Intake and recycle modification model study Prarie Island nuclear generating plant

The thermal-hydraulic model study reported herein was conducted to study why a nonuniform temperature distribution in front of the screenhouse of the Prairie Island Nuclear Generating Plant occurs when warm water is recycled, and how the temperature distribution could be made uniform. The study was conducted for Northern States Power Company (NSP) in cooperation with Stone and Webster, Inc., Denver, Colorado. When the original skimmer wall cooling water intake for the Prairie Island Plant was studied in a physical' model at the St. Anthony Falls Hydraulic Laboratory in 1971, it was already observed, that recycled warm water and incoming cold water would not fully mix. (See External Memorandum No. M-128, "Model Studies on Cooling Water Intake Channel of Prairie Island Nuclear Generating Plant," 1971.)NORTHERN STATES POWER COMPANY Plant Engineering and Construction Department Minneapolis, Minnesota STONE & WEBSTER ENGINEERING COMPANY Denver, Colorad