The paper describes experimental works, based on liquid-scintillation method of determining ¹⁴С concentration. Methodological approaches were developed for radiocarbon analysis using Pyrolyser-6 Trio system for samples ignition and ashing. Accuracy of researches performed was assessed by means of analysis of certified radiocarbon standards. As the result of experimental activities, for the first time the quantitative data was obtained for ¹⁴С concentration in soil of the «Experimental Field» testing site of Semipalatinsk Test Site. Radiocarbon was found to have a non-uniform character of distribution at the territory researched. The highest concentration of the radionuclide was registered directly in the epicenters of surface nuclear tests.

The paper presents the results of spectroscopic measurements of plasma discharges at the KTM tokamak. The measurements were carried out during the June 2021 campaign, which plasma discharges were obtained with a plasma current from 120 kA to 150 kA and a duration of ~250 ms.
In connection with the design changes inside the vacuum chamber of the tokamak, special attention is paid to the study of the elemental composition of the plasma and the analysis of impurities and the ways of their entry is carried out. Impurities in plasma directly affect radiation losses. Optical spectroscopy (OS) is one of the main methods for studying the penetration of impurities into plasma.
An Avaspec-ULS2048CL-EVO-RS-BB spectrometer was used to determine the emission spectrum of the KTM tokamak plasma. The time evolution of the hydrogen lines was measured using the diagnostics of a Hα-Dα monitor equipped with narrow-band interference filters (FWHM 1 nm).
Based on the measured emission spectrum, it was found that in the hydrogen plasma of the KTM tokamak, in addition to the presence of a working gas, there were also impurities of carbon, oxygen, nitrogen and argon (C, O, N, Ar) in various ionization states.

In the coming decades, it is possible to start exporting fast reactors with a closed nuclear fuel cycle to non-nuclear-weapon countries, which will require strengthening the nuclear non-proliferation regime and increasing the effectiveness of IAEA safeguards. This can be achieved both by creating technical barriers and by improving the system of accounting and control of nuclear materials and ensuring their reliable physical protection. Using the example of the BREST-OD-300 reactor under construction as part of a pilot demonstration power complex, the analysis of design and technological features that prevent or seriously hinder the switching of nuclear materials or the use of technologies by the importing State in violation of its international obligations to produce nuclear weapons or other nuclear explosive devices has been carried out.

The paper presents the results of testing the tendency to intergranular corrosion of welded joints of dissimilar steels 12Kh18N10T and AISI 316 without heat treatment, as well as after quenching and stabilizing annealing. By welding control samples, optimal parameters of argon-arc welding were determined for pipes with a diameter of 42 mm and a wall thickness of 3.5 mm. A filler wire was selected according to Scheffler diagram.

Based upon present ideas of physical-chemical properties of polonium and its up-to-date determination techniques, a technique of ²¹⁰Po radiochemical determination in urine samples was developed followed by alpha-spectrometry. The technique was tested on 24-hour urine samples collected from the personnel of the branch “Institute of Radiation Safety and Ecology” RSE NNC RK. The range of ²¹⁰Po absolute activity per a 24-hour urine sample was determined to be 1.8·10^-3÷0.12 Bq. ²¹⁰Po contribution to the total dose of personnel internal exposure was estimated to be equal to 0.3 mSv/year.

In this work, to assess the radiation damage of beryllium under low-temperature neutron irradiation, samples from beryllium grade TShG-200 with an oxide phase concentration of about 1 wt % were studied, which were kept in the IVG.1M research reactor for a long time and were irradiated to fluences 0.8–4·10²⁰ neut./cm². Also, unirradiated original witness samples of the same brand were tested to compare the results.
The aim was to establish the level of radiation degradation of beryllium samples during their tests in the IVG.1M reactor. Mechanical tests for three-point bending and tension were performed to determine the strength of beryllium samples, and their microhardness was also measured. To determine the degree of swelling of the beryllium samples their densities were measured by the method of hydrostatic weighing in the medium of distilled water.
According to the results of short-term bending and tensile tests, it was found that the beryllium material after reactor irradiation softens in the range of 9.3–16.7%. And the results of measuring the microhardness showed an increase of up to 23%. Density results did not reveal swelling of the samples after low-temperature neutron irradiation.
After mechanical tests, special studies of fractures and microstructural analysis were carried out, which did not reveal noticeable changes in the microstructure of beryllium after irradiation.

Within the framework of Semipalatinsk Test Site (STS) scientific and technical potential development, the general review of publications on the STS issues state assessment in terms of its territories economic use was made.
Targeted systematization of information collected for a multi-year period can be the basis to create a problem oriented research database of STS.
The creation of a general concept for the test site area returning into economic turnover based on building of the “Problem Tree” will allow to determine the criteria of data systematization, and create thematic, well-structured archives of information for subsequent managerial decision making on the further test site lands use.

The paper considers a scheme for increasing the efficiency of generating electricity at nuclear power plants based on the implementation of binary cycles. The energy and exergy analysis of the effectiveness of such cycles has been carried out. The main performance indicators are obtained. On the basis of exergy analysis the main sources of losses at nuclear power plants operating on a binary cycle have been obtained.