7/23/2019 Types of Nuclear Explosions

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Types of Nuclear Explosions

The effects of a nuclear explosion depend in part to the height of the detonation. There five general classifications of bursts: air,

high-altitude, underwater, underground, and surface bursts.

An air burst is defined as one in which the explosion occurs in the air at an altitude below 100,000 feet (30,480 meters), but at

such a height that the fireball does not touch the surface of the earth. A detontation above that altitude is generally refered to as a

high-altitude burst.

A nuclear explosion that occurs at or slightly above the actual surface of the land or water is known as a surface burst. If the

explosion happens beneath the surface of the land or water, then it is known as underground or underwater respectively. The

design of Robust Nuclear Earth Penetrator (RNEP) uses the charaterastics of an underground burst in an attempt to destroy buried

targets.

One of the greatest results of the type of burst is the amount of radioactive debris and fallout, and the force of the blast wave.

Overpressure

Blast effects are usually measured by the amount of overpressure, the pressure in excess of the normal atmospheric value, in

pounds per square inch (psi).

After 10 seconds, when the fireball of a 1-megaton nuclear weapon has attained its maximum size (5,700 feet across), the shock

front is some 3 miles farther ahead. At 50 seconds after the explosion, when the fireball is no longer visible, the blast wave has

traveled about 12 miles. It is then traveling at about 784 miles per hour, which is slightly faster than the speed of sound at sea

level.

Peak overpressure Maximum Wind Speed

50 psi 934 mph

20 psi 502 mph

10 psi 294 mph

5 psi 163 mph

2 psi 70 mph

As a general guide, city areas are completely destroyed by overpressures of 5 psi, with heavy damage extending out at least to the

3 psi contour.

These many different effects make it difficult to provide a simple rule of thumb for assessing the magnitude of injury produced by

different blast intensities. A general guide is given below:

Overpressure Physical Effects

20 psi Heavily built concrete buildings are severely damaged or demolished.

10 psi Reinforced concrete buildings are severely damaged or demolished.

Most people are killed.

5 psi Most buildings collapse.

Injuries are universal, fatalities are widespread.

3 psi Residential structures collapse.

Serious injuries are common, fatalities may occur.

1 psi Window glass shatters

Light injuries from fragments occur.