PNNL Darlington Nuclear Power Plant Project Review of Ontario Power Generation s Assessment of Cooling Towers for Condenser Cooling

Transcription

1 PNNL Darlington Nuclear Power Plant Project Review of Ontario Power Generation s Assessment of Cooling Towers for Condenser Cooling February 2011

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3 PNNL Darlington Nuclear Power Plant Project Review of Ontario Power Generation s Assessment of Cooling Towers for Condenser Cooling February 2011 Prepared for Canadian Nuclear Safety Commission under Contract DE-AC05-76RL01830 Pacific Northwest National Laboratory Richland, Washington 99352

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5 Contents 1.0 Introduction Scope Description Alternative Condenser Cooling Technology Report Contents Results and Conclusions Adequacy of the Data Supporting the Evaluation of Alternative for Condenser Cooling Technologies Adequacy of the Data Interpretation Supporting the Evaluation of Alternative Condenser Cooling Technologies Adequacy of the Methodology Supporting the Evaluation of Alternative Condenser Cooling Technologies Overall Adequacy of the use of the Plant Parameter Envelope Overall Adequacy of the OPG Review of Alternative Condenser Cooling Technologies Adequacy of the OPG Review by Environmental Component Atmospheric Environment Surface Water Hydrology Aquatic Ecology Terrestrial Ecology Dose to the Public Land Use Cultural Environment Socioeconomics Human Health and Well Being Costs Approach Analysis of Cooling System Assessment Atmospheric Environment Relevant EIS Guidelines for the Atmospheric Environment Summary of OPG s Assessment of the Atmospheric Environment Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Atmospheric Environment Impacts from Condenser Cooling Alternatives Surface Water Hydrology Relevant EIS Guidelines for Surface Water Hydrology Summary of OPG s Assessment of the Surface Water Hydrology Baseline Conditions and Condenser Cooling Impacts iii

6 4.2.3 Adequacy of OPG s Assessment of Surface Water Hydrology Impacts from Condenser Cooling Alternatives Aquatic Environment Relevant EIS Guidelines for the Aquatic Environment Summary of OPG s Assessment of the Aquatic Environment Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Aquatic Environment Impacts from Condenser Cooling Alternatives Terrestrial Environment Relevant EIS Guidelines for the Terrestrial Environment Summary of OPG s Assessment of the Terrestrial Environment Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of the Terrestrial Environment Impacts from Condenser Cooling Alternatives Dose to the Public Relevant EIS Guidelines for Dose to the Public Summary of OPG s Assessment of Dose to the Public from Release of Radioactive Radioactivity Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Radioactive Impacts from Condenser Cooling Alternatives Land Use Relevant EIS Guidelines for Land Use Summary of OPG s Assessment of Land Use Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of the Land Use Impacts from Condenser Cooling Alternatives Cultural Environment Relevant EIS Guidelines for the Cultural Environment Summary of OPG s Assessment of the Cultural Environment Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Cultural Impacts from Condenser Cooling Alternatives Socioeconomics Relevant EIS Guidelines for Socioeconomics Summary of OPG s Assessment of Socioeconomic Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Socioeconomic Impacts from Condenser Cooling Alternatives Human Health and Well Being Relevant EIS Guidelines for Human Health iv

7 4.9.2 Summary of OPG s Assessment of the Human Health Environment Baseline Conditions and Condenser Cooling Impacts Adequacy of OPG s Assessment of Impacts to Human Health from Condenser Cooling Alternatives Costs Construction Costs Operation and Maintenance Costs Performance Costs/Impacts (on capacity and power generation) Adequacy of OPG s Assessment of Cost from Condenser Cooling Alternatives References Appendix A Review Team Members... A.1 Appendix B Relationship Between the Elements of the Review Performed and the Environmental Components and Valued Ecosystem Components Listed in the EIS Guidelines... B.1 Appendix C Alternative Condenser Cooling Technologies... C.1 Tables 2.1 Summary of the Review of Alternative Cooling Systems Prepared by OPG in Response to IR Nuclear Facilities with Closed-Cycle Cooling Systems on the Great Lakes v

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9 1.0 Introduction The Darlington Joint Review Panel (JRP) is reviewing an Environmental Impact Statement (EIS) submitted by Ontario Power Generation (OPG) for the Darlington New Nuclear Power Plant project (SENES 2009a). OPG has submitted information that has considered various types of condenser cooling water technologies. The EIS and supporting information compare once-through lake water cooling to alternative cooling methods, principally different cooling tower technologies. Based on their analysis of this information, OPG selected once-through lakewater cooling as the preferred cooling design. To supplement the Darlington JRP s reviews of the submissions related to alternative means of condenser cooling, the Canadian Nuclear Safety Commission (CNSC), on behalf of the JRP, asked the Pacific Northwest National Laboratory (PNNL) to perform an independent evaluation of the adequacy of the EIS assessment of cooling towers for condenser cooling. The purpose of PNNL s evaluation is to independently assess the adequacy of the process and information OPG presented to articulate the tradeoffs between various cooling technologies. The PNNL evaluation does not attempt to make a determination of the preferred cooling technologies as that is beyond the scope of this review. In addition, the PNNL evaluation does not assess OPG s once-through cooling submissions for adequacy, but considers them in comparing the level of analysis and amount of information included in the EIS to that used for cooling tower technologies. 1.1 Scope Description PNNL s review focused on the data, data interpretation and methodology OPG presented in the EIS and supporting documents to determine the adequacy of the assessment of cooling towers as the means for condenser cooling. The review includes an assessment of the adequacy of the data, data interpretation and methodology on: Atmospheric environment Releases of cooling towers treatment chemicals into the plume discharge, air quality standards Water deposition, salt deposition Fogging Icing Surface water hydrology Lake circulation Shoreline processes Lake temperature Site drainage and water quality 1.1

10 Aquatic ecology Effects on aquatic biota and habitat from entrainment and impingement during operation of the intake Effects on aquatic biota and habitat from thermal and chemical discharges Terrestrial ecology Vegetation Communities and Species Bird Communities and Species Mammal Communities and Species Insects Amphibians and Reptiles Landscape Connectivity Dose to the public Effects of alternative cooling technologies on dose to the public Malfunctions, accidents and their consequences Relationship between alternative cooling technologies and the impact of malfunctions and accidents Land use Area required for siting of the cooling towers and ancillary services Cultural Effects of alternative cooling technologies on cultural resources Socioeconomics Social factors impacted by cooling towers, such as visual and noise effects Change in community character, reduced enjoyment of private property and recreational facilities Health and well being Effects of alternative cooling technologies on human health and well being Costs Comparison of costs of construction, operation, maintenance and performance of the different cooling tower designs The review was conducted by a team of PNNL subject matter experts (see Appendix A). The PNNL team also considered other relevant topics identified in Guidelines for the Preparation of the Environmental Impact Statement for Ontario Power Generation s Darlington New Nuclear Power Plant Project (CNSC 2009). The table in Appendix B shows how these topics relate to the Environmental Components and Valued Ecosystem Components provided in the EIS Guidelines (CNSC 2009). 1.2

11 PNNL s review focused on documents provided by CNSC or available on the Canadian Environmental Assessment Agency registry. The documents reviewed consisted of relevant portions of the EIS (SENES 2009a), the Normal Heat Sink Cooling System Comparison for the New Nuclear- Darlington Project (MPR 2009) and relevant technical support documents. The team also reviewed the OPG Information Request (IR) responses related to alternative cooling technologies. At times the team s review extended beyond IRs specifically addressing alternative cooling technologies but the team did not review all IR responses on all topics. Malfunctions, Accidents and their Consequences was identified as one of the aspects of review. The PNNL team reviewed the EIS and related documents. The information reviewed by PNNL showed that OPG addressed a wide suite of malfunctions and accidents. OPG did not address whether malfunctions and accidents would have different consequences based on the use of different condenser cooling systems. In PNNL s past experience, accident consequences are not assessed relative to alternative cooling systems; therefore this area was not addressed further and is considered adequate. Several Environmental Components listed in the EIS Guidance were not addressed in the review performed by PNNL. For example, because no withdrawal of groundwater is planned to meet cooling system demands, and blowdown from the considered cooling systems would not be discharged to groundwater, impacts on geology and hydrogeology were not addressed. 1.2 Alternative Condenser Cooling Technology The cooling system options considered for the site were once through lakewater cooling, natural draft cooling towers, fan assisted natural draft cooling towers, mechanical draft cooling towers, hybrid cooling towers (wet/dry), dry cooling towers, and spray/cooling ponds. Hybrid cooling towers (wet/dry), dry cooling towers, and spray/cooling ponds were eliminated from detailed analysis early in the process so the analysis performed and documented in the technical support documents and in the Normal Heat Sink Cooling System Comparison for the New Nuclear - Darlington Project (MPR 2009) were limited to once through lakewater cooling, natural draft cooling towers, fan assisted natural draft cooling towers and mechanical draft cooling towers. Information on hybrid cooling towers was presented in OPG s response to IR 11 (OPG 2010a). Since no reactor design or cooling-tower technology had been selected for the new nuclear power plant at the Darlington site, OPG developed two scenarios documented in the scope of the project technical support document (TSD) (SENES 2009b) and in the surface water assessment TSD (Golder 2009a). One scenario considered a design that was based on a once-through cooling system, with the reactor design that required the largest raw water flow be taken as the upper bounding case for this scenario (SENES 2009b, Golder 2009a). The other scenario combined several cooling tower types using the largest water requirement as the upper bounding case from the reactor design that required the largest raw water flow for this scenario (SENES 2009b). Each scenario was determined by OPG to be bounding for different components (SENES 2009b). One disadvantage of this approach is that the condenser cooling options were not analyzed individually in some areas where one technology is clearly unique. For example the visual effects of mechanical draft cooling towers with plume abatement were not considered, rather the worst case plume from the mechanical draft cooling towers was considered. 1.3

12 The OPG submission Appendix B of the Normal Heat Sink Cooling System Comparison for the New Nuclear - Darlington Project (MPR. 2009) provides a description of the cooling system alternatives that were considered by OPG for the analysis performed to support the Darlington Environmental Impact Statement for new nuclear units at the Darlington site. This PNNL report provides additional description of cooling system alternatives in Appendix C. 1.3 Report Contents Chapter 2 of this document presents the overall results and conclusions of our review. Chapter 3 of this document describes the review approach taken. Chapter 4 of this document provides details of the reviews conducted by our technical experts. Chapter 4 is organized to parallel the organization of technical elements presented in the response to Information Request - IR 11 for the elements considered. Chapter 5 of this document provides references. Appendix A of this document provides a list of the PNNL reviewers. Appendix B of this document provides a table illustrating the relationship between the elements of the review performed and the environmental components and Valued Ecosystem Components listed in the EIS Guidelines Appendix C of this report provides an additional description of cooling system alternatives. 1.4

13 2.0 Results and Conclusions This section summarizes PNNL s assessment of the methodology, data, and data interpretation OPG presented in its EIS and supporting documents to determine the adequacy of the assessment for cooling towers as the means for condenser cooling. The description of adequacy of data assessment is presented first, followed by data interpretation, and then OPG s methodology for assessing tradeoffs between preferred technology (once through lakewater cooling) and the alternatives. The review team has identified each area of review as adequate, conditionally adequate or not adequate as a way of summarizing the overall assessment. The terms are defined as: Adequate - Meets expectations for an EIS based on PNNL s experience on nuclear projects. Conditionally adequate - Meets basic expectations for an EIS but needs additional information to be judged adequate. Missing information is not of such significance as to seriously impact the results and conclusions of the EIS. Not adequate - Does not meet basic expectations for an EIS. The ratings given are based on the material reviewed and the review team recognizes that material has been provided to the Darlington Joint Review Panel that was not reviewed by the team. 2.1 Adequacy of the Data Supporting the Evaluation of Alternative for Condenser Cooling Technologies Overall, PNNL found the data provided in the OPG EIS and supporting documents are adequate to support an evaluation of tradeoffs between condenser cooling options. The EIS contains a summary of the available information. The Normal Heat Sink Cooling System Comparison for the New Nuclear - Darlington Project (MPR 2009) and technical support documents submitted by OPG provide a sufficient amount of information to support an alternatives analysis with exceptions discussed in Chapter 4. OPG s response to Information Request 11 (IR11) (OPG 2010a) provides a high-level summary of the cooling system comparison document (MPR 2009). Chapter 4 of this report presents more detail on the adequacy of the data supporting OPG s selection of a preferred condenser cooling technology. 2.2 Adequacy of the Data Interpretation Supporting the Evaluation of Alternative Condenser Cooling Technologies Overall PNNL found the techniques OPG used in data interpretation to be sound and adequate. Techniques used are consistent with those found in evaluations of condenser cooling options seen in our experience. However, the lack of calibration of the lake circulation model used to assess the impact 2.1

14 of cooling options as described in Section 4.2, Surface Water Hydrology is a concern 1. Chapter 4 presents more detail on the adequacy of the data interpretation supporting OPG s selection of a preferred condenser cooling technology. 2.3 Adequacy of the Methodology Supporting the Evaluation of Alternative Condenser Cooling Technologies The decision whether to construct and operate a nuclear power plant requires decision makers to balance the need for electrical power with multiple environmental resource objectives. Because the component of a nuclear plant with the greatest interface with the environment is the condenser cooling system, an adequate analysis of cooling system alternatives is required per section 7.3 of the EIS Guidelines. In this review the PNNL team assessed the adequacy of OPG s methodologies and the completeness of the data and data interpretations presented by OPG in the EIS and supporting documents for the New Nuclear Darlington (NND) facility. The PNNL team then examined the adequacy of the basis of an assessment of tradeoffs of cooling alternatives. In some cases, a tradeoff assessment can be balanced against regulations (for example, radiological releases to the environment). Some impact areas (such as visual impact) do not have a clear nexus to environmental regulations. In these cases, the decision making body weighs the importance of the various impact areas as they make a decision. In the EIS and other documentation, OPG did not always make a clear comparison of the effects from once through condenser cooling versus other cooling technologies. This is further described in Section 4.3, Aquatic Ecology Overall Adequacy of the use of the Plant Parameter Envelope OPG s general approach to evaluating alternative condenser cooling technologies was to perform a bounding analysis based on a plant parameter envelope (SENES 2009a). A plant parameter envelope was defined that effectively brackets the range of variables to be assessed. Alternative means of carrying out the project that were considered part of the PPE include alternative reactor designs and numbers of units and alternatives for condenser cooling. OPG stated that The Project Description for EA Purposes incorporated the individual features and characteristics of each alternative means such that the bounding framework being assessed as the NND Project was fully inclusive (i.e., bracketed) all the conditions represented by the alternative means. (SENES 2009a) In PNNL s experience, the PPE is the set of plant design parameter values that would be expected to bound the design characteristics of the reactor designs that might be constructed. The PPE is a bounding surrogate for information for a reactor of a specific design. The PPE reflects the range in values for each parameter that it encompasses rather than the characteristics of any specific reactor design. PNNL s understanding of the purpose of the PPE approach, based on experience with applications in the United States, is to allow an Early Site Permit applicant to defer the selection of a reactor design until the next stage of licensing rather than to use it as a basis for determining the environmental appropriateness of any given design. Further, the use of a PPE does not negate the need to compare alternative technologies such 1 PNNL discussed this with CNSC Staff on Feb and PNNL was informed that Environment Canada has already provided extensive input in this area. We provide the results of our review but recognize that the concern has been addressed. 2.2

15 as alternative cooling systems. In Chapter 4 of this report, PNNL staff describe when and how the PPE approach used by OPG varies from our experience. As discussed in Section , because no reactor design or cooling-tower technology had been selected for the new nuclear power plant at the Darlington site, OPG developed two scenarios documented in the scope of the project TSD (SENES 2009b) and in the surface water assessment TSD (Golder 2009a). One scenario considered a design that was based on a once-through cooling system, with the reactor design that required the largest raw water flow be taken as the upper bounding case for this scenario (SENES 2009b, Golder 2009a). The other scenario combined several cooling tower types using the largest water requirement as the upper bounding case from the reactor design that required the largest raw water flow for this scenario (SENES 2009b). Each scenario was determined by OPG to be bounding for different components (SENES 2009b). One disadvantage of this approach is that the condenser cooling options were not analyzed individually in some areas where one technology is clearly unique. For example, the visual effects of mechanical draft cooling towers with plume abatement were not considered, rather the worst case plume from the mechanical draft cooling towers was considered Overall Adequacy of the OPG Review of Alternative Condenser Cooling Technologies The range of alternative cooling technologies identified in the Normal Heat Sink Cooling System Comparison for the New Nuclear - Darlington Project (MPR 2009) and in the response to IR 11 (OPG 2010a) were appropriate for the site and were comparable to the technologies generally evaluated in applications for new nuclear power plants in the United States. Other observations related to the overall adequacy of the review of alternative condenser cooling technologies include: In PNNL s experience, when an assessment of the impact of the proposed technology (in this case once through lakewater cooling) is judged to be small, alternative technologies are reviewed in less detail than if the proposed technology were determined to have a larger impact. The approach that OPG has taken where cooling towers are analyzed in less detail than once through lake water cooling is acceptable if it is correct that the impact of once through lake water cooling truly is small. A definition of small that we generally apply is that application of the technology would neither destabilize nor noticeably alter any attribute of the environmental resource. All the subsequent discussion in this report presumes this finding is correct. If once through lake water cooling were determined to have a greater impact, then the analysis of alternative cooling systems would be considered too limited. The limited scope of the PNNL review does not allow a detailed review of the impacts of once through lakewater cooling. A comparison of the alternative condenser cooling water systems should still be made even if all technologies have a small impact because it allows comparison of the tradeoffs. The cooling system comparison report (MPR 2009) indicates that The public has raised concerns about impacts on the lake/shore view. Tall structures, such as natural draft cooling towers, have a visual impact and would be expected to provoke negative public reaction. Cooling tower plumes would also be visible and may provoke a similar public reaction. 2.3

16 Because the visual aspects of the plume were identified as useful for differentiating technologies, the reviewers expected to see a more complete assessment of mechanical draft cooling towers with plume abatement. A picture comparing the vapor plume from a cooling tower with plume abatement with a tower without plume abatement can be found at It appears as though mechanical draft cooling towers with plume abatement were not evaluated to the same extent that other cooling tower technologies were. No detail associated with the evaluation of that technology was found in the review of the material submitted by OPG on the atmospheric environment or public acceptance. OPG eliminated cooling ponds and dry cooling from further consideration based on land use and technology suitability, respectively. This decision is not unreasonable. OPG is already planning to fill aquatic habitat, so it appears that land use is indeed a serious limitation. The reviewers agree that without significant consumptive water use or aquatic biota concerns, the disadvantages of dry cooling 2 do not justify its use. Using terms such as preferred, less preferred, and least preferred, as in IR-11 (see Table 2-1 below) are of limited value to a decision maker. They do not provide a sense of the overall importance. It may be more useful to decision makers to identify where a technology would alter noticeably or destabilize a resource rather than identifying preferences. Terms that we have found more useful to describe an impact finding are: SMALL Environmental effects are not detectable or are so minor that they will neither destabilize nor noticeably alter any important attribute of the resource. MODERATE Environmental effects are sufficient to alter noticeably, but not to destabilize, important attributes of the resource. LARGE Environmental effects are clearly noticeable and are sufficient to destabilize important attributes of the resource These terms are still qualitative but reflect the impact on the environment rather than identify preferences. For example,when one assumes a technology is preferred for all attributes except one and the impact of that one attribute is large, in other words will destabilize some aspect of the environment then the technology may be eliminated even though it is preferred relative to most measures. Table 2.1 summarizes OPG s response to the Joint Review Panel s request regarding review of alternative cooling systems (OPG 2010a). (Based on information presented in the response to IR 11 OPG appears to consider hybrid wet dry towers as limited to plume abated wet mechanical draft towers). 2 Cooling tower for the closed-circuit cooling of water with no direct contact between the water to be cooled and the coolant air. The heated water - similarly to a motor radiator - is cooled by air and returned to the condenser. 2.4

17 Table 2.1. Summary of the Review of Alternative Cooling Systems Prepared by OPG in Response to IR 11 (OPG 2010a) Atmospheric Environment Surface Water Environment Aquatic Environment Terrestrial Environment Geological and Hydrogeological Environment Radiation and Radioactivity Once- Through Lakewater Cooling Natural Draft Cooling Towers Mechanical Draft Cooling Tower Fan Assisted Natural Draft Cooling Tower Hybrid Wet Dry Cooling Tower Air Quality P L L L L Noise P L E E E Lake Circulation L P P P P Shoreline Processes L P P P P Lake Water Temperature L P P P P Site Drainage and Water Quality P L L L L Water Consumption P L L L L Aquatic Habitat A L PQ PQ PQ PQ Aquatic Habitat B P L L L L Aquatic Biota P L L L L Vegetation Communities and Species P L E L L Bird Communities and Species P E L L L Mammal Communities and Species P L L L E Insects NA NA NA NA NA Amphibians and Reptiles NA NA NA NA NA Landscape Connectivity NA NA NA NA NA Soil Quality NA NA NA NA NA Groundwater Quality NA NA NA NA NA Groundwater Flow NA NA NA NA NA Radioactivity to Atmospheric NA NA NA NA NA Environment Radioactivity to Surface Water and NA NA NA NA NA Aquatic Environment Radioactivity to Terrestrial NA NA NA NA NA Environment Radioactivity to Geological and NA NA NA NA NA Hydrogeological Environment Radioactivity to Humans NA NA NA NA NA Land Use Land Use P E L L L Landscape and Visual Setting P E L L L Traffic and Transportation Socioeconomic Assets Aboriginal Interests P = Preferred PQ = Preferred with Qualifications L = Less Preferred E = Least Preferred NA = Not Applicable Transportation System Operations P L L L L Transportation System Safety P L L L L Humans Assets NA NA NA NA NA Financial Assets NA NA NA NA NA Physical Assets P E L L L Social Assets P E L L L Traditional Land and Resource Use NA NA NA NA NA Ceremonial Sites and Significant NA NA NA NA NA Features 2.5

18 In our experience it has been important that the impact determinations used in a tradeoff analysis have a clear significance to a decision maker. The number of fish expected to be impinged is of little value to a decision maker, whereas, a statement of the likelihood that commercial and sports fishing will be noticeably degraded is useful to a decision maker albeit less quantitative. Metrics such as lake circulation, shoreline process, and lake water temperature have no clear nexus to impacts. Such metrics need to be translated into resource impacts and in and of themselves provide little insight into the tradeoffs. 2.4 Adequacy of the OPG Review by Environmental Component This section briefly analyzes the adequacy of OPG s review by the environmental components requested in the Statement of Work Atmospheric Environment PNNL finds OPG s assessment of meteorology including fogging, icing, water and salt deposition, visible plume, and shadowing using the SACTI plume model to be conditionally adequate, with the following caveats: Influence from shoreline fumigation on atmospheric dispersion is addressed in LTPS IR#13. However, other characteristics of land/lake breezes, including wind circulation and the associated changes in ambient air temperature and humidity, are not explicitly treated in the SACTI model and may result in plume patterns that are different than those predicted by the model. In general, the EIS does not discuss complications from the land/lake breeze, if any. Additional cooling technologies, including hybrid cooling towers, dry cooling towers, and cooling ponds are not evaluated explicitly in the EIS, but are discussed more generally in a cooling system comparison study (MPR 2009) and response to information request (IR11) (OPG 2010a). These alternative condenser cooling technologies would result in different atmospheric environment impacts than those analyzed in the EIS. For example, a visible plume would not be associated with these cooling technologies. PNNL finds OPG s assessment of air quality impacts including particulates from cooling tower drift using the U.S. Environmental Protection Agency s (EPA s) AP-42 emission factors and AERMOD dispersion model to quantify increased particulates conditionally adequate, with the following caveats: OPG s analysis assumes drift rates for both mechanical and natural draft cooling are to be percent. Higher drift rates may result in greater particulate impacts. Influence from shoreline fumigation on atmospheric dispersion is addressed in LTPS IR#13. However, other characteristics that affect plume transport, including the land/lake breeze wind circulation, are not explicitly treated in AERMOD and may result in dispersion patterns that are different than those predicted by the model. In general, the EIS does not discuss complications from the land/lake breeze, if any. PNNL finds OPG s assessment of noise impacts, including noise from operation of the cooling towers using the Cadna-A model to be adequate. 2.6

19 2.4.2 Surface Water Hydrology Based on PNNL s knowledge and experience, PNNL finds OPG s assessment of surface water impacts using the bounding approach to analyze cooling-tower options not adequate with the following recommendations: Table in the Scope of Project for EA Purposes, Technical Support Document New Nuclear Darlington Environmental Assessment (SOP)(SENES 2009b) does not include all reactor types and all cooling-tower options needed to determine that the range of possible water uses and that bounding values are truly the upper bound. To this end, OPG needs to clarify what is meant by average and maximum blowdown discharge. PNNL finds OPG s assessment of lake circulation assessment not adequate with the following recommendations (PNNL discussed this with CNSC Staff on Feb 11, 2011 and we were informed that Environment Canada has already provided extensive input in this area. In that case these findings may have been addressed): Complete the calibration of diffuser performance. PNNL staff experience suggests that incorporation of outfalls (including diffusers) into numerical model grids is problematic and calibration is essential. Complete the calibration of the 3D hydrodynamic model for the wet and dry years indicated in the surface water assessment TSD (Golder 2009a). Following calibration of diffuser performance and for other periods (wet vs. dry years), reassess the environmental effects. Evaluate the effect of grid size on the current pattern. Because the 90 m grid size is larger than the expected plume size (50 m for once-through cooling and 15 m for the cooling-tower option), the velocity from the ports input to the hydrodynamic model may be underestimated. Provide velocity figures at greater detail than shown in the surface water assessment TSD (Golder 2009a), particularly the spatial interval at which velocities are presented. The currents shown in surface water assessment TSD (Golder 2009a) Figures through are generalized and lack sufficient detail to assess the results. Based on PNNL s knowledge and experience, PNNL finds OPG s shoreline process assessment conditionally adequate but considers that the following information would be needed for the assessment to be considered fully adequate: Providing figures from the 3D hydrodynamic model with velocity near the lake bottom to assist in assessing sediment transport characteristics would allow a clearer assessment of effects on lake bottom sediments. Based on PNNL s knowledge and experience, PNNL finds OPG s lake temperature assessment not adequate with the following recommendations (PNNL discussed this with CNSC Staff on Feb 11, 2011 and we were informed that Environment Canada has already provided extensive input in this area. In that case these findings may have been addressed): Complete the calibration of diffuser performance. PNNL staff experience suggests that incorporation of outfalls (including diffusers) into numerical model grids is problematic and calibration is essential. 2.7

20 Complete the calibration of the 3D hydrodynamic model for the wet and dry years indicated in the surface water assessment TSD (Golder 2009a). Following calibration of diffuser performance and for other periods (wet vs. dry years), reassess the environmental effects. Evaluate the effect of grid size on the temperature distribution. Because the 90 m grid size is larger than the expected plume size (50 m for once-through cooling and 15 m for the cooling-tower option), mixing may be enhanced numerically rather than from natural dispersion processes. Based on PNNL s knowledge and experience PNNL finds OPG s drainage and water quality assessment not adequate with the following recommendations: Provide an analysis using the maximum blowdown discharge for mechanical draft cooling towers, not just the average blowdown discharge. Otherwise provide a justification for not using the maximum blowdown discharge as the bounding case. Provide an analysis with actual concentration of contaminants and assess the impact based on the range of potential changes. Because the hydrodynamic model is not completely calibrated and the diffuser processes included in the hydrodynamic model need further calibration, complete the necessary calibrations and reassess the impacts to water quality using the bounding conditions for flow and contaminant concentrations. Based on the clarification provided of average and maximum blowdown discharge, these bounding conditions would be either for the maximum or average blowdown discharge, whichever produces the largest effect on water quality. OPG does not specifically assess the issue of water consumption in the surface water assessment TSD (Golder 2009a). OPG does discuss the issue of withdrawal versus consumption (MPR 2009) and the scope of the project technical support document (SENES 2009b) provides a table of the raw water needs for two cooling-tower technologies along with the average blowdown water flows. PNNL finds OPG s water consumption assessment conditionally adequate with the following recommendation: Provide an analysis of water consumption and blowdown water flows for all cooling-tower technologies being considered (as described in IR11). Otherwise, provide a justification for the presentation of only two cooling-tower technologies presented in SOP Table Aquatic Ecology PNNL finds OPG s assessment of affects from thermal and chemical discharges from cooling tower alternatives to be adequate. OPG s assessment of impacts from impingement using cooling towers was conditionally adequate for comparison to the impacts assessed for the once-through cooling option as specified in Section 7.3 of the EIS Guidelines (CNS 2009) although they could be considered adequate if the purpose of the assessment was to determine if they could be included in the PPE. The impacts from impingement for the cooling tower alternatives were predicted only for alewife (the predominately impinged fish at DNGS) and were based on impingement at FitzPatrick Plant in New York State. FitzPatrick has a once-through cooling system. No reasons were given for not basing this analysis on a facility on one of the Great Lakes with a closed-cycle cooling system. 2.8

21 OPG s assessment of the level of entrainment anticipated with cooling towers was conditionally adequate for comparison to the impacts assessed for the once-through cooling option as specified in Section 7.3 of the EIS Guidelines (CNS 2009), although they could be considered adequate if the purpose of the assessment was only to determine if they could be included in the PPE. The impacts were not calculated but were considered to be extremely low due to the small rate of intake relative to the DNGS flow. OPG s lack of comparison of the entrainment and impingement rates from various condenser cooling systems does not provide a method to determine if a given cooling system alternative would further exacerbate the reported decline in the forage fish base (specifically alewife, which is characterized as the most significant pelagic forage fish species in Lake Ontario ). In addition, the future importance of this forage fish to the ecosystem and its value to resource agencies is unclear Terrestrial Ecology PNNL finds OPG s assessment to be adequate. Impacts on the terrestrial environment, including terrestrial communities and species, bird communities and species, mammal communities and species, insects, amphibians and reptiles, and landscape connectivity Dose to the Public PNNL finds the review of dose to the public from cooling towers adequately described and justified. Doses arising from the use of cooling towers were not separately evaluated for different cooling tower designs, however, this is not a concern because the doses identified for once through cooling and cooling towers were not significantly different and were well below regulatory limits. The radioactive materials released from the proposed reactors (the source term) are the same regardless of the condenser cooling system used. Differences in dose to the public between the condenser cooling systems analyzed are due to how and where the material is released into the lake Land Use PNNL finds the review of land use, visual resources, and transportation impacts to be adequately described and justified. Although quantitative details are not always provided, sufficient information exists regarding the direction and magnitude of change/impact, such that the tradeoffs between the cooling alternatives could be assessed Cultural Environment PNNL finds OPG s assessment of physical and cultural heritage resources, archaeology, built heritage and cultural landscapes, ceremonial sites and significant features to be adequate. The cultural resource surveys that were conducted were limited to land. Cultural resource surveys along the shoreline as well as underwater areas of potential project disturbance should be conducted. The visual impact to cultural resources should be evaluated. 2.9

22 2.4.8 Socioeconomics PNNL finds OPG s assessment of socioeconomic impacts to be adequate. By the nature of the subject, quantitative assessments are not always possible, and qualitative judgment is used. However, OPG made an exerted effort to use quantitative assessments when possible, and their sources are well documented and referenced Human Health and Well Being PNNL finds OPG s assessment of impacts of cooling tower technologies on human health, including members of the public and workers at the NND site to be adequate Costs PNNL finds OPG s assessment of all relevant costs to be adequate as presented in the Normal Heat Sink Cooling System Comparison for the New Nuclear-Darlington Project (MPR 2009). However, we question the rationale for using some of the underlying assumptions and parameters. At the same time, considering the speculative nature of the costs, nothing presented appeared implausible, and the overall ordinal ranking appears reasonable. A closer look at the rationale behind the performance penalties could be warranted considering its overall impact on net present value and tradeoffs between systems. 2.10

23 3.0 Approach PNNL s approach to this analysis started by reviewing several documents provided by CNSC. They included the Guidelines for the Preparation of the Environmental Impact Statement for Ontario Power Generation s Darlington New Nuclear Power Plant Project (CNSC 2009) and the Canadian Environmental Assessment Agency document Addressing Need for, Purpose of, Alternatives to and Alternative Means under the Canadian Environmental Assessment Act (CEAA) In addition, each technical specialist reviewed relevant portions of the EIS, the Normal Heat Sink Cooling System Comparison for the New Nuclear-Darlington Project (MPR 2009), relevant technical support documents, and relevant OPG Information Request Responses. We reviewed CNSC s Guidelines for preparing an EIS as it provides guidance on the scope of information required to be addressed in the OPG Darlington EIS. Part II of the Guidelines provides specific instruction on the technical content to include in the EIS. Specific to PNNL s overall review of the EIS, Section 7.3 of the Guidelines requires an assessment of alternative means for carrying out the project. As part of this assessment, the EIS must describe the environmental impacts from the alternatives as well as provide a relative assessment and associated criteria used to establish the preferred alternative. As noted in the Guidelines, to the extent that it is practical, the EIS should discuss alternative cooling technologies: condenser cooling water system (cooling towers or intake/discharge of lake water through underwater tunnels, including direct and indirect once-through systems and recirculating systems consisting of wet, dry or hybrid system cooling towers with natural or mechanical air circulation) Section 10 requires the EIS to describe the existing environment, comparing baseline conditions to applicable guidelines and standards. Section 11 requires the EIS to describe changes to the environment as a result of the project, including mitigation measures to reduce or control adverse impacts to the environment. 3.1

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25 4.0 Analysis of Cooling System Assessment This section presents a more-detailed analysis of each environmental component PNNL reviewed. Each section 1) discusses relevant EIS guidelines as they relate to impacts from alternative condenser cooling technologies, 2) summarizes OPG s assessment of baseline conditions and impacts, and 3) analyzes the adequacy of OPG s assessment of baseline conditions and impacts. 4.1 Atmospheric Environment This section summarizes OPG s assessment of baseline conditions and impacts to the atmospheric environment from alternative condenser cooling technologies. It discusses meteorology (fogging, icing, water deposition), air quality, and noise levels Relevant EIS Guidelines for the Atmospheric Environment The CNSC Guidelines (CNSC 2009) provide guidance on the scope of information to be addressed in the OPG EIS). Section 7.3 of the Guidelines requires an assessment of alternative means for carrying out the project. Section 10 requires the EIS to include a description of the existing environment, comparing baseline conditions to applicable guidelines and standards. Section provides specific guidance on information to include in the EIS for the atmospheric environment, including discussion on the regional, local, and site climate and meteorological conditions (e.g., temperature, humidity, precipitation, wind) and various weather phenomena, such as fog. This section also requires a discussion of baseline ambient air quality conditions. Section 11 of the Guidelines requires the EIS to describe changes to the environment as a result of the project. Section provides specific guidance as it relates to the atmospheric environment, including a characterization of project air emissions and associated air quality impacts. Section requires a discussion of project noise and associated impacts Summary of OPG s Assessment of the Atmospheric Environment Baseline Conditions and Condenser Cooling Impacts The OPG EIS (SENES 2009a) evaluated atmospheric impacts for the following condenser cooling technologies: Once-through Lakewater Cooling Natural Draft Cooling Towers Mechanical Draft Cooling Towers Fan-assisted Natural Draft Cooling Towers. 4.1

26 Other condenser cooling technologies, namely cooling ponds, hybrid cooling towers, and dry cooling towers were not evaluated in the EIS for various reasons, including capital costs, land constraints, and perceived performance inefficiencies (SENES 2009a). However, OPG did discuss these technologies more generally in a cooling tower comparison study (MPR 2009) and response to the Joint Review Panel s Information Request (IR#11) (OPG 2010a) Atmospheric Environment Baseline Conditions OPG describes the baseline atmospheric environment in Section 4.2 of their EIS (SENES 2009a); supporting detail is provided in a companion atmospheric environment TSD titled Atmospheric Environment Existing Environmental Conditions Technical Support Document New Nuclear Darlington Environmental Assessment (SENES 2009c). Atmospheric environment baselines conditions discussed in the EIS relevant to the evaluation of impacts from alternative condenser cooling technologies include meteorology, air quality, and noise levels. OPG summarizes baseline meteorological conditions for the regional, local, and site areas in Section of the EIS and Section 3.0 of the atmospheric conditions TSD (SENES 2009c). Meteorological summaries are provided for temperature, precipitation, fog, wind, and mixing height. Baseline meteorological conditions are established through the use of observations from nearby stations (e.g., airports) as well as data from an onsite station. Baseline air quality for the regional, site, local area is presented in Sections and of the EIS. Supporting detail for establishing air-quality baselines is presented in Section 4.0 of the atmospheric conditions TSD (SENES 2009c). Section 3.1 of the atmospheric conditions TSD (SENES 2009c) identifies the criteria for assessing impacts to air quality. Existing air quality is established through monitoring stations operated by the Ministry of Environment (MOE), monitoring data collected on- and off-site by OPG, as well as air modeling of local sources. The latter method uses the U.S. Environmental Protection Agencies (EPA s) AERMOD dispersion model and focuses principally on establishing baseline concentrations at sensitive (risk, socioeconomic, and terrestrial) receptors from existing pollution sources operating at Darlington Nuclear Generating Station (DNGS), the adjacent St. Mary s Cement Bowmanville Plant, and vehicular traffic on local roads. Baseline noise levels for the existing site are presented in Section of the EIS; supporting detail is provided in Section 5.0 of the atmospheric conditions TSD (SENES 2009c). Section of the atmospheric conditions TSD identifies the criteria for assessing impacts from stationary sources, including cooling towers. Existing noise levels were established using both site monitoring (Section 5.2) and modeling (Section 5.3) (SENES 2009c). Modeled values (using the Cadna-A model) were compared to measured values to ensure realistic results for establishing baseline noise levels. Sensitive receptors and sources identified in the air quality modeling were also used in the baseline noise modeling Atmospheric Environment Impacts Impacts to the atmospheric environment baseline are presented in Section 5.2 of the EIS (SENES 2009a); supporting detail is provided in the companion atmospheric assessment TSD entitled Atmospheric Environment Assessment of Environmental Effects Technical Support Document New Nuclear Darlington Environmental Assessment (SENES 2009d). Atmospheric environment impacts discussed in 4.2

27 the EIS relevant to the evaluation of alternative condenser cooling technologies include meteorology (fogging, icing, water and salt deposition, visible plume, and shadowing); air quality (particulates), and noise levels. Regarding meteorology and air quality, OPG notes in Section 3.1 of their atmospheric assessment TSD (SENES 2009d) that there are no Federal or Provincial criteria for assessing effects related to cooling tower operation effects. They go on to cite the U.S. NRC s NUREG 1555, Standard Review Plans for Environmental Reviews for Nuclear Power Plants for limited criteria in evaluating environmental impacts from cooling towers as it relates to salt drift, fogging, and icing (SENES 2009d). To assess these impacts, OPG used the Seasonal Annual Cooling Tower Impacts (SACTI) model. Details of the SACTI model implementation are presented in Section 5.2 and Appendix E of the atmospheric assessment TSD (SENES 2009d). Four SACTI simulations were evaluated two scenarios for mechanical draft towers (circular and linear configuration scenarios) and two scenarios for natural draft towers (two and four tower scenarios). Fan-assisted natural draft cooling towers were not explicitly evaluated; OPG assumed atmospheric impacts are bounded by the mechanical and natural draft cooling tower impacts (SENES 2009a). Using the SACTI model results, assessments on cooling tower impacts to the atmospheric environment are presented in Section of the EIS (SENES 2009a) and Section 6.3 of the atmospheric assessment TSD (SENES 2009d). No icing or fogging impacts occurred with natural draft cooling towers (SENES 2009a). No meaningful change, relative to baseline, was noted for mechanical draft cooling towers (SENES 2009a). Impacts due to water deposition, relative to baseline precipitation for the area, were found to be negligible for all cooling tower scenarios. Visible plumes and salt deposition did occur, and these impacts were evaluated in other affected valued ecosystem components (VECs), including the terrestrial environment, land use, and socioeconomic environments. Air quality impacts from dissolved solids in cooling tower drift are summarized in Section of the EIS and of the atmospheric assessment TSD (SENES 2009d). Particulate emission estimates are made using the U.S. EPA s AP-42 emission factors. The particulate emissions are modeled in the U.S. EPA AERMOD dispersion model; resulting concentrations did not result in additional exceedances to ambient air quality criteria for particulates. Regarding air quality impacts from chemicals, Section of the TSD notes that drift emissions may include water treatment biocides, anticorrosives, and anti-scalants. However, the exact treatment chemicals are not known and OPG assumes no appreciable release to the atmosphere (SENES 2009d). Noise impacts associated with the operation of the cooling towers are summarized in Section of the EIS (SENES 2009a) and Section 6.4 of the atmospheric assessment TSD (SENES 2009d). Of the four noise scenarios modeled in the Cadna-A model, two scenarios included impacts from the operation of cooling towers. However, these scenarios also include cumulative noise impacts from all other sources associated with construction and/or operation of the plant. In either case, OPG found the average daytime and nighttime sound level increases to be less than the applicable standard. 4.3