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Biography
Alexander Vasiliev
Prof. Alexander Vasiliev
Nuclear Safety Institute of the Russian Academy of Sciences (IBRAE); Moscow Institute of Physics and Technology, Russia
Title:  Application of New Perspective Materials as Advanced Tolerant Fuel Cladding Materials in Nuclear Reactors of Future Generation
Abstract:

Currently, the comprehension among the specialists and functionaries throughout the world is getting stronger that the nuclear industry can encounter serious difficulties in development in the case of insufficiently decisive measures to enhance the safety level of nuclear objects and to ensure clean energy and green world. The keen competition with renewable energy sources like wind, solar or geothermal energy takes place presently and is expected to continue in future decades. One of main measures of nuclear safety enhancement could be a drastic renovation of materials used in nuclear industry.

The analytical models of high-temperature oxidation of new perspective materials including chromium-nickel-based alloys, zirconium-based cladding with protective chromium coating, FeCrAl alloys and composite claddings on the basis of SiC/SiC in the course of design-basis and beyond-design-basis accidents at nuclear power plants (NPPs) are developed and implemented to severe accident computer running code. The comparison with available experimental data is conducted.

For example, the FeCrAl alloy and chromium have excellent characteristics of corrosion and oxidation resistance compared to zirconium both for the NPP normal operation temperatures and high-temperature conditions. It is very important for the nuclear safety including the resistance to design-basis and beyond-design-basis accidents at NPPs.

However, the worsening of FeCrAl cladding oxidation characteristics is reported when approaching the melting temperature of FeO (T=1371C). The formation of melt leads to acceleration of oxidation and hydrogen generation. Also, recent experimental data showed that in the temperature range close to upper limit of design-basis accident (T=1200C) and higher there is a considerable worsening of Zr/Cr cladding protective properties. In particular, a role of Cr-Zr interdiffusion with subsequent influence on degradation of protective properties is revealed.

The new advanced models of high-temperature oxidation FeCrAl, Zr/Cr, SiC/SiC and chromium-nickel  claddings are developed. In particular, the Zr/Cr cladding oxidation model is based on simultaneous solution of oxygen and zirconium diffusion equations in different layers of the cladding. A very important role of Zr outward diffusion to the interface between chromium oxide and metallic chromium resulting to severe degradation of protective properties is discovered recently. This phenomenon is taken into account in the model. The models are implemented to newly developed severe accident computer running code。

The preliminary calculations of nuclear pressurized water reactor loss-of-coolant accidents with new types of claddings demonstrate encouraging results for hydrogen generation rate and integral hydrogen production, especially for design-basis accidents. It looks optimistic for considerable upgrade of safety level for future generation NPPs using new fuel and cladding materials.

The best ATF cladding candidates and current ATF experiments throughout the world will be discussed in the presentation.

Keywords: nuclear power plant, perspective accident-tolerant fuel and cladding, cladding corrosion and oxidation, hydrogen release, enhanced level of safety.

Biography:
I was born in 1962. In 1985 I finished Moscow Institute of Physics and Technology. In 1988 I finished post-graduate courses attached to I.V.Kurchatov Atomic Energy Institute, Moscow. I defended my thesis in 1989. Since 1989 I worked at Nuclear Safety Institute, Moscow. Also, I teach students at Moscow Institute of  Physics and Technology. My areas of interest include the safety of nuclear power plants (NPPs) especially NPPs with Russian type water-water energetic reactors (VVERs); analytical and numerical modeling of physical and chemical phenomena during NPPs accidents including fuel cladding oxidation; propagaion of impurities in geological media in the vicinity of radioactive waste burial places; thea safety analysis of thermo-nuclear reactors. I have more than 100 scientific publications.