Going Critical

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

— Russian joke

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 (as in a few microseconds, many orders of magnitude faster than you can say Oh, Crap!).^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.

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.

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.

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Examples

Nuclear Reactors

Anime and Manga

• After War Gundam X shows a number of nuclear power plants abandoned After the End that were not only apparently left running, but seemingly the slightest damage(or deliberate removal of certain components) would cause them to explode.

Documentaries

• Aftermath: 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.
• In both Real Life and Chernobyl, the insertion of the reactor's graphite-tipped control rods into an already-critical reactor caused it to go supercritical for a brief 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 (bad), allowing oxygen to rush into the reactor (filled with fuel and graphite that's about the temperature of Satan's asshole), which caused an even bigger explosion a few seconds later that destroyed the roof of the building (very bad) and caused a graphite fire pushing radioactive crap into the atmosphere (catastrophically bad). And because the reactor fuel is still insanely hot and undergoing fission events it can't be put out with water like a normal fire. Nuclear scientist Legasov is, however, concerned that if the mixture of melting fuel, powdered boron (meant to poison^*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 2-4 megatons (read: million tons of TNT), 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 dropped into the reservoir at once (and then in a wide pattern that would maximize flash-heating). Sub-trope of Scary Science Words.

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 (it disabled the reactor's cooling systems and deliberately put it into an unsafe state and is otherwise rather plausible — it was too far gone once the cut-off time had expired). 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 (this was stated to be a fusion reactor so is a lot less plausible).
• Brooklyn Tide: The cyber-weapon acting as the MacGuffin supposedly has the capacity to cause a nuclear power plant to have a meltdown, which is why the antagonist, Jonathan Clay, wants it.
• 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).
• Discussed in K-19: The Widowmaker. The reactor's cooling system bursts and the crew attempts to SCRAM the reactor, but without the coolant, the reaction will still continue to build to runaway proportions. Eventually, it'll hit 1,000°, and then "nobody knows." The film's page states that, if the core had gone into meltdown and hit the ice-cold seawater, "you'd be hard pressed to find any part of the sub bigger than your hand." The major concern is that this will set off the ship's nuclear missiles (which is actually impossible to do by accident, nukes being surprisingly finnicky weapons).
• The malfunction in the spaceship's fusion reactor in Passengers (2016) 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 (1978) 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'. As a matter of fact, fuel rods made of weapons-grade fissiles just react longer due to the removal of anything that would choke up the reaction (substances known as "nuclear poisons").

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.
• An attempted justification occurs in DOME by having the reactor core run on weapons-grade plutonium instead of weapons-incompatible uranium 238, the in-universe explanation being that the molten fuel rods will solidify as a critical mass once they splash into what's left of the liquid sodium coolant.
• The basic plot of The Dorset Disaster by Aleksander Sidar is a nuclear power plant doing this and exploding.
• 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

• Chernobyl is Exactly What It Says on the Tin, showing the consequences of, and investigation into, the real-life Chernobyl Reactor 4 accident of April 26th 1986. In the final episode, Legasov, after having described the chain of events leading up to the moment of the explosion, delivers the portentous line "Reactor 4 is now a nuclear bomb." This is inaccurate (although allowable both in-universe and out as dramatic license to hammer home a point), as an atomic-bomb style supercritical event is considered to be merely a possible, and relatively small, part of everything that went wrong that night. A Nuclear Engineer discusses this here.
• 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.

Tabletop Games

• BattleTech averts this trope, as the mech will shutdown before the reactor goes critical. However, there are still other effects for the mech overheating, such as ammunition explosions, damaging the mech warrior, or slowing down the mech.

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.
• Unsurprisingly, this is a recurring concept in Fallout:
  • In Fallout 2, the Chosen One destroys the Enclave and their Oil Rig base by sabotaging the nuclear reactor powering it, leading to a massive mushroom cloud in the ending cinematic.
  • In Fallout 4, this is how you destroy the Institute, which is hidden deep beneath M.I.T in the ruins of Boston, by putting a remote-controlled explosive in the sophisticated nuclear reactor their facility uses.
  • This is even part of the backstory, it's been mentioned in the series timeline that in 2065, about 12 years before the Great War, a nuclear reactor in New York almost went critical due to the enormous power demands of that summer, forcing the U.S to start rationing electricity.
• 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.
• MechWarrior:
  • The mech will shut down if it overheats. This may be overridden, at the risk of the reactor blowing up, among other possible effects. In case of MechWarrior 3, the mech will self-destruct when the heat reaches a certain threshold without an intermediate shutdown, such as when the Supernova performs an alpha-strike.
  • If the center torso is destroyed, the reactor may go critical. In case of MechWarrior 4, the reactor will always explode.
• 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.
• One level in Syphon Filter: Logan's Shadow 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?
• 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 big red cover over it.
  Julian: [holds up button that was clearly ripped out] You mean this?
  Tech: 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, resulting in an Instant Cooldown. 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."
  • In one episode, Homer triggered a meltdown in a simulator. It had no nuclear material with which to accomplish this.

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Sci-fi reactors

Anime and Manga

• Nicely averted in Cannon God Exaxxion; one particularly graphic scene features fusion-powered machinery that has been damaged by an explosion. Instead of blowing up real good, the stuff starts leaking hot plasma & horrifically burning anybody who gets near it.
• Third-generation Arm Slaves in Full Metal Panic! are said to use palladium reactors (older ones run on diesel/gas turbines). Judging from the Helmajistan ambush, these things pack quite a punch. One might even mistake the self-destructing Codarl at the end of the first season as a meltdown but he explicitly states that he packed a few hundred kilos of high explosive to make sure he can pull off a Taking You with Me. On the other hand, the onboard AI warned him that if he starts the sequence, there's no cancelling it. So he might have gone for a straight overload spiced with some extra HE for a bigger boom.
  • Palladium reactors are a real-life contraptions — they were proposed as vessels for the (sadly debunked) cold fusion. The fusion being cold, their best effort in blowing up probably would've been no more than a tank worth of gas. Enough to kill a person, but really nothing to write home about.
• This happened to Precia's Mana reactor in the backstory of Magical Girl Lyrical Nanoha, although the movie shows that this mainly happened because corporate executives took her out of the decision making process and pushed for it to be used before the safety measures were fully tested.
• Justified in Mobile Suit Gundam and its subsequent sequels where Mobile Suits are powered by Minovsky Particle reactors — which explode only when hit by beam weapons, and not if they're destroyed by conventional ordinance (In Mobile Suit Gundam F91 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.
  • In Mobile Suit Gundam SEED Destiny, when Shinn's Impulse stabs Kira's Freedom. the latter doesn't blow up because Kira's able to shut off the power to the nuclear-powered MS, but it gets ripped to pieces due to the supposed destruction of the Archangel (which was actually one of its engines being struck).
• Rebuild World: Lost Technology knives, as well as Shiori’s katana which is based on similar designs, can have the safety shot off which makes it into a Laser Blade for only a few seconds, but said blade has Absurd Cutting Power. Doing this makes the rest of the knife disintegrate (or with Shiori’s katana, just the blade needs replaced).

Comic Books

• In an issue of The DCU comic book miniseries Identity Crisis (2004), 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". If they meant that a containment breach causes a potentially deadly radiation leak, this would've been forgivable.

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.
    • 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.
  • In the Original Series episode "The Doomsday Machine", 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.
  • In the Original Series episode "The Devil in the Dark", the Janus 6 mining colony is powered by a PXK pergium reactor, which seems to be an advanced type of fission reactor. When the Horta steals the coolant-circulating pump for the reactor cooling system, it sets the reactor on a build-up to catastrophic failure. Scotty jury-rigs a replacement circulating pump, but it doesn't last long. If the missing pump isn't found soon, the reactor will "go supercritical" and cause an accident that will contaminate "half the planet." There's a little justification here, in that a fission reactor generates huge amounts of heat even when it's shut down. If the heat isn't removed, the reactor core will melt. A meltdown and containment breach in an underground tunnel system would indeed spread radioactive contaminants over a huge volume of the tunnels.

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. Ditto for the Clan-made Improved Heavy Laser class of weapons. Damage to a normal laser tends to ruin either the focusing lens or the power supply, causing it to shut down, but a Improved Heavy Laser power supply is much touchier and will explode when damaged.
• 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

• There are quite a few in Duke Nukem 3D.
• In Half-Life 2, A dark matter reactor in a Doom Fortress is enough to fling cars into the air and knock a train off its tracks at least a mile away. Justified in that the Combine forces were very specifically trying to get the dark matter reactor to explode.
• In Halo: Combat Evolved, 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 Mass Effect 2: 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.
  • Mass Effect 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.
• Used to a degree in the course of the later games in the MechWarrior series, 3 and 4 to be precise. Previous games had Mechs either explode into pieces or be rendered a standing but inert corpse (most likely as a limitation of the early game engines). 3, however, first introduced dramatic heat induced deaths. One might expect the normal death animation to play where the 'Mech catches fire, its torso goes up in flames, and it falls over amid a shower of ruined internal structures spewing from the machine. Not so. Instead, a Mech destroyed by excess heat goes up in a highly damaging mushroom cloud, almost certainly invoking this trope. MechWarrior 4 simply had every destroyed Mech spew streams of blue-white light from its core as it fell, before exploding into chunky rubble loosely resembling the original chassis.
  • The Trope is invoked by name in the opening cutscene of MechWarrior 3 as well, here. The resulting explosion's shockwave evokes comparisons to nukes proper, or at least is so violent that it flattens buildings for a considerable radius and convinces the pilot of a 100-ton Assault Mech to get out of there in a mighty big hurry.
  • The second game of the series did it too. There were no huge balls of blue light or mushroom clouds, but the killed mech would be torn apart by a series of fairly small explosions, implied to be caused by weapons and the reactor. Stepping into the mess would cause damage to your Mech's legs.
  • The Crysis Warhead mod, MechWarrior Living Legends, takes the critical explosions of the previous games up to eleven - when a mech goes critical (20% chance when destroyed), it glows white while a low sound builds up, then explodes in a huge, blindingly white mushroom cloud, stirring up dust which obstructs the battlefield. Any battlearmor nearby either get gibbed or have their heads up display scrambled from the electromagnetic pulse.
• The first stage of Kreed. You're trying to prevent a reactor meltdown aboard one of the space stations, and you need to locate and activate various control panels to lower the temperature while fending off assorted alien creatures along the way.
• Ironically averted in Metroid Fusion. For a series with so many catastrophic countdowns, the main reactor-related emergencies in Fusion aren't explosive. In the first instance, the cooling systems in the high-temperature habitat are deliberately shut down, risking a boiler explosion; in the second, vines invade the reactor and SCRAM it. The later destruction of the station is caused deliberately by running it into the nearby planet at the same time the colony's self-destruct goes off.
• This is the goal of the easy path's penultimate level in Star Fox 64. The mission is to destroy the core of the Venom defense satellite "Bolse" to make the whole satellite explode. Interestingly, the 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.
• Subnautica has the spaceship Aurora’s dark-matter reactor, which explodes, releasing lethal radiation and requiring you to fix the reactor, or be overcome by radiation.
• Hardspace: Shipbreaker: Early into the game, ship reactors become just another piece of the vessel you must salvage, even if they're all somehow still active and eager to start melting down as soon as you pull them off their base. Class 1 ones are small and can just be yanked out and shot into the Salvage Barge without much trouble, Class 2 reactors are usually buried more deeply and need you to either be really quick in getting them out after clearing most of the ship out of the way, or carefully cut off fuel and coolant flows (unique to them) to give yourself a more lenient time limit. Both classes start sending lightning arcs everywhere after a few seconds, and both will detonate and utterly trash the ship they're in if you're too late.

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

• In The Batman episode "White Heat", when Firefly absorbed a large amount of radiation. Batman said a meltdown wouldn't be a nuclear explosion because he didn't absorb enough radiation, he would just let out enough heat and radiation to destroy most of Gotham. Then he tried to use it to set off an actual nuclear reactor.
• In Batman: The Animated Series, Baby Doll rigs the power plant to explode by shutting down the coolant and regulators.

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