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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 12th Nuclear Utility Meteorological Data Users Group MeetingJune 2008
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
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 DataData Application Onsite
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
V V
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
V V
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)
V V
Emergency Preparedness and Response Plans including making near-real time X/Q predictions
V
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 & ToolsSample List
Types of X/Q Estimates NRC Guidance Tools
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
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