ULNRC-05893, Callaway, Unit 1, Enclosure 41 to ULNRC-05893 - Rizzo (Rizzo Associates, Inc) 2008. Final Groundwater Model Report (Rev 1, Callaway Nuclear Power Plant, October)

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Callaway, Unit 1, Enclosure 41 to ULNRC-05893 - Rizzo (Rizzo Associates, Inc) 2008. Final Groundwater Model Report (Rev 1, Callaway Nuclear Power Plant, October)
ML12271A480
Person / Time
Site: Callaway Ameren icon.png
Issue date: 10/31/2008
From:
Paul C. Rizzo Associates
To:
Office of Nuclear Reactor Regulation, Ameren Missouri
References
ULNRC-05893
Download: ML12271A480 (71)
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Text

ENGINEERS&.

CONSULTANTS FINAL GROUNDWATER MODEL REPORT (REV.l) CALLAWAY NUCLEAR POWER PLANT PREPARED FOR:

ST. LOUIS, MISSOURI PAUL C. RIZZO ASSOCIATES, INC. EXPO MART, SUITE 270-E 105 MALL BoULEVARD MONROEVILLE, PENNSYLVANIA USA 15146 PROJECT No. 06-3624 OCTOBER 31, 2008 TABLE OF CONTENTS PAGE LIST OF TABLES .............................................................................................................

ii LIST OF FIGURES ..........................................................................................................

iii

1.0 INTRODUCTION

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1 1.1 OBJECTIVE

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1 1.2 REPORT ORGANIZATION

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2 1.3 SITE DESCRIPTION

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""." .... " ..... " .................

2 1.4 GEOLOGY"." ..... " ..... """ ..........

"" ... "" ..... """ .. " ... " ..............

"."" ... " .... " ...... 3 1.5 HYDROGEOLOGY

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4 2.0

SUMMARY

OF REVIEWED DATA .....................................................................

7 3.0 FIELD WORK .........................................................................................................

9 4.0 MODELING APPROACH ....................................................................................

1 0 4.1 CONCEPTUAL FLOW MODEL .......................................................................

10 4.1.1 Groundwater Flow Equations

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11 4.1.2 Code Selection

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11 4.2 MODEL DOMAIN .........................................................................................

12 4.3 BOUNDARY CONDITIONS

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12 4.4 HYDRAULIC HEAD DATA ............................................................................

14 4.5 HYDRAULIC CONDUCTIVITY

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14 5.0 MODEL CALIBRATION

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16 6.0 MODEL RESULTS ...............................................................................................

18 7.0

SUMMARY

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20

8.0 REFERENCES

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21 REFERENCES TABLES FIGURES Rl3 063624.04/08 Rev. I TABLE NO. TABLE 1 TABLE2 TABLE3 TABLE4 R13 063624.04/08 Rev. I LIST OF TABLES TITLE LIST OF UNIT 1 USEABLE MONITORING WELLS LOCATION AND ESTIMATED HYDRAULIC CONDUCTIVITIES OF TEST WELLS LOCATION AND AVERAGE WATER LEVEL MEASUREMENT OF UNIT 2 FSAR MONITORING WELLS SUMMARIES OF SITE HYDRAULIC CONDUCTIVITIES 11 FIGURE NO. FIGURE 1 FIGURE2 FIGURE 3 FIGURE4 FIGURE 5 FIGURE6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 FIGURE 16 FIGURE 17 FIGURE 18 FIGURE 19 FIGURE20 FIGURE21 FIGURE22 FIGURE23 FIGURE24 FIGURE25 FIGURE26 FIGURE 26 Rl3 063624.04/08 Rev. 1 LIST OF FIGURES TITLE SITE LOCATION SITE AREA GEOLOGIC MAP SITE AREA GEOLOGIC CROSS SECTION AQUIFER SYSTEMS OF NORTHERN, WESTERN, AND SOUTHERN MISSOURI LOCATION OF UNIT 1 & 2 MONITORING WELLS AND DISCHARGE LINE MODEL GRID ON OEM LAYER 1 ACTIVE AREAS LAYER 2 ACTIVE AREAS LAYER 3 ACTIVE AREAS LAYER 4 ACTIVE AREAS REFINED GRID SPACING AROUND UNIT 1 LAYER 1 BOUNDARY CONDITIONS LAYER 2 BOUNDARY CONDITIONS LAYER 3 BOUNDARY CONDITIONS LAYER 4 BOUNDARY CONDITIONS LAYER 1 HYDRAULIC CONDUCTIVITY LAYER 2 HYDRAULIC CONDUCTIVITY LAYER 3 HYDRAULIC CONDUCTIVITY LAYER 4 HYDRAULIC CONDUCTIVITY KTABLE CALIBRATION GRAPH LAYER 1 CALIBRATED GROUNDWATER ELEVATIONS LAYER 2 CALIBRATED GROUNDWATER ELEVATIONS LAYER 3 CALIBRATED GROUNDWATER ELEVATIONS LAYER 4 CALIBRATED GROUNDWATER ELEVATIONS MODEL GRID ON DEM POTENTIOMETRIC SURF ACE MAP GREYDON-CHERT (OBSERVED HEAD) lll FIGURE NO. FIGURE27 FIGURE28 FIGURE29 FIGURE 30 FIGURE 31 FIGURE 32 FIGURE 33 R13 063624.04/08 Rev. 1 LIST OF FIGURES (CONTINUED)

TITLE POTENTIOMETRIC SURFACE MAP MISSOURI RIVERALLUVIAL AQUIFER (OBSERVED HEAD) POTENTIOMETRIC SURF ACE MAP COTTER JEFFERSON CITY (OBSERVED HEAD) CROSS-SECTION OF GROUNDWATER FLOW FIELD UNIT 1 PARTICLE RELEASE UNIT 1 PARTICLE CROSS-SECTION UNIT 1 PARTICLES TO LAYER 4 PERIPHERY PARTICLE RELEASE iv FINAL GROUNDWATER MODEL REPORT FOR CALLAWAY UNIT 1 CALLAWAY NUCLEAR POWER PLANT

1.0 INTRODUCTION

In late 2006 and early 2007, Paul C. Rizzo Associates Inc. (RIZZO) engaged in communications with AmerenUE regarding the future groundwater modeling needs for Callaway Unit 1 and for post-operational of Callaway Unit 2. Thus, in May 2008, RIZZO was contracted to develop a Non-Safety Related Groundwater Model for Unit 1 Groundwater Protection Initiative (based on the following reference; A Guideline to Utilities-EPRI Report No. 1011730, "Groundwater Monitoring Guidance for Nuclear Power Plants" (EPRI, 2005), and the NEI Groundwater Protection Initiative (NEI, 2006) and NRC Information Notice 2006-13 (NRC, 2006), "Groundwater Contamination due to Undetected Leakage of Radioactive Material" (these references were supplied by AmerenUE)).

Previously, RIZZO developed a Groundwater Model to support evaluations that appear in the Callaway Unit 2 Final Safety Analysis Report (FSAR) Section 2.4.12 of the FSAR Final Submittal (AmerenUE, 2008). Since the development of the Model, data gaps have been identified.

The purpose of this study was to collect more data in the Callaway Unit 1 area, and to enhance the capacity of the previous model to accurately determine the groundwater flow patterns around the Unit 1 area. 1.1 OBJECTIVE The objective of this Report is to develop a groundwater model and to determine and interpret the hydrogeologic conditions of the area using this groundwater model related to site-specific groundwater flow patterns at four areas:

  • The immediate plant site area on top of the plateau -Unit 1;
  • The area of the extended site area including the hillsides and the immediate area at the bottom of the hill drained by Logan Creek and Mud Creek; R13 063624.04/08 Rev. I
  • The river bottom area south from the Katy Trail to the Missouri River, and west of the confluence of Logan Creek to approximately the Heavy Haul Road (County Road 459); and
  • The areas directly beneath and around the Power Block. 1.2 REPORT ORGANIZATION This Report is divided into seven major components:
  • Introduction;
  • Summary of Reviewed Data;
  • Field Work;
  • Modeling Approach;
  • Model Calibration;
  • Model Results;
  • Summary; and
  • References.

The Introduction Section provides a summary of background information on the study area. The Field Work Section provides information on new hydraulic testing and survey on Unit 1 monitoring wells. The Modeling Approach Section details the data used to construct model and modeling process. The Model Calibration Section discusses how the models were calibrated and the results of model calibration.

The Model Results Section presents selected output of the steady-state calibration. The Summary Section provides some general interpretation of the results. Lastly, the References Section provides a comprehensive list of site-specific and more general literature used in this Analysis.

1.3 SITE DESCRIPTION The Callaway NPP Site is located within Callaway County approximately 10 miles (16 km) southeast of Fulton, Missouri, and 80 miles (129 km) west of the St. Louis Metropolitan Area (Figure 1). The Missouri River flows by the Site in an easterly direction approximately 5 miles (8 km) south of the Site at its closest point. At this point, the elevations of 530 feet (162m) on the north and south sides of the river defme the Missouri River flood plain, which is about 2.4 miles (3.9 km) wide in this area. Rl3 063624.04/08 Rev. I 2 The Callaway NPP Site is located in an area of gently rolling upland, once part of an old glacial till plain. Erosion and downcutting of the Missouri River and its tributary streams have dissected the plain, leaving a nearly isolated plateau of approximately 8 square miles (21 sq km). The plateau has a maximum elevation of 858 feet (262m). The overall drop in elevation between the crest of the plateau and the Missouri River is about 350 feet (107m). Surface drainage to the east and northeast is to Logan Creek. Mud Creek is a major drainage way from the south and southwestern side of the Site. Auxvasse Creek, a major tributary to the Missouri River located about 2 miles (3.2 km) west of the Site area, intercepts surface drainage from the western and northern flanks of the plateau. Dominant existing land uses within 5 miles (8 km) of the Callaway NPP Site include Cool Season Grassland (25 percent), Forest (57 percent), and Cropland (14 percent).

The metropolitan centers closest to the Callaway NPP Site are Fulton, approximately 10 miles (16 km) to the west-northwest; Jefferson City, approximately 25 miles (40 km) to the west-southwest; and Columbia, approximately 30 miles (48 km) to the west-northwest.

[AmerenUE 2008, (FSAR 2.1.1.1)]

1.4 GEOLOGY Extensive and detailed work has been performed for Callaway Plant Unit 1 FSAR (AmerenUE, 2003) and Unit 2 FSAR (AmerenUE, 2008). Additionally borings for the foundation investigation, and geophysical acquisitions that includes S-Wave Reflection Survey as well as the results from deeper borings by the Missouri Department ofNatural Resources Cambrian correlation effort (the Cambrian sequence that follows beneath the Ordovician layers drilled in the Site area and Site vicinity (MODNR, 2007) examined and used to describe the geology of the area. [AmerenUE 2008, (FSAR 2.5)] The Callaway Plant Site area straddles the boundary between the Dissected Till Plains Physiographic Section to the north and the Ozark Plateaus Physiographic Province to the south (Figure 2). Most of the plateau area on the Site is covered by a fairly continuous layer of mottled reddish brown and gray silty clay (Modifier Loess) that varies in thickness from 3 to 15.5 feet (0.9 to 4.7 m) (AmerenUE, 2003), and from 4.5 to 22 feet (1.4 to 6.7 m) at Callaway Plant Unit 2 Site. The modified loess is underlain by a deposit of moderately plastic, gray, silty clay know as Accretion-Gley.

Glacial till layer consists of over-consolidated brown or mottled brown and gray silty clay containing some mixed sand and gravel and occasional lenses of silty or clayey Rl3 063624.04/08 Rev. 1 3 sand underlies the Accretion-Gley deposit in topographically high portions of the Site area. Beneath the glacial till is the Graydon Conglomerate that consists of cherty clay, sandstone, and sandy chert conglomerate that lies between the underlying Burlington Limestone and the overlying glacial deposits.

The sedimentary rock strata that occur immediately below the Graydon Chert Conglomerate and form the uppermost Lithi:fi.ed Formations throughout almost of the Site are called the Burlington and Bushberg Formations.

The Snyder Creek Formation underlies the Bushberg Sandstone throughout the Site area. The upper part is characteristically a light gray to light cream highly calcareous block shale. The uppermost part of the formation in some exposures area is a dense dark reddish limestone resembling the lower part of the Burlington Formation.

The oldest rocks penetrated by on-site borings are of Ordovician age. The only formation that was observed in borings was the Cotter-Jefferson City Formation; the Joachim and St. Peter Formations, as well as a zone of pre-St. Peter/post-Cotter-Jefferson City paleokarst rubble that separates the St. Peter Sandstone from the underlying Cotter-Jefferson City Dolomite as described in Callaway Plant Unit 1 FSAR. Figure* 3 shows the geologic cross sections of the Site area. Mapping of all Category I excavations for Callaway Plant Unit 1 by Dames and Moore ( 1980) and other geologic studies to determine the Site structural characteristics have revealed no major structures except for slumping into ancient karst features revealed within 5 miles (8 km) of the Site (Callaway Unit 2 FSAR 2.5.1.2).

1.5 HYDROGEOLOGY Several studies have investigated the hydrogeology of the Callaway plant areas. The most recent one is the Callaway Unit 2 Investigation.

The Field Investigation for Unit 2 was based on the local hydrogeological description and conceptual model developed for the Callaway Unit 1 FSAR (AmerenUE, 2003). The Site is located on a plateau at an approximate elevation of 840 to 850 feet (256 to 259 m) msl. The plateau serves as the headwater area for four sub-watersheds shown to extend from the 820 feet (250 m) mean sea level (msl) contour line toward the drainage boundaries.

Unnamed tributaries drain away from the plateau toward Logan Creek, Mud Creek, Cow Creek, and Auxvasse Creek, all of which ultimately drain to the Missouri River. No single drainage pattern accurately describes the creek watersheds.

Surface water moves radially from the topographic high toward the heads of tributaries that ring the plateau. The tributaries that ultimately drain to Mud Creek roughly follow a parallel drainage pattern; those to Logan Creek a trellis drainage pattern; and Rl3 063624.04/08 Rev. 1 4 those to Auxvasse Creek a dendritic drainage pattern. The elevation of the Missouri River in the vicinity of the Site is approximately 525 feet (160m) msl, which indicates that the topographic relief of the area is approximately 315 to 325 feet (96 to 99 m). A section of the important hydrogeologic units and their associated formations beneath the site either identified during site investigation or expected based on the regional hydrogeology and is shown on Figure 4. In the Callaway Unit 2 FSAR, across the plateau, the Graydon Chert Formation is considered to be the shallow aquifer. There are localized areas where the overlying material may be included in this aquifer, but in general it was found that saturated groundwater is confmed within the chert. During the Callaway Unit 2 Field Investigation, field personnel identified the chert as a moderate water-bearing unit, with the glacial till acting as the confming unit above the chert and the Burlington Limestone acting as the confming unit and top of the aquitard beneath the chert. The Graydon Chert lies unconformably atop the Burlington Limestone and unconformably below the glacial till, therefore, its elevation and thickness vary. Across the plateau, the depth of the Graydon Chert ranges from 15 to 39 feet (4.6-11.9 m) below ground surface (bgs) and averages approximately 27 feet (8.2 m) bgs. Its thickness ranges from 16 to 61 feet (4.9-18.6 m) and averages approximately 38 feet (11.6 m). Due to confmed groundwater conditions in the Graydon Chert aquifer, groundwater elevations measured in the monitoring wells rise above the top of the chert to within approximately 7 to 15 feet (2.1-4.6 m) of the ground surface in the central portion of the plateau. Overall, groundwater elevations did not vary much throughout the year, typically by less than 1 to 2 feet (0.3-0.6 m) across the central part of the plateau and several feet at the shallow wells around the perimeter of the plateau. Beneath the shallow aquifer there is a leaky, confining aquitard.

Based on the drilling of the monitoring wells across the plateau, the top of the aquitard begins with the top of the Burlington Limestone.

Based on the drilling of the deep monitoring wells MW-1D through MW-7D, the aquitard extends through the Bushberg Sandstone (only identified at the MW -4 and MW -5 well locations), Snyder Creek Formation (shale), Callaway Limestone, and upper portion of the Cotter-Jefferson City (CJC) Dolomitic Limestone.

The demarcation between the upper CJC (aquitard) and the lower CJC (aquifer) was identified during the drilling process when yielding fractures were encountered in the lower portion of the formation.

The depth to the top Rl3 063624.04/08 Rev. I 5 of the aquitard averages 68 feet bgs (20.7 m) across the plateau, and its thickness is approximately 290 feet (88 m) in the central portion of the plateau. Beneath the aquitard is the CJC aquifer. The depth to the CJC aquifer is approximately 3 50 feet bgs (107m) in the central portion of the plateau. Based on the well logs for the three AmerenUE industrial wells, the thickness of the CJC aquifer beneath the plateau is approximately 300 feet (92 m). Regionally, the CJC aquifer is considered to be a minor aquifer and represents the top of the Cambrian-Ordovician aquifer system, which consists of intervals of minor aquifers and major aquifers with intermittent aquitards to depths up to 2,000 feet (610 m) bgs. Groundwater levels for the deeper CJC wells beneath the plateau are also confined such that measured groundwater levels rise approximately 50 feet (15.2 m) above the top of the CJC aquifer to an approximate elevation of between 550 and 560 feet (168-171 m) msl. Although groundwater elevations appear to respond to seasonal changes in precipitation, they vary only by approximately 1 foot (0.3 m). From the Callaway Unit 1 Investigation, it was estimated that the well yield for the chert aquifer is less than 1 gallon per minute (gpm) (3.8 liters per minute (lpm)) and for the CJC aquifer is approximately 5 to 10 gpm (19-38lpm).

Drilling observations and pumping test results for the Callaway Unit 2 Investigation confirm these estimates. Two pumping tests were performed successfully in the CJC aquifer, and the relatively low estimates of storativity are consistent with mildly fractured bedrock aquifers where the small size of fractures and low degree of interconnectedness limits the amount of water in storage and the amount of water to potentially yield to a well. A step-drawdown test at a pumping well in the chert aquifer resulted in a dry well after a short period of time, which made the pumping test unviable.

Alluvial deposits along the Missouri River form an important stream-valley aquifer from the Iowa-Missouri state line to the junction of the Missouri and the Mississippi Rivers. The deposits partly fill an entrenched bedrock valley that ranges from about 2 to 10 miles (3 to 16 kilometers (km)) wide. Based on the regional understanding of the Missouri River alluvial aquifer, it was expected that groundwater elevations within the aquifer would mimic surface water elevations along the Missouri River and the lower reach of Auxvasse Creek (Callaway Unit 2 FSAR 2.4.1.2).

Rl3 063624.04/08 Rev. I 6 2.0

SUMMARY

OF REVIEWED DATA Based on the data and information received from AmerenUE, the following were reviewed:

  • Cross-sections, construction information for granulated fill under power block area;
  • Boring/well construction log of Unit 1 monitoring wells; and
  • 2006 -2008 quarterly water levels for existing Unit 1 wells. Review of the excavation and construction data revealed that the power block area was excavated to the chert conglomerate, and a plastic membrane as a protective cover for compacted Category I Structural Fill and Backfill, and Category I Cohesive Fill were used. In lieu of Category I Structure Fill and Category I Structure Backfill were mechanically compacted, the zones under the power block area will have different hydraulic properties compared to areas not excavated.

Hence, slug test are required for monitoring wells in both the excavated and excavated areas to be used in the groundwater model. Examination of boring/well construction logs of Unit 1 monitoring wells indicates that all monitor wells fall within the model domain. These wells are situated at Power Block area (MW936, MW937 A, MW937C, MW937D, MW937E, and MW937F), near Power Block Ultimate Heat Sink area (OW-l, OW-2, OW-3, OW-4 and OW-5), Land fill area (MW501 and MW502), and along the discharge lines (MWOOl, MW002, MW003, MW004, MW005,MW006,MW007,MW008,MW009,MW010,MW011,MW012MW013,MW014, MW015, MW016, M2, and M7). Based on the construction depth of screen intervals, the monitoring wells are grouped into 4 categories of hydrogeologic units used in the groundwater model:

  • Unconsolidated Glacial/modifier Loess materials:

OW-l, OW-2, OW-3, OW-4, OW-5, MW936, MW937A, MW937B, MW937C, MW937D, MW937E, MW937F;

  • Graydon Chert Aquifer: MWOOl, MW002, MW003, MW013, M2, M7, MW501, and MW502;
  • Cotter-Jefferson Aquifer: MW006, MW007, MW008, MW009, MWOlO, MWOll and MW012; and
  • Missouri River Alluvial Aquifer: MW004, MW005, MW014, MW015 andMW016.

Rl3 063624.04/08 Rev. 1 7 Monitoring wells F05 and F15 were excluded from the data used for groundwater model because adquate information on the screen interval depth was not available.

The data (boring/well construction log and quarterly water levels (2006 -2008) for existing Unit 1 wells) from AmerenUE were first entered into Microsoft Excel then transferred into dbase format for incorporation into Arc View. A total of 32 wells were combined into this data set. All of the wells were verified as having an accurate X, Y coordinates.

Attributes associated with these wells includes accurate elevation measurement, screen (top and bottom) elevation, well depth, water level and date the water level was taken. A detailed description of data fields for all of the delivered spatial data can be found in data CD that will be delivered to AmerenUE.

RI3 063624.04/08 Rev. I 8 3.0 FIELD WORK A well identification and inspection survey was performed in July 2008 by AmerenUE to ascertain which of the Unit 1 monitoring wells were useable in the Groundwater Monitoring Program and Modeling.

The following activities were performed on the wells: location (NAD 83) was resurveyed and depth and groundwater elevation from top of casing (NAVD 88) were measured.

The information was incorporated into RIZZO's existing into Geographic Information System (GIS) containing the Unit 2 wells to evaluate accuracy of the Unit 1 survey (Figure 5). Thirty-two (32) wells were considered to be useable (Table 1). Slug tests were performed by AmerenUE between July 22-25, 2008 on 11 monitor wells. The data from slug test was analyzed by RIZZO for the hydraulic conductivity (K). The 11 test wells were specifically selected to gain better understanding of the horizontal hydraulic conductivity (K) of the distinct geologic horizons under the Power Block, Ultimate Heat Sink (UHS) Pond, Landfill areas, and the areas along the periphery of the plateau. Table 2 summarizes the locations and the estimated hydraulic conductivities of aquifer material near each well tested. The well 502 test results were not used because information on boring radius of the well (well plus sand pack) was not available, but is required to calculate the hydraulic conductivity.

Rl3 063624.04/08 Rev. I 9 4.0 MODELING APPROACH The basic approach for this model was largely based on the a three-dimensional groundwater flow model developed by RIZZO to support evaluations that appear in the Callaway Unit 2 FSAR Section 2.4.1.2 of the Final Safety Analysis Report (FSAR) draft submittal (AmerenUE, 200&). The collection of good quality data was necessary to accomplish the objective.

Most of the data came from the previous work such as:

  • Boring logs and well constructions logs from both Callaway Unit 1 and Unit 2 investigations;
  • Hydraulic conductivity data derived from slug and pump tests from Unit 2 as well as this project;
  • Water levels taken from all Unit 2 wells and other wells considered reliable record wells for Unit 1;
  • Flow measurements for Auxvasse, Logan, and Mud Creeks, and Missouri River during Unit 2 Site Investigation;
  • Seepage estimates for drains around the periphery of the plateau and ponds during Unit 2 site investigation; and
  • Recharge estimates for precipitation of model domain from Unit 2. This Section describes the methods used to construct the numerical groundwater flow model for Unit 1 Groundwater Protection Initiative.

The process follows that described in the American Society for Testing and Materials (ASTM) Standard Guides D 5447-04, D 5474-93(ASTM, 1993a), D 5981-96 (ASTM, 2002), and D 5610-94 (ASTM, 2002), and also outlined in Anderson and Woessner (1992). 4.1 CONCEPTUAL FLOW MODEL The first step is to develop a conceptual model of the groundwater system of interest.

The purpose of building a model is to simplify the field problem and organize the associated field data so that the system can be analyzed more readily (Anderson and Woelssner, 1992). An effective conceptual model is one that is simple enough to be manageable, yet one that maintains enough complexity to achieve the goals of the model. Rl3 063624.04/08 Rev. l 10 4.1.1 Groundwater Flow Equations The groundwater flow equation for transient-state flow in a confmed aquifer system can be developed by combining the equation of conservation of fluid mass and Darcy's Law (4.1) where, K [LIT] is the hydraulic conductivity in the x, y, and z directions, h [L] is the hydraulic head, W is the volumetric flux per unit volume representing sources and/or sinks of water, Ss represents the specific storage [IlL], and tis time [T]. For unconfmed conditions, the specific storage is replaced by the specific yield, and the entire equation is multiplied by the saturated thickness (h). 4.1.2 Code Selection Visual MODFLOW Premium 4.2 computer program by Waterloo Hydrogeologic, Inc. (WHI) was used for the development and simulation of the three-dimensional groundwater flow model. WHI, a Schlumberger Company located in Waterloo, Ontario, Canada, has been developing groundwater software since 1989. WHI software is internationally recognized, accepted, and used by groundwater professionals around the world. The Visual MODFLOW Premium software package is a bundled group of software modules that were developed by other entities such as the United States Geological Survey (MODFLOW).

Multiple MODFLOW modules are used in the groundwater flow model. The Gradient Stabilized (WHS) module was selected to efficiently solve the matrix of fmite difference equations.

The Discretization (DIS) module contains information on the grid geometry and temporal discretization.

The Well (WEL) module is used to simulate pumping wells and assigned monitoring wells (observation wells). The Drain (DRN) module was used to simulate the drains on the plateau. The Constant Head (CHD) package is used to simulate specified head boundary conditions, and the General Head Boundary (GHB) was to simulate Ponds and Lakes. The River (RIV) package was used to simulate the surface water and groundwater interactions along the River and Creeks. The Recharge (RCH) module was used to simulate precipitation.

R13 063624.04/08 Rev. I 11 4.2 MODEL DOMAIN The model domain subdivided into [mite-difference cells. The horizontal cell size is a constant 300 feet by 300 feet throughout the model domain. The vertical grid spacing is variable, with 4 layers; 1) unconsolidated glaciaVmodifier Loess materials;

2) the Graydon Chert aquifer; 3) the aquitard, except in the area of the Missouri River floodplain where layer 3 represents the alluvial aquifer; and 4) the CJC aquifer. These layers were built from the bottom to the top. The bottom elevation of the CJC aquifer in the model is a constant 350 feet msl. The top of the CJC aquifer, top of the aquitard, and the top of the Graydon Chert aquifer were interpolated from discrete data identified during the drilling of the geotechnical borings and hydrogeological borings and monitoring wells during the Unit 1 and Unit 2 site investigations.

The ground surface was interpolated from the digital elevation file. The total number of finite-difference cells is 93744 (186 x 126 x 4) (Figure 6), although many cells are inactivated, as they are outside the model area. The active area varies for each model layer depending on the location of bedrock surface, but layer 4 has the largest active area (refer to Figure 7 through Figure 10). The model grid cells are specified as a combination of confmed and convertible layer types. The confined cells are used for layer 2 through 4, where the water table is not likely to intersect the top of the layer. The upper layer was simulated as convertible, and allowed to dry or inactivate when the simulated head decreased below the bottom of the cell. The wetting package was not implemented in this model due to numerical instabilities.

However, for an accurate numerical analysis at the Unit 1 areas, a horizontal cell size of 100 feet by 100 feet was used around Unit 1 (refer to Figure 11). 4.3 BOUNDARY CONDITIONS Boundary conditions are needed in order to solve the groundwater flow equation.

There are three types of boundary conditions:

  • Dirichlet

-Specified head,

  • Neumann-Specified flux, and
  • Cauchy-Head dependent.

Dirichlet boundary conditions are used when the heads are known at the model boundary. Neumann boundary conditions are applied as a positive or negative flux into the model domain. Cauchy boundaries are head-dependent, where a flux across a boundary is calculated based on R13 063624.04/08 Rev. I 12 the difference in head between the boimdary head and the first adjacent model cell multiple by the aquifer conductance (Harbaugh et al., 2000). The following boundary conditions applied to the Model (Figure 12 through 15):

  • River Boundaries (blue) were simulated in the model using linear interpolation of surface water elevations along the river segments.

At this boundary, each cell along the segment is assigned a surface water elevation in accordance with a linear interpolation between two end points. Conductance (seepage) between the rivers and the underlying aquifer was defmed 1500 sq ft/day (139.4 sq m/day) for Auxvasse, Logan, and Mud Creeks, and 2.25E6 sq ft/day (2.09E5 sq m/day) for the Missouri River (RIV package).

  • Drains (grey) were defmed along drainages from the top of the plateau down the hillsides to connections with the river boundaries.

These were also simulated using linear interpolation of approximated ground surface elevations along segments.

Like the river boundary condition, each cell along the segment is assigned an elevation in accordance with the linear interpolation between two endpoints.

Drains were also assigned around the periphery of the plateau in layers 1 and 2 to simulate seepage or evapotranspiration at the outcrop areas (DRN package).

  • General Head Boundaries (green) were assigned for the pond surface water elevations on top of the plateau using the GHB package. Conductance (seepage) between the rivers and ponds and the underlying aquifer was defmed as 90 sq ft/day (8.4 sq m/day) for the ponds, and 900 sq ft/day (83.6 sq m/day) for the Unit 2 excavation pond.
  • Constant Head Boundaries (red) were assigned along the edges of the model on the south side of the Missouri River and on the up-gradient edge of the alluvial aquifer to the east of Auxvasse Creek using the CHD package.
  • The Recharge (RCH) module is used to simulate precipitation.

Recharge was set to 2 inches per year for the Unit 1 area and the steep hillside areas, 3 inches per year for the remaining areas of the plateau, and 4 inches per year for the alluvial floodplain area. Recharge rates for relatively impermeable soils and steep hillsides will be relatively low as compared to the approximate 10 percent of normal precipitation that is estimated for the alluvial aquifer. Rl3 063624.04/08 Rev. I 13 4.4 HYDRAULIC HEAD DATA The spatial coverage of hydraulic head data within the Unit 1 area is limited. Likewise, there is a lack of deep wells to fully characterize the hydraulic head distribution within the Cotter Jefferson City (CJC), hence majority of the data for this model came from the Unit 2 Site Investigation.

To perform groundwater modeling tasks for the project, a suitable number of accurate well locations to monitor the head in various aquifer (Graydon Chert, Cotter-Jefferson, and Missouri River Alluvial) were needed. Hence RIZZO integrated Unit 1 wells and Unit 2 FSAR wells which fall within the model domain. A total of 31 wells from Unit 2 FSAR were considered reliable to use in the calibration of the groundwater model. Table 3 shows the list of Unit 2 FSAR monitoring wells. Static water levels from 63 wells (31 wells from Unit 2 and 32 wells from Unit 1) were used to calibrate the steady-state model (Figure 5). 4.5 HYDRAULIC CONDUCTIVITY There are a total of 36 hydraulic conductivity values available in the model domain; 26 were determined during the Unit 2 site investigation and 10 recently determined during the Unit 1 Groundwater Protection Initiative.

Hydraulic testing, including pumping and slug testing, were performed from 2007 to 2008. The hydraulic conductivity measurements are summarized in Table 4. Shelby-tube samples collected from the unconsolidated zone above or within the top of the Graydon Chert and from the vadose zone of the Missouri River alluvial aquifer were submitted for laboratory testing of moisture content, moist (wet) unit weight, specific gravity, total organic content, and vertical hydraulic conductivity.

The moisture content, wet unit weight and specific gravity were utilized to estimate the void ratio and porosity of the sample material.

Below are the summaries of the results:

  • Unconsolidated zone above and within top of Graydon Chert. The samples consisted of from 71.3 to 96.0 percent silt and clay; a few samples had approximately 20 percent fine sand. Moisture content ranges from 16 to 26 percent, organic content ranges from 1.3 to 2 percent, and estimated porosity ranges from 32 to 46 percent. Estimated vertical hydraulic conductivity ranges over four orders of magnitude from 1.2E-5 to 4.8E-3 ft/day ( 4.2E-9 to 1. 7E-6 em/sec).
  • Vadose zone of Missouri River alluvial aquifer. For three Shelby tube samples, the alluvial material consists of 80 to 90 percent silt and clay while for two Shelby tube samples at FMW-5 and FSB-13, the alluvial material consists of nearly 80 percent fme sand. This correlates to estimated vertical hydraulic conductivity values of 1.3E-4 to 2.5E-4 ftlday Rl3 063624.04/08 Rev. I 14 (4.6E-8 to 8.7E-8 em/sec) for the samples with high silt and clay content and 5.1E-1 to 6.0E-1 ftlday (1.8E-4 to 2.1E-4 em/sec) for the samples with high sand content. The estimated horizontal hydraulic conductivity of the Graydon Che t aquifer ranges over four orders of magnitude from 7.05E-3 to 9.02 ftlday (2.49E-6 to 3.18E-3 em/sec). The estimated horizontal hydraulic conductivity of the CJC aquifer ranges over two orders of magnitude from 1.57E-1 to 3.09 ftlday (5.54E-5 to 1.09E-3 em/sec). R13 063624.04/08 Rev. 1 15 5.0 MODEL CALIBRATION Visual MODFLOW provides a seamless interface to the Parameter Estimation (PEST-ASP) program, which is used to optimize a model calibration and assess the predictive capability of a model. Individual property parameters, such as hydraulic conductivity, storage, or recharge, are selected and a range of values is allowed for each parameter selected.

With the PEST option, the model was run many times, each parameter value was changed, the calibrated hydraulic head at each observation point was compared to the measured calibration target, and the overall error in the calibrated hydraulic heads was quantified.

The optimum value of each parameter was identified within the range specified through PEST method. At the end of each model run, the calibrated hydraulic heads were compared to the measured hydraulic heads and assessed where the calibration is strong versus weak. The parameter optimization process is tedious as many runs with PEST are required to assess different areas and layers of the model. In this model, the estimated values of hydraulic conductivity from slug tests were imported at the different well locations at the well screen midpoint.

Again, these values were associated with a specific layer in the model. These values were interpolated across the model domain for each layer and zones of hydraulic conductivity were subsequently defined from this interpolation.

For horizontal hydraulic conductivity, Kx =Ky. Initial values ofKz were defmed by the mean of Shelby tube sample values. These zones of hydraulic conductivity were the starting values for the model calibration process. Through the calibration process, these zones and their values were changed to create a flow balance in the model layers such that estimates of hydraulic head were similar to actual measured values (i.e., calibration targets).

The calibrated hydraulic conductivity fields are shown on Figure 16 through Figure 20. The Site Investigation monitoring wells were inserted into the model with survey coordinates.

The monitoring elevation was set to the middle of the well screen and this screen elevation is associated with a specific layer in the model. The calibration target value at each well was estimated as the average value of those measured between March 2006 and January 2008. A total of 63 hydraulic head measurements were used to calibrate the simulated and observed heads. The model calibration yielded an acceptable agreement between simulated and observed hydraulic head values. The absolute model error, which is taken as the sum of the absolute difference between simulated and observed head values divided by the total number of head RI3 063624.04/08 Rev. 1 16 measurements, was 3.65 feet. Another calibration parameter, the normalized absolute error, was 1.48 percent. Generally, models are considered acceptable if the normalized absolute error is below 5 percent (Figure 21). Rl3 063624.04/08 Rev. 1 17 6.0 MODEL RESULTS The hydraulic heads, as simulated from the model for the four layers, are shown on Figure 22 through Figure 25. Generally, slightly higher head are simulated in layer 1 except the power block areas, which show slightly low simulated head. The higher head in layer 1 are associated with partially saturated to saturation of the glacial and the post-glacial material above the Graydon Chert, while the post-construction back-fill around the power block is responsible for the lower simulated head. Figure 26 through Figure 28 shows the potentiometric surface contour (average hydraulic head between March 2006 and January 2008). In layer 2, calibrated hydraulic heads match the observed heads very closely. Potentiometric surface contours are similar to those presented on Figure 23, except, that the model contours extend the measured data points at monitoring well locations to the drains along the layer boundaries.

The model predicted potentiometric surface contours in layer 3 around the flood plain are similar to those presented on Figure 27. Even though layer 3 was designated as Aquitard, it should be noted that along the Auxvasse Creek and Missouri River stream boundaries, alluvium replaces the aquitard and the hydraulic conductivity of the alluvium was not allowed to vary during the model calibration activities.

In layer 4, the model predicted potentiometric surface contours are similar to those presented on Figure 28. Once the Model was calibrated, advective particle paths were calculated to visualize the groundwater flow directions using the steady-state model. MODP ATH module was utilized to evaluate groundwater flow pathways from Unit 1 power block areas. Figure 29 shows that for a groundwater flow that originates in the power block area, the relationship between (relative magnitude of) the horizontal and vertical velocities determine its flow path as it travels across the plateau, leaves the Graydon Chert aquifer, travels through the aquitard and underlying Jefferson City aquifer until it reaches a point of discharge to a surface water drainage or stream. A circle of particles around the Unitl area were released in layer 2 (Graydon Chert aquifer) and allowed to travel for 20,000 days. The resulting travel paths are shown on Figure 30. The particles initially travel radially and downward through the chert, but as the particles leave the chert they move downward and southly through the aquitard.

The particles are also allowed to travel for 200,000 days and the flow paths are shown in cross-section and in plan-view on Figures 31 and 32, respectively.

The flow paths on Figure 32 are a plan-view projection of the R13 063624.04/08 Rev. 1 18 three-dimensional flow path, and the particles actually reach layer 4; this Figure should not be interpreted as groundwater flowing at or near the ground surface rather the direction of groundwater flow within the Cotter Jefferson City (CJC). Finally, a circle of particles are released around the periphery of the plateau in Layer 2, and the results (Figure 33) shows that groundwater that enters the Graydon Chert aquifer around the periphery of the plateau is influenced by the drainages.

It was observed that groundwater in this area still flows with a downward component and only some discharge to the drainages while some continue to move downward beneath the drainages and will potentially discharge at drainage locations further down the hillside.

R13 063624.04/08 Rev. 1 19 7.0

SUMMARY

The purpose of this Report is to develop a Groundwater Flow Model to aid in understanding the pathways of the groundwater flow that originates from the Unit 1 areas, and to evaluate potential contaminant migration pathways for future contaminant fate and transport models. The groundwater model constructed provides a relatively accurate tool to quickly assess long-term changes to the aquifer system by including temporal variation in recharge (around plateau and flood plain), the drainage (on plateau), the streams (Auxvasse, Mud and Logan), and the Missouri River flow. This Model can now be used by AmerenUE as a useful tool to further assess the impact of present and future potential pathways of groundwater flow. The major conclusions that can be drawn from this Report include:

  • A groundwater particle starting at the top of the Graydon Chert aquifer in the power block area will travel horizontally outward and vertically downward according to the estimated groundwater flow velocities and enter the aquitard.
  • Once the groundwater particle moves into the aquitard, they would experience only downward and vertical flow until the CJC aquifer is reached.
  • The groundwater particle remains in CJC aquifer as it flows toward the potential discharge location along-Auxvasse Creek or along Mud Creek.
  • Also the groundwater particle that originates around the periphery of the plateau or along the drainages that runs from the periphery of the plateau will still flow with a downward component; only some discharge to the drainages while some continue to move downward beneath the drainages and will potentially discharge at drainage locations further down the hillside.

R13 063624.04/08 Rev. 1 20

8.0 REFERENCES

American Society for Testing and Materials (ASTM), 1993a. Ground-Water Flow Model to a Site-Specific Problem, ASTM D 5447-93, Philadelphia, PA. American Society for Testing and Materials (ASTM), 1994b, Standard Guide for Defining Initial Conditions in Ground-Water Flow Modeling, ASTM D 5610-94, Philadelphia, PA. American Society for Testing and Materials (ASTM), 1996, Standard Guide for Calibrating a Ground-Water Flow Model Application, ASTM D 5981-96, Philadelphia, PA. AmerenUE, 2008, Callaway Nuclear Power Plant Unit 2 Draft Final Safety Analysis Report 2008. Anderson, M.P., and W.W. Woessner, 1992, Applied Groundwater Modeling:

Simulation of Flow and Advective Transport, Academic Press, San Diego, California.

Electric Power Research Institute (EPRI), 2005, "Groundwater Monitoring Guidance for Nuclear Power Plants." Harbaugh, A.W., E.R. Banta, M.C. Hill, and M.G. McDonald, 2000, MODFLOW-2000, The U.S. Geological Survey Modular Ground-Water Model-User Guide to Modularization Concepts and the Ground-Water Flow Process, U.S. Geological Survey Open-File Report00-92, Reston, Virginia.

Nuclear Energy Industry (NEI), 2006, "Nuclear Energy Industry Unveils New Policy To Manage Inadvertent Radiological Releases", Nuclear Energy Institute News Release, May 9, 2006. Nuclear Regulatory Commission (NRC), 2006, NRC Regulatory Issue Summary 2006-13, "Information on the Changes Made to the Reactor Oversight Process to More Fully Address Safety Culture", Nuclear Regulatory Commission, Office of Enforcement, July 31, 2006. Nuclear Regulatory Commission (NRC), 2007, "Postulated Radioactive Releases due to Containing Tank Failures, Branch Technical Position 11-6, NUREG-0800, Standard Review Plan," Nuclear Regulatory Commission, March 2007. UniStar, 2007, "Calvert Cliffs Nuclear Power Plant Unit 3 Final Safety Analysis Report," UniStar Nuclear Development, LLC. Waterloo Hydrogeologic, Inc. (WHI), 2006, Visual MODFLOW Premium 4.2, Waterloo Hydrogeologic, Inc., Schlumberger Water Services. Rl3 063624.04/08 Rev. I 21 TABLES TABLE 1 LIST OF UNIT 1 USEABLE MONITORING WELLS NAVD88 AVERAGE WELL UTME-NAD83 UTMN-NAD83 ELEVATION OF GROUNDWATER NORTHING (FT) EASTING (FT) CENTER OF ELEVATION SCREEN (FT) (FT MSL) (FT) MWOOl 1068639.785 1844591.481 819.019 829.044 MW002 1065323.863 1844512.707 813.866 818.746 MW003 1064780.635 1847240.943 814.621 830.187 MW004 1048241.82 1850566.251 510.986 513.462 MW005 1048478.619 1852327.073 511.970 510.829 MW006 1051490.434 1848058.08 517.898 525.032 MW007 1051457.886 1847668.138 524.657 526.696 MW008 1051143.178 1847916.098 519.019 521.392 MW009 1050937.134 1847663.175 521.724 522.353 MWOlO 1051190.923 1847654.819 520.785 525.530 MW011 1053254.46 1846273.765 556.208 553.501 MW012 1051496.629 1847989.841 433.984 524.938 MW013 1063194.865 1846819.986 817.562 818.119 MW014 1047702.993 1848449.195 499.924 509.194 MW015 1047338.257 1852001.673 499.696 509.629 MW016 1046624.393 1857060.846 489.631 505.201 MW501 1065915.302 1847763.011 801.310 823.475 MW502 1068157.02 1847501.148 798.879 825.515 MW-936 1067072.771 1845567.683 821.817 829.617 MW-937A 1067314.054 1845915.749 824.771 830.977 MW-937B 1066810.963 1845242.275 821.967 831.996 MW-937C 1067169.503 1845788.3 89 817.128 830.286 MW-937D 1067009.024 1845928.659 819.063 830.575 MW-937E 1066690.45 1845650.623 820.153 832.181 MW-937F 10667 41.124 1845145.06 823.857 831.912 M2 1069044.579 1843572.398 743.108 792.368 M7 1063063.308 1845949.375 720.070 706.895 OWl 1066186.76 1845549.167 814.655 834.855 OW2 1066391.704 1845765.443 815.774 834.104 OW3 1066031.665 1845901.718 819.944 834.137 OW4 1066191.637 1846070.13 818.116 832.859 OW5 1065894.242 1845756.706 821.256 834.786 R13 063624.04/08 Rev. 0 TABLE2 LOCATION AND ESTIMATED HYDRAULIC CONDUCTIVITIES OF TEST WELLS NAME TYPE OF AQUIFER NORTHING EASTING K(FT/DAY)

MW937F GRAYDON CHERT 1066741.124 1845145.060 3.65E-01 MW937C GRAYDON CHERT 1067169.503 1845788.339 1.00E+OO OW-l GRAYDON CHERT 1066186.760 1845549.167 9.94E-01 OW-2 GRAYDON CHERT 1066391.704 1845765.443 1.12E+OO OW-3 GRAYDON CHERT 1066031.665 1845901.718 3.93E-01 MW008 COTTER-JEFFERSON 1051143.178 1847916.098 1.15E-01 MWOll COTTER-JEFFERSON 1053254.460 1846273.765 7.78E-01 MW013 COTTER-JEFFERSON 1063194.865 1846819.986 2.03E+OO MW015 COTTER-JEFFERSON 1047338.257 1852001.673 8.21E-01 M7 COTTER-JEFFERSON 1063063.308 1845949.375 1.46E-02 R13 063624.04/08 Rev. I TABLE3 LOCATION AND AVERAGE WATER LEVEL MEASUREMENT OF UNIT 2 FSAR MONITORING WELLS AVERAGE LOCATION NORTHING EASTING GROUNDWATER ELEVATION (FT MSI) Gra' don Chert Aquifer PW-1 1067801.65 1845747.19 829.77 MW-2S 1076444.82 1846189.87 770.36 MW-3S 1068236.86 1850889.85 805.99 MW-5S 1066063.58 1839748.89 794.02 MW-6S 1071137.82 1840344.23 814.46 MW-8 1069314.02 1845853.56 828.96 MW-9 1067031.11 1846943.76 827.45 MW-10 1065231.21 1845930.93 823.70 MW-12 1068338.49 1843101.33 826.97 Cotter-Jefferson Aquifer MW-1D 1067745.62 1845729.23 553.26 MW-2D 1076453.63 1846204.02 552.88 MW-3D 1068262.36 1850885.26 553.20 MW-4D 1058085.89 1843973.82 553.23 MW-5D 1066050.55 1839738.72 555.88 MW-6D 1071109.51 1840342.79 553.34 MW-13 1087151.31 1837276.03 544.19 MW-14 1073323.07 1826004.31 523.04 MW-15 1046106.94 1833429.17 516.76 MW-16 1052711.25 1839372.03 530.60 MW-17 1049043.77 1845199.81 528.65 PW-2 1065502.11 1828469.87 517.68 PW-3 1061781.07 1855490.04 560.89 Missouri River Aulluvial Aquifer FMW-1S 1038995.53 1837956.06 507.69 FMW-5 1047388.10 1851772.50 508.73 FMW-6 1040481.32 1851066.54 505.59 FMW-7 1039841.12 1849706.88 505.84 FMW-8 1039529.50 1848383.31 505.62 FMW-9 1039620.36 1846762.66 506.53 FMW-10 1039680.35 1845265.75 506.87 FMW-11 1039136.45 1839487.41 507.40 FMW-12 1045810.79 1857168.19 504.25 Rl3 063624.04/08 Rev. I TABLE4 SUMMARIES OF SITE HYDRAULIC CONDUCTIVITIES NAME NORTHING EASTING TEST TYPE K(FT/DAY)

Graydon Chert Aquifer PW-1 1067801.652 1845747.186 SLUG 7.06E-02 MW-2S 1076444.815 1846189.867 SLUG 1.64E-Ol MW-3S 1068236.859 1850889.852 SLUG 9.02E+OO MW-5S 1066063,580 1839748.889 SLUG 5.78E-02 MW-6S 1071137.817 1840344.234 SLUG 7.05E-03 MW937F* 1066741.124 1845145.060 SLUG 3.65E-01 MW937C* 1067169.503 1845788.339 SLUG l.OOE+OO OW-l* 1066186.760 1845549.167 SLUG 9.94E-01 OW-2* 1066391.704 1845765.443 SLUG 1.12E+OO OW-3* 1066031.665 1845901.718 SLUG 3.93E-01 MW013* 1063194.865 1846819.986 SLUG 2.03E+OO CJC Aquifer MW-8 1069314.016 1845853.561 SLUG 2.21E-Ol MW-9 1067031.111 1846943.760 SLUG 4.27E-Ol MW-10 1065231.208 1845930.929 SLUG 1.30E-Ol MW-12 1068338.485 1843101.327 SLUG 2.05E-02 MW-18 1068101.780 1844187.769 SLUG 2.84E-02 MW-lD 1067745.621 1845729.227 SLUG 6.01E-01 MW-2D 1076453.633 1846204.016 SLUG 1.17E+OO MW-3D 1068262.355 1850885.257 SLUG 8.58E-01 MW-4D 1058085.889 1843973.820 SLUG 3.49E-01 MW-5D 1066050.550 1839738.721 SLUG 3.15E-01 MW-6D 1071109.513 1840342.789 SLUG 3.09E+OO MW-7D 1085262.952 1821950.447 SLUG 7.88E-Ol MW-13 1087151.313 1837276.025 SLUG 3.77E-Ol MW-14 1073323.069 1826004.312 SLUG 3.91E-01 MW-15 1046106.941 1833429.170 SLUG 4.02E-Ol MW-16 1052711.248 1839372.032 SLUG 1.57E-01 MW-17 1049043.768 1845199.807 SLUG 3.53E-01 PW-2 1065502.113 1828469.872 PUMPING 6.76E-Ol PW-3 1061781.065 1855490.041 PUMPING 2.04E-01 FMW-1D 1038992.757 1837942.633 SLUG 5.72E-02 FMW-5 1047388.096 1851772.499 SLUG 1.62E+01 MW008* 1051143.178 1847916.098 SLUG 1.15E-01 MWOll* 1053254.460 1846273.765 SLUG 7.78E-01 MW015* 1047338.257 1852001.673 SLUG 8.21E-01 M7* 1063063.308 1845949.375 SLUG 1.46E-02 *UNIT 1 MONITORING WELLS Rl3 063624.04/08 Rev. 1 FIGURES TABLES TABLE 1 LIST OF UNIT 1 USEABLE MONITORING WELLS NAVD88 AVERAGE WELL UTME-NAD83 UTMN-NAD83 ELEVATION OF GROUNDWATER NORTIDNG (FT) EASTING (FT) CENTER OF ELEVATION SCREEN(FT) (FT MSL) (FT) MW001 1068639.785 1844591.481 819.019 829.044 MW002 1065323.863 1844512.707 813.866 818.746 MW003 1064780.635 1847240.943 814.621 830.187 MW004 1048241.82 1850566.251 510.986 513.462 MW005 1048478.619 1852327.073 511.970 510.829 MW006 1051490.434 1848058.08 517.898 525.032 MW007 1051457.886 1847668.138 524.657 526.696 MW008 1051143.178 1847916.098 519.019 521.392 MW009 105093 7.134 1847663.175 521.724 522.353 MW010 1051190.923 1847654.819 520.785 525.530 MW011 1053254.46 1846273.765 556.208 553.501 MW012 1051496.629 1847989.841 433.984 524.938 MW013 1063194.865 1846819.986 817.562 818.119 MW014 1047702.993 1848449.195 499.924 509.194 MW015 1047338.257 1852001.673 499.696 509.629 MW016 1046624.393 1857060.846 489.631 505.201 MW501 1065915.302 1847763.011 801.310 823.475 MW502 1068157.02 1847501.148 798.879 825.515 MW-936 1067072.771 1845567.683 821.817 829.617 MW-937A 1067314.054 1845915.749 824.771 830.977 MW-937B 1066810.963 1845242.275 821.967 831.996 MW-937C 1067169.503 1845788.389 817.128 830.286 MW-937D 1067009.024 1845928.659 819.063 830.575 MW-937E 1066690.45 1845650.623 820.153 832.181 MW-937F 1066741.124 1845145.06 823.857 831.912 M2 1069044.579 1843572.398 743.108 792.368 M7 1063063.308 1845949.375 720.070 706.895 OWl 1066186.76 1845549.167 814.655 834.855 OW2 1066391.704 1845765.443 815.774 834.104 OW3 1066031.665 1845901.718 819.944 834.137 OW4 1066191.637 1846070.13 818.116 832.859 OW5 1065894.242 1845756.706 821.256 834.786 Rl3 063624.04/08 Rev. 0 TABLE2 LOCATION AND ESTIMATED HYDRAULIC CONDUCTIVITIES OF TEST WELLS NAME TYPE OF AQUIFER NORTHING EASTING K(FT/DAY)

MW937F GRAYDON CHERT 1066741.124 1845145.060 3.65E-01 MW937C GRAYDON CHERT 1067169.503 1845788.339 l.OOE+OO OW-l GRAYDON CHERT 1066186.760 1845549.167 9.94E-01 OW-2 GRAYDON CHERT 1066391.704 1845765.443 1.12E+OO OW-3 GRAYDON CHERT 1066031.665 1845901.718 3.93E-01 MW008 COTTER-JEFFERSON 1051143.178 1847916.098 1.15E-01 MWOll COTTER-JEFFERSON 1053254.460 1846273.765 7.78E-01 MW013 COTTER-JEFFERSON 1063194.865 1846819.986 2.03E+OO MW015 COTTER-JEFFERSON 1047338.257 1852001.673 8.21E-01 M7 COTTER-JEFFERSON 1063063.308 1845949.375 1.46E-02 R13 063624.04/08 Rev. 1 TABLE3 LOCATION AND AVERAGE WATER LEVEL MEASUREMENT OF UNIT 2 FSAR MONITORING WELLS AVERAGE LOCATION NORTHING EASTING GROUNDWATER ELEVATION (FI' MSI) Ora' don Chert Aquifer PW-1 1067801.65 1845747.19 829.77 MW-2S 1076444.82 1846189.87 770.36 MW-3S 1068236.86 1850889.85 805.99 MW-5S 1066063.58 1839748.89 794.02 MW-6S 1071137.82 1840344.23 814.46 MW-8 1069314.02 1845853.56 828.96 MW-9 1067031.11 1846943.76 827.45 MW-10 1065231.21 1845930.93 823.70 MW-12 1068338.49 1843101.33 826.97 Cotter-Jefferson Aquifer MW-1D 1067745.62 1845729.23 553.26 MW-2D 1076453.63 1846204.02 552.88 MW-3D 1068262.36 1850885.26 553.20 MW-4D 1058085.89 1843973.82 553.23 MW-5D 1066050.55 1839738.72 555.88 MW-6D 1071109.51 1840342.79 553.34 MW-13 1087151.31 1837276.03 544.19 MW-14 1073323.07 1826004.31 523.04 MW-15 1046106.94 1833429.17 516.76 MW-16 1052711.25 1839372.03 530.60 MW-17 1049043.77 1845199.81 528.65 PW-2 1065502.11 1828469.87 517.68 PW-3 1061781.07 1855490.04 560.89 Missouri River Aulluvial Aquifer FMW-1S 1038995.53 1837956.06 507.69 FMW-5 1047388.10 1851772.50 508.73 FMW-6 1040481.32 1851066.54 505.59 FMW-7 1039841.12 1849706.88 505.84 FMW-8 1039529.50 1848383.31 505.62 FMW-9 1039620.36 1846762.66 506.53 FMW-10 1039680.35 1845265.75 506.87 FMW-11 1039136.45 1839487.41 507.40 FMW-12 1045810.79 1857168.19 504.25 Rl3 063624.04/08 Rev. I TABLE4 SUMMARIES OF SITE HYDRAULIC CONDUCTIVITIES NAME NORTIDNG EASTING TEST TYPE K(FT/DAY)

Graydon Chert Aquifer PW-1 1067801.652 1845747.186 SLUG 7.06E-02 MW-2S 1076444.815 1846189.867 SLUG 1.64E-01 MW-3S 1068236.859 1850889.852 SLUG 9.02E+OO MW-5S 1066063.580 1839748.889 SLUG 5.78E-02 MW-6S 1071137.817 1840344.234 SLUG 7.05E-03 MW937F* 1066741.124 1845145.060 SLUG 3.65E-01 MW937C* 1067169.503 1845788.339 SLUG l.OOE+OO OW-l* 1066186.760 1845549.167 SLUG 9.94E-01 OW-2* 1066391.704 1845765.443 SLUG 1.12E+OO OW-3* 1066031.665 1845901.718 SLUG 3.93E-01 MW013* 1063194.865 1846819.986 SLUG 2.03E+OO CJC Aquifer MW-8 1069314.016 1845853.561 SLUG 2.21E-Ol MW-9 1067031.111 1846943.760 SLUG 4.27E-01 MW-10 1065231.208 1845930.929 SLUG 1.30E-Ol MW-12 1068338.485 1843101.327 SLUG 2.05E-02 MW-18 1068101.780 1844187.769 SLUG 2.84E-02 MW-1D 1067745.621 1845729.227 SLUG 6.01E-01 MW-2D 1076453.633 1846204.016 SLUG 1.17E+OO MW-3D 1068262.355 1850885.257 SLUG 8.58E-01 MW-4D 1058085.889 1843973.820 SLUG 3.49E-01 MW-5D 1066050.550 1839738.721 SLUG 3.15E-01 MW-6D 1071109.513 1840342.789 SLUG 3.09E+OO MW-7D 1085262.952 1821950.447 SLUG 7.88E-01 MW-13 1087151.313 1837276.025 SLUG 3.77E-01 MW-14 1073323.069 1826004.312 SLUG 3.91E-01 MW-15 1046106.941 1833429.170 SLUG 4.02E-01 MW-16 1052711.248 1839372.032 SLUG 1.57E-01 MW-17 1049043.768 1845199.807 SLUG 3.53E-01 PW-2 1065502.113 1828469.872 PUMPING 6.76E-01 PW-3 1061781.065 1855490.041 PUMPING 2.04E-01 FMW-1D 1038992.757 1837942.633 SLUG 5.72E-02 FMW-5 1047388.096 1851772.499 SLUG 1.62E+01 MW008* 1051143.178 1847916.098 SLUG 1.15E-01 MWOll* 1053254.460 1846273.765 SLUG 7.78E-01 MW015* 1047338.257 1852001.673 SLUG 8.21E-01 M7* 1063063.308 1845949.375 SLUG 1.46E-02 *UNIT 1 MONITORING WELLS Rl3 063624.04/08 Rev. I FIGURES I A Jr I i .0i', I i! I' I r A s s l. i i '-,. E ' ,. \.J "" 1* * ... ,l*t A..

.. *. j :r. tv:(7" -* '-'-* l :t:(*i Fetl ;. ., ; .. Figure 1 -Site Location Groundwater Model Report AUGUST2008

.wwm Unrt Descriptions Quaternary

---iC9!i:J Alluvium 4[]!!!]

Group Pennsylvania I*F\1') Pennsylvanian.

undifferentiated I Cabaniss Subgroup Osagean Series Mississippian

-Kinderhookian Series Devonian ---i-Devonian System Ordovician, undifferentiated

--Pre-Wisconsin Glacial Limit IQ!i!!J St. Peter and Everton Ordovician Cotter and Jefferson City formations

[§!] Roubidoux Fonmation l!liJ Gasconade Dolomite Cambrian --jl Cep I Eminence and Potosi formations

+Anticline

+ Monocline CJ Countyline Streams/Rivers 0.75 1.5 3 Miles lllllEi REFERENCE CENTER POINT OFP\.AHT sne IS AS THE MDPOIHT BETWEEN EXJSTING REACTOR R)lt CALJ.AWA.Y PlANT UNrT 1 N<<J REACTOR FOR CALJJ.WAY Pl.AHT UNrT 2. -MODNR.Z007 ESRI , 2007 Figure 2 -Site Area Geologic Map Groundwater Model Report AUGUST2008

I .. I .. X Locat i on Map Y' "'l .. -I

_I '\ -> , . " .. *.g ;.-. :: .. Z' I ] L_ L ... -.. J REFERENCE.

born CaHaway Plant Unh 1 FSAR (AmerenUE.

2004) 2.5-25 (Reconnaissanoe GeolOgiC Map. Site Area) and F.gure 2 S-36 (Generalized Subsurtaoe Sections) ...

"'"'* K* .. *-

LEGEND Quaternary AlluVIum Ouatemal)'

Undiffetentiated Pennsylvan i an U ndiffetenbated u D I.*J .. ., , , ,

J-1' 'i-1 -f ... ... MISSISS!pphlln Undiffereot*ated Devonian Undifferent i ated OrdoVICian UndKferentiated

\ L .. il' .,, " *,_ !': r t:** i l: Figure 3 -Site Area Geologic Cross Sections Groundwater Model Report AUGUST 2008 System Mississippian Southern Missouri Modified from lmes and f:mmett.1994 Hydrogeologic unit Western Missouri, Kansas and Nebraska Northam Missouri Ozartc confining unit ... E .,._ ___ _;;... __ , '1 I t Devonian Silurian

  • Ordovician I i: 1------t t!

Cambrian 'Contains freshwater 2Contarns saline water or brine 'Poorfv known Reference Groundwater Atlas of the United States, Segment 3, USGS, 1997. Figure 4-Aquifer Systems of Northern, Western, and Southern Missouri Groundwater Model Report AUGUST 2008 A / .; Hyarogeologlc Study Area & Unit 1 Montonng Wells A un i t 2 r.1onotor.ng Wallo O i scnarge L"'e USt*S 7

().....,: l****u ....

MDtt':O'"

i'l"'dRI!'or.-

194:. 2.000 <1.000 G.OOO 8.000 -=-eet Figure 5 -Location of Unit 1 & 2 Monitoring Wells and Discharge line Groundwater Model Report A A' Figure 6 -Groundwater model finite-difference grid overlain on digital elevation model Groundwater Model Report August2008 Figure 7 -Layer 1 Active Areas in white Groundwater Model Report Mav 2008

. .,. r1 * *

  • Figure 8 -Layer 2 Active Areas in white Groundwater Model Report AuQust2008 Figure 9-Layer 3 Active Areas in white Groundwater Model Report August 2008 1'11 1 5 _1'114fi *r
  • 1'11 1'

... -

I -. < ** -. Figure 10-Layer 4 Active Areas In white Groundwater Model Report Mav 2008 Figure 11 -Refined grid spacing around the Unit 1 areas Groundwater Model Report August 2008 Figure 12-Layer 1 Boundary Conditions Groundwater Model Report AuQust 2008 Figure 13-Layer 2 Boundary Conditions Groundwater Model Report Auaust2008 NU;1D --.

  • -_.._, Figure 14-Layer 3 Boundary Conditions Groundwater Model Report August 2008 NU;t6 NU;tS . FNa:.F=IL-0" L l "r
  • Nu;t'J .I

"'tftUillS ,

  • Figure 15-Layer 4 Boundary Conditions Groundwater Model Report August 2008 Figure 16 -Layer 1 Hydraulic Conductivity Groundwater Model Report AuQust2008 Figure 17-Layer 2 Hydraulic Conductivity Groundwater Model Report Auaust 2008 Figure 18-Layer 3 Hydraulic Conductivity Groundwater Model Report AuQust 2008 Figure 19-Layer 4 Hydraulic Conductivity Groundwater Model Report Mav 2008 1.5 0.8328186 0.8328186 0.06-0.06 0.25 0.25 1.2 1.2 30 30 750 750 1 1 1.5 1.5 1.6 1.6 2 2 8.92374 8.92374 10 10 0.534472 0.534472 0.881332 0.881332 1.453297 1.453297 0.4796302 0.4796302 2.66646 2.66646 -II: 0.0003042147 P' r 0.00012 r 0.0119346 P' r 0.0001 p r 2.29668E*6 r; r 750 p r 0.00065 p r 0.001 p r 1E*5 R' r 1.8 w r 1.6 p-: r 1 p r 0. 0005344 72 w r 0. 000881332 r 0. 001453297 p r 0. 0004796302 p r 0.00266646 w r Reset Qrder I ,Clean Up Advanced > > I QK I I Figure 20-Hydraulic Conductivity Table Groundwater Model Report Auaust 2008

"" 2 ......., "" -ccn leo i 0 ca u 497 Calculated vs. Observed Head : Steady state 597 " " " /*' "' ,.* 697 Observed Head (ft) " 797 Iii Layer #1 e Layer #2 A Layer #3 V Layer #4 95% confidence interval 95% interval Num. of Data Points : 63 o Max. Residual:

14.625 (ft) at MVV01211 Min. Residual:

-0.027 (ft) at MVV01411 Residual Mean: 1.744 (ft) Abs. Residual Mean: 3.648 (ft) Note: Image is a direct export from Visual MODFLOW Premium Version 4.2 Waterloo Hydrogeologic, Inc., Schlumberger Water Services, 2006. Refer to text for detailed description.

standard Error of the Estimate : 0.58 (ft) Root Mean Squared: 4.885 (ft) Normalized RMS : 1 .478 ( '% ) Correlation Coefficient : 1 Figure 21 -Calibration Graph Groundwater Model Report August 2008 Note: Image is a direct export from Visual MODFLOW Premium Version 4.2 Waterloo Hydrogeologic, Inc., Schlumberger Water Services, 2006. Contours are steady-state groundwater elevations in feet msl. Model scale is shown on axes in feet. Refer to text for detailed description.

Figure 22 -Layer 1 Hydraulic Head Groundwater Model Report August 2008 Note: Image is a direct export from Visual MODFLOW Premium Version 4.2 Waterloo Hydrogeologic, Inc., Schlumberger Water Services, 2006. Contours are steady-state groundwater elevations in feet msl. Model scale is shown on axes in feet. Refer to text for detailed description.

Figure 23 -Layer 2 Hydraulic Head Groundwater Model Report August2008 Note: Image is a direct export from Visual MOD FLOW Premium Version 4.2 Waterloo Hydrogeologic, Inc., Schlumberger Water Services, 2006. Contours are steady-state groundwater elevations in feet msl. Model scale is shown on axes in feet. Refer to text for detailed description.

Figure 24 -Layer 3 Hydraulic Head Groundwater Model Report August 2008 Note: Image is a direct export from Visual MODFLOW Premium Version 4.2 Waterloo Hydrogeologic, Inc., Schlumberger Water Services, 2006. Contours are steady-state groundwater elevations in feet msl. Model scale is shown on axes in feet. Refer to text for detailed description.

3?802 Figure 25 -Layer 4 Hydraulic Head Groundwater Model Report August 2008

\_ --+-\, , ..... ) I A . .IU I I \ ' / .... I \ *! ) MW-2S C'*:r.. * ;* * (771).36). ,_2__.,--:; -s--* r ' I t \

(81 ** 46) . . ,

'* \ C' LEGEND $ . r* / t -"( _.,--J / / .-* //-PW-1 C) Pumping Well Location ' " ,; (829.77) (Groundwater Elevatron ft msl) MW-2S Monitoring Well Location (770.36) S (Groundwater Elevatron rt msl) --Hydrogeologic Study Area --Contour Interval-10ft REFERENCE USGS I 100K Topographll:

Maps Mokane East & Reform Maps edoted 1985 ,. \ 820 / j IQ'*' s '-M -MW001 !* , $(829.04)

'* t./ M 1\ \ i J \ . ,-., / *( ,., (825:'5 ) .S 0 ,-1.ooo 2 ooo 3 ooo 4 .ooo Feet Figure 26-Potent i ometric Surface Map Chert Aquifer Groundwater Model Report August2008

", , . * , ,_.* ,r-'¥..'-r-::.P '* . \ I ,\ -,. . \,J;' .'f: -.\ . *.I ;.l .,.\ *;., '*"

.. 1.: \;. I. .*; lo\ \ " .,. y

..,.. -.... ',* ' .' ..... . ., '.l. ' '

... '* I '* ....... :I t;.,.., .... ! . .-r .* . '\ ., ' *, ' '! ' .... ' '*I -__,-..J *; ' ,*' . * .' .. j MWOOS.( . / *: . . :.c, . . I ..3' . (5 1 0.83); \ . : . . . I \ ...... . . f** i .;. ... .. * ' . . *.. .* . :'"** . . .... . ::..._, .. , ... _,. *** .:_ . __ ......... .#' "....:..., (605.21 y -.. ""' * -

Ji/

  • 7 ..

., *'I I I. I' I / \ **)*," ' ..... ,.,.1141\

_.._Jr. / / ;'.. <. .::; ' \ FMW-6 y *,

  • FMW*1S

./

< / ;' lr' FMW-8 / . .. . / I *f . (507.69) 1 505* FMW-7 . / .*I" -' / t** J FMW-10 FMW-1 1 ._ . S -/ .. ! / (507 4) .. s (505.84) / .... . ' , , 1 (506.8) So

  • i .. * "' : * *-/ . 0 O ' E

--.,.s*"'*--!!l'--------""--------

-*;*------- " "... *r;;;.*.,.----* ---. *

..

-* I * , _, LEGEND FMW-5 $ (508.73) Monitoring Well Location (Groundwater ElevatiOn ft msl) *

  • Hydrogeologic Study Area Contour Interval
  • 1 ft REFERENCE USGS 1 lOOK Topograph i c Maps Mokane Easl and Morrison Maps 1985 0 1,500 3.000 4 , 500 6.000 Feel Figure 27 -Potentiometric Surface Map Missouri River Alluvial Aquifer Groundwater Model Report August2008

,_ * .I \I MW-14 # (523.041' s ,, * * ' ' I f I I ' ' I .. ,, , ' ,., . ' tMI-13' #(544.19}.

,. -s ' .. ,. I " ' ' ,, ' ' MW-20, (552.88) ' s ' MW*1D -(553.26) *S ' ' ,,_ .. ! I MW*3D (553.2) s ... ,, ,_ ' , * * # tw.3 swLo.a9) , '----...:50:;;..

,' MW012

4) (526 ,'7) MW006 MWJU llQ (525.03) 51!.53) IP MWOOB MW009 (521.39) MW-17 S (522.35) (528.65) ;:"--* 1 r ,, '-* __ _ * ', ' I I I ' ' ' ' ' **I I I I I I I I I *------* *--== ,IT, .. *: ...... _ * * * * * * * * * * * * * * ...... -. * * * .... _ *
  • I LEGEND PW-2 -. Pumping Well Location (517.68) \. (Groundwater Elevation ft msl) MW-1 D S Monitoring Well Location (553.26) (Groundwater Elevation ft msl) Hydrogeologic Study Area Contour Interval -1 0 ft 0 3.500 7,000 10.500 14.000 Feet REFERENCE. USGS 7.5-minute Quadrangles.

Mokane East. Morrison.

Readsv*lle.

& Reform Photo revised t985 Missouri Spatial Data Information Service Webs*te http://www.msd*s missou.....,n"'"e""du,_i

_______________

...___, Figure 28 -Potentiometric Surface Map Cotter-Jefferson City Aquifer Groundwater Model Report August2008 Figure 29 -Cross-Section of Groundwater flow field Groundwater Model Report August 2008 AB is Line of cross section B Figure 30 -Unit 1 Particle Release Groundwater Model Report August 2008 c 0 :;:::: u Q) "' t: fl) 0 fl) Q. e Q) D:: 0 a; 00 Q) Q u , Q 0 N :e ::i -"' ... fl) a.. Q) :I .... ; 0) -:I '2 , <( ;:) c ::I .... e C") (!) ::I en u::

Figure 32-Unit 1 Particles to Layer 4 Groundwater Model Report May 2008 Figure 33 -Periphery Particle Release Groundwater Model Report AuQust 2008

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