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Nuclear Reactors
Nuclear reactors are devices that maintain nuclear reactions. They are used in creating power and elements.
890 Questions
How is heat generated inside a nuclear reactor?
Heat is generated inside a nuclear reactor by the release of binding energy (Strong Atomic Force) by the process of fission (splitting one atom into two) or fusion (combining two atoms into one).
How is californium used in nuclear reactors?
We might use californium as a neutron source in a nuclear reactor. Californium is a neutron emitter, and it can be used to "enhance" start-up abilities of a reactor where the fuel isn't as "good" as it might be in a core of, say, highly enriched uranium.
What caused the nuclear reactors to explode?
The nuclear reactors did not explode. The problem was that the cooling system
failed, and they overheated. Some water got so hot that it split into hydrogen
and oxygen, and the hydrogen burned in the oxygen, which cause it to "pop"
What happens to spent fuel rods after they are removed?
they are stored temporarily (for few month) underwater for cooling and partially reducing its radioactivity, then transported to either long term storage (under water or dry storage in casks), or disposal sites, or to reprocessing facilities (to sparate the fuel into uranium, plutonium, and vitrified fission products.
When uranium pellets in a nuclear reactor become overheated, the fuel rods can start to melt, leading to a loss of structural integrity. This can result in a partial or full meltdown of the reactor core, releasing radioactive materials into the environment and potentially causing a nuclear accident like the one that occurred in Chernobyl or Fukushima. Cooling systems must be maintained to prevent overheating.
What will happen if the control rods in a nuclear reactor overheat?
If the control rods in a nuclear reactor overheat, they might deform or even melt, leading to a loss of their ability to regulate the nuclear reaction. This can result in a rapid increase in reactor power and potential overheating of the reactor core, increasing the risk of a meltdown. Cooling systems and emergency protocols are in place to prevent such incidents.
Why is three mile island nuclear plant called three mile island?
The Three Mile Island nuclear plant is named after the island in the Susquehanna River located three miles downstream from the state capital of Pennsylvania, Harrisburg. This is the location of the nuclear power plant that suffered a partial meltdown in 1979.
How long does it take a nuclear reactor rod to cool down?
It can take anywhere from several years to several decades for a nuclear reactor rod to cool down to a level where it can be safely removed from the reactor core and stored. Cooling times vary depending on the type of reactor and the specific isotopes present in the fuel rod.
What is the difference between a fission reactor and a fusion reactor?
In simplest terms, nuclear fission involves splitting atoms apart to make energy. Fusion involves smashing atoms together to make energy. Fusion reactors are currently entirely theoretical and do not exist. The main problem with fusion is figuring out how to get more energy out of the process than you put into making the fusion happen. Right now, the sun is the only place where fusion takes place on any meaningful scale.
Another Answer:
From a power production point of view, i.e. a controlledreaction, it is true that we have not been successful with fusion power. However, from a weapons point of view, i.e. an uncontrolled reaction, we have been successful. This is the basis of the hydrogen bomb. Interestingly, the hydrogen bomb requires so much energy to set it off that we use a fission bomb (the original atomic bomb) to initiate the fusion reaction.
What temperature is nuclear reactor?
This is different in different reactor designs:
- boiling water reactors operate at the boiling temperature of water (100C)
- pressurized water reactors operate at over 300C
- several types of very high temperature gas cooled reactors can operate at temperatures up to 1000C
What is the containment in a nuclear reactor?
It's fairly literal. The nuclear core of a reactor, where the nuclear fuel is, needs to be shielded so that the radiation and any radioactive components inside do not escape into the general environment.
The primary radiation type inside the core is neutron radiation. One of the best shields for neutron radiation is a hydrogen-dense substance, thus pure water is often used. Water, if circulated in a heat sink system, also serves as a heat-removal method (cooling system).
The enclosure for the core and the water pool is a containment vessel made out of something that is airtight and which shields against other kinds of direct radiation. Steel is a common material, perhaps supplemented by concrete and other reinforcement to guard against being damaged by an earthquake, explosion, or an airplane impact (for example).
There is usually an outer containment building that encloses the reactor containment vessel itself. This is a sort of "second line of defense" in case the reactor is breached. Containment buildings are designed to withstand extremely high internal pressures (such as superheated steam) and forces of almost any direction and realistic magnitude. The specific shape of buildings at a nuclear plant are part of their function. The concave towers that are so symbolic of nuclear power are a common design for cooling towers (and not the reactor core itself). Domes are a common shape for reactor containment buildings for a variety of reasons that have mostly to do with encouraging steam condensation.
Another Answer:
The first line of defense is the design of the fuel pin, which contains the fuel, preventing its release into the reactor itself. The pin is made of a zirconium alloy that can withstand extremely high temperature and pressure. These fuel pins are about one half inch in diameter and about 12 feet long, depending on the reactor design. They are organized into bundles, then into assemblies, then into the core complex itself.
The second line of defense is the reactor pressure vessel. Made of high carbon steel with a stainless steel inner liner, it is often about six inches thick. Along with the core cooling system, it forms the primary pressure boundary for the reactor.
The third line of defense is the primary containment. Depending on the reactor design, this is typically a building surrounding the pressure vessel, suppresion pool, and other critical components that is from four to seven feet of hyper structurally reinforced concrete. In the event of a depressurization event of the pressure vessel, the primary containment will hold that release and condense it into the suppression pool.
The fourth line of defense is the secondary containment. Again, depending on the reactor design, this is typically a building around the primary containment and its supporting systems such as the emergency core cooling systems and spent fuel pool, that is around two feet thick.
All of these containment systems are designed to maximize the length of time you have to restore emergency core cooling before you have an uncontrolled release of radiation and/or radioactivity.
There are other lines of defense, but the question only asked about containment.
How long due fuel rods produce heat?
Fuel rods produce heat for a few years while inside a nuclear reactor. After that, they need to be replaced with fresh fuel rods to continue generating heat efficiently.
What would happen to you if living within 10 miles of a nuclear reactor meltdown?
That depends, the three mile island meltdown affected nobody because the containment held everything in and there were no steam or hydrogen explosions. However Chernobyl (no containment, big steam explosion) and Fukushima (containment breached by hydrogen explosions) meltdowns severely contaminated areas well beyond 10 miles distance.
How are spent fuel rods removed from a nuclear reactor?
Spend fuel rods (in the form of fuel bundles) are lifted out of a reactor (which is shut down, of course) and moved over to a holding area. A crane is a good choice for this job. With everything set up, the bundle is hoisted, and swung over a holding area (a holding pool filled with water), and then lowered in. There will be a "rack" of sorts in the pool to support the fuel bundle. Other bundles of spent fuel will be added as they are pulled from the reactor.
What is the purpose of boron in nuclear reactors?
Boron is used inside a nuclear reactor inside a control rod which is used to 'soak' up the neutrons inside the nuclear reactor, a control rod can be used to control the rate of fission inside a nuclear reactor.
How many kilos of uranium in a nuclear reactor?
The amount of uranium in a nuclear reactor depends on its size and design. On average, a typical reactor may contain several tons of uranium fuel in the form of uranium dioxide pellets that are stacked in fuel rods. For example, a 1000-megawatt nuclear reactor may have around 100-150 tons of uranium fuel.
Does the water used to cool a nuclear reactor get contaminated?
In a properly operating nuclear reactor, water used to cool the reactor is not contaminated. This water, called primary coolant, is quite pure. And after shutdown and cooldown, the water has little radiation in it. But if the reactor has some malfunction that overheats the fuel, fuel elements can rupture or melt (a meltdown) and fission products, which are hightly radioactive, can be released into the coolant (the water). The water is then contaminated.
Why can nuclear reactors be dangerous?
Nuclear reactors are dangerous because they emit ionizing radiation that damages the body. Nuclear reactors rely on fission so when the atom splits Uranium or Plutonium emits alpha particles, beta particles, x-rays, and gama rays. The most "dangerous" is gamma rays since they can cross though anything but layers of concrete and/lead
How long does it take a nuclear reactor to cool?
The time it takes to cool a nuclear reactor down varies. If a reactor has been running at nearly full power and is shut down, it takes several days to even weeks to cool it down. The size of the reactor and the "aggressiveness" of a cooling system will affect the cooldown time as well as the power levels at which the reactor was operating at before shutdown.
If a reactor has been operating for some time at high power and is shut down, fission in the core stops (as it does in any shutdown). But fission products in the core are at a high level because the reactor was operating at high power. These fission products will continue to decay for some time. The decaying fission products will be creating a lot of residual heat for this extended period, too.
Why do we have nuclear reactors?
Nuclear reactors are used to generate electricity by harnessing the energy from nuclear fission. This process produces a large amount of energy from a small amount of fuel, making nuclear power a reliable and efficient source of electricity. Additionally, nuclear reactors produce minimal greenhouse gas emissions compared to traditional fossil fuels.
What if a nuclear reactor exploded?
If a nuclear reactor explodes, there can be radiation leakage in the atmosphere which could be dangerous for people. The Fall-out would not only damage the country that it is in but the whole world. The worst part is not the explosion but the Fall-out that comes after. This is really bad because The Radiative Fall-out never Goes away
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 do they start a nuclear reactor?
- With all control rods inserted all the way, begin inserting fuel rods.
- When the basic minimum operating number of fuel rods have been inserted, insert a continuous neutron source of known intensity.
- Measure the neutron flux in the reactor and calculate the reactor's neutron multiplication factor to determine how close you are to design predicted critical.
- Begin withdrawing control rods very slowly, stopping periodically and repeating step 3. Each time the neutron multiplication factor should increase.
- If the multiplication factor keeps increasing in step 4 while the control rods are stopped, you have reached critical. Remove the neutron source and the neutron flux in the reactor should decline slightly then become constant.
- You have now safely started your nuclear reactor. Congratulations!
If anything unexpected happens reinsert all control rods, remove the neutron source, find and fix the problem, and restart the procedure.
Is a control rod in nuclear reactor a hollow tube?
Varies.
A hollow control rod can act as a "neutron trap."
The moderator in the hollow center helps slow the fast neutrons into the thermal region for increased absorption by the surrounding absorbing material such as Boron.
How much plutonium is needed to run a reactor?
The amount of plutonium needed to run a reactor depends on the specific reactor design and size. Typically, a few kilograms to several hundred kilograms of plutonium may be required for a nuclear reactor. The concentration and purity of the plutonium play a significant role in determining the exact amount needed.
