What are the functions of the moderator and the coolant in a nuclear fission reactor?
Inside the reactor vessel, the fuel rods are immersed in water which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods can then be inserted into the reactor core to reduce the reaction rate or withdrawn to increase it.
What are two problems with liquid sodium cooled reactors?
Disadvantages. A disadvantage of sodium is its chemical reactivity, which requires special precautions to prevent and suppress fires. If sodium comes into contact with water it reacts to produce sodium hydroxide and hydrogen, and the hydrogen burns in contact with air.
What is one advantage of a pressurized water reactor?
[1] One major advantage of this reactor is that it is easy to operate because less power is being produced as the heat increases. [3] In addition, the core of the reactor contains less fissile material, decreasing the chances of additional fission events to occur, making the reactor safer and more controllable.
What would be the disadvantage to using fusion to produce electricity?
But fusion reactors have other serious problems that also afflict today’s fission reactors, including neutron radiation damage and radioactive waste, potential tritium release, the burden on coolant resources, outsize operating costs, and increased risks of nuclear weapons proliferation.
Why is water a better moderator than carbon?
Water and carbon (graphite) are commonly used moderators. 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.
What are the properties of carbon dioxide as a coolant?
The most important property of carbon dioxide as a coolant is that, when expanded to the atmosphere, a portion of the liquid becomes gas, while the consequent cooling, due to the absorption of the latent heat of vaporization, converts a further portion of the liquid to solid CO 2 in the form of ‘snow’.
Can I use liquid carbon dioxide as a cutting coolant?
ATTEMPTS have been made in the past to use liquid carbon dioxide as a cutting coolant, notably in the U.S.A. However, results were not in general very satisfactory, and this may have been because the material was applied by people who were more familiar with machine tools than with carbon dioxide.
What are the disadvantages of carbon dioxide?
What are the disadvantages of carbon dioxide? Carbon dioxide gas can be toxic and very harmful to humans, It increases the temperature of the Earth’s atmosphere, It causes the global warming effect that has bad effects on the Earth.
What materials can be used as coolant in nuclear reactors?
Some other materials (like NaK, Lead) can also be used as coolant in nuclear reactors and some are under research. Water in light water reactors. But you need enriched Uranium to fuel such reactors, If you want to use natural uranium as fuel, your have to use heavy water as coolant.