Additional Reading Atomic Weapon and Nuclear Weapons

8/12/2019 Additional Reading Atomic Weapon and Nuclear Weapons

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Additional Reading: The Nuclear Age

On the 6thof August, 1945, weeks before the end of the World War II,an atomic bomb code-named "Little Boy" was detonated over the

Japanese city of Hiroshima.

Three days later, a second bomb, code-named "Fat Man", was droppedon the city of Nagasaki.

The death and destruction wrought by these weapons were

unprecedented, claiming approximately 200,000 lives and obliterating

nearly every single structure within a 1.6km radius around the dropsites.

While the bombings of Hiroshima and Nagasaki may have contributedto Japan's surrender, the ethicality of the use of nuclear weapons

remains a hugely contentious topic today.

What is certain, however, is that the events of 1945 marked the start of the nuclear age formankind.

Nuclear energy has been heralded as one of the cleanest

source of energy in terms of carbon emissions. Today, nuclearpower plants provide about 6% of the world's energy and 1314% of the world's electricity.

However, the pursuit of nuclear power is not without its costs.

The Chernobyl disaster (1986), the Three Mile Island accident

(1979) and the Fukushima Daiichi nuclear disaster (2011) are

all reminders of the risks and hazards that nuclear power entail.

Furthermore, the nuclear arms race between the

United States and the Soviet Union during the Cold

War period caused the number of nuclear warheads to

multiply so much so that any use of the weapon in

actual warfare would lead to Mutual Assured

Destruction.

Even in the relative peace of today, the possibility ofnuclear weapons falling into the wrong hands, such as

rogue states or terrorists, remains a threat to global

peace and stability.

In this chapter, we shall explore the science behind nuclear weapons and find out why atomic

bombs are so devastatingly powerful.


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Atomic Bombs and Nuclear Weapons

To understand how nuclear energy works,

we shall revisit the topic on isotopes thatwe covered earlier.

Radioactive isotopes are used to producelarge amounts of energy in nuclear fission.

This can be done in a controlled way in a

nuclei reactor.

One common fuel used is an isotope ofuranium, uranium-235.

In the reactor, the uranium atoms are

bombarded with neutrons. When the

neutron hits a uranium nucleus, thenucleus breaks up into two smaller nuclei.This is called nuclear fission.

An example is shown.

Mass Defect and Binding energy

The mass of the nucleus is about 1 percent smaller than the mass of its individual protons andneutrons. This difference is called the mass defect. The mass defect arises from the energyreleased when the nucleons (protons and neutrons) bind together to form the nucleus. This

energy is called the binding energy. The binding energy determines which nuclei are stable

and how much energy is released in a nuclear reaction.

The hydrogen-2 nucleus, for example, composed of one proton and one neutron, can beseparated completely by supplying 2.23 million electron volts (MeV)* of energy. Conversely,when a slowly moving neutron and proton combine to form a hydrogen-2 nucleus, 2.23 MeV are

liberated.

*1eV = 1.602!10"19J

Einstein's formula: E = mc2

The mass defect and binding energy are related by theformula E = mc2.

In 1905, Albert Einstein developed the special theory of

relativity. One of the implications of this theory was thatmatter and energy are interchangeable with one another.This equation states, a mass (m) can be converted into

an amount of energy (E), where c is the speed of light.


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Because the speed of light is a large number and thus c2is huge, a small amount of matter

can be converted into a tremendous amount of energy. This equation is the key to thepower of nuclear weapons and nuclear reactors.

During fission, more neutrons are produced. These neutrons cause fission in other uraniumatoms. This is repeated over and over again. This repeated process is called a chain reaction.

A lot of heat energy is produced in a nuclear fission chain reaction.

In a nuclear reactor, this heat energy is used to produce steam which is then used to drive aturbine and dynamo to generate electricity.

When the chain reaction in nuclear fission is allowed to get out of control, an explosion can

occur. This is done deliberately in explosions produced by nuclear weapons. The explosion is

produced by uncontrolled fission of uranium-235 or plutonium-239.

Consequences of Nuclear Weapon

As we see earlier, a small amount of matter can be converted into a tremendous amount ofenergy in a nuclear reaction. Therefore nuclear weapon is far more powerful than any

conventional weapon. The atomic bomb dropped on Hiroshima, the Little Boy, released

between 54 and 75 TJ (Tera- = 1012) of energy, which is equivalent to 13 to 18 kilotons of TNT.

The modern nuclear weapon is even more devastating, as a weapon weighing a little more than

1,100kg is capable of releasing energy equivalent to more than 1.2 Megatons of TNT.

Health RisksMost of the immediate damage caused by nuclear weapons is due to the energy released. This

takes the form of intense heat as well as shock waves which destroys both living things and

structures.

There are many long-term health effects of nuclear weapons as well. Radiation and radioactivefallout affect those cells in the body that actively divide (hair, intestine, bone marrow,

reproductive organs). Some of the resulting health conditions include:

Nausea, vomiting and diarrhea

Cataracts Hair loss Loss of blood cells

These conditions often increase the risk of leukemia, cancer, infertility and birth defects.


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Additional Reading Atomic Weapon and Nuclear Weapons