Human life is connected with the constant generation of all kinds of waste. This is not only spent fuel, but also deteriorated household appliances, scrap metal, and even wastewater. People do not even suspect how toxic an ordinary rusty pipe, lying around for years near their home, can be toxic. Let’s understand where the radioactive wastes come from, and what kind of threat they pose.
First you need to understand the very concept of “radioactive waste.” In its simplest definition, it looks something like this – these are items and objects use of which functioning has ceased, and which radioactive contamination exceeds the limits established by international law.
As you know, it is used processes associated with certain types of physico-chemical reactions for the manufacture of any item. For example, you have a metal samovar, the radionuclide activity of which exceeds the permissible norms.
And this means that it is polluted and is no longer in use, no one brews tea in it and it gathers dust in the country attic. This type of facility can be safely attributed to radioactive waste. This applies to porcelain cups or carafes, which for some reason have deteriorated, no one uses them, and they have been peacefully coexisting for decades in the same cottage attic.
A special classification is practiced quite often, in some countries, according to which radioactive waste also means spent nuclear fuel, and the attitude to this type of waste is appropriate. It should be noted that some radioactive waste contains isotopes of plutonium and uranium, which in turn are capable of fission, therefore they are classified separately, given that these materials can be used for the manufacture of nuclear weapons.
What is radioactive waste (RW) made of?
There are enough sources for their creation, the main one is nuclear energy. A huge amount of all kinds of waste is used during the operation of nuclear power plants. These include:
- worn equipment;
- ventilation and filter systems;
- coveralls;
- various objects and equipment from the reactor core, and so on.
This list can be continued, while all its components will belong to one of three groups: fission fragments, transuranic elements and activation products. The initial large nucleus, having absorbed a neutron, decays into two parts as a result of the decay reaction.
Moreover, uranium-235 and plutonium-239, being the main isotopes, decay into asymmetric pieces in an atomic reactor. As a result of this, light isotopes are formed such as strontium, technetium, ruthenium, rubidium, and heavy – isotopes of iodine, cesium, barium, cerium. Most fission products break up in a relatively short period, from 5 to 15 days.
The main problem is the isotopes of cesium-137, the half-life of which is at least 30 years. Only after 300 years, its half-life will decrease by 1000 times, and until that time its destructive legacy will still be quite noticeable.
Alpha-Beta-Gamma – Radiation
These three types of radiation have varying degrees of penetration. Gamma rays are critically dangerous, the so-called high-energy electromagnetic waves, which are capable of being formed during various types of radioactive decay. They very easily and quickly penetrate the human body, and in order to protect yourselves, it is necessary to use heavy materials with high thickness and density, such as lead.
Transuranic elements are formed differently. Their occurrence is possible only in the case of sequential capture of several neutrons and provided that the nucleus has not undergone fission. Plutonium, americium, and other isotopes are formed in the process of conversion functions. For the above isotopes, the half-life is huge, for example, the half-life of plutonium lasts from 239 to 24110 years, in addition, they carry the risk of gamma radiation and have high heat release properties.
It is from the presence of transuranic emissions that it is not possible in the near future to return the territories of the Chernobyl exclusion zone to their usual economic activities. As mentioned above, for cesium-137 it is enough 300 years to reduce its presence by 1000 times, but for plutonium-239 ten half-lives will be at least 241 100 years. These are just cosmic figures, they need to be comprehended.
In principle, any object, if its operation is difficult or completely terminated, and it is contaminated with isotopes, can be attributed to radiation waste. Although, some of them are still subject to decontamination. For example, a decontamination solution can be made with the help of special washing compounds by which it is possible to remove radiation isotopes from the surface of items or objects.
If we take a well-known samovar and try using a decontaminating agent to wash its inner and outer surfaces, then as a result we will remove the samovar from the category of radioactive waste, while receiving liquid radiation waste in the form of water diluted with detergent with which the samovar was washed.
It is also worth noting that items and objects can be contaminated by means of penetration of radionuclides of natural origin onto their surface. This applies to drill rigs subject to pollution as a result of their use in soil rocks containing uranium, thorium, and radium. The same applies to porcelain products made from similar clay rocks – the place of clay extraction is of great importance.
A number of special events are held in Ukraine in order to bring domestic standards for the classification of radiation waste to the standards of the IAEA requirements and bring them closer to the international scale.
What is the idea of this work? First of all, this is necessary in order to distinguish between types and correctly determine the options for disposal of various types of radioactive waste – the order and depth of their disposal depends on this. It will help rationalize the costs for finding sources of allocation of funds for burial, the search for special places for this, and at the same time ensure the conditions for their safety.
In a word, radiation waste requires greater attention – both are from the state and from civil society.
