ML15062A030

Comanche Peak Nuclear Power Plant - Work Plan for Completing a Once Through Cooling Water Study for Total Dissolved Solids, Chlorides, and Sulfates

ML15062A030
Person / Time
Site:	Comanche Peak
Issue date:	02/25/2015
From:	CH2M Hill
To:	Luminant Generation Co, Office of Nuclear Reactor Regulation
Shared Package
ML15062A029	List: ML15062A028 ML15062A030
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Download: ML15062A030 (11)

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Work Plan for Completing aOnce Through Cooling Water Study forTotal Dissolved Solids, Chlorides, and SulfatesLuminantComanche Peak Nuclear Power PlantSegment 1229 of the Brazos River BasinSomervell County, TexasPrepared forLuminant Generation Company LLCTPDES Permit No. WQ0001854000Dallas, TexasFebruary 2015CH2MHILL.Prepared by12750 Merit DriveSuite 1100Dallas, TX 75251 Acronym s and Abbreviations ................................................................................................................................ iiS Introduction ............................................................................................................................................ 1-11.1 Background ......................................................................................................................................... 1-11.2 Project O bjectives .............................................................................................................................. 1-11.3 Project Scope ...................................................................................................................................... 1-21.4 Project Team ...................................................................................................................................... 1-22 Site D escription and Regulatory Status .................................................................................................. 2-12.1 Site D escription .................................................................................................................................. 2-12.2 Regulatory Status ............................................................................................................................... 2-13 Investigation Procedures ........................................................................................................................ 3-13.1 Sam pling Strategy ............................................................................................................................... 3-13.2 D eterm ination of Sam pling Locations ........................................................................................... 3-13.2.1 Proposed Sam pling ............................................................................................................. 3-13.2.2 Proposed Sam pling Schedule ............................................................................................ 3-14 Sam pling Conditions .............................................................................................................................. 4-14.1 Am bient and Background Conditions ............................................................................................ 4-14.2 O perating Conditions ........................................................................................................................ 4-14.3 Sam pling Points and Log Sheets ..................................................................................................... 4-15 D ata Analysis .......................................................................................................................................... 5-15.1 Statistical Analyses ............................................................................................................................. 5-15.1.1 Statistical Approach / D ata Collection ........................................................................... 5-15.1.2 Statistical Test M ethods ..................................................................................................... 5-1Tables3.1 Sam pling Schedule ...................................................................................................................................................................... 3-14.1 Am bient / Background Conditions Log Sheet ...................................................................................................................... 4-24.2 O perating Conditions Log Sheet .............................................................................................................................................. 4-2Figures1.1 Location M ap ............................................................................................................................................................................... 1-22 .1 F acility M ap .................................................................................................................................................................................. 2 -2WTOZ21O151O1QOFW

°CCH2M HILLDHLEPALuminantmg/i,MGDml,NPPOTCWTACTCEQTDSTPDESdegrees CelsiusCH2M HILL Engineers, Inc.DHL Analytical Services, Inc.U.S. Environmental Protection AgencyLuminant Generation Company LLCmilligrams per litermillion gallons per dayMilliliterNuclear Power Plantonce-through cooling waterTexas Administrative CodeTexas Commission on Environmental QualityTotal Dissolved SolidsTexas Pollutant Discharge Elimination SystemVWrr2 1015 102 DFW 1.1 BackgroundLuminant Generation Company LLC (Luminant) has contracted CH2M HILL Engineers, Inc.(CH2M HILL) to provide consulting services for completing a once-through cooling water study at theComanche Peak Nuclear Power Plant (NPP). Chemical analysis will be conducted by an independentlaboratory. This Once-Through Cooling Water Study Plan (Study Plan) was prepared for use duringinvestigation of Total Dissolved Solids (TDS), Chlorides, and Sulfates concentrations of the cooling water atthe facility. This Study Plan specifies sampling points, procedures, data collection, and quality assurancemethods that will be used during sampling activities to assure quality data are obtained.The Comanche Peak NPP is located in Somervell County in north central Texas approximately 4.5 milesnorthwest of the City of Glen Rose, Texas. The location of the Comanche Peak NPP is shown on Figure 1.1.The circulating water streams that are the focus of this study are obtained from Squaw Creek Reservoir,which is adjacent to the power plant.1.2 Project ObjectivesTexas Administrative Code 30 TAC 307.8(d) specifies that water quality-based effluent limits will not berequired when a discharge of once-through cooling water (OTCV) does not "measurably alter" the intakeconcentration. However, to establish whether or not a discharge of OTCW is measurably altered, Procedures toImplement the Texas Surface WaterQua/io, Standardsl requires the statistical analysis of paired samples todetermine if there is a significant difference between the intake and discharge concentrations at the 95%confidence level.The purpose of this study is to determine if there is a statistically significant difference between the TDS,Chloride, and Sulfate concentrations in the circulating water intake and the effluent that would require waterquality-based effluent limits. This Study Plan will focus on methods and procedures that allow accuratequantification of the dissolved minerals concentrations in the cooling water before and after passing throughthe power plant. It will specify the number, type, and locations of samples, along with details of the propersampling techniques and analytical methods. This document will be used by field and laboratory personnel asa guideline for conducting the sampling and analysis.1 Procedures to Implement the Texas Surface Water Quality Standards (RG-194, June 2010).WTOZ1015101ZDFW1-1 INTR~ODUCTIONFIGURE 1.1Location Map1.3 Project ScopeThe tasks required to complete the study are as follows:* Perform water sampling at the intake and discharge of the circulating water system at the Comanche PeakNPP* Analyze the water samples for TDS, Chlorides, and Sulfates* Evaluate the results of the sampling data using statistical analysisThe methods that will be used to complete these tasks are described in the following sections of this StudyPlan.1.4 Project TeamThe project team consists of Luminant, DHL Analytical Services, Inc. (DHL), and CH2M HILL. Luminantwill fund the project, provide input on the study, and collect the samples; DHL will provide the sample kitsand perform the analysis; and CH2M HILL will develop the Study Plan, evaluate the data, complete thestatistical analysis, and develop the final report.WTOZJOIS 51012 DFW 2.1 Site DescriptionThe Comanche Peak NPP and Squaw Creek Reservoir are located in Somervell County in north centralTexas. The power plant consists of two separate generating units, one with a rated capacity of 1084megawatts and one with a rated capacity of ll21megawatts that operates continuously.Squaw Creek Reservoir was constructed as a cooling water reservoir to service the power plant. The surfacearea of the reservoir is approximately 3,275 acres with an average depth of approximately 46 feet. Thereservoir discharges occasionally at the southeast end to Squaw Creek thence to the Paluxy River.The circulating water pumps provide high volumes of cooling water to a large condenser located on eachgenerating unit. Flows from the circulating water system are permitted at 3,168 MGD. Cooling water ispumped from the intake structure located on the north side of the facility, provides cooling for the powerplant main condensers, and is discharged back into Squaw Creek Reservoir through the discharge structurelocated at Outfall 001 on the south side of the facility. Figure 2.1 shows the facility, Squaw Creek Reservoirthe cooling water intake, the discharge structure, Outfall 001, and the proposed sampling locations.2.2 Regulatory StatusTPDES Permit No. WQ0001854000 authorizes discharges of wastewater from the Comanche Peak NPP.The current permit was issued by the Texas Commission on Environmental Quality (TCEQ) on June 26,2012. The permit authorizes discharge of OTCW, auxiliary cooling water, and previously monitored effluentsat Outfall 001.WTOZ 1015 1012 OFVV22-1 SITE DESCRIPTION AND REGULATORY STATUSFIGURE 2.1Facility MapIntake Sample Point/Discharge Sample Point(Outfall 001)WT0210151012DFWJ2-2-2 3.1 Sampling StrategyThe sampling strategy is to collect the necessary water samples from the cooling water intake and dischargeusing proper equipment and procedures to establish the TDS, Chlorides, and Sulfate concentrations of thesestreams. Samples will be representative of normal operating conditions at the power plant.3.2 Determination of Sampling LocationsSampling locations as shown on Figure 2.1 were chosen based on a review of physical features at theComanche NPP.3.2.1 Proposed SamplingThe following samples are proposed for the study:" At the surface of the reservoir at the circulating water intake structures. At least four depth compositeswill be collected at the intake to compare to surface samples. Surface sample results will be used in thestatistical analysis.* At Outfall 001 at the discharge structure to Squaw Creek Reservoir.Analysis will be performed using EPA approved methods as found in 40 CFR Part 136. Specifically, StandardMethod 2540C will be used for TDS with a reporting limit of 50 mg/L, and EPA Method 300 will be usedfor Chloride and Sulfate analysis with reporting limits of 100 mg/L and 30 mg/L, respectively.3.2.2 Proposed Sampling ScheduleGrab samples will be collected every 10 days for at least ten sample events. Each paired sample will beobtained within a one hour period. The plan is to collect the samples ten days apart unless there is asignificant rainfall event in the area. This will provide 10 paired samples, which is the minimum specified inProcedures to Implement the Texas Surface WaterQua/ity Standards. TDS, Chlorides, and Sulfates concentrations willbe measured for the indicated sample points.WT021015 1012 DFW3-3-1 Prior to beginning each sampling round, background data should be collected. This data will include ambientweather conditions, reservoir conditions, and operating conditions of the power plant. This data should berecorded on the appropriate log sheet.4.1 Ambient and Background ConditionsWeather conditions need to be recorded during the sampling activities. For example, actual daily rainfallamounts will be documented. Sampling should be suspended during certain conditions, such asthunderstorms and heavy winds.Field measurements of pH, temperature, and conductivity should be taken at the time of sample collection.During the course of the sampling effort, ambient and background conditions data will be recorded on theAmbient/Background Conditions Log Sheet as shown in Table 4.1.4.2 Operating ConditionsOperating conditions to document include items such as generating capacity, and circulating water flow (ifavailable). Operating condition data will be recorded on the Operating Conditions Log Sheet as shown inTable 4.2.4.3 Sampling Points and Log SheetsThe sampling log sheets will include the following information:" Sample Point ID #* Date and time" Any problems encountered during sampling" Ambient (weather) conditions* Circulating water temperature (inlet and outlet)* Specific conductance (Conductivity)" pH* Unit LoadsWT0210151012DFW 44-1 SAMPLING CONDITIONSTABLE 4.1Ambient I RaoTABLE 4.2Operating Conditions Log Sheet3odne ultUntLa ntLa4ieTm ' WMDat678910WTO210151012DFW'44-2 5.1 Statistical AnalysesThe TCEQ requirement for water quality-based effluent limits of pollutants discharged into OTCW isapplicable unless there is "no measurable increase" in the pollutant concentration of the effluent as comparedto the intake water. The term "no measurable increase" is statistically defined; therefore, it must bedemonstrated by statistical analysis of the sampling data that there is not a statistically significant difference atthe 95% confidence level between the concentrations of TDS, Chlorides, and Sulfates in the intake andeffluent. Only then can the condition for exclusion of OTC\W from water quality-based permit limits besatisfied.5.1.1 Statistical Approach I Data CollectionA statistical analysis of the data will be done to determine if there is "no measurable increase" in the TDS,Chloride, and Sulfate concentrations across the OTCW system of the Comanche Peak NPP.* Ten paired samples will be collected which meets the minimum number of paired samples of 10 asspecified by TCEQ.* Paired samples shall be collected no more than one hour apart.* Paired data (intake and effluent sample concentrations) of TDS, Chlorides, and Sulfates will be used toconduct the statistical analysis.5.1.2 Statistical Test MethodsThe lognormal distribution is usually chosen for environmental data as described in the EPA Technical SupportDocument for Water Quality Based Toxics Control.2The two-tailed Student's t-test will be done on the log mean and log standard deviation of each data set at the95% confidence level to check for significant differences between the effluent data and the intake water data.If the results show the calculated t-statistic (t-Stat) is less than the critical t-statistic (t-Critical two-tail), thenthere is no significant difference between the concentrations of TDS, Chlorides, and Sulfates in the intakeand effluent. However, if the t-Stat is greater than the t-Critical two-tail then there is a statistically significantdifference between the intake and the effluent stream concentrations.Data outliers for each data set will be evaluated using statistical test methods described by the EPA (EPA,1992). In this method a calculated test statistic is compared to a critical value. The datum is an outlier if thecalculated test statistic is greater than the critical value. Any data that are legitimate statistical outliers will beexcluded from the data set.2 Technical Support Document for Water Qualtry Based Toxics Control (FP.\ 505-2-90,-001, March 1991).WrO2 1015101 2DF'W 1