Performance enhancement by an innovative tube cleaning application

Clinton Power Station (CPS) performance had degraded over the past four operation cycles. A large portion of this performance degradation was due to the main condenser not performing as designed. Clinton lake water chemistry has pH of an average above 8.0. This has resulted in an extensive deposition of hard calcium carbonate scale in the 53,160 stainless steel tubes of the main condenser. In the past, attempts were made to clean the condenser tubes with standard mechanical scrapers. These scrapers removed a layer of soft material but did little to remove the hardened deposits. By third refueling outage, the average deposit was 20 mils thick resulting in condenser performance producing a backpressure that was 1.3 inches of mercury (inHg) greater than design. This translated to plant generation losses of $2.6 Million. The majority of these losses occurred during the summer months when CPS has its peak loads. This paper discusses the development of a new product which functions as a scale cutter and tube cleaner; its application on a trial basis and subsequently on a full scale condenser for the first time. It also describes station's experience, plant performance, the improvement, and the cost savings associated with tube cleaning