Tag: nuclear reactor

Questions Related to nuclear reactor

The amount of $U ^ { 235 }$ in kg which is to be used per hour in a nuclear reactor of capacity $100$ ($E = 200 MeV/fission$)

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. $0.45 \times 10^{-5}$

  2. $4.5 \times 10^{-5}$

  3. $4.5 \times 10^{5}$

  4. $45 \times 10^{-5}$

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Correct Option: B

High energy netrons are used in a nuclear reactor to initiate the fission reaction.

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. True

  2. False

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Correct Option: A
Explanation:
High energy neutrons are used in nuclear reactor to initiate the fission reaction.
For eg- U-235 and U-238

Cadmium rods are used as moderators in a nuclear reactor.

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. True

  2. False

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Correct Option: B
Explanation:
Cadmium rods are used in a nuclear reactor for regulating the power level of the reactor. Cadmium rods are used in nuclear reactors to control the fission rate of radioactive material used. It is capable of absorbing many neutrons without fissioning themselves.
Heavy water, graphite etc. are used as moderator

The material that slows down the neutrons in the nuclear reactor is called

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. Reduced

  2. Compressor

  3. Moderator

  4. None of these

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Correct Option: C

An atomic power nuclear reactor can deliver $300$ MW. The energy released due to fission of each nucleus of uranium atom $U^{235} $ is $170$ MeV. The number of uranium atoms fissioned per hour will be 

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. $4\times 10^{22}$

  2. $30\times 10^{22}$

  3. $10\times 10^{20}$

  4. $5\times 10^{15}$

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Correct Option: C

The fission of one uranium nucleus releases energy of amount x joules. Find the number of fissions required to produced energy at the rate of v MW for t hours a nuclear power plant.

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. $ \dfrac {yt}{x} $

  2. $ \dfrac{x}{yt} $

  3. $ 3.6 \times 10^9 \dfrac {yt}{x} $

  4. $ 3.6 \times 10^9 \dfrac {x}{yt} $

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Correct Option: A

During a nuclear fission reaction 

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. a heavy nucleus breaks into two fragments by itself

  2. a light nucleus bombared by thermal neutrons breaks up

  3. a heavy nucleus bombared by thermal neutrons breaks up

  4. two light nuclei combine to give a heavier nucleus and possibly other products

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Correct Option: C
Explanation:
In nuclear physics and nuclear chemistry, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts, and reaction is triggered by neutron bombardment.

The fissionable material used in a breeder reactor is ________

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. $ _{92}\textrm{U}^{235}$

  2. $ _{94}\textrm{Pu}^{239}$

  3. $ _{90}\textrm{Th}^{234}$

  4. $ _{c}\textrm{C}^{12}$

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Correct Option: B
Explanation:

Non-fissionable uranium-238 is 140 times more abundant than the fissionable U-235 and can be efficiently converted into Pu-239 by the neutrons from a fission chain reaction.

Atomic reactor is based on 

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. controlled chain reaction

  2. uncontrolled chain reaction

  3. nuclear fission

  4. nuclear fusion

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Correct Option: C
Explanation:

All commercial reactor is based on nuclear fission. An atomic reactor means a great explosion of power that results come from a nuclear fission reaction of heavy nuclei (uranium, plutonium). 

The critical mass of $U^{235}$ can be reduced by 

chemistry nuclear physics nuclear reactor the nuclear power station isotopes and nuclear chemistry

  1. putting a neutron reflector around it

  2. heating it

  3. mixing impurity in it

  4. putting neutron absorber around it

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Correct Option: A
Explanation:
Surrounding a spherical critical mass with a neutron reflector further reduces the mass needed for criticality. A common material for a neutron reflector is beryllium metal. This reduces the number of neutrons which escape the fissile material, resulting in increased reactivity.