| Ever since the beginning of the nuclear age, radioactive waste has found itself being taken across continents and oceans in order to find a place at which it might be dumped. Most countries in the world do produce at least some nuclear waste. It can remain harmful for thousands of years. With all of this understood, no country can seem to agree on precisely how this waste should be disposed of at this point in time. There are now interim storage systems in place where nuclear waste sits for 30 to 40 years. Even after this time period, the waste remains dangerous and needs permanent storage.
Recycling of nuclear weapons:
Waste from the recycling of nuclear weapons (unlike its production, which demands primary raw materials from a reactor fuel) does not contain sources of beta and gamma rays with the exception of tritium and americium. Tritium and americium contain a much bigger number of actinoids, emitting alpha rays, such as plutonium-239, which is exposed to the nuclear reaction in bombs and also some substances with huge specific radioactivity such as plutonium-238 or polonium.
In the past, beryllium and highly active alpha radiators such as polonium were suggested for use as the Inuclear charge in bombs. Now, the replacement of polonium is plutonium-238. Due to state security reasons, the detailed designs of contemporary bombs are not covered in literature accessible to wide range of readers.
Some models also contain radio isotope energy sources, in which plutonium-238 is used as long-term electric power source for the working of the electronics of the bomb.
Probably, the disintegrated substance of an old bomb, which is to be replaced, contains plutonium isotopes fission products. Alpha-radiating neptunium-236, formed from plutonium-240 inclusions and also some quantity of uranium-235, obtained from plutonium-239 belong to plutonium isotopes fission products. The quantity of the waste of radioactive nuclear fission of bombs will be very little and in any case, they are much less dangerous (even if translated to radioactivity as such) than plutonium-239.
Americium-241 is formed as a result of the beta disintegration of plutonium-241 and an increase in quantity of americium is a big problem more than the disintegration of plutonium-239 and plutonium-240 since americium is a gamma radiator (its external influence on workers increases) and an alpha-emitter, capable of releasing heat. Plutonium can be separated from americium by various methods, among which - pyrometric treatment and extraction by means of a water/organic solvent. The modified extraction technology of plutonium from irradiated uranium (PUREX) is also one of the possible separation methods.
Physics:
The radioactivity from all waste from the nuclear industry decreases in the due course of time. All radioisotopes, contained in radioactive waste, have a half-life period – time period, for which radionuclide loses half of the radioactivity; with time, all waste disintegrate in non-radioactive elements. Some elements (for example, plutonium-239) in discharged fuel remain dangerous to human beings for hundreds and thousands of years, others - for millions of years. Thus, these radioactive wastes should be isolated from the environment for hundreds and thousands of years. Some elements, for example iodine-131, have short half-life period (in the case of iodine - 8 days) and hence cease to pose danger much more quickly than other long-living isotopes, however their activity is much higher initially.
The faster the radioisotope decays, the more radioactive it is. The energy and type of the ionizing radiation, released by pure radioactive substances, are important for determining the degree of hazard. The chemical properties of radioactive elements define how easily it can get into the environment and affect the human body. This issue becomes complicated since many radioisotopes decay up to an unstable condition and can form into radioactive fission products through the same decay chain.
Biochemistry:
Depending on the disintegration form and the biochemical element, the hazard due to the affect of radioisotopes varies. For example, iodine-131 — is a short-lived beta and gamma emitter, but since it accumulates in the thyroid gland, it is capable of causing more damage than TcO4, which being soluble in water, quickly comes out along with urine. Similarly, alpha emitting actinoids and radium are extremely harmful as they have a big biological half-life existence and their radiation has a high level of linear energy transmission. Because of similar distinctions in rules, determining the harm caused to the organism, they greatly differ depending on the radioisotope and sometimes by the nature of the chemical compound containing a radioisotope. |
