EFTed - Event/Fault Tree Editor and Display

Edit Mode

In edit mode, EFTed allows the event trees and underlying fault trees to be changed in a variety of ways. The menu bar at the top of the event tree window allows users to do the following:

Add/Edit consequences
Add a new Event Tree
Edit Event Tree properties (its name and its description)
Delete an Event Tree

Within the event tree that is shown, columns can be added or deleted and sequences can be added or deleted. Below is the event tree for "LPLA", a loss of off site power and a loss of coolant accident at the same time. The edit targets can be toggled on/off using "Display/Toggle Edit Targets" menu bar.

The following editing actions listed in the table below can be made to an event tree in edit mode.

Desired Edit	Mouse Action	Where	Comment
add a column	left click	green arrow	The arrow shows where the new column will be placed. One can add a column based on an existing gate or a new gate.
delete a column	right click	green arrow	Only on columns that have no forks.
add a failure path	left click	green fork	Duplicates consequence of above branch.
delete a failure path	left click	red circle-x	Only works on undeveloped branches.
change consequence	left click	consequence	Can ony choose from existing list. To add new consequences, first define them using the "Edit/Add-Edit Consequences" menu bar.
change simplefailure probability	left click	probability	Actually, this is associated with the top-level gate, not the event tree.
view fault tree	left click	column name	Gives editable fault tree in separate window.

For editing fault trees, right clicking on any gate or event will show a pop-up a menu with five choices:

copy - this selects the gate for copying. When copying a basic event, both the old and new events will be shown. When copying a gate, the gate will move to its own fault tree window and both the old and new locations of that gate will be replaced by the TRANSFER gate symbol.
paste - this will paste the gate or event currently in memory as a child of selected gate
delete - will delete this gate
add input - will bring up a screen allowing user to specifiy child gates and events
edit properties - for changing gate description, logic type (AND or OR)

Of course, not all of the above options will be enabled for each type of gate.

Six different operators can be used. They are listed in the table below.

name	inputs	failed if ...
and	>0	all inputs are failed
or	>0	at least one input is failed
not	1	input is not failed
nand	>0	at least one input is not-failed
nor	>0	all inputs are not-failed
xor	2	only 1 input is failed

Some editing options are also available without the pop-up menu. A gate or basic event can be moved to a different location on the tree by left-clicking and dragging it to its new parent. Clicking on a TRANSFER gate will bring up a separate window for that gate.

When done editing, use the menu bar "File/Save" to save your changes. Use "File/Exit" to leave the program.

Oak Ridge National Laboratory, 2004

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