BS EN IEC 60709:2019 pdf free.Nuclear power plants – Instrumentation, control and electrical systems important to safety – Separation.
design extension condition postulated accident conditions that are not considered for design basis accidents, but that areconsidered in the design process of the facility in accordance with best estimate methodology,and for which releases of radioactive material are kept within acceptable limits. Designextension conditions comprise conditions in events without significant fuel degradation andconditions in events with melting of the reactor core [SouRCE: IAEA Safety Glossary, edition 2016]
distance <separation by> placement of the components being protected sufficiently far away from one another so as toensure that they cannot be simultaneously damaged by the considered event.
diversity presence of two or more independent (redundant) systems or components to perform anidentified function, where the different systems or components have different attributes so asto reduce the possibility of common cause failure, including common mode failure [SOURCE:IAEA Safety Glossary, edition 2016]
division collection of items, including their interconnections, that form one redundancy of a redundantsystem or safety group. Divisions may include multiple channels.
electrical isolation electrical isolation is used to prevent electrical failures in one system from affectingconnected systems. Electrical isolation controls or prevents adverse interactions betweenequipment and components caused by factors such as electromagnetic interference,electrostatic pickup，short circuits, open circuits，grounding,or application of the maximumcredible voltage (AC or DC) [SOURCE:IAEA SsG-34 and ssG-39,2016]
electromagnetic compatibility EMC ability of an equipment or system to function satisfactorily in its electromagnetic environmentwithout introducing intolerable electromagnetic disturbances to anything in that environment.
electromagnetic interference EMI
degradation of the performance of an equipment,transmission channel or system caused byan electromagnetic disturbance [SOURCE: IEC 60050-161:1990，161-O1-06]
independence condition that exists when successful completion of a system’s required functions is notdependent upon any behaviour including failures and normal operation of another system, orupon any signals, data, or information derived from the other system
Note 1 to entry: The following definition is to be found in the IAEA Safety Glossary, edition 2016 for ” independentequipment” “Equipment that possesses both of the following characteristics: a) The ability to perform its requiredfunction is unaffected by the operation or failure of other equipment; b) The ability to perform its required functionis unaffected by the occurrence of the effects resulting from the initiating event for which it is required to function”.This IAEA definition is limited to equipment but is consistent with the definition given in this document.
isolation device device in a circuit that prevents malfunctions in one section of a circuit from causingunacceptable influences in other sections of the circuit or other circuits [SoURCE:IEC 62808:2015,3.4].BS EN IEC 60709 pdf download.