Том 125, № 4 (2019)

Experimental and computational methods of determining the physical power of a critical assembly are proposed. The experimental conditions and results on determining the coefficient of proportionality of the indications of the SCS apparatus and the power of the critical stand are described. The results obtained by different methods are in agreement with one another to within about 20%.

A consistent computational method of modeling complex shockwave processes in two-phase media in the presence of surface-tension forces that makes it possible to model boiling, evaporation, and condensation was developed. The results of modeling cavitation and Soda’s problem with sodium as well as modeling heat and mass transfer in a vertical channel in the presence of sodium boiling under forced lift are presented. Good agreement with experiment is shown.

A mathematical model of corrosion damage to the protective barriers of radiation hazardous marine-based objects, taking account of the stochastic nature of this process, is constructed. The rate of pitting corrosion is determined by many mutually independent factors containing random components. This makes it possible to model pitting corrosion as a random walk process in which the corrosion rate changes discreetly and remains constant for one computational time step. The Monte Carlo method is used to calculate the depressurization time of an object with one protective barrier. The obtained estimates agree with expeditionary observations.

A range of preparatory tasks for decommissioning the U-5 facility at VNIINM was performed in 2010–2016. Comprehensive engineering and radiation inspections were conducted, and cartograms of contamination were constructed. Deposits in the special utility systems were investigated. A detailed investigation of the contamination of the building structures was performed. Radioactively contaminated process media, sources of ionizing radiation, and radioactive wastes from technological equipment and rooms were removed. Design documentation for decommissioning the U-5 facility was developed and a positive final report by a government environmental commission of experts, final sanitary-epidemiological reports, and licensing for decommissioning were obtained. The measures made it possible to increase the radiation safety of the facility and prepare it for decommissioning.

The design of a new fireproof combined filter for purifying a radioactive steam-gas mixture by removing volatile compounds of radioactive iodine during normal operation of NPP as well as during accidental depressurization of fuel rods is described. The filter consists of identical cylindrical sections, each of which possesses a top lid for anchoring spiral filtering elements with variable surface area and a bottom lid with a grid for anchoring sorbents. The first and closing sections along the course of the purified gas flow are filled with sorbent consisting of the inorganic material SiO₂–Cu⁰ or KSKG brand silica gel or a mixture of the two. A granulated sorbent based on SKT-3I brand activated charcoal or Fizkhimin inorganic granulated sorbent based on silica gel is used as a filler in each of the intermediate sections to catch volatile forms of radioactive iodine. The size of the pores in the spiral filtering elements with variable surface area decreases in a direction from the first to the closing section along the course of the purified gas flow; there are at least three sections equipped with sorbent for purifying gases by removing radioactive iodine-containing impurities.

A method of partial modernization of the control systems of special hoisting cranes operating at NPP that is cheaper, in terms of the cost of and time required for complete replacement than the alternative of complete replacement, and meets the regulatory requirements is proposed. The method consists in equipping the cranes with multi-functional autonomous devices, such as operational parameter monitoring systems, anti-collision systems, load control, locking control, and guidance in one or another combination depending on which required functions are not being currently realized. The indicated devices are compatible with one another and can be quite simply built into existing crane control systems irrespective of their type (relay-contactor, frequency-controlled). A description of the devices is given. The proposed autonomous devices (systems) can also be effectively used in designing new cranes.