Identification and Resolution of Piping Analysis Activities for Extended Power Uprates at Nuclear Plants

Recent experience has shown that many utilities have installed new feedwater flow measurement instrumentation, which is designed with new, proven technology that more accurately monitors feedwater flow and therefore, allows for improved thermal power level calculations. As a result of this new approach, many utilities have been able to extend limited power upgrades to the tune of 1.4%, and yet with no noticeable additional environmental impact. These electric power increases are generally attributable to the large design margins included in the original nuclear power plant designs and in addition, to the technological advances that have been made to the nuclear industry. Power increases are now carried out by several nuclear utilities in the United States with the NRC’s concurrence. Current nuclear power plants are providing cheap, reliable and affordable electricity to help meet current energy growing demands. As a result of this, power uprate increases are encouraged. Current economic conditions strongly favor power uprates and plant life extensions. In the early 1990s, a limited power uprate program was initiated, but due to complex design reviews, this was not steadfastedly recommended during this time period. Nuclear Steam Supply Systems (NSSS) vendors performed a key role in this nuclear power uprate program. This paper discusses structural and piping qualification review required to achieve these power uprate programs, currently being performed by nuclear utilities in the United States.