Mystery of the failed measuring point solved

Green Councilor Daniela Rieth brought a few questions to ask when she visited FRM II in March. One was about a measuring station in Garching that records the local dose rate and had been out of action for several months. The mystery surrounding this probe has now been solved: it is operated by the Federal Office for Radiation Protection (BfS) and has been measuring again since March.

Michael Schmidt, head of the radiation protection department at FRM II, with a mobile measuring device for detecting radiation. © Bernhard Ludewig, FRM II / TUM

Michael Schmidt, head of the radiation protection department at FRM II, with a mobile measuring device for detecting radiation. © Bernhard Ludewig, FRM II / TUM

The Green city councilor’s questions (see the press release from 12 March) about the Heinz Maier-Leibnitz Research Neutron Source (FRM II) were taken up by the Greens in the Bavarian state parliament and sent to the State Ministry of Science and the Arts in an inquiry. These have now also been officially answered. The measuring stations of the FRM II and the State Office for the Environment were unaffected by the outage, which lasted several months: “There was only one prolonged technical failure during this period (12 hours, end of December 2023),” the answer states.

BfS measuring station was out of operation from May 2023 to March 2024
The Federal Office for Radiation Protection (BfS) operates an independent network of probes throughout Germany that measure natural radiation exposure. This includes a station in Garching which, according to the website, did not record any measured values from 24 May 2023 to 10 March 2024.

Protection from groundwater
The issue of high groundwater levels, which affected many buildings in Garching, has now also been answered in detail in writing in the responses to the parliamentary inquiry: “Neither a building of the FRM II nor a building of Forschungszentrum Jülich was affected by the high groundwater level.”
The reactor building is also particularly protected against high groundwater levels: “The reactor building […] forms a common basin with the basement area under the neutron guide hall. […] It is elevated to -1.70 meters. The highest possible groundwater level is approx. 1.8 m below ground level (this provides a 10 cm buffer). All connections (e.g., pipelines, sewer ducts) in the buildings around the groundwater seal are designed to be pressurized water-tight,” the answer states. Further: “At the FRM II, the spent fuel elements are stored in the settling pool in the reactor hall (fuel element storage pool). The lower edge of the settling pool is at a height of +4.6 meters above ground level. This means that high groundwater levels do not affect the settling basin.”
“We are pleased that all questions have now been clarified and all measuring stations are reliably in operation,” says Michael Schmidt, the head of the department responsible for radiation protection at FRM II.