Radiation

BIOLOGY

INTRODUCTION:
Having to do a research about radiation and its consequences on the human body, it was thought immediately in the recent accident at the Fukushima which has been recognized as a nuclear accident at level seven, matching the disaster at Chernobyl in 1986.
The present work attempts to compare the consequences of the radiation emitted in the accidents of the nuclear powerplants above mentioned, on the human body immediately. But also knowing the consequences after twenty-five years of the Chernobyl accident we will attempt to identify possible consequences of the recent accident in Japan in a few years on the human body.
THEORICAL FRAMEWORK:
Radiation:
Radiation is a process in which energetic particles or energy or waves travel through a medium or space. Thereare two distinct types of radiation; ionizing and non-ionizing. The word radiation is commonly used in reference to ionizing radiation only (i.e., having sufficient energy to ionize an atom), but it may also refer to non-ionizing radiation (e.g., radio waves or visible light). The energy radiates (i.e., travels outward in straight lines in all directions) from its source. This geometry naturallyleads to a system of measurements and physical units that are equally applicable to all types of radiation. Both ionizing and non-ionizing radiation can be harmful to organisms and can result in changes to the natural environment.
Ionizing radiation:
Radiation with sufficiently high energy can ionize atoms. Most often, this occurs when an electron is stripped (or 'knocked out') from an electronshell, which leaves the atom with a net positive charge. Because cells and more importantly the DNA can be damaged, this ionization can result in an increased chance of cancer. An individual cell is made of trillions of atoms. The probability of ionizing radiation causing cancer is dependent upon the dose rate of the radiation and the sensitivity of the organism being irradiated.
In the nuclearpower stations the fission of the uranium in the core of a reactor produces dozen of residues that issue electromagnetic radiation and can affect the human health according to the type, the quantity and activity of the radioactive elements and the distance in which we are.

Alpha
1. Alpha radiation is not able to penetrate skin.
2. Alpha-emitting materials can be harmful to humans if thematerials are inhaled, swallowed, or absorbed through open wounds.
3. A variety of instruments have been designed to measure alpha radiation. Special training in use of these instruments is essential for making accurate measurements.
4. Instruments cannot detect alpha radiation through even a thin layer of water, blood, dust, paper, or other material, because alpha radiation is not penetrating.
5.Alpha radiation travels a very short distance through air.
6. Alpha radiation is not able to penetrate turnout gear, clothing, or a cover on a probe. Turnout gear and dry clothing can keep alpha emitters off of the skin.
Beta
Beta-minus (β−) radiation consists of an energetic electron. It is more ionizing than alpha radiation, but less than gamma. The electrons can often be stopped with a fewcentimeters of metal. It occurs when a neutron decays into a proton in a nucleus, releasing the beta particle and an antineutrino.
Beta-plus (β+) radiation is the emission of positrons. Because these are antimatter particles, they annihilate any matter nearby, releasing gamma photons.
Neutron
Neutrons are categorized according to their speed. High-energy (high-speed) neutrons have the ability toionize atoms and are able to deeply penetrate materials. Neutrons are the only type of ionizing radiation that can make other objects, or material, radioactive. This process, calledneutron activation, is the primary method used to produce radioactive sources for use in medical, academic, and industrial applications.
High-energy neutrons can travel great distances in air and typically require...