Zero chance nuclear plants get shut down—.gov would nationalize them first...
More likely .gov would guarantee nuclear plants they couldn’t be sued—there is no way, no chance, they would be allowed to shut down.
You have a very unrealistic view of the bureaucracies and politics involved with nuclear power and COVID-19.
There is no way to maintain safe operation against an airborne pathogen without robust level-4 P.P.E for the nuclear control room operators.
And there won’t be any until after most are infected and many have died.