How is nuclear energy harnessed to generate electricity...?
Interactive Study Guide
false
true
Guiding Question 27.3
How is nuclear energy harnessed to generate electricity in a fission reactor?
Why You Should Care
Nuclear energy releases radiation constantly as it decays. This decay can be sped up by packing more radioactive isotopes into smaller and smaller volumes. The released neutrons strike nearby isotopes, and this speeds their decay. This creates a chain reaction of more isotopes decaying and brings radiation up to levels that are usable for power generation.
Reactors control chain reactions by inserting control rods that capture neutrons and slow chain reactions. By slowly removing the control rods, chain reactions of fission increase and release more heat that is used to boil water directly (boiling water reactor, or BWR) or indirectly (pressure water reactor, or PWR).
As long as the boiling water is cooled enough, the water can be recirculated back to absorb more heat from the reactor. The greatest fear of any reactor is a failure to cool water and the reactor beginning to overheat. If the overheating cannot be stopped, the reactor will “melt down” as fission goes out of control and the reactor fails. Numerous safety procedures and backups must be included to ensure this never happens.
Question 1 of 5
1.
Click the area in the diagram that represents the term neutron.
Nuclear fission uses chain reactions to speed up decay. What is the source of the neutrons?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
7.
Why are these reactions called chain reactions?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
8.
Why would reactors need other neutrons hitting the uranium nuclei to speed the reaction?
Each radioactive nucleus will eventually decay on its own, but the neutrons speed up the reaction. Since each decay releases 2–3 neutrons, every nucleus can potentially cause the decay of 2 or 3 other nuclei faster (rather than waiting for natural decay).
9.
Why is water important for both pressure water reactors (PWRs) and boiling water reactors (BWRs)?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
10.
What is the main difference between PWRs and BWRs?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
11.
What is the normal operative temperature for both PWRs and BWRs?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
12.
What is the role of the condenser?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
13.
How do we slow down chain-reaction fission inside the fuel assemblies?
A.
B.
C.
D.
999
Try again.
Correct.
Incorrect.
14.
Runaway nuclear reactions (meltdowns) occur when not enough water is available to cool fuel rod assemblies and keep them from melting. What would be the effect if the fuel rods melted?