Vladimir Shlyomin

U

ntil recently just specialists in nuclear power knew about such a thing as spent nuclear fuel (SNF). The term became used in everyday life in the spring of 2001, when the State’s Duma started debating amendments to the Laws "On Protecting Environment" and "On Using Nuclear Power". So, this was the way that the discussion of SNF was imposed on the apparently alarmed society, which heard a lot about the Chernobyl tragedy but knew very little about the nuclear industry. Sometimes the public debates developed into actions of protests. The most active participants crowded streets carrying memorial candles, handcuffed themselves to fences of nuclear power plants.
The major public indignation took place, when projects of receiving and reprocessing SNF from abroad were made known. By their demonstrations those, who are opposed to turning Russia’s territory into a "nuclear dump", strongly resemble European green peace activists with their protests against transporting nuclear materials from one country to another. Opponents are simply ignoring the fact that any nuclear power is inevitably facing the problem of maximum utilization of fissionable materials and has to solve it somehow.

The Russian Ministry for Atomic Energy has been trying to explain the public its position on bringing foreign spent nuclear fuel into the country.

RADIATION AND INVESTMENTS
Russia’s sources of SNF include ten nuclear power plants, nuclear submarines and surface ships of the Russian Navy, nuclear ice-breaker fleet as well as research reactors. As of today, their activity has resulted in accumulating over 14,000 tons of SNF.
As a whole, the world’s total figure stands at 250,000 tons of such a fuel. It is being disposed of in different ways. The U.S. is warehousing SNF, thus, putting off efforts to solve the problem till better times. France and the UK are reprocessing their own SNF and even receiving SNF from other countries, thus, making money on it. As for Russia, it still has been looking for an optimal option.
"Russia possesses all the necessary technologies, personnel, opportunities and enormous experience so as to fully reprocess SNF", believes academician Evgeny Velikhov. "Even with the absence of budget financing this problem can be solved. But it is necessary to learn how to attract appropriate investments".
Leaders and experts of the Russian nuclear industry regard arranging of the SNF reprocessing as the real source of funds, which could be used for solving many other problems of the nuclear industry as well. Among them, for example, are the needs for making investments in construction of more advanced and safe nuclear power plants, for taking large-scale nature-conservation measures, including those connected with eliminating aftereffects of radiation pollution of the past, for utilizing nuclear waste accumulated earlier. By estimates of analysts, bringing in 20,000 tons of SNF from abroad and storing it for 10 years would let Russia make about $20B. However, the outlook for reprocessing SNF is also good since there are no less opportunities.
The spent nuclear fuel has practically all the unspent fuel potential: it contains 95% of uranium-238, 1% of uranium-235 and 1% of plutonium-239. That is why it would be more proper to consider SNF a secondary resource. After going through the fuel cycle at nuclear power plant, regeneration and re-fabrication it may become good for being used anew. By its generating value the fuel produced from 20,000 tons of SNF can be compared with 410 to 470 million tons of oil or with 630 to 730 billion cubic meters of gas. And this is calculated on the basis of technologies, which have already been in use at nuclear power plants.

THE LONGER THE STORAGE, THE LESSER THE HAZARD
The nuclear fuel is a reliably insulated radioactive material being included in fuel elements (FES). Their containment shells are designed for operation in extreme conditions of reactor’s fissile zones. The temperature at the center of fuel elements exceeds 1,000 degrees. Fuel rod arrays of FES in the aqueous or vapor aqueous medium are subject to high pressure (from 70 to 140 atm) and vibration.
In the first months, as short-lived radionuclides keep decaying, the radioactivity and energy-release of SNF quickly fall down. Later, rates of the activity reduction become slow and in 3 to 5 years the fuel can be transported, reprocessed or transferred for a long-term storage. It should be noted that SNF is stored at all operating nuclear power plants posing no serious hazardous problems for plants’ personnel and for the general population in particular.
Conditions of keeping SNF after unloading from a cooling pond can be called comfortable as compared with those in the reactor’s fissile zone: impermeability, inert atmosphere, protection from exposure. This protection is provided by the package container. The standard demands of container strength are exceptionally high. While developing a container, analysis and calculation methods can be successfully applied to ensure its strength. However, in accordance with the rules of IAEA the process of securing its strength does not end up with it yet.
Containers’ bench-tests include: their fall on the absolutely hard surface from the height of 9 m at the most critical angles, the fall on pin, endurance in fire-zones. Appropriate test benches are available in Russia as well.
As far as the transportation safety is concerned, it is a fact that during the whole history of the nuclear industry not a single accident has happened while transporting SNF.
The physical and chemical characteristics of nuclear fuel also contribute to ensuring its safety. The fuel is contained in the so-called fuel matrix, which, in its turn, is included in the impermeable fuel rod arrays of FES, which is surrounded by walls of load-carrying structure. Even if the fuel rod array is mechanically destroyed, no conditions for spreading the most of radioactivity in environment emerge.
During a long-term storage the product fission activity goes down, although rates of reduction in activity of caesium and strontium, the main fission products, are small (30 years). Nevertheless, the lengthy technological retention pushes the decay of some radionuclides, which do not make any significant contribution to radioactivity but complicate reprocessing SNF. That is why, the longer the storage period, the simpler the SNF reprocessing.
As SNF is being reprocessed, there happens a release of components, such as uranium, plutonium, some fission products, which are valuable for obtaining isotopic products. After regeneration and re-fabrication the major portion of fuel rod arrays gets back in the nuclear fuel cycle and economic use. And only a small part of real radioactive waste is not subject to further utilization.
The final stage of handling waste includes rejecting it, encapsulating in high-strength (obtained through glazing, bituminizing or other ways) matrixes and burying it in reliable geological formations.
Precisely such technologies are being used in Russia, which after correcting a number of federal laws will be capable of providing much more services to handle SNF of the foreign origin.

SAME AS FIVE HOURS OF ORDINARY LIFE

Fuel rod array (FRA) to produce nuclear fuel for reactors

"Some say that Russia will be heaped up with nuclear waste. It is highly naive", says Alexander Rumyantsev, the Russian Minister for Atomic Energy, when commenting on arguments of opponents. Stressing that the case in point is a safe storage in accordance with the rules of the national and international control, the Minister reminds that the amount of SNF being brought into Russia is limited: no more than 20,000 tons till 2020 to 2025. And even in this case the radioactivity of all SNF being stored in Russia will be twice as low as in the U.S. and lower than in France or Japan.
"It is a very profitable and well-established business. And we will have to fight for our share of the market. If we succeeded in squeezing our competitors and reprocessed at least one tenth of waste, we would get enough funds to improve ecology and reprocess our own domestic SNF four times as much", explains Rumyantsev.
The preliminary technical and economic as well as marketing studies showed that in case of bringing the planned amount of SNF in Russia it would be necessary to spend $2.6 billion on setting up an additional infrastructure and the cost of storing, reprocessing and utilizing waste would reach $7.8 billion. The most part of these expenses will have to be made in 20 to 30 years after having the fuel brought in and getting the funds. But, on the other hand, it would already become possible to direct during that period up to $10B to finance ecological programs, regions’ needs as well as to make budgetary allocations.
Under the plans of the Ministry for Atomic Energy, SNF will be stored at one of the industry’s enterprises for 30 to 50 years. After that, when the biggest amount of fission products decays the natural way, some portion of fuel will be returned to suppliers and the other one will be regenerated and used in the nuclear fuel cycle.
According to the concept adopted in Russia, SNF is subject to reprocessing. Products received as a result of reprocessing are used for producing fresh nuclear fuel (uranium, plutonium), are utilizes in different industries and medicine (isotopes). That is why SNF is not considered a radioactive waste.
"Indeed, from the technical point of view, SNF is not a waste", says Tero Vajoranta, the director of the radioactive waste department of the Radiation and Nuclear Safety Authority of Finland. In his words, "however, in accordance with their laws or national policies some countries place the spent fuel among the radioactive waste". For many years Finland has been using Russian technologies safely and effectively. In Finland’s opinion, the Russian Ministry for Atomic Energy has the world’s most advanced technology of reprocessing the spent fuel and other nuclear materials as well as the unique experience of building and operating nuclear fast reactors. Constructing fast reactors, where fuel obtained from the spent one will be used in the first place, will allow to make the nuclear power engineering even cleaner and safer ecologically.
The available experience of handling spent nuclear fuel permits to figure out radiation risks with a high degree of accuracy. They are directly connected with the population radiation dose measured in SV/H. The population radiation dose received while handling 20,000 tons of foreign SNF will amount to no more than 250 SV/H. (this is a conservative estimate that does not take into account technological advances). But Russia’s population is receiving the same dose in just five hours of the ordinary life due to the natural setting and medical treatment procedures.