This session investigates the design, construction and operation of a new generation of nuclear power plants, both from a regulatory and technology viewpoint. Experience and future plans for digital automation systems in both growing and stable nuclear programs are discussed, with an eye towards how this experience can be applied to nuclear plants worldwide.

P027-“Use of Advanced Digital Controls in NPP Applications: A Case Study and Application to U.S. NPP Retrofits”

John Stevens, HF Controls, Korea Hydro and Nuclear Power, Ltd.

South Korea, through its nuclear operating arm, Korea Hydro and Nuclear Power, Ltd. (KHNP), has been one of the leading countries in the modern long term construction and operation of nuclear power plants. While standardizing on certain design approaches in the plant, KHNP continues to stress the need for the most reliable and cutting edge I&C technologies available for NSSS and BOP functions. Its specifications are among the most challenging in the world with regard to the requirements that must be met for the system to be supplied.

The Ulchin Units 5 & 6 (1000 MW each) nuclear power plants have been recently commissioned (2004 and 2005 respectively) with advanced digital control systems in the NSSS and BOP (which includes both safety and non-safety applications). The systems supplied met what the authors believe are the most rigorous performance and functional specification criteria in use in nuclear power plants today. These system designs are now proven, based on successful Ulchin 5&6 operations for the past 2 years, and can provide a basis for I&C upgrades in the USA.

The authors will highlight a number of the specification requirements, the rationale for same and the plant installation and operating experiences in the resultant supplied systems. As the existing U.S. nuclear fleet is faced with the prospect of upgrading legacy controls with digital controls, there are valuable lessons to be learned in the Korean experiences that can be applied to retrofits and even new U.S. plant designs.

The specification focus that guided the selection and project execution for the digital controls supplied for Ulchin was on several key areas: a) a modern and proven, state of the art digital control system, b)validation and verification of the owner’s engineer’s application design (for regulatory compliance); c)validation and verification of the system architecture and operation (to assure system performance meets intended use); d)system performance criteria (system response is critical to plant performance); e)global system reliability (HMI, control system components; long term support); f)functional segmentation (safety and non-safety; high integrity communication; minimizing propagation of failure modes.

The paper will review these key specification criteria, not only in context of a successful implementation for the Ulchin plant, but will also discuss applicability to the challenges of using digital controls in retrofit applications in U.S. nuclear power plants and in particular with regard to regulatory issues.

P025-”The Bottom Line Benefits of Digital Field Devices in Nuclear Power Plants”

Bill Fitzgerald, Fisher Controls

Over the last 5 years a number of nuclear power plants in North America have been involved in upgrading their field devices and related loops from old local pneumatic controls to modern, optimized systems featuring digital control valve positioners. This paper will summarize the reasons behind these modifications, and then present 5-10 case studies that provide guidance on optimizing the approach to these digital upgrades. The case studies will deal primarily with upgrades to the main feedwater and feedwater heater systems at plants such as St. Lucie, Turkey Point, Byron and Braidwood, Ft. Calhoun, South Texas Project and others. The paper will conclude with a detailed discussion on the ROI for each of the each of the digital upgrade projects, focusing on the investment required and the bottom-line benefits that resulted.