[en] The first author’s name should read A. K. Valter.

[en] The radionuclide ⁹⁹Mo was produced and separated in the process of irradiating powdered mixtures of molybdenum compounds and buffer particles by 30 MeV protons. The separation is based on the Szilard–Chalmers effect wherein ⁹⁹Mo recoil particles are fixed in inert buffer particles. Two types of targets were investigated by using mixtures: soluble molybdenum compound–insoluble buffer and insoluble molybdenum compound–soluble buffer. ⁹⁹Mo yield equal to 20% with enrichment coefficient 18.3 was obtained by using a target consisting of a mixture of submicron ¹⁰⁰MoO₃ and Al₂O₃ particles; the ⁹⁹Mo yield was equal to 20% and the enrichment coefficient 18.3. For a target with the composition ¹⁰⁰MoS₂ + KCl, making it possible to separate ⁹⁹Mo recoil atoms directly into solution, the ⁹⁹Mo yield was equal to 8.7% and the enrichment coefficient 30.7.

[en] The maximum graphite temperature upon increasing the reactor power in the No. 1 unit of the Leningradskaya NPP to 80% of the nominal value in November–December 2013 after the restoration of the service life characteristics of the graphite stack is presented. A comparative analysis is made of the temperature regime of the graphite stack at power equal to 80 and 100% of nominal value before and after restoration of the service life characteristics at nominal helium content in the gas mixture blown through the reactor space. A comparison is made of the maximum temperature of the graphite stack of the reactors in the No. 1 unit of the Leningradskaya NPP and No. 2 unit of the Kursk NPP upon startup and assimilation of the power after restoration of the service life characteristics. The effect of the restoration of the service life characteristics on the thermohydraulic regime of the fuel channels in the reactor is studied.

[en] Research building B at the Bochvar High-Technology Research Institute for Inorganic Materials (VNIINM) located within the city limits of a dense residential development was decommissioned in 2013–2015. Radioactively contaminated equipment and utility services were disassembled and removed, building structures were decontaminated, the framework was dismantled, the grounds of the development site were restored, and radioactive waste was transferred to specialized organizations. The framework was liquidated in strict accord with the norms and regulations governing the use of atomic energy.

[en] An approach to the comparative assessment of the impact of accidental radioactive emissions on the biota and radioecological validation of nuclear fuel cycle objects is presented. It is shown that the dose loads on woody tier in a coniferous forest as a result of severe accidents in NPPs with PWR-890, BWR-1412, and EPR-1600 significantly exceed the limit recommended by the ICRP. The impact of the radiation factor can result in serious disturbances in forest ecosystems in the immediate vicinity of NPPs.

[en] The main results of tests performed on VVER-1000 fuel elements with high burnup of fuel in a channel of the MIR channel reactor for LOC accident conditions are examined. The experimental setup contains one fuel element, which is arranged along the central axis. The aim of the tests is to determine the parameters of cladding depressurization. In the experiment, questions concerning fragmentation, axial displacement, and possible escape of fuel to outside the cladding were studied and the properties of the cladding material and fuel, which were subjected to the extreme parameters, were determined. The main parameters and the results of two experiments are presented. The conditions under which fuel-element depressurization occurred are determined.

[en] A linear-algebraic form of the equations of the method of characteristics, which is used to approximate the neutron transport equation, is obtained. It is shown on the basis of the obtained linear-algebraic form that the discrete form of the conjugate equation differs from the algebraically discrete problem constructed by linear-algebraic transformations of the discrete form of the normal problem. The reason for the discrepancy lies in the approximation of the volumes of the spatial cells in covering the working region by a network of characteristics. It is shown by means of test calculations that when the network of characteristics is refined the solution of the conjugate transport equation converges to the solution of the algebraically conjugate problem.

[en] An economics-mathematical model for performing analytical calculations of the present value of separative work for uranium isotopes in a separation plant currently being designed using gas centrifuge technology is examined. Analytical expressions are obtained for the present value of the separative work, the internal rate of return, and the payback period of the separation plant as a function of its main engineering and economics parameters – productivity (capacity), capital investment, and operating expenses. Calculations of these criteria for investment efficiency are presented for a wide range of initial data. It is shown that the calculation of the present value of separative work must be performed in a complex with other investment efficiency criteria in order to determine their optimal combination.

[en] A problem in operating NPP with VVER is that waste solutions containing ethanolamine and ammonia from regeneration of ion-exchange filters from the second loop must be processed. The amount of ammonia in the regeneration solutions is equal to 85% of the total amount of the contaminating substances. The water chemistry regime of the second loop without ammonia or with ammonia replaced by dimethylamine is examined. It is shown that the use of dimethylamine makes it possible to increase the duration of the filtration cycle for ion-exchange filters of the purification systems, decrease the concentration of products of corrosion, reduce the environmental impact, and simplify the waste water purification technology.

[en] To ensure that technological installations using radionuclide sources of radiation operate at top efficiency, the effect of the irradiation system parameters on the radiation utilization factor was studied. It was found that the radiation utilization factor depends not on individual parameters of the irradiation system but rather on a certain combination of these parameters. A dimensionless criterion was determined on the basis of these investigations – a complex based on a set of parameters of installations with maximum radiation utilization factor. The radiation utilization factor was determined as a function of the irradiator–irradiated object distance. The numerical range of the criterion corresponding to the maximum radiation utilization factor is shown. Data by means of Monte Carlo calculations were selected by performing experimental studies using independent dosimetric systems.