ML20153B976

Forwards Addl Info Suporting Util 880624 Proposed Rev of Tech Spec 3/4.7.13 Re Use of Groundwater Level Monitors,Per NRC D Hood Request

ML20153B976
Person / Time
Site:	McGuire, Mcguire
Issue date:	08/25/1988
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20153B981	List: ML20153B976 ML20153C016
References
NUDOCS 8808310174
Download: ML20153B976 (50)

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1ce President Charlotte, N C 28242 Nuclear Production (704)3:34531 DUKE POWER August 25, 1988 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.

20555

Subject:

McGuire Nuclear Station Docket Nos. 50-369 and 50-370 Technical Specification 3/4.7.13, Groundwater Level Additional Information Gentlemen: On June 24, 1988, Duke submitted to the NRC a letter stating McGuire Nuclear Station's proposed use of groundwater monitors that would be removed frea the McGuire Technical Specifications (T.S.) pursuant to Duke's proposed T.S. revision submitted by my letter dated January 27, 1988. The June 24, letter also addressed actions that would be taken regarding the 1988 update of the McGuire Final Safety Analysis Report (FSAR) and a procedure that would be prepared to address penetration tubiug for interior groundwater monitors. Subsequently, Mr. D. Hood of NRC ONRR informed Duke that a draft of the proposed FSAR changes, the groundwater monitor procedure, and a Selected Licensee Commitment would need to be submitted to NRC for review prior to final resolution of the proposed T.S. revision as requested by Duke. Therefore, the following attachments are provided: o Attachment Ona provides the draf t McGuire FSAR update for sections regarding groundwater control and instrumentation; o Attachment Two provides the draft Selected Licensee Commitment for the Groundwater Level Monitoring System; and, o Attachment Three provides the Groundwater Monitor Loop Calibration procedure that contains steps to address the penetration tubing for interior groundwater monitors at McGuire. Should there be any questions regarding this submittal, please contact S.E. LeRoy ct (704) 373-6233. Very truly yours, . M p Hal B. Tucker SEL/218 8808310174 880825 Acol PDR ADOCK 05000369 P PDC i

s Document Control Desk August 25, 1988 i Page 2 Attachment xc Dr. J. Nelson Grace Mr. Dayne Brown, Chief Regional Administrator, Region II Radiation Protection Branch U.S. Nuclear Regulatory Commission Division of Facility Services 101 Marietta St., NW, Suite 2900 Dept. of Human Resources Atlanta, CA 30323 P.O. Box 12200 Raleigh, NC 27605 Mr. Darl Hood Mr. W.T. Orders U.S. Nuclear Regulatory Commission NRC Resident Inspector Office of Nuclear Reactor Regulation McGuire Nuclear Station Washington, D.C. 20555 0 i i t l

i o s Attachment One Proposed Draft For 1988 McGuire FSAR Update Groundwater Related Sections

DRAFI However, the impact of possible drought conditions has been studied. As shown in Table 2.4.11-1, the minimum average inflow for various flow conditions and recurrence intervals is given. As shown in the table, the total of the evapor-ative losses due to the heat dissipation of the condenser cooling water at McGuire and Marshall Steam Stations, and the minimum average flow required downstream of Cowans Ford, is greater than the minimum average inflow; however, available storage from Lake Norman is more than adequate to maintain the required minimum flows. The evaporative losses do not include natural evaporation from Lake Norman which is estimated to be 40 inches per year (8). The average rainfall over Lake Norman, 44 inches per year, more than restores the loss by natural eveporation. 2.4.12 ENVIRONMENTAL ACCEPTANCE OF EFFLUENTS Any radioactive liquid ef'iuents are released to the condenser circulating water discharge. There is no credible accidental release of radioactive liquids to groundwater since any spills in the station are collected in floor drains and sumps for treatment if required. Since rainfall rather than impounded surface water is the source of groundwater in the area, there is no risk af groundwater contamination. Station discharge concentrations do not exceed limits applied to public drinking water. Also, some decay occurs after discharge and there is additional dilution downstream of Cowans Ford Daa. The expected release concentrations are shown in Subsection 11.2.8. Chemical discharges are first retained in the Conventional Waste Water Treatment System for appropriate treatment and then are discharged to the Catawba River below Cowans Ford Dam. The discharge concentrations do not exceed limits applied by appropriate governmental agencies. A detail study of thermal eff'ects of the condenser cooling water discharge is contained in McGuire ER-OLS, Section 4. 2.4.13 GROUNDWATER 2.4.13.1 Description and Onsite Use The station site lies within the groundwater region known as the Charlotte area, which is part of the Piedmont Groundwater Province. Groundwater in this area is derived entirely from local precipitation and is contained in the pores that occur in the weathered material above the relatively unweathered rock and in the fractures in the igneous and metamorphic rock. The water table varies from ground surface elevation in valleys to more than 100 feet below the surface on sharply rising hills. A full discussien of site ground-water hydrology is contained in Appendix 28. Groundwater is not a water source for the station. 2.4.13.2 Sources Groundwater is used as a domestic water supply for the few residences in the area immediately surrounding the site. This is the only use of groundwater in 1 2.4-21 12/83

s R, ", P o I I j j the foreseeable future for this area. The locations of existing wells in the area are shown on Appendix 28, Figure 28-1, and data on these wells are given in Appendix 28, Table 28-1. The occurrence, location, and movement of ground-water at the site is controlled primarily by the water level in Lake Norman, which borders the site on the north. Flow of groundwater is normal to ground-water contours shown on Appendix 28, Figure 28-2. Soil permeability values for the area range from about 200 to 300 feet per year (Appendix 2B, Table 28-3). A typical section of the groundwater gradient is shown in Appendix 28, Figure 28-3. No reversal of groundwater flow is expected due to the topography. The only expected groundwater recharge areas within the influence of the station are adjacent to the Standby Nuclear Service Water Pond and the Waste Water Collection Basin as shown on Figure 2.1.2-1. 2.4.13.3 Accident Effects Spills of potentially radioactive liquids within the station are not a source of groundwater contamination due to the floor drain systems in the Containment and the Auxiliary Buildings. Liquids cannot seep through the concrete as all sumps are stainless steel lined. Concentrations of cesium and strontium in wells resulting from groundwater movement from the lake to the well are less than any lake concentrations due to the additional decay afforded by the ion exchange action of the soil. Appendix 28, Section 2.6 discusses the ion exchange potential of the soil at the site. An analysis of the potential contamination of domestic wells by Cs and Sr was performed based on the following conservative assumptions: s a. Average groundwater movement rate of 300 ft. per year (Appendix 28, Section 2.3). b. Minimum shoreline to well distance of 100 ft. (Appendix Figure 28-1). c. Effective Cs and Sr movement rates of 1/92 and 1/46, respectively, that of groundwater (Appendix 28, Section 2.6). d. Concentration of Cs and Sr in Lake Norman water as discussed in Section i 11.2.8. The slower movement rates of Cs and Sr in the groundwater due to the ion exchange action of the soil result in sufficient decay time to effect a reduction in concentration of approximately 0.5 and 0.67, respectively, that of the initial Lake Norman concentrations. Due to the proximity of the closest well to its source (100 ft), the possibil-ity of a direct path for groundwater flow was not overlooked. In this case, the Cs and Sr concentration in the well would be just equal to the Lake Norman concentration. These results are tabulated below and in either case the concentrations are i substantially below 10 CFR 20 limits. 4 2.4-22 12/83

m-~ 1 Concentration in Domestic Fraction of Isotope Well Water (pCi/ml) 10 CFR 20 Limits Ground Water Movement Ground Water Movement 300 ft/yr Instantaneous 300 ft/yr Instantaneous ~ ~ ~ Cs 137 2.2 x 10 11 4.4 x 10 11 1.1 x 10 6 2.2 x 10 8 ~ ~ Sr 90 5.0 x 10 15 7.4 x 10 15 1.7 x 10 8 2.5 x 10 9 As previously stated there is no credible accidental release of radioactive liquids to the groundwater due to containment provided by Category 1 structures. However, an accidental release of liquid radioactive material based upon assumed failure of the floor drain tank (Table 12.1.2-2) and subsequent failure of a Category 1 floor is postulated to demonstrate the potential radiation contamination to groundwater. A postulated rupture of the floor drain tank would result in a spill of radioactive material, which would eventually flow into the groundwater sumps of the Category 1 buildings. Groundwater or contam-inated liquid collected in sumps A or B would be pumped to the Turbine Building sumps. Normal sump discharges are pumped to the Conventional Waste Water Treatment System for treatment prior to release to the Catawba River. If the radiation monitors in the discharge lines to the Conventional Waste Water Treatment System indicate that radioactive materials are present in the sump discharge, the sump contents may be directed to the Liquid Waste Monitor and Disposal System. Assuming the flow into the Conventional Waste Water Treatment System is not terminated upon the receipt of a high radioactivity alarm, adequate holdup capacity is available in the Conventional Waste Water Treatment System to contain the postulated spill. Ground water or contaminated liquids collected in sump C would be pumped to a free outfall at the storm drain system which discharges into the SNSW Pond. Inflow to the SNSW Pond is passed to the Waste Water Collection Basin through the SNSW Pond outlet facility. Sufficient holdup capacity is provided in the Waste Water Collection Basin to contain the postulated spill. As shown on Figure 25-2A, the SNSW Pond and the Waste Water Collection Basin are down gradient from all wells in the area, and contamination of the groundwater supply is not possible. If the rate of flow into the three sumps is assumed equal to the capacity of the three sump pumps (750 gpm), the total postulated spill can be pumped from the Auxiliary Building sumps to the Turbine Building sumps and/or the SNSW Pond in approximately 15 minutes. 2.4.13.4 Monitoring or Safeguard Requirements The potential for groundwater contamination is very low thus groundwater is not routinely sampled for radioactivity as part of the environmental radio-logical monitoring program. A discussion of the environmental radioactivity monitoring program is provided in Section 11.6. 2.4-23 12/83

LRA T 2.4.13.5 Design Bases for Subsurface Hydrostatic Loadings As shown in Appendix Figure 28-2, preconstruction groundwater levels were approximately 10 to 35 feet below plant yard grade. Reactor, Auxiliary and Turbine Building excavations in soil and weathered rock below plant yard grade were dewatered by eductor wellpoints located on the western, northern and eastern perimeter of the excavation. Excavations in rock below plant grade were dewatered by excavated sumps located at convenient construction locations. A permanent Category I underdrain groundwater system is installed as shown on Figure 2.4.13-1 and 2 to maintain the groundwater level below elevation 717.0 for the Reactor Building and elevation 712.0 for the Auxiliary Building. The underdrain system consists of a grid of interconnected flow channels at the top of rock or top of fill concrete below the foundation slabs. The grid of flow channels drains the entire foundation of the Reactor Building, and Auxiliary Building complex except for deeper pits which are designed for hydrostatic loads. Drilled holes through fill concrete into rock, at a maximum spacing of 8 feet on center, permit groundwater to flow from beneath the fill concrete slabs into the flow channels. All channels in the grid system drain by gravity to three sumps located in the Auxiliary Building. (A and B, 10 ft. x 10 ft x 15 ft, deep, and C, 17 ft. x 17 ft. x 12 ft. deep.) As shown on Figure 2.4.13-1, an exterior wall drain system composed of two separate flow mediums or pathways, extends around the foundation perimeter and drains directly to sump C. This wall drain consists of a 2 ft. minimum thickness zoned sand and stone filter, placed vertically from the bottom of the excavation to a point 5 feet below yard grade, and an 8" perforated metal pipe which is continuous horizontally around the exterior wall at the bottom of the filter. Groundwater collected in the sumps is pumped to the yard storm drain system or to Turbine Building sumps. Two 250 gpm Category I pumps, each capable of handling the total flow into the sumps for a pump cycle, maintain the water level automatically in each sump. In the unlikely event a pump fails to start and water rises above the normal operating level of the sump, the second pump will automatically start and will continue to operate as required. If either or both pumps fail to start, an alarm will alert the operator. Since the three sumps are interconnected by the grid drain channels at Elevation 712 msl, all six pumps are available to discharge groundwater. In the unlikely event that two pumps become inoperable in any one sump, groundwater would flow through the many redundant channels to the other sumps. Details of the underdrain system, wall drain system, and sumps are shown on Figure 2.4.13-2. Calculations for estimating the groundwater flow are presented in Appendix 20 Subsection 5.1.1. System description and instrumentation and control for the groundwater sump pumps are presented in Subsections 9.5.8 and 7.6.11. Four independent discharge lines, each capable of handling the system capacity are provided to discharge groundwater from the Auxiliary Building sumps. Groundwater collected in sumps A and B is normally pumped to the Unit 1 Turbine Building sump by the A pump in either sump. If the B pump in either sump is required, groundwater is pumped to the Unit 2 Turbine Building sump. Groundwater collected in sump C is pumped to a free outfall at the storm drain system through separate discharge lines for each pump. The free outfall j drains to the storm drain system and prevents siphoning to the groundwater sump. In the event the storm drain system becomes blocked, the sump discharge 2.4-24 12/83

( t' .mene a k 5 I Allu$ L 1 would. flow to adjacent catch basins or would discharge off the yard by sheet flow. The invert of the free outfall is located two feet above yard grade to prevent flooding of the Groundwater Orainage System during the local Probable Maximum Precipitation. Multiple redundancy of vital system components will assure the ability of the system to function over the life of the plant. In the unlikely event that a single flow channel or wall drain becomes blocked, groundwater will flow to the sumps through any of the many redundant drain routes available. Six Category 1 pumps, each capable of handling the total estimated flow, will assure the function of the sump. Monitoring of pump operation provides assurance that the zoned wall filter, drains and pumps are properly functioning. Although the wall drain and underdrain prevent a rise in the groundwater around the exterior building wall, calculations are presented in Appendix 28 Section 2.7 for the water level recovery based on the postulated simultaneous blockage of all drains into the sumps. Figure 28-8 shows the results of the h ef p .__p groundwater level recovery calc,ulations.

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.s3., a33 _,__.2 _ = f-cornfoDe@*.)..','*.i.'. n ' L _wun'.'".'."'w?T.i on. Z *"""."".i c**=*v'ii'"' Ti ? 5  : """a-A l .wi ow mv wm wwou wivu i v.p. f'SC groundwater level monitoring program, as described in Section 2.1.2 of Appendix B, has verified the expected construction stage drawdown and the stabilized elevation of groundwater outside the Reactor and Auxiliary building walls. The layout of these groundwater level monitoring wells is shown on FigureffH :-d "igore M. The zone of influence of groundwater drawdown by the groundwater control system is discussed in Appendix 28, Subsectio Is A ) ms,as. w.h \\\\0 d'+ u r m M ** "4 M<j w C 2.1'2'\\ ae er.u.s m i dnw ~ L +. I 3. \\, Qua 2 tw w 'a e.14, ~ a 7 Eleven permanent groundwater monitors are installed around the perime{e7of",M '. the Auxiliary and React'or Building exterior walls to monitor t, e groundwater level in the zoned wall filter. Seven interior monitors, ins 1 ru ted through / holes in the wall, are mounted inside the AuxiliaryOBuilding." (kterior bb monitors, instrumented in cased wells drilled into the 7.oned wall filter, are located outside the Reactor and Auxiliary Building (See Figure 2.4.13-1 for location of monitors). %4 cau.\\ 6cier< dor ( Lsed 8 4 e seven nterio monitors re locate two fee -3 inches bove th top o the frem follenbala f or slab Any oundwate rise 5 inc. 5 above this poin would tomat. ally ( in the ontrol com. Ea exterior onitor ovides t. ee poin of (qe., ala, to aler the pla t operato to a rise in groun water. e first larm point 's set at *he ele tion of he top of e adjac t floor ab in t. buildin The se and ala point i set five et and he third ifteen et above the top of t adjace t floor ab. Any single alarm or any combination of individual alarms will alert the plant feert C 9 operator to a groutiwater rise.-2 D---d4 21 =rti^a !! des & bed in Tarhn 4 r2L 4 S 0cifi;et;wns -wwid ww initietud wiiwn grounc-eter -i;;; ;b:;; th; elevaticr,-- g p.))m,gJm;r._ %. n <3 m__-,3 a__ <m. u, m:. 433 1 w. Since the zoned filter wall drain system is confined by building walls and the compacted earth backfill (or rock excavation at the foundation level) the wall j Nhi 0 r0 fl 00t;-C'; 35-huilt f"n n d i t i o n O th; - 13n,, Ine i.56iniisel speCiii % a i. i e i i a I f ^ are u^ der r="i?" b m w vu sn UcLoDer J1, lyca ieLLer Lv inc iE C. -- E 2.4-25 y p:e x

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== INSERT A Based on design calculations, uplift and overturning of the Auxiliary Building will occur when groundwater rises above elevation 737 Feet Mean Sea Level (MSL). The maximum groundwater elevation is considered to be 760 Feet MSL. This level is based on a full lake level of 760 Feet MSL. The Reactor and Diesel Generator Buildings are designed to withstand overturning if groundwater rises to the maximum elevation. In addition, the Auxiliary, Reactor, and Diesel Generator Building walls are designed for maximum groundwater elevation. The time required for a rise in groundwater from elevation 712 Feet MSL (maintained by the under drain system) to 737 Feet MSL under the most adverse soil conditiona is approximately 20.3 days. INSERT B All eleven monitors provide three points of alarm to alert operators to a rise in groundwater. The seven interior groundwater monitors are located 2 Feet 3 Inches above the top of the adjacent floor slab. The first alarm point is set at 2 Feet 8 Inches above the top of the adjacent floor slab. The second alarm point is set at 5 Feet, and the third alarm point is set at 15 Feet above the adjacent floor slab. For the two exterior groundwater monitors located adj acent to the Reactor Buildings, the first alarm point is set at the elevation of the top of the adjacent floor slab. The second alarm point is set at 5 Feet, and the third alarm point is set at 15 Feet above the top of the adjacent floor slab. The exterior groundwater located inside the Unit 2 Maintenance Staging Building has a first alarm point set at elevation 731 Feet MSL. The second alarm point is set at 5 Feet, and the third alarm point is set at 15 Feet above elevation 731 Feet MSL. The exterior groundwater monitor located adjacent to the Unit 1 Auxiliary Building has a first alarm point set at elevation 716 Feet MSL with the second alarm point set at 5 Feet. and the third alarm point set at 15 Feet above 716 Feet USL. INSERT C Corrective actions as stated in Technical Specification 3/4.7.13, Groundwater Monitoring, is required when groundwater levels for three out of five technical specification groundwater monitors specified in Table 2.4.13-1 of the McGuire FSAR are above the values shown in the table. The six Non-Technical Specification groundwater monitors are identified in the McGuire FSAR Selected Licensee Commitment 16.9-8 along with required actions regarding these monitors. I

O DRA-T drain system will remain passive during earthyake as will the underdrain system. Since the top of the zoned wall filter is 5 feet below plant yard grade there is no credible flood that will affect the underdrain system. There is no credible risk to the underdrain system from non-Category 1 piping systems. Cutoff plates are provided around CCW pipe to prevent seepage along the scil-pipe interface. Plate stiffeners, 7 inches high and spaced at a maximum of 7'-6" along the pipe, provide additional assurance the seepage will not follow the CCW pipe. The postulated failure of the CCW pipe in the yard results in seepage of approximately 38 gpm to the underdrain system. There fore, the failure of the condenser coolireg water pipe will not flood the underdrain system. The zoned wall filter and perforated pipe is not required on the south side of the Auxiliary Building because the adjacent Turbine Building will prevent a rise in groundwater above elevation 735.0. The radius of influence of drawdown due the underdrain system will limit the height that groundwater will 4 rise on the Auxiliary Building walls. Additionally, the Auxiliary Building walls can withstand full hyrdostatic loads to elevation-7 % t in comeination with other loads described in Subsection 3.8.4. 7/.,0. 0 The postulated failure of the Nuclear Service Water pipe has been evaluated to determine the potential for flooding the groundwater underdrain system. The pipes for this system penetrate the zoned wall filter and would result in the largest discharge of water into the underdrain system. The Nuclear Service A Water System is a moderate energy fluid system and has been evaluated according to NRC Branch Technical Positions MEB 3-1 and APCSB 3-1. A throughwall leakage crack, one-half the pipe diameter x one-half the wall thickness, would result in a flow of 666 gpm to the underdrain system. This flow plus the calculated groundwater seepage would result in a total flow of 696 gpm. Since six - 250 gpm pumps are available to discharge groundwater the postulated failure of the Nuclear Service Water pipe will not flood the underdrain system. Walls below plant yard grade are not waterproofed, but waterstops are provided in all construction joints. In the unlikely event that the groundwater level rises outside the Reactor and Auxiliary Building walls, seepage through the wall will not exceed the capacity of the floor drain system. 2.4.14 TECHNICAL SPECIFICATION AND EMERGENCY OPERATION REQUIREMENTS Emergency procedures are detailed in Section 13.3. In an emergency situation, industries and municipalities that utilize Lake Norman and the downstream area as a water supply are notified of possible contamination. 2.4.15 REFERENCES i 1 A Forest Atlas of the South, For?st Service, U.S. Department of i Agriculture, 1969, pg. 8 2 Engineerino Manual for Civil Works, Part III, Chapter 5, April, 1946, Plate 3. I 3 "Hydrology of Spillway Design: Large Structures - Adequate Data" by Franklin F, Snyuer, Journal of the Hydraulics Division, ASCE, Vol. 90, No. Hy3, May, 1964, pg. 239-259, 2,4-26 12/83

GROUNDWATER HYDROLOGY LIST OF TABLES har TABLES Table 28-1 Well Survey Data Tabis 28-2 Rock Permeability Test Results Table 28-3 Soil Permeability Test Results Table 28-4 Results of Physical and Chemical Tests on Groundwater ? I l 1 i 28-111 12/83

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=w GROUNDWATER HYDROLOGY LIST OF FIGURES P FIGURES Figure 28-1 Map Showing Wells Surveyed Figure 28-2 Water Table Contours Figure 28-2A Water Table Contours on May 7, 1975 Figure 2B-3 Typical Groundwater Section-AA Figure 2B-4 Location of Streams, Springs, and Discharge Measurement Points Figure 28-5 Schematic of Equipment Layout and Description of Procedure For Rock Permeability Testing Figure 28-6 Schematic of Equipment Layout and Description of Procedure For Soil Permeability Testing Figure 28-7 Time Plot of Lake Level, Tailwater Level, Groundwater Level and Rainfall Figure 28-8 Plot of Water Level at Structure Versus Rebound Time 28-iv 12/83

GROUN0 WATER HYDROLOGY OF McGUIRE NUCLEAR STATION 1 REGIONAL GROUNDWATER HYOROLOGY The plant site lies within the groundwater region known as the Charlotte area, which is part of the Piedmont Groundwater Province. Groundwater in this area is derived entirely from local precipitation. The surface materials in many loo tions are relatively impermeable with the result that only 10 to 15 inches of the average 43 inches of precipitation percolates to the water table. Groundwater is contained in the pores that occur in the weathered material (residual soil-saprolite) above the relatively unweathered rock and in the fractures in the igneous and metamosphic rock. Although generally the depth to the water table depends on climate, topography and rock type, in the Charlotte are the depth depends primarily on topography and rock weathering because there is little variation in the hydrologic properties of rock types within the area. The water table varies from ground surface elevation in valleys to more than 100 feet below the surface on sharply rising hills. The groundwater level normally declines during the late spring, summer and early fall months as a result of evaporation and transpiration by plants, and, in the fall, when rainfall is low. The groundwater level rises in the late fall and winter when the evaporation potential is reduced. Shallow dug wells are supplied from surface deposits or from the upper decom-posed parts of the bedrock. Many drilled wells of moderate depth are supplied from joints in the crystalline rocks. The water quality is excellent, general-ly low in minerals, except iron. The quantities available are generally small. 1.1 WELL SURVEY i To determine the general groundwater environment surrounding the site, a survey was made of the wells which provide domestic water supplies in the general site area. The locations of existing wells are shown on Figure 2B-1, and data on these wells are given in Table 2B-1. The wells surveyed range from 3 to 6-1/4 inches in diameter, and depths range from 80 to 325 feet. The maximum dis-charge is about 10 gallons per minute. 1 2 SITE GROUNDWATER HYDROLOGY I The occurrence, location and movement of groundwater at the site is controlled primarily by the water level in Lake Norman, which borders the site on the north. Permeability is controlled by the distributions of fractures in the bedrock and by the size and distribution of the pores in the material above

bedrock, Gradients are controlled by topography, fractures and by the eleva-tion of the water in Lake Norman.

2,1 GROUNDWATER LEVELS 2B-1 12/83

o D< I 2.1.1 PRECONSTRUCTION Observations of preconstruction groundwater elevations were made at approxi-mately 100 locations in the immediate vicinity of the site. Based on these observations a contour map showing the water table was prepared (see Figure 28-2). This map shows that the preconstruction elevation of the groundwater along the northern boundary of the site coincides with the elevation of the surface of Lake Norman, and that the movement of the groundwater is generally to the south and southwest. Thus, groundwater moved from the plant site toward the Catawba River or toward the small branches that drain into the Catawba. A cross-section through the site illustrates the relation between the topography, preconstruction groundwater elevation and geology (see Figure 28-3). A water level recorder was installed on boring H-11 in order to monitor fluctu-ations of the groundwater elevation. The record of this variation of H-11 water level versus Lake Norman pond Elevation is shown in Fig. 2B-7. 2.1.2 CONSTRUCTION EFFECTS The groundwater environment in the immediate vicinity of the site will be substantially changed by the construction; however, the effects of changes will be to decrease the slope of the water table and thus te increase the transit time of contaminants moving from the site to any discharge point. Since the bottom elevations of the structures are below the natural water table, an underdrain system has been installed to lower the water table. This underdrain system will remain in service after construction. This will result in a minimum groundwater level of about elevation 712 in the Reactor Building area and a depression of the water table with groundwater flow toward the Reactor Building area from all directions. Under normal condition, the flow from the underdrain system will be discharged into the surface water drainage system. Groundwater elevations measured during construction, are shown in Figure 28-2A. Contours shown on Figure 2B-2A are based on groundwater elevations measured on May 7, 1975 and show the effects of various dewatering projects at the site as well as the presence of the Standby Nuclear Service Water Pond. Discharge from the three sumps used to drain the Auxiliary Building were monitored during the period March 5,1975 to April 1,1975. The average flow from the north sump was 3.6 gpm and the maximum flow during any 24 hour period was 3.8 gpm. The discharge from this sump on May 7, 1975 was 3.64 gpm. The two south drainage sumps each have an average flow of 6 gallons per day. The well point system at the Intake Structure discharges approximately 66.9 gpm directly into Lake Norman. It is scheduled for removal on or about September 1, 1975. The Discharge Canal was unwatered to about elevation 725 feet at the time the water elevations shown on Figure 28-2A were measured. Figure 28-2A provides data for the site groundwater situation with all under-drain systems installed and functioning. Construction dewatering by eductor wells was in progress at the intake excavation northwest of the plant. The discharge canal was not full of water. Otherwise. conditions on May 7, 1975 were similar to those that will exist after all construction is complete. Therefore, Figure 28-2A provides a basis for estimating the extent of the zone i of influence of groundwater and the amount of drawdown at the site boundary, 1 2B-2 12/83

JRAFT ~ Figure 28-2A shows the groundwater aquifier at the site can only be affected locally by the drainage system, since it is bounded on the north by Lake Norman, on the west by the Catawba River, on the south by the NSNW Pond and on the east by a ridge where the groundwater elevation has not been significantly affected by dewatering. The contours also indicate that offsite groundwater users will not be af fected by the lowered groundwater table in the plant vicinity. DuM Cuests4*G A groundwater level monitoring program in the vicinity of the Reactorland Auxiliary Building areashas been initiated to determine any further changes when construction dewatering is discontinued. This program is defined in the plant technical specifications, ad Scle 6/ M<mie 6*A A'"d 4.1-9, Gren/b ' Aw<//?w Y% 5 4,.. 7 2.2 SPRINGS AND SURFACE DRAINAGE A number of small springs are present in the vicinity of the site. These springs occur where the groundwater table or water bearing joints intersect the ground surface. The springs generally occur at the head of the small streams which drain the site. These streams are defined by the topographic map of the site (see Figure ?B-4), and the location and elevation of six of the springs are also shown o -.his map. Discharge measurements were made at several points along the branch i in order to obtain an estimate of the quantity of flow produced by the sirings. The locations of the discharge measurements are also shown on Figure 2e 4. 2,3 PERMEABILITY The permeability of a material is its relative ability to transmit water. The permeability, along with the water table gradient, determines the rate of water movement in the soil or weathered rock pores, and in cracked zones in the rock. The permeability was measured at fifteen locations across the site. Single and double packer systems were used to determine the permeability of the bedrock, and constant head tests in sealed piezometers were employed to measure the permeability of the weathered materials. Figures 2B-5 and 2B-6 show the arrangement of the equipment along with a brief description of the procedure used in determining the rock and soil permeabilities. Table 28-2 presents the rock permeability test results, and Table 2B-3 presents the soil permeability c test results. The permeabilities in the rock were found to be very low, ranging from 0.0 to about 160 feet per year. The highest permeabilities were found in material described as "very soft diorite" and "very soft granite." This is some indica-tion that the very soft coarse grained diorite is more permeable than very soft fine grained diorite. Material classified as "hard diorite" or as "hard granite" had permeabilities that ranged from 0.0 to less than 30 feet per year with values in the lower end of this range occurring more frequently. The soil permeability measurements were generally conducted in the most permea-ble zone of the weathered material-residual soil or saprolite. This is textur-ally described in the drilling logs as "silty fine to coarse sand." l The results of four tests in widely separated holes showed a remarkable consis-tency. The values ranged from about 200 to 300 feet per year. The permeabili-j ty measured in boring H-5, which is much lower than that measured in other ) 2B-2 12/83

Ptl I o l = LNj locations, is discounted because the water table at this location is very near the surface and a head sufficient to produce good results could not be at-tained. Permeability tests performed on soils for Cowans Ford dam at a depth of 7 to 8 feet below the surface indicate a relatively impermeable soil at this level. Permeability as determined from such tests was 16 feet per year. 2.4 MOVEMENT OF GROUNDWATER In general, flow of groundwater is notmal to groundwater contours. The quanti-ty of groundwater movement is controlled by the slope or gradient of the water table and the permeability of the area through which it moves. The velocity of flow is controlled by the gradient, the permeability and the porosity. The shortest groundwater path between the site and the river is by way of springs i in the vicinity of the point marked S-1 on Figure 28-4. The time of travel can-be estimated as approximately 60 to 8 years based on a permeability of 300 feet per year and a porosity of 0.10. The rate of movements in the joints is probably greater, y 2.5 QUALITY OF GROUNDWATER The quality of the groundwater in the vicinity of the site is high and satis

• factory for domestic use without treatment.

Chemical and physical tests were conducted on water from six wells located around the site. The analysis showed the water to be low in mineral content and slightly alkaline. The mineral content in these wells is as low or lower than average values found in the surrounding area. The results of the chemical and physical tests are shown in Table 28-4. The locations of the wells from which the samples were taken are shown on Figure 28-1. I 2.6 ION EXCHANGE POTENTIAL OF SOIL 1 Standard methods of chemical analysis were used to determine the cation ex-change capacity of the soil at the site. Several samples were selected from borings near the center of the site and tested for their ion exchange capacity relative to ions of cesium and strontium. The results of these tests are [ presented in Table 2B-4. The ion exchange capacity of soil affects the rate at which a radioactive j groundwater containment moves through the soil. The rate of movement of the i contaminant depends on the composition of the waste, composition of the soil, and the rate of movement of groundwater. The radioactive contaminant will move less rapidly than the groundwater because it will be absorbed, to some degree, by soil particles. A relationship has been developed 1 which provides [ i l l t Ilome, Y., and Kaufman, W. J., "Studies of Injection Disposal," Proceedings of Second Ground Disposal of Radioactive Wastes Conference, Chalk River, Canada, 1961, pp. 303-321. l 2B-4 12/83

JRAFT an estimate of the effect of ion adsorption on the travel time of a radioactive contaminant. This relationship may be expressed as = [11 + B (1 P) K ) t, t d e where t = time of travel for contaminant g B = bulk density (g/ml) P = porosity d = distribution coefficient (ml/g) K t, = time of travel for groundwater The distribution coefficient provides a measure of the exchange characteristics of the soil. It has been shown: that the distribution coefficient depends on the concentration of the contaminant, the pH of the transporting solution, and on the presence of additional ions in the transporting solution. Comparison of the ion exchange capacity of the soil and the chemical characteristics of the groundwater at the site with values cbtained from laboratory tests (see Prout) for the site in the range 10-100 ml/g for strontium. suggest a value of Kd A conservative travel time for strontium is estimated to be approximately t = [1 + 1.925

3) 10] t, II c

t = [1 + 45] t e y i.e., the conservative travel time for strontium is about 46 times the travel time for water. If the larger value of the distribution coefficient were to be Jsed, the travel time would be increased by a factor of 460 instead of 46. These calculations are based on a value of density equal to 1.925 g/ml (120 lbs/ft3) and a porosity of 0.3. Strontium was used in these calculations because it frequently represents the most critical contaminant. The distribution coefficient for cesium, like that for strontium, varies with pH and the concentration of the isotope solution. At a molal concentration of 5 x 10 8, the soil tested by Prout had a distribution coefficient for strontium that varied from about 10 (pH=3) to a value of approximately 900 (pH=7). For the same concentration and range of pH, the distribution coefficient for cesium varied from about 200 to over 1,600. Therefore, the adsorption of cesium at low values of pH can be predicted to be considerably greater than that for strontium. As a result, the travel time for cesium will also be greater, possibly in the range of about two time to as much as twenty times as long. Prout, W. E., "Adsorption of Radioactive Wastes by Savannah River PLANT Soil," Soil Science, Vol. 86, No. 1. July 1958, pp. 13-17. 28-5 12/83

O Y i" '~' t 2.7 GROUNOWATER RISE FOLLOWING POSTULATED UNDER0 RAIN FAILURE In order to estimate the response characteristics of the aquifer, should a failure of the Category 1 underdrain system occur, the underdrain system was modeled by using a two-dimensional finite difference Solution to the unsteady. flow equations.3 Aquifer parameters were assumed based upon the results'of the e field investigation. Simulations were made with a permeability equal to 300 e feet per year, and an aquifer storage coefficient equal to 0.1. The bottom of the aquifer was assumed to be at elevation 712 feet msl, the elevation of the underdrain system. An infiltration rate was estimated by assuming that 32 percent of the maximum monthly rainf all (March,1973 Mr. Holly, North Carolina) infiltrates to the groundwater system, and that this recharge is. uniformly distributed in time. These assumptions yield a recharge rate of 0.0598 gpd/sq. ft. Initial conditions for the simulation were derived by., suit,ing that the water l table was at steady state at time t:0 (the time of uncerdrain failure). The 4 edge of the structure was assumed to represent an impermeable boundary, and i Lake Norman was assumed to act as a line source at a distance of 300 feet from the structure. The elevation of the water surface in Lake Norman was held at 760 feet throughout the simulation. The results of these simulations are presented in Figure 28 8 which shows water j level at the structure as a function of time after underdrain failure. These curves neglect all storage in the underdrain system, and consider only storage 1 in the aquifer. 3 (98GLW0M i The depth of groundwater below the ground surface, the direction of groundwater movement, and the rate of movement are, to a great estent, controlled by the water surface elevation in Lake Norman. Other important factors which influ-ence the groundwater characteristics are the topography and the permeability of j the soll and rock. Water which moves through the soil and rock beneath the site is discharged through a number of small springs and seeps along the small j streams which drain the site. Measurement of the flow in these streams indi-l cates a discharge 10 to 20 times larger than would be computed from the soll and rock permeabilities and f rom the Groundwater gradients. Th b shows that j the greatest part of the seepage is through rock joints, i j l Although radioactive materials are not expected to enter the groundwater escept as the result of an extraordinary accident. the results of this study show that l J these materials would not readily be dispersed to the environment where people 4 could be exposed. 3 l i i 2Prickett, 1. A. and tonnquist, D. G., "Selected Digital Computer techniques f or Groundwater Resource E valuation," lilinois State Water Survey, Urbana, ) lilinois, Bulletin %,19/1. t i 1 20- fi 12/83 4

Q f TABLE 28-1 l WELL SURVEY DATA WELL DEPTH TO FLOW SURFACE NUMBER LOCATION DIAMETER DEPTH WATER RATE ELEVATION REMARKS (From Fig. 28-1) 1 Elmore Stinson 133' Residence (Relocated) 33" Into 825 Jack Robins, Driller Hager Ferry Road Rock 2 Halter Johnson Residence Hager Ferry Road 3" 80' 4gpm 825 McCall Gros., Drillers 3 J. Waller Reside..ce Twin Coves 5" 150' 10 gpm 775 McCall Bros., Drillers 4 Mr. William i Van Every Twin Coves 6-1/4 100' 5 gpm 775 McCail Bros., Drillers 5 Harold Junker 790 John Venokal Driller Twin Coves 6 Mr. Wilhelm Paul Stewart, Driller Present Well Have Been Residence Twin Coves 6" 325 18' 1-1/2 gpm 780 Ory Twice 7 Mr. M. J. Groves 90' Cotton Baker, Driller Residence 60' Into 15' To This Well is Not Being Used Twin Coves 2" Rock 20' 10 gpm 770 At Present Due to Mud & Sand in Water 8 Mr. M. J. Groves Twin Coves 2" 80' 10' 5 gpm 770 Cotton Driller m

TABLE 28-1 (Continued) ~3. r-- WELL SURVEY DATA WELL DEPTH TO FLOW SURFACE NUMBER LOCATTON DIAMETER DEPTH WATER RATE ELEVATION REMARKS (From Fig. 28-il 9 Mr. Earnhardt's Boatdock Twin Coves 2" 124 3 gpm 765 10 Kenneth Hastings Residence 810 N. C. 71 11 Mr. Williams Residence 775 N. C. 73 12 Mr. Hubbard Residence 780 Cotton Baker, Driller-N. C. 73 13 Mr. McAllister Residence 770 Cotton Baker, Driller N. C. 73

• Data Not Available

I ).. I TABLE 28-2 /

== ROCK PERMEABILITY TEST RESULTS H0LE DEPTH OF TEST k (ft/yr) h NUMBER SECTION (ft) h(ft) Q(apm) (from Fig. 20-2) H-8 40.0 - 46.15 151.8 1.80 84.3 H-8 61.0 - 67.15 195.7 4.10 148.0 H-68 59.0 - 65.15 191.2 0.00 0.0 H-5 82.4 - 92.0 203.0 0.40 10.0 H-14 115.4 - 169.5 257.0 5.50 26.7 H-14 110.4 - 169.5 239.0 5.50 26.9 H-14 95.0 - 169.5 243.0 2.70 10.6 H-69 65.0 - 71.15 187.0 0.00 0.0 H-43 63.0 - 69.15 182.0 'S 13.6 H-43 77.0 - 82.3 221.0 c.03 1.1 H-13 95.0 - 101.15 255.0 0.00 0.0 H-13 75.0 - 81.1 209.0 0.60 2.0 H-20 60.0 - 66.1 164.0 0.00

0. 0 H-20 36.0 - 42.1 115.0 2.00 160.0 H-58 90.0 - 104.5 244.0 0.00 0.0 h = Applied Water Pressure Head in Feet Q = Flow Rate in Galion: Per Minute k = Horizontal Penaeability in Feet Per Year h

k TABLE 28-) SOIL PERMEABTLITY TEST RESULTS HOLE DEPTH OF TEST k (f yr) -NUMBER SECTION (ft) h(ft) Q(apm) h (From Fig. 20-2) H-32 33.5 - 38.5 11.17 .30 205 H-18 41.5 - 46.5 20.20 .73 274 H-21 16.0 - 21.0 13.00 .56 328 H-5 56.0 - 66.0 3.80 .01 15 W-8 (H-55) 34.0 - 39.0 17.00 .73 328 h = Constant Applied Water Head Above Static Water Tat,le c Q = flow Rate in Gallong Per Minute k = Horizontal Permeability in Feet Per Year h

TABLE 2B-4 RESULTS OF PHYSICAL AND CHEMICAL TESTS ON GROUNSWATER WELL NUMBER: 1 7 11 10-3 2 (From Fig. 2B-1) pH VALUE 8.3 8.3 8.3 8.4 8.1 8.2 TOTAL DISSOLVED Parts Per Million SOLIDS 66 39 55 47 203 86 TOTAL ALKALINITY AS CACO 3 Carbonate 0 0 0 0 0 0 Bicarbonate 38 21 30 23 126 47 TOTAL HARONESS AS CACO 27 18 25 15 41 40 3 SILICA 1.30 0.75 0.73 0.74 1.12 0.71 IRON 0.10 0.10 0.10 0.20 0.50 0.15 ] CALCIUM 7.50 3.20 4.60 3.20 8.60 8.90 MAGNESIUM 1.90 2.40 3.20 1.70 4.80 4.30 CHLORIDES 11.20 14.90 11.20 11.20 26.10 18.70 SULFATES 26 7 10 8 20 12 SPECIFIC CONDUC-TANCE (MICROMHOS) 14250 8500 12000 10500 43000 19000 TURBIDITY, ppm 6 5 3 2 12 11 CATION EXCHANGE CAPACITY OF SOILS EXPRESSED AS MILLEQUIVALENT WEIGHT PER 100 GRAMS SOIL (a) BORING DEPTH NUMBER (FEET) CESIUM STRONTIUM (From Figure 20-2) H-41 16 0.522 0.410 26 0.350 0.230 36 0.338 0.223 47 0.761 0.502 56 0.780 0.514

DRAF TABLE 2B-4'(Continued) CATION EXCHANGE CAPACITY OF S0ILS EXPRESSED AS MILLEQUIVALENT WEIGHT PER 100 GRAMS,50IL'(a) BORING DEPTH NUM8ER (FEET) CESIUM STRONTIUM (From Figure 20-2) H-49 6 0.732 0.483 16 0.532 0.351 26 0.523 0.345 36 0.500-0.330 51 0.542. -0.357 a) Mi11 equivalent Weight - one of the comparative weights of different compounds, elements, or radicals (in this case the elements cesium and strontium) which possess the same chemical value for reaction when compared by reference to the same standard (in this case chlorine).

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DRAFT 4 ~ Plant Structure g 800 Dike El. 7807 {YardEl.760 Lake g Normdng j ~ 4 -l [L Va te r y, SNC \\ %S Ya rd E l. 7f+7 t4'%__. ___ {s ^ 750 - / I / - \\ 8 _// g \\ L J 700 - I e Hard Rock 4 i GfS 650 - 60 Section A-A gg (See Figure 28-2) - Feb. 1970 - I c3 o -n C E 2800 400 800 1200 1600 2000 240;) 23% 600 - I 5*o o to Z :o C O OIStance, feet i $O h 'b m k > a 2 me m =4 m I i sd 1 2 E B i

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• Earth Manual. USDI a

Kh* _O_ 103 L_ 2 iH r Bureau of RecIamatIon, Double packers inflated by pressu.e f rom e nitrogen tank pg. 544 K =hori zontal pe rmeabI li ty, f */yr. whe re : h pg were used to seat off the sectlon of rock within the NX drill N tes to be tested. An occasional single packer test @ constant rate of How intc hole was performed with the test ssction being the length of gpm X 7. M X M

• f tNyr drill hole below the single packer.

WATER METER r-radius of WATER SWlVEL CUT-OFF M n Water pressure was applied to the test section by means of a Homelite centri fugal pump pumping clean lake water f rom test hole, f t y, the supply tank through I" brass pipe and I" rubber hose 9F LINE ~q through the A drill rod to the 3/4" $ srforated pipe sealed PROJECTION between the packers. A surge tank, water meter (city water BY-PASS WATER ~' ~ department meter accurate to 0.3 gal), and pressure gauge VALVE SUPPLY (200 psi.with 5 pal increaants), quick acting cut-off valve; GROUND and try pass valve were In the line between the pump and the SURFACE A drill rod. A DRILL w R03 9 DRILL HOLE / -[suRCE TANK Upon moving the rig to a designated drill hole tbe groundwater level and temperature were determined. The groundwater tem- {

• AIR Lgut

/ perature was in all cases lower than that of the lake water ADtPTER ( used as the test water. The drill hole was then cased with 3/ga plpg steel NX casing to the top of rocit and the entire drill 70 "A p' BJED MVE ~ hole flushed with clean water until the return became clear. 203 The packers were then lowered Inte, the drill hole for testing of the deepest rock section. The height from ground surface TOP INFLATABLg PUMP P to the_ top of the swivel connectlng the A drlll rod and the i metering section was seasured and recorded. The drill hole p) was flushed untll all entrapped alr was removed at which b-NITR0tfM TAMR time the pump was cut baca and the packers inflated to be-s, tween 60 and 80 pst depending on test section depth. The pump was then speeded up and regulated in unl on with the - PERFORATED 3/4" by pass valve until the desired test pressure was reached M 5 Pgpg (I psi per foot of depth below ground surface to middle l* Q of test section). The test pressure was maintained constant <F and the flow in gallons was recorded at I minute intervals I' for 15 to 20 minutes. ..- -. LOWER INFLATAeLE PACKER At completion of the test the quick actlng cut-of f valve was closed and pressure and time readings were recorded for e, LAW ENGINEERING TESTING CO. the closed system. These readings were designated as I;oldtr9 CHARLOTTE. NORTH CAROLINA j test readings. Af ter performing the holding test, the packers were deflated WE M8 CNW and the packer assembly moved up the drif t hole to the neat Mc GUIRE NUCLEAR STATION test teveLThe drill bole was flushed again to remove air In the line and the packers re-Inflated for the nemt test. Sr HEasATIC OF EQulPMEast LAVOUT Ib OCSCRFTION OF PROCEDURE FOR ROOT PERMEABauTY TESTING DWN. SY JAH SCALE: CKD.3Y SEB DC. WING NO. A PpR'D. ISEB ricunt 28-s

p CONTROL VALVE q r., _ l i ,M, j, WATER HETER d WATER SUPPLY GROUND SURFACE // / / %% \\ % //// //// %%%* f/// %%%% //// //// \\\\%% //// In (L+/l+(L/0)A), fps h

• K=

q h 2frLh D t c i P. V. C. PIPE K = horizontal erreabili ty, fps h X 31.5 X 10 = ft/yr q= flow into hole, cfs L= Length of test section D= Internal diameter of test DRILL HOLE WALL section=0 33 f t for wash bored hole at McGuire 1 and 2 h = head of water, f t. e 1 BACKFILL

• Cedergren, H. R., Seepag,0rainage and Flow Ne:s, John Wiley & Sons, 9

i GROUT SEAL Inc., N. Y., 1967, pp. 87-89 fi, 3 %': DENTSHITE SEAL i

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?,.g. yf : CLEAN CRUSHED GRAVEL ,i- -}'.: $5':(.1 SLOTTED P. V. C. PIPE (1 SLOT PER lilCH) ,y ' ~

• .j sj-

~ l 7 0"< CAP aoil Permeability Testing Constant head testing was performed 1.1 piezometers due to the inability of obtaining a good seal in the soll with the packer equipment. A five foot section of slotted (one slot per inch on two sides) p.V.c. pipe was sealed wi thin the soil stratum to be tested. The grcundwater level was recorded to establish the head applied during the test. The water head was maintained at the top of the p.v.c. pipe above ground level by ad-f Justing a needle valve connected in line with a water meter and the water supply tank. Water metcr and time readings were recorded during the test. CCHCt.t ATIC OF EQUIPMENT LAYOUT E 'h LAW ENGINEER!NG TESTING CO. DESCRIPTION OF PROCEDURE FOR / CH ARLOTTE. NORTH CAROLINA ?.0't Ptn.'AEA OillTY TES TING 1 ~ A >,*c Adm McGUiRI: NUCL EAR STATION $1 FIGURE 2B-6

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lp[ h., pase w 0 J extending southward. The Building floor is at two levels; the lower northern finished flow vel is at elevation 739.0 while the upper southern finished floor level u at elevation 760.5. The original ground surface within the building area sloped from about elevation 774 in the north to elevation 748 in the south. Compacted soil fill, up to 12 feet thick, underlies the southern portion of the building, which is supported on end-bearing caissons. The Administration Building is not nuclear safety related. This is a two-story office structure, located south of the Service Building. The building has a finished floor level ct elevation 748.0. The original ground surface within the building area varied from about elevation 733 to 749. Thus, the building is underlain by compacted soil fill up to 14 feet deep and supported on spread footings with a slab on grade. 5 GENERAL DESIGN AND CONSTRUCTION 5.1 UPLIFT ANCHORAGE The existing pre-construction water table at elevation 750 required either an uplift anchorage system to prevent flotation or a permanent substructure drainage system. For the uplif t anchorage system design criteria, a groundwater level at eleva-tion 760 was recommended due to the direct influence of the near-by lake on the water table. Also, for structures bearing on sound rock, the uplift force on the concrete at the interface would be computed as the water pressure multi-plied by 75 percent of the contact area. This is conservative since the remainder bridges over fractures, etc., where the water pressure can act. For structures bearing on materials other than sound rock, the full contact area would be used for uplift computations. Ipyri D-pDL)e to the mag itud of t e b yanc forc for e de gn wa r ta ee v to g"" of 76, c si rabl ho -do for e wo dh e be n req red rt u i anch r s ste. T al rna per anen un rdrai syst was th efo e, bNe]. ado ted and ou ift anch rage yste wa actu ly u d. T e su str et rej [ye-dr in es tem 's ( esig d) t rem ve the ma mum timat d gr nd at foow b ow the oun tio, co inuo sly req; ire. 5.1.1 PERMANENT GROUNDWATER ORAINAGE Site preconstruction groundwater levels were above the substructure level in the Reactor and Auxiliary Building Areas. After construction permanent under-drain and exterior wall drain systems will maintain the groundwater at or near the base of the mat. The underdrain and exterior wall drain systems are described in more detail in FSAR Section 2.4.13.5. A basis for the drainage system is the calculated seepage flow into the Reactor Building foundation area. This calculation was based on the assumptions that Lake Norman serves as a line source, that the excavation functions as a well with a 400 foot diameter, that an impervious lower boundary to the aquifier exists at elevation 712 feet and that the permeability of the material above elevation 712 is 300 feet per year. The equation which is applicable to this situation is7 20-14 12/83

r,'n 2 M ~~ 'M % ", n v V j k 'N. h 0 L k' INSERT D Due to the magnitude of the buoyancy force for a design water table elevation of 760 MSL, considerable hold down force is required for the uplift anchorage system of the Reactor a'nd Auxiliary Buildings. The Diesel Generator Buildings are structurally designed for a groundwater level of 760 Feet MSL. A permanent underground drainage system exists to maintain the water table below 760 Feet MSL. However, in case of blocked drains, the foundations of the Reactor Buildings are anchored into the subsurface rock. This uplift anchorage system is designed to resist the buoyancy force due to groundwater at an elevation of 760 Feet MSL along with a combination of other loads described in the McGuire FSAR, subsection 3.8.1. No anchorage system exists for the Auxiliary Buildings; however, as stated in McGuire Technical Specification 3/4.7.13, Groundwater Monitoring, plant shutdown will occur before uplift and overturning becomes a problem. l 1 l l i l

O us .m Q = ilk (H2-h 2)/1n(2L/r ) g y where Q = seepage rate into excavation K = permeability H = head from bottom of excavation to water surface in Lake Norman = 760 feet (Lake Norman full pond elevation) minus 712 feet (bottom of excavation) h" = head from bottom of excavation to groundwater elevation at the excavation (conservatively estimated to be zero feet) L = distance from center of well to Lake Norman (estimated to be 300 feet) r,= radius of hypothetical well located at excavation Use of the above values and equation yields a calculated flow of about 28 gpm. The actual capacity of the drainage system is several multiples times the calculated inflow of 28 gpm. Initial discharge rates from the dewatering system used at the excavation durir.g construction were approximately 25 gpm. Subsequent flows into the Auxiliary Building sumps during construction have been measured at 3 to 8 gpm (total for the three sumps).

5. 2 EARTH PRESSURES Due to the relative rigidity of the subsurface wall in the Reactor Buildings, earth pressure for at-rest conditions w: used for wall Jesign. For walls that are free to deflect or rotate enough to.svelop the active earth pressure condition, active earth pressure distributions were used.

Detailed recommenda-tions for the distribution and magnitude of the earth pressures are shown on Figure 2D-20. No credit was taken for the action of any passive earth pres-sures in design calculations. The at-rest earth pressure was assumed as the maximum earth pressure acting on the structures, including those during earthquakes. 5.3 DEWATERING All excavations from about elevation 735 to 750 in the Plant Area required dewatering prior to and during the construction period (see Appendix Figure 28-2). The elevation of dewatering varied with the final foundation elevations. The soils requiring dewatering are generally sandy micaceous non plastic silts having a Unified Soil Classification ML-MH and silty sands having a Unified Soil Classification SM. These soils were dewatered by gravity drainage where time and space permitted, and well points were used where necessary. 7Leonards, G. A. (Ed.), Foundation Engineering, McGraw-Hill, New York, 1962, Chapter 3. 20-15 12/83

} F "I" wj u $r i a u 1 The potential for degradation of foundation soils due to excavation is minimal. The foundation of the SNSW Pond Dam was the only Category 1 structure where the foundation excavation extended in saprolites below the water table. The possibility was recognized of degradation by improperly controlled groundwater flowing upward through the soils. The precautionary measures applied to eliminate the degradation at the SNSW Pond foundation was to shape and slope the excavation bottom to allow drainage and by excavating shallow sumps on the excavation perimeter and in low areas. This dewatering did not degrade the foundation soils, as determined by penetrometer testing in the foundation bottom (see Appendix 2G, Section 2G.4, and Attachment 2G-8). For plant foundations on the rock, excavation, above or below the groundwater, did not degrade the foundation materials. Dewatering was done by sumps to remove the nominal seepage that entered the foundation excavation through the natural rock joints.

5. 4 EXCAVATION SLOPES The long term excavation slopes in soil were no steeper than 1 horizontal to 1 vertical.

For grassing and slope maintenance, flatter slopes of 1.5 horizontal to 1.0 vertical were used. During initial dewatering in cuts where seepage forces act, the slopes were no steeper than 1.5 horizontal to 1 vertical unless prior unwatering by well points had been accomplished. In dewatered areas, temporary vertical cuts 15 feet deep were made, unless joint patterns in the residual soil-saprolite had an unfavorable orientation with respect to the excavation plane. Temporary slopes in hard rock were essentially vertical. Temporary slopes in more fractured and weathered rock were flatter. There were no long term excavation slopes in rock. 6 CONCLUSIONS Rock foundations, for the major nuclear-safety related structures at this site, provide negligible settlement with no adverse response to seismic activity. Some nuclear-safety related structures such as storage tanks are supported on the residual soils or on carefully compacted fili. These soils are considered stable against liquefication behavior during any seismic activity. 2D-16 12/83

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7.6.10.2.2.2 Quality of Components and Modules

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{ The Quality Assurance Program is described in Chapter 17. This program has established requirements for design review procurement, inspection, and testing to ensure that system components are of a quality (.onsistent with j minimum maintenance requirements and low failure rates. 7.6.10.2.2.3 Equipment Qualifications System instrumentation and controls _ meet the equipment requirements as I described in Sections 3.10 and 3.11. 7.6.10.2.2.4 Channel Integrity The CRA HVAC system will maintain its functional integrity within the environmental boundaries established in Subdivision 3.11.4 and Section 6.4. 7.6.10.2.2.5 Channel Independence Channel independence is achieved by physical and electrical separation as described in Subdivision 7.6.10.2.2.1. 7,6.10.2.2.6 Control and Protection System Interaction Isolation relays are provided for separation between the ESFAS and control These system where ESFAS signals are used as part of the control system. isolation devices meet all requirements previously stated Subdivision 7.6.10.2.2. 7.6.10.2.2.7 Derivation of System Inputs System inputs are derived from signals that are direct measures of the desired variables. 7.6.10.2.2.8 Operating Bypasses Refer to Section 7.6.10.13 for a description of bypasses. 7.6.10.2.3 Other Appropriate Liandards and Criteria The identification and extent of applicability of other appropriate standards and criteria is presented in Subdivision 7.1.2. 7.6.10.2.4 Failure Mode and Effects Analysis See Table 6.4.3-1. 7.6.11 GROUN0 WATER ORAINAGE SYSTEM The Groundwater Drainage System is described in Subdivision 2.4.13.5 and Subdivision 9.5.8. Physical layout and instrumentation are shown in Figures 2.4.13-1 and 9.5.8-1 respectively. The instrumentation and controls associated with the system include redundant sump level measurements and fully automatic controls for the redundant Safety Class 3 pumps. 7.6-30

l l o ) l no u, 7.6.11.1 Description 7.6.11.1.1 Initiating Circuits U ~ Pump operation and remote high level alarms are initiated by the redundant level instrumentation provided in the sump. 7.6.11.1.2 Logic For each of the three sumps, a lead-lag pump control system is used which provides automatic response to sump level signals. In sumps A, B and C, the lead pump is started at the normal high level and the backup pump is started at the normal high-high level. Operating pumps are stopped at the normal low level. The following alarms are provided in the Control Room: a) Failure of either pump to start at the proper level in sumps A, B, or C. b) High water level and high-high water level in sumps A, B, and C. c) Pump motor overloads. 7.6.11.1.3 Bypasses Each sump pump is controlled by an auto-manual-off switch. When a switch is in the off position, the condition is indicated on the control room Bypassed and Inoperable System Status Panel. 7.6.11.1.4 Interlocks There are no permissive interlocks capable of blocking actuation of either the pumps or of the remote level alarms. 7.6.11.1.5 Redundancy The sump pumps provided for the system are Safety Class 3 and, along with their respective level instrumentation and controls, are fully redundant. Components and equipment associated with one safety class train are physically and electrically separated from and independent of the redundant train in all respects. 7.6.11.1.6 Diversity As noted in Subdivision 7.6.11.2.2, this system has no protection functions. The instrumentation provided, while redundant is not diverse. 7.6.11.1.7 Actuated Devices The level instrumentation actuates the sump pumps and remote high water level alarms. 7.6-31 12/87

h wd w w"**f, n8 hh 7.6.11.1.8 Supporting Systems The system receives electrical power from the Essential Auxiliary Power System which is described in Section 8.3. 7.6.11.1.9 Design Basis Information 7.6.11.1.9.1 Design Basis The instrumentation and controls provided are designed to provide' reliable indication of s level and continuous automatic control of pump operation to s maintain watt evels within the design limits. 7.6.11.1.9.2 Conformance with IEEE 279-1971 (By Section 3 Item Number) (1) The generating station conditions requiring action by this system are sump water levels in excess of the design levels. For sumps A, 8, and C, levels in excess of high level require the lead pump to run and remote alarm indication of high water levels. Levels in excess of high-high level require the backup pump to run and remote alarm indication of high-high water levels. (2) The monitored generating station variable is sump water level. (3) Two independent channels of level instrumentation are provided..The instrumentation and associated alarm and control channels are physically separated and fully redundant. (4) Locations of sump water level switches are shown in Figure 9.5.8-1. Alarm is activated on high-high level. (5) In Conformance. I (6) Levels requiring action are given in (1) above. (7) Information concerning the energy supply is presented in Section 8.1.4 and 8.3.1. Environmental considerations are described in Table 3.2.3-1. (8) Structures and equipment associated with this system are seismic Category 1 and as such are designed to withstand events and environmental conditions are described in Section 3. (9) Minimum system performance requirements are discussed in Subdivision 2.4.13.5. System instrumentation accuracies of 0.25 feet are satisfactory for alarm and control purposes. 7.6.11.2 Analysis 7.6.11.2.1 Conformance With NRC General Design Criteria 7.6-32 12/87 1

DRAFT ~ There are no specific General Design Criteria applicable to this system. 7.6.11.2.2 Conformance With IEEE 279-1971, Section 4 (By Item Number) This sytem has no protective functions as defined in IEEE 279-1971. The extent to which the design of this sytem satisfies the requirements of this Standard is described below. 4.1 THe instrumentation and controls associated with this system are designed to initiate the appropriate action automatically and reliably at the design levels. 4.2 The instrumentation and controls associated with this system meet the Single Failure Criterion. The two trains of equipment provided are fully redundant and are electrically independent of each other. 4.3 Instrumentation and control components used with the system are of established quality. 4.5 Instrumentation and controls associated with the system are designed to maintain channel integrity under design basis conditions. 4.6 The redundant instrumentation and control channels are completely independent of and are physically separated from each other 4.10 Capability for testing and calibrating instrumentation channels is provided. 7.6.12 OIESEL GENERATOR FUEL OIL SYSTEM 7.6.12.1

System Description

The Diesel Generator Fuel Oil System is discussed in Subdivision 9.5.4.2. Alarms are provided locally for a low level condition in the diesel fuel oil storage tank and for high and low level in the fuel oil day tank. A local and Operator Aid Computer (OAC) alarm is provided for low fuel oil pressure to the engine. The operator is alerted to these conditions by a common alarm in the Control Room in sufficient time to take the appropriate corrective action. The fuel oil transfer pump is automatically actuated by a low level in the diesel fuel oil day tank. The fuel oil booster pump is automatically started with the diesel engine by the diesel start circuit. The pump runs until adequate fuel oil pressure is provided by the engine driven fuel oil pump at which time the booster pump is deenergized by a pressure switch sensing the fuel oil supply pressure. 7.6.12.1.1 Design Basis Information The design basis for the fuel oil system instrumentation is to control and monitor the operation of the fuel oil system so that the diesel generator can function properly under accident conditions and during testing. This system has no protective function as defined in Section 2 of IEEE 279-1971.

However, 7.6-33 12/87

9.5.7.3 Safety Evaluation - k g The. Diesel Generator Lubricating 011 System for each diesel unit is a Duke Class C System. Each diesel unit is housed separately in Category 1 structures which are part of the Auxiliary Building. Internal missiles, if generated, could only affect one diesel, since each is contained in its own. room. Since the diesel units themselves are fully independent and redundant for each nuclear unit, they meet.the single failure criterion. 9.5.7.4 Tests and Inspections System components and piping are tested to pressures designated by appropriate codes. Functional tests are performed before initial operation. Regularly scheduled diesel operation demonstrates the operational readiness of the Diesel Generator Lubricating Oil System. 9.5.7.5 Instrumentation Application Refer to Subsection 7.6.15 for a discussion of the Diesel Generator Lubricating Oil System Instrumentation. 9.5.8 GROUN0 WATER DRAINAGE SYSTEM 9.5.8.1 Desian Basis The Groundwater Drainage System is designed to relieve hydrostatic pressure from the Reactor and Auxiliary Buildings by discharging groundwater collected in sumps to either the yard drains or the Turbine Building sumps. The Ground-water Drainage System is a shared system with three sumps in the Auxiliary Building. 9.5.8.2

System Description

The Groundwater Orainage System is shown on Figure 9.5.8-1. Six groundwater sump pumps draw collected groundwater seepage through their pump strainers from three sump locations in the Auxiliary Building. Each sump contains two 100 percent capacity pumps (250 GPM each) one aligned to train A and the other to train B. The groundwater for sump C is pumped to the plant yard drains. Sumps A and B also collect small quantities of non-radioactive drains as shown on Figure 9.5.8-1. The water from these sources is in such low quantities that the safety function of this system is not jeopardized. The sump pumps for sump A and B discharge to the Turbine Building sumps to enable monitoring of the liquid and conventional processing. The underdrainage grid drains to the groundwater drainage sumps as described in section 2.4.13.5. Each sump is isolated by its respective check valve which is provided to prevent reverse flow into the sumps. l l 9.5-20 12/83

byjlg/'"4% pj" t WR es l gj g 9.5.8.3 Safety Evaluation This system is safety related because it protects a Category 1 seismic struc-Therefore, the groundwater sump pumps and their associated discharge l ture. . valves are classified Safety Class 3 denoted in Table 3.2.2-2. 9.5.8.4 Tests and Inspections System components and piping are tested to pressures designated by appropriate Functional tests are performed before initial operation. Each sumps codes. groundwater is sampled periodically to insure that only groundwater is seeping into sumps and not radioactive water or contaminants. 9.5.8.5 Instrumentation Application A level switch in each sump starts the respective groundwater drainage sump A computer alarm also is initiated upon high level. The pump A on high level. level switch stops the respective groundwater sump pump A on low level. Another level switch in each sump starts the respective groundwater drainage sump pump B on high-high level. An annunciator alarm is initiated upon high-high. level. The level switch stops the respective groundwater sump pump B on low level. Refer to Subsection 7.6.11 for additional discussion of the Groundwater Drain-age System instrumentation. 9.5.9 OIESEL GENERATOR CRANKCASE VACUUM SYSTEM 9.5.9.1 Design Bases The Diesel Generator Crankcase Vacuum System is designed to reduce the possi-bility of building up a concentration of combustible gases in the crankcase. 9.5.9.2

System Description

The Diesel Generator Crankcase Vacuum System for each diesel unit consists of a vacuum blower and an oil separator. The crankcase vacuum blower is connected to the crankcase by means of a vent line. A variable orifice in the vent line controls the amount of vacuum and an oil separator in the vent line prevents drawing an excessive amount of lubricating oil from the crankcase. A drain line from the separator returns oil to the engine (see figure 9.5.9-1). 9.5.9.3 Safety Evaluation The Diesel Generator Crankcase Vacuum Systems' components, valves and piping are seismically qualified and built to applicable codes where possible. Each diesel unit is housed separately in a Category 1 structure which is part of the Auxiliary Building. Internal missiles, if generated, could only affect one diesel, since each is contained in a separate room. The diesel units them-selves are fully independent and redundant for each nuclear unit; thus, they meet the single failure criterion. 9.5-21 12/83

~ Attachment Two Draft Selected Licensee Commitment 16.9-8 Groundwater Level Monitoring System

D \\ A AMEEBEEE EIE W 16.9 AUXILIARY SYSTEMS 16.9-8 GROUNDWATER LEVEL MONITORING SYSTEM COMMITMENT a. The groundwater level monitors listed in Table 16.9-4 for the Reactor and Diesel Generator Buildings shall be operable. b. The groundwater level for the Reactor and Diesel Generator Buildings shall be maintained below elevation 731' mean sea level (usi). APPLICABILITY: At all times. REMEDIAL ACTION: For Units 1 and 2 a. 1) With one or more of the Groundwater Monitors listed in Table 16.9-4 inoperable, restore the inoperable monitor (s) to operable status within 7 days or provide an alternate method of determining the groundwater level for that monitored area (s). 2) If the inoperable monitor (s) are not returned to operable status within 7 days, submit a special report to the NRC within 30 days documenting the results of the investigation of the inoperable monitor (s). b. 1) With groundwater level for the Reactor anJ/or Diesel Generator Buildings above the Alert level for a period of 7 days, initiate a Design Engineering evaluation to determine the cause, and to pivvide corrective actions. 2) If the level is not restored to below the Alert level within 7 days, submit a special report to the NRC within 30 days documenting the results of the investigation of the incrc* ed groundwater level. TESTING REQUIREMENT. a. Each groundwater level monitor instrument / loop for locations listed in Table 16.9-4 shall be demonstrated operable at least once per 18 months by the performance of a loop calibration and operational test. 16.9-14

s. W r DR r A TESTING PROCEDURES? 1. IP/0/B/3050/26 Groundwater Level Loop Calibration 2. IP/0/B/3204/04 Calibration Procedure for ITT.Barton Model 273A Differential Pressure Transmitter 3. IP/0/A/3250/08 Calibration Procedure for Hays Republic V-5A Indicators 4. IP/0/B/3250/08 Calibration Procedure for Rays Republic V-5A Indicators 5. IP/0/A/3250/13B Calibration Procedure for Custom Components Pressure Switch Model 6832G1. 6. IP/0/E/3250/13C Calibration Procedure for Custom Components Pressure Switch Model 6862G1. 7. IP/0/B/3250/27 Calibration Procedure for Gems XM800 Level Transmitters

REFERENCES:

1. McGuire FSAR, Chapter 2.4.13 2. McGuire FSAR, Appendix 2B t 3. McCnire FSAR, Chapter 9.5.8 4. FeGuire FSAR, Appendix 2D, Chapter 5.1.1 5. McGuire FSAR, Chapter 7.6.11 6. McGuire Figure 2.4.13-1 7. OP/1/A/6100/10I, Annunciator Response for Panel IAD l 16.9-15

D A'e f TABLE 16.9-4 I GROUNDWATER LEVEL MONITORS LOCATION EXTERIOR / INTERIOR APPLICABILITY REACTOR BUILDING EXTERIOR UNIT 1 AA-40, ELEV. 736' INTERIOR UNIT 1 DD-42, ELEV. 736' INTERIOR UNIT 1 REACTOR BUILDING - EXTERIOR UNIT 2 BB-72. ELEV. 736' INTERIOR UNIT 2 DD-69, ELEV. 736' INTERIOR UNIT 2 d I I SEL/274/ bhp j d 16.9-16 I l ,ry-, ,,---..,gg ,99w-- -my,,,7,y,_,mp-7 ,,,,-_g,- ,%_.m.,.,,_m,ps. ,py y.,9, ge., g3 ,y-----9--,-_. v- ,-----.y e y y _.m

Attachment Three McGuire Nuclear Station Groundwater Level Loop Calibration Procedute

O FOR YOUR Duke Power Company (1)l0 No IP/0/B/3050/26 0 to NFORMATiON PROCEDURE PROCESS RECORD Cnange(s)9 incorporated h PREPARATION (2) Staten MCGUIRE NUCLEAR STATION (3) Procedure Title CROUNDWATER LEVEL LOOP CALIBRATION W) Prepared By *

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Date 7, V,/98 b WL Date f-II~ (5) Reve6ed By ' Cross-Discip ary e By N/R (6) Temporary Approval (if necessary) By (SRO) Date b Date i By r W/ !M Date (7) Approved By _ '/ (/ / / (8) Misceflaneous v Renewed /Appued By Date Reveaed/Appnad By Date (9) Comments (For procedure reissue indicate whether additional changes, other than prevously approved changes, are in-cluded. Attach additonal pages,if necessary.) Additional Changes included. 3 Yes O No (10) Compared with Control Copy Date (11) Requires change to FSAA not identified in 10CFR50.59 evaluation? O Yes KNo if "yes', attach detailed explanaton. ' o,7 I b' I) llq Completion (12) Date(s) Performed (13) Procedure Completon Venfication O Yes O N/A Check Ests and/or blanks property vvtialed, signed, dated or filled in N/A or N/R, as appropnate? O Yes O N/A UGd enclosures attached? O Yes O N/A Data sheets attached, completed, dated and signed? O Yes O N/A Charts, graphs, etc. attached and property dated, k1entified and marked ? O Yes O N/A Procedurt requrements met? Venfied By . Date (14) Procedure Completion Apprted Gate (15) Remarks (s"ach additionalpages, if necessgyl <, Q * ;, ' .}}