Том 122, № 4 (2017)

A comparative analysis is made of calculations of a loss-of-coolant accident in a 1500 MW(t) fast reactor. The COREMELT code with different neutron-physical modules RADAR3D and RAKAR2D and the same thermohydraulic module COREMELT are used. The computational results are used as a basis for comparing the self-protection of a reactor with a sodium cavity at the top of the core for the case of a serious accident with coolant boiling. The effect of the diffusion and transport modules of the spatial neutron-physics models on the calculation is analyzed.

The power coefficient of reactivity of VVR-Ts was previously determined only in the range 10–11 MW. The aim of the present work was to determine the power coefficient of reactivity in the range 1–10 MW. The experiment was performed on a completely depoisoned reactor. The change in the reactivity excess was determined according to the position of the control rods. It was shown experimentally that the power coefficient of reactivity is not constant and is negative for the given power range. Thus, the VVR-Ts reactor can operate safely in different operating regimes.

A magnetic flowmeter for liquid sodium is described. The inductor in this device consists of an electromagnet generating a pulsed, low-frequency, magnetic field. The use of a pulsed magnetic field made it possible to separate the informative component of the signal from all electromagnetic interference whose time variation is not a multiple of the frequency of the excitation magnetic field. Thus, all interferences at the industrial frequency and the thermo-emf are eliminated. This increases the accuracy of flow rate measurements significantly and makes it possible to reduce the magnetic field in the channel. The power of the inductor does not exceed 0.5 W. There is no need to adjust the zero point, and it is possible to measure low flow rates and the reverse flow. The physical principles of the method of measurement, the design particulars and technical characteristics of the device, and the results of tests are examined.

Experts at the National Research Center – Kurchatov Institute have proposed compact reprocessing of spent nuclear fuel from the naval fleet as well as NPPs close to the Arctic coast, directly at the site of offloading, on the basis of an innovative, experimentally verified, fluoride-distillation technology. They propose developing a mobile system consisting of a seagoing carrier (vessel with small displacement) or terrestrial carrier (railroad platform) on which is mounted a compact process line consisting of fluorination and purification apparatus as well as auxiliary setups. There are no liquid wastes in the fluoride processes; solid wastes are to be removed, as they are formed, from the mobile system into special sites in waste locations of the Arctic coast for long-term dry storage in concrete containers.

The increase in the efficacy of studying well saturation in simultaneous analysis of radiation fields by means of pulsed neutron, activation, and spectrometric logging is examined. It is shown that neutron activation logging can in principle be realized in experimental testing of an operating model of apparatus in producing geophysical objects. Technical solutions using neutron well radiators based on sealed accelerator tubes with a laser source of deuterons and magnetic insulation, as a result of a large neutron yield combined with high pulse stability, as well as a thermally stabilized γ spectrometer, are proposed and validated.