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

	Joint frequency wind and rainfall distributions
	Concentration X/Qs
	Finite-cloud gamma X/Qs
	D/Qs
	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.

	Implementation of the following models: Long-term dispersion and deposition models in Regulatory Guide 1.111 for routine releases The models in Regulatory Guide 1.145 for short-term, accidental releases A model similar to that in the XOQDOQ code for intermittent releases Adaptation of the Murphy/Campe dispersion equation for close-in receptors, based on 95% meteorology and user-specified wind-direction sectors affecting the receptors
	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: Use of multi-year hourly meteorological data (wind direction, wind speed, vertical temperature difference, and, optionally, rainfall and solar radiation) Straight-line trajectory models with Gaussian diffusion (inclusive of plumes which follow the valley in the deep-river-valley option) Concentration and gamma (X/Q) models (see Footnote 1) (plume centerline and sector- average) Depletion and deposition models [two options: (a) the models in Regulatory Guide 1.111, and (b) models making use of the deposition-velocity concept] Extrapolation of wind speed with height Partial plume entrainment at the release point (split-H model, with part-time elevated and part-time ground-level releases) Building wake effects The Murphy and Campe building-wake methodology for close-in receptors Plume meander effects Plume rise effects (buoyant or momentum) User-specified terrain features Vertical reflection correction in all cases, and horizontal reflection correction in valley flows Recirculation correction factors (built-in values for open terrains, or user-specified values) In-transit decay correction (two user-specified decay constants, one for noble gases and one for halogens) User-specified halogen and noble-gas relative isotopic concentrations, or gamma spectra, for the finite-cloud gamma (X/Q)s Preparation of joint-frequency distributions (atmospheric stability, wind direction and wind speed; rainfall; sea breezes; up-valley and down-valley flows and associated rainfall)
	Outputs which include the following dispersion and deposition parameters: For routine, continuous releases: The plume centerline concentration (X/Q) The sector-average concentration (X/Q) The plume centerline finite-cloud gamma (X/Q) The sector-average finite-cloud gamma (X/Q) The plume centerline decayed (D/Q) The sector-average decayed (D/Q) For intermittent and accidental releases: The hybrid concentration (X/Q) The hybrid finite-cloud gamma (X/Q) The hybrid (D/Q) where: (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 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 The results for accidental releases include tables for each sector independently, and for all sectors combined (overall-site model)
	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.
	FORTRAN 77; 7900 coded lines; DOS and UNIX applications; ASCII file input; 132-column output

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"

	P100-R19-A - Technical description
	P100-R19-B - Program Listing
	P100-R19-C - Implementation Test Runs
	P100-R19-D - Code Verification Test Report
	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).