, D, E, F and G are used and represent extremely unstable, moderately unstable, slightly unstable, neutral, slightly stable, moderately stable and extremely stable, respectively. Joint frequency distributions of wind speed and wind direction by atmospheric stability class are presented in Tables 2.2-3 through 2.2-9 for the shoreline tower for the year 2005. Pasquill turbulence class A represented 23% of all hours.

Pasquill turbulence class D occurred 33% of the time. The annual average occurrence of Pasquill turbulence classes F and G were 6% and 7%, respectively. (Smith-and-Singer turbulence class IV encompassed Pasquill turbulence classes F and G.)

According to the original meteorological study, there was considerable seasonal variability in wind roses, but nothing was exceptionally significant from the point of view of dispersion problems. The most marked tendency for stable conditions occurred in the summer when the general wind flow in the area became relatively light. There was a tendency for an increase in INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 17 of 87

the number of stable hours during the spring, when the lake water was cold compared to the air temperature, but it was not especially marked.

2.2.3.2 Representativeness of Wind Speeds After the original main tower installation and inland satellite were in operation for the first full year, it became evident that there was some tendency for restriction of the low -level wind speeds as exemplified by the 50-foot level on the main tower. In particular, it was noted that the mean winds at the 50- foot level were much lower than those at the inland satellite, which were actually closer to the ground surface. Table 2.2-10 shows the problem very clearly: the wind speeds at the 50- foot level on the main tower were significantly lower than those at the satellite in all but the stable conditions. Furthermore, the comparison of the 50-foot speeds with those obtained from the 200-foot instrument on the main tower indicated an unreasonably rapid increase of wind speed with height, whereas the comparison between the satellite and the 200-foot levels were more in accord with typical results.

This restriction apparently was associated with the vegetation nearby and with the rugged dune structure. Since the terrain was being altered locally for construction purposes, it was felt that a wind instrument located nearer the beach would be more representative, and the 50-foot aerovane on the inland satellite was moved in the Spring of 1969. The instrument was replaced by a RAIM Associates cup and vane in December 1969 to provide greater sensitivity and accuracy at low speeds.

The recent data from 2001 to 2005 were similarly compared, as shown in Table 2.2-10. Mean wind speeds at the 10- meter level of the primary tower were significantly lower than those at the shoreline tower for all conditions (Pasquill turbulence classes A through G). In addition, the comparison of the 10-meter and 60-meter speeds from the primary tower indicated an unreasonably rapid increase of wind speed with height, whereas the comparison between the 10-meter speed from the shoreline tower and the 60- meter speed from the primary tower were more in accord with typical results. Therefore, the 10- meter speed from the shoreline tower was more representative.

2.2.3.3 Onshore Winds During Stable Conditions An important factor in safety analyses is the frequency of onshore winds accompanied by stable atmospheric conditions, and the speed of such winds when such a condition occurs. The data from the original beach instrument were reviewed from this standpoint. The frequency of onshore winds associated with stable conditions were reviewed for the five months in which the INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 18 of 87

beach instrument operated satisfactorily. The data were further broken down according to wind speeds in the 0 to 3 mph class and those exceeding 3 mph. Onshore was defined as any wind ranging from 180 to 010 degrees on the westerly side of the compass rose. Except for the month of August 1969, in which stable conditions were common, the combination of onshore winds of low speeds in stable conditions was very unusual. Based on this data, an annual frequency of occurrence of less than 1% of the 200- foot data and only 2.5% of the satellite data were anticipated.

According to the recent data from 2001 to 2005, an annual frequency of occurrence of less than 1% of the 60-meter data (0.4% during Pasquill class G and 0.2% during Pasquill class F) and only 2.2% of the shoreline data were anticipated (1.0% during Pasquill class G and 1.2% during Pasquill class F).

2.2.3.4 Atmospheric Dispersion Models Utilization of meteorological data in the assessment of safety requires selection of appropriate mathematical models for emissions and building characteristics, and the computation of concentrations. For design basis accident calculations, to ensure that the health and safety of the public is protected, one establishes the least favorable conditions that might be reasonably expected to accompany a release over a given period. The least favorable conditions according to the original meteorological study were Smith -and-Singer turbulence class IV, which encompassed Pasquill turbulence classes F and G.

Currently, the offsite atmospheric dispersion factor model is based on Regulator Guide 1.145, and the control room atmospheric dispersion factor model is based on the ARCON96 computer code. According to the original meteorological study, Smith and Singer derived horizontal and vertical atmospheric dispersion coefficients for the four turbulence classes partially from the aerovane records of wind direction and partially from general considerations of mid-latitude dispersion. The contribution of the horizontal and vertical atmospheric dispersion coefficients for the stable turbulence class IV gave results very close to Pasquill turbulence class F within the first kilometer from the source.

The resulting off-site and control room atmospheric dispersion factors (/Q values) used in radiological consequence calculations for design basis accidents are presented in Tables 2.2-11 and 2.2-12, respectively.

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2.2.3.5 Normal Operation Meteorological data used to compute non-accident doses to a member of the public is maintained current within the Off-site Dose Calculation Manual (ODCM). Other data contained herein is historical information.

Atmospheric dispersion factors for normal operation are calculated from data from the primary towers 10 meter instruments using the MIDAS computer code. Joint frequency distributions of wind speed and wind direction from the primary tower are shown in Tables 2.2-13 through 2.2-20 for 1992 (historical data - sample of a typical year).

Wind speeds were moderate in 1992 (historical data - sample from a typical year). The predominant wind speed range is 4-7 mph category. The wind speed exceeded 14 mph less than 4% of the time. The wind direction at the main tower varied, with the largest frequencies occurring both from the North and from the South. This can be observed in the wind roses shown in Figures 2.2-3 through 2.2-7. There was a slight tendency for winds from the West (onshore flow) to occur. The second quarter of the year produced winds mostly from the North, while during the fourth quarter they were from the South.

The wind at the shoreline (measured by the shoreline tower) shows a large contrast. The winds are mostly from the South East. This directional preference can be seen in all four quarters for 1992, as shown on the wind roses in Figures 2.2-8 through 2.2-12.

2.2.4 References for Section 2.2

1. Fawbush, Miller and Starrett: "An Empirical Method of Forecasting Tornado Development," Bulletin, AMS, 32, 1951.

2. Spohn et. al.: "Tornado Climatology," Monthly Weather Review, Wash., D.C., 1962.

3. Thom: "Tornado Probabilities," Monthly Weather Review, Wash., D.C., 1963.

4. Thom: "Distributions of Extreme Winds in the United States," Journal, Struct. Div.

ASCE, April, 1960.

5. Singer and Smith: "Relation of Gustiness to Other Meteorological Variables," Journal of Met., 1953.

6. Michigan Emergency Management Division, "M ichigan Hazard Analysis," September 1992.

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2.3 GEOLOGY

The geology of the site and surrounding areas is basically simple. Although bedrock in the area is concealed beneath thick glacial deposits, variable data indicate that the bedrock beneath the site conforms to the regional structural and stratigraphic system. The overlying glacial deposits are typical of those found in the vicinity of Lake Michigan. No anomalous geologic condition is known or suspected. A complete report of site geology is included in Appendix A to the Preliminary Safety Analysis Report.

2.3.1 Regional Geology Physiography The southern peninsula of Michigan lies within the Central Lowland Physiographic Province.

The topography is typical of areas of regional glaciation. As a consequence of glaciation, land forms are of low to moderate relief and generally smoothly contoured. Bedrock exposures are rare. Reaches of the Lake Michigan shoreline are characterized by extensive sand dunes and ancient shoreline features of Glacial Lake Chicago. Regional drainage in southwest Michigan is toward Lake Michigan on the west.

Stratigraphy The regional bedrock geology is relatively simple. The southwest part of Michigan is located on the flank of a very large synclinal basin, the Michigan Basin. Bedrock consists of a mixed sequence of sedimentary strata including shale, limestone, sandstone and dolomite. The strata range in age from Cambrian to Pennsylvanian. This sequence is underlain by a basement complex of Precambrian igneous and metamorphic rocks.

Bedrock formations in the vicinity of the site include shale and sandstones of Devonian and Mississippian age. The Precambrian basement is estimated to occur at a depth of 3,500 feet. In southwest Michigan, the surficial glacial deposits exceed 350 feet in thickness in places and overlie a moderately irregular bedrock surface. Valleys in the bedrock surface represent pre-glacial stream channels modified to a certain extent by glacial erosion. In the site area, the bedrock surface slopes generally north or northwest.

Structure The Michigan Basin is a remarkably symmetrical dish -shaped structure bounded on the north by the Canadian Shield and on the west by the La Salle Anticline and Wisconsin Arch. On the south side, it is bounded by the Cincinnati-Kankakee-Findlay Arch System. A number of large INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 21 of 87

faults have been mapped in areas surrounding the Michigan Basin. All but one lie well beyond the borders of the state. The principal geologic structures in the region are shown in Figure 2.3-l, Regional Tectonic Map.

In southwest Michigan, the bedrock formations dip at low angles to the northeast. Subsurface data indicated the presence of deeply buried folds and possible faults at a number of locations.

These structures are related to ancient crustal movements. The relatively minor folds do not carry through to succeeding younger formations, and no recent faulting can be identified. No fault or other geologic structure is evident within 50 miles of the site. One named structure, the Howell Anticline, is located in southeast Michigan. Some indirect evidence exists of a possible concealed subsurface fault tending in a northwest direction from Hillsdale County to Allegan County. At its closest approach, this postulated structural trend is located approximately 50 miles northeast of Benton Harbor. Evidence for this possible fault includes a negative gravity anomaly, structure contour steepening, an earthquake epicenter, and the occurrence of oil fields along the trend.

History The Michigan Basin was a basin of deposition and subsidence throughout most of the Paleozoic Era. The strata decrease in thickness away from the center of the basin and much of southwest Michigan appears to have been a submarine platform or shelf. Absence of Mesozoic and Cenozoic Strata indicate that the area was above sea level during this long period of time. The glacial deposits which fill irregularities in the eroded bedrock surface reveal a complex history of repeated advances and retreats of the Pleistocene glaciers. The last glacier, which extended south into Illinois and Ohio completely covered the State of Michigan. In the site area, it eroded or buried all evidence of earlier glacial stages. A series of end moraines parallel to the shore of Lake Michigan define the lobate character of the ice front and represent halts in the retreat of the last glacier. Some shoreline features adjacent to Lake Michigan are related to different stages in the level of ancient Glacial Lake Chicago which fluctuated in response to alternate damming of outlets by glaciers and opening of outlets at different elevations as the ice melted.

2.3.2 Site Geology Physiography The site is located within a local physiographic area known as the Grand Marais Embayment.

This area extends l6 miles parallel to the lake and has an average width of one mile. On the Lake Michigan side, it is characterized by high sand dunes and shoreline features of several glacial INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 22 of 87

lake stages. The area is bounded on the east by a glacial moraine known as Covert Ridge. This ridge is a drainage divide. The westward draining catchment area is limited and there are only a few, very small, intermittent streams on the west side of the ridge. At the site, the sand dunes rise abruptly from the narrow beach and extend inland about 6,000 feet. The shoreline in this area is stable.

Surficial Geology The western part of the site is covered by large coalescing sand dunes more than 150 feet high.

The eastern portion of the site is characterized by scattered lower dunes with broad intervening basins, some of which contain shallow ponds. Old shoreline features such as beaches, bars and spits occur at different elevations and are related to former lake levels.

Subsurface Geology The details of the subsurface geology were investigated by means of 19 test borings and geophysical studies. The borings reveal a simple sequence of deposits consisting of a surface deposit of dune sand which overlies older beach sand which in turn is underlain by glacial lake clays, glacial till and shale bedrock. In the eastern half of the property, the beach sands are absent and the dunes rest directly on glacial lake deposits. The subsurface conditions are illustrated on Figure 2.3-2, Geologic Cross Section. The dune sand is generally loose at and near the surface and grades to moderately compact with depth. The underlying beach sands are generally compact and commonly range from about 25 to 35 feet in thickness in the west-central portion of the property.

The surface of the lake deposits slopes upward gradually from elevations of about 555 to 560 feet along the beach to about Elevation 590 feet in the southeast corner of the site. These deposits comprise an irregularly interbedded series of clayey sediments 80 to 90 feet in thickness. The upper portion tends to be organic and, in places, a very thin layer of peat is encountered. The lake sediments exhibit varying strength characteristics. Commonly, the uppermost zone is firm to very firm and grades with increasing depth to layers that are generally firm to moderately firm. The higher strength of the upper zone is probably due to desiccation.

Below about Elevation 500 feet, the deposit is very firm.

In the deepest boring, a stratum of compact glacial till about 22 feet in thickness was encountered immediately overlying the bedrock. This stratum probably extends throughout the site and fills in irregularities in the bedrock surface. The bedrock consists of thin bedded shale with thin interbeds of shally limestone. Seismic refraction surveys indicate that the bedrock beneath the site has a relatively smooth, gently sloping surface. It occurs at elevations ranging INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 23 of 87

from 420 feet to 460 feet above sea level along the beach. Inland, the bedrock surface lies at elevations ranging from 400 feet to 420 feet above sea level.

2.3.3 Summary of Conclusions Based on the geologic studies, the following conclusions have been reached:

The geology of the site and surrounding area is basically simple. A thick sequence of sand dunes, beach sands and glacial lake and till deposits conceals the underlying shale bedrock.

Shoreline erosion is not evident at the site.

The bedrock characteristics and geologic features at the site conform to the regional conditions.

No fault or other adverse geologic phenomenon is known or suspected in the vicinity of the site.

Adequate foundation support for major structures is available from the lake clays and deeper glacial soils.

The geologic conditions at and in the vicinity of the site are satisfactory for the construction and operation of the nuclear power facility.

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2.4 HYDROLOGY

The surface drainage characteristics of the area are controlled by the glacial and sand dune topography and the nature of the surficial soils. The groundwater characteristics of the area are governed by the nature and distribution of the glacial deposits. A complete report of site hydrology was included in Appendix A to the Preliminary Safety Analysis Report.

2.4.1 Surface Water Hydrology Regional The gently undulating glacial terrain controls the surface drainage pattern. Regional drainage is westward into Lake Michigan. The drainage system is for the most part, very irregular and poorly developed. Small lakes and local swampy areas are abundant. The site is located within the Grand Marais Embayment drainage basin which is separated from the St. Joseph River drainage basin to the east by a glacial moraine known as Covert Ridge. A regional water budget analysis of the St. Joseph River drainage basin (the closest basin for which data are available) indicates an annual average precipitation of 34 inches, 41 percent of which is runoff and 59 percent of which recharges ground-water reservoirs and/or is lost as evapotranspiration.

Precipitation is fairly uniformly distributed throughout the year.

Local Only a few minor intermittent streams occur west of Covert Ridge. Thornton Valley, situated between the dunes area and Covert Ridge, contains a small intermittent stream, which traverses the eastern portion of the site via a man -made drain. Run-off from the eastern portion of the site drains north via Thornton Valley into the Grand Marais Lakes. Run-off is limited due to rapid infiltration of rainfall into the sandy soils.

Surface water run-off in the dune-covered western part of the site is negligible. Swampy areas are found within some of the closed depressions in the east-central portion of the site.

2.4.2 Ground-Water Hydrology Regional Ground-water supplies in the region are obtained primarily from shallow wells, which terminate in the more granular glacial deposits. The predominantly shale bedrock in southwest Michigan is not recognized as an aquifer. The deeper bedrock strata are known to contain brines and are not used as sources of ground water. Some larger towns near the lake, such as Benton Harbor, obtain their water supplies directly from Lake Michigan.

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The water sources, as of December, 1999, for Parks, Public Facilities and Communities within ten (10) miles of the site are given in the following table:

Distance From Plant Source of Capacity in Number of Storage Capacity Place In Miles Drinking Water gpd People In Gallons St. Joseph 9.0 Lake Michigan 16,000,000 27,500 4,850,000 1500 ft. Offshore City of 2.5 Crib 300 ft. 1,400,000 2,000 600,000 Bridgman Offshore Lake 0.6 Lake Michigan 2,000,000 10,000 1,000,000 Township 2400 ft. Offshore

There are a large number of private domestic wells (estimated 4000) in the area within the ten (10) mile radius. The nearest is 2,160 feet from the plant. There are no residences on the site property.

Covert Ridge is a ground-water barrier as well as a watershed boundary between the glacial plain to the east and the Grand Marais Embayment to the west.

Static ground-water levels east of the ridge are generally at Elevation 650 feet above sea level.

In contrast, static water levels west of the ridge occur generally at elevations of 580 to 490 feet above sea level. The chemical characteristics of the ground water on each side of the ridge are also different.

Local Three existing wells are located within 1,500 feet of the southern boundary of the site, and approximately 20 wells are found within 1,500 feet of the northern site boundary. In addition, 25 residences are supplied by a number of the shallow wells in Thornton Valley approximately one mile northeast of the property. These wells are generally 20 to 30 feet deep and have a static water level of 586 feet above sea level. No wells are located between the site and Convert Ridge to the east. At the site, the water table occurs within the dune and beach sands which overlie impermeable lake deposits. Recharge of ground water by infiltration of precipitation through the

Lake Township serves Warren Dunes State Park and is interconnected with the City of Bridgman and the Township of Chicaming.

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permeable sandy surficial soils is rapid. Static water table elevations observed inside perforated plastic pipe installed in 19 test borings at the site ranged from 582 to 609 feet above sea level.

Slightly higher levels probably occur beneath the higher dunes, particularly after rainy periods.

The overall gradient of the water table, except in the eastern-most part of the site, is toward the west. The direction of ground-water flow for most of the site is, therefore, westward to Lake Michigan. The ground-water divide between Thornton Valley and the dunes area is close to the topographic divide, some 3,500 feet east of the lake. Consequently, only minor ground-water seepage escapes into Thornton Valley, and this seepage originates from the extreme eastern part of the site. The water table gradient is very flat with typical values of 0.5 to 0.7 percent in the dune area and 1 to 4 percent close to the lake front. Consequently, the rate of ground-water flow under these conditions is extremely slow. Inplace field permeability tests indicate an average permeability of the upper sands on the order of one to two feet per day with a maximum measured value of three feet per day. The deposits beneath the sands are impermeable. Since the water table gradient is small and since the ground-water flow from the west and central portions of the site is not in the direction of existing ground-water supplies but is toward the lake, the possibility of accidental spillage of liquids in the plant area affecting ground-water supplies is remote.

2.4.3 Summary of Conclusions Based on the hydrologic studies conducted at the site, the following conclusions have been reached:

a. The site is located within the Grand Marais Embayment and is distinctly separated from the area to the east by Covert Ridge which is a surface drainage divide and a groundwater barrier.

b. The hydrologic study, as part of the application for a permit for the initial construction of the plant, found that infiltration of rainfall into the sandy surficial soils at the site was rapid and flooding conditions were non-existent.

c. Surface runoff is minor and is restricted to the eastern portion of the site. The minor runoff discharges into Lake Michigan via Thorton Valley and the Grand Marais Lakes. The rest of the site is characterized by basins of interior drainage and is devoid of streams. Shallow swampy areas occupy depressions between coalescing sand dunes in the eastern part of the site.

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d. The ground-water table generally rises gradually eastward away from Lake Michigan. The water table is less than 30 feet above the level of the lake and occurs within the dune sand or beach sand which overlies impermeable glacial lake clays. Local mounding of the water table occurs beneath some of the higher dunes and beneath the turbine room absorption pond.

e. Beneath most of the site, including the plant areas, the overall direction of ground-water flow is toward Lake Michigan. East of the topographic divide, some 3,500 feet east of the lake, the direction of ground-water flow trends northeast into Thornton Valley.

f. The water table gradients are very flat and the rate of ground-water movement consequently is slow.

g. The possibility of affecting wells or the available ground-water resources in the site area by construction and operation of a nuclear facility located in the west -

central portion of the site is extremely improbable.

h. The hydrologic characteristics of the site are, therefore, favorable for the location of a nuclear power plant.

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2.5 ENGINEERING SEISMOLOGY

The site lies in a region which has experienced very little earthquake activity. No major earthquakes have had epicenters closer than about 400 miles to the plant site. There has been some minor earthquake activity closer to the site; however, no shocks within 50 miles of the site have been large enough to cause significant structural damage. A complete report of site seismology is included in Appendix A to the Preliminary Safety Analysis Report.

2.5.1 Seismicity The epicentral locations of all reported earthquakes with Modified Mercalli Intensities of V or greater in the region surrounding the site are shown on Figure 2.5-1, Epicentral Location Map.

The closest Intensity IV shock is also shown. Only three recorded earthquakes with epicentral intensities of V or greater have occurred within approximately 100 miles of the plant site. These were of relatively low intensity, barely strong enough to cause even slight structural damage.

The two largest earthquakes in the vicinity of the site had maximum intensities o f VI. The first occurred near Fort

Dearborn (Chicago) Illinois,

about 70 miles from the site, in 1804. The second occurred in south-central Michigan about 75 miles from the site, in 1947. An Intensity V earthquake occurred near Milwaukee, Wisconsin in 1947. A weak earthquake with a maximum intensity of IV occurred in 1938 on the south shore of Lake Michigan about 30 miles from the site. This earthquake did no damage but was felt over a relatively large area.

A possible earthquake occurred in 1883 near Kalamazoo, Michigan about 50 miles northeast of the site. The maximum intensity for this event is listed as VI since there is a record of some minor damage in Kalamazoo. However, information is available which indicates that the damage may have been caused by an explosion and not an earthquake.

It is likely that most of the minor earthquake activity in the Michigan Basin is related to readjustments along zones of weakness in the bedrock, probably caused by glacial rebound. This same mechanism probably caused the minor earthquakes reported in northern Ohio, Lake Erie and western New York State. The 1947 earthquake in south-central Michigan may be related to a possible northwest trending fault located 50 miles northeast of Benton Harbor. Other seismic activity is related to fault systems bordering the Michigan Basin such as the Findlay Arch System in western Ohio. Some of the larger shocks from this area have been felt in southern Michigan.

In summary, it may be stated that the seismicity of the region is low. Although no major earthquake has originated closer than about 400 miles to the plant site, several damaging shocks INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 29 of 87

have occurred close enough to be of significance. A list of the closest significant earthquakes in the region is presented in Table 2.5-1, Earthquakes with Epicenters located within 200 miles of Plant Site.

While several of these shocks were possibly felt in the vicinity of the site, no damaging effect would have been experienced from them. In the event of a recurrence of an historical earthquake, no damage would be experienced at the site by reasonably well-designed structures.

2.5.2 A Seismic Design Foundation Materials The site is underlain by a simple sequence of formations consisting of a surface stratum of dune sand underlain by dense beach sands, a stiff clay stratum and, glacial till resting on shale-bedrock. Major plant structures are supported on mat foundations installed on the overlying compact sand, recompacted sand, or stiff clay deposits.

Available data from past earthquakes indicate that compact glacial till and competent bedrock perform well under dynamic loading. Dynamic laboratory testing on samples of the compact beach sand and the upper lake bed deposits of silty clay indicates that these materials would experience no significant loss in strength during any potential earthquake.

Operating Basis Earthquake On the basis of the seismic history of the area, it appears extremely likely that the site will not experience any significant earthquake motion during the life of the plant. Based on the history of previous earthquake activity in the area, it is estimated that the maximum ground motion to which the site may be subject during its life would be due to a shock similar to the 1947 south-central Michigan earthquake. It is estimated that the magnitude of this shock was no greater than about 41/2 on the Richter Scale. This earthquake possibly may be related to a postulated fault structure trending northwest-southeast through southwest Michigan. The closest approach of this postulated structure to the site is about 50 miles to the northeast. It is estimated that the ground acceleration at the site due to a magnitude 41/2 earthquake at a distance of 50 miles would be barely perceptible at the site. The largest earthquake in the region occurred near Lima, Ohio, in 1937. It has an epicentral Intensity of VII to VIII and was felt over an area of about 150,000 square miles. The magnitude of this earthquake has been estimated at about 51/2. This earthquake was related to local faulting associated with the Findlay Arch. The closest approach of the Findlay Arch or any related structure to the site is about 130 miles. An earthquake of magnitude 51/2 at an epicentral distance of 130 miles would be barely perceptible at the site. On a INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 30 of 87

historical basis, it does not appear necessary to incorporate a seismic factor in the elastic design of the power plant. However, in view of the nature of the facility, the major structures are conservatively designed for a maximum horizontal ground acceleration of 10 percent of gravity and a maximum vertical acceleration of 6.66 percent of gravity. The seismic design requirements of the reactor containment structure are given in Chapter 5 and the requirements for other structures and equipment are given in Sub-Chapter 2.9. The dynamic analysis of the containment structure for seismic loading is in Appendix F to the Original Safety Analysis Report.

Design Basis Earthquake The maximum potential earthquake for this site is considered to be a recurrence of the largest recorded earthquake in a nearby region at the closest epicentral distance consistent with geologic structure. A number of earthquakes in the region have not been related to known tectonics.

These shocks may have their origin in the crystalline basement rock where the structure is complex. They may occur along zones of weakness, triggered by glacial rebound. Historically, such shocks have been minor, with estimated magnitudes not exceeding 41/2. However, an earthquake in 1943 with its epicenter in Lake Erie may have had a magnitude as great as 5. The geology of Lake Erie is similar to that of southwest Michigan in that the bedrock is essentially a stable platform with little or no seismic history and no known faulting. Shocks in the Lake Erie area are probably related to glacial rebound, as we believe the shocks to be in the area of the site.

Based on the foregoing, it has been conservatively assumed that the maximum potential earthquake could be as large as Magnitude 5 and might occur relative to some yet unknown geologic structure in the bedrock near the site, perhaps triggered by glacial rebound. Assuming such a shock might have a focal depth as shallow as 10 kilometers, it is estimated that the maximum ground acceleration at foundation level (within the lake or beach sand deposits) at the site would be about 15 percent of gravity. However, additional margin has been provided for by designing the engineered safety features to be operative under a maximum horizontal ground acceleration of 20 percent of gravity and maximum vertical acceleration of 13.33 percent of gravity.

The seismic design requirements of the containment are given in Chapter 5, and the requirement for other structures and equipment are given in Sub-Chapter 2.9.

Response Spectra Recommended response spectra showing responses for typical percent of critical damping for the operating basis and the design basis earthquakes, corresponding to horizontal ground INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 31 of 87

accelerations of 10 and 20 percent of gravity, are presented on Figures 2.5-2 and 2.5-3. These response spectra represent the maximum amplitudes of motion in structures having a range of natural frequencies subjected to earthquake ground motion.

The use of the average (El-Centro) response spectra as presented in TID 7024, normalized to the recommended ground accelerations, was deemed appropriate for this site since the average spectra are based on site conditions consisting of a deep thickness of overburden soil over bedrock. The subsurface conditions at the Cook Plant site consists of soils which are comparable in compactness to El-Centro and it was therefore felt that the normalized El-Centro spectra are appropriately conservative for this site.

In order to show that the response spectra generated, using four earthquakes, are as conservative as the spectra generated using a synthetic earthquake, which falls above the site spectra, a comparison was made for the Auxiliary Building, between existing floor spectra and the spectra generated using the modified El-Centro Earthquake (N-S-components - 1934).

The El-Centro earthquake was modified such that at all frequencies its response spectrum falls above the site response spectrum. (See Figure 2.5-3a.)

Figures 2.5-3b through 2.5-3e show this comparison for various elevations in the structure for an OBE. Curve - A represents the spectrum used in design and curve - B represents the spectrum generated using the synthetic time history motion. Since curve - A envelopes curve - B in all cases the response spectra used in design are conservative.

Figures 2.5-3f through 2.5-3j show this comparison for the DBE with 5% structural damping.

For the Dry Cask Storage Project, the Maximum Critical Load (MCL) rating of the east auxiliary building crane was increased to 145 tons. For this specific effort, new ground response spectra for the auxiliary building were developed using the guidance in Regulatory Guide 1.60, Revision

1. Spectra shapes from this Regulatory Guide were anchored at 0.lg OBE and 0.2g SSE zero period ground acceleration. In addition, the original real time histories from the four historical earthquakes were replaced with synthetic time-histories which were developed in three directions (two horizontal and one vertical). The design artificial time history function enveloped the Regulatory Guide 1.60, Revision 1 design ground response spectrum for all damping values from Regulatory Guide 1.61, Revision 1.

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Supplemental Data Subsequent to the detailed studies of the site and its surroundings described in the Appendix A, additional work was performed to confirm the validity of the seismic accelerations proposed as design bases for the plant.

An investigation was made of the logs of a series of gas and oil wells drilled in the site vicinity to depths of up to 2500 feet and the results were plotted. Although fifteen logs were studied, eleven lay along a southwest-northeast axis about 35 miles long, roughly parallel to the lake shore and passing about two to three miles from the plant location. The remaining five were located along an axis perpendicular to the first and intersecting it in the site vicinity.

The results of this study demonstrated that there is a complete absence of geologic structure in the immediate site area which could be related to past or future seismic events.

In addition, a large number of references were studied to determine the seismic characteristics of the region surrounding the site. This included eastern Wisconsin, northern Illinois and Indiana, and northwestern Ohio as well as Michigan.

Further information relating to the selection of seismic parameters can be found in the reports of the results of foundation investigations conducted at the site, by A. & L. Casagrande:

Report on Foundation Investigation for Donald C. Cook Nuclear Power Plant, 2/20/68 Donald C. Cook Nuclear Power Plant Settlement Analyses of Containment Units Based on Investigation of Undisturbed Samples from Boring No. 105, 5/4/68 Report on Foundation Investigations for the Donald C. Cook Nuclear Power Plant, 8/26/68 Supplement to Report of August, 1968 on Report on Foundation Investigation for the Donald C. Cook Nuclear Power Plant, 4/69 2.5.3 Conclusions It is anticipated that the site will not experience any significant earthquake motion during the life of the nuclear facility. Historically, there is no basis for expected ground motion of more than a few percent of gravity. However, as a conservative basis, an earthquake horizontal ground acceleration of 10 percent of gravity was adopted for plant design where applicable.

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For safe shutdown of the reactor, and operability of engineered safety features a maximum horizontal ground acceleration of 20 percent of gravity was assumed. This ground acceleration is in excess of that estimated on the basis of an occurrence of a shallow focus Magnitude 5 earthquake close to the site. On the basis of the seismic history and the known tectonics of the area, the possibility of such an occurrence is extremely remote.

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2.6 LIMNOLOGY AND ECOLOGY 2.6.1 Limnology and Ecology Introduction Lake Michigan is the condenser cooling water, component cooling water, and service water for Cook Nuclear Plant. Lake Township Fire Hydrant System is the back-up fire protection source water for Cook Nuclear Plant. Radioactive liquid wastes generated by the plant are processed in the liquid radioactive waste system and the processed stream is discharged within the plant to the circulating water system discharge stream. All effluent streams from the liquid radioactive waste system are sampled and analyzed prior to the discharge and monitored during the discharge in accordance with the regulations in 10 CFR Parts 20 and 50.

The Cook Nuclear Plant withdraws 1,645,000 gpm for cooling water and plant process water from Lake Michigan. Heat with small amounts of chlorine used for biofouling control, radioactivity in the liquid radioactive waste system outfalls, and blowdown from the steam generators are the primary additions to the plant effluent water. Heat rejection rates for Units 1 and 2 are - subject to variations depending on plant efficiency. The maximum allowed heat rejection rate for plant total is 16.8x109 Btu/hr.

Potential impacts to the limnological and ecological features of the region from the operation of Cook Nuclear Plant include thermal stress to lake biota, fish and macrobenthos impingement on traveling water screens, entrainment of planktonic biota through the plant and into the thermal plume, alterations to local water and sediment chemistry, thermal plume induced shore ice melts, meteorological changes, bathymetric changes, biocide toxicity, and increases in water and sediment radioactivity.

Research programs to determine the interactions between the Cook Nuclear Plant and the Lake Michigan environs were begun in 1966 and continue to the present. These research studies were conducted in three phases. From 1966 until 1973, the limnological investigations were conducted primarily to provide information for the environmental impact statement. Research conducted from 1973 through 1982 was required by the Nuclear Regulatory Commission license Appendix B Technical Specifications and was needed for certain provisions of the State of Michigan issued National Pollution Discharge Elimination System (NPDES) Permit. The last phase of research, which continues to date, is mostly monitoring of certain baseline conditions established in the first two phases and new conditions, specifically the introduction to the Cook Nuclear Plant vicinity of Lake Michigan of the biofouling molluscs, Asiatic clams (Corbicula fluminea) and zebra mussels (Dreissena polymorpha). The results of the first and second phase INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 35 of 87

studies were compiled in reports prepared by the consultant or were reports placed in the Donald C. Cook Nuclear Plant Annual Environmental Operating Reports starting in 1974 through the present.

The three phases of studies were conducted in numerous segments and were reported on in numerous reports but they can be grouped in general categories and the results of these studies will be grouped by category within the three phases of study. The following sections identify the category groupings of the studies by phases. Within the category grouping is a brief identification of the types of studies within the grouping, the purpose of doing the studies, and the significant results and conclusions of the studies within the category group.

2.6.2 Initial Studies 2.6.2.1 Study Groupings Physical Limnology Physical limnological studies conducted in Lake Michigan near the Cook Nuclear Plant included lake bathymetry, sediment stability and physical characteristics, ice formation and melting patterns, seiches, and a special subset of the physical limnology that dealt with thermal plume dispersion. Thermal plume dispersion studies included wind, wave, and lake current studies, dye dispersion studies; mathematical and scale modeling of the thermal plume dispersion; and locating potable water intakes and determining the possibility of the thermal plume reaching those intakes.

Biological Studies Biological studies covered periphyton, phytoplankton, zooplankton, benthic invertebrate, and psammolitoral fauna community composition and abundance and benthic invertebrate and sediment chemistry interactions.

Sediment Chemistry Sediment chemistry studies included determination of the baseline concentrations of radioactive and non-radioactive elements in the Lake Michigan sediments.

Water Chemistry Water chemistry studies include determinations of radioactive and non-radioactive element concentrations in Lake Michigan.

Table 2.6-1 is a list of the references used to compile the initial phase studies summary.

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2.6.2.2 Purpose of Initial Phase Studies Physical Limnology The physical limnological studies were conducted for many reasons. Bathymetry and sediment size composition and distribution was studied to determine the baseline lake bottom contour conditions and use this information to determine if plant operation would alter the bottom contours near the intake and discharge structures. Sediment stability determinations were made using sediment particle size, composition and distribution. This gave the intake and discharge design engineers information on the scour potential of the lake sediments. Sediment size can also be used to correlate benthic macroinvertebrate population distribution and density to physical characteristics.

Ice formation and ice melting of the floating and shore ice was important in determining the potential for ice damage to plant equipment. These studies also provided the baseline data to determine if the thermal discharge would cause shoreline erosion by melting the shoreline that protects the beaches from wave erosion during winter storms.

Seiches were studied to determine the possible effect on equipment and the potential for flooding of equipment.

Thermal plume dispersion studies were conducted to determine the direction the thermal plume would curve, whether the thermal plume would impinge on the beach, the area within thermal isopleths, and the distance the heated water would travel in the lake.

Biological Studies Biological studies were conducted to determine the effect of the thermal discharge on algae growth and on zooplankton populations. Benthic macroinvertebrate studies were conducted to determine the effect of chemical discharges from the plant on this organism group.

Sediment Chemistry Sediment chemistry studies were conducted to determine if the Cook Nuclear Plant vicinity in particular and Lake Michigan in general were contaminated from anthropogenic trace element sources and to establish the background levels of the radioactive and non-radioactive elements so these concentrations could be compared with levels measured after plant operation began.

Water Chemistry Water chemistry studies were conducted to determine if the Cook Nuclear Plant vicinity in particular and Lake Michigan in general were contaminated from anthropogenic trace element INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 37 of 87

sources and to establish the background concentrations of radioactive and non-radioactive elements so these concentrations could be compared with levels measured after plant operation began.

2.6.2.3 Initial Study Results Physical Limnology Figure 2.6-1 is a plot of the bottom of the lake adjacent to the site. It is characterized by gentle and regular topography. The 100- foot depth isopleth lies about six miles from shore. Isopleths are generally regular and parallel to the shoreline. Two sand bars lie close to shore along the entire length of the site property. The inner bar averages about 500 feet from the shoreline while the outer bar runs approximately 1000 feet from the shoreline. Maximum water depth of five to six feet is present between the inner bar and the shore. Twelve to thirteen feet of depth is the greatest measured between the bars. The depth over the crest of the inner bar is about four feet, while the outer bar peaks at eight to nine feet beneath the surface.

A number of studies of bottom stability along the east shore of Lake Michigan have been made in the past decade or two. Lake Michigan has what appears to be very stable conditions near shore despite severe storms and winter icing. Present evidence indicates that the nearshore sandbars fluctuate in position but maintain a fairly consistent average position, with fairly consistent water depths over their crests. Though bottom contours remain relatively stable, the littoral transport of sand has been estimated to be 100,000 cubic yards per year moving generally southward along the Michigan shore.

Although all of the currents of Lake Michigan are not thoroughly understood, certain of the larger features have been found with a surprising degree of constancy. There is a general outflow current along the Michigan shore from Little Sable Point northward toward the Straits of Mackinac, and there is a large eddy near the eastern shore near Benton Harbor, Michigan.

Figure 2.6-2 indicates the results of several studies made of lake currents. In addition to the gross current features, there appears to be a thin, elongated, counterclockwise eddy close to the shore between Michigan City, Indiana and Benton Harbor (indicated by X on Figure 2.6-2).

Some discussion on natural cyclic lake level fluctuation is warranted.

The speed and direction of local water currents in the site vicinity control the movement and dispersal of plant thermal plume. Studies (Reference 4) indicated that alongshore currents are established and controlled by interactions between local winds and the regional current pattern.

Local winds are the dominant factors in establishing alongshore currents.

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Lake levels tend to follow cycles. Over the past fifty years, periods of high lake levels and erosion were experienced from 1951-55, 1969-1975, and 1983-1987. The all-time maximum (monthly mean) high water level during this period was recorded in 1986 at 583.1 (NGVD).

The lowest recorded (monthly mean) level of the lake was 576.8 feet above mean sea level (NGVD) during the 1964-65 winters; the highest (monthly mean) high lake level was 583.6 feet above mean sea level (NGVD) during the summer of 1886.

An Illinois State Geological Survey report (Reference 3) cites that where lake levels are rising above the 579 ft. IGLD level, well-developed beaches will delay the onset of maximum bluff erosion until they are depleted. After beaches have been depleted, bluff erosion from wave attack progresses fairly rapidly. Bluff erosion generally does not immediately decrease with decreasing lake levels, even when they fall below the 579 ft. level. Commonly, there is a lag effect by which recession rates are maintained or accelerated because slopes remain exposed until vegetation can become firmly established.

The Cook Nuclear Plant is protected by a sheet piling wall which runs the entire length of its lake frontage from the north to south property lines. A second row of sheet piling runs parallel and 35 ft. west of the first line of piling and spans the length of the protected area.

Figure 2.6-3 is a plot of surface water temperatures in Lake Michigan during the relatively cool year of 1965 and the relatively warm year of 1966. Temperatures rise abruptly from a 32°F icing condition in winter to a peak in July and August and then decrease linearly to ice-water temperatures by late December.

Cook Nuclear Plant elevations are expressed in National Geodetic Vertical Datum (NGVD).

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A number of southwestern Michigan municipalities use Lake Michigan as their potable water source. These intakes and their approximate distances from the plant discharge are as follows:

Northward South Haven 32 miles Benton Harbor 11 miles St. Joseph 9 miles

Southward Lake Township 0.6 miles Bridgman 2.5 miles New Buffalo 16 miles Grand Beach 18 miles Michigan 19 miles Unknown 22 miles Michigan City, Indiana 25 miles

To the north, the outflow of the St. Joseph River interposes a physical and dynamic barrier to further progress of effluent northward along the shore. The plant effluent plume could reach the water intakes to the south at Lake Township and Bridgman. These intakes are also of the infiltration type. However, the prevailing winds of summer, when the worst dilution conditions (minimum wind and wave section) exist, are expected to carry the plume north from the plant and away from these water intakes.

Seiches are oscillations in the level of lakes and similar bodies of water caused by the passage of squall lines across the body of water. In Lake Michigan, these squalls have their fronts oriented NE to SW and are accompanied by an abrupt increase in barometric pressure and local high winds. Although seiches occur frequently in the Great Lakes, the great majority are only a few inches in amplitude. A large seiche occurred on June 26, 1954 and caused water level increases of up to 10 feet at North Avenue in Chicago, Illinois. The greatest level increase recorded on the lake's eastern shore was 6 feet at Michigan City, Indiana.

The maximum recorded amplitude of an open lake seiche was 4.2 feet observed at the Wilson Avenue Crib in Chicago on July 6, 1954. A previous seiche on June 26, 1954, which resulted in a rise of 3.2 feet at Wi lson Avenue Crib, caused the rise estimated at less than 6 feet in the Michigan City yacht basin, a point approximately 25 miles south of the plant site in an area where seiche effects are considered more severe than those farther to the north. Taking these INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 40 of 87

values in proportion, one can postulate the maximum seiche producing a water level increase of as much as 8 feet in the Michigan City yacht basin.

To determine the plant elevation necessary to protect the plant from flooding due to seiches, the characteristics of the lake shore at the plant, historical meteorological conditions, and mathematical modeling were used to determine a maximum seiche of 11 feet. This equates to a plant elevation of 594.6 feet above mean sea level (NGVD).

The plant is flood protected from the maximum (monthly mean) high lake water level; however, a design basis seiche occurring when the lake is at its maximum recorded level will cause flooding in the Turbine Building Screen-house. Safety-related components located in the Turbine Building Screen-house have been evaluated for the condition and flood sensitive components have been protected. Therefore protection has been provided for safety-related equipment from flooding, waves, ice storms and other lake related hazards.

Wind generated waves are limited in their dimensions by wind velocity, duration and fetch. The greatest Lake Michigan fetch for the plant site is 265 miles to the north. The maximum deep waterwave is approximately 23 feet, and would require a sustained north wind of about 26 knots for over 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />. The runup of such a wave on the site shore, discounting the effects of the off-shore sandbars, has been calculated as 3.7 feet. This figure is overly conservative, however, since the large wave approaching the beach would be tripped by each of the sand bars.

The coincidental occurrence of maximum wave and maximum seiche was evaluated and determined not to be a possible event.

Seiches are produced by squall-line weather and maximum waves by many hours of sustained wind.

Biological Studies The Lake Michigan flora and fauna (excluding fish) were studied during the initial phase and was found to be similar to other very large, oligotrophic North American lakes. Phytoplankton, zooplankton and benthic macroinvertebrate communities were diverse. The psammolitoral community was fairly diverse, and several taxa were at times very abundant. The environment of the psammolitoral community is very harsh and unstable. Population fluctuations were large over short time intervals.

Phytoplankton in Lake Michigan was dominated by diatoms followed by green algae. Densities of total cells ranged from 20,000 to over 8 million cells per liter, depending upon station, water depth and season.

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Periphyton, attached algae, was sparse near Cook Nuclear Plant. The lack of substrate was a major cause. Most periphyton were diatoms with green algae making up a minor portion of the standing crop.

Zooplankton in the Cook Nuclear Plant vicinity were abundant and fairly diverse. Early samples were collected with a net that was too coarse. Collections using the proper net mesh produced samples with at least 24 taxa of copepods, cladocerans and rotifers with total densities between 5,000 and 90,000 animals per liter.

Benthos studies in the early stages were descriptive and date interpretation was intuitive rather than statistical. Pontoporeia affinis, tubifex sp., Limnodridus sp., and Pisidium were the dominant taxa. Abundance and species composition varied greatly with station (water depth) and season.

The concentration of trace elements in the biota showed no specific pattern. The levels of mercury in phytoplankton, zooplankton, benthos and fish were quite low compared to Lake St.

Clair and Lake Erie. Selenium was slightly eleva ted in three zooplankton samples but not in benthos or phytoplankton from the safe station. Estimates made of the concentration of radioisotopes in invertebrates of Lake Michigan, at the highest, will reach values equal to 8% of the upper limiting concentration normally applied to fish.

Sediment Chemistry Sediment chemistry study results showed the sediments to be comparable to sediments in water bodies of the world. There were no trace elements or radioisotopes present in concentrations higher than values obtained from uncontaminated water bodies.

Water Chemistry Water chemistry studies showed the concentrations of trace elements, both radioactive and non-radioactive, to be very similar to concentrations measured in uncontaminated water bodies around the world except for chromium and zinc concentrations near the Grand River. Trace element concentrations in water near the Cook Nuclear Plant were at background levels for the Great Lakes.

2.6.3 NRC Technical Specification, Appendix B Phase Studies (1973 -1982)

This study phase was predominately research and monitoring required by the Technical Specifications, Appendix B of the plant operating license issued by the Nuclear Regulatory INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 42 of 87

Commission, but not exclusively. Some studies were conducted under requirements of the National Pollution Discharge Elimination System Permit issued to the plant by the Michigan Water Resources Commission. The majority of the research was conducted by the University of Michigan with the private consulting firm ETA Engineering, Inc. and the Cook Nuclear Plant staff conducting the thermal plume mapping and bathymetric surveys.

Many studies begun during the initial phase were continued during this phase. These studies provide the plant operational data to compare with the pre-operational data gathered during the initial phase studies. Table 2.6-2 is a bibliography of the reports published during this phase of study at the Cook Nuclear Plant.

2.6.3.1 Study Groupings Physical Limnology Studies These studies include the shore ice formation and melt studies, the lake current and temperature study using in situ monitors, the study of the effects of the thermal plume on local meteorology, the thermal plume mapping studies and the bathymetric studies.

Biological Studies These studies include continuations of the periphyton, phytoplankton, zooplankton and benthos studies of species composition and abundance. Fish studies of population size and species composition were initiated.

Sediment Chemistry Studies Sediment chemistry studies included the non-radiological elemental composition of the sediments. Radiological elements were also monitored for the increase in certain radioactive isotopes.

Water Chemistry Studies The water chemistry studies included analyses for pH, hardness, conductivity, phosphorous, total nitrogen, sulfate, ammonia and trace metals.

2.6.3.2 Purpose of Technical Specification, Appendix B Studies The Technical Specification Appendix B is part of the Cook Nuclear plant operating license that regulated the radiological and non-r adiological environmental monitoring, aquatic ecological studies of the post-startup impacts to Lake Michigan, and regulated plant effluents, both radiological and non-radiological. Radiological issues are now addressed in the Off-site Dose INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 43 of 87

Calculation Manual. The non-radiological issues remain in the Appendix B Technical Specifications, whose objectives are to:

Verify that the station is operated in an environmentally acceptable manner, as established by the FES and other NRC environmental impact assessments.

Coordinate NRC requirements and maintain consistency with other Federal, State, and local requirements for environmental protections.

Keep NRC informed of the environmental effects of facility construction and operation and of actions taken to control those effects.

Environmental concerns identified in the FES, which relate to water quality matters are regulated by way of the Plant's NPDES permit.

Physical Limnological Studies The ice studies were continued to determine how the thermal discharge affected the shore ice and the floating ice in front of the plant. Winter storms could potentially cause severe beach erosion if the thermal plume melted the floating ice and the ice foot (the ice frozen to the bottom at the water/substrate interface) exposing the beach to winter storm generated waves.

A five-year meteorological study was conducted at Cook Nuclear Plant to determine if the operation of the once-through lake water cooling system would significantly effect the natural temperature, moisture, precipitation and fog conditions inland from the plant and, if so, how and to what extent these climatic conditions are affected. This investigation was undertaken because of the absence of quantitative information on the meteorological effects of near-shore warm water plumes. The local economy is heavily dependent on agriculture, especially fruit crops.

Changes to the local weather conditions could have a serious impact on the local economy.

Thermal plume mapping studies were conducted to determine the aerial extent of the 3F° and 1F° isotherms and the 3F° plume volume. This information was needed to determine if the plume would impact potable water intakes north and south of the plant, if the thermal plume would sink in the winter and impact the benthos and if the thermal discharge would comply with the 570- acre areal limit imposed by the state issued NPDES Permit. The lake current and temperature studies were used to help interpret the thermal plume mapping studies and evaluate the accuracy of the mathematical plume dispersion model. Knowing the size of the thermal plume also helped aquatic biologists determine how much aquatic habitat was impacted by the plume. Knowing the plume dimensions and location also helped the research team from the University of Michigan evaluate causes of changes in fish populations near the plant.

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The bathymetric studies were conducted to determine if the lake water intake and discharge structures caused sediment erosion outside of the rip-rap aprons around these structures.

Biological Studies The biological studies of the abundance and distribution of periphyton, phytoplankton, zooplankton and benthos were continued from the initial phase studies to provide the pre-operational and operational data comparisons. Fish studies were initiated in 1973 and were fully implemented in 1974. These studies were conducted to determine the impact of the Cook Nuclear Plant from construction and operation. Construction related impacts include the habitat alteration resulting from increased silt run-off from the construction site, placement of rip-rap around the intake and discharge structures and burying of the intake and discharge tunnels in the lake bed. Operational impacts could result from oil and chemical spills, thermal discharges, the impingement of fish and benthos (crayfish) on traveling screens and the entrainment of planktonic organisms (phytoplankton, zooplankton, benthos and fish eggs and larvae) through the cooling water system. The combined impacts of the plant construction and operation were studied by analyzing the biological community structure for changes in species diversity and abundance. Primary production was estimated using the C-14 method; a measure of the effect of plant effluents on algae cell function. The health of algae cells entrained through the plant was assessed by measuring chlorophyll to phaeophytin ratios. Zooplankton could be impacted by the Cook Nuclear Plant thermal plume or by entrainment through the cooling system. Heat and mechanical damage caused by turbulent water flow through the system are the major effects.

Benthos were studied to determine the impacts of heat, habitat alteration, impingement on travelling water screens and plant entrainment caused by Cook Nuclear Plant operation.

Changes in species composition and abundance was the measure used to determine effects.

Fish were studied to determine the effects of the thermal plume on adult and juvenile fish distributions, the impact of adult and juvenile fish impingement on travelling water scre ens, and the effects of fish egg and larvae entrainment through the power plant.

Sediment Chemistry Studies The sediment chemistry studies were conducted to determine the changes in sediment chemical composition due to chemical discharges from the plant and from the possible build-up of organic material due to the settling and decomposition of aquatic biota killed by the Cook Nuclear Plant thermal plume or plant entrainment.

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Water Chemistry Studies Water samples were collected and analyzed for phosphorus, dissolved silica, nitrate, nitrite, chloride, sulfate, oxygen saturation, alkalinity, pH, conductivity and these trace metals: Ba, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Sr and Zn. In addition, a detailed study of the thermal bar was conducted to determine if it is a barrier to mixing of onshore with offshore water and, if so, how great did the chemical gradient become before the thermal bar moved far offshore.

2.6.3.3 Results of Technical Specification, Appendix B Studies All results reported below are from Publication 22 from the University of Michigan unless noted otherwise.

Physical Limnology Studies Ice studies were conducted over a ten-year period from the winter of 1969-1970 through 1979-1980. A method of photographing the ice formation and analyzing the photographs was developed so the distance from the camera and the elevation of the object could be determined with reasonable accuracy. The conclusions of the ice study were:

1. The data show that the offshore ice ridges, offshore breakers and breaker zones, three characteristic features of the Lake Michigan shoreline in front of Cook Nuclear Plant, are coincident.

Ice ridges appear to be grounded features of the near shore ice complex and they serve a dual role. They protect the beaches from incoming wave energy when present and, during the breakup of the complex, may modify the topography in the offshore bar vicinity.

2. The stages of ice development appear not to be controlled by any single meteorological variable but by a complex interrelationship between ice development and meteorological conditions. Air temperatures below freezing were found to be a necessary condition for initiation of the ice foot. Growth of the ice complex was associated with westerly winds and deterioration with easterly winds.

3. The plant's thermal plume produced a melthole that ranged from 0.1 to 0.5 square miles in size. The melthole was restricted to the vicinity of the discharge area.

The ice ridges closest to the shoreline were minimally affected by the melthole and the effectiveness of the "ice ridge" complex as a wave energy dissipator to protect the beach was not significantly altered.

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4. North and south of the melthole there was no noticeable change in the normal ice complex of ridges and lagoons and the nearshore ice complex was not discernibly altered due to the presence of the plant thermal plume.

Lake current studies were used to help analyze the thermal plume mapping data. Lake currents near the plant were the single most important physical parameter affecting the position, size and trajectory of the thermal plume. The lake current data were needed to determine the probability of the plume influencing other water intakes, recirculation to the Cook Nuclear Plant intakes and contacting the beaches north or south of the plant. The in situ current meters were moored about 1m from the bottom of the lake in four locations (see Figure 2.6-4). Surface drogues were used on the days thermal plume mapping surveys were conducted to determine surface current direction and speed.

Current speed and direction recorded by the four instrument units were compared by correlation analysis. Current speeds recorded by the four units generally correlated. Better correlations of speed were obtained when the two inshore data sets and the two offshore data sets were compared. Short-term comparisons among the meters showed very poor current speed correlation.

Current direction measurements among the four current meters showed very poor correlation. A typical current correlation is illustrated by the north inshore and offshore meters for the period November 29, 1977 to December 19, 1977. The two meters recorded current direction differences equal to or greater than 105° more than 50% of the time.

Surface current direction measurements made with the drogues too often showed the bottom current and surface current flowing in different directions.

The lack of good correlation between lake current speed and direction illustrates the unpredictability and complexity of the physical forces affecting the thermal plume in the inshore region of Lake Michigan.

Current direction persistence analysis showed more consistent patterns than did current direction analysis. Nonetheless, variability did exist. In 1977, currents persisting less than one day in any direction occurred 68% to 81% of the time at all four meters. Total current persistence was similar for 1-2, 2-3 and 3-4 days at all four meters and with the exception of the north nearshore meter, flows to the north were more frequent and persisted longer than in any other direction. In 1979, however, current persistence in one direction for less than one day ranged from 10% to 55% of the time. North flowing currents at all stations were more frequent and persistent than INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 47 of 87

other directions, but only slightly. Current direction persistence variability was least in 1977 and 1978 and greatest in 1979. Current direction persistence analysis also illustrates the complexity and variability both spacially and temporally of the physical forces of inshore Lake Michigan.

Lake temperature data was collected in situ using three instrument units located north and south of the plant and west of the intake structures (Figure 2.6-4). The instrument units consisted of a thermistor string and a data recorder. Each thermistor string was 5m long and had eleven equally spaced thermistors. The data recorder logged the temperature of each thermistor every half-hour.

Data recovery was nearly 100% for the period April 1978 through May 1979. Some anomalous data was recorded due probably to weak batteries in the data-recording unit. For example, the south instrument recorded daily temperature variations of more than 40° F. These temperature changes are not plausible, because the plant discharge T is 20°F and during the time of these fluctuations the current recorder at this temperature station showed persistent current flow to the north.

Daily temperature variations of 2°F to 3 °F up to 20°F to 23°F were recorded and are plausible.

Temperature variation between late October to early May was small, generally less than 2 to 3° F within a 2 to 4-hour period. Between May and late September, the greatest temperature fluctuations occurred.

The pattern of temperature variation among the three stations at a given depth was very similar.

An analysis of the location and depth of the recorder and thermistor string indicates most of the large temperature changes were due to fluctuations in the thermocline elevation. Since all three recorders were well within the zone influenced by the thermal plume, the similarity of temperature change patterns among the stations demonstrates that natural energy inputs to the lake are far greater and cause greater temperature fluctuations than the thermal plume. Thus, the seasonal patterns of temperature change are unaffected by the thermal plume. Impacts of the thermal plume are isolated to the immediate plume discharge points. The position and persistence of the discharge cause localized temperatures and temperature change patterns that do not resemble natural lake conditions. Specifically the upper two meters of the lake within the thermal plume is the impact zone.

Thermal plume maps were produced by recording lake temperatures at one meter intervals from surface to bottom in the thermal plume vicinity and then plotting water temperature isotherms (Reference 3). A thermistor string was towed behind a boat (Figure 2.6-5) in a zigzag pattern through the plume while temperatures at each water depth, time and boat position were recorded on paper punch tape. This information was then used to generate thermal plumes at one meter INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 48 of 87

depth intervals. The plume dimensions in both areas at a given depth and total volume could be calculated within any selected T.

Two problems were encountered that confounded plume dimension estimates. One and a half to two hours were required to complete the field data collection necessary to map plumes. Two plumes a day could be mapped, weather permitting. On occasion, during the 1.5 to 2-hour plume survey, the intake water temperature would increase due to hypolimnion upwelling or plume recirculation. Variable lake currents could drive the plume in one direction and then reverse the direction or stop allowing the plume to spread in different directions. Thus, the plume mapped early in the two-hour period could be abnormally spread out due to the shift in lake current.

Most plumes mapped during two-unit operation were much less than the 570- acre limit allowed in the state issued NPDES Permit. Three plumes were mapped greater than the 570- acre limit.

On September 8, 1978, a 740 acre plume was mapped and on November 3, 1978, two plumes of 655 and 634 acres were mapped (Reference 3).

The plume mapped at 740 acres was 35% larger than the plume mapped that same morning.

Water intake temperatures, in situ lake temperature monitors and the thermistors on the plume mapping equipment indicate the lake temperature increased between the time the "ambient" temperature survey was made and the end of the plume mapping by 0.5°F to 2°F. If the ambient temperature was assumed to be 1°F higher, then the 4°F isotherm becomes the 3°F isotherm and plume drops from 740 acres to 113 acres. This is an excellent example of how a small change in the definition of ambient temperature makes a great difference in plume mapping results.

The two plumes mapped on November 3, 1978, were larger than the 570 acre limit at the 3° F isotherm due to a combination of several transient factors. The lake currents were variable and shifting from southerly to northerly flows. The plume appears to have been turned back upon its self causing an abnormally high plume recirculation since the Unit 1 and Unit 2 intake water temperatures were 2 to 3°F higher than the previous day and yet the in situ temperature records showed stable temperatures. So these plumes, 655 acres and 634 acres, were most probably the result of short duration transient conditions.

Twenty-nine plumes were mapped from August 23, 1978, through July 28, 1979. Three mapping surveys were made August 23 through September 8, 1978; November 1 through 7, 1978; and July 24 through 28, 1979. A summary of the plumes is presented in Table 2.6-3. The average plume area for all 29 maps was 290 acres. The smallest plume was 21 acres and the largest 740 acres (Reference 3).

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The thermal plume at Cook Nuclear Plant was shown to be dynamic and constantly altered by wind and lake currents. Several general observations about shape, size and location of the plume were made. Figure 2.6-6 shows the areas of Lake Michigan occupied by the thermal plume 3%

to 25%, 25% to 50%, 50% to 75% and 75% to 100% of the time. The plumes tend to drift to the northwest from the plant outfall structures. Finally, the thermal plume maps were all measured under calm lake conditions, conditions conducive to forming large plumes. Plumes will tend to be smaller during periods of winds and lake waves, which would themselves promote mixing as well as creating lake currents that also promote mixing of the plume with lake wa ter.

The thermal plume mapping, lake current monitoring and lake temperature monitoring studies were evaluated and compared to mathematical model predictions of thermal plume size and shapes under varying lake and meteorological conditions (ETA Engineering, 1980). With the exception of the three plumes that exceeded the 570- acre NPDES Permit limit, the surface area and volume of thermal plumes were over predicted by about two times the measured size of the plume at the 3°F isotherm. Under all but unusual wind and lake current conditions, i.e., light and shifting conditions, the Cook Nuclear Plant thermal plume will not exceed the 570 acre surface area limit.

ETA concluded, "The natural temperature changes represent a rate of change in the energy content of the water that far exceeds anything the Donald C. Cook Nuclear Plant could produce."

Meteorological studies were conducted in the vicinity of the Cook Nuclear Plant to monitor the effects on local climate resulting from the atmospheric heating and relativ e humidity increases caused by the once-through cooling system. This five-year study began in 1972 and ended in 1977. Figure 2.6-7 shows the location of the 12 meteorological stations used to gather air temperature, relative humidity and precipitation. Two of these stations also had equipment to measure wind speed and direction, visibility and thermal radiation (Reference 4).

This study concluded that

1. Lake Michigan has a large influence on coastal air temperatures and precipitation,

2. wind speed and direction were significantly altered by local terrain, and

3. the 1973 data from the Cook Nuclear Plant meteorological network was different from the 30- year average for spring and autumn precipitation patterns and for total precipitation in winter, summer and s pring (Reference 4).

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A statistical analysis of the data for air temperature showed that the Cook Nuclear Plant thermal plume would have to increase the air temperature above the background by at least 1°F to detect the change at the =0.05 level and 1.5°F at the =0.01 confidence level.

Although not a stated conclusion of the report, it is obvious and can be supported by calculations that the 16.8x109 Btu/hr heat rejection rate is insufficient to increase the air temperature by 1° F inland from the plant property (4).

Bathmetric studies were conducted at the Cook Nuclear Plant as required by the Technical Specifications, Appendix B of the NRC issued operating license. Results were reported in the semi-annual and annual environmental operating reports for the Donald C. Cook Nuclear Plant.

Bathymetry maps were produced by cruising Lake Michigan in a boat equipped with a depth transponder, radar positioning equipment and a real time data logger. The boat would zigzag in a systematic manner north and south in front of the plant and with each pass move farther offshore.

A similar east-west pattern was cruised moving farther south at each turn from the north end of the study zone. A baseline map was established in 1976 and diver surveys were used to monitor changes by visual observations for signs of bottom erosion near the intake and discharge structures. In the summer of 1979, diver observations confirmed bottom scour was occurring around the discharge structures. The erosion problems were corrected by pouring a concrete apron around these structures. In 1980, the boat surveys of lake bathymetry were resumed and continued through 1983. No significant bathymetric changes were documented after the problems discovered in 1979.

Biological Studies Periphyton was sampled in 1970 through 1972 (pre-operational sampling) and then from 1975 through 1981 (operational sampling). The pre-operational samples were collected using high-density styrofoam blocks moored to the bottom with enough line to allow the blocks to float about one meter below the water surface. In the operational studies measured areas of the plant water intake structures were scraped and the periphyton collected. Divers performed sample collections during the pre-operational and operational sampling. Pre-operational periphyton study results were reported in the Great Lakes Research Division, University of Michigan Special Report series and operational study results were reported in the annual environmental operating reports for 1978 through 1983. The results of the surveys showed that 45 taxa of periphyton were identified and the changes in species composition and periphyton standing crop (ash-free dry weight per unit area) was a result of periphyton community succession on new substrate such as the rip -rap artificial reef or the Cook Nuclear Plant water intake structure. The INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 51 of 87

natural habitat in Lake Michigan near Cook Nuclear Plant does not include solid objects for periphytic community development. The periphyton community is an artifact of the plant construction. The studies concluded plant operation has no impact on the periphyton community.

Phytoplankton was sampled from 1966 through 1982 in the Lake Michigan vicinity of the Cook Nuclear Plant. Sampling was conducted in the plant intake and discharge bays from January 1975 through May 1982. The open lake sampling for the Technical Specifications, Appendix B, began in 1973 and continued through May 1982. Lake samples were collected monthly from April through November each year with 36 to 39 stations sampled April, July and October and 9 to 13 stations sampled in May, June, August, September and November. All samples were whole water one-liter samples in either Niskin bottles or brown polyethylene bottles.

Plant entrainment samples were analyzed for cell counts in nine major algae taxanomic groups, chlorophylls, phaeophyton a and primary productivity by the C-14 method. A study was done to determine if the water in the intake forebay was heterogenious over the horizontal face of the trash racks and vertical water depth. The intake was determined to be heterogenious.

Cell counts by nine major groupings were analyzed for group numbers and total cell count were compared statistically between intake and discharge to determine if plant entrainmen t destroyed algae cells. No statistical differences were found. Chlorophyll a, b and c levels in intake and discharge samples were compared statistically and no difference found. Chlorophyll a to phaeophyton a ratios were compared statistically between the intake and the discharge. No differences were found.

Primary productivity rates were compared statistically between samples collected from the intake and discharge. Statistical differences were found. Primary productivity was reduced 16% to 76% in the discharge samples from rates measured in the intake samples. It was not determined if this reduction in primary productivity was permanent, because chlorophyll concentrations remained unchanged, which allows for possible complete recovery from the productivity reduction.

Lake samples were collected at the stations shown in Figure 2.6-8. Lake samples were analyzed for cell count by lowest practical taxa, which was usually species but occasionally was no lower than major group and for some taxa the variety was identified. Samples were analyzed for chlorophylls and for phaeophyton a. Impact analyses were done by comparing the pre-operational sample results with the operational results and comparing the near field results with the far field results within years. The parameters analyzed included species composition INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 52 of 87

similarity, species abundance, total cell count, diversity indicies, dominant species, species redundancy, chlorophyll content and chlorophyll a: phaeophyton a ratios.

The Lake Michigan phytoplankton community structure in the Cook Nuclear Plant vicinity was highly variable. However, the variability in sample results before operation were the same as variability during operation. Also, changes to the phytoplankton near the power plant paralleled the changes in sampling results from stations distant from the plant effluent. There were no significant differences in phytoplankton sampling results, therefore, it was concluded that the plant has no significant impact on Lake Michigan phytoplankton.

Zooplankton were collected from Lake Michigan from April 1969 through May 1982. From April 1969 through November 1972 samples were collected from 30 stations (Figure 2.6-9).

From April 1973 through May 1982, 30 stations were sampled in April, July and October and 14 stations were sampled in May, June, August, September and November. December through March were not sampled.

Lake sampling for zooplankton was conducted by towing vertically from the bottom to the surface a 0.5 m mouth diameter, No. 10 net (156-micron mesh) equipped with a flow meter.

Triplicate samples were collected at each station sampled. Zooplankton were identified (usually two species) and counted in the laboratory.

Entrainment samples were collected by pumping water from the intake and discharge bays through a No. 10 plankton net for 30 minutes (water volume was measured during the sampling).

Samples were collected monthly from February 1975 through May 1982. Samples were analyzed for live and dead animals and species identifications and counts were conducted.

Live/dead samples were held for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to determine the delayed mortality rate.

Lake sample results were analyzed by comparing species composition and abundance for pre-operational years with operational years. Also, samples collected in reference areas outside the thermal plume effect zone were compared with samples collected within the plume influenced zone. These analyses documented large changes in the zooplankton community from the pre-operational vs. operational data comparisons. There was no consistent pattern of abundances being higher (or lower) from the operational comparisons with the pre-operational data. Thus, there is no support for a conclusion that the Cook Nuclear Plant is having a significant adverse effect on the zooplankton community.

Entrainment samples were analyzed by comparing the survival of zooplankton collected from the plant intake base with survival of zooplankton collected from the discharge bay. An average of INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 53 of 87

10% of the total zooplankton in the intake bay samples were dead and an average of 12% were dead in the discharge bay samples. Dead zooplankton represented 4,480 kg of zooplankton dry weight per month. This biomass was probably distributed over a lake bottom area of 2.2 km² by the thermal plume. The 4,480 kg of dead zooplankton distributed over 2.2 km2 of lake bottom represents a detritus deposition rate of 67.5 mg/m²/day compared with a natural detritus deposition rate in Lake Michigan of 2,800 to 4,000 mg/m²/day. Therefore, the Cook Nuclear Plant increases detrital deposition rates of 1.7% to 2.4% over the natural depositional rate.

Neither the loss of 2% of the entrained zooplankton nor a detrital deposition rate of 67.5 mg/m²/day over and above the natural deposition rate would be a significant impact to the Lake Michigan ecosystem in the Cook Nuclear Plant vicinity was the conclusion expressed by the scientist conducting the zooplankton research.

Benthos studies of Lake Michigan in the Cook Nuclear Plant vicinity began in 1970 and continued through 1978. Samples were collected using a ponar grab sampler from stations established as shown in Figure 2.6-10. The sampling design underwent minor changes during the nine year study, but the majority of the study period included sampling 30 stations in April, July and October and 9 to 13 stations in May, June, August, September and November.

Depending upon the sampling design, between one and five replicates were collected at each station. Sediment samples were washed in a custom design sorter to retain all material that would not pass through a 0.500- mm mesh screen. The retained material was preserved and analyzed in the laboratory. Benthos were identified to species where practical and counted.

Benthos entrainment sampling was conducted from mid-1974 through 1978. Weekly samples were collected May through August and semi-monthly September through April. Water was pumped from the intake forebay and discharge bay for 24-hour periods, broken into 4-hour subsamples. The water was filtered through a 0.35-mm mesh plankton net.

Benthos population colonizing the rip-rap were sampled with artificial substrates. Sediment samples were visually classified using the Krumbein scale.

Benthos impingement sampling was conducted in conjunction with the fish impingement sampling. Screen wash baskets were sorted for fish and benthos daily in 1975 and every fourth day from 1976 through 1982 (benthos data through 1978 only were analyzed).

The lake sampling data were analyzed statistically for spatial and temporal population density differences. Five major groups were statistically analyzed - Pontoporeia hoyi (Amphipoda),

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(Oligochaeta) and Chironomidae (Diptera, Insecta) and total benthos. Plant effect was based on density estimates for each zoobenthic component obtained from lake sampling.

The only group to show any significant differences in population density were the Chironomidae.

Densities near the plant were higher after the plant began operation than before. It could not be determined if this was a positive or negative effect. While abundance of Chironomidae increased, the species composition shifted from chironomids generally associated with eutrophic conditions (Chironomus spp.) to species more typically associated with mesotrophic conditions (Saetheria tylus, Paracladopelma spp. and Robackio demeijerei). Power plant operation may have helped stimulate a naturally occurring mesotrophic trend in the inner region as indicated by similar, although less intense, changes in the outer region.

The researchers concluded that factor or factors of plant operations 1) resulted in an increased number of chironomids in the inner region disproportionate to that in the outer region, 2) aided in establishing conditions favoring a more homogeneous chironomid population structure in the inner region, and 3) aided in decreasing eutrophy in the inner region. Increases in the number of chironomids most likely reflect alterations of substrates, but increased (or at least more constant) food supply and temperature effects cannot be entirely ruled out. In general, changes in the benthos population structure attributable to the power plant were interpreted as essentially benign, but nevertheless real in terms of ecological changes.

Benthos entrainment samples were analyzed by first grouping the taxa that were entrained in sufficient number to conduct meaningful analyses. These groups were Pontoporeia hoyi, Gammarus spp., Hyalella azteca, Mysis relicta and Asellus spp. Entrainment impacts were evaluated by estimating the annual entrainment rate and then determining how much lake bottom will be required to produce the number or biomass of organisms.

Pontoporeia hoyi annual average entrainment was 1.97x108 individuals/yr or an average of 297 kg (285 kg/yr minimum and 315 kg/yr maximum). These numbers and weights were compared to the surface area in the central portion of the lake study area 0.48 km² that would be needed to produce 1.97x108 individuals or 1.07 to 3.99 km² to produce 285 to 315 kg of P. hoyi biomas s per year. Since no significant changes in P. hoyi numbers or biomass were evident from the lake surveys of benthos, then it is reasonable to conclude the entrainment losses had no adverse effect on P. hoyi.

Gammarus spp. like crayfish were present only because of the rip-rap habitat; therefore, it is difficult to assign impacts from plant entrainment to an organism that would not be present in the lake if not for the rip-rap apron around the intake.

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Hyalella azteca were only 0.1% of the entrainment total. The ecological significance of this entrainment estimate was not evaluated. This small portion of the entrained population impacted would not cause a significant change in the whole population of H. azteca.

Asellus spp. were 0.4% of the total benthos entrainment. The ecological significance of this loss was not evaluated. This small portion of the entrained benthos would not impact the Asellus spp.

population.

Mysis relicta entrainment averaged 1.11x108 individuals annually. This represents 0.59 km² of lake bottom near the intakes to produce the number of entrained organisms. Studies show M.

relicta are more abundant at the 30 to 50 m depth contours. Comparing 0.59 km² to the enormous profundal zone of Lake Michigan indicates M. relicta entrainment by Cook Nuclear Plant will not cause an ecologically significant impact.

Impingement of benthos was restricted to crayfish, nearly all of which were Orconectes propinquus. Impingement in 1975 was 16,151 and 7,625 in 1978 with a four-year total of 50,256 individuals or 326 kg of biomass. Impingement rates declined steadily during the four years of entrainment study. As with Gammarus spp., crayfish are present only as a result of the rip-rap reef around the intake. Therefore, ascribing an ecological significance to the entrainment losses appears illogical.

Rip-rap colonization by benthos was studied briefly as part of the overall ecological evaluation of Cook Nuclear Plant operation. Concrete artificial substrates were placed at Cook Nuclear Plant rip-rap and at Waugoshance Point. The benthos colonizing the Waugoshance Point artificial substrates were mostly filter feeders and at Cook Nuclear Plant mostly predators.

Artificial substrates at Cook Nuclear Plant were colonized by a species assemblage different from that collected in the Ponar grabs taken from surrounding unconsolidated substrates.

Comparison of the rip-rap benthos community with the Waugoshance Point community shows the similarity of the two communities. Thus, the community at the Cook Nuclear Plant is representative of benthos colonizing consolidated substrate in Lake Michigan.

Substrate analysis was done visually using the Krumbein scale. Most Ponar grabs less than 30 m were mostly sand. Pure gravels, silts and clays were uncommon except in highly localized, often transitory, patches.

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The following is the summary for the effects on benthos chapter of the final report on the Cook Nuclear Plant aquatic ecological studies (Reference 2):

1. Crayfish are the only macrozoobenthos in the vicinity of the Donald C. Cook Nuclear Plant large enough to be impinged on the traveling screens. Though a large number are impinged each year, the population probably is becoming stable.

The rip-rap provides the primary habitat.

2. The water intake entrains a wide variety of zoobenthos. The ecological effects of entrainment on lake populations of Pontoporeia hoyi and Mysis relicta are unknown but probably insignificant in comparison with lake populations present in the vicinity of the power plant.

3. Dynamics of the lake bottom zoobenthos populations in the vicinity of the Donald C. Cook Nuclear Plant show the general lake-wide trend toward mesotrophy.

Populations in the south region are slightly more mesotrophic due to greater accumulations of organic particulates while populations in the north tend toward oligotrophy, again due to structure of the substrate.

4. While populations of Chironomidae (and other major taxa) show general density increases over all years of the study in all regions, the central or inner region densities have increased more rapidly and toward a more homogeneous species composition. Reasons for increases in the inner region are unknown but may reflect altered current patters near the rip-rap or increased food supplies stimulated by the heated effluent. Most dramatic effects on the benthos are direct and indirect influences of the rip-rap.

5. A wide variety of benthic species have colonized the rip-rap (crayfish, amphipods, mayflies, caddisflies) which would not normally have been present on the open lake bottom.

6. The rip-rap may have altered current and sedimentation patterns in the inner region influencing the distribution and abundance of sediment-dwelling taxa, particularly the Chironomidae.

The fish studies in Lake Michigan near the Cook Nuclear Plant were conducted to 1) document the species of fish which inhabit the Cook Nuclear Plant area, and their distribution, spawning behavior, and nursery grounds, 2) determine the impact of the thermal plume on fish by comparing catch indices between the Cook Nuclear Plant and a reference area, 3) establish the INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 57 of 87

numbers of larval fish and fish eggs that were entrained at the Cook Nuclear Plant, 4) record the number of juvenile and adult fish impinged on Cook Nuclear Plant traveling screens, 5) describe the ecology of the major fish species for which there were adequate data, 6) integrate the various data sets from the phytoplankton, benthos, zooplankton and fish sections of the project to better understand their interactions in the nearshore zone of Lake Michigan, and (7) attempt to establish the significance of the entrainment and impingement losses through production forgone calculations.

Fish studies were conducted in the open lake and within the plant. Adult, juvenile, larvae and fish eggs were collected in both sampling programs. Open lake sampling was conducted monthly from April through November. Adult and juvenile fish were collected with gillnets, trawls and seines. Fish eggs and larvae, ichthyoplankton, were collected with 0.5 m conical plankton nets, 363-micron mesh, equipped with a mouth mounted flow meter. Figure 2.6-11 shows all open lake sampling stations.

Fish data were gathered from the open lake from 1973 through 1982. Adult and juvenile fish collected were identified, weighed, measured, sexed and observations noted for each fish on gonad development, stomach content, parasites and lamprey scars. Larvae and eggs were identified and counted (number/1000 m3).

Fish data were gathered so that pre-operational data sets could be compared with operational data (among years analyses) and plant influenced station data could be compared with reference station data (within year analyses). Temporal and spacial variations in species diversity and relative abundance were tested statistically using the analysis of variance procedure (ANOVA).

Fish samples collected in the power plant were all gathered in the screenhouse. Adult and juvenile fish impingement samples were collected by gathering all fish wash off from the traveling screens. These samples were gathered from 1975 through 1982. All fish were identified, weighed, measured and sexed. These observations were noted: gonad development, parasites, lamprey scars, and presence of food in the stomach. In 1975, all fish were analyzed from the 365, 24-hour samples. From 1976 through 1982, only fish collected from every fourth 24-hour period were fully analyzed. Fish gathered on the three intervening days were bulk weighed each day. Subsamples were analyzed when large collections of a species weremade.

Entrained ichthoplankton were pumped from three locations in the intake bay and one location in the discharge bay. Diaphram pumps were used to draw an average of 208 liters/ min from each location. The sample volume was passed through a 363-micron mesh net suspended in a 208-liter barrel equipped with a metered overflow pipe. Weekly or twice weekly samples were INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 58 of 87

pumped June through August and semi-monthly samples were pumped from September through May. Sampling began in 1975 and ended December 1982.

Ichthyoplankton samples were analyzed for species and number of entrained fish eggs and larvae.

Data analyses were conducted to estimate annually the number and weight of each species of fish impinged and estimate, by species, the number of eggs and larvae entrained. These data were used to calculate the fish flesh (biomass) that would have been produced had larvae, juveniles, and adults of alewife, rainbow smelt, spottail shiner and yellow perch not been impinged or entrained.

Lake studies of adult and juvenile fish were conducted from 1973 to 1982 by gillnetting, seining and trawling at the plant site and at a reference site, Warren Dunes. The primary purpose of this surveillance was to determine the distribution and abundance of fish at the two areas before and during plant operation. For fish species caught in sufficient numbers, statistical tests were employed to establish whether differences between area catches were significant. Data on other species were examined for consistency or trends in annual abundances in the two areas.

Over the 10 years, just over 1,100,000 fish of 59 species were caught (Table 2.6-4). Six of these species were abundant in the study areas. Alewife constituted 61% of the total catch over the 10 years. Spottail shiner contributed 21% of the total, rainbow smelt and yellow perch each contributed 7% and trout-perch and bloater each contributed just under 2%. All other species combined made up 1% of the total.

Fish species annual abundance or distributions that were statistically different from the Cook Nuclear Plant site compared with the Warren Dunes station established that that species was assumed to have been affected by plant operation. In general, four categories of effects in the Cook Nuclear Plant area were noted:

1. There was greater abundance during preoperational and operational years resulting from fish being attracted to the plant rip -rap. Diver observations helped to confirm this. There are no catch data before rip-rap placement, but because the topography and bottom sediments were similar at the Cook Nuclear Plant and Warren Dunes areas, it is probable that the preconstruction distributions of fish were similar.

2. There was greater abundance during operational years resulting from an attraction to the Cook Nuclear Plant rip-rap, structures and currents.

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3. There was lesser abundance during preoperational and operational years resulting from fish avoiding the alterations caused by construction, dredging and discharges.

4. There was lesser abundance during operational years resulting from either avoidance of the discharges and their effects or mortality caused by substantial impingement or entrainment.

Based upon lake survey catch data, three of the six most abundance species, alewife, bloater and rainbow smelt, were not affected by plant operation even though these species were abundant in the impingement catch also. These species were also the most abundant and mobile forage species in the lake. Immigrations from other areas could obscure any depletions caused by localized impacts.

In general, the abundance or distribution of 22 out of a total of 59 fish species was altered by the physical structure of the Cook Nuclear Plant or its operation. These alterations varied from a minor change in distribution (for example, the apparent attraction of a few redhorse suckers to the plant's discharges) to decreases in spottail shiner, trout-perch and yellow perch abundances at the plant site. The consequences of these changes to the lake's fish populations were not resolved and may be impossible to determine. For example, the plant's rip-rap attracted fish, thereby increasing their vulnerability to entrainment mortality, consequently diminishing abundance of some species. On the other hand, the rip-rap provided spawning substrate and food organisms which enhanced growth, reproduction and survival of some species.

Community structure may be only locally altered, with no important effect on the lake as a whole. In addition, the ability of the lake's fish populations to compensate for local abundance declines is unknown, and depends on the species, geographical area and population density.

Lake fish larvae data analyses did not show any statistically significant differences between preoperational years and operational years nor between Cook Nuclear Plant stations and reference stations at Warren Dunes State Park except for common carp larvae and rainbow smelt.

Common carp larvae were not collected during preoperational sampling and after operation began only two out of 23 samples containing common carp larvae were collected at Warren Dunes. Common carp appeared to be strongly attracted to Cook Nuclear Plant for use as a spawning area. Rainbow smelt were significantly more abundant at Cook Nuclear Plant than at Warren Dunes when the data for preoperational years 1974 and 1975, and operational years 1980-1982, were combined. This was due to unusually high catches of rainbow smelt larvae at INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 60 of 87

the Cook Nuclear Plant 6m and 9m depth stations in 1974. There were no significant differences when the 1974 data set was deleted from the analysis.

Adult and juvenile fish impingement annually at Cook Nuclear Plant were estimated to be from 53,190 in 1977 to 2,307,654 in 1980. Only one unit was operating from 1975 through most of 1978 when the second unit began operating.

Generally, the impingement rates are reflected in the change of water flow from one-unit to two-unit operation. About four times as many fish were impinged after two-unit operation began than when only one unit operated. Table 2.6-5 shows the annual estimated impingement rates.

Alewife impingement was higher than all other fish combined in all years except 1978 when alewives were only 38% of the impingement catch.

The percent contribution to total fish impingement over the period 1975 through 1982 was:

alewives (68%), spottail shiner (10%), yellow perch (9%), trout-perch (5%), rainbow smelt (4%),

slimy sculpin (2%) and others (2%). Figure 2.6-12 shows the annual percentages from 1975-1982.

There were only a few fish species showing any trends in the estimated number impinged annually. Trout-perch comprised 2.4% of the catch during the period 1975-1977 and dropped to 0.5% during the period 1980-1982. Slimy sculpin impingement followed a similar pattern. They were 4% of the impinged fish in 1975-1977 and 0.4% in 1980-1982.

Over 8 years, 61 species were impinged at the Cook Nuclear Plant. Nineteen species were impinged during only one or two years. Fourteen of these species were never collected in lake sampling and 12 species collected in lake sampling were never impinged.

Entrainment of fish eggs and larvae from 1975-1982 resulted in a total annual estimate of 750,000,000 fish larvae and 23 billion eggs. Annual estimates range from 33.5 million in 1977 to 167 million in 1982. Table 2.6-6 shows the annual estimate of fish eggs and larvae for the 13 species, four "undifferentiated genera" and "poor condition" and "unidentifiable" larvae entrained at Cook Nuclear Plant from 1975 through 1982.

Although the scientific literature strongly suggests otherwise, Alewife larvae were between 54%

and 92% of the annual estimated larvae entrainment and 74% of the annual average for the 8-year period. Spottail shiners were 9%, rainbow smelt 5%, yellow perch 2% and other 10% of the annual average fish larvae entrainment.

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Entrainment rates were strongly diel with night samples containing significantly more than day samples. May through August was the peak larvae density period with the maximum entrainment rate occurring in Juneor July each year.

the assumption was made at Cook Nuclear Plant that 100% of entrained larvae were killed.

Production forgone calculations from the entrainment and impingement data are estimates of the fish biomass that was not produced in Lake Michigan as a result of fish impingement and entrainment mortalities. Alewife production forgone estimates were 186,024 and 327,964 kg in 1975 and 1976, respectively. Spottail shiner production forgone was 6,011 and 1,736 kg in 1975 and 1976, respectively. Yellow perch production forgone was 1,647 and 1,812 kg in 1975 and 1976, respectively. Actual biomass of impinged fish of these three species in the respective years 1975 and 1976 were 5,203 and 3,003 kg for alewife, 88 and 232 kg for spottail shiner and 395 and 1,096 kg for yellow perch. For alewife and spottail shiner most of the production forgone comes from the entrainment of larvae of these species. Yellow perch larvae were far less abundant than for other species. Most of the production forgone results from the impingement of one-year old fish.

These production forgone estimates, while useful in characterizing fish losses beyond the mortality, present problems that make drawing conclusions about these calculations nearly impossible. A sensitivity analysis done on the production forgone calculations shows that the parameters that are the most poorly estimated, that is, mortality rates at the pro -larvae and post-larvae life states, have the greatest effect on the final estimate. The survival rate estimates used to derive the alewife production forgone were much higher than values reported in the literature.

In fact, actual data gathered during the lake studies showed actual survival rates for the Lake Michigan alewife population to be much lower than the survival rates used in the production forgone model. The result is the alewife production forgone estimates are severely biased upward from actual production forgone. Also, fish populations are dynamic. Reproductive success varies greatly from year-to-year due entirely to natural conditions; fish populations, while not demonstrated at the existing alewife population densities to actually occur, do exhibit density-dependent compensation for mortalities; and even after extensive study, the exact figure is elusive - it is generally believed fish populations can compensate for exploitation rates of about 20%. Lacking specific knowledge about compensatory mechanisms, difficulty with estimating correct age specific mortality rates and the difficulty of accoun ting for year-to-year variability, estimating production forgone becomes an interesting exercise, but not a useful tool.

The Cook Nuclear Plant did have impacts to the fish populations near the Cook Nuclear Plant.

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The ecological significance of these impacts was judged to be minor enough by the Michigan Water Resources Commission to approve a variance allowing Cook Nuclear Plant to discharge 16.8 x109 Btu/hr without specific temperature limits on the discharge and approve the plant intake structures as best available technology. In other words the ecological impact of impingement and entrainment did not justify modifying the plant to reduce the impact.

Sediment Chemistry Studies Sediment samples were collected from equally spaced intervals on a 10x22 km grid in Lake Michigan offshore from Cook Nuclear Plant. During 1973 and 1975, 158 surficial samples (0 to 3 cm depth) and seven cores were collected and analyzed each year for chemical and physical properties. Sediment particle size ranged from medium sand located generally near shore to silt located generally at lakeward stations. Core samples showed that coarser material was near the surface with finer material deeper in the sediments. Chemically, sediments tend to have higher concentrations of trace elements, heavy metals, nutrients, inorganic carbon, organic carbon and total carbon. Exceptions occurred frequently. High concentrations inshore of carbon, trace elements and heavy metals were generally associated with stream mouth deposits. No distribution patterns of any parameters were attributed to operation of the Cook Nuclear Plant.

Water Chemistry Studies Water chemistry samples were collected at a depth of one meter from 19 of the same grid points as used to collect sediment samples (10x22 km).Samples were collected every year from 1975 through 1982. In addition, six streams or drainages to Lake Michigan from the St. Joseph River south to and including Galien River were also sampled. The water chemistry associated with the thermal bar was studied.

Streams were consistently higher in nutrients and anions than the near shore lake water. Total phosphorus, dissolved orthophosphate, dissolved silica, nitrates, nitrites, chlorides and sulfates were higher in streams compared to near shore lake water. Chloride and sulfate were higher in streams, oxygen saturation was slightly higher, along with alkalinity and conductivity. pH was slightly lower in streams compared to lake water. All metals except molybdenum was from slightly to greatly higher in streams compared with lake water. Molybdenum concentrations were the same in streams as in the lake. Radiological monitoring of lake water is conducted annually and the results reported in the Cook Nuclear Plant annual radiological environmental operating report. No radionuclide concentrations have been found above natural background levels.

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Thermal bar study results were inconsistent. Because of the inter-relationship between nutrients, temperature and phytoplankton densities, differences in nutrient concentrations between inshore and offshore zones were inconsistent. All metals, both as particulate and dissolved metals, were in higher concentrations inshore vs. offshore except chromium and cobalt, which were higher offshore. However, only sodium was statistically higher in the inshore zone compared with offshore.

Water chemistry, chemical inputs and water mass movements were also studied in detail in an attempt to understand phytoplankton species composition and shifts during the study period from one major grouping to another and back again as the dominant group. The observations of this detailed analysis were summarized as follows:

"The observed variation in chemistry of the nearshore waters of southeastern Lake Michigan is complex and derived from a variety of sources. Observed areal variations in chemistry are controlled by the way in which stream and river inputs are incorporated within the nearshore water mass. The mixing of these inputs with nearshore waters gives rise to water masses, which trace their origin to stream, inputs. Other water masses are derived from the occurrence of the thermal bar in spring and upwelling of hypolimetic water during summer. Each water mass is chemically different from others, especially with respect to nutrients and temperature. These differences must be considered in any interpretation of nearshore phytoplankton distributions within any one sampling period or in month-to-month and year-to-year changes in phytoplankton assemblages" (Reference 2).

2.6.4 Ongoing Study Phase (1983 t o Present)

Asiatic clams (Corbicula fluminea ) and zebra mussels (Dreissena polymorpha ) have been introduced to the Cook Nuclear Plant area as well as other locations in Lake Michigan. An Asiatic clam shell was found at the plant in 1983 and zebra mussels were discovered in the plant intake forebay in 1990.

Asiatic clams have caused serious clogging problems in water intake systems in the southern United States over the past 30 years or so. The Nuclear Regulatory Commission issued a bulletin requiring nuclear plants to monitor for Asiatic clam infestation in 1982. Asiatic clams are heat tolerant and cold intolerant. Water temperatures at the plant will prevent this species from becoming a serious biofouling organism at Cook Nuclear Plant.

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water samples and plant raw water systems are carefully inspected during routine maintenance.

One live clam and about a dozen shell halves have been found in eight years of monitoring. No veligers have been collected.

Zebra mussels have been the cause of serious biofouling problems in Europe and Russia for many years (Reference 4). Water intakes for drinking water supplies and power plants have been clogged by zebra mussels in Lake Erie since they were first discovered in the St. Clair River in 1988. Zebra mussels are cold adapted animals and are considered a potentially serious biofouling problem at the Cook Nuclear Plant.

No Asiatic clams have been found since April 1991, when half-shells were found during a Clam-trol flush of the fire protection system. This system has been placed on Lake Township water since the Spring of 1993. No Asiatic clams or zebra mussels have been reported in the Fire Protection System since it has been placed on the Lake Township water system. There is a consensus that Asiatic Clams do not pose a threat to Cook Nuclear Plant as they are a warm water species. They are no longer a part of the monitoring program.

Biocides supplemented by mechanical cleaning and design changes including strainers, filters, screens, and chemical delivery systems, work to protect plant systems. A zebra mussel monitoring program utilizing side-stream and artificial substrate monitors, along with diver and heat exchanger inspections, is used to evaluate the effectiveness of chemical and physical control measures.

2.6.5 References for Se ction 2.6

1. Donald C. Cook Nuclear Plant, Supplement to Environmental Report, November 8, 1971

2. Monthly Bulletin of Lake Levels for the Great Lakes, March 1997, U.S. Army Corps of Engineers

3. Bluff Erosion, Recession Rates, and Volumetric Losses on the Lake Michigan Shore in Illinois, Richard C. Berg and Charles Collins, Illinois State Geological Survey, Environmental Geology Notes No. 76 July 1976.

4. Baker, D. L. 1993. Report on the 1992 Zebra Mussel Control Program. Letter from D.

L. Baker (I&M) to F. P. Morley (Michigan Department of Natural Resources).

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2.7 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM 2.7.1 Purpose of the Radiological Environmental Monitoring Program (REMP)

The purpose of the REMP is to establish baseline radiation and radioactivity concentrations in the environs prior to reactor operations, to monitor critical environmental exposure pathways, and to determine the radiological impact, if any, caused by the operation of the Donald C. Cook Nuclear Plant upon the local environment.

The first purpose of the REMP was completed prior to the initial operation of either of the two nuclear units at the Cook Nuclear Plant Site. The second and third purposes of the REMP are an on-going operation and as such various environmental media and exposure pathways are examined. A complete and technical representation of the REMP is set forth in the Donald C.

Cook Off-site Dose Calculation Manual (ODCM).

2.7.2 Preoperational Study The preoperational portion of the REMP was started 12 - 18 months before fuel was loaded into Unit 1. During this period, equipment was tested, sampling stations and sample media were determined, analytical procedures were tested, and some data was accumulated and examined for statistical variability. Modifications that were necessary to attain reliable and coherent data were made during this period.

2.7.3 Summary of Preoperational Radiological Environmental Monitoring Program There were several different types of environmental samples collected and analyzed during the preoperational sampling phase. Results from these samples are listed below.

The average monthly LiF thermoluminescent dosimeter (TLD) readings of August 1971 through December 1971, on-site, varied from 3.9 +/- 1.3 mrem to 11.7 +/- 0.8 mrem and off-site from 3.9

+/-1.2 mrem to 13.3 +/- 1.1 mrem.

Initial water samples were taken in Lake Michigan and at water treatment facilities located in Bridgman, St. Joseph, Benton Harbor, and New Buffalo. These showed tritium concentrations of 562 +/-36 pCi/l to 583 +/- 36 pCi/l. Gross beta at the above sampling stations showed 0.0 +/- 2.0 pCi/l to 6.8 +/- 1.0 pCi/l.

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The determination of gross beta in the on-site airborne particulate samples was 0.01 +/- 0.01 to 0.24 +/- 0.1 pCi/m3. The same values for off-site stations are 0.01 +/- 0.01 to 0.24 +/- 0.1 pCi/m3.

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2.8 PLANT DESIGN BASES DEPENDENT UPON SITE AND ENVIRONS CHARACTERISTICS

Information relating to the site and environs for the plant has been summarized in the preceding sections of this chapter. The several design features, which are dependent or affected by the site characteristics, are summarized below.

2.8.1 Unit Vent Gas Effluent A unit vent located on the outside of the reactor containment is used for the controlled, intermittent dispersal of decayed and diluted radioactive gases to the atmosphere.

2.8.2 Liquid Waste Effluent Liquid wastes, suitably decayed and diluted, are discharged to the lake intermittently through the circulating water discharge canal and to the turbine room absorption pond. Based upon circulating water dilution, the concentration of such wastes at the point of discharge from the station is in full compliance with 10 CFR 20. Substantial additional dilution and dispersion is provided by the lake thereby reducing concentrations to values far below permissible levels.

2.8.3 Wind Loading Design Plant building structures are capable of withstanding the effect of 90 mph winds. Although the possibility of a tornado occurring at the site during plant lifetime is remote, the plant can safely shutdown despite the effects of a tornado with a forward progression of 60 mph containing 300 mph winds coincident with an atmospheric pressure drop of 3.0 psi applied within 3 seconds.

2.8.4 Geology The geology of the region including the site indicates that the strata underlying the site are capable of supporting loads at least as high as those required for plant structures. The foundation design of all structures, and in particular those associated with plant safety, is based on the conditions existing at the site.

2.8.5 Hydrology Intermittent liquid effluents from the site do not affect ground water supplies in the adjacent area in excess of 10 CFR 20 due to local drainage patterns, release rates, and specific features of the sources of water supplies.

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2.8.6 Seismology The seismic design for structures important to safety is based on a horizontal ground acceleration of 0.10g and a vertical acceleration of two-thirds this value. This is the seismic criteria for the operating basis earthquake. In addition, the design is such that a safe shutdown can be made and the engineered safety features remain operable after the design basis earthquake of 0.20g horizontal ground acceleration and two-thirds this value acting vertically.

2.8.7 Limnology Plant grade and the design bases of features related to plant safety are established to consider the coincidence of the maximum seiche postulated for the site with the highest recorded lake level.

No consideration is given to the simultaneous occurrence of maximum high water level, maximum deep water waves and maximum seiche water levels because of the differing meteorological conditions required for the wave and seiche generation.

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2.9 PLANT DESIGN CRITERIA FOR STRUCTURES AND EQUIPMENT 2.9.1 Definition of Seismic Design Classification All equipment and structures are classified as Class I, Class II, or Class III as recommended in:

a. TID-7024, "Nuclear Reactors and Earthquakes" August, 1963 and

b. G. W. Housner, "Design of Nuclear Power Reactors Against Earthquakes,"

Proceedings of the Second World Conference on Earthquake Engineering Vol. I, Japan 1960, pg. 133, 134 and 137.

Class I Those structures and components including instruments and controls whose failure might cause or increase the severity of a loss-of-coolant accident or result in an uncontrolled release of excessive amounts of radioactivity. Also, those structures and components vital to safe shutdown and isolation of the reactor.

Class II Those structures and components which are important to reactor operation but not essential to safe shutdown and isolation of the reactor and whose failure could not result in the release of substantial amounts of radioactivity.

Class III Those structures and components which are not related to reactor operation or containment.

2.9.2 Classification of Structures and Equipment The classifications presented below are intended, by example, to convey the application of the seismic classification definitions.

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Item Class

Buildings and Structures Containment (including all penetrations and airlocks, the concrete I shell, and the interior structures)

Spent Fuel Pool I Control Room I Auxiliary Building Structure I Circulating water pump screen house structure(as required to make I water available to the essential service water pumps)

Turbine Room foundation I Remainder of Turbine Room structure III Buildings containing conventional facilities III

Ice Condenser I

Equipment, Piping and Supports I Reactor Control and Protection System, and Process Instrumentation (and Controls as required for Class I equipment and systems)

Reactor I Vessel and its supports, Fuel assemblies, RCC assemblies and drive mechanisms, Supporting and positioning members

Reactor Coolant System I Piping and valves (including safety & relief valves), Steam generators, Pressurizer, Reactor coolant pumps and motors, Reactor coolant system supports

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Item Class Emergency Core Cooling System I Accumulators, Residual heat removal system, Safety injection system, Centrifugal Charging system, Boron Injection Tank, Refueling Water Storage Tank

Containment Spray System I Spray additive tank

Chemical & Volume Control System Letdown and makeup components I Seal water system I Boric acid storage tanks and transfer pumps I Cleanup demineralizers and filters I Boric acid recovery equipment I

Condensate Storage Tank II

Auxiliary Feedwater System I

Essential Service Water System I Return Lines in Turbine Building III

Component Cooling System I

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Item Class

Ventilation Systems Engineered Safety Features Ventilation System I Control Room Ventilation System I Auxiliary Feedwater Pump Enclosure Ventilation System I Essential Service Water Pump Ventilation System I Emergency Power Ventilation Systems I Containment Ventilation System II & III Containment Air Recirculation/Hydrogen Skimmer System I Turbine Room Ventilation System III

Waste Disposal System Gas decay tanks I Liquid waste holdup tanks II Waste evaporator II Waste condensate tanks III Waste evaporator condensate pumps III

Non-Essential Service Water System II & III

Primary Water System Primary water storage tank II Primary water make-up pumps II Balance of System III INDIANA MICHIGAN POWER Revised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 73 of 87

Item Class

Control Air System Air compressor and receiver III

Fire Protection System III

Weld Pressurization System III

Spent Fuel Pool Cooling System Demineralizers and filters II Heat exchanger II Spent fuel pit pumps II

New Fuel Handling Equipment and Racks III

Spent Fuel Transfer Mechanisms II

Spent Fuel Storage Racks I

Refueling Cavity Manipulator Crane III

Containment Polar Crane I

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Item Class

New and Spent Fuel Crane I

Radiation Monitoring System III

2.9.3 Seismic Design Criteria for Seismic Class I and II Piping In addition to the loads imposed under normal operating conditions, the design of piping and piping supports requires that consideration also be given to abnormal loading conditions such as earthquakes and pipe ruptures.

Two types of seismic loadings are considered: Operational Basis Earthquake (OBE) and Design Basis Earthquake (DBE).

For the OBE loading condition, the nuclear steam supply system is designed to be capable of continued safe operation. Therefore, for this loading condition, structures and equipment needed for this purpose are required to operate within design limits. The seismic design for the DBE is intended to provide a margin in design that assures capability to shutdown and maintain the nuclear facility in a safe condition. In this case, it is necessary to ensure that required critical structures and components do not lose their capability to perform their safety function. This has come to be referred to as the "no-loss-of-function" criteria and the loading condition as the DBE.

The functional requirements of various components differ significantly. Some components must operate within the elastic region, since any significant deformation could result in loss of function. Active components such as rotating equipment, valves, motors etc. fall into this category. On the other hand, some components can experience significant permanent deformation without loss of function. Piping and vessels are examples of the latter where the principal requirement is that they retain their contents a nd allow fluid flow.

The normal as well as abnormal loads are considered singly and in combination (see Table 2.9-1 and notes thereto), and the allowable stress limits for each of the possible combinations are limited to those specified in Table 2.9 -2. Class I piping of 2 1/2 inch nominal diameter and greater, and Class I piping less than 2 1/2 inch nominal diameter with a normal operating temperature in excess of 250°F, are dynamically analyzed, using documented computer INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 75 of 87

programs. The computer programs employ multi-degree-of-freedom modal analysis methods which consider frequency, mode shape and modal participation factors in determining seismic response. Seismic inputs include the appropriate DBE spectra and/or the appropriate OBE spectra. When the OBE spectra are used exclusively for a particular system analysis, the seismic output piping stress and support reactions are multiplied by the conservative factor of 2 for determining DBE system adequacies and for designing support structures.

In the dynamic piping analyses, vertical seismic spectra equal to 2/3 of the pertinent building base horizontal spectra was computer input with the appropriate building floor horizontal seismic spectra. The effects of each seismic spectra input were computed independently and the various modal results were computer combined by the square root of the sum of the squares (SRSS) method. The effects of the vertical and a horizontal seismic run were then computer combined by the SRSS method. The larger resultant value of the vertical and horizontal seismic run [(Y +

X), or (Y + Z)] at each node was considered to be the critical load and/or stress.

Class I piping smaller than 21/2 inch nominal diameter with operating temperatures less than 250°F, may be qualified by using ei ther a simplified analysis (Alternate Analysis) method or a computer dynamic analysis. The Alternate Analysis method developed for the Cook Nuclear Plant considered gravity loads, seismic loads (based on floor acceleration response spectra) and internal pressure loads. The acceptance criteria were based on pipe stress and pipe displacement.

A set of instructions, guidelines, tables and graphs reflecting the above, were issued to establish acceptable spacing of supports.

Class II piping with operating temperatures less than 250°F may be qualified by using this Alternate Analysis method. Class II piping with operating temperatures greater than 250°F are qualified using the computer dynamic analysis method. The seismic inputs are taken from the appropriate OBE spectra.

Where a piping system consists of a combination of Class I and/or Class II, and/or Class III piping, the method of analysis is for the higher-class piping. The piping model may be structurally decoupled, to suit the higher class piping, at an anchor or at a point (or points) encompassing restraints in the 3 orthogonal directions.

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2.9.4 Seismic Design Criteria for Class I, Class II and Class III Structures Class I A dynamic analysis was performed using Response Spectrum and Modal Analysis Program, as discussed in Appendix F of the original FSAR, "Dynamic Analysis of the Containment Structure for Seismic Loading." Response spectra were generated from information obtained by a full seismological study of the site. The dynamic analysis of the Auxiliary Building superstructure supporting the Auxiliary Building east crane was modified to use spectra which were generated using Revision 1 of NRC Regulatory Guides 1.60 and 1.61. These changes were implemented as part of the Dry Cask Storage project and are further discussed in Section 2.9.5. Stress criteria are those of ACI 318-63 Ultimate Strength Design with the exception of the ice condenser wear slab.

The applicable code for the ice condenser wear slab is ACI 318-71.

To address projected increased loading on the spent fuel pool associated with the installation of high capacity racks in 1993, the structural reanalysis of the concrete under the racks was performed using ACI 318-89. This code was reviewed and accepted by the NRC in a license amendment submitted for the re-racking. ACI 318-89 was also used in the structural evaluation of the pool floor slab in the cask loading area in support of spent fuel cask loading operations.

Class II An analysis using the procedures of the Uniform Building Code (International Conference of Building Officials) was made. Standard working stresses are used.

Values of maximum ground acceleration are those used for Class I criteria. The factor applied to the seismic forces from which the values of shear, bending moments, etc. are computed, is taken as that for Zone 3 of the Uniform Building Code multiplied by the ratio of the maximum ground acceleration to a value of 0.30g. The minimum ratio used is one-fourth.

Class III An analysis using the procedures of the Uniform Building Code (International Conference of Building Officials) was made. Standard working stresses increased by 33 percent are used.

Zonal factors of the Uniform Building Code are used.

For All Structure Seismic Classifications A vertical component of earthquake acceleration of two-thirds the value of the horizontal component of earthquake is assumed to be acting simultaneously with the horizontal component.

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See Section 2.9.5 for a description of the horizontal and vertical acceleration used for analysis of the East Auxiliary Building Crane and Auxiliary Building superstructure supporting the crane.

When Seismic Class II or III structures, systems, and components (SSCs) are located within the interaction zone (where the SSCs are expected to fall, in the event that they fail) of a Seismic Class I SSC, then the subject Seismic Class II or III SSCs are designed and installed in such a way that there is no potential for the subject Seismic Class II or III SSCs to impair the functiona l capability of the Seismic Class I SSCs by adversely interacting with them during a Design Basis Earthquake (DBE).

Seismic design criteria for combined structures (i.e., structures having Class I and Class II elements, Class I and Class III elements or Class II and Class III elements) are as follows:

1. Equipment is supported by structural elements equal to or higher than the classification of the equipment.

2. Equipment is surrounded by structural elements equal to or higher than the classification of the equipment.

3. Structural elements are supported by, or framed to, elements equal to or higher than its own classification.

The following example illustrates the design criteria stated above.

The auxiliary feed pumps are Class I equipment but are housed in the turbine building which is essentially a Class III structure. In this case, the Class I equipment is supported b y the foundation slab which is designed to Class I criteria. The pumps are surrounded by local structural elements designed to Class I criteria which have been designed to withstand potentially adverse effects of lower class structures in the area.

The superstructure for the turbine room, heater bay and main steam pipe enclosure beyond the steam generator stop valve are Class III structures, which are designed for seismic loading in accordance with the seismic criteria of the Uniform Building Code. The maximum deflection for all conditions of loading were computed for these structures.

These deflections plus an allowance for erection and fabrication tolerances and an additional amount for clearance were designed into these structures to prevent rattling (hammering) effect.

The primary water and condensate tanks are functionally Seismic Class II structures located near Seismic Class I structures, namely, the refueling water storage tank and the containment. The INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 78 of 87

condensate and refueling water storage tanks have been seismically analyzed to insure their structural integrity during a seismic event. The primary water tank was analyzed seismically for the OBE. All three tanks are located in excess of 20 feet from the containment wall. The primary water storage tank is approximately 55 feet from the refueling water storage tank.

Analysis indicates that the primary water storage tank will not cause structural damage to the refueling water or condensate storage tanks in the unlikely event that it fails. The condensate storage tank, although not required to be a Seismic Class I structure, was designed as such to insure the structural integrity of the refueling water tank.

2.9.5 General Design Considerations for Building Structures Those structures considered are the auxiliary, containment, circulating water pump screen house and turbine buildings, and the steam generator stop valves and pipe enclosures outside the containment building.

Building structures were designed to withstand wind forces.

Class I building structures were evaluated with reference to tornado conditions to assure that there would be no loss of function.

The wind velocities and tornado model are discussed in Chapter 5 and Sub-Chapters 1.4 and 2.8.

Tornado loading was not considered coincident with earthquake loading. However, a 3 psi ambient pressure drop was considered coincident with tornado velocity pressures.

Pressure and suction forces together with internal pressure or suction was considered in accordance with the procedure in ASCE Paper No. 3269 "Wind Forces on Structures."

Torsional effects due to tornado loading were considered in evaluating Class I structures.

Maximum torsional loading was determined by using varying diameter tornado "funnels."

Reinforcing was placed so that minimum reinforcing cover provisions are as recommended by the Uniform Building Code and ACI Building Code.

1. 3 in. cover where concrete was deposited against the ground (bottom of slab).

2. 2 in. cover at all formed surfaces exposed to the ground or weather (all exterior surfaces of the structure).

3. 11/2 in. cover for beams and girders not exposed to the ground or the weather.

4. 1 in. cover for slabs and walls not exposed to the ground or weather.

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5. Concrete protection for reinforcement is in all cases at least equal to the diameter of the bars.

Building structures were designed in accordance with the seismic design criteria as stated in Section 2.9.4.

The effects of differential motion between the various buildings were considered. This was necessary both to provide adequate separation between the structures to prevent "banging together" of the structures during a seismic occurrence and to provide for this condition on interconnecting elements.

Both the horizontal and rotational motions of the containment structure due to earthquake were analyzed. A plot of displacement vs height was made.

The magnitude of maximum vertical motion due to the DBE was determined for the structures, considering each structure as a rigid body.

The maximum magnitude of differential motion was considered to be the absolute value of the peaks of motion between the independent structures, considering each motion to occur simultaneously with the others.

The effect of static differential settlement was considered additive to the dynamic effects where this resulted in a more severe condition.

A discussion of the design for the auxiliary and turbine building follows. The design of the containment building is discussed in Chapter 5.

Auxiliary Building The Auxiliary Building encloses the fuel storage areas (both new and used fuel), the fuel transfer canal, the containment equipment hatches access areas, control facilities and other equipment.

Seismic considerations for the Auxiliary building were based on the 10% and 20% Ground Response Curves as indicated in Figures 2.5-2 and 2.5-3. A dynamic analysis of the building was performed to determine the seismic stresses in Class I portions of the structure. Using a slab-spring model subjected to independent translational excitation in two perpendicular directions, the modal periods, the forces acting on the slabs, the slab displacement and the loads on major lateral load resisting elements were computed. Consideration was also given to the action of water in the spent fuel pool during a seismic occurrence.

The Auxiliary Building was designed using the method of the square root of the sum of the squares (SRSS) of the individual modal forces and stresses.

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The superstructure is a Class I structure consisting of a structural steel skeleton with exterior walls and roof of reinforced concrete.

The structural steel was designed in accordance with the "Specification for the Design, Fabrication and Erection of Structural Steel for Buildings," adopted April 17, 1963, by the American Institute of Steel Construction.

The roof of the structure is constructed of steel beams and girders supporting a poured concrete roof on steel ribbed decking. The roof varies in thickness, stepped from two feet to seven inches.

The thickest portion of the roof is directly over the spent fuel pool area.

The walls are of poured concrete supported, for their vertical load, on the concrete substructure and for their lateral forces by the structural steel columns and struts. The walls vary in thickness from two feet to six inches. The thickest area is the west wall adjacent to the fuel pool and the thinnest portion is at the east end of the structure.

The concrete walls and roof of the auxiliary building were designed to provide protection against potential missiles. The whole structure was designed to withstand the design basis tornado missiles and was also designed to protect the control room and fuel pool against a turbine missile. See Sub-Chapter 1.4 for a discussion on missile protection.

The tornado forces applied to the structure are as outlined in Chapter 5 with the exception that the diameter of the tornado was assumed to vary in the following manner:

a. The diameter is equal to the width of the structure.

b. The diameter is equal to the length of the structure.

c. The diameter is infinite in extent.

In the event of a tornado, the pressure within the structure will not differ from the outside by more than 1/2 psi in three seconds. This low differential is achieved by the installation of vents in the periphery of the roof, which will allow release of internal pressure. However, as an added conservatism, the building roof and walls have been designed to withstand 3/4 psi coincident with tornado wind forces. For forces resulting from tornado winds of 250 mph tangentially and a progression velocity of 50 mph, the auxiliary building steel will not experience stresses in excess of allowable as outlined in the 1963 American Institute of Steel Construction specifications. For tornado winds of 300 mph tangentially with a progression of 60 mph, coincident with internal pressures of 3/4 psi, steel will remain within yield and no permanent deformation will result.

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The auxiliary building, as a Class I structure, has been designed for seismic forces as described in this chapter. A dynamic analysis was made for the OBE and DBE. For the OBE, all stresses in the steel superstructure are within allowables as specified by th e 1963 code of the "American Institute of Steel Construction for Buildings." For the DBE, the superstructure steel stresses do not exceed yield and no permanent deformations will result.

For the 1988 Steam Generator Replacement Project, the following changes were made to the auxiliary building. An additional 150- ton single failure proof crane was installed and the existing 150- ton crane was upgraded to a single failure proof design. The building was reanalyzed for the following conditions:

a. The two cranes acting in tandem to move steam generator components during the replacement project.

b. The seismic forces, as described in this chapter, resulting from a single crane, or tandem cranes, with a 60-ton live load acting anywhere in the building.

For the OBE, all stresses in the steel superstructure are within Allowable as specified by the code of the "American Institute of Steel Construction for Buildings," adopted November 1, 1978. For the DBE, the superstructure steel stresses do not exceed yield and no permanent deformation will result.

For the Dry Cask Storage Project, the East Auxiliary Building Crane was uprated to a main hoist MCL of 145 tons for all operations. The crane, crane rails and the Auxiliary Building columns supporting the crane rails were reanalyzed utilizing the guidance provided in Regulatory Guide 1.60, Rev. 1 and Regulatory Guide 1.61, Rev. 1.

Specifically:

a. Horizontal Ground Response Spectra anchored to a 0.10g Zero Period Ground Acceleration (ZPGA) for the OBE and 0.20g ZPGA for the DBE.

b. Vertical Ground Response Spectrum anchored to 0.10g ZPGA for the OBE and 0.20g for the DBE.

c. Damping values for DBE and OBE per Regulatory Guide 1.61, Rev. 1.

For the OBE, all stresses in the steel superstructure of the Auxiliary Building are within Allowable, including the 1/3 increase in allowable stresses for seismic loads, as specified by the code of the "American Institute of Steel Construction for Buildings" adopted November 1, 1978, in accordance with the D.C. Cook allowable stress criteria. For the DBE, the stresses in the INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 82 of 87

Auxiliary Building superstructure steel (supporting the crane) do not exceed yield. As such, no permanent deformation will occur in the superstructure steel supporting the crane.

For the Dry Cask Storage project, the use of East and West Auxiliary Building cranes acting in tandem was not evaluated with the revised spectra based on the guidance provided in NRC Regulatory guides 1.60. As such, additional analysis will be required prior to the use of these two cranes in tandem.

Turbine Building A structure such as the turbine building, which consists of a Class I foundation and a superstructure, which is Class I in some areas and Class III in other areas, was designed as follows. The superstructure was designed in accordance with the criteria discussed in Section 2.9.4. The reactions at the base of the superstructure were used as input for the foundation design. The foundation was analyzed for lateral earthquake and a simultaneously acting vertical component, considering the effects on the foundations of the superstructure and any equipment supported directly on the foundation.

For seismic or tornado conditions, the mat was designed in accordance with the stress criteria of ACI Code 318-63 "Ultimate Strength Design." The load equations used were those of Sub-Section 5.2.2.3, with the elimination of the pressure and temperature items.

For normal load conditions, the mat was designed using Working Stress Design. Stresses and strains for normal loading were held to the limits of ACI Code 318-63 "Working Stress Design."

In the design of Class I structures by ACI Code 318-63 "Ultimate Strength Design" procedure, load reduction factors (Ø) used for the containment are discussed in Sub-Section 5.2.2.3.

However, for structures other than the containment structure and when considering seismic conditions, the load reduction factor for diagonal tension, bond and anchorage in concrete was reduced to 0.75.

Emergency Diesel Generator Ventilation Structures An analysis was conducted by PLG, Inc. to specifically address the effects of increased tornado wind loading on emergency diesel generator ventilation structures (exhaust silencers, combustion intakes, and room cooling intakes). These structures are located outdoors and are bounded by the containment, auxiliary, and switchgear buildings.

The results of this analysis indicate that the subject ventilation structures will experience tornado winds speeds of approximately 60 percent of the highest assumed incident tornado wind speeds.

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This reduction is due to the wind obstruction provided by the structures (buildings) in place around the ventilation structures.

2.9.6 Seismic Design Criteria for Equipment Typically, all safety-related equipment is designed to Seismic Class I criteria. However, not all Seismic Class I equipment is s afety-related. Examples of non-safety-related items which have been designed to Seismic Class I criteria are the new and spent fuel crane, the reactor vessel support cooling system and the steam generator blowdown piping.

Seismic Class I equipment design generally requires that normal plus DBE stresses do not exceed yield, and rotating or sliding equipment functions do not bind. The combination of earthquake plus normal stresses for the OBE condition shall not exceed normal allowable, as defined by applicable code. Refer to Table 2.9-1, and Notes thereto, for the definition of loading conditions. Restraints for both Class I mechanical and electrical equipment were generally designed to accept combined normal plus DBE loading without exceeding 0.9 of the yield stresses.

Class I equipment was designed for earthquake loads represented by the combination of appropriate horizontal and vertical floor responses simultaneously applied. The vertical response was equal to 2/3 of the horizontal response.

New response spectra, based on NRC Regulatory Guide 1.60, Rev. 1 and Regulatory Guide 1.61, Rev. 1, were utilized for a design analysis of the East Auxiliary Building Crane, the crane rails and the Auxiliary Building superstructure supporting the crane. These changes were implemented as part of the Dry Cask Storage Project and are further discussed in Section 2.9.5.

Depending on the relative structural complexity and relative rigidity of the equipment to be evaluated, one of the following methods of seismic qualification was performed:

1. For structurally complex equipment, with the exception of the spent fuel storage racks and the Dry Cask Storage unrestrained / freestanding stack-up, a dynamic multi-degree-of-freedom modal analysis which considered frequency, mode shape and modal participation factors in determining seismic response.

2. For structurally simple equipment, a dynamic single degree-of-freedom analysis, which considered fundamental frequency response of the equipment as, determined from the floor response spectrum.

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3. A simplified dynamic analysis, which utilized the peak of the floor response spectrum to determine seismic loading.

4. Testing of identical or similar components using approved procedures to simulate appropriate seismic loads.

5. For the spent fuel storage racks, a time history integration analysis of motion.

The specific analysis that utilized this methodology was reviewed and approved by the NRC (Reference 7).

6. The Dry Cask Storage unrestrained / freestanding stack-up was analyzed using time history integration analysis of motion.

2.9.6.1 Use of Earthquake Experience Data a s a Method for Assess ing Equipment Seismic Adequacy Revision 3 of the SQUG Generic Implementation Procedure (GIP-3) as modified and supplemented by the Nuclear Regulatory Commission Supplemental Safety Evaluation Report No. 2 (SSER No.2) and Report No.3 (SSER No.3) may be used as an alternative method for seismic qualification of mechanical and electrical equipment, electrical relays, and cable and conduit raceway systems and portions thereof (References 1 to 6). This alternative seismic qualification method is applicable to re -analysis or modification of existing items and to new or replacement items. This alternative method will not supercede specific commitments that were made for the seismic qualification of Regulatory Guide 1.97 equipment unless justified on a case specific basis.

2.9.6.2 References for Section 2.9.6.

1. Letter from Mr. John F. Stang of Nuclear Reactor Regulation to Mr. Robert Powers of Indiana Michigan Power dated February 3, 2000 on subject, Donald C.

Cook Nuclear Plant, Units 1 and 2 - Closure of USI A-46, Seismic Qualification of Equipment in Operating Plants, and review of licensees USI A -46 implementation program (TAC Nos. M69437 and M69438).

2. NRC (Brian Sheron) letter to SQUG (Neil Smith) dated June 19, 1998.

Clarification of the staffs position regarding incorporation of the GIP Method as a revision to the Plant Licensing Basis.

3. Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Plant Equipment, Revision 2, corrected 2/14/92 (GIP-2). Prepared by the Seismic INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 85 of 87

Qualification Utility Group (SQUG) and sent to the NRC by letter dated February 14, 1992.

4. Generic Implementation Procedure (GIP) for Seismic Verification of Nuclear Plant Equipment, Revision 3. Prepared by SQUG and sent to the NRC by letter dated May 16, 1997.

5. Implementation Guidelines for Seismic Qualification of New and Replacement Equipment / Parts (NARE) using Generic Implementation Procedure (GIP),

Revision 4, dated July 2000.

6. NRC letter to SQUG dated June 23, 1999. Review of Seismic Qualification Utility Groups Report on the use of the Generic Implementation Procedure for New and Replacement Equipment and Parts.

7. NRC SER N93004, Safety Evaluation By The Office of Nuclear Reactor Regulation Related To Amendment No. 169 To Facility Operating License No.

DPR-74 Indiana Michigan Power Company.

Qualification of Masonry Block Walls Masonry block walls have been evaluated for their potential impact on other safety-related or important to safety SSCs. Those walls, whose failures could result in adverse interactions with safety-related or important to safety SSCs have been designated as safety -related walls, and have been evaluated for normal and abnormal loading conditions. Abnormal loading considerations have included, as a minimum, seismic, HELB, and post-accident ventilation system operation as applicable for each wall. Where necessary, masonry block walls were modified to meet the applicable loading conditions. All safety-related masonry block walls are evaluated to ensure that the minimum acceptance criteria as given in Structural and Geotechnical Engineering Branch (SGEB) Criteria for Safety Related Masonry Wall Evaluation (NRC, July 1981) have been met. This SGEB criteria is contained within NRC Safety Evaluation Report N83096. This SER was issued following the NRC review of AEPs response to IE Bulletin 80- 11, Masonry Wall Design.

Wall 1-4033-W3 has been modified to utilize a sealed steel barrier in combination with a masonry block wall to perform the overall design function of the wall and to satisfy its design bases criteria. The sealed steel barrier has been evaluated for all normal and abnormal loading conditions in accordance with the "Specification for the Design, Fabrication and Erection of INDIANA MICHIGAN POWERRevised: 29.0 D. C. COOK NUCLEAR PLANT Chapter: 2 UPDATED FINAL SAFETY ANALYSIS REPORT Page: 86 of 87

Structural Steel for Buildings," adopted April 17, 1963, by the American Institute of Steel Construction. The masonry block wall is utilized as a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> rated fire barrier.

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2.10 C ONCLUSIONS

The previous sections have described the numerous site and environs studies which Indiana &

Michigan Electric Company has performed to qualify the site for nuclear plant operation.

The design, construction, and operation of the plant on this site meet the reactor siting criteria of 10 CFR Part 100 and the standards for protection against radiation of 10 CFR Part 20.

This conclusion is based on the following considerations:

a. The approximately 650- acre site provides minimum distance to the exclusion area of about 2000 feet.

b. There are no permanent residences on the site or within about 2160 feet of either containment structure.

c. The population of the area surrounding the site is low and only moderate growth is anticipated over the lifetime of the plant.

d. The use characteristics of the site environs are compatible with safe operation of the plant.

e. As tabulated in Chapter 14, the total radiation doses to an individual at the boundary of the exclusion area, or at the boundary of the "low population zone" under postulated hypothetical accidents, are well within the limits prescribed in 10 CFR 50.67.

f. Access to the site is readily available via road, rail and air. Numerous primary, secondary, and interstate roads provide connection with the surrounding area.

g. The meteorological, geological, hydrological, seismological, and limnological characteristics of the site and environs are suitable for operation of the plant.