Excelsior College

Pressurized Water Reactor Steam Generator Material Problems

Solutions to Prevent Capacity Loss and Extend Lifetime

Matthew T. Spire

NUC320 Materials

Professor James Mathus

January 01, 2012

Abstract
Steam generators are a necessary component in PWR. Material issues that affect steam generators reduce the capacity of a nuclear power plant to generate electricity and minimize the lifetime of the steam generator, with both consequences resulting in a loss of profit to the operating utility. Specific problems associated with steam generator materials that are discussed include denting, stress corrosion cracking (SCC), phosphate thinning, as well as vibration and mechanical problems. A connection is established between material issues that affect steam generators and capacity losses as well as decreased lifetime. Finally, solutions are discussed to prevent decreases in capacity and diminished lifetime.

Introduction Steam generators are a critical component of PWR. The function of a steam generator in a PWR is to serve as a heat exchanger between the primary and secondary. The heat exchange that occurs between the primary and secondary creates steam, the steam turns a turbine, the process of which generates electricity. The generation of electricity for profit is the purpose of nuclear power plants, therefore material problems associated with steam generators that reduce the capacity of a nuclear power plant to generate electricity are an important profit consideration. Another significant cost and profit consideration is steam generator replacement cost and replacement power costs during the outage. The solving of steam generator tube-related material problems and the maximization of