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Nuclear Reactors
Nuclear reactors are devices that maintain nuclear reactions. They are used in creating power and elements.
890 Questions
What was the function of graphite in the first atomic reaction?
Graphite was used as a moderator in the first atomic reaction to slow down neutrons released during the fission process. Slowing down the neutrons increases the likelihood of them causing further fission reactions, enabling a self-sustaining chain reaction.
What is the purpose of the graphite rods in a nuclear reactor?
Graphite rods in a nuclear reactor act as moderators, slowing down fast-moving neutrons to speeds at which they are more likely to cause fission in uranium fuel. This helps sustain the chain reaction necessary for power generation.
What type of reaction take place in a nuclear reactor?
Nuclear fission, not to be confused with fusion.
How can the rate of reaction be slowed down in a nuclear fission reactor?
By inserting the control rods which absorb neutrons using boron, cadmium, or other material with a large neutron capture crosssection.
If the reactor should begin to run out of control the SCRAM system will suddenly insert large amounts of neutron absorbing material, instantly stopping the neutron chain reaction.
What is the element found in the control rods of most nuclear reactors?
The element found in the control rods of most nuclear reactors is usually made of a material called boron. Boron is used because it has a high neutron absorption rate, which helps control the nuclear fission process by absorbing excess neutrons and slowing down the reaction.
How can a nuclear powerplant explode?
A nuclear power plant can explode if there is a criticality accident, where an uncontrolled nuclear chain reaction occurs, leading to a sudden release of energy. This could happen due to factors like operator error, equipment failure, or a sudden loss of coolant. However, it's important to note that nuclear power plants are designed with multiple safety systems to prevent such accidents from occurring.
Why are uranium and plutonium used as nuclear fuels?
Because they are the most fissile materials available. Specifically, Uranium-235 (0.7% of natural Uranium), Plutonium-239 (produced in reactors from Uranium-238), and Uranium-233 (produced in reactors from Thorium-232) are the easiest to fission (split) with neutrons, producing enough new neutrons to continue the chain reaction.
Depleted Uranium (Uranium-238) is pretty easy to obtain, you can buy a chunk of it online (although it often sells out fast), whilst Plutonium is not available outside Military and Government controlled facilities.
Most other transuranic elements fission very effectively too, making them good reactor fuels also but they are very radioactive compared to Uranium and Plutonium, making them more dangerous to handle and store.
Why is spent fuel rods stored in a pool of water?
Spent fuel rods are stored in pools of water because they continue to generate heat and radiation after being removed from the reactor. The water acts as a shield to absorb radiation and helps to cool the fuel rods. This method ensures the safe handling and storage of the radioactive material.
Reactor coolant water is kept contained in the primary loop to prevent contamination of the surrounding environment in case of a leak or accident. Mixing it with feed water or allowing it to leave through the cooling tower would increase the risk of radioactive release. Keeping it contained also helps maintain a closed system for efficiency and safety.
What is the range of a nucular explosion?
The range of a nuclear explosion can vary greatly depending on the size of the bomb and the environment in which it detonates. For example, a large nuclear bomb like the Tsar Bomba could have a range of over 50 miles for severe destruction, while smaller bombs may have a more limited range. The blast, heat, and radiation effects of a nuclear explosion can cause damage and casualties over a wide area.
Why heavy water is used in a nuclear reactor?
Heavy water, also known as deuterium oxide, is used in nuclear reactors as a moderator to slow down neutrons to speeds where they are more likely to cause fission in uranium-235. Normal water can also work as a moderator, but heavy water is preferred as it does not absorb neutrons as readily, allowing for more efficient nuclear reactions. Additionally, heavy water is less prone to radioactive activation compared to ordinary water.
This event is commonly known as a "core meltdown" or "nuclear meltdown." It occurs when the fuel rods in the reactor overheat and melt, breaching the containment structures and potentially affecting the surrounding environment with radiation.
What is the original name of nuclear reactor?
The original name of a nuclear reactor is an "atomic pile". The term was first used by Enrico Fermi to describe the experimental setup of the first controlled nuclear chain reaction in Chicago during the Manhattan Project in the 1940s.
What type of nuclear reaction is used in modern day nuclear reactors?
Modern day nuclear reactors primarily use fission reactions, where the nucleus of an atom is split into smaller fragments, releasing large amounts of energy. Fission reactions are controlled in reactors to generate heat, which is used to produce electricity.
What type of nuclear reaction occurs in a reactor?
Nuclear fission is the primary type of nuclear reaction that occurs in a reactor. It involves the splitting of heavy atomic nuclei to release energy.
A moderator is used in nuclear reactor in order to?
The moderator is there to slow down the neutrons produced by fission. These are produced with high energy, that is they move fast, but Uranium235 has a capture cross section much greater for slow neutrons, so they need to be slowed down to make the chain reaction more efficient. Graphite and heavy water are good moderators, and don't absorb too many neutrons, so they can be used even with natural (non-enriched) uranium. Normal water is not so good but it is ok if the uranium is enriched to about 4 percent U235.
The amount of energy released during nuclear fission reactions is primarily determined by the mass difference between the initial nucleus and the fission products. This mass difference is converted into energy according to Einstein's mass-energy equivalence principle (E=mc^2). Additionally, the way in which the fission process is initiated and controlled can also impact the amount of energy released.
Advantages and disadvantages of using uranium as a fuel in nuclear reactors?
There are many advantages. Unlimited power. It is undisputedly cleaner. There is zero pollution after construction. They left hates it! All great reasons to build them.
The disadvantage is the disposal of waste.
The creation of nuclear material is done by concentrating the material from tons of other non radio active material. This material is then used to generate heat, which turns turbines to make power. No radiation is created. None... zip... nada. We concentrate the material to make the issue more intense.
The honest and logical solution would be to take the spent rods that no longer work for reactors and return them from where they came. If we mixed this material with tons of non reactive material in the same ratios and returned it to the same location, what is the net difference? Free power.
Are uranium pellets used in fuel rods that provide the energy for nuclear reactors?
Yes, uranium pellets are indeed used in fuel rods in nuclear reactors. These pellets undergo a process called nuclear fission, where they release energy in the form of heat that is used to generate electricity.
What was used to control the heat of the reactions at Chernobyl?
As in any nuclear reactor control rods made of neutron absorbing material limit the reaction rate. However the control rods of the RBMK type reactor had a serious design error: they were tipped with several feet of graphite, the moderator which made the reaction go faster when first inserted instead of slower. This was compounded by the operators violating procedures and removing the rods completely from the core instead of keeping the graphite tips inside the core at all times.
The temperature is managed by the cooling system (and has nothing to do with the control rods) which in the RBMK uses water. The operators also violated procedures by disabling the emergency cooling system.
Which metals are used in nuclear reactors except thorium?
for example:
- uranium as nuclear fuel
- zirconium for nuclear fuel cladding
- stainless steel for different structures
- cadmium for neutron capture
How many joules does a high grade nuclear reactor give off?
Commercial nuclear reactors operating in the US and around the world come in many different sizes
and generation capacities. As an example, I found the "Quad Cities" power plant in western Illinois,
a couple hundred miles from my home.
The Quad Cities power plant is named for the nearby cities of Davenport, Rock Island, Moline, and
East Moline. It serves all four cities in addition to the western part of Exelon's service area in Illinois.
Quad Cities operates two boiling water reactors, each with a rated maximum capacity of 867 megawatts of
electricity. That's 867 million joules of energy per second out of each one, when it's running wide open
at max capacity.
It's a bit sloppy to speak of energy being "given off" by a nuclear reactor. Any energy "given off" by a
commercial power plant is energy that they can't ship out and sell. And in the case of a nuclear plant,
there are probably a lot of folks living in the neighborhood who would become a mite irritated if any of
that nuclear energy were to come drifting out between the cracks.
The energy generated by the nuclear reactions is kept tightly sealed inside the reactor, and the reactor
is enclosed inside many feet of concrete. The intense heat in the reactor is carried away by another sealed
system of water. The water boils, and runs steam turbine generators, just as if it had been boiled by a coal
or oil fire, instead of by nuclear fission converting mass to energy.
Why lithium use as heat transfer agent in nuclear reactors?
Its not used in any reactor designs. Most use ordinary water. A few designs use molten metals like sodium, NaK (sodium-potassium alloy), mercury, etc. because they do not slow the neutrons as water would and they want fast neutrons in these designs. These metals also transfer heat more efficiently than water does.
Does nuclear energy take place at high temperatures?
Your question expresses a significant bit of conceptual confusion. Perhaps I can clear up some of this confusion and at the same time answer your question.
What we call temperature is simply the manifestation of kinetic energy at the level of the atom (i.e. slow moving atoms = low temperature, fast moving atoms = high temperature). What we call nuclear energy is simply an excess in the nuclear binding energy, which is the energy binding the protons and neutrons together inside the nucleus and is a manifestation of the strong nuclear force and to a lesser extent the weak nuclear force. This movement of atoms has no affect at all on whether there is or is not excess nuclear energy inside atomic nuclei or if that excess nuclear energy is being released or even can be released. Those nuclei having the least nuclear binding energy are the nuclei of the elements from iron through lead, both the elements lighter than iron and the elements heavier than lead have more nuclear binding energy (which can be considered to be excess nuclear binding energy that could potentially be released).
There are three processes that can release excess nuclear energy: radioactive decay, nuclear fission, and nuclear fusion. All of these processes transform nuclear energy to kinetic energy at the level of the atom (i.e. temperature aka heat), and thereby convert a small amount of the mass of the atom into energy. Of these three both radioactive decay and nuclear fission can take place at any temperature, even those so cold as to approach absolute zero. Neither radioactive decay nor nuclear fission takes place any faster or slower with a change in temperature. Nuclear fusion though can only take place at very high temperatures (and pressures) as the nuclei must be very close together and moving fast enough to be able to collide and fuse, despite the strong electrostatic repulsion due to both nuclei involved being positively charged. But this is a threshold temperature, even at high temperatures just below the threshold no nuclear fusion can take place at all and once above the threshold and nuclear fusion begins, raising the temperature further has very little affect on the rate at which that nuclear fusion takes place.
Nuclear reactors operate using the process of nuclear fission and generate heat by both nuclear fission and radioactive decay. We are not yet able to extract nuclear energy in a controlled manner using the process of nuclear fusion (only explosive release of nuclear energy has ever been successfully done using the process of nuclear fusion).
Are control rods of nuclear reactors used to stop a leak?
No, control rods in nuclear reactors are not used to stop leaks. Control rods are used to regulate the power output of the reactor by absorbing neutrons and controlling the rate of nuclear fission. To stop a leak in a nuclear reactor, different containment and safety systems are employed to isolate and contain the leak.
