From memory it's a ban per se as USA has given themselves...

From memory it's a ban per se as USA has given themselves wriggle room to still purchase the Russian U if required. The wriggle must end in 2028, so the ban is effectively from 2028. Typical USA with I want the cake and I will eat it too mindset
Russia needs to dosh so for the moment it's BAU as the Ukraine invasion has taken a toll on so many elements of Russia
The lights won't go off but they would have to make up for the reduction in energy somehow. I haven't looked into it but maybe the date of 2028 is due to USA having enough supply for the period or non-Russian suppliers can each increase capacity to make up the shortfall. When you think of it that way the price increase in U may not be as severe as initially thought if the ban passes or Russia says no
Recent announcements have mentioned building enrichment businesses in USA so that also plays into 2028 as well I guess