Some of my Physics Students at the Jagiellonian University: Piotr, Krzysztof, Karol, Lila, Pawel, Mariusz, Szymon, I, Pawel & Krzysztof. Behind the camera: Przemek.
Time has come to present to you, global English learners, some pieces of writing signed by some of my Physics students. As this blog develops I am glad to include as many such scientific pieces as possible.
Here’s an interesting paper signed by Piotr (the first on the left-hand side in the photo, barely visible).
Read the essay below, his take on ways of dealing with toxic waste.
By Piotr Czarnik
Radioactive waste is probably one of the most feared types of waste. One of the reasons why this situation is a common belief is that radioactivity is a phenomenon occurring only as the result of human activity. In fact, radioactivity is a natural property of some substances, and as such, it is quite common. It is connected with the instability of atomic nuclei (only a part of which have this property) which could emit particles capable of the damage to or even the destruction of cells. Radioactive nuclei, which are called radioactive isotopes by physicists, naturally occur in rocks, the walls of our houses, in food, and, eventually, even in our bodies. UNSECAR calculated that in 2000 natural radiation (measured by effective dose per capita) absorbed by our bodies was 6 times larger than the radiation produced by man-made sources. Among them the most significant were diagnostic medical experiments. The effective dose coming from radioactive waste was less than 1 percent of the total effective dose. In spite of its small impact on our health, which is a result of high standards of security used during process of their storage, its utilization poses a severe problem.
Radioactive waste, which has the highest level of radioactivity, is produced by nuclear reactors in nuclear plants. The nuclear fuel used contains a high percentage of radioactive isotopes of uranium or plutonium. After some time it becomes unsuitable for use because of the toxic byproducts of the reactor. Nevertheless, it is still highly radioactive, just like the toxic byproducts themselves, which have a large half-life span. The term half-life refers to the time period in which half of the nuclei in an isotope will decay. Because the reactor produces isotopes with a long half-life, it was estimated that the waste produced would be potentially dangerous even after a million years. Moreover, this waste contains a lot of plutonium, which is a basic material used to construct an atomic bomb. The extraction of plutonium from this waste is a very difficult and dangerous task, one that requires advanced technology. However, it is possible.
The properties of nuclear waste described above make the process of storage or utilization of waste extremely important. Before beginning the process of the storage in its final destination, it should be transformed into a form which could not react with the environment. There are propositions as to how this process should look, but there is not a common agreement on which of them should be commonly used and if they are sufficiently safe. One of them is a process of synthetic rock (Synrock) production during which radioactive isotopes become minerals. After that process nuclear waste should be stored in a safe place. One of the most realistic propositions is storing it in geologically inactive formations, 500 – 1000 meters below the surface of the ground, in old mines or drills made for that purpose. Another very interesting proposition is storing it in subduction zones in which tectonic plates sink into the Earth’s mantle, which could provide its permanent removal from our environment. Another possibility is its storage in outer space, but it is temporally impossible because of the high rate of rocket launches failure. Another interesting approach dealing with nuclear waste is its transmutation into non-radioactive isotopes in specially designed reactors. This method provides its total utilization.
The question of how to deal with radioactive waste efficiently and safely is still unanswered. Continous progress in science and technology and a lot of interesting ideas which was proposed give us hope that an answer will be found in the near future. Paradoxically, dealing with this kind of waste, because of its special character, could be much easier than dealing with more common types of pollution, which, are in fact, causing more casualties than nuclear waste.
Filed under: 6►THEME CHEST, ■ Physics, ■ Science & Technology, ■ Writing Samples