Advanced Scale Conditioning Agent (ASCA) Planning, Application Experience, and Results at Seabrook and D.C. Cook Unit 2

Abstract

ASCA technology has been applied more than thirty-five times worldwide since its inception in 2000. This technology has continually grown in popularity since its development as a result of the many process benefits while maintaining minimal outage impacts. Utilities have applied ASCAs for a variety of reasons including: Partial removal of secondary side deposit inventory; Improvement in sludge removal quantity over traditional mechanical cleaning processes; Reduction of tube support plate (TSP) blockage; Improvement in steam generator thermal performance; Partial dissolution and softening of consolidated top of tubesheet (TTS) collars. In addition to several international ASCA applications, two U.S. ASCA applications were performed in 2011 and 2012. In 2011, a TTS ASCA application was performed at Seabrook Station Nuclear Plant. The TTS application was the third ASCA to be executed at the plant; Seabrook performed full bundle ASCAs in 2008 and 2009. In 2012, a full bundle maintenance cleaning ASCA was implemented at D.C. Cook Unit 2. This was the first ASCA application to be executed by the utility. This paper will discuss both the Westinghouse and utility perspective on ASCA application planning, site execution, and process results for TTS and full bundle applications.