In the Canada Deuterium Uranium (CANDU) reactor, a natural uranium fuelled reactor, the function of moderator and coolant is performed by:
- A.heavy water
- B.light water
- C.carbon dioxide
- D.sodium
Correct answer
Explanation
The correct answer is A, heavy water. The CANDU design, from which India's pressurised heavy water reactors descend, burns natural uranium, and natural uranium contains only about seven parts in a thousand of the fissile isotope uranium 235. Such a lean fuel can sustain a chain reaction only if very few neutrons are wasted, and heavy water absorbs far fewer neutrons than ordinary water while still slowing them down, so it serves as both moderator and coolant. Option B is wrong because light water absorbs too many neutrons, which is why reactors that use it must be fuelled with enriched uranium. Option C is wrong because carbon dioxide is used as a coolant in gas cooled reactors, where graphite is the moderator. Option D is wrong because liquid sodium is the coolant of a fast breeder reactor, which deliberately has no moderator at all.
Read the full article: Nuclear Programme of India: Three Stages and Reactors
Practice Questions
View allWhere was India's first nuclear power plant set up?
- A.Tarapur
- B.Kudankulam
- C.Kaiga
- D.Rawatbhata
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The Tarapur Atomic Power Station in Maharashtra was commissioned in 1969 with American assistance and was the first nuclear power station in India as well as in Asia; its first two units are boiling water reactors, a design used nowhere else in the country.
Read the full explanation →The coolant used in a boiling water reactor is:
- A.carbon dioxide
- B.pressurised water
- C.a mixture of water and steam
- D.liquid metal
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In a boiling water reactor, the design used at Tarapur, ordinary water is allowed to boil inside the reactor vessel itself, so the coolant leaving the core is a mixture of water and steam; the steam is separated at the top and driven straight to the turbine, without the separate…
Read the full explanation →Who is regarded as the father of the Indian nuclear programme?
- A.Vikram Sarabhai
- B.Homi Jehangir Bhabha
- C.Raja Ramanna
- D.A. P. J. Abdul Kalam
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Bhabha founded the Tata Institute of Fundamental Research in 1945, became the first chairman of the Atomic Energy Commission in 1948, drew up the three stage plan built around India's thorium, and led the establishment at Trombay that was renamed the Bhabha Atomic Research Centre after his death in 1966.
Read the full explanation →Apsara, the first nuclear research reactor in Asia, became critical in 1956 at which place?
- A.Kalpakkam
- B.Trombay
- C.Rawatbhata
- D.Tarapur
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Apsara went critical at Trombay near Mumbai on 4 August 1956 and was the first nuclear research reactor not only in India but in the whole of Asia; the CIRUS reactor of 1960 and the Dhruva reactor of 1985 were built at the same site, which is today the Bhabha…
Read the full explanation →The second stage of India's three stage nuclear programme is based on which type of reactor?
- A.Pressurised heavy water reactors
- B.Fast breeder reactors
- C.Boiling water reactors
- D.Gas cooled reactors
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The second stage uses the plutonium 239 recovered from the spent fuel of the first stage as the fuel of a fast breeder reactor, with a blanket of thorium around the core that is converted into uranium 233; a breeder produces more fissile material than it burns, which is how…
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