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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.

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Presentation on theme: "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."— Presentation transcript:

1 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

2 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 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 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 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 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 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 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 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 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 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 12 Typical TIBL Event

13 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 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 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 16 Use of Meteorological Data Data ApplicationOnsite Data Offsite Data Meteorological Design Criteria of the Plant (e.g., structures, heat dissipation system, UHS, HVAC) V Comparison of onsite and offsite sources to determine the appropriateness of climatological data use for design considerations VV Atmospheric dispersion estimates (X/Q) of design-basis accidents for evaluation of site acceptability and the adequacy of engineered safety features of the plant V Atmospheric dispersion estimates (X/Q) of postulated accidental radiological and toxic airborne releases of effluents for control room habitability assessment V Atmospheric dispersion estimates (X/Q) of routine airborne releases of effluents for individual and population dose projections VV Evaluation of environmental risks from radiological consequences of a spectrum of accidents V Evaluation of non-radiological environmental impacts (e.g., visible plume, fogging, salt deposition) VV Emergency Preparedness and Response Plans including making near-real time X/Q predictions V

17 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 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 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 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 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 – SO 2, NO 2, PM 10, PM 2.5, CO Degradation of ambient air quality Visibility impacts on Class I Area

22 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 NRCs 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 23 Conceptual View of Atmospheric Processes

24 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 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 26 Dispersion Modeling Guidance & Tools Sample List Types of X/Q EstimatesNRC GuidanceTools Routine & Accidental Radiological Releases R.G. 1.111 R.G. 1.145 XOQDOQ PAVAN Control Room Habitability Evaluation (for both chemical and radiological releases) R.G. 1.194 NUREG/CR-6210 R.G. 1.78 NUREG-0570 NUREG/CR-1152 ARCON96 HABIT Emergency Planning and Response (Near Real-time Predictions) (* Modifications required – adding plume tracking capability) R.G. 1.23 NUREG-0654 NUREG-0696, 0737 MACCS2 RASCAL, V2.2 NARAC MESODIF-II* CALPUFF* Environmental Impacts of Cooling Tower Plume No specific guidance EPRI Model - SACTI

27 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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