Naquadria is a highly unstable radioactive isotope of Naquadah which has the potential to be an enormously powerful energy source. Even a small amount is capable of emitting a pulse of energy far greater than that of weapons-grade Naquadah. As such, when used as a weapon, it has the potential to be as (if not more) powerful as a Naquadah-enhanced nuclear warhead.
Naquadria is a heavier, less stable isotope than Naquadah that does not occur in nature. It was discovered on Kelowna, where ancient writings revealed that Thanos, the Goa'uld who had occupied the planet thousands of years ago, had been experimenting with the mineral. Thanos had managed to create a small amount of Naquadria by developing a process to convert raw Naquadah, but he had been killed in a cataclysmic event that nearly destroyed the planet 3,000 years ago. The resulting explosion released a massive bombardment of subatomic particles which triggered a chain reaction and catalyzed the conversion of a vein of Naquadah near the planet's surface. While Naquadria was created on Kelowna by Thanos, it has also been found on other planets believed to be former Goa'uld testing grounds, such as P4X-351 and the Lucian Alliance outpost planet.
In 20,000 years, the converted Naquadria would have decayed back into Naquadah, however the Kelownans mined the mineral and began to research its use for weapons technology. When Dr. Kieran and his team of scientists successfully tested a Naquadria bomb, its destructive power exceeded all expectations. However, subatomic particles from the explosion penetrated the planet's crust and triggered the conversion of a second, deeper vein of Naquadah. As the conversion process traveled deeper underground, the heat and pressure increased until the highly unstable nature of the resulting Naquadria threatened to explode and obliterate Kelowna. The process could not be reversed, however SG-1 cooperated with the Kelownans and used a Deep Underground Excavation Vehicle to deposit a small Nuclear warhead near a minor fault line crossing the vein of Naquadah in order to trigger a shift along the fault and isolate the advancing Naquadria. The mission was successful, and Kelowna was spared.
Long-term exposure to Naquadria radiation can cause a unique form of brain damage with symptoms of paranoia, delusions, and hallucinations. The Kelownan scientists who worked on the Naquadria Project, including Tomis Lee and Jonas Quinn's mentor Dr. Kieran, all developed advanced schizophrenia due to improper shielding of Naquadria during their research. There was also a lab accident involving the experimental Naquadria weapon in Kelowna that exposed Dr. Daniel Jackson to lethal doses of radiation; which would have taken his life had he not ascended. (SG1: "Meridian", "Shadow Play", "Fallout")
Several hundred pounds of the mined Naquadria had been acquired from Kelowna by Stargate Command for use in developmental hyperspace technology. The experimental X-302 hyperspace fighter craft was designed with Naquadria-powered hyperspace generators. However, the instability of Naquadria increases exponentially as more energy is extracted from it, and the X-302 was unable to maintain a stable hyperspace window. A more successful buffered Naquadria reactor module was designed for the X-303 Prometheus, enabling the ship to achieve limited hyperspace travel. However, the instability of the Naquadria caused a power overload, and the reactor module had to be jettisoned, stranding the Prometheus near Tagrea until repairs could be made. (SG1: "Redemption, Part 1", "Prometheus", "Memento")
The SGC has thus far pursued Naquadria research for use in hyperspace, shield, and weapons technology— the Mark IX Naquadria-enhanced Nuclear warhead being a prime example. However, the Tau'ri's interest in Naquadria has, more recently, declined due to the extremely advanced technology gifted to them by the Asgard. Because of this, Tau'ri ships, notably Daedalus-class vessels, are outfitted with such technologies as Asgard hyperdrive systems, capable of propelling ships at far greater speeds than Naquadria-fueled reactors would have been capable of achieving, if they had managed to get them fully functional. (SG1: "Beachhead", "The Shroud", "Unending")
In 2007, Stargate Command found a rare world 21 light years from Earth that housed an entire core made of Naquadria, the formation of which was the result of the planet being a former Goa'uld or Ancient testing ground. This world later became the site of Icarus Base, a project designed to tap the unstable planetary core and use the Naquadria to power a Stargate dialing a 9 Chevron address found in the Atlantis database.
This world was destroyed in 2009 by a combined attack on Icarus base by the Lucian Alliance and an attempt to dial the 9 chevron address which introduced an uncontrolled instability in the planet's Naquadria core, resulting in the destruction of the planet. It remains unknown if the SGC had mined any Naquadria from Icarus for future uses. (SGU: "Air, Part 1")
Another planet was later found that had a Naquadria core. This world was where the Lucian Alliance set up a research outpost so they could dial the 9th chevron. The planet possessed a pyramid further indicating that it was once under the control of the Goa'uld. After capturing Dr. Nicholas Rush in Colonel David Telford's body, Commander Kiva took him to this planet to force him to help them dial the 9th chevron. After Telford's brainwashing was broken by Colonel Everett Young, Telford gave up the location of this planet and the George Hammond was sent to attack it, launching F-302 fighter-interceptors once it arrived. Desperate, Kiva dialed the 9th chevron even though doing so at that time would cause the planet's core to go critical like P4X-351's core did and sent her forces through to Destiny. The Hammond was forced to flee and leave behind two of its F-302s due to time constraints and the planet exploded, killing over 100 Lucian Alliance soldiers and the two 302 pilots. (SGU: "Subversion", "Incursion, Part 1")
Alliance Naquadria BombsEdit
The Lucian Alliance, using Naqaudria gotten from an unknown source, possibly their Icarus-like planet, built Naquadria bombs of their own in the 50-70 megaton range. They planted one on two Tau'ri bases and in an attack on Earth by having a Tel'tak carrying one of the bombs flown to Homeworld Command, where it crashed. This bomb was attempted to be disarmed by Camile Wray, who failed but succeeded in disarming by Senator Michaels using instructions from Varro who was familiar with the bombs. (SGU: "Alliances")
In 2010, the unified governments of Langara had agreed to transfer the planet's Stargate into a newly established power plant in Kelowna that had been designed to harness the energy from the Naquadria core. Both Stargate Command and the Lucian Alliance petitioned the Langaran government separately in hopes of utilizing their Stargate to dial the Ancient starship Destiny. Both requests were denied by the Langarans, as they were aware of the effects of the previous two dialing attempts made on P4X-351 and the Icarus-like planet, endeavors that resulted in the total annihilation of the planet itself. Despite Dr. Rodney McKay's assurances that their further understanding of the process and his development of a safe procedure, the Langarans refused. The Destiny expedition and Homeworld Command devised a plan to trick two Langaran officials into leaving their imprint on the Ancient Long-range communication stones, thus allowing Lt. Matthew Scott and Colonel Everett Young to swap consciousnesses with them and impersonate them. Young and Scott then used the officials authority to allow the Tau'ri to dial Destiny. However, the plan was foiled when the Langarans discovered the reality and a standoff ensued with the Tau'ri backing down. In an act of diplomacy, Richard Woolsey offered Earth's help in the defense of Langara against the Lucian Alliance whom the Langarans were warned would not be so kind in their efforts to attempt what the Tau'ri attempted. As an added precaution, the stargate was moved back out of the power plant, so that it could not be used to dial Destiny. (SGU: "Seizure")