QUANTITATIVE-EVALUATION OF SWELLING OR SHRINKING LEVEL CONTRIBUTIONS IN STEAM-GENERATORS USING SPECTRUM ANALYSIS

The swell and shrink phenomena make controlling the water level in ste am generators extremely difficult, along with the flow errors. Therefo re, quantitative evaluation of the swell and shrink is interesting and valuable in analyzing the nuclear steam generator and in the design o f its controller. The power spectral density function (PSDF) distribut es the power of the signal for frequencies. This excitatory input sign al is assumed to be the band-pass white noise, which is more realistic than the ideal white noise. The integration of the PSDF over frequenc y is defined as energy. We derive the energy contribution of each dyna mic mode using the PSDF. Its energy contribution can be calculated eas ily by arithmetic calculation.