Logic diagrams

An example of a faiilt tree logic diagram using AND and OR gate logic is shown in Fig. 26-5. 

Consequence Estimation Given that an incident (release of material or energy) has been defined, the consequences can be estimated. The general logic diagram in Fig. 26-6 illustrates these calculations for the release of a volatile hazardous substance. 

FIG. 26-6 Overall logic diagram for consequence analysis of volatile hazardous suhstances. (CCFS-AlChK, 1989, p. 60.)... 

Step I Defining the System - Collect the information needed to perform the analysis. Information needs include system descriptions, schematics, P IDs, logic diagrams, and operating procedures. Step 2 Establishing Inputs/Outputs - Every GO model begins with at least one input aiul may have many interfacing inputs. The output of the model is determined by the success criteria. 

Fig. 6.3-3 Core Damage Master Logic Diagrams for Indian Point 2 and 3 Nuclear Power Stations.

Hazard Identification, the main sources of ammonia that could release are identified and the initiating events (IE) that can cause accidents leading to the release of ammonia are determined. Three methods used for IE identification were Master Logic Diagram, checklists, and HAZOP... 

Figure 15.6.1. Logic diagram lo couiplele for Preliminary Hazard Analysis (PHA).

Logic Diagram Methods (Fault Tree Analysis, Event Tree Analysis, Cause-Consequence Analysis, Human Reliability Analysis, Success and Failure Trees, etc,)... 

Figure 9.6. Simple fault chart (logic diagram)...

The flat tire example is pictured using a fault tree logic diagram, shown in Figure 11-12. The circles denote basic events and the rectangles denote intermediate events. The fishlike symbol represents the OR logic function. It means that either of the input events will cause the output state to occur. As shown in Figure 11 -12, the flat tire is caused by either debris on the road or tire failure. Similarly, the tire failure is caused by either a defective tire or a worn tire. 

A widely used method to study event sequences that can lead to incidents involves logic diagrams, an example of which is shown in Figure 4.1. Through the method illustrated in the figure, it is determined that a runaway reaction will happen only if both the cooling system fails and the reactor contents... 

Three hazard evaluation procedures using logic diagrams are (1) fault-tree analysis (FTA), (2) event-tree analysis (ETA), and (3) cause-consequence analysis (CCA). Appropriate references are [2,3,251,261]. 

Event tree (analysis) a graphical logic diagram which identifies and sometimes quantifies the frequencies of possible outcomes following an initiating event. 

Figure 1-1—Rotor Lateral Analysis Logic Diagram...

The decision process to determine when to provide drainage for a process unit or structure is illustrated in Figure 8-1, Drainage Logic Diagram. 

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