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If the control rods in a nuclear reactor are removed would the condition be supercritical or subcritical?
Wiki User
∙ 13y ago
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.
Wiki User
∙ 13y ago
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What is meant by supercritical and how does it relate to making a nuclear bomb?
A subcritical mass cannot sustain a nuclear chain reaction, it dies exponentiallyA critical mass can sustain a nuclear chain reaction, but it remains constant neither increasing nor decreasingA supercritical mass not only sustains a nuclear chain reaction but it increases exponentially until the mass explodesA nuclear fission bomb must become supercritical at some time in order to explode.
What is meant by supercritical andhow dose it relate to making a nuclear bomb?
subcritical - a mass or arrangement of fissionable or fissile material unable to sustain a neutron chain reaction. It can provide a fixed amount of neutron multiplication from a neutron source, but after removal of the neutron source the chain reaction rate drops exponentially.critical - a mass or arrangement of fissionable or fissile material capable of sustaining a constant neutron chain reaction. No increase or decrease. (Nuclear reactors operate at critical)supercritical - a mass or arrangement of fissionable or fissile material capable of not only sustaining a neutron chain reaction, but once initiated the chain reaction rate rises exponentially. (Nuclear fission bombs explode when made supercritical)A nuclear fission bomb must have 2 of these states: subcritical (so that it can't explode until desired) and supercritical (so that it explodes with an effective yield). This requires a rapid "assembly" system using conventional explosives to rearrange the fissile material from subcritical to supercritical in about 1ms. A neutron source starts the chain reaction and the explosion completes in about 1 microsecond.
Can a nuclear power plant turn into a atomic bomb?
No, a reactor is operated at critical and a bomb at supercritical. Also reactors include safety shutdown systems that quickly make them subcritical stopping the reaction.However reactors can have steam explosions and hydrogen/oxygen explosions. These are physical and chemical explosions respectively, not nuclear.
What are some of the things in nuclear weapons?
The subcritical masses of fissile material are in there, obviously. And there will be the conventional chemical explosives that drive the fissile material together and hold it there for a split second. The triggering mechanism is included with the sensor and control package. Some shielding and reflectors will be in there, and so will some materials that "lock out" the subcritical masses to prevent them "engaging" in the event of an accident. There are a few "security" features within the case of the weapon as well. As security concerns color all aspects of nuclear weapon design and construction, we can only speak to this subject matter in general terms.
What is a dangerous condition caused by overheating inside a nuclear reactor?
The dangerous condition that can occur in a nuclear reactor and due to overheating is a nuclear meltdown.
What is the difference in nuclear power plants and a nuclear bomb.?
A nuclear power plant is a controlled nuclear pile. Both slow and fast reactors contain radioactive material (uranium or plutonium), and are kept from going supercritical due to moderator (cadmium control rods) and coolant such as sodium or, most commonly, water. Thus, the rate of nuclear reaction can be controlled. However, in a nuclear bomb, the goal is (super)criticality. Two subcritical masses are brought together to form a critical/supercritical mass, or a subcritical mass is brought to criticality by implosion, increasing the density, and no control of the reaction is provided. In this way, a nuclear bomb is allowed to reach critical mass and result in runaway nuclear reaction very quickly...or order to result in nuclear detonation.
What is meant by supercritical and how does it relate to making a nuclear bomb?
A subcritical mass cannot sustain a nuclear chain reaction, it dies exponentiallyA critical mass can sustain a nuclear chain reaction, but it remains constant neither increasing nor decreasingA supercritical mass not only sustains a nuclear chain reaction but it increases exponentially until the mass explodesA nuclear fission bomb must become supercritical at some time in order to explode.
What happens when the mass of fissile material used in nuclear weapons is subcritical?
Nothing, it has to become supercritical for a nuclear detonation to happen. Most bombs perform this transition from subcritical state to supercritical state by an implosion driven by conventional explosive lenses. Once supercritical a neutron source is fired through the fissile material to start the reaction leading to the nuclear detonation.There is a special type of test detonation called a hydronuclear test where the amount of fissile material remains subcritical throughout the implosion. When the neutron source fires the reaction simply multiplies the number of neutrons by a factor then dies out. No nuclear detonation happens. Measurements of this neutron flux can tell about the quality of the implosion, safety, etc. But as there is no nuclear yield, several of the nuclear test ban treaties allowed these hydronuclear tests while banning tests with nuclear yields.
What is meant by supercritical andhow dose it relate to making a nuclear bomb?
subcritical - a mass or arrangement of fissionable or fissile material unable to sustain a neutron chain reaction. It can provide a fixed amount of neutron multiplication from a neutron source, but after removal of the neutron source the chain reaction rate drops exponentially.critical - a mass or arrangement of fissionable or fissile material capable of sustaining a constant neutron chain reaction. No increase or decrease. (Nuclear reactors operate at critical)supercritical - a mass or arrangement of fissionable or fissile material capable of not only sustaining a neutron chain reaction, but once initiated the chain reaction rate rises exponentially. (Nuclear fission bombs explode when made supercritical)A nuclear fission bomb must have 2 of these states: subcritical (so that it can't explode until desired) and supercritical (so that it explodes with an effective yield). This requires a rapid "assembly" system using conventional explosives to rearrange the fissile material from subcritical to supercritical in about 1ms. A neutron source starts the chain reaction and the explosion completes in about 1 microsecond.
Can a nuclear power plant turn into a atomic bomb?
No, a reactor is operated at critical and a bomb at supercritical. Also reactors include safety shutdown systems that quickly make them subcritical stopping the reaction.However reactors can have steam explosions and hydrogen/oxygen explosions. These are physical and chemical explosions respectively, not nuclear.
What is used as an explosive ingredient in nuclear weapons?
There are 3 types of explosives used in nuclear weapons:conventional explosives, to rapidly assemble a subcritical mass into a supercritical mass of fissile material; many different explosives can and have been used.fissile material; highly enriched Uranium-235 and/or Plutonium-239.fusion fuel; Deuterium, Tritium, and/or Lithium Deuteride.
When do a nuclear reactor become critical or subcritical?
Critical is that point when the population of fission events is neither growing nor decreasing, and that it is sustained by its own means. In this state, on a large scale statistical basis, exactly one neutron produces one fission, which goes one to produce one neutron, which goes on to produce one fission, and so on and so forth. Subcritical is the state where that population is decreasing, and supercritical is where that population is increasing. Criticality is also related to power output, as the number of fission events is directly tied to energy or power output. When you ramp a nuclear reactor up in power, you go slightly supercritical while you increase the population, and therefore the energy output, but once you achieve your target power, you let your moderator step in and modulate the power in a self-modulating cycle. Similarly, as you trim power down, you go slightly subcritical while you decrease the population, and then you let the moderator kick back in, that is, unless you lose control and you initiate a trip/scram, taking the reactor to shutdown, which is way-way-subcritical.
How do you get nuclear weapons atomic bombs from nuclear fission?
fission is the nuclear reaction that makes both bombs and reactors possible.if a mass of fissile material is subcritical, its neutron multiplication factor is less than 1 and any chain reaction started in it will die out with only a small release of heat and radiation.if a mass of fissile material is exactly critical, its neutron multiplication factor is exactly 1 and a chain reaction started in it will be sustained at a constant rate. this can be used as a nuclear reactor.if a mass of fissile material is supercritical, its neutron multiplication factor is greater than 1 and a chain reaction started in it will accelerate out of control until it either melts (a fizzle) or explodes (a detonation). this can be used as a bomb.to make a nuclear bomb you also need 2 other things:a rapid assembly system using chemical explosives to convert a subcritical mass to a supercritical mass fast enough to prevent a fizzle caused by either stray neutrons or spontaneous fission.a neutron source to fire neutrons into the resulting supercritical mass at the optimal time to get an explosion of the desired yield. advancing or retarding the firing of the neutron source will reduce yield from the maximum possible with a given design.
How are atomic bombs made?
Much of the design particulars are top secret-Q but basically you need a mass of fissile material (usually plutonium) large enough to be able to reach supercritical mass and support an uncontrolled nuclear reaction. The explosion is triggered by compressing the plutonium by an implosion to assemble the initially subcritical mass into a supercritical mass rapidly (a couple milliseconds). once the material reaches supercritical mass, a neutron source is fired through it to start the reaction at the optimal time. about 4µs to 7µs later the bomb explodes. The longer the design is able to hold the bomb together, the higher the yield when it does disassemble.
What are the materials needed to make a nuclear weapons?
At a minimum:Fissile material to provide the energyConventional explosives to rapidly assemble (about 1ms to 10ms) the fissile material from subcritical to supercritical formA tamper made of dense metal to contain the reaction for about 1µs to get good yieldneutron sources to start the fission at optimal supercriticalityTo make a practical bomb additional materials and systems would be required.
What can cause a nuclear power plant blow up?
A steam explosion from flash evaporation of coolant water. This is what blew up Chernobyl.A chemical hydrogen/oxygen gas explosion caused by build up of hydrogen gas in the plant when water decomposes on contact with overheated zirconium fuel rod cladding.A nuclear explosion in a nuclear reactor is not possible, the fuel cannot be assembled into a supercritical mass configuration fast enough (~1ms) as this would require explosives. If the reactor core did suddenly go slightly supercritical, the energy release would simply cause a brief partial meltdown, restoring the material to a subcritical configuration. This could trigger a steam explosion that ejected parts of the reactor core (as happened at Chernobyl) but no nuclear yield would occur.
Is a nuclear capable of exploding as a nuclear bomb?
A Nuclear power plant is not under any circumstances of detonating like a nuclear weapon. To understand this, you must understand the basics behind a nuclear weapon, in which an explosive primer is used to kickstart a runaway fission reaction that produces the famous explosive effects of a nuclear weapon. this runaway fission effect is not very easy to reproduce, and one of the great obstacles of the Manhattan project was actually figuring out just how to create this effect. In short, to create a nuclear detonation, one cannot simply have it on accident, it must be created purposefully.Minor clarification, in a nuclear fission weapon the fissile material is initially in a very subcritical configuration (where it cannot support a sustained neutron chain reaction), chemical explosives are used to rapidly assemble (in about 1ms) the fissile material into a very supercritical configuration (where any neutron chain reaction increases uncontrollably at an exponential rate), then a pulsed neutron source fires through the supercritical mass of fissile material setting it off.A nuclear power plant operates at exactly critical (the neutron chain reaction in the fissionable material stays constant). It is not possible for a nuclear power plant's reactor to go far enough supercritical fast enough to have a nuclear explosion, it would "fizzle" first by having a meltdown reducing itself back to a subcritical configuration.That being said, nuclear power plants can explode, but only steam explosions, and hydrogen gas explosions(rapid combustion of hydrogen-oxygen mixtures). Chernobyl was a steam explosion, the reactors in Japan could have had either or both.
