To reduce typical gamma rays by a factor of a billion, according to the American Nuclear Society, thicknesses of shield need to be about 13.8 feet of water, about 6.6 feet of concrete, or about 1.3 feet of lead. Thick, dense shielding is necessary to protect against gamma rays.
Get inside a building right away. Cars do not provide good protection from radioactive material. If you can get to a brick or concrete multi-story building or basement within a few minutes, go there. But being inside any building is safer than being outside.
Install eight-inch-thick concrete and steel doors that open out. Add a ventilation and air-filtration system that can be operated with a hand crank in case of a power failure.
The resulting inferno, and the blast wave that follows, instantly kill people directly in their path. But a new study finds that some people two to seven miles away could survive—if they're lucky enough to find just the right kind of shelter.
Blast Wave
At the end of the first second, the shock wave will have an overpressure of 20 psi. at a distance of four tenths of a mile from ground zero. Even the most heavily reinforced steel and concrete buildings will be destroyed.
Usually, concrete is used as a radiation shielding material. It is a popular building material because it is cheap, strong, and easily moldable. It is common for radiation shielding because of its high density and water content, making it a good barrier against radiation such as gamma rays.
Concrete is a relatively cheap material and easy to be cast into variously shaped structures. Its good shielding properties against neutrons and gamma-rays, due to its intrinsic water content and relatively high-density, respectively, make it the most widely used material for radiation shielding also.
Alpha particles can be stopped completely by a sheet of paper. Beta particles travel appreciable distances in air, but can be reduced or stopped by a layer of clothing, thin sheet of plastic or a thin sheet of aluminum foil.
Close and lock all windows and doors, and close fireplace dampers. When you move to your shelter, use duct tape and plastic sheeting to seal any doors, windows, or vents for a short period of time in case a radiation plume is passing over (listen to your radio for instructions).
THE NEXT 48 HOURS
You have been sheltered because of the potential for dangerous levels of radiation in the first 24 hours following a nuclear detonation. After 24 hours, outdoor radiation levels will have fallen significantly but may still warrant protective measures in your area.
Use sandbags as radiation shielding. A single layer of sandbags placed on top of a tank turret or armored vehicle hull provides valuable overhead gamma shielding. Each layer of sandbags reduces the gamma radiation by a factor of two.
Fallout decays rapidly 7-10 Rule: For every sevenfold increase in time after detonation, there is a tenfold decrease in the radiation rate. So, after seven hours the radiation rate is only 10% of the original and after 49 hours (7 x 7 = 49) it is 1%.
While an underground shelter covered by 1 meter (3 feet) or more of earth provides the best protection against fallout radiation, the following unoccupied structures (in order listed) offer the next best protection: Caves and tunnels covered by more than 1 meter (3 feet) of earth.
Buildings provide considerable protection from fallout
A brick building provides better protection from radiation than does a brick veneer building, which is better than that of a frame building. Less radiation exposure (increasing the Protection Factor) is seen at interior locations and below ground.
Radioactive waste from atomic power plants has to be stored for several millennia before it will stop radiating. However, transmutation could neutralize it, making it non-hazardous to a great extent, at least in principle. Vacuum pumps play a key role in this process.
Concrete is by far the most widely used radiation shielding material because it is cheaper, easier to mold into complex shapes, and suitable for neutron and proton shielding against other shielding materials [1].
At a distance of 20-25 miles downwind, a lethal radiation dose (600 rads) would be accumulated by a person who did not find shelter within 25 minutes after the time the fallout began. At a distance of 40-45 miles, a person would have at most 3 hours after the fallout began to find shelter.
Make sure you have an Emergency Supply Kit for places you frequent and might have to stay for 24 hours. It should include bottled water, packaged foods, emergency medicines, a hand-crank or battery- powered radio to get information in case power is out, a flashlight, and extra batteries for essential items.
First 45 minutes: Seek shelter indoors away from windows
Survivors of a nuclear attack would have about 15 minutes before sandlike radioactive particles, known as nuclear fallout, reached the ground.
Lead aprons, lead blankets, and various other types of lead shielding for radiation are the most effective material to fight off x-rays and gamma-rays.
Lead has long been considered "the element of choice" for radiation shielding due to its attenuating properties. Lead is a corrosion-resistive and malleable metal. Lead's high density (11.34 grams per cubic centimeter) makes it an effective barrier against X-ray and gamma-ray radiation.
Potassium iodide (KI) is a type of iodine that is not radioactive and can be used to help block one type of radioactive material, radioactive iodine (I-131), from being absorbed by the thyroid.
To reduce typical gamma rays by a factor of a billion, according to the American Nuclear Society, thicknesses of shield need to be about 13.8 feet of water, about 6.6 feet of concrete, or about 1.3 feet of lead. Thick, dense shielding is necessary to protect against gamma rays.
Gamma rays have so much penetrating power that several inches of a dense material like lead, or even a few feet of concrete may be required to stop them.
The concrete primary shield is 213.4 cm thick and has a 0.318-cm thick mild-steel liner on the reactor side.