Thermoelectric generator with radioisotope

A thermoelectric generating with radioisotope , (in English RTG: Radioisotope thermoelectric generator ) is a electric Générateur of simple design, creating electrical energy by radioactive Decay.

Such systems use radioactive materials (like the Plutonium -238), which generate Chaleur while radiating in nonradioactive materials. Heat is then converted into electricity by Thermocouple S by using the thermoelectric effect. The principal applications of the generators to Radioisotope are the food of the space probes and the lighting of some isolated Phare S.

Design

In comparison with other nuclear equipment, the principle of a generator with radioisotope is simple. It consists of a robust container filled with radioactive material, bored holes where are laid out of the thermocouples, the other end of the thermocouples being connected to a Radiateur. The Calorie S crossing the thermocouples is transformed into electricity. A Thermocouple is a device made up of two kinds of conducting metals, which are connected in closed loop. If the two junctions are at different temperatures, an electric current is generated in the loop.

Radioactive metal used must have a rather short Demi-vie, in order to be able to produce energy sufficient. One chooses Demi-vie S about a few tens of years. It is often about Plutonium-238, in its oxidized form (PuO₂).

Use

As in extreme cases of our planetary system, the radiation is insufficient to use solar panels, the space probes which must go there are equipped with generators with isotope: To travel 1, To travel 2, Galileo, Cassini, or New Horizons. A thermoelectric generator with radioisotope is particularly well adapted to the production of a stable power supply, over one long life, and to maintain for several years operational the instruments embarked in the interplanetary probes which circulate by enduring a considerable cosmic cold. For example, the generator embarked on the probe New Horizons is able to provide a stable power supply of 200 Watts on more than 50 years. At the end of two centuries, the power falls to 100 Watts. It should however be noted that because of the considerable quantities of Plutonium enriched present in a space GTR, any anomaly on the takeoff of the vectors used to propel the probe presents an environmental risk préocuppant. According to the estimates of worst of the cases, a repercussion of New Horizons at the time of takeoff, on inhabited areas, could have led to the figure frightening of 200.000 dead.

The generators with isotope were mainly designed for space exploration, but the Soviet Union used them to feed from the Phare S, which is not without posing environmental problems.

Safety

The generators with isotope do not function like the nuclear plants. The power stations create energy starting from a Chain reaction in which the Nuclear fission of an atom releases from the Neutron S, which in their turn involve the fission of other atoms. This reaction, if it is not controlled, can quickly grow exponentially and cause serious accidents, in particular by the cast iron of the Réacteur.

Inside a generator with isotope one uses only the natural radiation of materials radioactive, which excludes a priori any scenario catastrophe. The fuel is in fact consumed in a slow way, that produced less energy but this production is done over one long period.

Even if the risk of major catastrophe is quasi null, one is however not safe from a radioactive contamination: If the launching of a space probe fails at low altitude, there is a risk of contamination located, just like in the upper atmosphere, a disintegration of the probe could generate a dissemination of radioactive particles. The dangerosity of such an accident is prone to controversy, even if all the Sonde S carrying of the Plutonium until made a success of their launching today.

External bonds (in English)

Article on the safety of the generator used for the Cassini-Huygens mission.
a report/ratio on the use of the generators with isotope in the headlights.

Random links: