EFcalc - Event/Fault Tree Calculator |
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Describes the fault tree logic in terms of equations. The equations are specified by a variable name (system or intermediate gate name), an operator ('and', 'or', 'not', 'nand', 'nor', 'xor'), then the shortnames of the arguments (intermediate gates or basic events listed in the *.bas file). After all of the arguments, a long name in quotes describing the gate is given. Shortnames must be simple strings and may not contain spaces, quotes, or other special characters. If no longname is desired, an empty set of quotes must be given.
loop or power control tformers "Off-Site Power (1 of 29)"
ep or control bothtrains sws "On-site Power (28 of 29)"
bothtrains and traina trainb "Diesel Systems"
traina or busesa tadiesel "Train A Diesel Power"
trainb or busesb tbdiesel "Train B Diesel Power"
tadiesel or DT1A1 DT1A2 GTA SAA D1A "Diesel System A (r8 of 29)"
tap or busesa powera "Train A Power (r7 of 29)"
powera and tadiesel loop "Power Supply A"
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 |
Gate equations can also include "not"'s just before a child's gate/event name. The symbols '-' and '/' can both be used for the not and must imeadeately precede the name (no space). The following example are legal equations:
top or gate1 gate2 gate3 gate4 gate5 gate6 "top level gate"
gate1 and a b -c -d "and gate"
gate2 or a b -c -d "or gate"
gate3 not k "not gate"
gate4 nand e f -g -h "nand gate"
gate5 nor e f -g -h "nor gate"
gate6 xor i j "xor gate"
Oak Ridge National Laboratory, 2004