The Integrated Measuring and Information System (IMIS)

After the Chornobyl accident, the methods for measuring and evaluating the data differed from one federal state to another, making it difficult to produce a unified situation report. There was a lack of unified procedures and a central body where the measurement data was collected and evaluated.

An essential part of the Precautionary Radiation Protection Act of 1986 was therefore the establishment and operation of a measurement and information system for radioactivity known as the "Integrated Measuring and Information System" (IMIS) and for which responsibility was assumed by the BfS.

IMIS is used to collect environmental measurements:

• air,
• food,
• animal feed,
• soil,
• drinking water,
• groundwater and
• waste

are sampled, measured and analysed.

In total, over 80 federal and state institutions participate in IMIS. In order to monitor the radiological situation at all times, the BfS has led the development of a routine and intensive monitoring programme that specifies what must be sampled or measured where, by whom and at what frequency.

As part of IMIS, there are currently some 1,700 BfS measuring probes in Germany that continuously monitor both artificial and natural environmental radioactivity. This ensures seamless and comprehensive monitoring of airborne radioactivity both on a routine basis and in the event of a radiological accident. The system indicates changes in the ambient radiation at an early stage and triggers an alarm in the event of heightened levels of radioactivity.

With the aid of the forecasting and decision support system RODOS (Realtime Online Decision Support System), the BfS promptly estimates the environmental contamination and the resulting human exposure to radiation across the entire area in case of an impending release of radioactive materials – for example, from a nuclear power plant.

The results from measurement data and forecast calculations contribute to a radiological situation report, which forms an important basis for action by the authorities in a radiological emergency.

Should an incident occur, decisions on measures to reduce human exposure to radiation must be taken quickly, especially in the early stages.

To this end, the German Commission on Radiological Protection (SSK) has, in collaboration with the BfS, compiled a catalogue of all measures to be considered. This catalogue of measures describes the civil protective and emergency measures, and analyses both their effectiveness and their advantages and disadvantages, such as feasibility and public acceptance.

Dose criteria for emergencies indicate what civil protective measures should be taken in the event of a radiological emergency – and the expected level of human exposure to radiation from which these measures apply. The dose of radiation to which a person would be exposed in a nuclear accident serves as the basis for evaluation.

Prior to the Chernobyl reactor accident, there were no unified dose criteria for emergencies, and a margin of discretion was assumed. The process of dealing with the consequences of the Chernobyl accident highlighted the need for unified nationwide reference levels in an emergency.

As a result of the Chernobyl accident, therefore, specific dose criteria were defined for evacuation, the sheltering of people in buildings, and the taking of iodine tablets. At doses above the dose criteria for emergencies, the measures must be implemented wherever possible. Below, the measures must be discussed from the point of view of proportionality. Human exposure to radiation should be kept as low as possible.

The lack of legal regulations in the aftermath of the Chernobyl reactor accident also meant that inconsistent limit values applied to food and animal feed in Germany. As a result of the accident, the European Community introduced maximum values for caesium-134 and caesium-137, strontium-89/90 and plutonium. For example, these apply to:

• milk, dairy products and baby food,
• other foodstuffs such as meat and vegetables.

A nuclear accident can result in the release of radioactive iodine. If it is inhaled or enters the body via food or beverages, it may accumulate in the thyroid and encourage the development of thyroid cancer.

There was a particularly marked increase in the incidence of thyroid cancer in children in Belarus and Ukraine in the years following the Chornobyl reactor disaster. This led the German Commission on Radiological Protection (SSK) to re-evaluate the radiation risk for this form of cancer and consequently to lower the intervention reference levels for the distribution of iodine tablets significantly.

In order to be able to carry out disaster control measures such as evacuations effectively in an emergency, they must be planned in advance. To this end, so-called planning zones have been established in the vicinity of nuclear power plants.

After the reactor accident in Fukushima, Japan, in March 2011, the BfS examined the question of what effects an accident in a German nuclear power plant with a similar course of events to Fukushima would have in Germany (BfS report SW-11/12). This investigation was continued between autumn 2012 and the end of 2013 with more than 5,000 additional case studies. The detailed report (BfS Report BfS-SCHR-55/14) was published at the end of February 2015.

The BfS findings were directly incorporated into a recommendation by the Commission on Radiological Protection (SSK), which recommends extending the existing planning zones for emergency protection in the vicinity of nuclear power plants. These were forwarded by the Federal Environment Ministry to the state authorities for further plannin

The "General Federal Emergency Plan" has been in force since 2023. It applies to various types of radiological emergencies in Germany and abroad, for example following accidents in a nuclear power plant or during the transport of radioactive materials. The emergency plan provides for planning scenarios for such events and regulates the following on this basis

• Criteria for protective measures,
• procedures for warning and informing the public and
• regulations for official cooperation and coordination in the event of a radiological emergency.

The emergency plan partially replaces existing planning documents.

The Federal Radiological Situation Centre plays a special role here. Its tasks include drawing up the radiological situation picture in the event of serious supra-regional emergencies, informing the population and giving them recommendations on what to do.

To supplement the general federal emergency plan, further special emergency plans are to be drawn up that regulate the emergency response in certain areas potentially affected by such emergencies. The federal states are also developing additional emergency plans to supplement the federal plans. Until these emergency plans come into force, numerous existing documents will continue to apply as provisional federal and state emergency plans.