Several nuclear power plant water systems are termed closed

Several nuclear power plant water systems are termed ‘closed loop’. What is meant by this term as opposed to ‘open loop’?

Solution

In a closed loop power plant, the same working fluid is circulated again and again within the turbine but in open loop power plants, the working fluid i.e; genereally the air-fuel mixture is replaced again and again.

The main differences between the two:
1. Closed loop gives higher thermal efficiency for a given lower and upper temperature fluids.

2. Closed loop power plants are generally smaller in size for the same power output.

3. Closed loop power plants have complex structure and are costly as compared to simplicity and less cost of the open loop power plants.