Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q61 (CDS-I/2009) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Atomic and nuclear physics Answer Verified

Which one of the following is heavy water used in nuclear reactor ?

Result
Your answer: —  Â·  Correct: B
Explanation

Heavy water, chemically known as deuterium oxide (D2O), is a form of water where the common hydrogen atoms (protium) are replaced by deuterium isotopes [t1][t5]. While ordinary water (H2O) has a molecular weight of approximately 18 amu (2x1 for hydrogen + 16 for oxygen), heavy water has a molecular weight of approximately 20 amu [t4][t6]. This is because deuterium contains one proton and one neutron, giving it an atomic mass of approximately 2, leading to a total molecular mass of 20.03 amu for D2O [t4][t7]. In nuclear reactors, specifically Pressurized Heavy Water Reactors (PHWRs), heavy water is used as an efficient moderator to slow down fast-moving neutrons to facilitate the fission of uranium atoms [t1][t2]. It also serves as a coolant due to its stable nuclear properties [t2].

Sources

  1. [2] https://hwb.gov.in/frequently-asked-questions-faqs
  2. [3] https://www.britannica.com/science/heavy-water
  3. [4] https://webbook.nist.gov/cgi/cbook.cgi?ID=C7789200
How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
50%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

NDA-II · 2015 · Q45 Relevance score: 4.47

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 exchange reaction to study reaction mechanism 3. Viscosity of heavy water is relatively smaller than that 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:

CAPF · 2015 · Q120 Relevance score: 4.40

Heavy water of an atomic reactor is :

CAPF · 2010 · Q72 Relevance score: 3.26

Statement I : Heavy water is used as moderator in nuclear reactor. Statement I : Thermal neutrons are used for fission reaction in a reactor.