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Vol 127, No 2 (2019)
- Year: 2019
- Articles: 11
- URL: https://journal-vniispk.ru/1063-4258/issue/view/15568
Article
Neutronics Model of the IVG.1M Reactor: Development and Critical-State Verification
Abstract
The results of the verification of a model of the IVG.1M reactor based on experiments performed in 1990 and 2017 are reported. Startups of the reactor which are associated with its emergence into a critical state and measured values of the power, neutron flux density, and efficiency of the CPS [control and protection system] components were chosen for verification The isotopic composition of the fuel and the beryllium blocks formed by the time the first water-cooled process channels with high-enrichment fuel were extracted from the reactor (2017), was calculated. It was established on the basis of the verification results that the measured parameters agree well with the calculations. Currently, the model of the IVG.1M reactor is used for evaluating the post-conversion characteristics of the reactor as well as the parameters of planned experiments.
69-76
Features of Mass Transfer of Noncondensable Gases by Primary Coolant of Nuclear Icebreaker Reactors
Abstract
To study the characteristics of the mass transfer of noncondensable gases in the primary loop of the nuclear icebreaker reactors, models of the core and the up-core space were developed using the Relap5 (USA) and Fluent (USA) codes and modeling of interphase mass transfer and transport of the gas phase by the water coolant was performed on these sections. Spatial non-uniformity of the content of undissolved gases, which arises as a result of vapor-gas bubbles concentrating in the vortex structures of the flow and resulting in a significant reduction of their dissolution rate, was revealed. This must be taken into account in the analysis of the operation of the primary loop equipment of nuclear icebreakers (hydrogen absorption in the titanium alloys of steam-generator piping, nodular corrosion of the zirconium cladding of the fuel rods).
77-82
Industrial Trials of a Modernized Separation Part of Moisture Separators-Reheaters at the Leningrad and Smolensk NPP
Abstract
The purpose of this work is to compare industrial trials of modernized intermediate SPP-500-1 moisture separators-heaters of the K-500-65/3000 turbines in the No. 4 unit of the Leningrad NPP and the No. 1 unit of the Smolensk NPP. It was found that the distribution of the separated moisture along the perimeter and height of the steam space at the egress from the separation units is uniform in both NPP. A very small increase of the moisture concentration at the wall was obtained in individual apparatus at the Smolensk (No. 24) and Leningrad (No. 72) NPP. The flow rate of the separated material and the condensate of the warming steam, as measured on the Nos. 1 and 2 turbines of the Smolensk NPP, is close to that obtained on the Nos. 7 and 8 turbines of the Leningrad NPP. In the course of the industrial trials, it was shown experimentally that the moisture and flow rate are the same. This confirms the reliability of the results, which after modernization are close to the design-basis level.
83-86
Improvement in the Technology for Extracting U–9%Mo Granules from Aluminum and Aluminum Alloy Based Dispersion Compositions
Abstract
A classification by form and fraction of production turnovers with U–9%Mo fuel is made. The technology developed at the Institute of Physics and Power Engineering allowing unconditioned fuel rods and recovered material to be dissolved in a 10% solution of sodium hydroxide at temperatures 75–100°C is examined. The process developed for the Novosibirsk Chemical Concentrates Plant for extracting U–9%Mo granules from recovered material obtained in the production of dispersion-type fuel rods of the experimental IRT-3M fuel assemblies is examined. The optimal regimes for extracting U–9%Mo granules during the processing of recovered material obtained in production of dispersion fuel rods are determined and perfected. The basic chemical reactions involved in the process of dissolution of the aluminum matrix are presented. The U–9%Mo granules, initial and recovered from the dispersion fuel composition of the kernels and fuel rods, were investigated, the possible differences between them were determined, and the possibility of using recovered granules in the production of dispersion fuel rods was evaluated.
87-92
Radwaste Volume from VVER-1000 Spent Fuel Reprocessing and Fractionation Variants
Abstract
The possibilities of minimizing the volume of waste are examined for the reprocessing of spent nuclear fuel from VVER-1000 and the matrix material for high-level wastes. The analysis takes into account the designbasis isotopic composition of VVER-1000 spent fuel and the current normative base in the sphere of waste management. It is shown that deep underground disposal of radioactive wastes cannot be avoided at the present stage of development of the reprocessing technologies for the spent fuel from thermal reactors and with the existing legislation associated with the conditions of use of matrices for solidification of wastes and the conditions of waste disposal. Variant methods for decreasing the volume of underground disposal of radwaste are proposed.
93-98
Modular Testing of Dinitrogen Oxide (Nitrogen Hemioxide) Catalytic Decomposition Technology for Off-Gas Cleanup Systems for Brest Spent Nuclear Nitride Fuel Reprocessing
Abstract
Dinitrogen oxide N2O (nitrogen hemioxide) is one of the harmful components of the off-gases during the reprocessing of spent nitride fuel. It enters the gas phase during the dissolution of nitride fuel in nitric acid and denitration of high-activity raffinate or the bottom solution from the evaporation of intermediate-level wastes. The preferred method of neutralizing it is high-temperature catalytic decomposition. Compositions based on γ-aluminum oxide coated with catalysts were found previously. One of the compositions was checked on a semi-industrial setup. The efficiency of N2O decomposition was studied as a function of temperature. It was established that almost complete decomposition occurs at 465–480°C. The specific rate of N2O decomposition at 425–480°C was found as a function of the initial concentration. It is shown that for constant initial concentration of N2O the specific decomposition rate is almost the same in the investigated temperature interval.
99-104
Variant of Off-Gas Cleanup in Liquid Radwaste Vitrification
Abstract
A variant of a gas cleanup system for the vitrification of liquid radwaste is proposed. The characteristics of the gas flow formed upon inclusion of liquid high-level waste in borosilicate glass are examined. Two approaches to a gas cleanup system for radwaste vitrification are analyzed. A validated choice of gas cleanup equipment is made. The proposed gas cleanup system provides an efficient and compact way of cleaning up off-gases from the vitrification of high-level wastes formed, upon regeneration of spent nuclear fuel, from aerosols, volatile compounds of cesium, ruthenium, and iodine, and nitric oxide.
105-108
Kinetics of Radiation-Induced Optical Absorption Spectra in LPX-100, -200 Protective Glasses
Abstract
The results of studies of the kinetics of radiation-induced optical absorption spectra of commercially produced glasses LPX-100 and -200 (Lemer Pax Co., France) after γ-irradiation to 1 MGy in the wavelength range 320–1000 nm are reported. The restoration of light transmission was monitored for 120 days. The linear coefficients of attenuation of γ-radiation by glasses were measured using a KRONA-II-04 γ-spectrometer with OSGI standard radiation sources 60Co (1.173 and 1.333 MeV) and 137Cs (0.661 MeV). The experimental data make it possible to determine with adequate accuracy the applicability of the studied glasses under other conditions of irradiation. A brief comparative analysis of the results obtained for TK100 and TF103 glasses by other authors is given.
109-114
Radiation Diagnostics of Pipelines and Equipment of Oil and Gas Production Complexes
Abstract
An alert indicating the formation of salt deposits in the pipelines of oil and gas production complexes reduces the financial losses associated with the removal of these deposits and the loss of production. A method of taking into account the presence of the native radionuclide 232Th and its decay product 208Tl in the deposits is proposed for performing radiation diagnostics of pipelines. The appearance of the deposits is identified according to the 2.614 MeV γ-rays. The thickness of the deposits is determined according to the attenuation of the γ-rays from an external thorium dioxide source placed on the outer surface of a pipe. Calculations confirmed the presence of 1–2 mm thick deposits with probability 0.9 and a false positive rate of 0.01 in 1 h measurements with background 3 counts/sec. A 232Th-based external source with activity 105 and 106 Bq makes it possible to determine deposit thicknesses 2.5–3 and 1–2 mm, respectively, with measurement time 1 h and error about 15%.
115-119
Conditions and Initial Data for Reconstructing the Environmental Radioactive Contamination and Population Dose Loads Resulting from a Nuclear Accident on a Nuclear Submarine in Bukhta Chazhma
Abstract
Refined initial data are presented for retrospective prediction and analysis of the radiation conditions in Primorskii Krai after a nuclear accident on a nuclear submarine on August 10, 1985 in Bukhta Chazhma. The initial and boundary conditions are substantiated, including sources of radioactive contamination of the environment, emission intensity of the determining dose-generating radionuclides, weather conditions, and particulars of the transport of the radioactive cloud above the ship repair yard, Dunai Peninsula, Zemlya Petra Velikogo, and Primorskii Krai territory. Substantiation is given for choosing the systems PARRAD and ROUZ for reconstruction of past events to predict the transport and spreading of radioactive substances in the atmosphere, making it possible to evaluate the radiation consequences of the accident for the population of Primor’ya and the adjoining part of China, including environmental contamination, taking into account actual data, numerical estimates, and reconstructed weather conditions for the period of the accident and on the days preceding and following it.
120-126
Scientific and Technical Communications
Theoretical Basis for Using Hydrogen Reduction in Titanium Production
Abstract
It is proposed that the cost of production of titanium sponge can be lowered by replacing the expensive and environmentally hazardous Mg-thermal conversion process by hydrogen reduction of titanium tetrachloride. The Kroll process, which is mainly used to produce titanium, is costly, which determines the high cost of titanium sponge. The reprocessing of titanium sponge into ingots requires large amounts of energy and specialized equipment. Preliminary research shows that hydrogen reduction of titanium with significant production cost reduction and enhanced environmental compatibility of the process is theoretically possible.
127-129