Bissoy.com
Doctors Medicines MCQs Q&A

Heavy water instead of ordinary water is used as a moderator in nuclear reactor because ordinary water

Heavy water instead of ordinary water is used as a moderator in nuclear reactor because ordinary water Correct Answer Absorbs neutrons

CONCEPT:

Nuclear reactor:

  • In a nuclear reactor, the energy is generated by a nuclear fission reaction.
  • In a nuclear reactor, there is a concrete chamber and in this concrete chamber, there is a steel vessel. In this steel vessel, the nuclear fission reaction takes place.
  • Fuel rods: Fuel rods are placed inside the steel chamber.
    • These rods are made of fissionable material. Generally, fuel rods are made of uranium-235, thorium, etc.
  • Moderator: It is used to decrease the speed of fast-moving neutrons.
  • Control rods: These rods are placed between the fuel rods. It is used to control the chain reaction. Control rods are generally made of cadmium.
    • The nuclear reactors are controlled by means of control rods which are made of a strongly neutron-absorbent material such as boron or cadmium (Cd).
  • Coolant: It is used to absorb heat produced during the reaction.

[ alt="F1&F2 U.B Shashi 19 07 2019 D 8" src="//storage.googleapis.com/tb-img/production/19/07/F1%26F2_U.B_Shashi_19_07_2019_D%208.PNG" style="width: 400px; height: 249px;">

EXPLANATION:

  • Moderators are used to slow down the neutrons in order to carry out effective nuclear fission and also absorb neutrons. 
  • The main reason why heavy water is used as the moderator is that it captures less number of neutrons compared to normal water Hence, option 2 is the answer. 

Related Questions

Consider the following statements: 1. The chain reaction process is used in nuclear bombs to release a vast amount of energy, but in nuclear reactors, there is no chain reaction. 2. In a nuclear reactor, the reaction is controlled, while in nuclear bombs, the reaction is uncontrolled. 3. In a nuclear reactor, all operating reactors are ‘critical’, while there is no question of ‘criticality’ in case of a nuclear bomb. 4. Nuclear reactors do not use moderators, while nuclear bombs use them. Which of the above statements about operational principles of a nuclear reactor and a nuclear bomb is / are correct?
Consider the following statements.
1. The chain reaction process is used in nuclear bombs to release a vast amount of energy, but in nuclear reactors, there is no chain reaction.
2. In a nuclear reactor, the reaction is controlled, while in nuclear bombs, the reaction is uncontrolled.
3. In a nuclear reactor, all operating reactors are 'critical', while there is no question of 'critically' in case of a nuclear bomb.
4. Nuclear reactors do not use moderators, while nuclear bombs use them.
Which of the above statements about operational principles of a nuclear reactor and a nuclear bomb is/are correct?
Which of the following statements regarding heavy water are correct? 1. It is extensively used as a moderator in nuclear reactors 2. It cannot be used in an exchange reaction to study the reaction mechanism 3. The viscosity of heavy water is relatively smaller than of ordinary water 4. The dielectric constant of heavy water is smaller than that of ordinary water  Select the correct answer using the code given below: 
Heavy water is used as a moderator in a nuclear reactor. The function of the moderator is
Correct answer for the given blank out of the four alternatives.
The main failings were of conception and a political willingness to settle _________ easy options. _______________ the expansive declarationsof the need "to maintain effective security of all nuclear materials, _______________ includes nuclear materials used in nuclear weapons”, thesummits narrowed their _______________ to civilian holdings __________________ non­nuclear weapon states.
_______________ includes nuclear materials used in nuclear weapons”
Which of the following statement is true? I. In homogeneous reactors the nuclear fuel and the moderator represents a uniform mixture in the fluid form. II. In heterogeneous reactors separate fuel sludge or roads are inserted in the moderator III. Most of the nuclear reactors used these days are of homogeneous type
Which of the following statement/(s) is/are true with regard to "Nuclear Fuel Cycle"? A. It is a series of industrial processes which involve the production of electricity from uranium in nuclear power reactors. B. The nuclear fuel cycles start with the mining of uranium and end with the disposal of nuclear waste. C. To prepare uranium for use in a nuclear reactor, it undergoes the steps of mining, milling, conversion, enrichment, and fuel fabrication. Choose the correct answer from the options given below:
Why is Heavy water used as a moderator in a nuclear reactor?
Consider the following substances: A. Heavy water B. Graphite Which of the substances given above is/are used as a moderator in a nuclear reactor?  Select the code for the correct answer from the options given below:
Among six objects F, G, H, J, K and L :  i. H is twice heavy as K, and J is one and half times as heavy as F.  ii. G is half as heavy as J.  iii. F and J together are less heavy than H.  iv. J and L together are twice as heavy as F.  If the objects are arranged in descending order of their weight, which object will be second from the bottom?