(nuclear power)
Nuclear electricity __ the density of isotopes (uranium 235) can be increased to produce electricity in it
Researcher and author: Dr. ( Afshin Rashid)
Note: It is possible to increase the density of uranium 235 isotopes in it. Nuclear power units that work with light water are usually operated with 2 to 5 percent of uranium 235. In a reactor, usually 3 types of resistance enrichment will be used simultaneously to equalize the neutron flux and produce uniform heat and energy .
So that during refueling during the operation of the reactor, the fuel with more richness is placed on the outer side of the fuel assemblies of the heart of the reactor, and after about 12 to 18 months, the next refueling is done and by placing new uranium, the spent assembly is removed from the center. The core of the reactor will be removed and the new fuel will move from the outer environment to the middle and the medium-rich fuel will occupy the place of the less-rich fuel. 43 will be created in 2 neutrons during each thermal fission , and if one of these neutrons remains for the fission of 1 neutron to be used next, 43 must be removed from the environment in nuclear reactors. But the point that is important is that the neutrons produced as a result of nuclear fission haveMev 2 (it is a different energy and their average energy is 21.6x10 - mega electron volts [each electron volt is equivalent to 19 joules of energy]), while uranium 235 reacts with neutrons whose energy is much lower than This value means about 25 thousandths of electron volts and their speed should be 2200 meters per second, and since the main fuel of reactors is uranium-type nuclei, so the energy of neutrons should decrease . The neutrons produced in the reactor, after being released , collide with the materials around the fuel and their energy will decrease due to these collisions, and if after the energy decrease, they collide with the fissile nucleus (Uranium 235), it will be absorbed. And it causes the next nuclear fission to occur.Of course, at this stage, neutrons may be absorbed by other elements in the reactor and removed from the reaction cycle.
If the material surrounding the fuel is made up of light elements, as a result of neutron collision with those materials, more energy is lost, which is the best and most available material for reactors . (D2O) and thermal heavy water (H2O), normal water If normal distilled water is used around the fuel rods of a nuclear reactor, the neutrons produced after 19 collisions can reach thermal energy and this amount for heavy water It will be 35 times, but at the same time, ordinary water absorbs a large amount of neutrons compared to heavy water, which will slow down further reactions , because only uranium 235 isotopes are able to react with thermal neutrons . Therefore, the absorption of neutrons causes the amount of the next reaction to decrease and the reactor to shut down. For this purpose, the amount of isotope 235 in nuclear fuel must be increased so that thermal neutrons collide with it before being absorbed by water and nuclear reactions take place. As a result, there is a need to enrich uranium. But because the percentage of neutron absorption by heavy water is much lower than normal water. Therefore, if we want to use normal uranium in the reactor, as a result , heavy water should be accumulated around the fuel rods, so as to slow down the speed of neutrons and without absorbing it, it is possible to encounter and absorb thermal neutrons by uranium 235.
Conclusion:
It is possible to increase the density of uranium 235 isotopes in it. Nuclear power units that work with light water are usually operated with 2 to 5 percent of uranium 235. In a reactor, usually 3 types of resistance enrichment will be used simultaneously to equalize the neutron flux and produce uniform heat and energy .
Researcher and author: Dr. ( Afshin Rashid)
Specialized doctorate in nano-microelectronics