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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Atmospheric Radionuclid Transport Model (ARTM) and its Dose Module (DARTM)

  • The dispersion model ARTM combined with dose module DARTM is used for the calculation of the radiation exposure on the population in the surrounding of nuclear facilities.
  • As necessary input parameters, ARTM requires time series of meteorological measurements as well as the emission data of radioactive substances from the exhaust stack.
  • The additional radiation exposure on the population caused by the artificial emission must be reported annually to the German parliament since 1974.

The picture shows the annual air activity cesium-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 Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the German Federal Office for Radiation Protection (BfS). It is used together with dose module DARTM for the calculation of the radiation exposure of the population 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.

As necessary input parameters, ARTM requires

  • time series of meteorological measurements as well as
  • the emission data of radioactive substances from the exhaust stack.

The additional radiation dose on the population caused by the artificial emission must be reported annually to the German parliament since 1974.

The Atmospheric Radionuclide Transport Model (ARTM)

In the course of an expert revision of the currently valid calculation basis towards a newly designed calculation guideline, it is planned to replace the presently applied Gaussian Plume model with the more advanced Lagrangian Particle Dispersion Model due to the Technical Guidelines on Air Quality Control (TA Luft) of 24th July 2002.

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 released airborne radioactive materials represents the latest state-of-the-art in science and technology (VDI-GL 3945, Sheet 3 and VDI-GL 3783, Sheet 8)

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 Lagrange Particle Dispersion Model (combined with a flow model and state-of-the-art turbulence parametrization) provides more flexible and realistic modelling for licensing-related and retrospective applications.

ARTM Functionalityshow / hide

  • 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, deposition and time-series for any chosen locations
  • 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" nuclides
  • 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.

Further Developmentshow / hide

ARTM development is ongoing. The main aspects are:

  • Checking of input-data (errors in time series, problems with divergence due to orography) to avoid abnormal terminations.
  • Possibility to the manual set 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.
  • Practical testing, workshops, support and internet presence.

Dose Module for ARTM (DARTM)

The dose program DARTM developed by BfS is freely available. However, DARTM can only be used in combination with the atmospheric dispersion model ARTM, since DARTM uses input files and output files from ARTM-calculations in order to determine radiation exposure from radioactive discharges via air for reference persons according to the AVV on § 47 Radiation Protection Ordinance. The annual amounts of the individual organ dose and effective dose of a reference person are determined.

Within the framework of a research project, DARTM has been verified by independent consultants. This project was concluded in mid 2016, the resulting findings have been addressed and included into the recent version. This verification allows the application of DARTM for regulatory purposes.

Legal notices regarding the provided software

  • The BfS provides the recent version of ARTM including GO-ARTM and DARTM for download.
  • 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. For the rest we refer to the imprint.
  • The BfS does not provide any warranty for the correctness of the values calculated with DARTM.
  • The verification of DARTM has been concluded since mid 2016. Please consider using only the recent version.

Scientific Background

Determination of the Public Radiation Exposure (dose)

Radioactive substances discharged from nuclear facilities via exhaust and waste-water contribute to the radiation exposure of the general public. Operators therefore are obliged to provide assessments of the emitted radioactive substances by type and activity. Based on these data radiation exposure in the vicinity of a nuclear facility can be calculated for the so-called "reference person" defined in the Radiation Protection Ordinance.

This fictitious person is assumed to exhibit a very "conservative" behaviour as to his whereabouts and food patterns, i.e. all assumptions are selected so as to result in maximum possible radiation exposure. Radiation exposure of this reference person is calculated by

  • a dispersion model (such as ARTM for atmospheric dispersion) and
  • a radioecological model using the assembled emission data of the nuclear facility.

The former models are used to simulate the transport processes of radionuclides e.g. from the stack of a nuclear facility to the air.

This calculation of the concentrations of radioactive substances in various environmental media is followed by use of a separate radioecological (dose) module (e.g. DARTM) appropriate to assess the radiation exposure of the public. In the case of atmospheric dispersion DARTM uses the resulted concentration, gamma submersion and deposition rate fields calculated by ARTM. This modular structure of both the dispersion and the dose module 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 dose modules.

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 models 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.

Download software (in German only)

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State of 2018.07.19

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