Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
CFR Part: 
CFR Title: 

Content:
change in the environment that results in the failure of another system or component. Functional dependencies include the following examples: • Shared component dependencies (e.g., systems or system trains that depend on a common intake or discharge valve), • Actuation requirement dependencies (e.g., systems that depend on common actuation signals, common actuation circuitry, or common support systems like AC or DC power or instrument air for initiation or actuation) and conditions needed for actuation (e.g., low RPV water level), • Isolation requirement dependencies (e.g., conditions that could cause more than one system to isolate, trip, or fail), including environmental conditions (temperature, pressure, and/or humidity), temperature and pressure of fluids being processed, water level status, and radiation levels, • Power requirement dependencies (e.g., systems that depend on the same power sources for motive power), • Cooling requirement dependencies (e.g., systems that depend on the same room cooling subsystem, or the same lube oil cooling subsystem, or systems that depend on the same service water or component cooling water train for cooling), • Indication requirement dependencies (e.g., systems that depend on the same pressure, temperature, or level instrumentation for operation), • Phenomenological effect dependencies (e.g., conditions generated during an accident sequence that influence the operability of more than one system), including generation of harsh environments that result in protective trips of systems, loss of pump net positive suction head (NPSH) when containment heat removal is lost, clogging of pump strainers from debris generated during a LOCA, failure of components outside the containment following containment failure attributable to harsh environment inside the containment, closure of safety relief valves in BWRs on high containment pressure, and coolant pipe breaks or equipment failures following (or resulting from)