Comtemporary dry-wet design efforts and economic studies are reviewed and promising configurations are delineated. The basic accounting scheme and all relevant parameters necessary for comprehensive total cost calculations are identified and associated with typical values. Existing thermodynamic and psychrometric models for dry towers, wet towers, turbines, and condensers are then combined with the economic information to derive the total economies of various dry-wet tower configurations. Example comprehensive results for four parallel air-path and one series air-path cooling tower are included. It appears that parallel air-path configurations offer the most economical design for a dry-wet tower; dry-wet cooling towers also appear economically competitive with wet towers in some areas with high water costs.

A realistic determination of the design level of vibratory ground motion for nuclear power plants can be obtained by direct analysis of response spectra of existing accelerograms recorded under conditions representative of the Safe Shutdown Earthquake (SSE). The accelerograms recorded under conditions representative of the SSE are identified on the basis of the geologic and seismologic characteristics of the SSE (magnitude, distance, dimensions of fault break, source mechanism, travel path, and regional and local geology). In order to obtain response spectra at the level representative of the SSE, the representative accelerograms and their response spectra are linearly scaled for magnitude and distance using existing attenuation relations. When the response spectra scaled to a level representative of the SSE have been calculated and plotted, design spectra with the characteristics recommended in U.S. NRC Regulatory Guide 1.60 are conservatively fitted to them.

The successive stages of structural design, and the methods and organization employed at Ontario Hydro in the design of superstructures for thermal power stations are reviewed. The design criteria, some more intricate elements and the ensuing problems are briefly examined. The necessity for accurate estimating and structural design economy is stressed.

Water has become an increasingly critical factor in the siting and development of power generating facilities in the Northeastern United States. A combination of natural events, governmental actions, and public resistance to environmental change has placed serious constraints on the construction of new power plants of all types. This is particularly acute in the Northeast where the highly concentrated population places severe demands on available land and water resources. Recent experience in the Hudson, Delaware, and Susquehanna River Basins provides case histories of this trend. Among possible solutions are offshore plants, inland plants with storage reservoirs, upgrading of conventional hydroelectric capacity, development of pumped storage hydroelectric generation, and construction of energy complexes. Energy complexes that combine in a single site pumped storage hydro, cooling ponds for on-site thermal plants, water supply for downstream thermal plants, and other functions represent an attractive solution.

Failure of shafts driving large axial flow pumps was found to be caused by intake flow pattern. Extensive tests on prototype pump and laboratory model were used to identify and correct the problem. Strains measured on the shaft during pump operation showed the existence of a cyclic bending moment sufficiently large to cause a fatigue failure. The bending moment was not a critical speed phenomenon and was assumed to be caused by hydraulic forces acting on the impeller. Laboratory model tests identified a vortex in the pump intake. The vortex was not centered below the pump impeller and generated an unbalanced force on impeller blades as these passed through the irregular water flow. Changing the shape of the intake eliminated the vortex and large bending moment in the shaft.