1. ET 10.17 It is December of 1957 – 12 ½ years after the bombings of Hiroshima and Nagasaki, and it’s just been announced that the US has opened its first commercial nuclear power plant in Beaver Country, PA. Describe your reactions.

2. Nuclear Power: From Bombs to Everyday Energy Unit 1 Lesson 14

3. From Bombs to Energy When people hear the words… “Uranium” “Radiation” “Nuclear Energy” What do think often think of? Can nuclear energy safely be put to good use? Decide for yourself! But first, learn how it works!

4. The Beginning: Fission Nuclear fission gives off energy: –What if we could use that energy to power cities! Two fissile fuel options: –Uranium 235 –Plutonium 239

5. But… Fissile Atoms Make Bombs! Remember – weapons grade Uranium is enriched until it contains: 80% Uranium-235 The Uranium for a nuclear power plant contains only: 2-3% Uranium-235 Uranium-235: The fissile (but RARE) isotope of Uranium.

6. Chain Reactions Atomic Bomb: want at least a critical mass to begin chain reaction. Goal: Out of control chain reaction! Nuclear Reactor: want to be at critical mass, not more, to begin chain reaction. Goal: Control the chain reaction! How can we “control” the chain reaction?

7. How reactors work Fuel: –2.5 cm pellets, put into rods. Control Rods: –Neutron Absorber! –Prevent overheating, keep chain reaction under control. Moderator: –Helps keep the fission reaction under control. Absorbs extra heat and energy. –Graphite

10. How reactors work Coolant: –Take heat energy from reaction and carry it out of the reactor. –Shouldn’t absorb neutrons… or else it would stop the chain reaction. –Should be able to absorb lots and lots of heat.

11. Where does the *hot* coolant go?

12. Nuclear Waste: Radioactive Trash! “Spent nuclear fuel” –Leftovers from fuel rods. –Still radioactive! Emits α, β, and γ radiation! Can contaminate food, water, air… BAD NEWS Worldwide annual nuclear fuel waste: 26 million pounds!

14. Yucca Mountain, Nevada

15. Working since 1987 to prepare Yucca Mountain to be the national “underground garbage dump” for spent nuclear fuel. Lots of challenges, still not in use. Obama: Yucca Mountain no longer being considered for spent fuel: will need more than one site.

16. Nuclear Power Around the World

18. Nuclear Power: Pros and Cons Pros No greenhouse gas emissions! Only need very little uranium. A single plant can create huge amounts of energy. There are large uranium deposits in Canada and Australia Cons Radioactive waste We haven’t found much uranium in the world. Potential radiation exposure or explosion if there is an accident. Security risks.

19. HW – Due Wed. Oct 19 th DN Vocab –Nuclear Reactor –Control Rods –Moderator Reactor Diagram (instructions on sheet).

20. Exit Ticket What assumptions did you make about nuclear power when you wrote your entrance ticket? Has your opinion of nuclear power changed now that you know how a nuclear power plant works? Why or why not?