Loss of cooling water to the condencer is bad news for any thermal power plant. It can lead to damage to the LP turbine through poor steam quality.

I was perhaps a bit too hasty in my initial statement, clearly this reactor tripped because of the cold. I'm not an expert but given a nuclear power plant produces literally gigawatts of low grade waste heat it feels like that should have been possible to work around i.e. for example by bleeding cooling water back at the intake.