Study Tour

At Magdeburg-Stendal University of Applied Sciences, the lead German partner in the RENO-TITAN project, the focus was on the fundamentals and practical aspects of radiation protection. A speaker from the Ministry of Science, Energy, Climate Protection and Environment of the state of Saxony-Anhalt first explained the ambient dose equivalent rate, the measure of external gamma radiation per hour at a specific location , measured in microsieverts per hour. Typical natural values ​​in Germany are around 0.1 microsieverts per hour and vary depending on the geology. Higher uranium and thorium concentrations in the rock lead to increased background radiation. Even short-term weather effects have an impact: rain washes short-lived radon decay products out of the air and can temporarily increase gamma radiation at ground level, while a continuous snow cover shields the radiation and lowers the measured values.

Building on this, the speaker explained the annual dose. In Germany, the average natural radiation exposure is approximately 2.1 millisieverts per year, primarily resulting from the inhalation of radon and its decay products. Terrestrial and cosmic radiation, as well as smaller contributions from food and drinking water, are also present. Man-made sources, especially from medical applications such as X-rays and CT scans, lead to a total average dose of 3.6 millisieverts per year. For additional doses received by the population from activities requiring permits, a guideline value of 1 millisievert per year applies. This additional value determines which technical measures are necessary, how monitoring is carried out, and which disposal methods are suitable. The ALARA principle applies : exposure should be kept as low as reasonably achievable.

The speaker also outlined the legal framework. This is based on the EU basic standards for radiation protection ( Directive 2013/59/Euratom ), which are implemented in Germany through the Radiation Protection Act and the Radiation Protection Ordinance . While the federal government sets the rules, the individual states are responsible for enforcement – ​​in Saxony-Anhalt, this is the State Office for Consumer Protection. For activities with potential NORM exposure, a dose assessment and documentation are mandatory; depending on the results, reporting requirements and protective measures may follow.

Using Saxony-Anhalt as an example, the speaker demonstrated the practical handling of NORM (Standardized Rationale for Radiation Protection) and natural radioactivity. For the radioactive noble gas radon, the state designates precautionary areas and uses a reference value of 300 becquerels per cubic meter for indoor spaces. One becquerel corresponds to one radioactive decay per second. If an elevated initial radon measurement is detected, a longer-term follow-up measurement and a building assessment are conducted. Simple steps are then implemented: sealing joints and cable and pipe penetrations, targeted ventilation, and balancing the pressure between the ground and the interior. Negative pressure in a building, for example, caused by a powerful exhaust system, can draw in radon-containing soil air. A secure supply of fresh air and controlled exhaust air mitigate this effect. If these measures are insufficient, active systems are used, such as subsurface extraction with a radon well. In this system, a suction shaft captures the soil air beneath the foundation slab and extracts it to the outside via a fan. This lowers the radon pressure under the building and significantly reduces its entry. The process concludes with a follow-up measurement to verify the effectiveness of the measures and, if necessary, fine-tune them.

A concrete example from the Altmark region, based on the German standard NORM (Standard for Radioactive Waste Management), is the former natural gas extraction. Deposits and sludge containing radioactive radium, polonium, and lead formed in pipelines and facilities. During maintenance and decommissioning, these substances are removed, radiologically tested, collected separately, and conditioned for safe disposal. The equipment components are cleaned by mechanical removal, high-pressure water, or chemical processes. Only when cleaned components fall below the permitted levels can they be reused or recycled. The Mansfeld region, with its copper shale mining, was discussed as a historical NORM example. Both the ore and the copper slag contain naturally occurring radionuclides. Because this slag was formerly used in road and waterway construction or as paving stones, gamma radiation levels in such locations can be slightly elevated.

In addition to official monitoring networks, citizen science can also make valuable contributions. The organization Safecast collects measurement data on ambient radiation on a voluntary basis and makes it available worldwide (CC0 license). This benefits the public, education, research, and government agencies, as the detailed spatial data meaningfully complements official networks. The goal is transparency and trust. Construction plans, such as for the bGeigie, a portable Geiger counter with GPS developed by Safecast, are also accessible. It is important to note that citizen science data does not replace official dosimetry, but with sound methodology and quality assurance, it can provide practical support.

Afterwards, the group visited specialized laboratories at Magdeburg University, including the building products laboratory and the hydraulic engineering laboratory. A barbecue on campus in a relaxed atmosphere, which was very much appreciated by the Vietnamese guests, rounded off the day.

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Further introductory materials

Videos about radon (German)