There really is no way to prevent a nuclear blast it is not within your control.
The safest thing to do is to stay far away from the blast site as you possiby can.
Find a shelter built to withstand a nulear bomb with food and water to survive.
Radiation has no odor or property that allows it to be seen. However, there are many types of devices used to measure it.
Local emergency responders will have some of these devices when they respond to incidents that might involve radioactive material.
Your local department of health will use one or more of these devices to analyze samples taken from around nuclear power plants to determine if any radioactive materials are being released.
Scientists have developed the following four major types of instruments to detect and identify radioactive materials and ionizing radiation:
-Personal Radiation Detector (PRD)
-Handheld Survey Meter
-Radiation Isotope Identification Device (RIID)
-Radiation Portal Monitor (RPM)
Some of them are within budget and would be a smart investment.
If you are outdoors when a detonation occurs take cover from the blast behind anything that might offer protection. Lie face down to protect exposed skin from the heat and flying debris. If you are in a vehicle, stop safely, and duck down within the vehicle.
After the shock wave passes, get inside the nearest, best shelter location for protection from potential fallout. You will have about 10 minutes to find an adequate shelter.
Survivors should wear heavy clothes that reduce thier contact with the radiation.
Avoid walls and any other thick materials as they act as storage for the radiation.
Avoid water sources and livestock if you are not 100% sure they have not been affected by the blast.
Staying in underground basements or bunkers can reduce your exposure to radiation by 90%.