Acoustic flow measurement optimizes power output at Rochester Gas and Electric, Ginna plant

In most nuclear plants, including Ginna, the feedwater flow is provided by venturi ΔP flowmeters. Unfortunately, at some nuclear plants it is known that these meters have a tendency to foul, which causes them to indicate a higher flow than actually exists. In the early 1980s, a performance trend analysis by Rochester Gas and Electric (RG ampersand E) indicated a small but significant degradation of power output a few months into each operating cycle following a refueling or maintenance outage. Investigation of plant major components, which included primary and secondary heat balances and main unit testing, led RG ampersand E to suspect that both of the feedwater venturi meters were experiencing fouling, adversely affecting the calorimetric calculations and driving the 100% reactor power level downward. To overcome this problem and recover the lost power resulting from the erroneous venturi flow measurement, a leading edge flowmeter (LEFM) acoustic flow measurement system purchased from Westinghouse Electric Corp. was installed in 1986. Operation of the LEFM system soon confirmed the RG ampersand E suspicions that venturi fouling was the source of the performance degradation at full-power operation