Spent Nuclear Fuel in Use

Spent Nuclear Fuel in Use

Photo: http://www.freepng.ru

Rosatom has announced the launch of construction of a research molten-salt cooled reactor at the Zheleznogorsk mining and chemical plant. The process will take at least ten years. If successful, it will mean a revolution in the fields of energy and environment protection.

The most probable option for location is in the foothill section of the plant at the site of the machinery room of the underground nuclear cogeneration plant. The press-service of Zheleznogorsk plant says that a research reference installation will be created at the initial stage. Its goal will be to obtain data for designing a molten salt reactor with the capacity sufficient for afterburning of the so-called minor actinides (americium, curium and neptunium). It is these elements that make major contribution to the high-level radioactivity of what remains after spent nuclear fuel waste processing.

That is, the creation of a reactor of this type will help move forward significantly in addressing the issue of hazardous waste utilization and finding a way to develop them as far as possible. In addition, the location of the complex in the pit that used to house the underground cogeneration plant of the ADE-2 power-generating unit will facilitate the use a molten salt reactor as an energy source for the town, since the previously built supply lines are available. "A molten salt reactor was made public earlier as a pilot project of the plant and it got support from (state atomic energy corporation) Rosatom for conducting R & D for a feasibility study. Implementation of the project is moving over to practical steps now,” said the press service of the plant.

The fuel in a molten salt reactor the molten salt of metals rather than the traditional fuel assemblies. According to experts, the extraction of such minor actinides from spent nuclear fuel processing waste and their subsequent "burning" in the reactor will reduce the amount of the most dangerous radioactive waste. So far, all that can be done is burying them deep underground. Advanced technologies for deactivation of spent nuclear fuel will provide Russia with huge advantages in the international market. "This is an extremely challenging task,” says Andrei Kapliyenko, the Director General of еру Nikolai Dollezhal Energy Engineering Research and Design Institute. “There is no any such project anywhere else in the world so far. First we have to create a research reactor to test the technology. We will adjust it and move on to a large reactor with powerful parameters. It will take time but the idea itself is new for us, and we have to avoid any risks with it."

In general, the issue of molten salt reactors is not new. Experts recall that the first such units operating on thermal neutrons were developed in the USA back in the 1950s. However, the main task during the so-called “cold war” was to develop weapons-grade plutonium, while liquid salt systems have a different purpose. Also, spent nuclear fuel waste was produced in the amounts comparable to the current ones. That's why it was easier to dispose of it. And the American program was wound down. In Russia, theoretic studies on the subject started in the second half of the 1970s at the Kurchatov Institute in Moscow. The results of research confirmed the efficiency of salt reactors but after the Chernobyl disaster and in connection with the general stagnation of nuclear power engineering, works in this field were stopped, too.

Yet the main advantage of molten salt reactor is probably its ability to prevent huge accidents. At Chernobyl, there was a thermal explosion at high pressure. While in salt reactors, the pressure of the operating zone does not exceed one atmosphere. Therefore, in case of a breach of tightness, there will be no release of radioactive substances. Salt brine will simply go into a reserve tank and the fission reaction will stop. Accordingly, the temperature will also drop and all the waste will remain in the reactor room. In other words, a powerful release of radioactive substances is not possible. It would not be an exaggeration to say that the ability of a molten salt reactor to burn actinides will make an invaluable contribution to the future of mankind. Neptunium and americium have a half-life of hundreds of years. And twenty liquid-salt reactors will be able to process everything that has been accumulated by the nuclear industry in the last 50 or so years.

“With this type of reactor it becomes possible to close the burn-out cycle, namely, to process the accumulated spent nuclear fuel with a remarkable decrease of waste quantity,” Oleg Kozin, an associate professor of the techno sphere and environmental safety department of the

Polytechnic Institute in Krasnoyarsk, an affiliation of the Siberian Federal University, said in an interview with wek.ru. At the same time, the expensive and complicated process of manufacturing of fuel elements with the following processing operations is not necessary here. The spent nuclear fuel pools are also unnecessary. One more factor is the inexpensively produced energy since the efficiency of this type of reactors significantly exceeds that of traditional reactors due to the higher temperature. One more advantage: the use of uranium-238 and thorium-232 as fuel, the reserves of which will be sufficient for hundreds of years, while stocks of uranium-235 used for traditional reactors will suffice for about 50 years only. In fact, with a broad introduction of salt reactors, the nuclear power industry will switch over to other fissionable materials along with the processing of accumulated big amount of spent nuclear fuel. In the terms of time limits , given the current state of affairs, it will take at least 5-7 years to make a reactor and two more years to set it up. Everything depends on financing."