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A control rod is made of a neutron absorbing material. Boron is common. When the control rod is withdrawn (pulled out) of the reactor, the fission reaction rate increases. When that control rod is inserted, the reaction rate decreases. There are other factors that control the reaction rate, but the rods can be considered as the way to start up or shut down the reactor by pulling or inserting them.
What else can I help you with?
How is the number of neutrons in an assembly involved in creating a sustained nuclear chain reaction?
This answer can not be accurately answered without first knowing what type of nuclear reactor it is. A pressurized-water nuclear reactor is probably the most common so I'll briefly talk about some factors that affect the number of chain reactions in that type of nuclear reactor. First of all, the temperature of the water entering the reactor core will affect the number of chain reactions. The colder the water, the greater the number of reactions. This is primarily because the colder water is more dense and thus releases more neutrons which speeds up the chain reaction rate. Of course, reactor operators, wishing to control the number of chain reactions in order to make the reactor stable may raise or lower "rods" which will be made of a material that tends to absorb neutrons and thus lowering the chain reaction rate. These are the two most common factors affecting chain reaction rate. Would delve further into this question but it gets rather complicated at this point.
What is the function of control rods in a nucleus reactor?
A control rod in a nuclear reactor absorbs neutrons and limits the chain reaction. It is used as a "setpoint" for operation in that it is pulled out a certain amount to allow the chain reaction to heat the reactor. The control rod can also be inserted to absorb neutrons and shut the reactor down.
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.
Do enzymes affect the thermodynamics of a reaction true or false?
False. Enzymes do not affect the thermodynamics of a reaction. They only lower the activation energy required for the reaction to proceed, thereby increasing the rate of the reaction without changing the equilibrium constant or overall energetics of the reaction.
Does sound affect your reaction time?
Yes, sound can affect reaction time. Loud, sudden noises can trigger a startle reflex, causing a momentary delay in reaction time. On the other hand, rhythmic or predictable sounds can help improve reaction time by providing a cue or timing signal.
How is the number of neutrons in an assembly involved in creating a sustained nuclear chain reaction?
This answer can not be accurately answered without first knowing what type of nuclear reactor it is. A pressurized-water nuclear reactor is probably the most common so I'll briefly talk about some factors that affect the number of chain reactions in that type of nuclear reactor. First of all, the temperature of the water entering the reactor core will affect the number of chain reactions. The colder the water, the greater the number of reactions. This is primarily because the colder water is more dense and thus releases more neutrons which speeds up the chain reaction rate. Of course, reactor operators, wishing to control the number of chain reactions in order to make the reactor stable may raise or lower "rods" which will be made of a material that tends to absorb neutrons and thus lowering the chain reaction rate. These are the two most common factors affecting chain reaction rate. Would delve further into this question but it gets rather complicated at this point.
What is the function of control rods in a nucleus reactor?
A control rod in a nuclear reactor absorbs neutrons and limits the chain reaction. It is used as a "setpoint" for operation in that it is pulled out a certain amount to allow the chain reaction to heat the reactor. The control rod can also be inserted to absorb neutrons and shut the reactor down.
How fission is controlled in a nuclear reactor?
All reactors require some form of controllable neutron absorber to accommodate power changes, which cause changes in the concentration of fission product neutron poisons such as Xenon, and to accommodate fuel burn up caused reactivity changes. The reactor must be held at criticality during steady operation and very near it during slow power changes, and moveable control rods are provided for this, usually containing boron which absorbs neutrons strongly. When the reactor is tripped or scrammed the rods drop fully in, and start up requires a slow careful approach to criticality. The following applies to PWR's and is taken from Wikipedia Generally, reactor power can be viewed as following steam (turbine) demand due to the reactivity feedback of the temperature change caused by increased or decreased steam flow. Boron and control rods are used to maintain primary system temperature at the desired point. In order to decrease power, the operator throttles shut turbine inlet valves. This would result in less steam being drawn from the steam generators. This results in the primary loop increasing in temperature. The higher temperature causes the reactor to fission less and decrease in power. The operator could then add boric acid and/or insert control rods to decrease temperature to the desired point. Reactivity adjustment to maintain 100% power as the fuel is burned up in most commercial PWRs is normally achieved by varying the concentration of boric acid dissolved in the primary reactor coolant. Boron readily absorbs neutrons and increasing or decreasing its concentration in the reactor coolant will therefore affect the neutron activity correspondingly. An entire control system involving high pressure pumps (usually called the charging and letdown system) is required to remove water from the high pressure primary loop and re-inject the water back in with differing concentrations of boric acid. The reactor control rods, inserted through the reactor vessel head directly into the fuel bundles, are moved for the following reasons: * To start up the reactor. * To shut down the reactor. * To accommodate short term transients such as changes to load on the turbine. The control rods can also be used: * To compensate for nuclear poison inventory. * To compensate for nuclear fuel depletion. but these effects are more usually accommodated by altering the primary coolant boric acid concentration.
What is hydride gap?
The hydride gap is a concept used in nuclear reactor physics to describe the difference in reactivity worth between hydrogen and deuterium. It refers to the change in reactivity caused by replacing hydrogen with deuterium in the moderator of a reactor. The hydride gap can affect the overall performance and safety margins of a nuclear reactor.
What is the function of baffles in a chemical reactor?
Baffles in a chemical reactor serve to improve mixing and promote uniform distribution of reactants. They help prevent swirling or vortex formation, which can affect the reaction rate and efficiency. Baffles also assist in dissipating heat and enhancing heat transfer within the reactor.
Does nuclear energy stand alone or does it work with other sources?
Nuclear energy from fission is determined by the behaviour of the nucleus and is not affected by external conditions, except in so far as to affect the neutron spectrum and hence the efficiency of a nuclear reactor assembly. A nuclear chain reaction depends only on the enrichment of the nuclear fuel, the lattice arrangement of the fuel, and the moderator, and to a smaller extent the temperature of the moderator, it does not require any other energy input to make it start, because it relies on a small rate of spontaneous fissions in the fuel to provide a small starting neutron flux.
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.
How did the earthquake in Japan affect the people in Canada?
A lot more Canadians than you think live in Japan and there are Canadian deaths and if the nuclear reactor melts down then the radiation may travel here.
Why do chemists need to know the factors that affect reaction rates?
It is important to control chemical reactions in industry.
What is aging effect in electronics?
Aging effect in electronics may affect the electronic instrument and control system of nuclear plants.
Compare and contrast a catalyst and an inhibitor?
Catalysts increase the rate of reaction while Inhibitors decrease it. They both affect the rate of reaction, hence giving us more control over our reaction.
How did nuclear warfare affect the cold war?
How did nuclear warfare affect the cold war?
