CHEE2695 – Lecture 16
Nuclear energy:
- Involves the modification of the nucleus of an atom.
o Atomic bonds, not chemical bonds.
Fission technology:
- Fission is implemented by smashing a heavy nucleus with a nucleon of the
right energy.
- Several isotopes are commonly used:
- The fission process splits the heavy atom into smaller fragments.
- Neutrons initially released from spontaneous fission of the fuel or from a
neutron source are known as thermal neutrons.
o The neutron must have the right speed to combine with the fissile
material.
o Fast moving neutrons can be slowed or stopped by collisions with a
lighter atom.
o Neutron moderators are used to stop uncontrolled reactions.
Fissile materials:
- A small amount of mass is converted to energy according to E=mc 2.
- Bombs can be created by a runaway nuclear reaction.
- Accidents can occur by creating a large pressure in the reactor, leading to an
explosion.
- One kg of U235 can create as much energy as 3 000 000 kg of coal.
- It is non-renewable, but small reserves can create very large amounts of
energy.
- Zero greenhouse gas emissions but has other issues.
Nuclear accidents and bombs:
- If control rod assembly gets too hot, metals can melt, radioactive material can
heat out of control.
- Reactors must be kept cool, or high temperatures can rupture the
containment vessel.
- Nuclear bombs intentionally use runaway nuclear reactions.
Nuclear energy:
- Involves the modification of the nucleus of an atom.
o Atomic bonds, not chemical bonds.
Fission technology:
- Fission is implemented by smashing a heavy nucleus with a nucleon of the
right energy.
- Several isotopes are commonly used:
- The fission process splits the heavy atom into smaller fragments.
- Neutrons initially released from spontaneous fission of the fuel or from a
neutron source are known as thermal neutrons.
o The neutron must have the right speed to combine with the fissile
material.
o Fast moving neutrons can be slowed or stopped by collisions with a
lighter atom.
o Neutron moderators are used to stop uncontrolled reactions.
Fissile materials:
- A small amount of mass is converted to energy according to E=mc 2.
- Bombs can be created by a runaway nuclear reaction.
- Accidents can occur by creating a large pressure in the reactor, leading to an
explosion.
- One kg of U235 can create as much energy as 3 000 000 kg of coal.
- It is non-renewable, but small reserves can create very large amounts of
energy.
- Zero greenhouse gas emissions but has other issues.
Nuclear accidents and bombs:
- If control rod assembly gets too hot, metals can melt, radioactive material can
heat out of control.
- Reactors must be kept cool, or high temperatures can rupture the
containment vessel.
- Nuclear bombs intentionally use runaway nuclear reactions.
