What If Nuclear-Powered Aircraft Carrier Explode at Sea?

Aircraft carriers are pretty much 'moving air force bases in sea'. Such is this invention that these ginormous ships have bigger threat of being attacked than an entire naval base during a war. Going for aircraft carriers are often seen as primary approach when a particular navy is meant to be crippled. Thoughts might occur that during a volley of fire, the only offense a carrier can do is to deploy its onboard jets and hope not to be a sitting duck. But that's not the case here. Every aircraft carrier is itself very light in armaments and whatever there are present, they are mostly used for close-range self-defence. But no carrier currently in active service will move alone once deported for combat, but rather go along with a group of ships (consisting of destroyers, frigates, corvettes or cruisers, and sometimes submarines) - known as a Carrier Battle Group. But what does it actually take to destroy/sink an aircraft carrier? Now for the exciting part, let's consider an American nuclear-powered aircraft carrier moving in a strike group which is soon to be hit by Chinese hostilities. But before that, let's have some logical assumptions. *The following scenario is a hypothetical script made completely based on open-source information, author's assumptions and knowledge (however a similar event if happens in real life won't have too much deviation) *For incoming fire, the aircraft carrier has been set as the priority target. Realistically, for a carrier strike group to be rendered it must be struck with some serious destructive warhead or nuclear weapons (because generic missiles will either be obliterated before it even comes close, or will just be named as minor mishaps even if they do hit). In this hypothetical scenario China has been chosen as the attacker with only nukes in question. *Carrier battle groups of USA are known officially known as a Carrier Strike Group (CSG). US Navy's Carrier Strike Group 5 (CSG 5/CARSTRKGRU 5) of the United States Pacific Fleet has been chosen as the defender. Let the electrifying, high-octane simulation scenario begin (with a bit of detailed information): Flight deck of USS Ronald Reagan (shown in fig. 1 E2D Hawkeye and FA-18E/F Super Hornets) (Image source – CBS News) US Navy has 11 nuclear-powered aircraft carriers as of now with 9 active Carrier Strike Groups globally (this number may vary by a unit or two if the lead carriers go for multi-year maintenance/retrofit operations in their respective dry-docks). The Carrier Strike Group 5 is the largest of all the battle groups of US. Before 14 Jan 2014, the Nimitz Class USS George Washington was the lead ship of this group but has been replaced by the Nimitz Class USS Ronald Reagan (CVN-76). The USS Ronald Reagan is a 101400 ton supercarrier powered by 2 Westinghouse A4W Nuclear Reactors. It carries the Royal Maces, Diamondbacks and Dambusters squadrons of F/A-18E Super Hornets, Argonauts squadron of F-35C Lightning-II, Shawdowhawks squadron of EA-18G Growler, Tiger Tails of E2D Hawkeye, Providers of C2A Greyhound, the Golden Falcons and Saberhawks squadrons for the MH-60 S/R Seahawk helos. It is accompanied by the Destroyer Squadron 15 featuring the USS Benfold, USS Milius, Higgins, Howard, McCampbell, Shoup, Dewey, John Finn, Ralph Johnson and Rafael Peralta - Arleigh Burke class destroyers, and two Ticonderoga class battle cruisers (USS Antietam and USS Robert Smalls). All of these platforms together make the Carrier Strike Group 5 - the largest active carrier battle group in the world. This group is assigned to the bigger Pacific Fleet, permanently forward deployed to the US 7th fleet and its homeport is the United States Commander Fleet Activities Yokosuka, an US Navy base in Yokosuka, Japan - which makes it a very close and predictable target for China, if all everything goes south in an all-out war. USS Ronald Reagan leading the CSG-5 in Exercise Invincible Spirit, Korean Peninsula, 2016 (Image credits – US Navy Petty Officer 3rd Class Nathan Burke) So here comes the event! Assume the entire CTG-5 is out in the open seas somewhere in the Pacific, off the eastern coast of Japan - which is easily within reach for every nuclear/non-nuclear ballistic missile present in the Chinese arsenal. The fleet is on high alert and during these times, jets aboard the carrier are all ready in insta-deployable state. A certain number of jets (impossible to guess a number, depends on seriousness of imminent danger) will already be up in the air scanning the skies for incoming missiles. US Navy uses the combination of EA-18G Growler and F-35/FA/18 for simultaneous electronic warfare-jamming-aerial attack ops. Not risking any aircraft loss, China deploys 5 J-16s from far away armed with 10 KS-88 air-to-surface missile having 200km range. 3/4 out of 10 will be destroyed by counter fire from the F-35s and F/A-18s while the rest are still going at Mach 0.85 aimed for the carrier. However each one of those will be obliterated before they even come close. One of the most important purpose of carrier battle groups is also the protection of the carriers. The entire CSG comes with equipped with 20 Phalanx CIWS and a similar no 25mm Mk38 and 127mm Mk45 machine guns. With a maximum range of 5500m and an effective single target range of 1500m, the 6-barrel 20mm Armor-piercing discarding sabot/incendiary tracer rounds has been the go-to CIWS for the entire US Navy and absolutely eviscerates incoming missile fire and aircrafts. To keep the entire carrier group busy in dealing with the KS-88s, China orders a neighboring Kilo Class diesel-electric attack submarine to go guns-blazing. Armed with 4 Kalibr anti-ship missiles, the Kilo sub fires its entire salvo of Mach-2 Kalibrs to attack the Ronald Reagan. But little did they know that the entire carrier group is equipped with more than 30 Mk-32/46/50/54 torpedo tubes and Harpoon UGM-84 submarine-attack variant missiles. The different AN-SPY radar variants in the carrier and every other destroyer in the group are already scanning their max capable area to detect incoming threats. In the same time while the KS-88s have been neutralized, 3 ships are already engaged in deploying Mk-36 Mod 12 infrared decoys, Harpoons and Phalanx for the cruise Kalibrs, simultaneous sending a batch of Harpoons and Mk50 torpedos to delete the Kilo class. In the meantime, China has understood that sending jets or conventional missiles is nothing but bleeding out money with no damage to the intended US targets. Their strategic commands are already ordered to ready out ICBMs to sink the Ronald Reagan. Whether it is a war scenario or normal patrol route, carrier groups never stop. Despite now being in the eyes of Chinese submarines, the Reagan outruns most of Chinese attack submarines with its 56kmph top speed. Time for the big guns as China moves on from marking the Ronald Reagan as a single target to obliterating the entire CSG-5 as a area target success. Enough of the annoyance as China readies 2 Dongfeng-26 and 2 Dongfeng-41s. The DF-26 is a 5000km IRBM which has been nicknamed as 'Carrier Killer' since China released a footage of a mock carrier being successfully hit in a trial. The DF-41 is a 15000km ranged ICBM which can carry upto 15 warheads including decoys, and has overtaken the US' LGM Minuteman III by now being the longest-ranged ICBM (upto 15000 kms). China has heard how effective US Navy's AEGIS is and despite a single ICBM is probably enough to make serious damage to such an aircraft carrier (provided the right amount of warhead + accuracy works). The entire CSG-5 is matched with the Aegis Ballistic Missile Defence System where the Arleigh Burke class destroyers can immediately catch on to enemy ballistic missiles fired in the sky and has the ability to intercept them in their mid-course phase or terminal phase using the RIM 161/67/174 missiles present on the ships. If China launches a single DF-26, there is chance that it might get intercepted so it decides to fire a salvo of these with 2 DF-26s and 2 DF-41s. ICBMs like DF-41s are extremely well-designed trump cards in a all-out war to overpower enemies using multiple warheads rushing all intended for a single target. At this stage, the USS Ronald Reagan and its fleet all are using their magazines out and destroy them. Assuming 50% of the incoming warheads get intercepted and 50% of them hits successfully across all the units of the group, the Ticonderoga and Arleigh Burkes will probably be destroyed/rendered useless immediately. But will the Reagan be done for? We don't know what we don't know. US' nuclear-powered super carriers are already tested with atomic explosions before induction in the navy and the way their vessels have withstood tests so many times in history can really raise the Chinese eyebrows if it is not sunk immediately. Dongfeng-41 ICBM (Image source – Missile Threat – CSIS) Everything said till now are all based on imaginary analysis with respect practical equipment on ground. In reality, nobody knows how it will play out until a nuclear-powered carrier somehow actually sinks to make the entire world's jaw drop. Different analysts of various countries simulate different scenarios and the above shown scenario may be completely wrong if such doomsday appears. This entire topic is a very classified and sensitive issue even among the highest ranks of global military powers. What actually happens? Any Actual Reports? If a missile managed to get through the side of a carrier into the reactor space, and managed to breach the reactor containment vessel, the core would likely lose all cooling and melt into ‘”corium” and burn through the ship and into the ocean depths. A nuclear meltdown is a severe and dangerous condition in a nuclear reactor where the reactor core overheats and the fuel rods begin to melt. The reactor core requires continuous cooling to maintain a safe temperature. If the cooling system fails or is insufficient, the core can overheat. As the temperature rises, the fuel rods, which contain nuclear fuel (typically uranium or plutonium), can start to melt. This process is called a meltdown. If the meltdown continues, it can damage the reactor core structure and potentially lead to the release of radioactive materials. If the meltdown continues, it can damage the reactor core structure and potentially lead to the release of radioactive materials into the entire ship. Pressure vessels used in aircraft carrier are enclosed within several layers of hardened metals and it’s tough for any missile to hit that, and are also designed to go for instantaneous emergency shutdown if system fails in the path. Till now there are 0 sunk nuclear aircraft carriers since US' Nimitz class, Gerald R. Ford and France's Charles de Gaulle are the only nuke-powered carrier in history, all of which are active and none has faced threats even close to be rendered useless in an explosion. The closest incident is the intentional sinking of the USS Saratoga which was used as a test sample after its decommissioning to study the effect of atomic explosions in aircraft carriers. The USS Saratoga was a 36000-tonne Lexington-class aircraft carrier of the World War I/II era which had a 17-year exceptional service record with 8 Battle Stars honor and returning the highest number of veterans during the wars. After WW2, the ship was chosen for Operation Crossroads in the Bikini Atoll where it was meant to be sunk under the effect of an atomic bomb test. The ship survived the first test on 1st July 1946, Test Abel with just minor damage on the flight deck. On 25 July 1946, a much stronger Test Baker was conducted where the underwater blast was detonated 370m under the Saratoga - the force of which knocked the vessel of the water allowing to meet the planned demise. Operation Crossroads’ Test Able which the USS Saratoga successfully survived with just minor damage (Image source – now-declassified US Atomic Archives) Operation Crossroads’ Test Baker where the USS Saratoga met its demise (Image source – Atomic Archives) It’s close to being a century worth of milestones in military innovation and it definitely speaks volumes of how much sturdy today's carrier battle groups are. Ignoring geopolitics, with lack of actual data, it becomes difficult to predict how nature would react in a concerning explosion. The Nimitz, Gerald Ford classes and Charles de Gaulle don't carry any nuclear warhead-carrying weapons but come under nuclear-powered aircraft carrier categories since the entire power of the platform's operation is drawn out from a nuclear reactor instead of conventional diesel engines. These are pressurized water reactors where water is pumped under high pressure as the primary coolant to the reactor core where it is heated by the energy released by the fission of atoms. The heated high pressure water goes through a couple of steam generator systems which powers the turbines. While the actual system is much more complex, it is quite similar to the operation of actual nuclear power plant and is the same for the active nuclear-powered carriers and submarines. Perfect functioning requires the perfect combination of pressurization of coolant, quality of high pressure vessel, high-strength piping, chamber/compartment material specifications etc. USS Gerald R. Ford’s successful final 3-phase shock trial (detonation of 40000 pound charge right off the starboard beam which resulted in a 3.9 Magnitude earthquake, but the ship cleared trials) (Image credits – US Navy Petty Officer 2nd Class Novalee Manzella) Loss-of-coolant accident: Similar to actual nuclear power plants, even nuke-powered carriers and submarines have an emergency nuclear reactor shutdown mechanism used for immediate termination of nuclear fission reaction. If coolant flow is reduced/stopped, the reactor's emergency shutdown is designed to stop the fission reaction, but sometimes radioactive decay may continue to create a significant amount of heat subsequently compromising containment procedures and radioactive leaks are bound to happen. The infamous 2011 Fukushima Daichi nuclear accident of Japan is the most prominent example of this type of disaster and nuke-powered military platforms are also prone to this mishap. The November class submarines were the first nuclear-powered attack submarine of the Soviet Union. One of the units - Project 645 K-27 faced a loss-of-coolant situation. During a trial exercise on 24 May 1968 in the Barents Sea, an emergency occurred in one of the port-side reactor (left side of the vessel towards the moving direction), the nuclear shutdown mechanism didn't work perfectly, gamma activity rose to abnormal levels and radioactive gases started spreading across all compartments. In addition, there was ignorance between crew members and right orders weren't complied. Accident came not in the form of any explosion but radioactive outbreak prevailed in the compartments and 5 crew members died due to overexposure to radiation. Later the K-27 was sunk by scuttling in Stepovoy Bay, Kara Sea, 1982 at a depth of 40m (ignoring the requirement of International Atomic Energy Agency's requirement that the nuclear-powered submarine had to be scuttled at a depth of 3000-4000ms). Soviet K-278 Komsomolet wreck in the Norwegian Sea, still armed with two active nuclear torpedos to this date (Image source – Reddit archives) The Soviet nuclear submarine K-278 Komsomolets sank on April 7, 1989, in the Norwegian Sea after a fire broke out in its reactor compartment, leading to a loss of power and control. The fire, which was caused by an electrical fault, quickly spread and led to a catastrophic failure. Emergency shutdown went off and the sub lost propulsion while under water. It was made to resurface after performing a controlled explosion of the ballast tanks. In 1994, plutonium leakage was detected from the wreck of the sub’s nuclear-armed torpedos which are still active to this date. Divers were sent to fix the hull compartments with radiation-proof sealants. Norwegian authorities from the Marine Environmental Agency and Radiation Agency take water and ground samples from the vicinity of the K-278 wreck on a yearly basis. Actual explosions during any system failure doesn’t happen as such because the damage dealt is spread through leakage of radioactive elements. Being same for both nuclear aircraft carriers (0 for now) and nuclear submarines (9 for now), countries choose to let wreckages rest deep under the sea to keep the probable leaks off with the help of water. Water is itself a good insulator of nuclear radiation and although aquatic life in the immediate region of the explosion/leak remains in danger, it absorbs the neutrons released in the fission reaction and acts like a blanket to cover the reactor.