Deformation control during the welding of AP1000 main pump casing and steam generator

Abstract

The welding of the AP1000 Reactor Coolant Pump (RCP) casing and Steam Generator (SG) is an important issue to maintain the integrity of pressure boundary. The position tolerance of pump casing nozzles after welding will directly affect the internal components of the main pump, as well as the on-site assembling processes. This article investigated the method of controlling deformations during welding (such as assembly alignment, groove design, welding process control, etc), in order to prevent excessive welding deformation and therefore extra discrepancies during pump casing positioning. In this paper, we have developed a welding process, which can allow the installations of AP1000 pump casings to meet all nuclear grade requirements.

Keywords

• AP1000
• Main pump casing
• Welding deformation control