Yesterday Samsung's facility in Hwaseong, South Korea, suffered a one-minute long power outage, which has led to an estimated two- or three-day recovery time to get the production line back online, as reported by Yonhap. This factory produces DRAM and NAND memory. The power outage was caused by a power cable explosion at a nearby power substation.
Yonhap was informed that Samsung's machinery suffered no major damage, however, currently, the production line is under investigation to ensure it is ready to resume operations by the weekend.
Regardless of major damage or not though, any wafers that were in production would have to be scrapped, as even a very brief power outage could render them useless. These, along with any downtime until recovery is why even a brief outage can lead to significant losses.
No specifics were given with regard to the extent of the damage, but for reference, in 2018 Samsung's Pyeongtaek factory experienced a 30-minute blackout which caused about 50 billion won (US $43.3 million) in losses. All that Yonhap was able to report is that the damage is in the 'few billion' won range.
Nevertheless, in 2018 DRAM and NAND prices were significantly higher, and Samsung currently has a significant inventory, so chances are the actual damage won't be quite as severe for this incident as the 2018 Pyeongtaek outage.