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Ionising radiation

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

Ionisierende Strahlung

Atmospheric Radionuclid Transport Model (ARTM)

  • The dispersion model ARTM 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 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 employed for the calculation of the radiation exposure of the population in the vicinity of nuclear facilities during normal operations and it 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 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

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 (Atmospheric Radionuclide Transport Model, ARTM).

ARTM Specification

  • 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) 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 turbulence parametrisation) for licensing-related and retrospective applications provides for more flexible and realistic modelling

The picture shows the air Cesium-137 activity at constant output over 24 hours ARTM-Model: Average ground-level daily air activity of Caesium-137ARTM-calculated average ground-level air activity from constant daily Caesium-137 discharge of one Becquerel per second at ground level

ARTM Functionality

  • Meteorological conditions with a time series for mean hourly values or four-dimensional dispersion statistics
  • Orographically structured terrain and buildings with an upstream wind field model
  • Non-uniform emissions on an hourly basis
  • Several sources, ground-level sources, point sources, line sources, area sources
  • Variable computation grid, nested grids
  • Dry and wet deposition
  • Graphical issuing of concentration, deposition and time series for chosen locations
  • Editing of model parameters

Additional functions compared to AUSTAL2000

  • 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 Rn-222 (post processor)
  • Selection from among 800 radionuclides approximately
  • Consideration of special properties of some "special" nuclides
  • Export of the results for field imaging in geo-browsers (kml-export)
  • Additional programs for processing of the output files (e.g. predefinition of excluded areas)
  • Special user interface for control and graphical outputs.
  • In addition, interfaces with the existing calculation guides SBG (Calculation Guidelines for Emergency Situations according to § 49 of the Decree for Radiation Protection) and AVV (General Administrative Regulation according to § 47 of the Decree for Radiation Protection - all in German) 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.
  • The radiation exposure is calculated using a separate dose module which takes into account the levels of concentration and deposition of the radionuclides involved as calculated using the ARTM dispersion software. 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 possible to make a separate revision of the respective software packages or incorporate alternative dose modules.
  • 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.

Dose Modul DARTM

The dose program DARTM developed at 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 levels of both the individual organ dose and effective dose for reference persons are calculated for a year's time.

Deviating from the calculation guides provided for by the AVV, the recent version takes into account soil accumulation for only one year's time instead of 50 years as stipulated in the AVV.

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.

Further Development

ARTM will be advanced. The process started in 2016. The main development aspects planned are:

  • Development of (multilingual) English version of the programme, including the manuals
  • Checking of input-data (errors in time series, problems with divergency due to orography) to avoid abnormal terminations
  • Possibility to demand mixing layer parameters
  • Multiple technical improvements in regards to calculation duration, operation mode, security and user interface
  • Extensive documentation of the programme handling
  • Graphical development of building dimension and excluded areas
  • Automatical implemention of the calculation for the vegetation period
  • Improvement of the outputs of the Radon-post-processor
  • Practical testing, workshops, support and internet presence

Scientific Background

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 make assessments of these radioactive substances by type and activity. Based on the balanced discharges, 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 using emission data related to the nuclear facility under observation and so-called "dispersion models" (such as ARTM). The latter ones are used to model the transport processes of radionuclides e.g. from the stack of a nuclear facility to the environment.

This calculation of the concentrations of radioactive substances in various environmental media is followed by use of a dose module (e.g. DARTM) appropriate to assess the radiation exposure of the public.

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.
State of 2017.07.05

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