IEEE Std 1819-2016 pdf download – IEEE Standard for Risk-Informed Categorization and Treatment of Electrical and Electronic Equipment at Nuclear Power Generating Stations and Other Nuclear Facilities.
Risk-Informed Safety Classifcation -1 (RISC-1): Electrical and electronic systems and components (EE- SCs) that are Class 1E and that the risk-informed categorization process determines are signifcant contribu- tors to plant safety. RISC-1 EESCs perform their safety-signifcant functions consistent with the categoriza- tion process, including those safety-signifcant functions that go beyond the functions defned as Class 1E for which credit is taken in the categorization process. (EESCs that are Class 1E and perform safety-signifcant functions.) Risk-Informed Safety Classifcation -2 (RISC-2): Electrical and electronic systems and components (EE- SCs) that are defned as non-Class 1E, although the risk-informed categorization process determines that they are signifcant contributors to plant safety on an individual basis. Though some RISC-2 EESCs may not have existing special treatment requirements, the focus for RISC-2 EESCs is on the safety-signifcant functions for which credit is taken in the categorization process. (EESCs that are non-Class 1E and perform safety-signif- cant functions.) Risk-Informed Safety Classifcation -3 (RISC-3): Electrical and electronic systems and components (EE- SCs) that are defned as Class 1E, although the risk-informed categorization process determines that they are not signifcant contributors to plant safety. Special treatment requirements may be reduced for RISC-3 EESCs and replaced with alternate treatments. These alternate treatments are intended to provide reasonable conf- dence that these EESCs can perform their Class 1E functions under design-basis conditions, albeit at a reduced level of assurance compared to the current special treatment requirements. (EESCs that are Class 1E and per- form low safety-signifcant functions.) Risk-Informed Safety Classifcation -4 (RISC-4): Electrical and electronic systems and components (EE- SCs) that are defned as non-Class 1E, and that the risk-informed categorization process determines are not signifcant contributors to plant safety.