The Navy used to have nuclear-powered cruisers
While nuclear-powered carriers and submarines are all the rage in the U.S. Navy today, the sea-going service used to have a much wider nuclear portfolio with nuclear-powered destroyers and cruisers that could sail around the world with no need to refuel, protecting carrier and projecting American power ashore with missiles and guns.
The first nuclear surface combatant in the world wasn't a carrier, it was the USS Long Beach, a cruiser launched in 1959. That ship was followed by eight other nuclear cruisers, Truxtun, California, South Carolina, Virginia, Texas, Mississippi, and Arkansas. The Arkansas was the last nuclear-powered cruiser launched, coming to sea in 1980.
During the same period, a nuclear-powered destroyer, the USS Bainbridge, took to the seas as well. Due to changes in ship nomenclature over the period, it was a frigate when designed, a destroyer when launched, but would be classified as a cruiser by the time the ship retired.
The head of the Navy's nuclear program for decades was Adm. Hyman G. Rickover who had a vision for an entirely nuclear-powered carrier battle group. This would maximize the benefits of nuclear vessels and create a lethal American presence in the ocean that could run forever with just an occasional shipment of food, spare parts, and replacement personnel.
The big advantage of nuclear vessels, which required many more highly trained personnel as well as a lot of hull space for the reactor, was that they could sail forever at their top speed. The speed thing was a big advantage. They weren't necessarily faster than their conventionally fueled counterparts, but gas and diesel ships had to time their sprints for maximum effect since going fast churned through fuel.
That meant conventional vessels couldn't sail too fast for submarines to catch them, couldn't sprint from one side of the ocean to the other during contingency operations, and relied on tankers to remain on station for extended periods of time.
Nuclear vessels got around all these problems, but their great speed and endurance only really helped them if they weren't accompanied by conventional ships. After all, the cruisers and destroyer can't sprint across the ocean if that means they are outrunning the rest of the fleet in dangerous waters.
That's why Rickover wanted a full nuclear battle group. It could move as a single unit and enjoy its numerous advantages without being slowed down by other ships.
And the ships were quite lethal when they arrived. Nuclear carriers at the time were similar to those today, sailing at a decent clip of about 39 mph (33.6 knots) while carrying interceptor aircraft and bombers.
The 10 nuclear cruisers (counting the Bainbridge as a cruiser), were guided-missile cruisers. Four ships were Virginia-Class ships focused on air defense but also featuring weapons needed to attack enemy submarines and ships as well as to bombard enemy shores.
The other most common nuclear cruiser was the California Class with three ships. The California Class was focused on offensive weaponry, capable of taking the fight to enemy ships with Harpoon missiles, subs with anti-submarine rockets and torpedoes, and enemy shores with missiles and guns. But, it could defend itself and its fleet with surface-to-air missiles and other weapons.
But the nuclear fleet had one crippling problem: expense. Rickover knew that to ensure that the larger Navy and America would continue to embrace nuclear power at sea, the ships had to be extremely dependable and secure. To do this, ships needed good shielding and a highly capable, highly trained crew.
Nuclear cruisers had about 600 sailors in each crew, while the Ticonderoga-class that took to the sea in 1983 required 350. And the Ticonderoga crew could be more quickly and cheaply trained since those sailors didn't need to go through nuclear training.
Also, the reactors took up a lot of space within the hull, requiring larger ships than conventional ones with the same battle capabilities. So, when budget constraints came up in the 1990s, the nuclear fleet was sent to mothballs except for the carriers.
And even at that stage, the nuclear cruisers cost more than their counterparts. Conventional cruisers can be sold to allied navies, commercial interests, or sent to common scrap yards after their service. Nuclear cruisers require expensive decommissioning and specially trained personnel to deal with the reactors and irradiated steel.