Lec16+Energy+III - Energy Chemistry and Society III Chapter...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Energy, Chemistry and Society III Chapter 7, Sections 7.1-7.3 and 7.9-7.11 (Nuclear Energy)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Basic Principle: Nuclei fall apart (nuclear fission) to release energy   Energy n Kr Ba U n U 1 0 92 36 141 56 236 92 1 0 235 92 3 Characteristics of a nuclear reaction 1. In a nuclear reaction: total number of protons+neutrons conserved, but… total number atoms is not 2. Mass on left hand side Mass on right hand side, but: 3. Mass on left hand side Mass on right hand side, and: 4. Mass on left hand side > Mass on right hand side 5. Mass change (loss) 0.1% (1/1000th) 6. E = mc 2 Since the mass decreases slightly, an equivalent amount of energy is released!
Background image of page 2
Nuclear vs. Combustion Reactions Combustion of 1 kg CH 4 releases 5x10 4 kJ This energy equals the energy needed to operate one 100 W light bulb for about 5 days. Fission of 1 kg of 235 U releases about 9x10 10 kJ This energy equals the energy needed to operate 2 million 100 W light bulbs for 5 days!
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chain reaction: Requires a neutron to start the process (initiator) Self-propagating once the reaction is started because several neutrons are released per neutron “reacted” Highly enriched 235 U (up to 90% of total U) is capable of very fast propagation (i.e. nuclear explosion) 235 U in reactors is typically 3-5% of total U   Energy n Kr Ba U n U 1 0 92 36 141 56 236 92 1 0 235 92 3
Background image of page 4
Electricity production from a nuclear reactor: similar principle to a combustion facility
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
The “core” of a nuclear reactor Control rods made of cadmium (absorbs neutrons) Primary coolant = Boric acid in water (H 3 BO 3 ) Boron absorbs neutrons and helps slow reaction Fuel = 235 U (in form of UO 2 ) Initiator = 238 Pu or 9 Be (generates neutrons) Packed into pellets
Background image of page 6
Assists in the
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 29

Lec16+Energy+III - Energy Chemistry and Society III Chapter...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online