Pulling the control rods from a nuclear reactor will start it up. Taking them out will cause the reactor to run far too hot and the coolant system will not be able to cool it sufficiently. This may easily result in a meltdown. There are a number of systems that would automatically shut the reactor down if the rods are pulled too far out, by the way.
To slow down the chain reaction in a nuclear reactor, you would insert the control rods. Control rods absorb neutrons and reduce the number available to sustain the chain reaction, thus slowing down the rate of fission reactions occurring in the reactor core.
Temperature control in a nuclear reactor is crucial to prevent overheating, which can lead to a meltdown and release of radioactive materials. Maintaining the right temperature ensures the reactor operates safely and efficiently. Control systems are in place to regulate temperature by adjusting the rate of fission reactions and cooling mechanisms.
It's really just a matter of degree, all reactors produce some power. Those used in a power plant will produce perhaps 3000 to 5000 Megawatts thermal. Low power reactors producing a few kilowatts are used for experiments, teaching in universities, and for producing radioisotopes by irradiating samples, but reactors in this sort of power level would not be harnessed to produce electricity, the heat produced if large enough would be removed and rejected to the atmosphere or to a water cooling circuit. This makes them simple to operate and to start and stop as required.
The radiation from a properly functioning nuclear power reactor is heavily shielded and cannot be approached close enough to be fatal. Radiation from damaged or malfunctioning nuclear power plants can be, and has been, fatal. The nuclear reactor incident at Chernobyl is one example. Nuclear reactor failures aboard ships and submarines also prove fatal but are often hidden behind national security; submarine K-19 'the widowmaker' was one such example. And of course, if one were to get into the reactor room past all of the shielding, any reactor would be fatal.
The reactor itself does not make a lot of sound when operating. Nuclear fission is silent, but moving water in the core (in a pressurized water reactor) might be heard as it circulates. But it would not be easy to put your ear to the reactor vessel as radiation levels would be very high and the vessel would be very hot. Certainly the pumps that are running to circulate coolant will be audible.
If the control rods in a nuclear reactor were somehow to be instantly "jerked" out of the reactor, the reactor would go supercritical. If they were pulled at a normal rate and all of the control rods were pulled out, the reactor would start up and heat up and would end up running far too hot. Any one of several safety systems would shut the reactor down before this could happen. If the safety systems were disabled, the reactor would overheat and a meltdown may occur.
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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.
To slow down the chain reaction in a nuclear reactor, you would insert the control rods. Control rods absorb neutrons and reduce the number available to sustain the chain reaction, thus slowing down the rate of fission reactions occurring in the reactor core.
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Luckily, nuclear rectors are too large to be ran over by a tow truck. However, if one did get ran over by a tow truck, nothing would happen. The containment vessel is enormously strong, and the outer structure is even stronger, so no meltdown would happen.
the nuclear reactor exploded
If you pulled the rods out regardless of the rapid rise in power, the reactor high flux protection safety system would see the rapid rise in power and would scram or trip the rods back in, thus bringing the power down to zero very quickly.
Typically the reaction rate increases.
Highly unlikely if not altogether impossible. In a core meltdown, you might see a steam explosion if the core melts and breaches the containment structure and hits say cooling water. But even a runaway chain reaction in a reactor would not cause a nuclear explosion like a bomb.
This part is the core of the nuclear reactor containing the nuclear fuel.
If a nuclear reactor leaked you would have to evacuate the area around the plant and you would attempt to stop the leak and probably depending on the severeity level of the situation you may need to 'SCRAM' the reactor.