PGV-1500 steam generator. New problems and solutions

Abstract

The basic questions concerning the development of a steam generator for a nuclear power plant with a VVÉR-1500 reactor are presented. The basic design requirements which follow for steam generators from experience in operating analogs at nuclear power plants and taking account of the requirements for a reactor system are presented. The special features inherent to horizontal-type steam generators, which have been mastered and are used in nuclear power plants in our country, are noted. The domestic and world operating experience is taken into account in the development of the design. It is concluded that the design of the PGV-1500 steam generator satisfies the requirements for the concept of a VVÉR reactor facility for a 1500 MW(e) unit of a nuclear power plant and is competitive on the world market for power-generating equipment for nuclear power plants.An important problem at the present time is to develop high-capacity nuclear power plants which are competitive in the world energy market. The development of a reliable steam generator which operates without failure is one of the main directions in solving this problem.The main requirements which the new steam generator must satisfy are:• the evolutionary principle of development with maximum use of positive experience must be employed in the development work;• the scheme of the steam generator and the design of its elements must provide the required steam productivity and parameters in all operating regimes of the nuclear plant;• all components of the steam generator must operate reliably and safely; • corrosion processes must be eliminated or reduced substantially; • the design must be simple and easy to assemble and operate, the time and dose-usage for service operations and maintenance must be reduced to a minimum;• the dimensions must allow for placement in a protective shell with prescribed dimensions;• the questions of shipment during fabrication and to the assembly site at the nuclear power plant must be solved;• the drawbacks of the steam generators used in nuclear power plants with VVÉR-440 and -1000 reactors must be eliminated or neutralized.The first question to be solved in designing VVÉR-1500 was the choice of steam generator -vertical or horizontal. The vertical generators used in nuclear power plants with PWR, certainly, have their own advantages and disadvantages [1]. Without making a detailed comparison of the two types of steam generators, we recall the main advantages of the horizontal generators:• the moderate steam load on the evaporation surface (0.2-0.3 m/sec) permits the use of a simple separation scheme with reliable supply of the required moisture in the steam;

Steam generators – horizontal or vertical (which type should be used in nuclear power plants with VVER?)

“…On the basis of operating experience gained over many years, horizontal steam generators have advantages over vertical steam generators, the main ones being [7,8]:…”

“…Horizontal PGV-1600 [7] Vertical EPR [15] Nominal The characteristic features of vertical steam generators are relatively long heat-exchange tubes (>20 m) as compared with the horizontal generators (average length 11.5-12.4 m) and thinner walls. This increases the thermal efficiency somewhat but decreases the longevity of the steam generator.…”

“…They appear in certain implementations of vertical steam generators and in the PGV-1600 design [7]. They appear in certain implementations of vertical steam generators and in the PGV-1600 design [7].…”