Vol 119, No 5 (2016)

The primary stages in the develop of disperse fuel elements for the cores of propulsion reactors, floating power-generating units, and small- and medium-size nuclear power plants are analyzed. The experience gained in developing fuel elements for the reactor cores of nuclear ships and the evolution of cladding materials (corrosion-resistance steel, zirconium alloys, and chromium-nickel alloy), fuel, and fuel-element design are analyzed. It is shown that the designs and technologies guaranteeing the reliability and life characteristics of fuel elements in the reactor cores on nuclear ice breakers have now been developed. The use of the new materials opens up paths for significantly increasing the performance and service life of reactor cores as well as decreasing nuclear fuel enrichment while preserving the primary decisions made in the designs and fabrication technologies.

The different stages in the development of fuel for research reactors are analyzed. Validation is given for high-density fuel based on the alloy U–9Mo for the fuel elements of swimming-pool type research reactors. Two effective methods of increasing the radiation resistance of the fuel composition, comprised of high-density uranium-molybdenum fuel in an aluminum matrix, have been developed and experimentally corroborated. Reactor and post-reactor studies of mini fuel elements and full-size fuel assemblies with uranium-molybdenum fuel have been completed and show this fuel to be serviceable.

The main applications and trends in the development of modern high-current superconductors, the characteristics of niobium-titanium superconductors for the FAIR (Germany) and NICA (Dubna, Russia) accelerator complexes, medical tomographs, and Nb₃Sn superconductors for high-resolution spectrometers and modernization of the large hadron collider are examined. Advanced composite superconductors developed at VNIINM for different applications are described. The main results of development work on technologies for the fabrication of targets for spraying buffer and superconducting layers and for substrate tapes of different types for the fabrication of second-generation high-temperature superconductors are examined.

The basic aspects of designing VVER fuel elements are examined: directions for improving fuel-element design determined by current trends in nuclear power; directions for the development of a methodology for the computational validation of the behavior of fuel elements in design basis regimes of normal operation, disruptions of normal operation and in design basis accidents; and questions concerning the experimental validation of design criteria.

Crystallization refining is a technological operation that can separate and purity desired products (fissile materials) during the reprocessing of spent nuclear fuel. A mathematic model presented in this article describes the stationary operating regime of a linear crystallizer and makes it possible to determine the parameters of the process that ensure the most efficient separation of the desired products.

Methods for depositing functional and protective coatings on articles used in the nuclear engineering and for general industrial purposes that have been developed at VNIINM are described. The methods and their advantages are examined and applications are substantiated. Examples of the adoption of the technologies described are presented.

The strategy for the growth of nuclear power in our country in the first half of the 21st century provides for building and commissioning new-generation fast reactors with different coolants: sodium (BN-800, BN-1200, MBIR) and lead (BREST-OD-300). Structural materials with the required level of radiation and heat resistance as well as corrosion resistance upon exposure to the fission products of nuclear fuel, in the coolant, and the spent-fuel pool must be developed for the reactor cores in order to ensure the performance of the reactors under construction and to reach economically expedient burnup of nuclear fuel. The basic results of the performance validation of structural materials in application to their use in the cores of operating (BOR-60, BN-600) and advanced fast reactors with different types of coolants as well as the prospects for further advancement of the research are presented.