Lecture 11 Nuclear Physics Part 3

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Fyu02- Kvantfysik. David Milstead. Lecture 11. Nuclear Physics Part 3. Nuclear Reactions. Fission. Nuclear Reactor. Fusion ...
Lecture 11 Nuclear Physics Part 3 Nuclear Reactions Fission Nuclear Reactor Fusion

Fyu02- Kvantfysik David Milstead

Nuclear Reactions Radioactivity will convert one nuclide into another. We can artificially do this in the lab via nuclear reactions Eg, first artificially induced transmutation (1919) 4 2

α +

14 7

N→

17 8

O + 11 p

General form of a nuclear reaction in which particle a, interacts with nucleus X, producing particle b and nucleus Y.

a+X→ Y +b Fyu02- Kvantfysik David Milstead

Reaction energy Q, determined by mass difference between the initial and final sets of particles Q = ∆mc2 = (ma + mX − mY − mb )c 2

(11.1)

If Q>0, reaction is exothermic (energy released as kinetic energy and γ-rays) If Q108 K) at which atoms are stripped of electrons and ionised gas is a plasma. :high particle density (n particles/vol) :long confinement time τ to allow reaction to occur Fyu02- Kvantfysik Lawson’s criteria nτ>1020 s/m3 (11.2) David Milstead 2 1

Fusion in the Lab. Joint European Torus (JET): the world’s largest nuclear fusion research facility, Oxford Uk. Plasma confined by magnetic field and heated to temperatures of 40-50 million degrees. As yet, no success in producing a net surplus of usable energy (always 10 years away!).

Fyu02- Kvantfysik David Milstead

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