Optimization of Heater Design Conditions in Power Plant Cycles

Abstract

This paper presents a method of tailoring the regenerative feedwater-heating system in a nuclear plant to the availability of extraction openings on the main turbine. This is accomplished by optimizing the heater design conditions of each individual heater, in conformance with the peculiarities of the particular cycle being used, and the evaluation parameters that are applicable. It is shown by example that for a typical six-heater, reheat nuclear plant the evaluation is improved. The results show that such “total optimization” in an 880 Mwe plant will accomplish: 1 - An improvement of 27 Btu/kwhr in heat rate, 2 - An increase of 2500 kw in net output (at constant reactor thermal power), 3 - An increase of about 18.5 percent in heater surface, in the reference cycle, for the selected values of the heat rate and incremental kw evaluation parameters, and heater surface cost of $10/sq ft. However, if an incremental heater cost is used, say $6/sq ft, optimum evaluation yields: 1 - An improvement of 45.3 Btu/kwhr in heat rate, 2 - An increase of 4200 kw in net output (at constant reactor thermal power), 3 - An increase of about 42 percent in heater surface. For this set of conditions, there is an improvement in evaluation of about $300,000 for the 880 Mwe plant.