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AEOLUS-3
A software package for the determination
of atmospheric dispersion and deposition of nuclear power plant
effluents during continuous, intermittent and accident conditions,
in open-terrain sites, coastal sites and deep-river valleys.
Key Features
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Joint frequency wind and rainfall
distributions |
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Concentration X/Qs |
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Finite-cloud gamma X/Qs |
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D/Qs |
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Distant and close-in receptors
(adaptation of the Murphy/Campe model) |
Basic Features at a Glance
Appendix I to 10CFR50 provides numerical guidance for design
objectives and limiting conditions for operation of light-water-cooled
reactors to ensure that radioactivity releases to the environment
are "as low as reasonably achievable." To implement
this appendix, the Nuclear Regulatory Commission has developed
a series of guides providing acceptable methods for the calculation
of effluent releases, dispersion of the effluents, and the resulting
radiation doses to man. One of the guides, Regulatory Guide 1.111,
describes models and assumptions for estimating long-term concentrations
of radioactive material in the vicinity of nuclear power plants
which would result from routine airborne releases. Another guide,
Regulatory Guide 1.109, describes models and assumptions for calculation
of annual doses to man which would result from such releases.
In addition to the above, and for compliance with the requirements
of 10 CFR Part 100 and 10 CFR Part 50, the Commission has also
issued Regulatory Guide 1.145 which provides guidance on short-term
atmospheric dispersion models for the assessment of consequences
of potential accidents at nuclear power stations.
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Implementation of the following
models:
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Long-term dispersion and
deposition models in Regulatory Guide 1.111 for routine
releases |
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The models in Regulatory
Guide 1.145 for short-term, accidental releases |
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A model similar to that
in the XOQDOQ code for intermittent releases |
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Adaptation of the Murphy/Campe
dispersion equation for close-in receptors, based on
95% meteorology and user-specified wind-direction sectors
affecting the receptors
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Open terrains, coastal sites,
and deep river valleys, with continuous, intermittent and
accidental- release options, the models/features in each case
(or as applicable) including the following:
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Use of multi-year hourly
meteorological data (wind direction, wind speed, vertical
temperature difference, and, optionally, rainfall and
solar radiation) |
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Straight-line trajectory
models with Gaussian diffusion (inclusive of plumes
which follow the valley in the deep-river-valley option) |
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Concentration and gamma
(X/Q) models (see Footnote
1) (plume centerline and sector- average) |
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Depletion and deposition
models [two options: (a) the models in Regulatory Guide
1.111, and (b) models making use of the deposition-velocity
concept] |
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Extrapolation of wind speed
with height |
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Partial plume entrainment
at the release point (split-H model, with part-time
elevated and part-time ground-level releases) |
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Building wake effects |
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The Murphy and Campe building-wake
methodology for close-in receptors |
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Plume meander effects |
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Plume rise effects (buoyant
or momentum) |
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User-specified terrain features |
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Vertical reflection correction
in all cases, and horizontal reflection correction in
valley flows |
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Recirculation correction
factors (built-in values for open terrains, or user-specified
values) |
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In-transit decay correction
(two user-specified decay constants, one for noble gases
and one for halogens) |
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User-specified halogen and
noble-gas relative isotopic concentrations, or gamma
spectra, for the finite-cloud gamma (X/Q)s |
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Preparation of joint-frequency
distributions (atmospheric stability, wind direction
and wind speed; rainfall; sea breezes; up-valley and
down-valley flows and associated rainfall)
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Outputs which include the following
dispersion and deposition parameters:
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For routine, continuous
releases:
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The plume centerline
concentration (X/Q) |
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The sector-average
concentration (X/Q) |
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The plume centerline
finite-cloud gamma (X/Q) |
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The sector-average
finite-cloud gamma (X/Q) |
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The plume centerline
decayed (D/Q) |
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The sector-average
decayed (D/Q)
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For intermittent and accidental
releases:
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The hybrid concentration
(X/Q) |
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The hybrid finite-cloud
gamma (X/Q) |
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The hybrid (D/Q) |
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where:
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(X/Q)s for all
types of releases are calculated for (i)
undecayed, undepleted conditions, (ii) decayed
conditions for noble-gas-release applications,
and (iii) decayed and depleted conditions
for halogen-release applications
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The hybrid model
for intermittent and accidental releases
makes use of log-log plots of the 1-hour
plume centerline values (for the concentration
X/Q, the gamma X/Q and the D/Q) and their
corresponding sector-average values averaged
over the joint-frequency distribution, to
compute 'hybrid' values at intermediate
time intervals of interest
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The results
for accidental releases include tables for
each sector independently, and for all sectors
combined (overall-site model)
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Detailed intermediate-result printout
for any receptor of interest, such as decay correction factors,
wet and dry depletion and deposition factors, horizontal reflection
correction in valleys, dispersion zones and virtual source
distances in sea breeze analyses, ordered arrays of values
in intermittent and accidental releases, etc.
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FORTRAN 77; 7900 coded lines;
DOS and UNIX applications; ASCII file input; 132-column output
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Documentation Package
P100-R19, "AEOLUS-3 - A Computer Code for the Determination
of Atmospheric Dispersion and Deposition of Nuclear Power Plant
Effluents During Continuous, Intermittent and Accident Conditions
in Open-Terrain Sites, Coastal Sites and Deep-River Valleys"
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P100-R19-A - Technical description
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P100-R19-B - Program Listing |
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P100-R19-C - Implementation
Test Runs |
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P100-R19-D - Code Verification
Test Report |
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P100-R19-E - Addendum |
Footnote 1
Physically speaking, the gamma X/Q for a given finite plume defines the equivalent
concentration in a semi-infinite cloud at ground level which will
yield the same gamma radiation exposure as the finite plume itself.
In short, the standard gamma dose rate equation for a semi-infinite
cloud is converted to the dose rate equation for a finite cloud
by simply replacing the concentration (X/Q) in the former with
the gamma (X/Q).
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