Radioactive radiation
Shelters/nuclear shelters must be able to withstand the effects of modern weapons , i.e. they must offer protection against nuclear, biological and chemical weapons as well as close-range hits from conventional weapons .
The following describes the dangers posed by radioactive radiation and explains the protection options provided by shelters and bunkers.
Dangers from radioactive radiation
Ionizing radiation
Radioactive substances emit ionizing radiation. Ionizing radiation and radioactive substances are used and artificially produced in medicine, research and technology, and in the use of nuclear energy. Ionizing radiation includes electromagnetic radiation (X-rays and gamma rays) and particle radiation (e.g. alpha, beta and neutron radiation). [ 22 ]
Video: What is radioactivity? ( BfS - German Federal Office for Radiation Protection )
How does ionizing radiation work?
When ionizing radiation hits the human body, it can cause damage to individual cells or tissues. This is because the radiation energy can break apart chemical compounds (molecules) and also knock individual electrons out of compounds. The radiation can therefore directly damage biomolecules in the cell, such as proteins or DNA (which carries genetic information). [ 23 ]
The damage caused by ionizing radiation is divided into:
Deterministic radiation damage
Stochastic radiation damage
Table 21: Comparison between deterministic and stochastic radiation damage [ 23 ]
What are the dose limits?
The dose limits are set out in the Radiation Protection Act and the Radiation Protection Ordinance for the general population. Dose limits do not serve as a dividing line between dangerous and harmless radiation exposure.
Exceeding a limit value means that the probability of health consequences (in particular cancer) occurring is above a level defined as acceptable. [ 24 ]
Important limits and typical dose values in comparison
To classify the limit values, the German Federal Office for Radiation Protection (BfS) has listed important limit values and typical dose values (effective dose in each case) for comparison in the following table.
Table 22: Comparison of important limits and typical dose values [ 24 ]
Important thresholds for deterministic radiation effects
The following table contains some threshold values for acute radiation damage (deterministic radiation effects) to enable the classification of dose and limit values.
Table 23: Important thresholds for deterministic radiation effects [ 24 ]
Further detailed information on the subject of radiation can be found on the website of the Federal Office for Radiation Protection (BfS).
Link to website: www.bfs.de
Where can current measurement data be obtained?
The Federal Office for Radiation Protection (BfS) routinely monitors natural radiation exposure in its gamma local dose rate (ODL) measuring network with around 1,700 ODL measuring probes.
The measured local dose rate (ODL) is given in microsieverts per hour (μSv/h) . This corresponds to the ambient gamma radiation per hour at a specific location. The measurements are taken around the clock, 365 days a year.
Please note:
Unit of the limit values listed above: Milli sievert ( m Sv)
Unit of the current measurement data: Micro sievert per hour ( μ Sv/h)
Conversion: 1 milli sievert ( m Sv) = 1,000 micro sievert ( μ Sv)
Measuring points in Germany [ 25 ]
The ODL measuring network has an important early warning function in emergency preparedness in order to quickly detect increased radiation from radioactive substances in Germany.
If a radioactive cloud of pollutants spreads, it could be tracked almost in real time. This is an essential prerequisite for initiating targeted measures to protect the population at very short notice.
The current measured values are displayed on the website of the Federal Office for Radiation Protection ODL-Info .
Information about a measuring point, as well as a link to the current time courses of the ODL at the individual measuring points, can be obtained by clicking on the desired station in the map or in the measuring point list. [ 25 ]
Example extract of the gamma dose rate map [ 25 ]
How can you protect yourself from radiation?
There are different types of radiation. Gamma radiation is the most harmful ionizing radiation and the most difficult to shield against. Gamma radiation has the same physical nature as visible light, but is considerably more energetic and has a high ability to penetrate matter.
Heavy materials such as lead or concrete must therefore be used to shield against gamma radiation. [ 26 ]
For this reason, both the ceilings and the external walls of the protective structures must have sufficient component thicknesses to provide protection against nuclear radiation. In the shelter design, protection against nuclear radiation is provided by shielding, whereby the protection factor depends on the thickness h and the density ρ of the component.
Minimum component thicknesses for shelters
For both ceilings and walls of the protective shell, a minimum component thickness must not be exceeded:
• Minimum ceiling thickness: 300 mm
• Minimum external wall thickness: 300 mm
