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Meteorological Considerations in Preparing a COLA for a Nuclear Power Plant Located at a Greenfield Site

Ping Wan Bechtel Power Corporation The 12 th Nuclear Utility Meteorological Data Users Group Meeting June 2008. Meteorological Considerations in Preparing a COLA for a Nuclear Power Plant Located at a Greenfield Site. Preparing A Combined License Application. Offsite Data Requirements

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Meteorological Considerations in Preparing a COLA for a Nuclear Power Plant Located at a Greenfield Site

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  1. Ping Wan Bechtel Power Corporation The 12th Nuclear Utility Meteorological Data Users Group Meeting June 2008 Meteorological Considerations in Preparing a COLA for a Nuclear Power Plant Located at a Greenfield Site

  2. Preparing A Combined License Application Offsite Data Requirements • Representativeness of the offsite data source • Suitable for use to establish Meteorological Design Criteria for plant components

  3. Preparing A Combined License Application Onsite Data Requirements • Representative of overall site meteorology • Adequate data length and recentness of the meteorological records • Valid, accurate and defendable • Representative of long-term conditions • Suitable for making dispersion estimates

  4. Regulatory Requirements and Guidance Partial List • R.G. 1.23, Rev. 1, 1.97 Rev. 4 • R.G. 1.111, 1.145, 1.194, 1.78 • NUREG 0800, Rev. 3 • NUREG 1555 • NUREG 1.206 • NUREG 0654, 0696, 0737, 0523 • ANS / ANSI 3.11

  5. Representative of an Offsite Data Source Depending on: • Proximity to the site • Differences in topography • Terrain elevation • Land use • Closeness to large bodies of water • Methods of data collection • Techniques of data recording

  6. Design and Operating Meteorological Basis • Snow Load on Roofs of Safety-Related Structures • Weight of 100-year return period snowpack, and • 48-hour PMWP • Wind Loading on Plant Structures • 100-year return period (straight-line) 3-second gust wind speed • UHS Meteorological Conditions • Maximum evaporation and drift loss of water, and • Minimum water cooling, and water freezing in the storage facility

  7. Design and Operating Meteorological Basis • Tornado Parameters for Pressure and Tornado Missile Loadings on SSC Important to Safety • Maximum translational and rotational speed, and • Maximum pressure differential with the associated time interval • Ambient Temperature and Humidity Statistics for Design Heat Loads • 2% and 1% annual exceedance and 100-year Max. DB and Coincident WB, • 2% and 1% annual exceedance and 100-year Max. WB (non-coincident), and • 98% and 99% annual exceedance and 100-year minimum DB

  8. Length & Recentness of Records For a COL Application • A two consecutive annual cycles (preferably 3 or more whole years), including the most recent 1-year period • Meteorological data in the form of joint frequency distribution of wind speed, wind direction by atmospheric stability class as described in R.G. 1.23 • An electronic listing of all hourly averaged data • At least one annual cycle of onsite meteorological data at the time of docketing

  9. Onsite Meteorological Monitoring Program • Pre-application Monitoring • Data collection is used to prepare the COLA. • Establish a baseline for impact assessing impacts. • Site Preparation and Construction Monitoring • Control anticipated impacts • Detect any unexpected impacts • Pre-operational Monitoring • Establish a baseline to reflect the as-built environment for identifying and assessing impacts. • Operational Monitoring • Establish a baseline for evaluation of impacts and support emergency preparedness planning.

  10. Meteorological Data Collection System • Meteorological tower and instrument siting • Meteorological parameters measured • Data acquisition and reduction • System accuracy • Instrument surveillance • Quality assurance and documentation

  11. Meteorological Tower and Instrument Siting • Base of the tower at approximately the same elevation as the finished plant grade of the new units • Location of tower upwind of the existing and new plant cooling system • Upper measurement level of the tower within the TIBL for coastal or lakeshore sites • Sensor location at least 10 obstruction heights away from such obstructions • Wind sensors located on mast away from tower structure influence • Ambient temperature and humidity sensors located away from existing and proposed moisture sources

  12. Typical TIBL Event Internal Boundary Layer H Warm Wind Flow Land H Cool Water Cool

  13. Meteorological Parameters Measured • Wind speed and wind direction at 2 levels (at 10- and 60- meter, which generally coincides with the routine release level for LWRs), and at the stack release height (if applicable) • Delta-T between 10- and 60-meter, and 10- and the stack release height • Ambient temperature at 10 meters • Atmospheric moisture at 10 meters, and at the top of the cooling tower (if applicable) • Precipitation on the ground at or near the tower

  14. Adequate, Valid and Defendable Data Depending on: • Redundant Data Collection system • Data Acquisition and Reduction • System Accuracy • Instrument Surveillance, and • Quality Assurance and Documentation

  15. Climatic Representative • Evidence should be provided to show how well the onsite met data represent long-term conditions at the proposed site. • The climatic representativeness of the onsite meteorological data can be checked by comparison with nearby stations with similar geographical locations and topographical settings that have reliable long-term meteorological data.

  16. Use of Meteorological Data

  17. Control Room Habitability Assessment Meteorological considerations used to evaluate the personnel exposures inside the control room due to accidental release of: • Hazardous Chemicals • store onsite and at nearby offsite facilities • transport on nearby highway, rail and/or waterway • Radiological Material • During design-basis radiological accidents ( e.g., LOCA, Steam Line Break, Fuel Handling

  18. Site Acceptability and Safety Analysis Due to a Design-basis Accident • Radiological dose consequences of postulated accidents meet prescribed dose limits at : • Exclusion Area Boundary • Low Population Zone • X/Q estimates at: • EAB: 0-2 hours • LPZ: 2-8 hours, 8-24 hours, 1-4 days and up to 30-day averaging periods

  19. Individual and Population Dose Projection During Normal Operation • Radiological effluent release limits can be met for any individual located offsite. • X/Q estimates at: • the site boundary, • nearby resident, cow/goat and vegetable garden • population out to 50-mile radius of the plant

  20. Environmental Risk Evaluation • The potential dispersion of radioactive material from a spectrum of severe accidents • The radiological consequences of a spectrum of severe accidents • MELCOR Accident Consequence Code System, Version 2 (MACCS2) • a statistical stochastic diffusion model • including removal of particulate radio-nuclides from the plume by wet deposition

  21. Non-Radiological Environmental Impacts • Heat Dissipation System • Cooling tower, Cooling reservoir, cooling canal • Visible plume, Fogging, Icing, Salt Deposition • Auxiliary Boiler, Standby Diesel Generator, Concrete-batch Plant, and Diesel-Driven Construction Equipment • Air emissions – SO2, NO2, PM10, PM2.5, CO • Degradation of ambient air quality • Visibility impacts on Class I Area

  22. Emergency Preparedness and Response • Real-time display of 15-minute averages of wind speed (WS), wind direction (WD) and atmospheric stability class (Delta-T) • Submitted WS/WD/Delta-T as input to the NRC’s ERDS • Making near-real-time atmospheric transport and diffusion estimates within the EPZ • Provision of alternative sources of meteorological data • The tower and its instrumentation capable of surviving monitoring, and displaying the meteorological conditions for execution of emergency action levels

  23. Conceptual View of Atmospheric Processes

  24. Atmospheric Dispersion • Where does the material released to the atmosphere go? • How rapidly does it dilute in getting there? • How rapidly and by what mechanisms is it removed from the atmosphere? = Transport + Diffusion + Deposition

  25. What Models and Assumptions To Be Used? Depending on: • Release characteristics and amount • Distance from the release location to the receptor of interest • Nature of terrain within the modeling domain • Length of time needed to be modeled • Amount of available meteorological data

  26. Dispersion Modeling Guidance & Tools Sample List

  27. Summary Criteria for a successful COL Application • A valid, accurate, representative and complete meteorological data base • Use most recent and readily available offsite meteorological and climatological data • Use up-to-date meteorological information and references • Close coordination and cooperation between the regulatory agency, other COLA preparers, and permit applicants

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