Document: NUREG-0800
Document ID: 4f097781-0d4c-4b5b-be06-a3cd19ae9fe8
Document Type: srp
Title: Revision 5 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070660430.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
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Content:
g, and interconnections combined with failures that the circuit may credibly experience. On-line testing - Testing performed on an operable system. Operable - A system, subsystem, train, component, or device is operable when it is capable of performing its specified safety function(s) and when all necessary attendant instrumentation, controls, normal or emergency electrical power, cooling and seal water, lubrication, and other auxiliary equipment that are required for the system, subsystem, train, component, or device to perform its specified safety function(s) are also capable of performing their related support function(s). Performance - The degree to which a system or component accomplishes its designated functions within given constraints, such as speed, accuracy, or memory usage [IEEE Std 610.12]. Periodic tests - Tests performed at scheduled intervals to detect failures and verify operability [IEEE Std 338]. Periodic tests include surveillance tests. Predeveloped software (PDS) - Software that already exists, is available as a commercial or proprietary product, and is being considered for use in a computer-based function [IEC Std 880, Supplement 1 draft]. Commercial off-the-shelf (COTS) software is a subset of PDS. Protection systems - Those I&C systems which initiate safety actions to mitigate the consequences of design basis events. The protection systems include the reactor trip system (RTS) and the engineered safety features actuation system (ESFAS). Reactor trip systems (RTS) - Those I&C systems that initiate rapid control rod insertion to mitigate the consequences of design basis events. Reliability (as a software functional characteristic) - The degree to which a software system or component operates without failure. This definition does not consider the consequences of failure, only the existence of failure. Redundancy - Multiple SSC’s each capable of performing a given function. Requirements Traceability Matrix (RTM) - An RTM shows every