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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