What is the nuke sniffer? America's strange plane that could detect Iranian nuclear tests visits the Gulf

The 'Constant Phoenix' lands in Kuwait as Iran intensifies its nuclear programme

The US Air Force can use the 'Constant Phoenix' to detect nuclear explosions. AFP

Since the mid-1940s, the US Air Force has operated a nuclear explosions detection unit. A "bomb sniffing" plane called the Constant Phoenix plays a key role in this effort.

The unusual aircraft made its way to the Arabian Gulf and landed in Kuwait, according to online flight tracking services and reported by open-source analysis project Aleph.

The nuclear bomb-detecting plane arrived in the region as Iran intensifies its nuclear production project and faces off with the US over a potential new agreement on nuclear research and an end to sanctions.

Although the reason for the Phoenix's arrival is unknown, the history of the plane and its purpose could point to its current mission.

It was most recently used in 2016 to investigate claims by North Korea that a nuclear weapons test had been conducted.

This aircraft is designed to fly through clouds of radioactive debris to collect air samples and catch dust. It then measures the air for radioactive isotope particles – evidence of a nuclear explosion.

The plane's crew have their radiation exposure levels monitored and are kept safe using special air filtration systems.

Although the Comprehensive Nuclear-Test-Ban Treaty Organisation operates 80 monitoring stations around the globe that check the air for "fission fragments", sniffer planes can assess the atmosphere more quickly.

When a nuclear test occurs underground, fission fragments are trapped, except for some gas particles.

Those particles eventually make their way into the atmosphere where they can be detected with the right equipment.

How much information a sniffer plane can collect depends on how much material was released from the test site and how quickly the sniffer plane can arrive at the location.

As of now there have been no reports of nuclear explosions in the region and no tremors detected that could indicate a massive blast.

But with tensions increasing and time running out on possible talks about the US returning to the 2015 nuclear deal signed by Iran and global powers, the Biden administration may be preparing to use the Constant Phoenix to carry out checks on Iran.