How to shelter at home after a nuclear accident

Sheltering sounds like doing very little compared with fleeing, and it is exactly the other way round: in the first hours of a radioactive release, staying inside with everything closed is the measure that avoids the most dose, by a wide margin. The reason is simple: a plume passes, an evacuation traffic jam does not.

The first twenty minutes

In order, skipping none:

1. Bring everyone and the animals in. Count heads before closing up.
2. Close doors, windows and shutters. All of them, including rooms you are not going to use.
3. Turn off the ventilation. Air conditioning, heating with an outside intake, bathroom and kitchen extractors, heat recovery units. If you have a cooker hood, switch it off and cover the outlet.
4. Shut the fireplace and close the flue. It is a direct air inlet.
5. Cover the obvious gaps. The gap under the front door with a towel or tape, ventilation grilles with sheeting and tape, and any badly fitting frames.
6. Pick the interior room and take there water, food, medication, radio, torch and phones with chargers.

Which room

The same logic as always: mass and distance. The more material between you and the outside, and the further you are from doors and windows, the less dose you receive.

Place	Suitability	Why
Basement	Excellent	Earth all around and no external openings
Interior room, no windows	Very good	Several walls on every side
Central hallway	Good	No glass, walls on both sides
Room with a window	Poor	The opening is the weak point
Attic or top floor	Very poor	The roof accumulates deposited material

Decontaminating on the way in

If you were outside when it started, you are carrying particles on your clothing and skin. Before sitting down in the interior room:

1. Take off your outer clothing at the entrance, peeling it outwards and not pulling it across your face.
2. Put it in a plastic bag, seal it and leave it as far as possible from where you will be. Do not wash it with the rest of the laundry.
3. Shower with warm water and soap. Without scrubbing hard: grazing the skin makes it easier for particles to get in.
4. Wash your hair with mild shampoo only. Conditioner can fix particles to the hair instead of washing them out.
5. Clean the pets that were outside too, before they settle where the family sleeps.

The days of waiting

• Eat and drink only what was sealed: fridge, freezer, tins, bottled water or water from a closed tank.
• Do not use collected rainwater or eat fresh garden produce that was out in the open.
• Listen to the radio at intervals rather than leaving it on: it saves batteries and spares everyone twelve hours of the same bulletin.
• Send text messages, not calls. And use the out-of-area contact from the family plan as a relay point.
• Do not burn anything in a space with the ventilation off: no gas heaters, no camping stoves, no generators.

When it ends

The end of sheltering is announced by the authorities, and is usually measured in hours or a few days. When it comes:

1. Air the house thoroughly before anything else, opening everything wide.
2. Do not dry-sweep outside or shake out clothes and rugs: it raises the deposited dust.
3. Keep contaminated clothing bagged until you are told how to dispose of it.
4. Follow the instructions on food, well water and local produce even if everything looks normal. Contamination is invisible.

To work out how much water and food to keep stored for the size of your household, the kit calculator gives quantities by days and people.