Environmental Engineering Reference
In-Depth Information
Table 10. RCIC knowledge base
Feed
Pressure
Rate of revolution
Condenser water reserve
RCIC criticality values
L
L
L
L
H
L
M
L
L
H
L
M
M
L
H
L
M
M
M
M
…………………………………
H
H
M
H
L
depending on incoming BBN parent systems
condition change evidence using the CPT;
• Determination of conditions of the parent
systems (RCIC and EGRS) according to
evidences (facts) of their possible condition
(diagnostics task).
( = = [0.12 1.0 0.87
0.91] [0.87 0.55 0.87 0.66] [0.94 0.55
0.87 0.91]=0.55;
µ Y Crt Medium
1
( = = [0.87 1.0 0.87 0.91]
[0.94 0.66 0.53 0.55] [0.94 0.66
0.53 0.91]=0.87.
µ Y Crt
Low
1
In BBN probabilities of the reactor being
(S 3 ) in different conditions of set S 3 depending
on conditions of the parent systems (RCIC-S1,
EGRS- S 2 ) can be determined by the relation of
the following form:
Select d j * as a solution, for which,
*
d
µ
(
x x
,
, ...,
x
)
=
t
1
2
n
.(20)
d
max[
µ
(
x x
,
, ...,
x
)],
j
=
1
,
m t
,
=
1
,
m
.
j
P S
(
( )
k
)
=
P S
(
( )
k
/
S
( )
i
,
S
( )
j
)
P S
(
( )
i
)
P S
(
( )
j
)
1
2
n
3
3
1
2
1
2
i
j
(21)
Criticality state of EGRS is determined in a
similar manner. EGRS safety estimates are deter-
mined in the FLI block in terms of parameters of
its components (excess steam-gas mixture removal
bypass conduit, bypass conduit steam-gas mixture
signal indicator, steam-gas pressure chamber).
BBN block application. The complex of sys-
tems including the reactor (child system) and RCIC
and EGRS (parent systems) can be represented in
the form of BBN.
This approach uses BBN for:
where P S k
(
( )
3
)
- probability of S 3 being in k- th
( )
k
( )
i
( )
j
condition; P S
- a conditional prob-
ability of S 3 system in k- th condition given that
S 1 system is in i- th condition and S 2 system in
j- th condition. Conditional probabilities for BBN
are set by professional expert; P S
(
/
S
,
S
)
3
1
2
(
( )
i
)( (
P S
( )
j
))
1
2
- probability of S 1 (S 2 ) system being in i- th (j- th )
condition.
This approach predicts reactor safety state
without additional measurements of reactor pa-
rameters (pressure, temperature, etc.).
The block's output data are reactor safety
predictive estimate represented in the form of the
following probability distribution:
Reactor criticality condition prediction ac-
cording to the state of parent systems (RCIC
and EGRS). This involves recalculation of a
probability of the reactor child system being
in each of its possible criticality conditions
 
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