Management Science Applications in the Planning and Design of a Water Supply System for a Nuclear Power Plant

In 1982, the Palo Verde Nuclear Generating Station near Phoenix, Arizona, will begin commercial operation as one of the world's largest power facilities. Locating this multi-unit nuclear power plant in the Arizona Desert was a decision whose uniqueness was exceeded only by the magnitude of the project: Approximately $3.0 billion for three nominal 1300 MWe units needing a total of 90 million gallons of cooling water per day. To supply this resource, Phoenix city wastewater will be conveyed 38 miles to the plant site, treated, stored, used, recycled, and the residues disposed of. Wastewater has been used as cooling water for power plants before, but never in this quantity, in such a climate, and for so critical a use.The overall problem of systems design was a classic unstructured and interconnected situation. Every major decision---on conveyance, treatment plant capacity, method of treatment, size of the storage reservoir, condenser tube material, use of wet/dry cooling towers, cycles of concentrations, and blowdown disposal---was linked in cost and performance with two or three others, and all were surrounded by uncertainties regarding supply, performance, and demand. To comprehensively analyze these factors, a spectrum of Management Science methods was used to develop a project plan, sort through the interconnections, assess their net effects, and select the design parameters of the system.Besides providing direction for the project and comprehensiveness in the final design, the effort was directly responsible for a reduction of $20 million in capital construction costs, or a cash flow savings of $3.5 million per year for the anticipated 30-year economic life of the plant.