That's not really such a big problem.
There are only 4 states which depend on those, Bulgaria, Hungary, and the Slovakia Czech Republic duo, with less than 10GW, and furthermore, Westinghouse can produce the fuel, is just that all these countries have contracts with Russia and the replacement of fuel was already planned.
Allow Romania to restart all its coal powerplants and there you go, 12 GW capacity with interconnection just in the middle of the problem.
Nuclear fuel will be easy, oil will be tricky, gas is the problem!
There was less trade being done at that time, look for example the volume in shipping, the war didn't come after a lockdown that fucked the logistic chain forever and still keeps 1/4 of China messed up, and more important that was Irak, it wasn't a clash at the door of the second economy if we count EU as a whole.