One thing that will mitigate the impact of this compared to an unplanned outage is that Samsung has some warning to stage wafers in safe steps. There's a lot of sections of the manufacturing process for modern chips where it's important the wafers do not sit for long. Typically this is when a material that can oxidize or corrode easily is exposed. One of the reasons even short power interruptions can be so expensive is that partially built wafers often have to be scrapped when they get stranded in one of these sections. Even a few hours warning should let Samsung stage most or all of the wafers at steps where the wafers are covered in corrosion proof materials like silicon oxide (glass).