Replacing a Fixed Tubesheet Feedwater Heater Design Installed in a Condenser Neck With a U-Tube Design

In 1969 Arkansas Nuclear One Unit 1 (ANO 1), which Entergy Operations Inc. operates in Russellville, Arkansas, installed SWECO-built LP Feedwater Heaters E-5A and E-5B in the condenser neck. The heaters are 1205.4 × 13970 mm (51-inch. ID × 45 ft 10-inch) straight length, fixed-tubesheet design. When the condition of the heaters required replacement, on advice of their Engineering Consultant, ANO 1 decided to replace the fixed tubesheet heater bundle sections with U-tube bundles. The replacements were required to meet upgraded performance requirements and to fit into the existing heater shells with limited changes to length. This paper describes the problems that were encountered and their solutions used to prepare the purchase specification for the replacement bundles and the modifications to the existing heater shells.