A nuclear power station has a safety system based on three inputs to a logic network. A
warning signal (S = 1) is produced when certain conditions in the nuclear power station
occur based on these three inputs:
Inputs
T
P
W
Binary values
1
0
1
0
1
0
Description of plant status
Temperature > 115°C
Temperature <= 115°C
Reactor pressure > 15 bar
Reactor pressure <= 15 bar
6
Cooling water> 120 litres/hour
Cooling water <= 120 litres/
hour
A warning signal (S = 1) will be produced when either a) OR b) are TRUE:
a) Temperature > 115°C AND Cooling water <= 120 litres/hour
b) Temperature <= 115°C AND (Reactor pressure > 15 bar OR
Cooling water <= 120 litres/hour)
Draw a logic diagram and truth table to show all the possible situations when the
warning signal (S) could be received. [45 marks]
