Nuclear Reactions Fission and Fusion. Fission Nuclear fission in the process whereby a nucleus, with a high mass number, splits into 2 nuclei which have.

Nuclear Reactions

Fission and Fusion

Fission

Nuclear fission in the process whereby a nucleus, with a high mass number, splits into 2 nuclei which have roughly equal smaller mass numbers.

During nuclear fission, neutrons are released.

There are 2 types of fission that exist:

1. Spontaneous Fission

2. Induced Fission

U23592n

1 0

The Fission Process

A neutron travels at high speed towards a uranium-235 nucleus.

U23592n

1 0

The Fission Process

A neutron travels at high speed towards a uranium-235 nucleus.

U23592n

1 0

The Fission Process

A neutron travels at high speed towards a uranium-235 nucleus.

U23592n

1 0

The neutron strikes the nucleus which then captures the neutron.

The Fission Process

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The nucleus changes from being uranium-235 to uranium-236 as it has captured a neutron.

The Fission Process

The uranium-236 nucleus formed is very unstable.

The Fission Process

It transforms into an elongated shape for a short time.

The uranium-236 nucleus formed is very unstable.

The Fission Process

It transforms into an elongated shape for a short time.

The uranium-236 nucleus formed is very unstable.

The Fission Process

It transforms into an elongated shape for a short time.

It then splits into 2 fission fragments and releases neutrons.

The Fission Process

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

It then splits into 2 fission fragments and releases neutrons.

The Fission Process

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

It then splits into 2 fission fragments and releases neutrons.

The Fission Process

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

It then splits into 2 fission fragments and releases neutrons.

The Fission Process

14156Ba

9236Kr

n 1 0

n 1 0

n 1 0

Nuclear Fission Examples

U235

92 +Ba141

56+ n1

03n

1

0 +Kr 92

36

U235

92 +Cs138

55+ n1

02n

1

0 +Rb 96

37

Energy Released

The energy released can be calculated using the equation:

E = mc2

Where:

E = energy released (J)

m = mass difference (kg)

c = speed of light in a vacuum (3 x 108 ms-1)

E

m c2

Energy from Fission

E = mc2

U235

92 +Cs138

55+ n1

02n1

0 +Rb 96

37

Calculate the energy released from the following fission reaction:

m = 2.65 x 10-28 kg c = 3 x 108 ms-1

E = E

E = 2.65 x 10-28 x (3 x 108)2

E = 2.385 x 10-11 J

Energy from Fission

If one uranium-235 atom undergoes a fission reaction and releases 2.385 x 10-11 J of energy, then the amount of energy released by 1 kg of uranium-235 can be calculated as follows:

total energy = energy per fission x number of atoms

total energy = 2.385 x 10-11 x 2.56 x 1024

total energy = 6.1056 x 1013 J

total energy = 61,056,000,000,000 J

Fat Man & Little Boy

Nuclear Fusion

In nuclear fusion, two nuclei with low mass numbers combine to produce a single nucleus with a higher mass number.

H 2

1 +He 4

2+ n1

0H

3

1 +Energy

The Fusion Process

H 2 1

H 3 1

The Fusion Process

H 2 1

H 3 1

The Fusion Process

H 2 1

H 3 1

The Fusion Process

H 2 1

H 3 1

The Fusion Process

The Fusion Process

The Fusion Process

The Fusion Process

The Fusion Process

He 4 2

n 1 0

ENERGY

The Fusion Process

He 4 2

n 1 0

ENERGY

The Fusion Process

He 4 2

n 1 0

ENERGY

The Fusion Process

He 4 2

n 1 0

ENERGY

Energy from Fusion

E = mc2m = 3.1 x 10-29 kg c = 3 x 108 ms-1

E = E

E = 3.1 x 10-29 x (3 x 108)2

E = 2.79 x 10-12 J

H 2

1 +He 4

2+ n1

0H

3

1 +Energy

The energy released per fusion is 2.79 x 10-12 J.

Fusion – Hydrogen Bomb

The worlds most powerful hydrogen bomb was detonated on the 30th of October 1961. The bomb had an explosive force of 58 megatons, or almost 6,000 times more powerful than the Hiroshima bomb. The bomb was dropped by an aircraft, and detonated 365 meters (1,200 feet) above the surface. The shock wave produced by this bomb was so powerful, it went thrice around the earth.

US Nuclear Triad

In the fast paced, tech-savvy world we live in today, it is easy to disregard the dangers of nuclear warfare. We live in a generation almost 70 years removed from the travesties of the Hiroshima and Nagasaki bombings. However the danger today is far greater than it was 70 years ago. In today's world there are not many countries which do not possess nuclear weaponry. Consider all that you have learned about nuclear chemistry, the films utilized in class (Fat Man and Little Boy & WW2 from Space), and what you have observed and experienced throughout your educational career (especially in the progression of science) to answer the following questions (in proper essay format): What struggles did the scientists face when developing the atomic bomb? (Consider the scientific/technological struggles as well as the possible career acknowledgement and political and societal concerns/backlash – the humanitarian position). What would you have done if you were in their shoes? Do you feel they made the right choices? Explain.

Are you for or against nuclear weaponry? Would you have made the same decisions our country made during WW2? (To make the bomb in the first place; to actually utilize it, etc.) Why? Explain your position. What do think will happen should someone initiate nuclear war? Who would survive? Who do you think would strike first? Why?  What do you think the future holds for a world surrounded by nuclear danger all at the “push of a button”? Will we continue to do what our weaponry makes possible? Will we or have we already “gone too far”? When is enough, enough? Explain you reasoning.