Pressurized Water Reactor (PWR) Power Plant - The Basic Concept

In Pressurized Water Reactor (PWR) water or heavy water is used as both coolant as well as moderator. The below figure shows basic diagram of Pressurized Water Reactor.
Pressurized Water Reactor Power Plant |
Pressurized Water Reactor Power Plant

This reactor uses enriched Uranium.
Before starting the reactor, water in pressurizer is boiled and converted into steam by electric heating coil. In order to prevent the boiling of water in the core, it is kept under the pressure of about 130-150 bar. It helps in absorbing the heat by water in the liquid state in the reactor. The heat energy absorbed by the water in the reactor is used for converting the water in to the steam in heat exchanger.
This steam is used in a conventional way in the steam power plant cycle. Thus, power in not only generated through reactor but also through steam power plant.
The condenser condenses hot steam from steam power plant and cools it down.
The water coolant from heat exchanger is recirculated to the reactor with the help of coolant pump.
These power plants are compact and its cost is reduced since it uses water as coolant as well as moderator.However, high pressure in primary circuit of water absorbing heat in the reactor requires a stronger shell which increases its cost.
In these reactors, the water flowing through the reactor becomes radioactive.
Therefore this primary circuit must be heavily shielded to protect the operators.

Advantages of Pressurized Water Reactor (PWR):

1. Water is used as both coolant as well as moderator which is cheap and easily available.
2. This reactor is compact.
3. Fission product remains contained in the reactor.
4. Small number of control rods are required.

Disadvantages of Pressurized Water Reactor (PWR):

1. Its capital cost is high since the reactor and primary circuit works under pressure.
2. Costly shielding is required to shield the operators in primary circuit since the coolant becomes radioactive.
3. Fuel suffers from radiations. Therefore, its reprocessing is difficult.
4. Only saturated steam can be generated in secondary circuit, therefore the efficiency of the plant is low.
5. Sever corrosion problems.
6. Plant needs to be shut down for fuel charging.

Sujit Kadus

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