Nuclear Reactor or Nuclear Energy / Power [ Part - 2 ]

Nuclear reactor

4. Control rod:

 

The control rod or control rod of a reactor is usually made of boron metal. It is glabrous and leaf-shaped. Its main function is to absorb the extra neutrons during the splitting of nuclear energy. This control rod controls the splitting process by going up and down through the holes in the reactor core.

 

 

Types of control rods:

 

According to the rules of use, the control rod is divided into two parts, namely:

 

(A) Safety control rod and

(B) Leaf-shaped control rod.

 

When the work of the nuclear reactor is stopped, the safety control rod is opened and kept outside. Again, when the chain reaction of nuclear fuel has to be started, if this control rod is to be inserted in the reactor, the chain reaction of nuclear fuel will start.

 

The leaf-shaped control rod, on the other hand, is always inserted into the reactor, and when the rod is lowered or lifted from the bottom to the top, the reaction in the reactor continues.

However, if at any time the leaf-shaped control rod accidentally gets stuck in the reactor and generates strong waves, then the scraping method of the reactor is suspended. The scrambling method of the reactor refers to the use of an automatic shut-off method or a quick push to remove the control rod and suspend the splitting process.

 

 

5. Coolant:

 

The function of the coolant is to keep the cell of the reactor cool at a certain temperature and to carry the heat through a heat exchanger in contact with a lot of heat and to evaporate the water from its direct contact. We know that the mechanical energy of these substances is converted into thermal energy when the surrounding matter collides with the atoms and neutrons produced by the chain reaction inside the reactor. The coolant is used inside the reactor to dissipate the heat generated. The coolant is pumped.

 

The water in the heat exchanger exchanges heat as the coolant flows through the pipe between it. This reduces the heat of the coolant a bit and it enters the reactor again through the pump. The heat from the heat exchanger, on the other hand, evaporates from the heat of the coolant, giving the steam turbine a rotational motion. The generator connected to this turbine shaft then starts generating electricity. Light water or heavy water with different types of gases and liquid metals are used as coolant. Here, various gases include air, helium, carbon-dioxide, and liquid metals include sodium, lithium, etc.

 

The coolant of the reactor must have some special properties. E.g.

 

·         High specific heat

·         High density,

·         High boiling point etc.

·         On the other hand its alkalinity, acidity and

·         The adhesive must be zero.

 

 

6. Radiation shield:

 

The gamma rays emitted as a result of the nuclear chain reaction generate excessive heat and are highly toxic. The radiation shield reduces this heat and prevents toxicity from coming out. In addition, the radiation shield is used as a shield to protect the walls of the reactor container from the outbreak of neutrons, alpha, beta or gamma rays.

 

The radiation shield is made of ordinary steel metal and is surrounded by a layer of clay concrete or reinforced brick wall. It is good to know that shielding walls made of concrete are also cheap and suitable for all types of toxicity.

 

 

Reactors used in nuclear power plants

 

Considering the nature of the reactor, the following eight types of reactors are used in nuclear power plants, namely:

 

1. Pressurized water reactor (P.W.R)

2. Boiling water reactor (B.W.R)

3. Gas cooled reactor (G.C.R)

4. Fast breeder reactor (Fast breeder or F.B.R),

5. Sodium graphite reactor (S.G.R)

6. Power reactor

7. Homogeneous reactor and

8. Shipping port reactor

 

However, the homogeneous reactor and the shipping port reactor are not used as reactors at the central nuclear power plant.

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