Vol 125, No 6 (2019)

The design of the BN-1200 sodium-cooled fast reactor is analyzed from the standpoint of its compliance with the criteria fitting the promising Gen-IV reactor facilities. The basic technical solutions adopted in the BN-1200 design making it possible to meet the requirements of consistent development of non-proliferation and safety, cost-effectiveness, and physical protection are described. The BN-1200 concept is evaluated on the basis of 26 criteria developed as part of the Generation IV international forum for the Gen-IV sodium-cooled fast reactor. The compliance of the safety requirements used in the development of the BN-1200 design with the design criteria for the Gen-IV sodium-cooled fast reactor developed as part of the Generation IV international forum is analyzed.

A small ground-based nuclear power plant with two RITM-200 reactors is examined. The plant is intended for electric and thermal energy production and desalination of water. The general layout of the site, arrangement of the basic engineering and technical structures, characteristics of the reactor and steam turbine plants, and systems and equipment of the power plant are examined. RITM-200 is used in the universal nuclear icebreakers now under construction. Its compactness and capacity for operating in a maneuvering regime, flexibly following the required power, makes it possible to attain high technical and economic performance and plant efficiency. The design of a power plant with RITM-200 complies with the current global requirements and trends in the field of safety of nuclear power plants. The requisite number of active and passive safety systems are provided for this purpose. Optimization R&D to improve the technical and economic characteristics of the plant and increase its commercial attractiveness is to be performed at later stages of the design process.

A computational study of ¹⁷⁷Lu production in the neutron spectra of 26 nuclear research reactors was performed by two methods: from ¹⁷⁶Lu and ¹⁷⁶Yb. It is shown that the production of ¹⁷⁷Lu from ¹⁷⁶Lu with satisfactory specific activity ~7.4·10⁵ GBq/g and higher can be accomplished only in reactors with thermal neutron flux density not less than 10¹⁴ sec^–1·cm^–2. Under long-duration irradiation, not only is the specific activity of the desired isotope reduced but the contribution of ^177mLu in the activity increases, as a result of which the quality of the final product is lowered. The accumulation of ¹⁷⁷Lu from ¹⁷⁶Yb makes it possible to obtain high specific activity in all research reactors and requires using targets with high enrichment with ¹⁷⁶Yb and minimum content of ¹⁷⁴Yb. In addition, most importantly, the specific activity decreases under irradiation in reactors with high thermal neutron flux density, first and foremost, in SM and HFIR research reactors.

Possible scenarios of nuclear and radiation accidents with the appearance of a hypothetical uncontrollable self-maintaining chain reaction accompanied by emission of radioactive substances into the seawater as well as with the escape of radioactive substances as a result of the corrosion of the reactors are examined. A propagation forecast is made for ¹³⁷Cs entering the Barents and Kara Seas as a result of accidents occurring at the locations of objects, containing spent nuclear fuel, at the sea bottom and upon being lifted from the bottom and transported to a salvaging facility. The possible scales of radioactive contamination of seawater and bottom deposits, including restricted fishing areas, are determined. The predicted consequences are compared with the admissible norms and the results of discharging of liquid radwaste into the Irish Sea from radiochemical plants in Sellafield (Great Britain).