Normally expected event

In addition, Bill Johnson used a scroll as a normally expected event and an oval as a satisfactory event. The normally expected event distinguishes events that are typically a part of any system, such as change and normal variability. The satisfactory event describes events that may be accident causal factors but are a necessary part of the operation, like functional (part of the system) people or objects in the energy channel. Also, in addition to using the traditional transfer symbol (a triangle), the MORT chart includes capital letters as drafting breaks and small ellipses as risk transfers (Fig. 18-3). 

Figure 18-1 Event Symbols. The General Event symbol, Basic Event symbol, and Undeveloped Terminal event symbol are the same as commonly used for other fault trees. The use of the stretched circle for a Satisfactory Event and the scroll for a Normally Expected Event are unique to the MORT chart.

External everrt An event which is normally expected to occur. 

Modified ADL Usage Not used as even events normally expected to occur c m lead to an uiidesired outcome and data may not be any more accurate than for any other type of event... 

Example 24 Consider as an example the set of 19 Monte Carlo generated, normally distributed values with a mean = 2.25 and a standard deviation = 1.43 used in Section 1.8.1 Table 1.24 is constructed in six steps. The experimental (observed) frequencies are compared with the theoretical (expected) number. The critical x -value for p = 0.05 and/ = 4 is 9.49, thus no difference in distribution function is detected. Note that the first and last classes extend to infinity it might even be advisable to eliminate these poorly defined classes by merging them with the neighboring ones is found as 1.6648 in this case the critical x is 5.991. Columns zi, Zr, ACP, expected events, and x are provided in program HISTO, option (Display) ... 

Secondary fault. An event with no further development. Normally expected to happen. 

However the B-cell response to PWM is dependent on T-cell function, and therefore completely normal responses to PWM are not necessarily the expected event. Indeed, we have noted preserved but diminished... 

For normal system operation missile launch would be expected when aU of the following conditions are successful (a) launch power is made available, (b) interlock 1 closure occurs, (c) interlock 2 closure occurs, and (d) interlock 3 closure occurs. The FT models these normal intended events occurring prematurely or inadvertently due to system failures. 

Normal design events encompass events that the SNPP would be expected to experience during the course of normal operation. 

Normal design events encompass events that the GTR was expected to experience during the course of normal operation. All of the SNPP design events listed in Section 11.2 are applicable to the GTR, although the GTR most likely will experience many more cycles for each transient. Transients are only listed below if there is a significant difference between the GTR and SNPP design events or if the design event is unique to the GTR. 

Site characterization studies include a surface-based testing program, potential environmental impact, and societal aspects of the repository. Performance assessment considers both the engineered barriers and the geologic environment. Among features being studied are the normal water flow, some release of carbon-14, and abnormal events such as volcanic activity and human intmsion. The expected date for operation of the repository is 2013. 

Quantitative risk analysis is a forecast concerning the degree of belief associated with the occurrence of future events. It normally focuses on those classes of events that are rarely expected to occur at a facility. However, because the potential consequences of such events may be so great, the possibility that the events could occur at all gives rise to concern. When a QRA generates results that reflect a very small likelihood of an event and confirm the suspicion that the event could have a severe impact, these questions inevitably arise What does it all mean What should I do about it ... 

An event or accident whose expected frequency is very small. The event is not expected to occur during the normal life of a facility or operation... 

Observations of field activities are performed by one or more Field Scientists. Normally, each volunteer worker is observed by an individual Field Scientist. The Field Scientist must remain with the worker at all times and closely observe such activities as loading the chemical, spraying the field, harvesting, scouting, and cleanup activities. The Field Scientist should remain at a safe distance from the worker to avoid any serious exposure to the pesticide which may occur during the course of the replicate. Protective equipment may be necessary for the Field Scientist depending on expected exposure levels and the toxicity of the product. In any event, the Field Scientist should have anticipated the risk of close observation and be aware of what protective measures are necessary. 

---