Logic flowgraph: a new approach to process failure modeling and diagnosis for disturbance analysis applications
This dissertation presents a new methodology intended to provide a more efficient way of constructing failure models for use in a diagnosis oriented disturbance analysis system. Called the Logic Flowgraph Methodology (LFM), this approach, which represents a considerable development beyond the capabilities of previous models, is also useful in reliability and risk analysis applications. Like the digraph method, LFM produces process models, in which the fundamental units of nodes and edges are used to represent respectively process variables and causality relations. In LFM, however, special tests of symbols and representation rules are used to achieve a level of modeling capability and flexibility that can facilitate the analysis of complex processes in real-life situations. Once a process flowgraph model has been derived, it is possible to obtain from it any fault-tree structure whose top-event can be expressed as a weak or strong perturbation on one of the variables constituting a flowgraph node. This fault-tree construction is performed automatically by a computer routine, accepting as inputs the logic flowgraph topology and the top-event(s) of the desired fault-tree(s). In an on-line disturbance analysis application, this routine will also accept as input a suitable set of field instrumentation signals. Using this information, the computer will identify the disturbance prime cause(s) by logically developing only those tree-branches that the instrumentation indicates as active. In reliability or risk analysis applications, however, the desired fault-tree(s) will be developed to its (their) full extent.
- Research Organization:
- California Univ., Los Angeles (USA)
- OSTI ID:
- 6308397
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220900* -- Nuclear Reactor Technology-- Reactor Safety
ELECTRONIC CIRCUITS
FAILURES
FAULT TREE ANALYSIS
LOGIC CIRCUITS
MATHEMATICAL MODELS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
REACTOR COMPONENTS
RELIABILITY
RISK ASSESSMENT
SYSTEM FAILURE ANALYSIS
SYSTEMS ANALYSIS
THERMAL POWER PLANTS