http://tvtropes.org/pmwiki/pmwiki.php/Main/GoingCritical

Russian joke "Last night Chernobyl nuclear power plant fulfilled the Five Year Plan for heat energy generation in four microseconds."

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Sci-fi reactors are usually based on the idea that a nuclear reactor is a continuous nuclear explosion in a really strong box. Therefore, reactors are a type of Sealed Evil in a Can, just waiting to blow the hell out of everything once the shielding is cracked. Calling any device a "reactor" creates the expectation of an explosive reaction. There are other names that can be used for this event; "meltdown", "destabilizing", "going critical", or something more fanciful.

In fiction, the word "reactor" seems to mean 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 imminent.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 SL-1 reactor accident . (Designed bombs, on the other hand, go "prompt supercritical".) Also incorrect is "meltdown", meaning an explosion suspiciously similar to that of an atom bomb, or at least large enough to 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.

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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", which is essentially lava formed from whatever was in the reactor core at the time and is as radioactive as you'd expect from a reactor's worth of nuclear fuel. The famous disasters are caused by the corium melting through safety features. On a sea vessel, the contamination would be 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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This trope is even less realistic when dealing with nuclear fusion. While there are no 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.

A subtrope of Artistic License  Nuclear Physics. See also Containment Field. When a reactor "goes critical" but is then turned off with no consequences, it's Instant Cooldown.

Examples

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Nuclear Reactors

Documentaries

Aftermath: Population Zero: Because the presently active nuclear power plants across the globe are no longer being manned after humanity's disappearance, it's only a matter of time before they go into nuclear meltdown. Whole regions are turned into death zones for decades to come for any animals trying to survive.

Fan Works

Averted in Heroes of the Desk: Repercussions—a US supercarrier is sunk in shallow water but the Navy gets the situation under control. Of course, since this trope exists, some people panic anyway even though nothing bad happens.

Film  Animated

In Pinocchio in Outer Space, an ancient Martian nuclear plant explodes like an A-bomb (complete with mushroom cloud).

Film  Live Action

The Alien franchise has done this twice - first with the reactor of the Nostromo in Alien, and then with the reactor of the atmosphere processor in Aliens. In the first example, this is because Ripley turns on the Self-Destruct Mechanism 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 The Dark Knight Rises, a physicist finds a way to turn nuclear fusion reactors into multi-megaton nuclear bombs by making them "go critical". Not only is it completely impossible in real life to do so, but the process (supposed to be complicated enough that the physicist is the only person in the world to understand it) takes at most a few minutes, on a reactor design he has no way of being familiar with, and afterwards you can extract the "core" (whatever it is) from the reactor and use it as a highly portable nuclear bomb that can't be defused. Awesome, really.

In Godzilla (2014), the male Muto played a major role in the Janjira disaster. A possible subversion in this case, because the story of the Janjira reactor going critical was all part of the coverup to hide their existence.

Holocaust 2000: Robert's company is working on building a new type of nuclear power plant in the Middle East that could provide energy for the entire Third World. The project garners masses of protestors because it could end up causing a meltdown that would result in nuclear stockpiles all over the world blowing up (exactly how this would work is never addressed).

The malfunction in the spaceship's fusion reactor in Passengers2016 is treated like a malfunction in a nuclear fission reactor. More likely it would just completely shut the thing down rather than go out of control as depicted.

At the end of Resident Evil: Apocalypse, 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 Swarm had a bunch of killer bees turn a nuclear power plant into a nuclear bomb in less than a minute, somehow.

In the James Bond movie The World Is Not Enough, The Dragon 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'.

Literature

In Armor if a space marine turns on everything in their Powered Armor on, the nuclear reactor power pack explodes violently.

Made a Justified Trope with the ultimate killer of most defeated starships in Honor Harrington. It turns out that 41st century fusion reactors keep their plasma fusing by the "simple" expedient of compressing them to stellar pressures using a gravity-based Containment Field. This makes for reactors that produce much greater output than more traditional fusion reactor designs, as per several infodumps in various places. However, the nasty side effect is that even though a breached fusion reactor instantly stops reacting (just as in a real-life fusion reactor), the pre-existing heat and pressure still make a truly satisfying kablooey.

Averted in the novel The Hunt for Red October: fatigue-induced failure of an important valve in the cooling system for the reactor of a Russian submarine causes a meltdown in its reactor, which in turn creates a glob of radioactive slag that melts its way through the bottom of the sub, eventually sinking it.

Discussed in Mikhail Akhmanov's Invasion by the three admirals of the United Space Forces in the wake of the Lark's disappearance. The official story is that the cruiser's reactor experienced a meltdown and destroyed the ship. However, the admirals discuss the possibility and list three cases of reactor exploding in outer space and cite that those were either obsolete reactors on non-USF ships or the result of micrometeorites damaging the cooling systems. Played straight during the Battle of the Martian Orbit, when one USF cruiser is described as being destroyed, when her armor was punched through by an Anti Matter blast that impacted the reactor chamber. However, even if the reactor didn't explode, the anti-matter would've destroyed the ship anyway.

Live-Action TV

Edge of Darkness 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.

Knight Rider 2008, "Knight of the Iguana". According to KITT and Doctor Graiman, being hit by the Stolen Military Uber-Missile of the week will cause a California nuclear power plant to explode — complete with the Deadliest Mushroom, turning into a giant atomic bomb. Mind you, it may have been their intent that this have something to do with the specific and unusual nature of the missile used. But it's more likely just that this show plays hard and fast with the laws of physics.

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 OD-60, 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.

In the Torchwood episode "Exit Wounds", a bunch of bombs went off, causing all electricity to cease, which caused a reactor to go critical. In cooling it down, Owen died. The reactor pretty much had the same thing happen to it that the reactors in Fukushima did. The meltdown wasn't the unrealistic part. The unrealistic part was where Owen fiddled with controls (somehow flooding the control room with radioactive coolant) and safely shutting down the reactor. This episode probably belongs under Instant Cooldown.



Music

The music video of the song "Dancing with Tears in my Eyes" by the band Ultravox features a nuclear power plant accident which should result in an explosion according to some warning signs. The explosion is implied to even hit a house which is in a rather large distance to the power plant. (And killing the family of the plant worker which is the protagonist of the video.)

Pinball

The "Meltdown" mode in Judge Dredd also requires stopping a runaway reactor.

The main playfield toy of Operation: Thunder is a Domed Power Plant; players must shoot balls inside it to strike all of the targets and make it explode.

One of the missions in Pro Pinball: The Web requires stopping a runaway nuclear reactor.

Total Nuclear Annihilation centers on starting and overheating nine different nuclear reactors, causing them to explode.

Video Games

A major event midway through Analogue: A Hate Story, when the Mugunghwa's main reactor - which has gone some six hundred years in low-power mode without proper maintenance - starts failing. When it starts, you're given an Exact Time to Failure of twenty minutes, and it's made pretty clear that this is not enough time to get out of the blast radius, despite the Player Character being in pretty much the best possible position to be doing so.

BioForge: Stopping a moonbase nuclear reactor from meltdown is one of the things you've got to do.

In Fallout 2, the Enclave Oil Rig's reactor goes up in a big nuclear explosion.

Hatred has you causing one of these at a nuclear power plant in the final sequence of the game, with the aid of two bundles of C4 explosive stolen from a military base .

. The eponymous house in Maniac Mansion 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 big red button in the pool. Probably Justified by the fact that the reactor is extremely poorly constructed due to the Big Bad having a serious budget problem, to the point where he has to use his swimming pool to cool the fuel rods.

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.

Stars In Shadow 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.

In Syphon Filter: Logan's Shadow, 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.

Web Comics

Justified in Sluggy Freelance when Riff's "Mini Fission Comrade " starts to have a meltdown. Tech Support: Now sir, what's really the difference between a personal fission reactor and a refurbished old Soviet Union black-market suitcase-nuke?

" starts to have a meltdown. Played realistically in an arc of S.S.D.D where a heavily sabotaged fission reactor is about to meltdown. The main risk is stated to be the radioactive and very hot water flooding the ship's decks. Surviving technician: All you need to do is hit the scram button, it's got this

Julian: [holds up button that was clearly ripped out] You mean this?

Tech: Yeah, that's it. All you need to do is hit the scram button, it's got this big red cover over it [holds up button that was clearly ripped out] You mean this?Yeah, that's it. Shit

Western Animation

G.I. Joe: Resolute inverts the trope, with Cobra forces having turned a Nuclear missile into a power source. Lampshaded with a line from Scarlett saying she has no idea how Cobra does it.

Pretty much any accident or potential accident involving the Springfield Nuclear Power Plant on The Simpsons is portrayed as a nuclear explosion, including one where Professor Frink projected everyone in a large radius would be killed instantly. In the episode "Homer Defined," the reactor begins to go critical, and Homer (of course) does not remember his training for what to do during this very event. He picks a button at random with "Eeny Meeny Miney Mo"...and luckily for him, that's the button to initiate the SCRAM procedure. Everyone makes him out to be a hero, but he feels guilty because it was nothing more than luck. Another episode "King-Sized Homer" had Homer gain weight so he could be considered morbidly obese enough to work from home. But then he decides to go see a movie, leaving a drinking bird in charge of the computer...which fails, and he has to go to the plant to stop the meltdown. He nearly falls to his death trying to press the manual shutdown button, but falls into a gas vent pipe , shutting down the reactor and preventing the release of radioactive gas by plugging the hole he fell into with his girth. Earlier in that episode, Homer's computer asks "Vent radioactive gas?", when Homer responds no the computer insists "Venting prevents explosion." Which becomes a "Funny Aneurysm" Moment when in Fukushima reactor technicians did exactly that. And it still didn't prevent the explosion. In one episode, Homer triggered a meltdown in a simulator. It had no nuclear material with which to accomplish this.



Sci-fi reactors

Anime and Manga

Comic Books

In an issue of The DCU comic book miniseries Identity Crisis, Firestorm

Fan Works

As in its source material, the eponymous starship's dark matter drive explodes in Aurora Falls.

In Heroes of the Desk: Repercussions, an escort ship is attacked by an 0-23-8, resulting in a reactor explosion. Seeing this happen, the ship it is protecting promptly shuts down its own powerplant to avoid a similar fate. Given that the attacker is a 4-dimensional being that can reach inside anything 3-dimensional and rearrange whatever it wants, it's not hard to see how pulling a few wires might make things go boom.

Film  Live Action

In Galaxy Quest, the reactor of the NSEA Protector is approaching a core meltdown while under attack. We don't get to see what happens next.

The arc reactor in Iron Man 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.

In the Star Wars 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. Rogue One reveals a justification: 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.

Literature

We also see this in BattleTech fiction, where BattleMechs are routinely powered by fusion engines that sometimes explode from taking sufficient damage — the explosion isn't actually described as of nuke-caliber, but can inflict quite some damage on anything nearby. One rulebooks hangs a lampshade on this by patiently explaining (as part of a in-universe lecture on 'Mech systems) that such explosions are not, in fact, nuclear. Just how much more plausible the suggested alternative of air rushing into the breached reaction chamber, promptly getting heated up to several thousand degrees, and thereby causing the observed 'fireball' is a mystery. "Stackpoling" is the term in the fandom for a Battlemech's reactor doing this, due to author Michael Stackpole using this trope repeatedly in his novels.

"Blowups Happen" is a science fiction short story by Robert A. Heinlein. 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 destroying all life on Earth by having such a massive explosion that the Earth's atmosphere is blown away. Heinelein gets a pass on poor science for an impeccable reason: He wrote "Blowups Happen" in 1940 . The theory that a nuclear power plant would be a barely-controlled bomb was eminently Fair for Its Day - it was written two years before the world's first (highly classified) reactor was built.

Star Wars Legends: As part of a military operation in one of the New Jedi Order 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 Star Wars galaxy use hypermatter reactors, which work by technobabble. note Supposedly they forcibly pull tachyons out of hyperspace, which makes them self-annihilate.

Live-Action TV

Babylon 5 has exploding fusion reactors.

Doctor Who: In "The Doctor Dances", a Noodle Incident where the Doctor made the main reactor of the weapons factories of Villengard go critical is mentioned. This caused the factories to be vapourized.

Stargate: Discussed and averted in the Stargate SG-1 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. Stargate Atlantis, "Trinity": The team discovers 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!

In Star Trek, most reactors contain anti-matter. Should the containment fail, the anti-matter would contact normal matter. This results in a massive explosion. Aside from the Romulans (see below), the Borg are the only race who don't use M/AM reactors for power. Their power sources run on pure technobabble, it seems. The Romulans in Star Trek use captured quantum singularities (black holes). Whether matter/antimatter is safer or not is something of a moot point. In addition to the anti-matter used in warp reactors, impulse (STL) drives are fusion-powered. Apparently, their containment systems are a lot better than what the FTL drives use, as impulse reactors never seem to explode (unless deliberately rigged)... Fusion powered reactors can't blow up. Howeverdepending on the designif they lose containment on the plasma, it will escape. Generally the reaction will cease, since every form of fusion needs to put the plasma under massive pressure...but the plasma might well vaporize the ship as it escapes. In "The Doomsday Machine" (episode of Star Trek: The Original Series), Scotty jury-rigs the badly damaged U.S.S. Constellation so that its impulse drive can function. He says repeatedly that keeping it from exploding is taking all of his effort. While preventing the warp core from breaching due to damage can be a daunting proposition, it does make for a very convenient Self-Destruct Mechanism: All that is required is to shut down the Containment Field, which mostly requires the consent of several senior officers to get the computer to disable the failsafes. In Star Trek: Discovery, we see a Federation starship manage this within a few seconds of being rammed by a much larger Klingon ship, resulting in the destruction of both ships. This is also stated to be the reason why Federation starships have their distinctive -_—- shape. If the engines started to go ka-blooie, they or the saucer portion of the ship could be detached and give the crew a chance to escape the blast. Mind you, this was not a grantee; The Enterprise-D tried this tactic in Generations, and while they did avoid becoming space dust, the blast still caused the Saucer to crash into a nearby planet.



Tabletop Games

In BattleTech, Battlemechs with their fusion reactor shielding shot out don't explode at all, unless you're playing with optional rules to make it more 'cinematic' - though even then, the explosion is more or less like a boiler explosion than a nuclear explosion. The real explosion danger comes from ammunition explosions, from either a stray laser blowing up all your autocannon rounds, or the heat of your engine causing the ammo to 'cook off'. The amount of ammo involved usually means this will gut your 'mech. Even the humble machinegun, the weakest ballistic weapon in the game, carries at minimum a half-ton of ammo and will ruin anything that is carrying it if that ammo lights up. This adds to the competitive balance: Energy weapons fail gracefully if hit (so the only way to stop a laser-boat quickly is by managing to hit the cockpit, failing that, you're going to have to keep walloping away at it.) but promote overheating. Missile and autocannon weapons have high strength to weight, but there's always the possibility of instant death by lucky shot. Something like this trope is invoked with Gauss weaponry. The ammo is just an inert metal slug, but the capacitors that power the gun's electromagnets are prone to catastrophic explosion if they get hit.

In Mindjammer Zip (zero-point energy) reactors tend to explode when heavily damaged. Especially the improvised ones used by the Venu Empire, the Commonality has developed a weapon specifically to destabilize their reactors.

Video Games

Web Comics

Schlock Mercenary: Reactors work through neutronium (extremely dense matter, held together by its own gravity) annihilation, which are usually kept controlled by their reactor AI and multiple fail-safes, including an auto-shutdown feature that stops the reactions and turns the reactor into an inert ball of neutronium. While hard to do and usually impractical (to the degree that killing the rest of the ship first is usually quicker and safer), cracking an 'annie-plant' is possible and happens several times during the comic, leading to a pile of evaporating, very explosive neutronium. This, however, is peanuts compared to what happens if the reactor AI decides to actively go in for using the plant as a conversion bomb. Tagon: The base's annie-plant blew. That distinctive "skoom" noise would be the pile evaporating.

Pranger: Do you mean to tell me that you've been close enough to hear an annie-plant go up?

Tagon: Twice in the past three months. Remind me to tell you about my short, furry employer.

Pranger: I'll buy the beer, Captain. I'll buy the beer. Not to mention that Sgt. Schlock's fusion-powered plasguns tend to explode at the drop of a hat.

In S.S.D.D the backpack fusion reactors in Black Rose Plasma Cannons explode so often they have a rep for killing more friendlies than enemies. However it's explained that ship-sized reactors are perfectly safe, when a backpack reactor's containment is breached the plasma licks the walls and superheats them, larger reactors have enough space for it to dissipate harmlessly.

Western Animation