I never noticed it before but there is a visual bug, the pipes should connect.
Sodium works by sucking up steam from steam pipes or heating tanks, this directly cools down the reactor but destroys the steam in the process. Sodium reactors naturally overheat and explode rapidly and it's nearly impossible to cool them without using the steam mechanic, the advantage of this is despite overheating easily they output gigantic amounts of heat and have a much higher overheat threshold than other reactors.
As for practicality, they are kinda not as effective as safer reactors using cheaper cores overall, I added them mainly as a final challenge for skilled players, taming a sodium reactor is hard but doable.
Here's a screenshot of a sodium setup I built today after reading this thread, it took some effort but the uranium reactor on the left generates a large amount of steam that feeds into the sodium reactor (theres a pipe behind the cooling towers feeding into the core, you'll just have to trust me)
I'm fairly sure there are also ways to set it up so the sodium uses the steam it generates itself to cool itself at the same time.
Then the sodiums extremely high temperatures can heat lots of tanks in a wider area than a normal reactor which here I'm feeding into a quick turbine setup I threw together, with more work I think you can get probably 20+ gigawatts off a decently designed sodium reactor.