QUALIFICATION OF MICROPROCESSOR-BASED COMMERCIAL-OFF-THE-SHELF (COTS) EQUIPMENT FOR NUCLEAR POWER PLANT SAFETY SYSTEM APPLICATIONS

摘要

As obsolescence of older instrumentation and control (I&C) equipment drive the nuclear industry to upgrade to microprocessor-based and other advanced technologies, the qualification of commercial-off-the-shelf (COTS) computer systems for safety applications in nuclear power plants has become an important issue. Currently, the qualification of existing COTS computer systems is addressed in IEEE Std 7-4.3.2-2003, "IEEE Standard Criteria for Digital Computers in Safety Systems of Nuclear Power Generating Stations." This paper examines IEEE Std 7-4.3.2-2003 from the specific standpoint of its adequacy for environmental qualification of COTS computer systems for safety applications in nuclear power plants. The paper also briefly examines integrated circuit (IC) technology trends and their potential for survivability in the harsh (radiation) environment of nuclear power plants. It is argued that for computer/microprocessor-based systems, it makes good sense to explicitly require testing in addition to the other quality assurance mechanisms in place. The concern is that Sect. 5.4.1, "Computer System Testing," and Sect. 5.4.2, "Qualification of Existing Commercial Computers," could be treated as an either/or choice (i.e., under certain circumstances Sect. 5.4.2 would prevail in lieu of Sect.5.4.1).