Integrated Measurement and Information System for monitoring of environmental activity (IMIS)

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After the nuclear reactor incident of Chernobyl, the measuring system IMIS (Integrated Measuring and Information System for Monitoring the Environmental Radioactivity and Detecting Emissions from Nuclear Plants) was implemented in Germany as a precaution against the effects of nuclear incidents or other radioactive contaminations of the environment and for the early measurement and evaluation of their radiological impacts. It is operated on behalf of the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV). Its legal basis is the Radiation Protection Act. The German Laws and the supporting regulations can be found on the internet site of BMUV (in German).

IMIS is a nationwide comprehensive measuring system which permanently monitors the radioactivity in all important environment media in the whole federal territory. The Federal Government and the federal states perform this task jointly: Federal authorities monitor the area dose rate, the long-distance transport of radioactive substances and their distribution in air and water; about 50 authorities of the states monitor the environmental radioactivity wherever radioactive substances may possibly deposit and enter into the nutritional chain of humans.

IMIS covers about 1800 stationary measurement stations which monitor the area dose rate in the natural environment. At approximately 40 sites, the activity concentration of radioactive substances is measured in air and precipitations. 12 of these locations are trace survey stations for monitoring of the ground-level air. The Federal water ways and inland waters rank among the monitored media as well as the North and Baltic Sea. The radioactivity in food, animal feed, drinking water, but also in residuals and waste water is permanently determined. All measuring facilities of the Federal Government and the federal states are connected via a computer-aided dataveillance system with the Central Federal Agency (ZdB) at the Bundesamt für Strahlenschutz (Federal Office for Radiation Protection) in Neuherberg near Munich where all measurement results are compiled, preprocessed, documented and made available to the Federal Ministry of the Environment.

In case a large-scale radioactive contamination of the environment occurs as a result of an accident, the number of measurements per day is drastically increased. On the basis of the measured data as well as of prognoses made available via IMIS by the Deutscher Wetterdienst (German Meteorological Service, atmospheric dispersion prognoses) and the Bundesamt für Strahlenschutz (radiological prognoses), the Federal Ministry of the Environment makes recommendations for the protection of the population or arranges for further protective measures to be taken.

Within the scope of IMIS, PTB is responsible for the:

• provision of activity standards for the calibration of measuring facilities,
• operation of one of the 14 trace survey stations for monitoring of radioactivity in ground-level air,
• calibration of reference materials,
• operation of a national reference measurement sites for the comparison of dose rate meters under the same natural environmental conditions.