Effects of Nuclear Explosions

By Carey Sublette

Nuclear explosions produce both immediate and delayed destructive

effects. Immediate effects (blast, thermal radiation, prompt ionizing

radiation) are produced and cause significant destruction within

seconds or minutes of a nuclear detonation. The delayed effects

(radioactive fallout and other possible environmental effects) inflict

damage over an extended period ranging from hours to centuries, and can

cause adverse effects in locations very distant from the site of the

detonation. These two classes of effects are treated in separate


The distribution of energy released in the first minute after

detonation among the three damage causing effects is:

                      Low Yield (<100 Kt)   High Yield (>1 Mt)

Thermal Radiation        35%                      45%

Blast Wave               60%                      50%

Ionizing Radiation        5%                       5%

(80% gamma, 20% neutrons)

The radioactive decay of fallout releases an additional 5-10% over