Diversity and Multi-Version Systems - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 200

six possible values (Table 3). The total number
of diversity type combinations, without consid-
eration dependencies among them is 54,000.
However, a significant part of these combinations
is infeasible. Our model represents all and only
feasible combinations of various diversity types.
Each path through the graph represents a set of
independent diversity combinations. There are no
dependencies among diversity values inside each
set.

The model contains 26 different paths with
374 feasible diversity combinations, as shown
in Table 6.
The model allows choice of optimal design
decisions with various types of diversity. The
specific way of using the model depends on se-
lected criteria. For example, if we would like to
minimize cost of the design decision, the model
allows easy cost calculation of each feasible di-

Table 6. Feasible combinations of diversity types

Path TC MC FC TP MP L TO Number

of Feasible
Combinations

1 TC1, TC3 MC1, MC3 FC1, FC3 TP1 MP1, MP2 L1 TO1 16

2 TC1, TC3 MC1, MC3 FC1, FC3 TP1 MP1, MP2 L2, L3 TO2 32

3 TC1, TC3 MC1, MC3 FC1, FC3 TP2 MP1, MP2 L1 TO1 16

4 TC1, TC3 MC1, MC3 FC1, FC3 TP2 MP3, MP4 L2, L3 TO2 32

5 TC1, TC3 MC3 FC4 TP1 MP1, MP2 L1 TO1 4

6 TC1, TC3 MC3 FC4 TP1 MP1, MP2 L2, L3 TO2 8

7 TC1, TC3 MC3 FC4 TP2 MP1, MP2 L1 TO1 4

8 TC1, TC3 MC3 FC4 TP2 MP3, MP4 L2, L3 TO2 8

9 TC1, TC3 MC3 FC3, FC5, FC6 TP3, TP5 MP1, MP2 L1 TO1 24

10 TC1, TC3 MC3 FC3, FC5, FC6 TP3, TP5 MP1, MP2 L2, L3 TO2 48

11 TC1, TC3 MC3 FC3, FC5, FC6 TP4 MP3, MP4 L1 TO1 12

12 TC1, TC3 MC3 FC3, FC5, FC6 TP4 MP3, MP4 L2, L3 TO2 24

13 TC5, TC6 MC4, MC5 FC4 TP1 MP1, MP2 L5 TO2 8

14 TC5, TC6 MC4, MC5 FC4 TP2 MP3, MP4 L5 TO2 8

15 TC5, TC6 MC4, MC5 FC3, FC5, FC6 TP3, TP5 MP1, MP2 L5 TO2 24

16 TC5, TC6 MC4, MC5 FC3, FC5, FC6 TP4 MP3, MP4 L5 TO2 24

17 TC2 MC1, MC2 FC1, FC2 TP1 MP1, MP2 L4 TO3 8

18 TC2 MC1, MC2 FC1, FC2 TP2 MP3, MP4 L4 TO3 8

19 TC2 MC3 FC4 TP1 MP1, MP2 L4 TO3 2

20 TC2 MC3 FC4 TP2 MP3, MP4 L4 TO3 2

21 TC2 MC3 FC3, FC5, FC6 TP3, TP5 MP1, MP2 L4 TO3 12

22 TC2 MC3 FC3, FC5, FC6 TP4 MP3, MP4 L4 TO3 6

23 TC4 MC4, MC5 FC4 TP1 MP1, MP2 L4 TO3 4

24 TC4 MC4, MC5 FC4 TP2 MP3, MP4 L4 TO3 4

25 TC4 MC4, MC5 FC3, FC5, FC6 TP3, TP5 MP1, MP2 L4 TO3 24

26 TC4 MC4, MC5 FC3, FC5, FC6 TP4 MP3, MP4 L4 TO3 12

Total 374