This document discusses different types of nuclear weapons and their mechanisms of action. It describes how fission weapons work by splitting atomic nuclei to cause a chain reaction and release energy. Fusion weapons join light atomic nuclei and also release energy. Some weapons combine fission and fusion in their design or are designed for specialized purposes. The document also notes that hundreds of atmospheric nuclear tests released radioactive fallout that posed health hazards.

1. At the centre of every atom is a tiny
powerhouse called a nucleus .Strong forces
hold particles called protons and neutrons
together inside the nucleus .In nuclear
reactions, atomic nuclei split apart (fission)
or join together (fusion),rearranging the
forces between the particles and releasing
huge amounts of energy called nuclear
power.

2. WHAT ARE NUCLEAR WEAPONS?
 A Nuclear weapon is an explosive device that
derives its destructive force from nuclear reactions
,either fission or a combination of fission and fusion.
Both reactions release vast quantities of energy
from relatively small amounts of matter. Two
nuclear weapons have been used in the course of
warfare, both times by the United States near the
end of World War II.

4. TYPES OF NUCLEAR WEAPONS
Fission Weapons Fusion Weapons

5. FISSION WEAPONS
 When the nucleus of an atom splits apart it is called
Nuclear Fission .Some heavy elements have
unstable nuclei that can be made to split by
bombarding them with neutrons. As the nuclei split,
they release energy and more neutrons, which may
strike other nuclei and start a chain reaction. In
fission weapons, a mass of fissile material(enriched
uranium or plutonium)is assembled into a
supercritical mass.

6. FUSION WEAPONS
 The joining together of two atomic nuclei is called
Nuclear Fusion. Only light elements- those with
few protons and neutrons in their nuclei-can take
part in nuclear fusion reactions. Fusion reactions
occur in the sun and other stars. Fusion weapons
are generally referred to as Thermonuclear
Weapons. Fusion reactions do not create fission
products, and thus contribute far less to the
creation of nuclear fallout.

7. OTHER TYPES
 There are other types of nuclear weapons as well.
For example, a boosted fission weapon is a fission
bomb that increases its explosive yield through a
small amount of fusion reactions, but it is not a
fusion bomb. In the boosted bomb, the neutrons
produced by the fusion reactions serve primarily to
increase the efficiency of the fission bomb. So
some weapons are designed for special purposes.

8. Nuclear Fallout
Over 500 atmospheric nuclear weapons tests were
conducted at various sites around the world from 1945
to 1980. Radioactive fallout from nuclear weapons
testing was first drawn to public attention in 1954. As
public awareness and concern mounted over the
possible health hazards associated with exposure to
the nuclear fallout, various studies were done to assess
the extent of the hazard.

9. The waste from nuclear fuel is dangerously
radioactive, so it must be dumped at sea
or buried safely underground. Nuclear
weapons tests and accidents at reactors
can cause long-term health hazards by
releasing radioactive material into the air.

10. I have done research on this topic from:
Book encyclopedia
Website Wikipedia
Website rpfuller.com