Everything you need to know about radioactivity
Everything you need to know about radioactivity
Did you know that we are surrounded by natural radioactivity? And that our bodies are themselves radioactive? In addition to this natural phenomenon, there is also artificial radioactivity, which is found in medical and industrial applications that use nuclear technology. In both these fields, everything is strictly regulated and rigorously measured. Our country does not have a problem with overexposure.
What is radioactivity?
Radioactivity is a natural phenomenon. It results from spontaneous changes that occur within atoms, when they release excess energy in the form of what is known as ionising radiation. Natural radioactivity comes mainly from the ground and from cosmic radiation from the Sun and the Big Bang. Every time we breathe or eat, we come into contact with natural radioactivity. We also inhale natural radionuclides. Radon, a radioactive gas found throughout the soil, is the main source of exposure through inhalation, accounting for around 40 per cent of the total. Due to the composition of the soil, radon concentrations in the south of Belgium are higher than in the north.
For medical and industrial purposes, humans have created artificial radioactivity. This includes, in particular, medical imaging, but also the burning of coal or the use of phosphate fertilisers, which produce significant amounts of it. Nuclear power generation, meanwhile, accounts for a tiny fraction of artificial radioactivity (less than 0.001 microSieverts per year). The average exposure to ionising radiation per capita in Belgium is 4 mSv per year. The diagram shows the various sources of radioactivity.
(Source: AFCN website)
How can radioactivity be identified and measured?
Radioactivity is easy to detect and measure. Whether natural or artificial, its characteristics and effects are similar. The radiation to which we are most exposed results from natural radioactivity (55 per cent) and medical applications (45 per cent).
In Belgium, radiological monitoring of the country is carried out 24 hours a day thanks to the TELERAD automatic monitoring network. Sample collection and analysis supplement these data. This dual approach enables specialists to measure natural and artificial radioactivity in the air, rainwater, groundwater and drinking water, as well as in river beds and sediments, along the coastline and, finally, in products from the food chain (dairy products, meat, vegetables, etc.).
The first protective measure? Measurement.
The very first line of defence against radioactivity is to measure it, as we shall see in detail later. To ensure targeted protection, two limits on the annual dose of radioactivity have been set:
- The limit for the Belgian population (excluding natural radiation and the effects of medical imaging as a patient) is 1 millisievert per year.
- The limit for people exposed as part of their work is 20 millisieverts per year.
The Federal Agency for Nuclear Control (AFNC) is responsible for providing active and effective protection for the public, workers and the environment. Its monitoring and actions cover both natural and artificial radioactivity in a wide range of situations. The aim of radiation protection is, of course, to eliminate or minimise as far as possible the risks associated with ionising radiation.
Où suis-je exposé à la radioactivité et dois-je m’en inquiéter ?
In buildings and homes: watch out for radon
For a large proportion of the population, it is mainly radon in the home that affects the annual dose of radioactivity. Radon is a naturally occurring radioactive gas which, in the event of high exposure, can have harmful effects on health.
As radon enters buildings through the ground, the risk is determined by the composition and structure of the subsoil. It is therefore not the same throughout Belgium.
Radon is more prevalent in areas where the overlying layers of loose material are generally thin, because the rocks containing radon are closer to the surface. These areas are mainly located south of the Sambre and Meuse valley, in the districts of Verviers, Bastogne, Neufchâteau, Dinant and Marche.
The AFNC organises local awareness-raising campaigns, carries out measurements and offers monitoring services for buildings and homes. Regularly ventilating the air inside the home is a simple and effective first step. Next, you should ensure that the building is sealed to prevent radon from entering. If you would like to carry out a ‘radon test’ or obtain further information, please visit the AFCN website.
In the sky, close to cosmic rays
Cosmic radiation emits natural radioactivity. This is why the AFCN pays particular attention to the radiation protection of pilots and cabin crew. The measures apply to flight crews who fly for long periods and at high altitudes.
Are you exposed to radiation when you fly off on holiday? No, you can take off with peace of mind: you would need to spend at least a hundred hours on a plane to come anywhere near a dose of 1 mSv/year.
In medical diagnostics and treatments
On average, half of the total radiation dose received by a Belgian over the course of their lifetime comes from medical examinations. But of course, medical imaging and nuclear medicine are invaluable and essential.
Before prescribing examinations and treatments, doctors weigh up the benefits and risks. The doses administered are reported to the AFCN. The Ministry of Public Health has also drawn up recommendations for the responsible use of medical imaging techniques.
In industrial activities and nuclear power stations
The impact of industrial applications is insignificant. It accounts for less than 1/5000th of the total. Belgian nuclear power stations therefore have a virtually non-existent impact on the population and the environment. Moreover, the TELERAD monitoring network confirms that radioactivity levels are in no way higher in the vicinity of our power stations.
Nuclear energy, research, medical care, airport security checks and many other professional activities: thousands of people work with nuclear technology applications in Belgium every day. Very strict rules are in place to protect these workers. The aim is clear: to minimise radiation doses as much as possible and to ensure that the permitted limits are never exceeded.
Doel and Tihange have voluntarily set individual radiation doses at half the legally permitted levels, namely 10 millisieverts instead of 20 millisieverts per year. In practice, the average annual radiation dose to which staff at Doel and Tihange are exposed is 1 millisievert, which corresponds to the maximum annual dose for the general public.
