History Main / GoingCritical

* In both RealLife and ''Series/{{Chernobyl}},'' the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go ''super''critical for a breif instant (graphite is a neutron ''accelerator''), melting the coolant system and causing the coolant (water) to spill onto the hell-hot fuel rods, resulting in a blast of superheated steam that ripped the roof off of the reactor vessel and resulted in a meltdown. Nuclear scientist Legasov is, however, concerned that if the mixture of melting fuel, powdered boron (meant to poison[[labelnote:*]]yes, that's the technical term[[/labelnote]] the reaction), and sand (meant to smother the flames) hits the coolant reservoir, the resultant explosion will be about 30 megatons, which is more in line with this trope. A good-sized glob of this "lava" (known as corium) would cause another steam explosion that would sure as hell make things worse, but it wouldn't go up like a nuke [[DiabolusExMachina unless all of it was dropped into the reservoir at once (and then in a wide pattern that would maximize flash-heating).]]

* In both RealLife and ''Series/{{Chernobyl}},'' the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go ''super''critical for a breif instant (graphite is a neutron ''accelerator''), melting the coolant system and causing the coolant (water) to spill onto the hell-hot fuel rods, resulting in a blast of superheated steam that ripped the roof off of the reactor vessel and resulted in a meltdown. Nuclear scientist Legasov is, however, concerned that if the mixture of melting fuel, powdered boron (meant to poison[[labelnote:*]]yes, that's the technical term[[/labelnote]] the reaction), and sand (meant to smother the flames) hits the coolant reservoir, the resultant explosion will be about 30 megatons, which is more in line with this trope. A good-sized glob of this "lava" (known as corium) would cause another steam explosion that would sure as hell make things worse, but it wouldn't go up like a nuke unless all of it was [[DiablousExMachina dropped into the reservoir at once (and then in a wide pattern that would maximize flash-heating).]]

* In both RealLife and ''Series/{{Chernobyl}},'' the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go ''super''critical for a breif instant (graphite is a neutron ''accelerator''), melting the coolant system and causing the coolant (water) to spill onto the hell-hot fuel rods, resulting in a blast of superheated steam that ripped the roof off of the reactor vessel and resulted in a meltdown. Nuclear scientist Legasov is, however, concerned that if the mixture of melting fuel, powdered boron (meant to poison[[labelnote:*]]yes, that's the technical term[[/labelnote]] the reaction), and sand (meant to smother the flames) hits the coolant reservoir, the resultant explosion will be about 30 megatons.

* In both RealLife and ''Series/{{Chernobyl}},'' the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go ''super''critical for a breif instant (graphite is a neutron ''accelerator''), melting the coolant system and causing the coolant (water) to spill onto the hell-hot fuel rods, resulting in a blast of superheated steam that ripped the roof off of the reactor vessel and resulted in a meltdown. Nuclear scientist Legasov is, however, concerned that if the mixture of melting fuel, powdered boron (meant to poison [[note:*:yes, that's the technical term]] the reaction), and sand (meant to smother the flames) hits the coolant reservoir, the resultant explosion will be about 30 megatons.

* In both RealLife and ''Series/{{Chernobyl}},'' the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go ''super''critical for a breif instant (graphite is a neutron ''accelerator''), melting the coolant system and causing the coolant (water) to spill onto the hell-hot fuel rods, resulting in a blast of superheated steam that ripped the roof off of the reactor vessel and resultibg in a meltdown. Nuclear scientist Legasov is, however, concerned that if the melting fuel (known as corium) hits the coolant reservoir, the resultant explosion will be about 30 megatons.

A subtrope of SrtisticLicenseNuclearPhysics. See also ContainmentField. When a reactor "goes critical" but is then turned off with no consequences, it's InstantCooldown.

See also ContainmentField. When a reactor "goes critical" but is then turned off with no consequences, it's InstantCooldown.

In fiction, the word "reactor" seems to mean [[SmallReferencePools exclusively nuclear reactions]], despite the word being common enough in chemistry since "reactor" simply means where a reaction happens. Another contrast between fiction and reality occurs with the term "critical". Fiction uses the word to say "it's going to explode!", whereas real nuclear physics use it to say "the reaction sustains itself", so a reactor is critical if it's ''on''. Relatedly, "supercritical" simply means the reaction is increasing in power, and a surge of power causes "prompt critical", which means the reaction is critical solely from the "prompt" neutrons created by fission events, which means an explosion is immanent.[[note]]Since a neutron in flight cannot be controlled by processes working at human time scales, reactors are designed to be critical with the "delayed" neutrons released by subsequent isotope decay. This may have happened only once, in the [[http://en.wikipedia.org/wiki/Sl-1 SL-1 reactor accident]].[[/note]] (Designed bombs, on the other hand, go "[[UpToEleven prompt supercritical]]".) Also incorrect is "meltdown", meaning an explosion suspiciously similar to that of an atom bomb, or at least large enough to [[MadeOfExplodium blow the vehicle/facility in question to pieces]]. In real nuclear physics, meltdowns are just that - the fissile core ''melts'' into slag, hot enough to flash coolant into steam (wherein you get the associated bang) and possibly melt through the reactor vessel.

* In the Film/JamesBond movie ''Film/TheWorldIsNotEnough'', TheDragon Renard attempts to turn the reactor in a nuclear sub critical by inserting a rod of weapons grade plutonium. In the bare reactor. With nothing more than a shirt protecting him from hard radiation. Granted, he wasn't expecting to survive the act, but Bond is there with him. This might be slightly forgivable given that the intent was to contaminate the whole area, not necessarily blow it to hell. Of course, nobody except Dr. Jones actually understands how inserting the weapons grade plutonium into the reactor would cause an 'instant, catastrophic meltdown'.
* ''Film/TheSwarm'' had a bunch of killer bees turn a nuclear power plant into a nuclear bomb in less than a minute, somehow.
* At the end of ''Film/ResidentEvilApocalypse'', Raccoon City in its entirety was destroyed by a tactical nuclear missile in an attempt to wipe out the T-virus outbreak. Later on, there are news broadcasts shown with evidence recorded by the protagonists discredited. One reporter even made the statement that a nearby nuclear reactor exploded by "going critical."

* The ''{{Franchise/Alien}}'' franchise has done this twice - first with the reactor of the ''Nostromo'' in ''{{Film/Alien}}'', and then with the reactor of the atmosphere processor in ''{{Film/Aliens}}''. In the first example, this is because Ripley turns on the SelfDestructMechanism on the ship to kill the alien and is too late to turn it back off. In the second, it was the result of weapons being fired inside the plant that damaged the cooling system and set off a slow chain reaction.

* In ''Literature/{{Armor}}'' if a space marine turns on everything in their PoweredArmor on, the nuclear reactor power pack explodes violently.

* ''Series/{{Thunderbirds}}'': In "Danger at Ocean Deep", the ''Ocean Pioneer'' tanker inexplicably explodes, and Brains investigates the cause. With some help from Lady Penelope, he discovers it to be a chemical reaction between the cargo of liquid Alsterene and OD60, which is found in the sea. International Rescue set out to save the crew of the ill-fated ''Ocean Pioneer II''. One of the effects of the reaction is to cause the ship's reactor to go critical.

* One of the missions in ''[[VideoGame/ProPinballTheWeb Pro Pinball: The Web]]'' requires stopping a runaway nuclear reactor.

* In ''VideoGame/SyphonFilterLogansShadow'', one level has you aboard a recently sunk nuclear powered navy ship with the nuclear reactor about to "go critical" forcing you to hurry and shut it down by removing the fuel rods instead of inserting control rods as would be done in reality.
* The eponymous house in ''VideoGame/ManiacMansion'' was powered by a nuclear reactor which could explode if it overheated, if the house's power was turned off and the reactor short-circuited, or if the player pressed the [[SchmuckBait big]] [[DontTouchItYouIdiot red]] [[BigRedButton button]] in the pool. Probably {{Justified|Trope}} by the fact that the reactor is extremely poorly constructed due to the BigBad having a serious budget problem, to the point where he has to use ''his swimming pool'' to cool the fuel rods.
* ''VideoGame/{{Portal 2}}'': The Aperture Science Enrichment Center's nuclear reactor spends, all together, well over half the game either going critical or warning you that it's about to go critical.

* Justified in ''Anime/MobileSuitGundam'' and its subsequent sequels where Mobile Suits are powered by [[MinovskyPhysics Minovsky Particle]] reactors -- which explode only when hit by [[EnergyWeapon beam weapons]], and not if they're destroyed by conventional ordinance (In ''Anime/MobileSuitGundamF91'' the Shot Lancer is a weapon invented specifically to be able to hit a suit's reactor without making it go up, because when you're invading a space colony with the intent of moving your own population into it, you don't want to blow giant holes in it even time you destroy one of the defenders' mobile suits). This became a major plot element in episodes of ''Victory Gundam'' and ''The 08th MS Team''.
** However, there are some instances of explosions that are just plain silly. ''Anime/AfterWarGundamX'' shows a number of nuclear power plants abandoned AfterTheEnd that were not only apparently left running, but seemingly the slightest damage(or deliberate removal of certain components) would cause them to explode.

* As in its source material, the titular starship's dark matter drive explodes in ''FanFic/AuroraFalls.''

* In ''VideoGame/HaloCombatEvolved'', the eponymous ring, large enough to have its own ecosystem, is broken into pieces by throwing 4 grenades into a starship's engine containment field. The term used to describe it is "Wildcat destabilization". In reality, a fusion reactor can't go critical; rather than going out of control, the reaction just ''stops''. However, if, while the reaction is still functioning properly, one were to remove whatever is holding it in place (probably a magnetic field — the hotter fusion rockets would have to use those, rather than something made of matter, because even diamonds would vaporize on contact with the plasma), it would vaporize everything within a very large radius. Of course, it's unlikely one would have the time to get away before that happened.

* Element Zero core meltdowns are shown to be quite spectacular in ''VideoGame/MassEffect2: The Arrival''. When the cooling system of an "after-market eezo core" was deactivated it could detonate with enough energy to destroy a small planet; and a Mass Relay's core being destroyed has an effect comparable to a supernova.
** ''VideoGame/MassEffect1'' got there first. On Virmire, the Salarian [=STGs=] make a bomb out of their ship's eezo core with about the same yield as the bomb dropped on Hiroshima.
* This is the goal of the easy path's penultimate level in ''VideoGame/StarFox64''. The mission is to destroy the core of the Venom defense satellite "Bolse" to make the whole satellite explode. Interestingly, the [[AllThereInTheManual source material]] claims that the core uses Andross' trademark bio-mutated energy alongside traditional Nuclear power, explaining why Bolse explodes so spectacularly when you succeed in destroying it.

* There are quite a few in ''VideoGame/DukeNukem3D''.

* The ''{{Franchise/Alien}}'' franchise has done this twice - first with the reactor of the ''Nostromo'' in ''{{Film/Alien}}'', and then with the reactor of the atmosphere processor in ''{{Film/Aliens}}''. In the first example, this is because Ripley turns on the SelfDestructMechanism on the ship to kill the alien and is too late to turn it back off. In the second, it was the result of an accidental weapons discharge inside the plant that damaged some component and set off a slow chain reaction.

* Justified in ''Anime/MobileSuitGundam'' and its subsequent sequels where Mobile Suits are powered by [[MinovskyPhysics Minovsky Particle]] reactors -- which explode only when hit by [[EnergyWeapon beam weapons]], and not if they're destroyed by conventional ordinance (In ''Anime/MobileSuitGundamF91'' the Shot Lancer is a weapon invented specifically to be able to hit a suit's reactor without making it go up). This became a major plot element in episodes of ''Victory Gundam'' and ''The 08th MS Team''.

* In an issue of Franchise/TheDCU comic book miniseries ''ComicBook/IdentityCrisis'', [[spoiler:ComicBook/{{Firestorm}}]] is skewered by a sword, and is told to fly off for the safety of others as "everybody knows what happens if you puncture a reactor".

* ''WesternAnimation/GIJoeResolute'' has the "nuclear bombs converted into a reactor" justification, and Scarlett has no idea how Cobra did it.

* Justified in ''Anime/MobileSuitGundam'' and its subsequent sequels where Mobile Suits are powered by [[MinovskyPhysics Minovsky Particle]] reactors -- which explode when hit by [[EnergyWeapon beam weapons]], but not if they're destroyed by conventional ordinance (In ''Anime/MobileSuitGundamF91'' the Shot Lancer is a weapon invented specifically to be able to hit a suit's reactor without making it go up). This became a major plot element in episodes of ''Victory Gundam'' and ''The 08th MS Team''. However, there are some instances of explosions that are just plain silly.

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* There are quite a few in ''VideoGame/DukeNukem3D’’.
* VideoGame/{{Subnautica}} has the spaceship Aurora’s dark-matter reactor, which explodes, [[spoiler: releasing lethal radiation and requiring you to fix the reactor, or be overcome by radiation.]]

In fiction, the word "reactor" seems to mean [[SmallReferencePools exclusively nuclear reactions]], despite the word being common enough in chemistry since "reactor" simply means where a reaction happens. Another contrast between fiction and reality occurs with the term "critical". Fiction uses the word to say "it's going to explode!", whereas real nuclear physics use it to say "the reaction sustains itself", so a reactor is critical if it's ''on''. Relatedly, "supercritical" simply means the reaction is increasing in power, and a surge of power causes "prompt critical", which means the reaction is critical solely from the "prompt" neutrons created by fission events.[[note]]Since a neutron in flight cannot be controlled by processes working at human time scales, reactors are designed to be critical with the "delayed" neutrons released by subsequent isotope decay. This may have happened only once, in the [[http://en.wikipedia.org/wiki/Sl-1 SL-1 reactor accident]].[[/note]] (Designed bombs, on the other hand, go "[[UpToEleven prompt supercritical]]".) Also incorrect is "meltdown", meaning an explosion suspiciously similar to that of an atom bomb, or at least large enough to [[MadeOfExplodium blow the vehicle/facility in question to pieces]]. In real nuclear physics, meltdowns are just that - the fissile core ''melts'' into slag, hot enough to flash coolant into steam (wherein you get the associated bang) and possibly melt through the reactor vessel.

All reactors currently in use are designed with safe failure modes in mind; the worst you really get from a land-based reactor failing is to get a reactor container full of "corium"; super-hot and super-radioactive. The famous disasters are caused by the corium melting through safety features. On a sea vessel, the contamination would be [[UpToEleven horrific]]; the reactor mass would come into direct contact with the seawater, and shatter or even be entirely vaporized to small particles (fallout) in the massive subsequent vapour flash explosion. Radiation ''will'' be an issue inside the facility, and widespread fallout of the kind associated with nuclear war only occur when the containment systems have been ruptured. Long story short, a meltdown is extremely bad news, but orders of magnitude less bad than even small (i.e. tactical) nuclear weapons.

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* ''Series/EdgeOfDarkness'' has probably the most realistic depiction of a criticality event in any fictional work not directly based on a real one. It's outside a reactor, though.

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-> ''Surviving technician: "All you need to do is hit the scram button, its got this [[BigRedButton big red cover over it]]."''
-> ''Julian: (holds up button that was clearly ripped out) "You mean this?"''
-> ''Tech: "Yeah, that's it. [[OhCrap Shit]]"''.

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* In the ''Franchise/StarWars'' series, a proton torpedo to the Death Star's reactor causes the entire space station - which is the size of a small moon - to explode like a plastic model full of gunpowder. Although considering the energy output of the thing was enough to blow up an actual planet just as violently, maybe that's not unreasonable. ''Film/RogueOne'' reveals a [[JustifiedTrope justification]]: [[spoiler:Galen Erso, one of the Death Star's chief engineers and Rebel Alliance sympathizer, specifically designed the reactor system to suffer a catastrophic chain reaction when provided with the appropriate trigger.]]
* The arc reactor in ''Film/IronMan1'' isn't nuclear (in fact, it's safe enough that Tony Stark can walk around with a miniature one implanted in his chest), but under the right circumstances, can be triggered to produce a very satisfying boom.

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* "Blowups Happen" is a science fiction short story by Creator/RobertAHeinlein. The story is about a nuclear reactor which not only is in danger of exploding at any moment but is discovered to be capable of [[spoiler:destroying all life on Earth by having such a massive explosion that the Earth's atmosphere is blown away.]]

* As part of a military operation in one of the ''Literature/NewJediOrder'' novels, Admiral Kre'fey programs the reactor on a decommissioned and unmanned Interdictor cruiser to go supercritical once its shields go below 20%. Justified in that it was intentional, and also possibly justified because most ships in the ''Franchise/StarWars'' galaxy use hypermatter reactors, which work by technobabble.[[note]]Supposedly they forcibly pull tachyons out of hyperspace, which makes them self-annihilate.[[/note]]

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* Discussed and averted in the ''Series/StargateSG1'' episode "Learning Curve." When a prototype naquadah reactor is powered up, it causes a harmless distortion which sets off an alarm.
-->'''Hammond:''' In the future, Major, before you activate any device that includes the word "reactor," I would appreciate it if you would notify me.
** Of course, a bunch of later naquadah reactors explode, however they're almost always intentionally rigged to blow, like a real nuclear reactor. Naquadriah on the other hand is extremely unstable and explodes at the drop of a hat.
* ''Series/StargateAtlantis'', "Trinity": The team discovers [[spoiler:the Ancient equivalent of the Manhattan Project.]] Rodney tries to make it work, but it fails miserably.
-->'''Weir:''' You destroyed three-quarters of a solar system!\\
'''[=McKay=]:''' Five-sixths, but it's not an exact science.
** It becomes a Running Gag:
--->'''Lt. Col. Sheppard:''' It took Dr. Mc Kay years to figure out all things Ancient and he still doesn't completely understand.\\
'''Dr. Mc Kay:''' ''(defensively)'' I have a very firm grasp of Ancient technology.\\
'''Lt. Col. Sheppard:''' You've blown up entire planets, Rodney.\\
'''Dr. Mc Kay:''' That wasn't my fault!\\
'''Lt. Col. Sheppard:''' Well, it didn't do it by itself!
* ''Series/BabylonFive'' has exploding fusion reactors.

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* A major event midway through VisualNovel/AnalogueAHateStory. When it starts, you're given an ExactTimeToFailure of twenty minutes, and it's made pretty clear that this is not enough time to get out of the blast radius, despite the PlayerCharacter being in pretty much the best possible position to be doing so.

*** While preventing the warp core from breaching due to damage can be a daunting proposition, it ''does'' make for a very convenient SelfDestructMechanism: All that is required is to shut down the ContainmentField, which mostly requires the consent of several senior officers to get the computer to disable the failsafes. In ''StarTrekDiscovery'', we see a Federation starship manage this within a few seconds of being rammed by a much larger Klingon ship, [[TakingYouWithMe resulting in the destruction of both ships.]]

While there are no nuclear fusion reactors currently in service for power generation, all proposed designs would be even safer in the event of a failure, as without magnetic confinement of the reaction, it just stops.

* ''VideoGame/StarsInShadow'' has nuclear and fusion reactors outright labelled as "explosive" components, the same as ammunition stores. Missiles based on nuclear technology use their respective reactors as both the propulsion and the warhead.

* The eponymous house in ''ManiacMansion'' was powered by a nuclear reactor which could explode if it overheated, if the house's power was turned off and the reactor short-circuited, or if the player pressed the [[SchmuckBait big]] [[DontTouchItYouIdiot red]] [[BigRedButton button]] in the pool. Probably {{Justified|Trope}} by the fact that the reactor is extremely poorly constructed due to the BigBad having a serious budget problem, to the point where he has to use ''his swimming pool'' to cool the fuel rods.

All reactors currently in use are designed with safe failure modes in mind; the worst you really get from a land-based reactor failing is a get a reactor container full of "corium"; super-hot and super-radioactive. The famous disasters are caused by the corium melting through safety features. On a sea vessel, the contamination would be [[UpToEleven horrific]]; the reactor mass would come into direct contact with the seawater, and shatter or even be entirely vaporized to small particles (fallout) in the massive subsequent vapour flash explosion. Radiation ''will'' be an issue inside the facility, and widespread fallout of the kind associated with nuclear war only occur when the containment systems have been ruptured. Long story short, a meltdown is extremely bad news, but orders of magnitude less bad than even small (i.e. tactical) nuclear weapons.