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- 50 questions and answers about nuclear energy and our nuclear power plants
- Radioactive radiation
What is ‘radiation’?
Visible and invisible light, radio waves, heat, magnetic fields, etc. are all forms of ‘radiation’. In other words, radiation can be found everywhere. By radioactive and ionising radiation, we mean X-rays, alpha radiation, beta radiation, gamma radiation and neutron radiation. The properties of these different types of radiation can differ quite significantly. Some radiation can be blocked by just a bit of air; other types of radiation can penetrate thick walls. These properties depend on the wavelength of the ‘particle’ that is emitted by an unstable radioactive atom.
How is radioactivity created?
Atoms are the smallest particles of a chemical element that are chemically indivisible. Atoms are generally stable. Stability requires a balance between the numbers of different particles (protons and neutrons) in the nucleus. In some atoms, that balance is disrupted. Such unstable atoms are called radioactive. They emit radioactive (ionising) radiation until their surplus energy disappears and they are stable again. This process is called radioactive decay.
Unstable atoms occur everywhere in nature: in the air, in the soil - and even in building materials and foods. Some areas have more natural radiation than other areas. For example, radioactive radon gas is more prevalent in the Ardennes region than on the coast. There is natural background radiation in the areas where the Doel and Tihange nuclear power stations are located. Our activities in the nuclear power stations have no impact on radiation levels.
Is radioactive radiation harmful?
Radioactive radiation is high-energy radiation that has many useful applications. However, it can also cause damage to materials and to the human body. Whether or not radioactive radiation is dangerous depends on the type of radiation emitted by the radioactive source. The distance to the radioactive source and the duration of exposure to the radiation determine how dangerous it is. The same applies to the sun's rays.
How is radioactive radiation measured?
Radioactive radiation cannot be detected by the human senses. It is detected using a device called a Geiger counter.
Radioactivity in the environment is monitored via the federal government's Telerad network. Sensors are distributed across Belgium for that purpose. The results of these measurements can be consulted at www.telerad.fgov.be. In addition to this network, the Federal Agency for Nuclear Control (AFCN/FANC) continually analyses the radioactivity in the area around the nuclear power stations. In addition, ever year ENGIE Electrabel commissions the Belgian Nuclear Research Centre (SCK•CEN) in Mol to conduct external inspections. And every year, these inspections confirm that the Doel and Tihange nuclear power stations have no measurable significant impact on the environment or the population.
How do we protect our employees?
Since radiation can pose a health risk, the legal regulations are especially stringent. The change in the radiation dose to which people are exposed is closely monitored. Special attention is paid to subcontractors who have already worked in other nuclear power stations.
The Sievert (symbol Sv) is the unit of ionising radiation dose to which a person is exposed in a given period. A citizen may be exposed to a maximum radiation dose of 1 milliSievert (mSv) per year. For anyone who must come into contact with radiation for work-related purposes, the legal standard is 20 mSv per year. For all internal and external employees, ENGIE Electrabel's allowable maximum dose at its nuclear power stations is half of the legal dose, i.e. no more than 10 mSv per year.
What is the difference between ‘contamination’ and ‘irradiation’?
There are various ways in which a body can be exposed to radioactive radiation. A radiation source located outside the body is called 'external radiation'.
Radioactive particles found on the skin or in clothing fall under the 'external contamination' category. Such contamination can be prevented by simply wearing a protective suit. Radioactive particles can be removed relatively easily by washing. If this is not done, the particles continue to emit radiation locally and could cause damage.
Internal contamination is created if radioactive particles are inhaled, swallowed or end up in the blood via cuts. Internal radioactive contamination can be prevented by using a face mask and washing your hands before eating.