The thermal transiert behavior of surface condensers and feedwater heaters was analyzed. Differential equatioms of temperature behavior are defined which permit conveniert simulation by analog computer circuitry with a minimum sacrifice in true representation. Typical constarts for the SM-2 (APPR-1B) condenser were employed to derive a scaled analog circuit. The transient response of this circult to steam flow perturbations is illustrated. The emphasis of these simulations is more on fidelity than on reduction in number of computer components neces. sary. The process of reducing simulation detail is more eastly accomplished in achieving a practical compromise. (auth)