System design and optimal parameter choice for ships nuclear power plant

Abstract

Research has shown that certain aspects and trends can be formulated for nuclear power plant of various types: 1) power plants may differ in parameters, particularly in mass by factors of 1.5-2.3, dimensions by factors of 1.4-1.9, and thermal efficiency by 30-40%; 2) the dependence of the mass and size on the heat engineering parameters is of turning-point type; 3) the minimum mass and size and the maximum thermal efficiency are provided by substantially different heat-engineering parameters; 4) there is a set of optimal combinations of the heat engineering parameters, which provide close to turning-point values for the mass, size, and thermal efficiency and the dependence of them on the output power; and 5) the optimality criteria for the heat engineering parameters are the relative mass K G (kg/kW), the relative volume K v (m3/kW), and the effective efficiency r/e (%), together with Kop t = K G + b K v + ?(q,)-J; in which b = K#'~ '" and ~ =/~'~,t;'"" are respectively the specific mass (kg/m 3) and the mass per unit thermal reactor power (kg/kW) calculated from the extremal criteria [1]. The power plant has a certain combination of features (Fig. 1) in accordance with what combinations of these parameters are realized. The ship must meet various requirements based on the purpose, including economic, working, ergonomic, and ecological ones. One therefore has to consider whether there is a relationship between the parameters of the power plant and the basic specifications, and if there is, what features should be present in the plant intended for the ship? Experience in designing ship power plants shows that there is a wide variation in the ratio of the total mass of the power plant to the volume of the spaces in which it is located (from 0.69 to i. 16). For nuclear power plants for ships of various functions, that ratio is 1.08-1.16, i.e., almost constant, which suggests that the mass and size of the nuclear power plant have differing effects on the water displacement D w in accordance with the extent of the uniformly distributed load and the material used in the containment. To demonstrate this, one needs to examine a dependence of the form D,,= ]'l<-;+:,p (x). i.(x). ,l(x), I+,. ,.-y. ~,o 1, (2) in which Gpp is the mass of the power plant in t, X the vector for the independent variable parameters of the nuclear power plant, L  d the dimensions of the space for the power plant in m, H the intensity of the uniformly distributed load in MPa, Cry the yield point of the body material in MPa, and "/c the density of the containment material, in tons/m 3. The displacement can be represented as the result of the joint solution of the equations for mass and volume in accordance with the buoyancy laws: in which G i and V i are the masses in t and volumes in m 3 of components of the displacement, including the mass of the nuclear power plant and the volume of the plant rooms, Z~Gsb and AVex being the mass in t of the solid ballast and the excess volume in m 3 intended for providing zero buoyancy,* while 3'sw is the density of sea water.