ELECTROMAGNETIC COMPATIBILITY OF DIGITAL INSTRUMENTATION AND CONTROL SYSTEMS IN NUCLEAR POWER PLANTS

摘要

Rising maintenance costs, coupled with a lack of spare partsrnfor instrumentation and control (I&C) systems no longer supportedrnby the original manufacturer, are leading to an increasing use ofrndigital I&C equipment in nuclear power plants (NPPs). Thernpotential for disruption of safety-related digital I&C systems byrnelectromagnetic interference/radio-frequency interferencern(EMI/RFI) is an issue of concern for the nuclear industry. In thernabsence of significant operational experience, the best availablernindication of the potential vulnerability of advanced digital safetyrnsystems to EMI/RFI comes from environmental testing of anrnexperimental digital safety channel (EDSC) by the Oak RidgernNational Laboratory (ORNL). The EDSC is a prototypical systemrnrepresentative of advanced reactor safety system designs withrnregard to architecture, functionality and communication protocols,rnand board and component fabrication technologies. Anrnunderstanding of the electromagnetic environment to be expectedrnfor NPPs can be drawn from ORNL’s long-term survey of ambient results from these research efforts is reported in this paper. Thernlessons learned from the EMI/RFI survey and the EDSC testsrncontribute significantly to determining the best approach tornassuring electromagnetic compatibility for the safety-related I&Crnsystems in NPPs.rnEMI/RFI conditions at several plant sites. A summary of the