Improvement of the equipment in fast-neutron reactor facilities

Abstract

Information is presented on the development of the main equipment of the BN-1200 advanced reactor facility: first-and second-loop main circulation pumps, intermediate heat exchanger, actuation mechanism of the cold filter-trap control and protection system, autonomous and air heat exchangers, steam generator. The approach to the development of the equipment is based on maximum use of the experience gained in operating BN-350 and -600 as well as experience in developing the BN-800 design, which gives a basis for ensuring reliable operation of the BN-1200 equipment. New solutions for improving the technical-economic indicators and increasing the safety of a power-generating unit, whose validation required R&D work, are examined at the same time.The operation of BN-350 and -600 as well as the development of the BN-800 design made it possible to accumulate a great deal of experience in developing and operating the entire system of equipment used in fast-neutron nuclear facilities [1][2][3]. For this reason, the possible technical solutions directed toward improving the equipment in order to improve safety and the technical-economic indicators of the next-generation facility BN-1200 are chosen on the basis of an analysis of the experience gained in developing and operating fast-neutron reactors taking account of the required R&D work.First-and Second-Loop Main Circulation Pumps. The designs of MCP-1 and -2 for BN-800, -1200 are based on solutions checked in the course of operation over a long period of time as part of BN-600. Structurally, MCP-1 in BN-1200 is an immersible centrifugal vertical one-step pump with bilateral intake with a bottom hydrostatic bearing (Fig. 1a).In developing MCP-1 for BN-1200 higher, as compared with MCP in BN-600 and -800, service life indicators and mass/size characteristics must be attained. Many years of operation made it possible to determine the factors that limit the service life. The main factor is cavitation-erosion wear of the blades in the working wheels. To develop MCP-1 for BN-1200, satisfying the requirements, different structural variants with different rotation rate of the rotor and different structural implementation of the working wheels and guiding apparatus are being developed. This work will increase the service life of the working wheels from 4.5 (MCP-1 BN-800) to 16 years.The design of MCP-2 BN-1200 is based on the solutions checked over long-term operation of MCP-2 BN-600. The operationally confirmed service life characteristics of MCP-2 BN-600 are close the values required for MCP-2 in BN-1200 -14.4 and 16 years, respectively.