ANSI/ANS-3.11-2005 American National Standard for Determining Meteorological Information at Nuclear Facilities

1
ANSI/ANS-3.11-2005American National Standard
forDetermining Meteorological Informationat
Nuclear Facilities

• R. Brad Harvey, CCM
• Physical Scientist
• Office of Nuclear Reactor Regulation
• U.S. Nuclear Regulatory Commission

2
Presentation Topics

• History of U.S. NRC Meteorological Monitoring
  Guidance
• ANS/ANSI 3.11-2005
• Potential Updates to U.S. NRC Meteorological
  Monitoring Guidance
• 3rd Proposed Revision 1 to RG 1.23

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Safety Guide 23 (RG 1.23)

• Issued in Feb 1972
• Guidance Topics
• Parameters
• Minimum 2 levels of wind speed, wind direction,
  temp
• Dew point or humidity where there is an potential
  for increased fogging/icing
• Siting
• Tower at same elevation as plant
• Avoid influence of nearby structures
• Measurements at
• 10m
• Vent release height
• Stack height (if applicable)

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Safety Guide 23 (RG 1.23)

• Guidance Topics (contd)
• Data recording
• Dual recorders (2 digital or 1 analog/1 digital)
• Instrument Accuracy
• Wind direction 5 (instantaneous values)
• Wind speed 5mph (time average)
• Temperature 0.5C (time average)
• Delta-temperature 0.1C (time average)
• Dew point 0.5C (time average)

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Safety Guide 23 (RG 1.23)

• Guidance Topics (contd)
• Maintenance and Servicing
• 90 data recovery goal
• Semiannual calibrations
• Data reduction and compilation
• Data averaged over 1560 min
• Compiled into annual Joint Frequency
  Distributions
• Stability based on delta-T or sigma-theta

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Safety Guide 23 (RG 1.23)

• Guidance Topics (contd)
• Special Considerations
• Additional monitoring in complex terrain
• Precipitation and Solar Radiation may be
  desirable
• Documentation
• Describe program in FSAR

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(1st) Proposed Rev. 1 to RG 1.23

• Issued in Sept 1980 (post-TMI)
• Additional Guidance
• Siting
• Avoiding structure influences
• Instrument boom length/orientation
• Aspirated temperature shields
• 10m 60m measurement heights, higher for stacks
• Additional monitoring for coastal valley sites

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(1st) Proposed Rev. 1 to RG 1.23

• Additional Guidance (contd)
• Data Recording
• Sampling rates
• CR/TSC/EOF displays
• System Accuracy
• Data Reduction Compilation
• Hourly averages
• Hourly database submittal
• Quality Assurance
• 10 CFR Part 50 Appendix B

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(1st) Proposed Rev. 1 to RG 1.23

• Additional Guidance (contd)
• Special Considerations for Emergency Preparedness
• Independent 10m backup tower
• Remote interrogation

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ANSI/ANS-2.5-1984

• Approved in September 1984
• Many aspects in common with Proposed Rev. 1 to RG
  1.23
• Did not include Special Considerations for
  Emergency Preparedness
• No references to 10m backup tower or remote
  interrogation
• Reaffirmed in 1990 withdrawn in 2000

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2nd Proposed Rev. 1 to RG 1.23

• Issued in April 1986
• Endorsed ANSI/ANS-2.5-1984
• Took exception to ANSI/ANS-2.5-1984 QA program
  guidance

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ANSI/ANS-3.11-2000

• Approved in February 2000
• Expanded Applicability to Nuclear Facilities in
  Public Sector (e.g. National Labs)
• Cooperative Effort
• NUMUG
• DMCC
• Moved ANS Subcommittees
• From ANS-2 Site Evaluation
• To ANS-3 Reactor Operations

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ANSI/ANS-3.11-2000

• Guidance Topics
• Meteorological Measurements
• Siting of Meteorological Instrumentation
• Data Acquisition
• Data Base Management
• System Performance
• Appendixes (for information only)

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ANSI/ANS-3.11-2005

• Approved by ANS December 2005
• Awaiting approval by ANSI before publishing
• Updates/Enhancements
• System calibration methods
• System accuracy calculations
• Editorial and clarity changes

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ANSI/ANS-3.11-2005

• Meteorological Monitoring System
• Basic Meteorological Measurements
• Wind speed, wind direction, temp, precip
• Supplemental Meteorological Measurements
• Moisture, solar/net radiation, pressure, mixing
  height, etc.
• Remote Sensing Technologies
• Sodar, radar wind profilers, NEXRAD, satellite
  data, etc.
• Sources of Other Surface Observations
• Meteorological Observation Towers
• Stability Class Determination
• Delta-T, sigma theta, sigma phi, Monin-Obukhov
  length, etc.

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ANSI/ANS-3.11-2005

• Instrument Siting
• Topographic Effects
• Flat terrain, mountain, and shoreline sites
• Instrument Orientation
• Aerodynamic effects of obstacles, diabatic
  effects
• Optional Site Selection Techniques
• Remote sensing, tracer studies, numerical
  modeling, physical modeling, etc.

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ANSI/ANS-3.11-2005

• Data Acquisition
• Recording Mechanisms
• Primary system digital
• Optional backup system analog or digital
• Sampling Frequencies
• Averaging At least 30 samples at intervals no
  longer than 60 sec spaced over not less than 10
  min period
• Standard Deviation more frequent sampling
• Data Processing
• 10-15 min averages for display in CR/TSC/EOF
• Hourly averages for climatic and dispersion
  analyses

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ANSI/ANS-3.11-2005

• Data Base Management
• Representative Site Data Bases
• 3-5 yrs of onsite data for dispersion
  calculations
• Data Validation Techniques
• Compare to expected range of values, redundant
  sensors, other tower levels, other data sources,
  etc.
• Data Substitution
• From redundant sensors, other tower levels
  (adjusted for change in height), linear
  interpolation for short periods of missing data,
  etc.

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ANSI/ANS-3.11-2005

• Data Base Management (contd)
• Data Recovery Rates
• 90 annually, individual channels and composite
  WS/WD/DT joint frequency distributions
• Data Archiving
• Retain raw data for 5 years, valid hourly data
  for life of facility
• Data Reporting
• Annual joint frequency distributions

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ANSI/ANS-3.11-2005

• System Performance
• System Accuracy
• Wind Speed 0.2 m/s or 5 of observed
• Wind Direction 5
• Temperature 0.5C
• Delta-T 0.1C
• Dew Point 1.5C
• Time 5 min
• Etc.

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ANSI/ANS-3.11-2005

• System Performance (contd)
• System Calibrations
• Encompass entire channel (from sensor to
  display/recorder)
• Preoperational and 6-month intervals thereafter
• Document as-found and as-left results
• Field versus laboratory calibrations
• System Protection, Maintenance Service
• Protect against electrical faults, severe
  environmental conditions, etc.
• Quality Assurance and Documentation

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ANSI/ANS-3.11-2005

• Appendixes (for information only)
• Supplemental Measurements
• Tower Siting in Complex Terrain
• Stability Class Determination
• Optional Site Selection Techniques
• Wind Computations
• Calibration Practices

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3rd Proposed Rev. 1 to RG 1.23

• Part of ongoing overall effort to update
  regulatory guidance to support expected new
  reactor applications
• May include consideration of guidance provided in
  ANSI/ANS-3.11-2005
• Tower and instrument siting criteria
• System accuracy
• Data processing, recording, and displays