Nuclear Executive Update   
An EPRI Progress Report, January 2011
TECHNICAL HIGHLIGHTS
Gold Card Project Targets Improved Circuit Card Reliability

Electronic circuit card performance at nuclear power plants has prompted the development of a life-cycle management plan to improve performance and reduce potential plant impacts.

EPRI is developing a life-cycle management plan to increase the reliability of circuit cards and components, reduce the likelihood of forced outages caused by circuit card failures, and provide guidance to help determine when and if the circuit card should be replaced, reengineered, or upgraded to digital technology.

 

More than three-fourths of nuclear plant scrams are equipment-related, according to INPO analyses. Source: INPO Topical Report 10-70, Attachment 3. Note: INPO reports are only available to INPO members.

 

Printed circuit cards used in I&C systems are aging, and their rate of failure has increased. A 2010 analysis by the Institute of Nuclear Power Operations indicated that electronic circuit cards are a significant contributor to power plant scrams and unit derates.

Failure of I&C systems due to degradation of component circuit cards can have an immediate negative impact on plant safety, performance, reliability and/or availability. While instrumentation and control (I&C) personnel are familiar with the construction and operation of printed circuit cards used in I&C systems, they are typically less familiar with board-level failure mechanisms and component failures. To manage these electronic parts better and adequately plan for their ultimate replacement, plant personnel must better understand their aging and failure mechanisms.

EPRI is developing tools to improve circuit card reliability. Industry best practices and lessons learned for monitoring, testing, diagnosing, and estimating remaining life of circuit cards will be incorporated into these tools. Major products will include:

  • Life-cycle management guidance for circuit cards through a “Gold Card” project. EPRI published the first part of the life-cycle management plan guidance in an interim technical report in December 2010 (1021080). The final report will be published in the fourth quarter of 2011. The report provides guidance to increase the reliability and operating life of existing circuit cards and components. For example, the report establishes guidelines for the proper handling of printed circuit cards and their components. Electrostatic discharge from static electricity on a person’s body can cause dielectric failure due to open or short circuits in sensitive components. The use of shielding material and proper grounding practices are important in preventing electrostatic discharge.
  • Guidance for aging management of circuit cards and components based on Électricité de France (EDF) experience. EDF laboratories have been collecting and analyzing circuit card failure data cards for years.
  • Updates to two EPRI reports: Collected Field Data on Electronic Parts Failures and Aging in Nuclear Power Plants (1003568) and Guidelines for the Monitoring of Aging of I&C Electronic Components (1008166). These updates include new information on observed failures, aging mechanisms, failure precursors, and description of tools and techniques that can be used off-line to assess the aging of passive components based on EDF operating experience and research.

For more information, contact Jim Heishman at 704-595-2768 or jheishman@epri.com or Joseph Naser at 650-855-2107 or jnaser@epri.com.