101. What are the desirable properties of a good moderator?

• It must be as light as possibleIt must slowdown the neutron as quick as possible
• It must have resistance to corrosion
• It must have good machinability
• It must have good conductivity and high melting point

102. What are the desirable properties of a coolant?

• It should not absorb neutron
• Have high chemical and radiation stability
• Non-corrosive
• Have high boiling point
• Non-toxic

103. Name few types of reactors.

Fast reactors, Thermal reactors, natural fuel reactors, Enriched Uranium reactors, water moderated reactors, heavy water moderated reactor, graphite moderated reactor, gas cooled reactors and Sodium cooled reactors.

104. What are the advantages using CO2 as coolant?

• Gases do not react chemically with the structural materials
• Gas can attain any temperature for a particular pressure
• They do not absorb neutron
• The leakage of gas will not affect the reactivity
• The gas coolant provides best neutron economy

105. What are the advantages of breeder reactors?

• It gives high power density than any other reactor
• High breeding is possible
• High burn-up of fuel is achievable
• The operation of the reactor is not limited by Xe poisoning

106. What are the demerits of breeder reactor?

• Highly enriched fuel is required
• Control is difficult and expensive
• Safety must be provided against melt down
• Handling of sodium is a major problem

107. What are the advantages of Sodium in fast-breeder reactors?

• Sodium has very low absorption cross-sectional area
• It posses good heat transfer properties at high temperature and low pressure
• It does not react with any of the structural materials used in primary circuits

108. Name the different types of MHD generators

• Open cycle MHD
• Closed cycle MHD
• Closed cycle MHD with liquid metal

109. What is the working principle of magneto hydrodynamic power plant?

The working principle of MHD is as like that of dynamo. Instead of solid conductor high temperature plasma is passed through the magnetic field at sonic speed. When the gas is passed through magnetic field, current is induced. Electrodes collect this induced current.

110. What is the purpose of control rods?

The control rods are used to start the chain reaction, maintain the chain reaction at required level and to shut down the reactor during emergency.

111. What are the different types of load acting on the chimney?

• Its own weight which is considered to act on a single vertical force acting through the centroid
• The wind pressure, which is considered to act on the horizontal force acting on the centroid of vertical projected area.

112. What is meant by Nuclear fission?

Uranium exists in different isotopes of U238, tP34 and U235. Out of these, EP35 is most unstable. When unstable heavy nucleus is bombarded with high-energy neutrons, it splits up roughly into two equal fragments and about 2.5 neutrons are released and a large amount of energy is produced. This process is called nuclear fission.

113. Name the different components of nuclear reactor?

1. Nuclear fuel 2. Moderator 3. Control rods 4. Reflectors
5. Reactor vessel 6. Biological shielding 7. Coolant

114. State some advantages of Pressurized Water reactor?

• The pressurized water reactor is compact
• In this type, water is used as coolant, moderator and reflector water is cheap and available in plenty)
• It requires less number of control rods.

115. What are the advantages of gas cooled reactor nuclear power plant?

1. Fuel processing is simple
2. The use of C02 as coolant completely eliminates the possibility of explosion in reactor.
3. No corrosion problem

116. What is breeding in nuclear reactor?

The process of producing fissionable material from a fertile material such as uranium 238 (U238) and thorium 232 (Th 232 ) by neutron absorption is known as breeding.

117. Name the coolants commonly used for fast breeder reactors?

• Liquid metal (Na (or) Na K)
• Helium (He)
• Carbon dioxide.

118. What is the necessity of Automatic controls for feed water?

The electrical load on power plant varies in an irregular manner. The automatic control provided at a steam power plant successfully meets over the variable load. The automatic control for feed water is necessary sine the supply of feed water depends upon plant load.