Added Capacity from Advanced Condenser Instrumentation and Engineering

Harpster, J.W.
“Added Capacity from Advanced Condenser Instrumentation and Engineering” 4th American Nuclear Society International Topical Meeting on Nuclear Plant Instrumentation, Controls and Humane-Machine Interface Technologies, Columbus, OH, Sept. 2004.


Most Nuclear Power Plants (NPPs) operate at a capacity below their rated or design values by an average value of about 4%. Some of this loss is due to a reduced condenser heat transfer coefficient causing excess back pressure on the turbine. Many of these plants employ nitrogen purging of their condensers to reduce Dissolved Oxygen (DO) in condenser condensate. DO is recognized as a primary cause for corrosion, particularly of iron bearing structural members, including those in the condenser. New condenser diagnostic instrumentation, invented by the author and patented in 1996, provided the data which was used to discern the direct connection between these two observations. The data and correlation led to the development of a comprehensive theory of shell side steam and noncondensables dynamics. The bases for this connection and a summary of the theory in the form of a simple model will be given in this paper. Two examples of known excess back pressure and the use of nitrogen purging in nuclear power plants are discussed, including their impact on performance.

A program for modifying present condensers to improve their apparent heat transfer coefficient and designing new condensers which can operate at their design values is described. Any new condensers designed for the next generation nuclear power plants should consider these designs in order to increase plant efficiency, decrease operational and maintenance cost, reduce DO level and corrosion effects without affecting nuclear power plant safety. The value of data obtained from the condenser diagnostic instrument has made this tool an indispensable aid to management, performance and operations personnel.

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