Approach: Fault tree analysis

1
Approach Fault tree analysis
E0 Top event operational failure or
life-safety failure (two trees)
E0
Ei Basic event damage of individual equipment
E23
or - gate
and - gate
E2
E1
E3
(E0 occurs) if and only if (E1occurs OR both E2
and E3 occur)
2
Fault tree analysis (continued)
Mathematical equivalent of gates (independent
events)
O
I1
IN
O
I1
IN
For the example fault tree
3
Decision variables and top-event definitions
Events of interest and proposed Decision
Variables (DV)

• Life safety failure DVLSP(LSF T), where LSF
  is
• Occurrence of a life-threatening event, T
  planning period (alternatively DVLSP(LSFIM))
• Operational Failure DVOP(OF T) or P(OF IM),
  where OF is
• Repair or replacement time of critical equipment
  exceeds some threshold value DT0.
• Research products lost and the time to repeat the
  study is greater than some threshold value RT0.

Required performance level is specified by DVLS,
DVO, DT0, RT0
4
Fault tree illustration for an LSA laboratory
Operational Failure
Subject Die
Critical Equipment Failure
Data Lost
Env. Failure
Trauma
Microscope is broken
Data storage device is broken
Temp. Changes
Containment Failure
Basic event (Damage State)
Hazmat Release
Tube is broken

• To be refined upon consulting Comerios database,
  Comerio and LSA occupants

5
Expected Results

• Result of calculation of DVP(E0 IM) by
  applying theorem of total probability

• Result of calculation of DVP(E0 EDP)

1.0
1.0
DV
DV
0.0
0.0
x1
x2
x3
x1
x2
x3
IM
IM
Each point corresponds to a particular value of
the vector of EDP at the given level of IM
Where N is number of simulations at the level
IMxi, and the right part probabilities are all
conditioned on IM xi
6
What we would like from structure modeler
(Mosalam)
GM ID
SIM
EDP ID
EDP Value
Files in formats CSV, MDB, XLS.
7
What we would like from fragility testers
Fragility Parameters
Assembly ID
DS
EDP Type
Assembly Name
P1 (e.g. ?)
P2 (e.g. ? )
Files in formats CSV, MDB, XLS.