Development of an Update to ISA S67.04 and RP 67.04: 'Setpoints for Nuclear Safety-Related Instrumentation for Nuclear Power Plants'

摘要

The purpose of this paper is to provide an overview of the update to International Society of Automation (ISA) Standard ISA S67.04-2006, "Setpoints for Nuclear Safety-Related Instrumentation for Nuclear Power Plants," (Reference 1) and ISA RP 67.04-2000, "Methodologies for Determination of Setpoints for Nuclear Safety-Related Instrumentation" (Reference 2). Significant advances have occurred on the utility, Nuclear Steam Supply System (NSSS) vendor, and regulatory side, related to improved techniques for analysis and monitoring. These and other changes, including those related to Technical Specifications and surveillance interval extensions, are being included in the latest update to this primary standard for setpoint control in nuclear plants in the U.S. and around the world. In 2016, the ISA S67.04 Committee agreed to proceed with a revision to this Standard and Recommended Practice, with major updates in the following areas: 1. Definitions - Updates for improved definitions based on TSTF-493, Rev 4 (Reference 3), RIS-2006-17 (Reference 4) and NRC updated Regulatory Guide (RG) 1.105 (Reference 5) 2. 95/95 - Updates based on improved guidance on the development of component input data and analysis techniques for 95% probability/95% confidence calculations 3. TSTF-493, RJS 2006-17 updates for Technical Specification input and to support changes 4. NRC input from updates in the Regulatory Guide 1.105 (Reference 5) and Branch Technical Position BTP-7-12 (Reference 6) revision process. 5. Improved guidance from the Electric Power Research Institute (EPRI) in References 7, 8 and 9. These standards are being updated with a new version anticipated to be issued as a draft in 2017 and submitted for ISA approval in 2019.