Q. Name three important factors in choosing a site for an atomic power plant.
Ans. Three important factors in choosing a site for atomic power plants are:
(i) availability of water supply
(ii) distance from a populated area
(iii) transportation facilities.
Q. Name three different types of fuels used in nuclear reactors.
Ans. Three different types of fuels used in a nuclear reactor are:
(i) natural uranium U-235
(ii) plutonium
(iii) enriched uranium
Q. What is meant by radioactivity?
Ans. The disintegration or decay of unstable atoms accompanied by an emission of radiation is called the radioactivity.
Q. What is decay constant?
Ans. The decay or disintegration constant may be defined as the proportion of atoms of an isotope decaying per second.
Q. What is half-life?
Ans. The half life or half-life period of a radioactive isotope is the time required for one-half of the isotope to decay.
Q. What is meant by mass defect?
Ans. The difference between the experimental mass and calculated mass of the nucleus is called the mass defect or mass deficit.
Q. What is binding energy?
Ans. The energy that binds the nucleus together in the nucleus is called the nuclear binding energy. Binding energy is the energy equivalent of the mass defect.
Q. What is mass energy equivalence?
Ans. 1 amu = 931.5 MeV; where amu stands for atomic mass unit
Q. What is nuclear fission?
Ans. The splitting of a heavy nucleus into two or more smaller nuclei is termed nuclear fission.
Q. What is critical mass?
Ans. The minimum mass of fissionable material required to sustain a chain reaction is called the critical mass.
Q. What is the purpose of a moderator is a nuclear power reactor?
Ans. The purpose of a moderator in a nuclear power reactor is to slow down the neutrons.
Q. Name three moderators commonly used.
Ans. Three commonly used moderators are:
(i) graphite
(ii) ordinary or natural water
(iii) heavy water
Q. What is the purpose of a control rod in a nuclear power reactor?
Ans. Control rods are meant for controlling the rate of fission of U- 235.
Q. Name any two materials used for control rods.
Ans. The materials used for control rods must have very high absorption capacity for neutrons. The commonly used materials for control rod are cadmium, boron or hafnium.
