Please sit together in pairs: Mike A. and Joe Serruto Barney and Yiran Thomas and Steve T.

Mikhail and Evan • Valerie and Rebecca • Kevin and Katherine • Ally and Joe Sebek • Matt M. and Quanbiao • Morgan and Charlie • Laura and Lu • Lauren and Ashkan • Mikey O. and Naichen • Hannah and Dale • Jim and Disha • Nick and Efrain • Ben and Da • Nik and Heran • Please sit together in pairs: • Mike A. and Joe Serruto • Barney and Yiran • Thomas and Steve T. • Glenn and Joey B. • Ann and Johnny • Grant and Stephen H. • Korey and Qihan • Will and Nicole • Michael W. and Ed • Zach and Zhenmin • Casey and Taehoon • Audrey and Shenheng • Lisette and Matt R. • Erica and Andrea Phys 150 Lecture 11

Announcements • Exam 1 is Thursday, October 4, in class. Multiple choice and written-answer questions (like homework). Exam covers Chapters 1-5. • Practice Exam is posted on the web page. • Quiz and Homework solutions are posted. • Read Chapter 6 for Tuesday, October 9. There will be a quiz in class. • There is no homework due on Monday, October 8. Phys 150 Lecture 11

Nuclear Reactors and Bombs • Fission • n + 235U  2 fission fragments + 2 n + Energy • n + 239Pu  2 fission fragments + 3 n + Energy • Fusion • D + T  4He + n + Energy • Basic reactions for a nuclear bomb or a nuclear reactor D = pn T = pnn 4He = ppnn Phys 150 Lecture 11

i>clicker question The main reason it is hard to get D and T to fuse together is • they are repelled by the electric force • they are repelled by the strong force • they have excess neutrons • All of the above Phys 150 Lecture 11

i>clicker question The main reason it is hard to get D and T to fuse together is • they are repelled by the electric force • they are repelled by the strong force - attracted • they have excess neutrons – this helps attract • All of the above Phys 150 Lecture 11

i>clicker question D is obtained • from deep wells • from the atmosphere • from water • from a breeder reactor Phys 150 Lecture 11

i>clicker question D is obtained • from deep wells • from the atmosphere • from water –1 part in 6000 of H is D • from a breeder reactor Phys 150 Lecture 11

i>clicker question T is obtained • from Lithium • from D • from water • from a breeder reactor Phys 150 Lecture 11

i>clicker question T is obtained • from Lithium –n + 6Li  T + 4He + Energy • from D • from water • from a breeder reactor 6Li = pppnnn Phys 150 Lecture 11

i>clicker question The ITER will generate power from fusion using a DT gas at • low pressure • low temperature • high density • All of the above Phys 150 Lecture 11

i>clicker question The ITER will generate power from fusion using a DT gas (actually a plasma) at • low pressure –don’t want explosion • low temperature – need high T for fusion • high density – low density (see A.) • All of the above ITER = International Thermonuclear Experimental Reactor (France, 2018) Phys 150 Lecture 11

ITER Phys 150 Lecture 11

Fukushima disaster 2011 Boiling Water Reactor (BWR) Fukushima 2011 Phys 150 Lecture 11

i>clicker question Waste from a nuclear reactor is mostly • Fission fragments • 238U • 235U • 239Pu Phys 150 Lecture 11

i>clicker question Waste from a nuclear reactor is mostly • Fission fragments – 4% • 238U - because that’s what most of the “fuel” is • 235U – 1% • 239Pu – 1% Phys 150 Lecture 11

Nuclear waste • Radioactivity ratio (not including 239Pu) • 100 after 100 years • 1 after 10,000 years Phys 150 Lecture 11

Please sit together in pairs: Mike A. and Joe Serruto Barney and Yiran Thomas and Steve T.