4.7 - fission and fusion reactions

21
Dr Pusey www.puseyscience.com

Upload: grant-pusey

Post on 14-Aug-2015

63 views

Category:

Science


1 download

TRANSCRIPT

Page 1: 4.7 - fission and fusion reactions

Dr Pusey

www.puseyscience.com

Page 2: 4.7 - fission and fusion reactions

Syllabus pointsNeutron‐induced nuclear fission is a reaction in which a

heavy nuclide captures a neutron and then splits into smaller radioactive nuclides with the release of energy

A fission chain reaction is a self‐sustaining process that may be controlled to produce thermal energy, or uncontrolled to release energy explosively if its critical mass is exceeded

Nuclear fusion is a reaction in which light nuclides combine to form a heavier nuclide, with the release of energy

More energy is released per nucleon in nuclear fusion than in nuclear fission because a greater percentage of the mass is transformed into energy

Page 3: 4.7 - fission and fusion reactions

Learning goals Define:

Fission Neutron-induced fission Chain reaction Critical mass

Recall that fission is only possible for two isotopes, Uranium-235 and Plutonium-239

Describe the fission process Describe how the velocity of incoming neutrons can affect the fission

process Compare and contrast controlled and uncontrolled fission reactions Define:

Fusion

Describe the fusion process Explain why the fusion process releases more energy (per nucleon) than

the fission process Compare and contrast energy emission from a fission reaction, fusion

reaction and decay processes

Page 4: 4.7 - fission and fusion reactions

What is Fission? NUCLEAR FISSION occurs when an atomic nucleus

splits into two or more pieces. This is often triggered by the absorption of a neutron. – HP p. 180

Page 5: 4.7 - fission and fusion reactions

Example 1Identify the unknown quantities (A, Z, X, Y) in the fission reactions below.

a) 01𝑛 + 92

235𝑈 → 𝑍𝐴𝑋 + 38

93𝑆𝑟 + 201𝑛

b) 01𝑛 + 92

235𝑈 → 𝑍88𝑋 + 54

𝐴𝑌 + 1201𝑛

c) 01𝑛 + 92

235𝑈 → 3587𝐵𝑟 + 𝑍

143𝐿𝑎 + 𝑥01𝑛

d) 01𝑛 + 92

235𝑈 → 𝑍𝐴𝑋 + 36

92𝐾𝑟 + 301𝑛

Page 6: 4.7 - fission and fusion reactions

Example 1Identify the unknown quantities (A, Z, X, Y) in the fission reactions below.

a) 01𝑛 + 92

235𝑈 → 54141𝑋𝑒 + 38

93𝑆𝑟 + 201𝑛

b) 01𝑛 + 92

235𝑈 → 3888𝑆𝑟 + 54

136𝑋𝑒 + 1201𝑛

c) 01𝑛 + 92

235𝑈 → 3587𝐵𝑟 + 57

143𝐿𝑎 + 601𝑛

d) 01𝑛 + 92

235𝑈 → 56141𝐵𝑎 + 36

92𝐾𝑟 + 301𝑛

Page 7: 4.7 - fission and fusion reactions

Example 2

A typical fission reaction can be seen below:

01𝑛 + 92

235𝑈 → 56141𝐵𝑎 + 36

92𝐾𝑟 + 301𝑛

If there is a loss of mass of 0.215 u calculate how much energy is released from this fission reaction.

Page 8: 4.7 - fission and fusion reactions

Example 2

A typical fission reaction can be seen below:

01𝑛 + 92

235𝑈 → 56141𝐵𝑎 + 36

92𝐾𝑟 + 301𝑛

If there is a loss of mass of 0.215 u calculate how much energy is released from this fission reaction.

Page 9: 4.7 - fission and fusion reactions

Example 3

Calculate the amount of energy released by the fission reaction shown below:

01𝑛 + 92

235𝑈 → 54141𝑋𝑒 + 38

93𝑆𝑟 + 201𝑛

Isotope Mass (u)

Uranium-235 235.043930

Xenon-141 140.92665

Strontium-93 92.914026

Page 10: 4.7 - fission and fusion reactions

Example 3

Calculate the amount of energy released by the fission reaction shown below:

01𝑛 + 92

235𝑈 → 54141𝑋𝑒 + 38

93𝑆𝑟 + 201𝑛

Isotope Mass (u)

Uranium-235 235.043930

Xenon-141 140.92665

Strontium-93 92.914026

Page 11: 4.7 - fission and fusion reactions

Example 4

mass of neutron = 1.674 95 × 10–27 kg,mass of Uranium-235 = 3.903 05 × 10–25 kg,mass of Barium-144 = 2.389 92 × 10–25 kgmass of Krypton-89 =1.476 53 × 10–25 kg

a What is the decrease in the mass of the nuclear particles involved in this fission reaction?b How many joules of energy are released during the fission of this uranium-235 nucleus?c Express the decrease in mass as a percentage of the mass of the initial nuclear particles. d If a 5 kg lump of pure uranium-235 completely underwent fission, how much energy (in joules) would be released?

Page 12: 4.7 - fission and fusion reactions

Example 5

If you build a Nuclear reactor using Uranium 235 (previous slide), how many fission reactions per second are required to power Dr Pusey’s PlayStation 4 (110 Watts)?

Page 13: 4.7 - fission and fusion reactions

ResourcesAV

Tyler DeWitt – Nuclear Fission (8:59)

Crash Course – Nuclear Chemistry (part 2): Fission and fusion (11:18) – Following this slide!

Bang Goes the Theory – Inside a nuclear reactor core (3:52)

ANSTO – OPAL research reactor animation (3:55)

Harvard Lecture Demonstrations – Mousetrap Fission (2:27)

Simulation

Nuclear Fission – pHet simulation

Page 14: 4.7 - fission and fusion reactions

From: http://nuclear.duke-energy.com/2013/01/30/fission-vs-fusion-whats-the-difference/

Page 15: 4.7 - fission and fusion reactions

Example 1Identify the unknown quantities (A, Z, X, Y) in the fusion reactions below.

a) 𝑍2𝐻 + 𝑍

3𝐻 → 𝑍𝐴𝑋 + 0

1𝑛

b) 12𝐻 + 1

𝐴𝐻 → 𝑍3𝑋 + 0

1𝑛

c) 12𝑋 + 2

3𝑌 → 𝑍4𝐻𝑒 + 𝑍

𝐴𝐻

Page 16: 4.7 - fission and fusion reactions

Example 1Identify the unknown quantities (A, Z, X, Y) in the fusion reactions below.

a) 12𝐻 + 1

3𝐻 → 24𝐻𝑒 + 0

1𝑛

b) 12𝐻 + 1

2𝐻 → 23𝐻𝑒 + 0

1𝑛

c) 12𝐻 + 2

3𝐻𝑒 → 24𝐻𝑒 + 2

1𝐻

Page 17: 4.7 - fission and fusion reactions

Example 2

Calculate the amount of energy released by the fusion reaction shown below:

12𝐻 + 1

3𝐻 → 24𝐻𝑒 + 0

1𝑛

Isotope Mass (u)

Deuterium (Hydrogen-2) 2.014101

Tritium (Hydrogen-3) 3.016049

Helium-4 4.002602

Page 18: 4.7 - fission and fusion reactions

Example 2

Calculate the amount of energy released by the fusion reaction shown below:

12𝐻 + 1

3𝐻 → 24𝐻𝑒 + 0

1𝑛

Isotope Mass (u)

Deuterium (Hydrogen-2) 2.014101

Tritium (Hydrogen-3) 3.016049

Helium-4 4.002602

Page 19: 4.7 - fission and fusion reactions

ResourcesAV

PhD Comics – What is fusion, video and simulation (7:56)

Further Reading

Scientific American - Fusion Experiment Breakthrough

Page 20: 4.7 - fission and fusion reactions
Page 21: 4.7 - fission and fusion reactions

How did you go? Define:

Fission

Neutron-induced fission

Chain reaction

Critical mass

Recall that fission is only possible for two isotopes, Uranium-235 and Plutonium-239

Describe the fission process

Describe how the velocity of incoming neutrons can affect the fission process

Compare and contrast controlled and uncontrolled fission reactions

Define:

Fusion

Describe the fusion process

Explain why the fusion process releases more energy (per nucleon) than the fission process

Compare and contrast energy emission from a fission reaction, fusion reaction and decay processes