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Atmospheric Radionuclide Transport Model (ARTM) and Dose Model (DARTM)

  • The dispersion model ARTM combined with the radioecological model DARTM is used for the calculation of the additional exposure of members of the public in the surrounding of nuclear facilities.
  • For the atmospheric dispersion simulations of radionuclides time series of meteorological measurements, environmental data as well as the emission data of radioactive substances from the exhaust stack are used.

The picture shows the annual air activity caesium-137 ARTM-Model: Average ground-level yearly air activity of caesium-137ARTM-calculated average ground-level air activity from constant yearly caesium-137 discharge of one Becquerel per second at 160 m emission height

The Atmospheric Radionuclide Transport Model (ARTM) was developed on behalf of the German Federal Environment Ministry (BMUV) and the German Federal Office for Radiation Protection (BfS). It is used together with the radioecological model DARTM for the calculation of the exposure of members of the public in the vicinity of nuclear facilities during normal operations. This simulation tool is continuously adapted to latest state-of-the-art of science and technology. DARTM was recently revised and adapted to the German general administrative regulation ("AVV Tätigkeiten").

As necessary input parameters, ARTM requires

  • time series of meteorological measurements at the site of the nuclear facility regarded,
  • emission data of radioactive substances from the exhaust stack and
  • environmental data.

DARTM uses the following input parameters:

  • results of ARTM simulations
  • information on landuse and possible time spent in work, outside and sheltering.

The additional exposure of members of the public caused by artificial radioactive substances must be reported annually to the German Parliament since 1974.

The Atmospheric Radionuclide Transport Model (ARTM)

The current Radiation Protection Ordinance, stipulates the use of a Lagrangian Particle Dispersion Model for calculating the exposure of members of the public in the vicinity of nuclear installations. Therewith, the Lagrangrian Particle Dispersion Model replaces the previously applied Gaussian Plume Model, which was allowed to use until the end of 2020.

For this purpose, the AUSTAL2000 code package designed for modelling the dispersion of conventional air pollutants was adapted and improved to consider the dispersion of airborne radioactive substances resulted in the Atmospheric Radionuclide Transport Model (ARTM).

ARTM SpecificationShow / Hide

Based on the "TA Luft" and the code package AUSTAL2000, the program system ARTM for calculating the dispersion and deposition of discharged airborne radioactive substances represents the latest state-of-the-art in science and technology (VDI-GL 3945, Sheet 3).

A standardised procedure for conventional (AUSTAL2000) and radio-ecological (ARTM-DARTM) applications provides a high level of legal certainty to the user.

Compared to the classic Gaussian Plume Model, the simulation of atmospheric dispersion and deposition using an advanced Lagrangian Particle Dispersion Model in combination with a flow model and a state-of-the-art turbulence parametrization provides more flexible and realistic modelling for licensing-related and retrospective applications.

ARTM FunctionalityShow / Hide

  • Simulating atmospheric dispersion of discharged radioactive substances
  • Meteorological conditions as time-series for mean hourly values (time-dependent) or four-dimensional dispersion statistics (wind direction, wind speed, dispersion class, precipitation rate)
  • Time dependent fluid flow (wind) model regarding orography and buildings
  • Non-uniform emissions on an hourly basis
  • Several sources, ground-level sources, point sources, line sources, area sources
  • Variable computational grid, nested grids
  • Dry and wet deposition
  • Weather dependent plume rise
  • Graphical display of concentration and deposition
  • Editing of model parameters

Additional functions compared to AUSTAL2000Show / Hide

  • Gamma submersion (radiation from the cloud)
  • Wet deposition
  • Variable turbulence parametrisation (boundary layer model)
  • Radioactive decay during dispersion
  • Formation of daughter nuclides in the case of radon-222 (post-processor)
  • Usage of approximately 800 radionuclides
  • Consideration of special properties of some "special" radionuclides
  • Export of the results for geo-browsers (kml-export)
  • Additional programs for post-processing of the output data (e.g. predefinition of excluded areas)
  • Graphical user interface for parameter setting and graphical outputs.

  • In addition, interfaces with the existing calculation guides

    have been implemented, therefore dose calculations are not included; the dispersion calculation rather ends at the interface with the dose section of the calculation guide. This permits dose calculations using alternative dose models beyond the calculation guides provided by AVV and SBG.

  • ARTM, including verification and validation, has been developed within the scope of research projects. Upon conclusion of the first project an extensive test phase was implemented involving users from different institutions the results of which were entered into subsequent projects. Furthermore, ARTM successfully took part on numerous international validation experiments.

Further DevelopmentShow / Hide

ARTM development is an ongoing process, especially in regard to the following main emphases:

  • Checking of input-data to avoid abnormal terminations, e.g. errors in time series, problems with divergence due to orography.
  • Possibility to the manual set of mixing layer parameters.
  • Multiple technical improvements and optimisation in regards to duration of runs, operation mode, parallelization, program stability and user interface.
  • Extensive documentation of the simulation tool.
  • Improvement of the outputs of the radon-post-processor.

Radioecological model for exposure calculations DARTM

The radioecological model DARTM developed by BfS calculates the exposure of members of the public arising from airborne radioactive substances. DARTM can only be used in combination with the atmospheric dispersion model ARTM, since DARTM uses input files and output files from ARTM-calculations.

DARTM has been revised. The previous DARTM version (5.2) was developed for reference persons according to the AVV on § 47 Radiation Protection Ordinance of 2011, which expired on 31 December 2018. With DARTM the annual amounts of the individual organ dose and effective dose of a reference person can be assessed.

Within the framework of a research project, DARTM 5.2 has been verified by independent consultants. This project was concluded in 2016, the resulting findings have been addressed and included into the recent version (5.2). This verification allows the application of DARTM for regulatory purposes. The DARTM version 5.2 is freely available, however it does not fulfil the requirements of the representative person.

New: DARTM 6.1

In the course of the revision of the Radiation Protection Ordinance on 31 December 2018, a general administrative regulation for calculating the exposure of members of the public ("AVV Tätigkeiten") was implemented. The most important modifications were:

  • Determining the dose of a representative person instead of a reference person.
  • The various conservative assumptions on living habits are replaced with more realistic ones.

Therefore a new software for dose computation according to the AVV had to be developed. This new DARTM version 6.1 fulfils the current administrative regulations and was verified by independent consultants. The resulting findings have been addressed and included into the recent version (6.1). This verification allows the application of DARTM for regulatory purposes. At the moment, DARTM 6.1 is licenced only for German authorities.

Using DARTM

If you are interested in the DARTM 6.1 program or the DARTM 5.2 program, please send an e-mail to artm@bfs.de and indicate which of the programs you would like to use.

Legal notices regarding the provided software

  • DARTM and the software LBM-Ing and ARTM-OSM can be used only by German authorities.
  • As far as legally applicable the BfS takes no liability for potential damages that could occur either while calling up or downloading data caused by viruses, or during installation or usage of the software (see also the legal notice).
  • The BfS does not provide any warranty for the correctness of the values calculated with DARTM.
  • The verification of DARTM 6.1 ended in 2023.

Scientific Background

Determination of the Exposure of members of the public (dose)

Radioactive substances discharged from nuclear facilities via exhaust air and waste-water contribute to the members of the public. Therefore, operators are obliged to provide assessments of the discharged radioactive substances by type and activity. Based on these data the exposure of members of the public in the vicinity of a nuclear facility can be calculated for the so-called "representative person" defined in the Radiation Protection Ordinance. The dose assessments on public exposures uses the concept of representative person instead of a reference person since 2021.

This fictitious person is assumed to exhibit a likely "conservative" behaviour as to his whereabouts and food patterns, i.e. all assumptions are selected so as to result in maximum possible exposure. However, contrary to the previous concept of "reference person", here extreme or impossible living habits are not considered. The exposure of this representative person is calculated using

  • a Lagrangian Particle Model (such as ARTM for atmospheric dispersion) and
  • a radioecological model.

The former of both models simulates the transport processes of radionuclides e.g. from the stack of a nuclear facility to the air. The separate radioecological model, e.g. DARTM, calculates the exposure of members of the public from the activity concentration and depositions of the regarded radioactive substances received by the dispersion model.

This modular structure of both the dispersion and the dose software yields several advantages. For example, in the course of an amendment of calculation guides, it is easy to make a separate revision of the respective software packages or to apply alternative radioecological or dispersion models.

Lagrangian Transport Model

Calculating the Atmospheric Dispersion: A Lagrangian Transport Model

ARTM is a so-called Lagrangian Transport Model. In contrast to the prior used Gauss Plume Model ARTM is able to take the non-stationary weather into account.

Therefore the 3D wind flow fields are computed according to the time-series of weather parameters. Additionally, the effects of orography as well as of building structures can be simulated if necessary.

As the next step millions of tracers – representing the emission – are numerically advected and dispersed on these 3D flow fields. The evaluation of the distribution of these tracers results in 3D activity concentrations, dry and wet depositions as well as their uncertainty.

Lagrangian Transport Models provide a more realistic description of the spatial distribution of concentrations than Gauss Plume Models:

  • Orography and buildings can be considered.
  • Time-dependent advection-dispersion: “curly” trajectories as effect of the change in the wind direction are captured.
  • More complex spatial distribution of concentration can be detected.
  • Dry and wet deposition are simulated and not assumed.
  • Gamma submersion is calculated for each time step using the form and location of the cloud.

Emissions monitoring of nuclear facilities

State of 2024.10.30

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