Sage-Tips

Can water be used as a moderator in a nuclear reactor?

It is necessary to slow down the neutrons for efficient operation of a nuclear reactor, a process called moderation. Water is a good moderator, but the hydrogens in the water molecule have a fairly high cross section for neutron capture, removing neutrons from the fission process.

Which is not used as moderator in nuclear reactor?

Heavy water can serve as a neutron moderator in a nuclear reactor, which slows down fast particles and encourages the fission reaction. Light water, Graphite and Heavy water are typically used moderator materials. Boron is not used as a moderator in a nuclear reactor. Hence option 4 is correct.

What substances are used as moderators in a nuclear reactor?

A moderator is a substance used to slow and control the proceeding of the fission process. Moderators include regular (“light”) water, heavy water (where the hydrogen isotope deuterium is used in large quantities), and graphite. Most reactors also require a coolant of some sort, usually water.

Will a reactor that uses ordinary water as the moderator be able to operate using unenriched uranium as a fuel?

Commercial reactors operate with natural uranium or moderately enriched uranium. Using natural uranium as fuel restricts the choice of moderator to graphite and heavy water. This is the case with heavy or ordinary light water, which can be boiling or under pressure.

Which is not used as moderator?

Most commonly used moderator, are graphite and heavy water (D2O). Water cannot be used as moderator in a nuclear reactor.

Which material is not used as moderator?

Most commonly used moderators are graphite and heavy water (D2O) . Water cannot be used as moderator in a nuclear reactor.

What substances are used as a moderator?

Typically-used moderator materials include heavy water, light water, and graphite.

Which of the following is used as a moderator in the reactor of a nuclear power station?

Graphite
The correct answer is Graphite. Heavy water and Graphite both can be used as a moderator in a nuclear reactor. The role of the moderator is to slow down the neutrons emitted in fission in a small number of collisions.

What kind of water is used in nuclear reactor?

All commercial nuclear reactors in the United States are light-water reactors. This means they use normal water as both a coolant and neutron moderator.

Which isotope is used as moderator in nuclear reactors?

B5 isotope is used as moderator in nuclear reactors.

Which of the following is not used in nuclear reactor?

The correct answer is Iron. Iron is not used as a neutron absorbing material in nuclear reactors. The main process in any nuclear reactor for the production of usable energy is a nuclear fission chain reaction.

Which of the following is not used as moderator Mcq answer?

Total energy generated in this fission is E. The bigger part is radioactive, emits five gamma ray photons in the direction opposite to its velocity, and finally comes to rest. Now, answer the following questions: (given ; h = 6. 6×10−34;m=1.

Is heavy water a good moderator for nuclear reactors?

Water is a good moderator, but the hydrogens in the water molecule have a fairly high cross section for neutron capture, removing neutrons from the fission process. Heavy water, used as moderator in Canadian reactors, avoids this loss.

Why is water not a good moderator for neutrons?

In case of the hydrogen (A = 1) as the target nucleus, the incident neutron can be completely stopped – it has the highest average logarithmic energy decrement of all nuclei. On the other hand hydrogen nuclei have relatively higher absorption cross section, therefore water is not the best moderator according to the moderating ratio.

What happens if water coolant is removed from a nuclear reactor?

Loss of the water coolant kills the chain reaction since the fuel configuration is not “critical” without water moderation. Even with the moderator, the fuel is not “critical” without the inclusion of the “delayed” neutrons which may be emitted several minutes after the fission.

Why is water used to slow down nuclear fission reactions?

Neutrons from fission have very high speeds and must be slowed greatly by water “moderation” to maintain the chain reaction. The uranium-235 is enriched to 2.5 – 3.5\% to allow ordinary water to be the moderator. Loss of the water coolant kills the chain reaction since the fuel configuration is not “critical” without water moderation.