It's a security concern but it is not as big a one as Russian gas.
If you import 10 years of gas you import 10 years of gas.
If you import 10 years of uranium for the LWR you imported more like 1000 years of uranium for fast reactors.
Gas is difficult to ship long distances and dependent on pipeline networks. It is hard to substitute American or Middle Eastern gas for Russian gas but easy to replace Russian uranium with uranium from South Africa, Australia and many other places.
