Artistic License Nuclear Physics

"Martin: I thought getting hit by an atomic bomb would've killed him. Bart: Now you know better."

- The Simpsons

Both nuclear weapons and peaceful nuclear technology are enormously technical in nature. Since Hollywood never lets boring facts get in the way of an engaging yarn, this allows some truly mind-bending violations of physics to make it by most audiences. They can basically be summed up like so:

 Ideas that look good on paper: 

Idea 1: My Nuke is GOING CRITICAL
 * 1) Related to Reliably Unreliable Guns and Stuff Blowing Up, if something is nuclear, and something, anything happens to it, it's Going Critical and gonna blow up like an atomic bomb. It doesn't matter if it's designed not to do that, it doesn't matter if it's not fissile enough to be used for an atomic bomb, it doesn't matter if it hasn't got enough material for critical mass, it's gonna blow.
 * 2) * In real life, a nuclear weapon requires precise conditions to achieve a full-scale explosion, while fictional nukes act like spheres filled with mega-nitroglycerin. Shooting or even blowing up a real-life nuclear weapon with conventional explosives is likely to disable the warhead, not set it off.
 * 3) ** In fact, here's a film produced by the US Air Force back in 1960 showing nuclear weapons being purposely dropped out of planes, set on fire, and otherwise subjected to movie-of-the-week hijinks to demonstrate that rough treatment of nuclear weapons does not result in said weapons detonating.
 * 4) * If a reactor does melt down or is going to melt down, the hero usually has to manually initiate a SCRAM, an emergency shutdown, sometimes going to elaborate lengths to set the SCRAM up or even having to manually insert the control rods into the reactor one at a time. This is as opposed to real life, where it's typically an automatic safety feature which engages if the reactor shifts outside a certain set of safe operating parameters and where a manual reactor SCRAM is as simple as turning a switch. A switch that usually exists in multiple redundant locations both near and far away from the reactor room, so that you can always reach at least one during an emergency. (For one example, the nuclear reactors used in US Navy submarines have almost a dozen different ways you can drop the rods with a single action, at least two of which don't even require you to be in the engine room.)
 * 5) * Occasionally, a story tries to justify the above trope by noting 'normally we'd just turn the SCRAM switch, but the damage to the system makes that impossible so (insert elaborate heroic jury-rigging here)'. In real life, the SCRAM systems on modern reactors are designed so that they require 100% system uptime to actively prevent the SCRAM from happening -- if the reactor breaks, the very act of that breaking will automatically SCRAM the pile. Usually this is accomplished by having the rod mechanisms constantly pushing against a spring, or being held up by an electromagnet. If power to the safety systems is interrupted even for a moment, the mechanism stops resisting and the reactor shuts down.
 * 6) * Similarly, fictional nuclear reactors will melt down or go up in gigantic nuclear explosions at the slightest thing going wrong. A nuclear reactor simply doesn't have the level of reactivity to cause a full-scale nuclear explosion, and modern reactors tend to have self-engaging safety features in addition to manual ones; for example, as the temperature rises above a given threshold, they will automatically shut down. If a lack of coolant flow is detected, they will automatically shut down. Etc, etc. This is intentionally very different than the one at Chernobyl.
 * 7) * Assuming that a reactor SCRAM / shutdown means the absolute end of a casualty. A reactor "shutdown" simply stops fission; the radioactive decay of fission products inside the reactor still produces a significant amount of heat -- enough in the case of Three Mile Island (which was SCRAMmed very early in the timeline of the casualty) to damage the core and release radioactive material into the environment. The reactors in Fukushima were shut down upon the initial earthquake and still produced enough decay heat days later to cause full meltdown and hydrogen explosions. Even worse, at Chernobyl, the SCRAM signal aggravated the casualty (inside baseball: the control rod followers were made of neutron-transparent zircaloy, and replaced neutron-absorbing water in the control rod channels, causing a temporary spike in fission events before the even-more-neutron-absorbing boron control rod body was in place, driving the reactor over the edge into prompt criticality).
 * 8) * In fiction, a reactor melting down is always a Chernobyl-level catastrophe regardless of design. Most of the consequences of the Chernobyl meltdown were a direct result of the plant being built without a containment building, a structure that surrounds the reactor itself and is intended to reduce any consequences of a leakage or meltdown. These work rather well: in the third-worst reactor disaster, on Three Mile Island, the containment building duly contained the steam and other bad effects of the meltdown. No pyrotechnics; in fact, the radiation released from Three Mile Island was less than the radiation coming from your computer monitor.
 * 9) ** Even in the SL-1 incident in 1961 (the only fatal reactor accident in the United States and another example of terrible control rod design), which lacked a designed containment building, the regular old building contained most of the radioactivity. Hell, even with that, it proved that the core and water coolant vaporizing would prevent the core from melting down.
 * 10) ** Chernobyl's core of uranium fuel was surrounded by graphite, making the reactor a giant block of charcoal waiting to ignite into carbon-14 => radioactive CO2 goodness. British nuclear power plants also use graphite as the moderator, except for Sizewell B, but they use carbon dioxide gas as coolant where Soviet reactors used water. It was the combination of graphite moderator and water coolant that made Chernobyl a death trap.
 * 11) ** In addition, the conditions for Chernobyl accident were caused by 'scientists' performing experiments during the night shift, were an inexperienced crew, basically only capable of following directions from a manual, were not aware of, or able to properly react to, the conditions before it was too late to save the reactor. What happened was the scientists removed all the control rods, causing the reactor to heat up. When it got WAY too hot, they tried to fix it by fully inserting all the control rods. the rods promptly blew the fuck up. It was not actually a nuclear blast, it just threw radioactive shit everywhere.
 * 12) * Despite the common trope of villains (less commonly: the hero) stealing nuclear reactor fuel rods to build weapons out of, in real life, reactor fuel and weapons material are not interchangeable. The former simply does not have the enrichment levels and purity needed for the latter. And while plutonium from dismantled nuclear weapons is in fact recycled as fuel, it's never shoved into a reactor as-is - it's blended with natural or depleted uranium until only a few percent of the original weapons-grade plutonium remains in the mix. In short: reactor fuel just doesn't have what it takes to go boom.
 * 13) And on the subject of Criticality, any time some thing goes wrong in a nuclear facility, terrified screams of "It's Going Critical" will fill the air, or the villain's plan will be to make the reactor go Critical. "Critical" means that the reaction is self sustaining and that the reaction is proceeding at a constant level -- in other words, a critical reactor is one that is operating at a steady constant power level. One more time, "Critical" reaction is the normal operating condition of a nuclear reactor. Super-Critical, while not used despite sounding definitely bad, simply means that the reaction is steadily gaining power, or simply, someone getting powered by the reactor turned on a light and so the reactor went temporarily super-critical to increase its energy output for the new drain. Finally, there IS a condition that would (almost) elicit the reactions of a Hollywood type critical reactor. It's called Prompt-Critical, and if a reactor has had this happen, there'd be no running around trying to prevent it or saying it happened; by the time any readings showed this happening, it would already be too late, and either the automatic safety systems would have kicked in and shut down the reactor, or the reactor pile would be an actual pile of slag.
 * 14) * Due to the above-mentioned misconception of "critical mass", it's Hollywood-assumed that any minor wrong could send a nuclear reaction to prompt-critical. This is not practically the case, because, as we should more accurately speak of "critical density", most nuclear reactors are designed to stay below that at any time, including loss-of-coolant situations.
 * 15) ** Most commercial reactors are cooled and moderated by water; a loss of coolant would risk fuel melting, but the reactor would go subcritical from the loss of coolant.
 * 16) * This comes from the Hollywood idea of reactors as bombs-in-waiting. When a nuclear bomb "goes critical", it's actually going Prompt-Critical which is why it explodes, thus when a reactor goes critical, it becomes a bomb and explodes.
 * 17) The reactor core is inside the cooling tower. Because most people associate "nuclear power plants" with those giant hyperboloid structures as seen on The Simpsons, it's an easy mistake to assume that they are the plant and contain the reactor. In reality, the reactor is typically located in a separate block-shaped building (which ideally serves as a containment), and the towers are just the enormous radiators that contain and manage the cooling water. There are other types of power plants (such as coal plants) that have cooling towers which look just like the ones commonly associated with nuclear plants, whereas there are nuclear plants that don't have cooling towers. Notably, both the wrecked Chernobyl and Fukushima plants don't have them (Chernobyl has an unfinished cooling tower intended for unfinished additional reactors): Chernobyl used cooling ponds instead of towers, and Fukushima was cooled by the whole Sea of Japan. Since the cooling towers are open on the top, placing the reactor inside would expose it to the open air, which would obviously be a bad idea.

Idea 2: Nuke-grenade- HO!
 * 1) On the subject of critical mass, while both low-yield nukes and still-bulky "suitcase" nukes do exist in real life, critical mass means that there is an absolute lower limit on the size, weight, and yield of fission-based nuclear weapons.
 * 2) * On the other hand, there are some exotic transuranic elements such as curium and californium, which have much smaller critical mass. You can even make an atomic grenade (very awesome and very impractical) with these elements.
 * 3) * "Critical mass" is a misleading term. Whether a sample of fissile material will produce an uncontrolled chain reaction is dependent on (roughly) the ratio of of mass to surface area. If the ratio is too low (too much surface area) neutrons escape without causing further fission. If it's above the critical ratio, then of the three neutrons produced by each fission, on average >1 will cause another fission (meaning that the rate of reactions will grow). The oft quoted "critical mass" is the critical mass of a sphere of the material at a given density. It's possible to detonate a bomb with less than the "critical mass" of material -- typically by compressing the core with an imploding shockwave.
 * 4) ** The use of reflectors also helps lower critical mass (though the reflector must not be a good moderator, else the bomb will fizzle out due to inability to maintain criticality long enough).
 * 5) Since All Nuclear Explosions Are The Deadliest Mushroom, a nuke will always make a mushroom cloud no matter how small it is, even in vacuum. This is sometimes played for humor. Similarly, mushroom clouds are only created by nuclear weapons, rather than any sufficiently large explosion.
 * 6) * Typically, the size and duration of the fireball and mushroom cloud will also have no real relation to how powerful the weapon is supposed to be.
 * 7) * Also, a nuclear explosion in a visual medium will often produce a series of vertical lines of smoke. These are copied from nuclear tests, but are not actually anything to do with the explosion; they're trails from rockets fired to give a visible indication of the shockwave.
 * 8) In a variant of Space Is Noisy, in a manner also frequently applied to lightning and conventional explosions, even when a nuclear explosion is accurately depicted visually (dazzling flash of light, followed by a rising mushroom cloud and shock waves racing outwards across the ground destroying everything that is not already on fire), frequently it will be heard to produce a deafening roar from the outset, long before the shock wave reaches the camera. Since the shock wave travels somewhat faster than the speed of ordinary sound, the initial flash and subsequent fiery visuals should actually be silent until the wavefront hits, save for the damage caused by the blast's radiation. For any observer sitting far enough away from the explosion to stand a chance of surviving it, this delay should be quite noticeable. Even documentaries have been known to get this wrong (e.g. Space Race).

Idea 3: Fission = Fusion
 * 1) Since fusion and fission-based technology are both atomic, nuclear fusion is depicted as the same as but more than nuclear fission. Plutonium is usually similarly depicted in relation to Uranium.
 * 2) * The existence of fusion-assisted nuclear weaponry is simply not acknowledged. All nuclear weapons, even those in the multimegaton range, run entirely off of fission. Typically, if a "fusion bomb" is talked about, it will imply that the device is extremely futuristic.
 * 3) ** Actually, the hydrogen bomb or "H-Bomb" is a fission-ignited fusion reaction, or a "fission-fusion" bomb. Due to the high initiation temperature required for the fusion reaction to take place, this is known as a "thermo-nuclear" rather than a nuclear device. The term thermonuclear, while often applied to all fission weapons, correctly refers only to the fission-fusion or h-bomb type weapon.
 * 4) *** And further actually, most fission-fusion weapons use a cladding of Uranium 238, which will absorb most of the massive number of 'unused' fusion neutrons and then fission; the bomb is now a 'fission-fusion-fission' bomb. Without that U-238 cladding, the neutrons spray out at high speed, irradiating the near area, and you have what the US called an 'Enhanced Radiation Reduced Blast' weapon -- also known as the "Neutron Bomb".
 * 5) ** There are basically two main types of fusion bombs: the American Teller-Ulam type (also known as the "Sakharov's Third Idea"), and the Soviet Sakharov type, also called "the layer cake". The Teller-Ulam bomb consists of a fission starter charge (often called the primary), a lithium deuteride fusion fuel block (often with the additional neutron source) next to it, clad by the U-238 "pusher" or "tamper" (the whole assembly usually dubbed the secondary), and the shaped heavy metal case. When activated, the primary emits a lot of hard X-rays that are reflected from the case to the secondary, fissioning the tamper, whose explosion compresses and activates the fuel. Sakharov-type bomb has the starter completely surrounded by the fuel and the U-238 case, and the starter is optimized to emit mostly neutrons. When activated the neutrons are absorbed by the case, which then starts to fission, and the heat and radiation from the exploding case compresses and activates the fuel. It is called "layer cake" because layers of Lithium and Uranium could be repeated, increasing the device's output.
 * 6) *** "All modern warheads use the Teller-Ulam system, as the "Layer cake" design was rather inefficient, but it let the Soviet scientists to create an upgrade of the American design, where the additional fission-fusion stages are added to the device, thus making it of theoretically unlimited power. The most powerful thermonuclear device ever detonated, the "Tsar Bomba", was reportedly a three-stage device employed in a two-an-a-half staged configuration, with the tamper of the tertiary made of lead and not the U-238 to reduce the fallout. With the uranium tamper the bomb's projected output was 101.5 megatons, lead tamper reduced it to just ~50 Mt.
 * 7) * Fusion power tends to be depicted as operating in exactly the same way as nuclear power; while the reactor set / prop might look futuristic, expect talk of chain reactions and meltdowns in relation to a fusion plant, even though neither term could possibly be applied to any practical nuclear fusion plant.
 * 8) * Alternately, fusion may be shown as a perfect, clean energy source that generates limitless energy from minuscule amounts of water. Not so in real life. Most proposed fusion reactions generate lots of neutrons, which in turn create radioactivity aplenty. Some possible fusion reactions are aneutronic, mostly or entirely avoiding this problem, but those produce less energy and are technically more challenging to achieve, as if making a viable fusion power plant of any kind weren't hard enough.

Idea 4: I Can Touch Radiation!
 * 1) All nuclear technology and material glows. Most often a Sickly Green Glow. It's usually fatal or at least extremely dangerous just to be in the same room as it, regardless of whether it actually would be or not.
 * 2) * Most radioactive materials don't glow at all. Swimming pool reactors have a characteristic blue glow that's actually Cherenkov radiation -- pretty, but not caused by the radioactivity itself. Some intensely radioactive substances like actinium, cesium-137, and pure radium metal itself (in large enough quantities), actually do glow (technically, self-fluoresce) by their own radioactivity and are generally not healthy to be in the same room with. However, even those are faint enough that you can only see the glow in the dark.
 * 3) * Most radioactive elements are greyish, not green or blue. The most common (non-metallic) color of nuclear material would be from one of the first steps in uranium refinement; yellowcake.
 * 4) * The "sickly green glow" idea probably came from the greenish color of the old glow-in-the-dark radium dial wristwatches. Even in this case, though, it isn't the radium that's glowing. The hands and face are painted with a mixture of radium and zinc sulfide; the latter phosphoresces when struck by the high-energy charged particles emitted as the former undergoes radioactive decay.
 * 5) * Another source of this idea is probably the "uranium glass", a colored glass very popular in the early 20th century. Its actual color and transparency varies from straw to grass-green, and from slightly dusty to completely opaque, but it invariably glows a solid yellow-green under the UV light.
 * 6) Any amount of radiation renders an area a physically unapproachable deathtrap for thousands of years. Radiation in videogames might approach lava in terms of lethality (well, assuming that we're talking about real-world lava rather than video-game lava), or even be used as an ersatz Insurmountable Waist-Height Fence to define the edge of a stage.
 * 7) * Anything this insanely radioactive would be decaying so rapidly it wouldn't actually be the same isotope for more than a few minutes. That's what radioactivity means.
 * 8) * It's perfectly possible to walk around in the Chernobyl Exclusion Zone without dropping dead in seconds or growing a third arm. In the entire 30-kilometer Zone dangerous radiation is limited to two "hot spots" with a total area of 2000 square meters, and 'dangerous' means 'a picnic in this place might result in some radiation poisoning'. The Zone's become an accidental nature reserve. Not everything is roses, though: animals in the area have approximately half their normal lifespan, and birth defects are common.
 * 9) * People live in Hiroshima and Nagasaki, despite the best efforts of a pair of horribly primitive and inefficient strategic nuclear weapons. Weapons that would have left a much larger and more concentrated amount of radioactive fallout than more efficient weapons. This is helped by a benefit of an air burst - if the fireball doesn't touch the surface, fallout is extremely small. If it does touch the surface, though, it's irradiating and vaporizing tons of dirt/water which then go up in smoke... and later come down. Somewhere.
 * 10) Walking hand in hand with Artistic License: Biology, instant, horrible, in-generation mutations caused by exposure to radiation. Actually, living organisms simply do not work that way. For starters, where radiation is supposed to "alter" (e.g. damage) DNA/RNA, it would have to introduce pretty much the same very specific change in billions, per body cell count, of random events hitting that DNA. Then, as a functioning body actually has far more regulating systems active, it should somehow alter all of them in precisely the same manner, so we do not get an old, boring Real Life set of radiation symptoms like body systems fighting in an attempt to fix each other. And not the least, the amount of radiation doing all that should somehow fail at destroying/damaging every other body chemical but DNA (rendering the whole organism inoperable) or simply frying the subject in the process.
 * 11) People in flash radius not getting burned or otherwise harmed. The flash is one of the most immediately fatal parts of a nuclear blast - if you're close enough to see the light as anything but a distant light on the horizon, you're close enough that your clothes will likely ignite (as will anything flammable around you) and your skin will be burned (depending on distance, anything from vaporization into a shadow against whatever standing surface is nearby to, at longer ranges, the nastiest "sunburn" possible) and you will be blinded if you were looking in its direction.

See also A Nuclear Error for policy-related gaffes involving atomic weapons. This trope is frequently invoked by writers who Did Not Do the Research. A good portion of these have fallen victim to The Coconut Effect.

Anime

 * Amazingly enough, Mobile Suit Gundam averted this: a nuke is launched in one episode, and is then sliced apart by the eponymous Gundams beam saber. Slicing the nuke does not cause it to explode, but fall to pieces harmlessly. How averted this is is debatable, as Amuro is shown he has to slice the missile apart in a certain way to keep it from exploding. Draw your own conclusions.
 * Sadly, later series are more inaccurate. Both Mobile Suit Gundam 0083: Stardust Memory and Chars Counterattack also prominently featured nukes... which did not behave much like actual nukes would (most horribly: the Physalis Gundam's nuclear bazooka looks like it fires some sort of beam rather than a projectile).
 * The GP-02's atomic bazooka doesn't seem to be a conventional nuclear missile launcher, as instead of a missile flying out of the shaft, an intense beam of energy emerges. This suggests that the bazooka is actually a casaba howitzer, a directed energy weapon that utilizes a nuclear-shaped charge to generate a high-energy gamma ray laser and is essentially a hypothetical real-life Wave Motion Gun. However, they still fail in that in order to make a casaba howitzer that small without blowing up the GP-02 in the process, it would have to be made of a material much MUCH stronger than anything currently known to man, and since mobile suits of all makes and models are getting torn apart by simple energy and kinetic weapons, this probably isn't the case.
 * Gundam Seed has ZAFT remove nukes from the equation of war with the N-Jammer, a device that completely cancels nuclear reactions in its radius... somehow. Then N-Jammer Canceller technology is discovered and they go back to launching nukes. ZAFT's next countermeasure is the Neutron Stampeder, which somehow prematurely detonates the warheads before they're launched.
 * In the Bubblegum Crisis, the final episode has a runnaway robotic tunnel digging machine, uh, digging a tunnel though an active fusion reactor. The secondary police characters were alternating between ranting against and calmly accepting the imminent vaporizing of Mega-Tokyo. To be fair, it was digging very fast, almost a foot per minute.

Comics
""No one there is a physicist. But they still know what happens when you puncture a nuclear reactor.""
 * Justice League #3 (1987) features the "cooling tower = reactor building" misconception.
 * As does The Amazing Spider-Man #329: Spider-Man (who has the powers of Captain Universe at this point) fights the Tri-Sentinel, who attacks a nuclear power plant. During their fight, the Tri-Sentinel smacks the cooling tower, to which Spidey comments: "Oh, no! He's cracked a containment tower!"
 * In Identity Crisis, Firestorm the Nuclear Man, mortally wounded after being impaled through the chest with the Shining Knight's magical sword by the Shadow Thief, detonates like an atomic bomb a short while later. The omniscient narrator, Green Arrow, comments:

""Well, I am a physicist, and the answer to what happens when you puncture a nuclear reactor is: Pretty much nothing. [...] In no case would you get, as Identity Crisis's narrator seems to think is self-evident, a nuclear explosion. Worst case, you get an explosion of radioactive material (not unlike a 'dirty bomb,') but you're not going to get a Fat Man-type explosion.""
 * To which reviewer Greg Morrow of the comic book blog "Howling Curmudgeons" had this to say:


 * Deconstructed in, Watchmen. The Big Bad uses this trope to convince an ignorant public that Dr. Manhattan is a walking radioactive cancer-machine.
 * In The Butter Battle Book, the Bitsy Big-Boy Boomeroo appears to be the size of a thimble, yet has enough destructive potential to send the Yooks racing for the fallout shelters.
 * The death of Locke in the Archie Comics Sonic the Hedgehog story "Mobius: 25 Years Later". Let's see, why is Locke dying? Because he contracted cancer. How did he contract cancer? Because of a lifetime of absorbing Master Emerald radiation interacting badly with his altered DNA. Why is his DNA altered, he experimented on himself to give his then-unborn son Chaos-fueled superpowers. See the problem? The same genes that end up killing him through enhanced radiation sickness are now in Knuckles. Oh, and just to add further insult to this, Locke gave Knuckles' egg a big ol' dose of Master Emerald radiation soon after it was laid. How Knuckles didn't hatch into a stillborn tumor baby, while his dad ended up dying from cancer, despite having the same combination of altered genes and radiation, is anyone's guess.

Fan Works

 * Peter Chimera's Half-Life fanfic Quarter-Life: Halfway to Destruction. Being a Troll Fic, it does not have the usual errors but instead makes up new ones. Examples:
 * An isotope being so "vollatile" [sic] that it doesn't have a half-life, but a "quarter-life".
 * The "quarter-life" of a radioactive material would be the time taken for the radioactivity of a material to drop to a quarter of its original value; this would be precisely twice the half-life of a material.
 * Said isotope "hit[ting] the quarter-life" causing a meltdown, which makes the room "slowly become vaporize," causing a scientist to be "blowed to smitheroons."
 * And finally, the isotope "goes off harmless" when plunged into the ocean.
 * Light and Dark The Adventures of Dark Yagami keeps returning to this one. A nuclear bomb is no more powerful than a small pipe bomb ("the nuclear bom went off like a bom") -- the worst of the damage is a scratch in Light's dad's car -- but covers the area in "radiactiv" (which fatally irradiates "Yotsuba" but leaves everyone else unharmed). Later, nuclear missiles are used as pens, and even later than that, putting "nuclears" in a normal explosion makes it magic, letting it chase our 'hero'.
 * The Life After Death Trilogy, a post-Spider Man 2 fanfic starring Doc Ock, deals with two examples of nuclear physics. First is Dr. Octavius's infamous experimental fusion reactor, and more in line with this trope are the four plutonium batteries he uses to power the tentacles. At one point Octavius mentions that he's rigged a failsafe in them that will deliberately overload the batteries in the event of his death as a way to keep the tentacles from falling into anyone else's hands, essentially making a quartet of small nuclear bombs. Vindictive as he might be, this trope does get averted in that Octavius knows full well that nuclear reactor =/= nuclear bomb and the damage his little batteries would inflict is nowhere near the annihilation of half of Washington DC he threatens.

Films -- Animation

 * In Animatrix, the scenes that explain how the machine city went to war with humanity has a part that involves humans nuking the shit out of their city. And the narrator says that it doesn't work because the machines "aren't affected by radiation." Ouch. Apparently nukes in The Future have no blastwave, and robots of The Future are immune to heat and the Electro Magnetic Pulse that comes from a nuclear blast. Considering they use EMP as their main weapon against the machines in the movies, it makes even less sense.
 * The Martian nuclear reactors in Pinocchio in Outer Space. They go supercritical and explode like an atom bomb (complete with mushroom cloud) because of sand blowing into their underground complex.
 * Zig-zagged in The Iron Giant: a nuclear missile is detonated in the upper atmosphere, resulting in a fireball and not a mushroom cloud, but played straight in that punching the nuke would not have caused it to detonate.
 * If the Iron Giant had been a bit more familiar with Earthling technology, he might have realized that it would be possible to cripple the missile from a safe distance with a long-range weapon like a laser -- instead of ramming into the missile head-first in a self-sacrificing kamikaze attack. But, obviously, that would've been emotionally anticlimactic.

Films -- Live Action

 * Use of stock footage from nuclear tests is very common in B-movies; these will typically include vertical smoke lines, even when the weapon is supposed to be a battlefield deployment.
 * For those who don't know, those smoke lines are from rockets that were launched during nuclear tests to measure the path of the shock front.
 * The movie Testament featured a "harmless flash." As noted above, if you are close enough to see the flash in such a way, you're likely being burned up in it. Nuclear flashes are not just harmless pretty or scary light - they are intense heat.
 * In the cyberpunk action film Babylon A.D. a radiation-shielded train passes over a bridge built across a massive crater blasted by a nuclear power plant. While a cool scene, apart from the "reactors blow up" fallacy, it also raises the question of the difficulties of building a bridge in such a highly-radioactive area (not to mention the expense of creating shielded trains) versus just building a detour.
 * In The Core, the good guys suddenly realize they need to up the yield of a nuke by 20% if they want to save the world. How do they accomplish this? By taking a plutonium bar from the Cool Starship's power generator and placing it right next to the bomb. Stacking anything "nuclear" next to a bomb will not improve the bomb's yield.
 * In The Swarm, a horde of killer bees gets into a nuclear power plant. This somehow causes the plant to go critical and go up in a gigantic explosion (within seconds!). Without killing the bees.
 * In an aversion of the trope, in The Peacemaker Nicole Kidman successfully stops an atomic explosion by distorting a piece of the explosive jacket surrounding the plutonium core, resulting in a small (if a bit dirty) conventional explosion because it wasn't shaped properly. This is exactly right.
 * At the beginning of the movie, a train carrying nuclear weapons explodes when it hits another train head on. The heroes point out that shouldn't happen, as modern warheads have numerous safeties. As one character puts it: "You can fire a pistol right at the warhead and it wouldn't go off." In fact, the bad guys rigged a nuke still on the train to blow.
 * The movie also correctly illustrates that most thermonuclear weapons consist of a primary fission charge and a secondary fusion fuel package. The Big Bad removes the latter to make the weapon light enough to carry. (Though the elements are significantly larger and heavier in real life.)
 * In the James Bond movies:
 * The World Is Not Enough: The Big Bad gets hold of the plutonium sphere from a bomb, forms it into a rod, and tries to insert it into the reactor of a submarine and cause a meltdown.

Not to mention that Bond and the Big Bad handle the plutonium bar with their bare hands. A rod of Pu that size would weigh at least 50 pounds, which is big enough to be a critical mass. It would be exceptionally hot to the touch, and also would be emitting lots of neutron radiation.
 * The reactor of the movie's 1967-vintage nuclear sub had fuel assemblies (that plutonium rod) which could be manually inserted and removed. That's not how a Russian sub reactor is designed (though it is closer to certain heavy water power reactors.) To refuel the sub, they first need to shut down the reactor for 90 days so the fuel is not too hot from a radioactive and thermal standpoint. Then they cut open part of the sub's outside hull to remove the fuel assemblies. Big job, needed once every 5 to 10 years. The bullet stuck in the Big Bad's brain would have killed him by then and the audience would be quite bored.
 * Tomorrow Never Dies averts this in the end. A nuclear missile is going to be fired at Bejing in less than a minute. Since James Bond doesn't have enough time to delicately disarm, he just attaches some explosives to the tail end of the missile so when the missile ignites to lift off, the flames detonate the explosives, safely blowing the missile to hell.
 * Averted and played straight in The China Syndrome.
 * Averted in that the reactor incident shown toward the beginning of the film is a fairly realistic failure mode for a nuclear reactor from the period. (The partial meltdown at Three Mile Island a few days after the film's release was remarkably similar.)
 * Played straight in that the description of the possible effects of a reactor meltdown (including the Title Drop) by a so-called expert is basically a thinly veiled anti-nuclear screed.
 * Terror from the Year 5000 has an archeologist use carbon-14 dating to determine that a metal statue came from the future. And when he and another guy hold a Geiger counter over the statue, they are shocked to learn that it's incredibly radioactive. Seeing as carbon-14 is a radioactive isotope, you'd think they would have noticed this earlier...
 * Also you can't use C14 dating on non organic substances(sometimes works on pottery because straw was used to reinforce unfired pots). C14 is built up in living organisms then decays after the organism dies, so assuming the statue was organic its age would be dated from its creation regardless of time travel. Uranium dating would have avoided all these problems.
 * The second Spider-Man movie features a extremely silly depiction of fusion power so Doc Ock's tentacles take control of his body (they're to manipulate the fusions!). Highlights include Doc Ock saying there's only 25 pounds of Tritium in the world, a deeply ridiculous open-sided reactor, and dropping an object established to be a miniature sun into a river where it, um, goes out harmlessly. Because fusion plasma does that.
 * Prior to being quenched by the river, the miniature sun is shown acting as a tremendously powerful magnet, pulling in girders of the building it is contained in and instantly consuming them in its plasma. However, iron requires rather than produces energy by fusion. In contrast, water, being composed of light elements, is more likely to fuel a fusion process. So something that would have instantly snuffed out the miniature sun is depicted as making it more powerful, while something that would have made it more powerful makes it fizzle.
 * Back to The Future featured a minuscule plutonium powered fission reactor that barely altered the shaped of the famous DeLorean time machine, had a 1.21 Gigawatt output (greater than many full-sized nuclear power stations), and expended an entire fuel rod in an instant. Later it's apparently fitted with a fusion reactor the size of a coffee grinder that runs on household waste.
 * In Aliens the colony's nuclear fusion reactor has been damaged. Of course this means that it's going to go off like Tsar Bomba in a matter of hours.
 * However, it's mostly averted in the first movie-- when the Nostromo's engines overload, the blast appears as a large circle of light in space, and there is no sound until the shockwave hits the still-too-close escape shuttle.
 * Discussed and averted in Under Siege when Steven Seagal's character is preparing to fire on the sub with the stolen warheads and the character Jordan Tate asks "Won't the bombs detonate?" and he tells her "It doesn't work that way, they will just sink".
 * Averted in John Woo's Broken Arrow. After the (deliberately engineered) crash of a Stealth bomber carrying nuclear missiles, it is correctly stated that the warheads cannot be detonated by burning jet fuel.
 * Later the villian tells his team not to shoot at the warheads. He knows that they will not detonate, but is worried that the arming system will be damaged.
 * Hilariously parodied in Young Einstein, when Einstein attempts to add bubbles to beer by splitting the beer atom... with a chisel. Eventually he succeeds, and an exterior shot lets us watch his shack explode.
 * Let's not forget he goes on to top this by stopping a runaway nuclear reaction by hooking up an electric guitar to the reactor and playing it at insanely high decibels to bleed off the energy. "IT'S ALL RIGHT MARY! ... THEY'RE ONLY ELECTRONS!"
 * In a surprising aversion (considering the movie involves angels, demons, psychics and the son of Satan), the director of Constantine had seen old videos of dummy towns in nuclear test footage, and so designed Hell to look like "A continuous nuclear explosion that could never have a shockwave."
 * In Superman IV: The Quest For Peace, Lex Luthor says that nuclear power mixed with genetic material will create a being more powerful than Superman.
 * In the same movie, Superman drops Nuclear Man into the cooling tower of a nuclear power plant... and he somehow ends up inside the reactor (which should be located in an entirely different building). Which somehow ends up destroying Nuclear Man.
 * In K19: The Widowmaker, after the K-19's reactor suffer a coolant leak, the reactor officer, which just graduated from the academy, explains that the pressure will continue to build up until it reaches critical, at which point he explains he has no idea what's gonna happen but speculates that a nuclear explosion would happen with the melt down and "cook off" the nuclear warheads they're carrying.
 * Another surprising aversion in the comedy/action flick True Lies, when Marine Harriers attack a trio of nuke-carrying trucks. One of them asks for confirmation that the missiles won't set off the nukes, and Schwarzenegger's character assures them that they won't. His expression to his partner after he says this, however, indicates he isn't as sure of this as he sounds. Since he is telling them to go ahead, he probably is aware that even if it is possible, it's extremely unlikely, and a chance well worth taking, weighed against the potential harm of the trucks getting away.

Literature
"Gaudior: "You know some of the possibilities if your planet is blown up." Charles Wallace: "It just might throw off the balance of things, so that the sun would burst into a supernova.""
 * Averted in the first of Harry Turtledove's Worldwar novels, when the Germans use the the 80-cm Dora railway artillery to destroy two alien ships, one of which holds the Race's nukes. The nukes' detonators go off, but no nuclear explosions occur, as the bombs are deformed by the ship exploding. However, the explosion does spread radioactive material over a large area.
 * Averted in The Dark Tower, at least a little. When Eddie Dean sees the creatures in the Waste Lands and exclaims that a nuclear war took place here, Blaine corrects him and states that it was something far worse.
 * Roald Dahl's 1948 novel Sometimes Never: A Fable for Supermen is the first science-fiction to involve several nuclear bombs. But it averts this, being surprisingly accurate and graphic. It has two third-shot accounts by witnesses of nuclear blasts. By the way, every named protagonist is killed by the same nuke.
 * Jack Ryan:
 * In The Sum of All Fears, the workings of the nuclear device were intentionally altered by the author in an attempt to limit the usefulness towards making Real Life nuclear weapons, as noted in the afterword.
 * In his earlier novel (but not the film) The Hunt for Red October, a Soviet submarine racing to intercept the Red October suffers a catastrophic reactor accident. In a realistic aversion, the reactor core doesn't explode, but simply melts through the reactor vessel and the ship's hull, causing it to sink.
 * Lester Del Rey' s 1956 novel Nerves features a nuclear reactor where nuclear isotope production is discussed in terms that sound considerably more like chemistry than nuclear physics.
 * Robert Heinlein:
 * Averted in Heinlein's short story "The Long Watch". The protagonist prevents a nuclear attack on the Earth by military forces on the Moon by taking the bombs (which are Little Boy style "gun barrel" devices, rather than the Fat Man type of "implosion device" more often featured in fiction) apart and smashing their plutonium cores with a hammer., which is again realistic (although the absence of is not).
 * It isn't very realistic, though. Gun-type design is in fact completely unworkable for plutonium bombs, because the fissile Pu-239 isotope is always contaminated by an even more fissile and extremely hard to get rid of Pu-240 isotope, which would initiate a chain reaction long before the two cores are sufficiently joined, thus making the bomb to fizzle. To avoid this either the cores should be joined at the speeds in the kilometers per second range, or Pu-240 completely removed from them, both variants technically impossible. That's actually why all plutonium devices in use are implosion-type.
 * The story was written in 1949, back when pretty much all the basic facts about nuclear weapons design were still classified at 'kill yourself before reading' levels. I'm quite frankly amazed he got as many details correct as he did.
 * Heinlein sets up a blatant type 1 error in "Blowups Happen," a story where power is generated at a nuclear plant where tons of plutonium are kept just below critical mass. Any failure is going to be catastrophic, and the operators know it. The author gets a pass, though, because he wrote this in 1940, (two) years before anyone (Enrico Fermi, for that matter) had built a nuclear reactor.
 * Interestingly, the reactor in this story actually is based on real life design proposals, which would allegedly be more energy efficient and produce less radioactive pollution than models currently in use. They nonetheless never went beyond the planning stages due to the aforementioned necessarily catastrophic nature of any failures that would occur, though some allegedly safer designs using similar features are currently being floated.
 * Number 4 is subverted in Ian Fleming's James Bond novel Moonraker; the nuclear explosion is.
 * Lampshaded in Alan Dean Foster's Spellsinger novel Paths of the Perambulator, where Jon-Tom creates a miniature mushroom cloud using magic and then muses that nothing is impossible in a magical world.
 * Spoofed in David Langford and John Grant's parody disaster novel Earthdoom. Two men lost on the London Underground are, for different reasons, both carrying quantities of radioactive material. When one of them is discovered and forced to stand at the end of his Tube train by a conductor, he - being a newspaper science correspondent - delivers an angry lecture about how this stuff can't just explode at the drop of hat, and even if this train were to run into a brick wall right now, nothing would happen unless there was a sufficient amount of material on the other side in just the right position... At that point the train runs into a brick wall. Guess who's standing on the other side.
 * In the Foundation series, the first two stories feature nuclear stations which blow up due to bad repairs.. or just some idiot messing with the controls. This was, mind you, written in the early Forties. Later editions changed it to radiation leaks.
 * Spectacularly averted and/or subverted in Isaac Asimov's The Gods Themselves when a radio-chemist discovers a radioactive element that cannot possibly exist under the known laws of physics - it turns out to be from another universe where the laws of physics are sufficiently different that it can exist there!
 * Averted and lampshaded in Murray Leinster's novella Second Landing. The protagonist needs to disarm a nuclear bomb extremely quickly, and does so by shooting it with a bazooka. The bazooka blast renders the bomb unworkable, but does not detonate it, since that requires proper sequential detonation of the shaped charges surrounding the nuclear material.
 * Averted in the Halo Expanded Universe. In one of the books, the Spartans actually use nuclear bombs for shields, as they're bulletproof, because that gives them a stronger explosion.
 * In another one, the Spartan Blue Team laughs at the Covenant's lack of understanding of nuclear weapons, as they watch a pack of Brutes wrestle the bombs into Styrofoam containers.
 * Of course, if so much as a single tiny dent or ding reached the bomb's fuel, it would "fizzle" on detonation...
 * Halo: Ghosts of Onyx actually had the Spartans fire grenades into an elevator with the UNSC's "older" nuclear warheads, since they're "basically paperweights" without the arming codes. They're bemused by how their alien foes treat the warheads with kid gloves.
 * Averted in The Atrocity Archives. A nuclear bomb is set and primed to blow an alternate reality to hell, but a member of the team realizes that's the last thing they want, as the bomb's energy will give the monster inhabiting the universe enough power to come through to ours. So, he manages to defuse the bomb by popping the caps without triggering the plutonium.
 * In A Swiftly Tilting Planet, one of the sequels to A Wrinkle in Time, the following exchange takes place when talking about nuclear war.


 * Keep in mind that in the Time series, stars are living beings that have been known to commit suicide or take self-sacrificial actions, and that parts of a living being can be independently sentient. It's not unreasonable, given the bizzare nature of reality in the series, to assume the loss of the only celestial body in the local area that is capable of supporting matter-life would unduly affect Sól.
 * In John Ringo's Legacy of the Aldenata series, specifically in novel Hell's Faire, there is a new nuclear-like weapon. It is described as having its primary radioactive isotope scattered in the area of effect, carbon-13, as having a very fast half-life. The trouble is, carbon-13 has no half-life at all, because it is a stable isotope. (Carbon-14, on the other hand, is radioactive, if only very slightly; its half-life is on the order of five thousand years. Such a long half-life implies a very low decay rate, and consequently a complete unsuitability for use in any kind of 'dirty bomb' application.)
 * In Joe Haldeman's The Forever War, frequent reference is made to nuclear weapons with yields in the microton range. One microton is just one gram, or approximately three one-hundredths of an ounce -- or, in other words, since we're talking about yields in terms of TNT-equivalent, barely a firecracker's worth of bang, and that's if we're being generous. Now, in theory, it would be possible to produce a nuclear explosion out of such a tiny mass of fissile material, by increasing its density enough to drive it supercritical -- trouble is, there's no point; The Forever War is set in the future, and even today we know how to make chemical-explosive rounds which produce quite a bit more than a firecracker's worth of bang.
 * H. G. Wells's novel The World Set Free (1914) features what may be the first ever appearance of atomic explosives anywhere, but considering that it was written at the tail-end of the Victorian Era, the physics are quite dodgy. Extrapolating from the idea of radioactive decay as something with a tremendous amount of energy releasing it over a long period of time, Wells' nukes work by somehow speeding up this process. Instead of releasing all of its nuclear energy in an instantaneous, massive explosion, the bomb speeds up radioactive decay to the point where you have a huge fireball that hangs around for several days before dying down.
 * Leviathan Wakes plays #1 completely straight. If anything happens to a ship's fusion plant, it goes off like a thermonuclear bomb.

Live Action TV

 * The 1939 serial The Phantom Creeps posits that a radiation poisoning antidote can be made by mixing in the original radioactive substance, a radioactivity measuring device can measure the radioactivity of an object several rooms away assuming the whole area isn't irradiated, and if the mad scientist ever completes his doomsday weapon it will be more powerful than dynamite.
 * A lot of people have been criticizing Lost, without a lot of cause, as Lost got it mostly right. On Lost, the 'gun-type' plutonium fusion core of a hydrogen fission bomb was removed from a 1950-era hydrogen bomb by an Iraqi military officer with electronics experience, using the notes of a physicist, both from 2004.

They averted #1 specifically having it rigged to explode on impact, with the implication that it would not normally. .

Also, the guy carrying it, at one point, was threatened with a gun, and he points out he's carrying a nuclear device and you shouldn't shoot him...but he was probably just using the trope to keep from getting shot.

It was, however, somewhat lighter and smaller than it should have been. Hydrogen bombs of the 1950s weighed a good 15,000 pounds. If you could get the trigger out and turn it into a backpack bomb, the trigger alone for a H-bomb required at least 60 kg of pure U-235 to create the fission explosion required to set off the bomb, even before you look at the surrounding 1950s-era mechanics used to set off the explosion. Also, people tended to call it a "hydrogen bomb" even when they're talking about the trigger that was removed.

The biggest problem with Lost was that they were talking about the core of the bomb. The core produces the fusion reaction, which is triggered by the fission reaction happening around it, which is triggered by an external layer of high explosives. There's a reason that people make big nuclear bombs that have to be dropped from planes instead of just little remote-control-size assemblies.
 * In the pilot miniseries of the new Battlestar Galactica, there is a mushroom cloud, implied to be a large nuclear strike, less than one mile from where Boomer and Helo are fixing the Raptor. The two are not only alive, but also suffering no ill effects, nor is there any visible damage to the landscape near the mushroom cloud.
 * The show gets points for avoiding number 2.2, depicting detonations as bright flashes or pulses of light.
 * Helo also has to take radiation meds while on Caprica.
 * There's an episode of Lois and Clark where Lex Luthor has built a nuclear power plant and claims that not being able to shut down the reactor once it began its start up sequence was a 'safety feature'.
 * Also, apparently nuclear radiation is enough to destroy the kryptonite traces in Superman's blood but not enough to kill him. This is despite the kryptonite making him weaker than a human.
 * An entire episode of Star Trek: The Next Generation was based on averting number six; Data crash lands on a planet with a pre-industrial society and develops android amnesia, so he doesn't know the metal in the box he's carrying is dangerous, or even what the word "RADIOACTIVE" printed on it means. Thinking it harmless and grateful to the local village for helping him while he suffers his memory loss, he sells the plain-looking, gray pieces of metal to their merchants, who then sell it as jewelry, and people all over the village begin getting sick with radiation poisoning. With no memory of how such things work but with his capability to learn intact, Data spends the rest of the episode investigating the sickness and learning that the nondescript metal actually gives off dangerous, invisible energy. The realism takes a drop near the end when he cures the town with a liquid medicine akin to Rad Away in Fallout.
 * Space: 1999. Nuclear waste stored on the Moon undergoes a chain reaction and detonates. The explosion is strong enough to throw the whole Moon out of the solar system, at a sizeable fraction of light speed.
 * The CSI: Miami episode "Dead Woman Walking" takes the "radiation = lava" trope literally with an iodine-131-contaminated corpse slowly burning up from radiation exposure. Strangely, though, the rest of the episode is quite well researched and gets an impressive number of details right - including the use of real-life spectrometry tools instead of a Magical Computer, and an aversion of Sickly Green Glow with a character even pointing out that "it's not like [the radioactive material] glows or anything".

Music

 * Ultravox, "Dancing With Tears In My Eyes". The lyrics are about The End of the World as We Know It in general, but the video instead involves a town being destroyed by a nuclear power plant meltdown, apparently instantly vaporizing the residents while leaving other objects intact. "REACTOR CORE OVERHEAT, EXPLOSION IMMINENT", etc.

Puppet Shows

 * The Thunderbirds episode "The Mighty Atom": a nuclear reactor goes critical and explodes, rather than overheating and melting down.

Tabletop Games

 * The Gamma World Tabletop RPG adventure "The Legion of Gold". If damaged, a fusion reactor will detonate like an H-bomb.
 * Averted in Paranoia's "The Yellow Clearance Black Box Blues". An old (pre-Whoops) nuclear reactor will eventually melt down, not explode. Lots of other stuff in Paranoia explodes just fine, though, not infrequently in nuclear fashion. They even have nuclear hand grenades, with a blast radius way bigger than the range you can throw them.
 * Steve Jackson's Munchkin started life as a card game, but has also had a set of Core books printed exporting things from the card game into a Dungeons & Dragons setting. One of these is the Plutonium Dragon, which halves in size every 15,000 years (leading to... interesting questions regarding breeding, as it gets smaller, not larger, as it ages) and has a special rule called Meltdown. Basically, if you kill it, then, depending on its age, it might possibly obliterate everything within a five-mile radius.
 * Any implausibilities about nuclear weapons and radiation in Deadlands: Hell on Earth can be easily explained away with one phrase: "supernatural nuclear reactions." Yes, radiation does glow green, but that might only be because everyone expects it to. Yes, there are rules governing the detonation of a "G-Ray Bomb," but only one governing conventional nukes.
 * BattleTech mostly averts these, but flirts with 1 and 3 a little. To wit: BattleMechs and many other vehicles are powered by fusion engines. By the core game rules, damaging those enough will simply cause them to shut down, disabling the unit. So far, so good. However, because some BattleTech fiction, notably novels by Michael Stackpole, featured breached 'Mech reactors spontaneously and dramatically exploding every so often (in fact, "Stackpoling" became fan-speak for exploding reactors). An optional rule allowing for this to happen if desired also exists based strictly on the Rule of Cool (its lack of realism is explicitly noted).
 * A fluff piece in the Tech Manual source book explains away the BattleMech reactor explosions as the effects of air hitting the inside of a very hot reactor vessel combined with ammunition and other volatile components detonating as well. Another in-universe fusion reactor explosion is also shown to be the result of a roof collapse dropping tons of snow upon the reactors liquid sodium cooling system. The narrator noted the reactor was almost an innocent bystander.

Video Games

 * The Half-Life series (ironically enough!), with sickly green radioactive waste that functions as Convection, Schmonvection lava.
 * Starcraft has tactical nukes that give off the token mushroom cloud (even in outer space), despite not being powerful to bring down even one half-decent building.
 * Oh, and if you click enough on a neutral critter, it explodes with the same mushroom cloud...
 * In the backstory, they had much, much bigger nukes. With which they sterilized a planet. Once they realized they could actually, y'know, do that, even the Confederates weren't big enough idiots to keep 'em around. The "nukes" in-game would likely just be big friggin' conventional bombs, called nukes because it sounds badass. (Low damage is more a matter of game balance.)
 * 'Course, Starcraft is just full of these inconsistencies, due to Gameplay and Story Segregation. The mushroom cloud is due to Rule of Cool and The Coconut Effect.
 * Fallout 3 has a Fat Man weapon and atomic cars (fusion-powered cars!) that both go up in cute little radioactive mushroom clouds about the size of an artillery blast when they explode. However, it's justified as the Fallout series is about 1950s perceptions of the general public of how nuclear technology works. Another notable example is the Enclave Oil Rig's nuclear reactor in Fallout 2, which detonates in a massive nuclear explosion after the player causes a meltdown.
 * It is worth mentioning, however, that man-portable weapons capable of firing nuclear projectiles were produced and a nuclear car was at least considered and designed (Ford Nucleon). Fallout also shows the the world as the people in Atomic Age seen it complete with deliberate use of Science Marches On.
 * Fallout 1 has The Glow, a permanently radioactive area due to a reactor getting hit by a missile. The game and its sequel also have some extremely powerful chems - Radaway siphons away radiation in your body harmlessly (although it's implied that the process is complex and unpleasant, rather like performing an improvised dialysis) while Rad-X bolsters your natural resistance in an improbable and unexplained way. Take two and you can walk around in The Glow with no harm at all!
 * Averted/justified in Metal Gear Solid. When Snake reaches the room where the dismantled nuclear warheads are stored, he can't shoot for fear of damaging the nukes -- not because it might cause them to blow up, but because they might breach the radioisotope containers.
 * Naturally, the guards will go all Rambo in that very room if Snake is discovered. They're wearing NBC suits, and Snake isn't (though in the remake, they use airfoil rounds).
 * In the Civilization series, the icon for the Uranium resource looks like glowing green rocks.
 * In Ratchet and Clank, every explosive is nuclear, and produces a mushroom cloud, even though the blasts are about the size of a fairly weak firecracker. Rule of Funny and/or Rule of Cool are definitely in effect here.
 * Sim City games almost avoided this trope -- if your nuclear plant melts down, the surrounding buildings are left undamaged (except for a small risk of fire), but fallout is scattered around the surrounding area, rendering it uninhabitable. In retrospect, they probably should have put a containment dome over those reactors or something. Sim City 4 plays it dead straight though: an exploding nuclear plant creates a huge blue mushroom cloud, a massive crater and a big shockwave that can flatten half your city.
 * The nuclear missile in Shadow Warrior.
 * Nothing ways BFG like a nuclear bazooka
 * The "World's Smallest Nuclear Bomb" in MDK, complete with miniature mushroom cloud (about 6' high) and, showing some attention to detail, a ground shock wave.
 * The Command & Conquer series has many of these:
 * Exploding Nuclear reactors or weapons:
 * One of the Soviet missions in Command & Conquer: Red Alert takes place in a nuclear power plant that the Allies have sabotaged. Your technicians must activate the cooling systems on the reactor before the core melts down. However, if you fail, the game shows a video of an exploding atomic bomb, which is not the same thing at all.
 * In Red Alert: The Aftermath and Red Alert 2 the Demolition Truck produces a nuclear explosion when destroyed. While they may have designed it to do this you think they would wait to arm it until they got it away from their own base. In Red Alert 2 destroying the Soviet nuclear reactor causes a large explosion. The Command & Conquer: Generals series includes the Chinese, with nuclear superweapons, a smaller war-head siege weapon, and a forest of nuclear power plants that can be (you guessed it) set off in a chain reaction of tiny atomic explosions. If the players purchase the nuclear tank upgrade to make their tanks move faster their tanks will explode if destroyed.
 * Honorable mention: in Red Alert 3, the Soviet Superreactor will cause a massive explosion when destroyed, which can destroy most units if they're too close - despite nukes canonically not having been invented yet. (What do the plants run on? "Chemicals.")
 * In the Chinese campaign in Generals the GLA use a Chinese nuclear missile as a stand still bomb.
 * Weak Nukes
 * In a few games in the series (notably the first Red Alert), nuclear missiles could barely destroy a tent when dropped right on it. Later games (and even the original Command & Conquer) had much more powerful nukes (Nod's nuke in Command And Conquer 3 can punch a pretty good hole in a base).
 * Speaking of C&C3, it features a Nod mission where the player must steal several nuclear warheads with a pretty pathetic force guarding them. If the player attacks the trucks the warheads detonate into a mushroom cloud.
 * For the first Red Alert, its somewhat true - however that is only for multiplayer, where a nuclear weapon hit the square targeted, then two squares out in a ring around the target. In short, some units standing next to a nuclear explosion could take no damage at all. In Singleplayer, if a nuke is fired, it does not only cause the white flash, but vaporize everything in the blast radius. Tiberian Dawn was similar, in that a missile launched from the Temple would obliterate anything.
 * The Apocalypse tank in Red Alert 2 can be upgraded with experience to fire nuclear ammunition, causing small mushroom clouds about the size of a tank but not necessarily killing anything in the vicinity. Infantry are notorious for surviving direct hits from tank shells. This is about as realistic as Tesla bombs dropped from the veteran Kirov airship that produce an electrical explosion. Oh wait, this is Red Alert we are talkinga about here, the universe where reality takes a backseat to coolness.
 * Maniac Mansion may end badly with the nuclear reactor in the mansion's basement melting down -- which causes a mushroom cloud explosion obliterating everything in a five mile radius.
 * Averted somewhat in Mega-Lo-Mania (Tyrants: Fight Through Time) a nuke will destroy a sector unless you have nuclear defence turrets to shoot it down, the sector then becomes uninhabitable.
 * Very nicely averted in Hammer and Sickle when, in the next to last mission, the main character says something like "When we find the nuke, just shoot it, or throw grenades at it." When the other characters complain that it's going to blow, he tells them getting a nuke to go off is a very difficult process, and that it's very unlikely that the bad guys ship it around armed and ready to go off. You get a nice dose of radiation poisoning that quite quickly drains your hit points though.
 * "Fallout" is used as a substitute for walls in the Chernobyl stage of Call of Duty 4: Modern Warfare.
 * Most games of Doom's era tended to have open pools of radioactive waste as a type of hurt floor, typically shown as being slightly less dangerous than lava.
 * The Metroid Prime games feature Phazon, a Phlebotinum substance so ridiculously radioactive that it can kill someone wearing a sealed, armoured spacesuit in less than a minute. It's apparently also stable. Erm...
 * It's apparently also organic, biological and sentient making it's "radiation" more like some kind of unique bioenergy field people can siphon off.
 * Crysis features several variants of battlefield nuclear weapon; all produce the "columns of smoke" effect that would only normally be seen in a nuclear test.
 * Touhou Project: Utsuho gets a lot of traditional nuclear reactor and meltdown imagery and symbolism despite only having power over fusion and not fission. Also, the radiation issues are completely ignored in gameplay.
 * She has power over both fusion and fission. She has two unique shoes on each foot -- the right one is a rock called the Foot of Fusion, while the left is just a black shoe with a model of an atom floating around it called the Foot of Fission. Her Arm Cannon, called Third Leg, controls both (it's mostly All in The Manual). She just uses fusion more often. Also her power is based on solar fusion, not deuterium-tritium fusion; heavy hydrogen has neutrons to give off during fusion, while solar fusion uses protium hydrogen which has no neutrons.
 * In Earth 2150, the United Civilized States forces use nuclear reactors to power their bases. Of course, when a reactor is destroyed, it blows up like a nuclear missile, wiping out half of the UCS base.
 * Averted and played straight in Heavy Weapon. Attacking the atomic bombs that the Atomic Bomber drop will result in the bomb being destroyed (and not exploding), saving your ass from an otherwise-unavoidable One-Hit Kill. However, there is a huge lack of radiation poisoning should any nuke be used.
 * At the end of The Simpsons Hit And Run, you get to cart around nuclear waste. While the barrels will 'explode if you ram something hard enough... you don't get damaged (well, any more than normal). Yet somehow it's supposed to bring down alien technology.

Western Animation

 * In the Futurama episode "Godfellas", the microscopic Shrimpkins make working microscopic H-bombs, complete with tiny mushroom clouds (in space, no less).
 * An episode of Captain Planet -- the one with the equally hilarious stand-in for Hitler -- exemplifies violation #2.2 when a nuclear weapon detonates with a mushroom cloud in space.
 * The Simpsons. Let's start with the 90-gallon drums full of green, glowy nuclear waste and work our way out from there...
 * When Sideshow Bob tries to destroy Springfield with an expired nuclear bomb, we're treated to a tiny mushroom cloud smaller than the bomb itself.
 * Then there's the Treehouse of Horror episode where a nuclear bomb hits Springfield and turns everyone who wasn't killed (or protected by lead based paint) into mutants instantly.
 * That's because the bomb is French and the print on it clearly reads "Le bombe neutron" (not even proper French), and everybody knows that a Neutron Bomb does no physical damage at all.
 * In another Treehouse of Horror episode, Homer blows up the power plant by simply pressing a button- implying that the plant has a self-destruct mechanism.
 * In the second episode of Code Lyoko, XANA's plot of the week is to cause a nuclear power plant to explode with a surge of electricity. Most power grids are, well, wired as a grid, meaning it's impossible to cause a precision surge of electricity as the episode implies. Not to mention that the nuclear reactor itself is just a heat source for a heat engine, so even if the wires didn't melt, the actual result would be that the turbines at the plant would be trashed and the reactor would go through a precautionary auto-SCRAM.
 * Beast Wars introduces an interesting property of the Transformers' energy source Energon, mainly that the radiation its raw form releases shorts out Transformers at high levels, but is completely harmless to organic life at any level.
 * Possibly Justified in that living organisms and machines have slightly different properties. It may have even been a defect of the Transformer's designs themselves, one later corrected in anyone affected by the.
 * The second Teenage Mutant Ninja Turtles series manages to get nuclear explosives right. One of the turtles manages to keep the nuclear part of an implosion bomb from activating... but the conventional explosion still goes off, to little more than a decent blast -- it's actually explained that this will not result in a full-scale nuclear detonation. It's not specifically identified as an implosion bomb, but that's the type this could actually happen with.
 * Odd Subversion of the "All mushroom clouds are caused by nuclear blasts" idea with the old Disney short Dragon Around with Donald Duck and Chip 'N' Dale. In the end Donald tries to  but instead
 * In Hanna-Barbera's short-lived Godzilla cartoon, there's an episode where, no joke, exposure to uranium sends the protagonists back in time. To prehistoric times.
 * Even better: How do they get back? By grabbing piles of uranium in their hands and molding them into balls, of course!

Real Life

 * Chernobyl's scram rods system was defective by design. When inserted into the core, these rods briefly increased the reaction before shutting it down. As it turned down, that brief stage was enough.
 * Almost everyone involved in Chernobyl is to to blame to some extent -- it was a combination of gross mal-operation as well as major design flaws.
 * This was all compounded by Soviet political doctrine, which had classified much information the party had deemed a 'State secret.' None of operating staff knew that the control rods were graphite tipped.
 * They knew — after all that was their job description. They simply didn't understand the implications.
 * The story in a nutshell: the reactor was due to stop for a maintenance and this was considered a good opportunity to test if cheap-and-dirty diesel and regular water pumps work when specialized bells-and-whistles SAOR (system for automatic reactor cooling) fail. The experiment was planned, everyone prepared, but a different reactor in the same plant suffered some troubles and there was not enough power in the energy system during the day. So the experiment was delayed and was to be conducted not by the experienced people from the day shift but by a night shift of "young specialists". At first they made a mistake and and dropped the reactor from 1600 MWt to almost zero (instead of the 700-1000 MWt planned). They did not shut down the reactor at that point as they should have; instead, they removed nearly all control rods to increase power and stabilized the reactor at ~200 MWt, leaving about 6-8 control rods in the active zone (not just a safety violation but a crime). And then they continued with the experiment, disabling one of the main generators and the SAOR (not just a crime but a suicide attempt). To take the SAOR offline, they also had to disable several auxiliary safety devices designed specifically to halt reaction in case of a LOCA (Loss Of Cooling Accident), in other words prevent the exact accident that happened. As expected, water stopped circulating in the reactor and heat started to rise while the diesel pumps slowly started up. Suddenly realizing that the reactor was again gaining power at a rapid rate, the staff pulled the SCRAM. The lower part of the control rods was made from graphite to decrease latency when operated properly, but pulling them back into the active zone briefly resulted in increased reactivity of the reactor. Guess what happened when two hundred rods were dropped into an already overheating unstable reactor?
 * Non-technical summary: A reactor that was designed and built with disgustingly obsolete safety measures was then operated entirely ass-backwards from everything known about safe reactor procedure by inexperienced personnel who had also deliberately hotwired around every single one of the automatic safety systems designed to prevent people from doing what they were doing. In order for Chernobyl to occur, literally every single possible thing that could go wrong had to go wrong, in each and every step from laying out the original blueprints to the final button push. In other words, not remotely likely to happen ever again, especially since nobody else designs and builds reactors according to the Chernobyl specs any longer and the RMBK type reactors still in operation are being operated by people who know exactly how the Chernobyl crew fucked up and will never ever go remotely near that type of stupid shit again. Seriously, the incident report on that disaster was passed out to pretty much every reactor operation crew in the world. (Try reading it sometime if you find a copy. If you can understand the technicalese, you'll simultaneously be laughing and crying.)
 * The fact that the Chernobyl disaster is physically impossible with modern reactors doesn't stop today's opponents of nuclear power from citing Chernobyl in their reasoning. It's the equivalent of Godwin's Law in nuclear power debating circles.
 * Three Mile Island gets a lot of this too. In that one the safeties actually worked. Despite a partial core meltdown occurring, the total amount of radiation exposure to anyone outside the plant was less than what you'd pick up from a chest X-ray.
 * You'll get some supposedly genuine documentaries about Chernobyl throwing out ridiculous numbers either for the sake of drama or some vague anti-nuclear message. Example 1: Saying the thermal explosion that could have occurred if the melted reactor material had come in contact with the water under the core would have be equivalent to a multi-megaton detonation. Not unless a cubic kilometer of water somehow magically flashed to steam. Example 2: Saying radiation in the town nearby was 10,000 roentgens per hour!. This is the equivalent of sitting in the heap of slag that formed under the reactor's cooling units, right after the reactor had melted down.
 * Most people assume that because of the Zone of Alienation surrounding Chernobyl, any kind of nuclear accident will make nearby areas uninhabitable for centuries. However, the real reason the Chernobyl site is blocked off is because pieces of the reactor core were scattered around the country side and then buried in a hurry after during the cleanup. Much of the area around Chernobyl is livable though, as radiation levels have fallen dramatically over the years, as evidenced by the recent appearance of native wildlife to the region. The real danger is the unknown burial sites for the core parts, which could release a lot of radiation if disturbed. The biggest long term ecological concern for the area is about radioactive isotopes that have settled on the bottom of a nearby lake, which while harmless now, could make the water deadly if a dam broke.
 * Events like the crash of the Galileo probe against Jupiter made a bunch of conspiracy theorists start claiming that there are plans to ignite Jupiter into a second sun. Similar predictions were made when the comet Shoemaker-Levy 9 was about to impact Jupiter. For reference, the minimum mass to actually get self-sustaining nuclear fusion in a ball of gas (that is, a small red dwarf star) is around 75 Jupiter masses. So, even if you did manage to initiate some fusion on Jupiter, all you'd get would be a nuclear explosion. That's it.
 * #4.1 was unfortunately played straight in the Goiânia accident -- the misplaced radioactive source in question did apparently have a blue glow once extracted. This encouraged people to play with it, with fatal results.
 * The US Army's Stationary Low-Power Reactor Number One, SL-1, was the site of the most fatal nuclear accident in the United States. The main control rod needed to be manually withdrawn to a certain distance--four inches (approximately ten centimetres)--before the automatic system engaged. On the day in question, the control rod was withdrawn a full twenty inches for reasons unknown, causing the reactor to go prompt critical, resulting in a steam explosion that killed all three operators (pinning one to the ceiling with the control rod). After this the AEC wisely stopped building reactors in which one control rod's removal would cause such a disaster. Of course, the SL-1 is also proof that reactors don't simply explode like an atomic bomb when they go prompt critical, and just how hard it is to make a reactor melt down even in an emergency.
 * The suggestion of one official report states that the control rods and/or their robotic armature had an unfortunate tendency to become 'sticky' and not slide smoothly into and out of their housings. The suspicion was that the unfortunate operator was trying to pull the rod out without the armature, King Arthur style. He completely succeeded and crowned himself king of radiation for a few seconds before he died.
 * There's reason to believe the armature had been left disassembled (not unreasonable given the stage of development) and the techs were putting it back together. Due to an oversight, the reassembly directions given in the manual ("follow the disassembly instructions backwards") were physically impossible, as the rod had to be pulled farther out than needed to take the armature apart. The rod was not gradated to show how far out it was, and a ruler couldn't be placed near it. Further, a conventional reactor design can have up to a hundred rods which can be entirely removed (one at a time) with no danger, while every one of the SL-1's rods was individually critical (the manual never actually said, or laid out the effects of withdrawing a specific rod to a specific range on the reaction process). The SL-1 was intended to power semisecret posts which couldn't receive regular supply shipments, and there may have been forces leading both to sketchiness in the manual and a reluctance for the engineers to request clarification. Unsurprisingly, the official investigation chose to focus blame on those whose careers could no longer be affected by it.
 * For that matter, Fukushima was more of an unforeseen circumstance. The reactors itself were built virtually at the same time as the Chernobyl's one, in mid-Seventies, but to a newer design, so when the disaster struck they successfully withstood the quake and were stopped alright. They took the seashore location into account, by lowering the bluff the site was built on to utilize smaller pumps for the secondary cooling loop that pumped in seawater (To be fair, this also let the reactors sit on solid bedrock which helped their earthquake resistance). The site was designed to survive a more typical 6m tsunami, but not the monster 14m one it was hit with. Thus, the emergency generators that supplied the electricity to the cooling systems of reactors stood on the very edge of the sea and were immediately washed out when the wave came. The designers also put the main distribution point of the whole station into the basement where it was promptly inundated and taken out of service — which would bite the operators in the ass later, when it turned out that the mobile generators that were brought to help from elsewhere were incompatible with the station's systems and could be connected only through the now underwater distribution point...
 * An amusing but little-known fact is that nuclear submarine reactor operators pick up less radiation exposure per unit time than the average civilian -- the increased exposure to the reactor is more than made up for by the cosmic ray background exposure they're not getting because they're shielded by several hundred feet of water.
 * For that matter, spending several months working in the average nuclear power plant exposes you to less rems than the average dental x-ray.