Most of the shelters will not work, the effect of nuclear war will kill most. Look at chernobyl, if they did not pump the water out a secondary blast of 1 - 3mt could have happened.

Chernobyl was 400 Hiroshima atomic bombs, and the radiation made 1000's of km uninhabitable. The Soviet scientists said secondary blast would have made Europe uninhabitable, modern missiles have several warheads of this size in each missile. They even had to put sheep down in England, if war happens and you don't have a underground shelter you will need several Geiger counters. You will need to read the land to figure out where the fallout will be heaviest.