The three top performers on the ASX 200 today are all uranium miners.

Boss Energy is up 9%, while Deep Yellow and Paladin are up between 6 and 7% on a day where nearly everything else is struggling.

There's not much of a hint in the spot price of uranium.

It's been sliding for most of the year, down 22% from its post-GFC high of $US100/lb in January.

Talk of supply shortages in Russia sparked a bit of interest earlier in the month, but today's bounce seems to have come from reports of restarting a unit at Three Mile Island in Pennsylvania.

Microsoft and Constellation Energy signed a deal over the weekend to resurrect a unit at the plant which suffered a partial meltdown in 1979 in one of the biggest industrial accidents in US history.

Reuters reports the plan would revive Unit 1 of the five-decades-old facility in Pennsylvania that was retired in 2019 when it was no longer economic to run.

Unit 2, which had the meltdown, will not be restarted.

Microsoft's interest is obvious, given the already massive and growing demand for electricity to power data centres needed to expand artificial intelligence and cloud computing technologies.

However, the plan still requires federal, state and local approvals.

"It's up to Constellation to lay out its rationale for justifying a restart, so we're prepared to engage with the company on next steps," Nuclear Regulatory Commission spokesperson Scott Burnell, told Reuters.

Constellation plans to spend about $US1.6 billion to revive the plant, which it expects to come online by 2028.