A book on the nuclear fuel cycle
Nuclear Societies do not often publish books. But the Slovak Nuclear Society does - not too often, but it does. The latest publication in question is a comprehensive monograph describing the nuclear fuel cycle. It is entitled – yes, you guessed it – The Nuclear Fuel Cycle. Here is brief glimpse of what you can read in the book.
Nuclear fuel is the source of the massive amount of energy that is produced in nuclear installations. The production of uranium, its processing and introduction into the fuel elements, its exploitation in nuclear reactors, its use in the proper reprocessing of used fuel and its final disposal are the key individual phases that make up the nuclear fuel cycle.
Uranium is a natural element with an abundance of 4 ppm in the Earth’s crust. Although it might appear that a nuclear reactor is a highly sophisticated piece of equipment that emerged as a result of the turbulent developmental years of nuclear physics in first half of the 20th century, and that its research was stimulated and accelerated by World War II, it has a natural analogy that was actually formed about 2 billion years ago. Natural conditions in the region of Oklo (Gabon, Africa) meant that after abundant rains or floods, water penetrated into geological formations that contained high concentrations of uranium and began to play the role of neutron moderator. The content of U235 isotope in the uranium deposits at that time was much higher than today’s 0.712 %, so no enrichment was required. The preconditions for a sustainable chain reaction of thermal neutrons had been created and heat was produced until the moderating water evaporated. Half a century ago radiographers found unequivocal proof in the form of evidence of sintered minerals, as well as high concentrations of radioisotopes. These could only have existed as a consequence of a chain reaction of nuclear fission. High concentrations of radioisotopes from Oklo, like those we try to immobilise in fixed matrices and dispose of in deep geological depositories, can serve us as a source of knowledge that can help us master the safe management of spent nuclear fuel.
The Nuclear Fuel Cycle describes in detail the front and back end of the nuclear fuel cycle, even though the numerous steps in the fuel cycle are not all carried out in Slovakia, and even though the final disposal of spent fuel in a deep geological depository in Slovakia has not been yet decided upon. The book primarily focuses on fuel for power reactors of the VVER-440 type that are currently in operation in the Slovakia. Our aim is to maintain operational experience with the mentioned fuel, to determine optimal operation and to evaluate the significance of individual thermo-technical parameters.
Safe nuclear fuel handling is, in our opinion, extraordinarily important, as are its monitoring, temporary storage and the back end of nuclear fuel cycle. Ensuring optimal spent fuel management, including its potential reprocessing and final disposal, is an essential task not just for us but for Slovakia too.
Juraj Klepac, Slovakian Nuclear Society