Working of a Pressure Reactor

The basic principle is simple: nuclear energy is used to produce steam, the steam drives a turbine, and the turbine powers a generator, which produces electricity.

Pressure water reactor working

In a pressure water reactor, high pressure is created to keep the water in the reactor tank from boiling, even though it reaches a temperature of about 300° C at full force. This water is conducted to a steam generator and passes through thousands of small pipes. The heat in the pipes causes the water in the steam generator to turn to steam – which then drives the turbine. The turbine powers the generator, which in turn produces electricity.The reactor water is pumped back into the reactor tank and heated again. The steam from the turbine is cooled in a condenser, and the resulting water sent back into the steam generator and heated again.

(Animated Image Source: http://www.nrc.gov/reading-rm/basic-ref/students/animated-pwr.html)

1. The reactor

Uranium atoms are split inside the reactor, which heats the water. However, high pressure keeps the water from boiling even though it reaches a temperature of nearly 300° C.

2. The pressure vessel

A pressure vessel is used to control the pressure inside the reactor. Electric heat is applied to raise the pressure, and cold water to lower it.

3. The steam generator

The steam generator works as a heat exchanger, in which the very hot water from the reactor releases its heat and causes the water in the steam generator to boil and turn to steam.

4. The turbine

Steam is conducted into the turbine, causing the blades to rotate at speeds up to 3,000 rpm.

5. The transformer

A transformer converts the electricity into a high-voltage current. This is then sent to the power grid via high-tension wires.

6. The generator

The turbine powers a generator, which produces electricity.

7. The condenser

In the condenser, cold sea water running through a network of pipes cools the steam into water. This water is then pumped back into the steam generator.

8. Sea water

To cool the steam back into water, a huge amount of sea water is pumped into the condenser via pipes about the same diameter as a finger. When this water is pumped back into the sea, it is about ten degrees warmer than it was before it entered the condenser. The sea water circulates through a closed system, and never comes in contact with the reactor water.