Sequoyah Nuclear Plant Unit 2 Steam Generator Replacements. Hamilton County, Tennessee

摘要

The Tennessee Valley Authority (TVA) proposes to replace the four steam generators in Unit 2 at the Sequoyah Nuclear Plant (SQN) during an outage scheduled for October 2012. Steam generators, a type of heat exchanger, are large cylindrical pieces of equipment used to produce steam for propelling the turbines, which then spin the generators to produce electric power. SQN is located approximately 18 miles northeast of downtown Chattanooga, Tennessee. The subject steam generators are about 68 feet long and 15 feet in diameter. When they are in operation, they stand upright and are located in the concrete containment building. The steam generators use the extremely hot pressurized water from the nuclear reactor to produce a continuous supply of steam. This is accomplished by circulating the hot water from the reactor through a large number of tubes. Incoming 'cool' water (i.e., condensate) is circulated around these tubes, and heat is transferred to the incoming water, producing steam. The steam produced is then collected at the top of the steam generator and directed to the turbines. The decision before TVA is whether to continue to operate Unit 2 at SQN without replacing the four steam generators or to replace the four steam generators in Unit 2. Replacement of the steam generators would involve purchasing the generators, transporting them to the site, removing the old steam generators, installing the generators, and on-site storage of the old steam generators.