What are nuclear-powered submarines and how do they work? Australia’s new firepower explained

Hong Kong (CNN) With Australia making a deal with the United States and United Kingdom to begin a nuclear-powered submarine program, we can expect the Aussie subs will look a lot like the latest versions in the US and British arsenals.

The fleets of the US Navy and Royal Navy have two kinds of submarines — categorized as attack and ballistic missile. Both are powered by nuclear reactors, which convert water into high-pressure steam that turns turbines to propel the subs.

But attack subs and ballistic missiles subs — often called “boomers” — serve very different purposes. Australia is signing up for the nuclear-powered option, or attack sub, rather than the boomers, which are nuclear-armed, with nuclear warheads on their ballistic missiles.