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The advantage of heavy water as coolant over light water in pressurized reactors?
In the CANDU reactor heavy water is used as the moderator. It is a much better moderator than light water because it does not absorb neutrons so strongly, and enables non-enriched uranium to be used. The heavy water moderator is enclosed in a tank with fuel channel tubes, called technically a calandria. The coolant is also heavy water which flows through the tubes and hence past the fuel elements, and then transfers its heat to a light water secondary circuit. In a PWR or BWR light water is used both as moderator and coolant, which is obviously much cheaper and less complicated, but does require uranium enriched in U-235.
How is fuel in a nuclear reactor obtained?
It is either mined or synthesized, though usually mined, as this is much less expensive. Some reactors (such as the CANDU) can even use the waste from other reactors, without any refinement at all.
Heavy water is preferred as a moderator over normal water?
Heavy water has the advantage of being a good moderator and of absorbing fewer neutrons than does light water, so that natural (unenriched) uranium can be used. Light water demands enriched uranium, around 4 to 5 percent U-235. So you can make a choice: use heavy water which is expensive to produce, or use light water and expensive enriched uranium. You can see the different approach between the US and Canada. In the US there was experience of enrichment from the WW2 Manhattan project, in Canada there was no such experience but they had cheap hydro power to use to produce heavy water, so developed the Candu type of reactor.
Why is heavy water used for heat transfer in nuclear reactor?
Heavy water has the same heat transfer properties as ordinary water, at least in practical terms. It is used in some reactors as the moderator since it is much more efficient at slowing fast neutrons than ordinary water, thus enabling unenriched uranium to be used as the fuel. It is not used to transfer heat to the power producing part of the plant, only as a static tank (called a calandria) full of heavy water as moderator. (See CANDU)
How does a heavy water nuclear reactor work?
Uranium and Plutonium atoms require nuetrons moving at a certain speed, with a certain amount of kenetic force, to fission properly and often, and to achieve this speed, a neutron moderator is placed between the neutron source and the fuel, which slows the neutrons down by causing them to hit its molecules. Water is often used, since the energy transfer is much more efficient, as hydrogen atoms are almost identical in size to neutrons, possesing only one proton (like two billiard balls striking each other), but hydrogen atoms sometimes absorb neutrons, meaning less get through to cause fissions, and once the concentration of fissionable material drops blow a certain percentage (usualy somewhere around 5%) fission is no longer maintainable. Heavy water posses hydrogen atoms with one extra neutron, so althought the energy transfer is slightly less efficient than with hydrogen atoms, there is much less chance of the atoms abosorbing neutrons, and so many more neutrons get through, allowing the reactor to run on fuel with much lower concetrations of fisionable material (even as low as 0.7%, the natural level of U-235 in Uranium ore). Thus somereacotrs using heavy warer as a neutron moderator (such as the CANDU) can even run on the waste from other, "light water moderated" reactors (light water is just another name for normal water, as opposed to heavy water).
The advantage of heavy water as coolant over light water in pressurized reactors?
In the CANDU reactor heavy water is used as the moderator. It is a much better moderator than light water because it does not absorb neutrons so strongly, and enables non-enriched uranium to be used. The heavy water moderator is enclosed in a tank with fuel channel tubes, called technically a calandria. The coolant is also heavy water which flows through the tubes and hence past the fuel elements, and then transfers its heat to a light water secondary circuit. In a PWR or BWR light water is used both as moderator and coolant, which is obviously much cheaper and less complicated, but does require uranium enriched in U-235.
Why Pressurized Water Reactor nuclear reactor is the most commonly used reactor?
I guess because it is the one with the fewest operational problems and the longest operational life. BWR's introduce the problems of a contaminated turbine. Gas cooled graphite reactors are efficient but there are life limitations on the graphite. Heavy water reactors have the benefit of using natural uranium but the heavy water is very expensive to produce. So the choice is between enriching uranium as for the PWR, or producing heavy water as for the CANDU. Most countries are now opting the PWR way as enriching uranium by centrifuge has become much less expensive than the old gaseous diffusion method.
How is fuel in a nuclear reactor obtained?
It is either mined or synthesized, though usually mined, as this is much less expensive. Some reactors (such as the CANDU) can even use the waste from other reactors, without any refinement at all.
How much uranium 235 is used in a nuclear reactor?
The amount of uranium-235 used in a nuclear reactor depends on the design and size of the reactor. Typically, a reactor core contains several tons of uranium fuel, with the concentration of uranium-235 ranging from 3-5%. The fuel is arranged in fuel assemblies to sustain a controlled nuclear fission chain reaction.
Heavy water is preferred as a moderator over normal water?
Heavy water has the advantage of being a good moderator and of absorbing fewer neutrons than does light water, so that natural (unenriched) uranium can be used. Light water demands enriched uranium, around 4 to 5 percent U-235. So you can make a choice: use heavy water which is expensive to produce, or use light water and expensive enriched uranium. You can see the different approach between the US and Canada. In the US there was experience of enrichment from the WW2 Manhattan project, in Canada there was no such experience but they had cheap hydro power to use to produce heavy water, so developed the Candu type of reactor.
Why is heavy water used for heat transfer in nuclear reactor?
Heavy water has the same heat transfer properties as ordinary water, at least in practical terms. It is used in some reactors as the moderator since it is much more efficient at slowing fast neutrons than ordinary water, thus enabling unenriched uranium to be used as the fuel. It is not used to transfer heat to the power producing part of the plant, only as a static tank (called a calandria) full of heavy water as moderator. (See CANDU)
What are two types of reactors used in the US?
Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs) are two types of reactors commonly used in the US for generating nuclear power. PWRs use pressurized water to transfer heat, while BWRs use boiling water to produce steam for electricity generation.
How does a heavy water nuclear reactor work?
Uranium and Plutonium atoms require nuetrons moving at a certain speed, with a certain amount of kenetic force, to fission properly and often, and to achieve this speed, a neutron moderator is placed between the neutron source and the fuel, which slows the neutrons down by causing them to hit its molecules. Water is often used, since the energy transfer is much more efficient, as hydrogen atoms are almost identical in size to neutrons, possesing only one proton (like two billiard balls striking each other), but hydrogen atoms sometimes absorb neutrons, meaning less get through to cause fissions, and once the concentration of fissionable material drops blow a certain percentage (usualy somewhere around 5%) fission is no longer maintainable. Heavy water posses hydrogen atoms with one extra neutron, so althought the energy transfer is slightly less efficient than with hydrogen atoms, there is much less chance of the atoms abosorbing neutrons, and so many more neutrons get through, allowing the reactor to run on fuel with much lower concetrations of fisionable material (even as low as 0.7%, the natural level of U-235 in Uranium ore). Thus somereacotrs using heavy warer as a neutron moderator (such as the CANDU) can even run on the waste from other, "light water moderated" reactors (light water is just another name for normal water, as opposed to heavy water).
How much coolant is used in a nuclear power reactor?
The amount of coolant used in a nuclear power reactor can vary depending on the design of the reactor. Generally, a nuclear power reactor may use thousands to millions of gallons of water or a different coolant material to remove heat generated during the nuclear fission process. The coolant circulates through the reactor core to transfer heat and help regulate the temperature of the reactor.
How much energy is lost during nuclear power producttion?
The efficiency of a PWR or BWR reactor power plant is about 33 percent, so this means that about 67 percent of the reactor's thermal output is rejected to the cooling water
How much deuterium is in one litter of heavy water?
One liter of heavy water contains approximately 11 grams of deuterium.
How much did the Chernobyl reactor lid weigh when it was in place?
The Chernobyl reactor lid weighed about 1,000 tons when it was in place.
