Lesson to students of Tomsk Polytechnic Univercity

1. General terms in nuclear
safety and security sphere.
Nuclear fuel cycle (NFC)
Ekaterina Sviridova

2. Purpose and objectives
Development ofYOUR ability to use English inYOUR professional sphere.
You will:
• obtain information from foreign resources;
• use computer in scientific research;
• work in team;
• analyze problems and risks in professional sphere;
• ready to make a decision in difficult situation;
• fluently discuss in English.

3. Define following terms:
•Proton
•Attractive force
•Half-life

4. Define following terms:
•Nuclei
•Binding energy
•Activity

5. Define following terms:
•Neutron
•Isotope
•Absorption

6. The history of nuclear physics
It can be divided into three periods:
• The first begins with the discovery radioactivity of the nucleus and ends in
1939 with the discovery of fission.
• The second period from 1947 to 1969 saw the development of nuclear
spectroscopy and of nuclear models.
• The third period from 1970 to nowadays.

7. The main stages of this first period of nuclear
physics are the following:
• 1868 Mendeleev’s periodic classification of the elements.
• 1895 Discovery of X-rays by Roentgen.
• 1896 Discovery of radioactivity by Becquerel.
• 1897 Identification of the electron by J.J.Thomson.
• 1898 Separation of the elements polonium and radium by Pierre and Marie
Curie.
• 1908 Measurement of the charge +2 of the α particle by Geiger and
Rutherford.
• 1911 Discovery of the nucleus by Rutherford; “planetary” model of the atom.

8. • 1913Theory of atomic spectra by Niels Bohr.
• 1914 Measurement of the mass of the α particle by Robinson and
Rutherford.
• 1924–1928 Quantum theory (de Broglie, Schr¨odinger, Heisenberg, Born,
Dirac).
• 1928 Theory of barrier penetration by quantum tunneling, application to α
radioactivity, by Gamow, Gurney and Condon.
• 1929–1932 First nuclear reactions with the electrostatic accelerator of
Cockcroft andWalton and the cyclotron of Lawrence.
• 1930–1933 Neutrino proposed by Pauli and named by Fermi in his theory of
beta decay.
• 1932 Identification of the neutron by Chadwick.

9. • 1934 Discovery of artificial radioactivity by F. and I. Joliot-Curie.
• 1934 Discovery of neutron capture by Fermi.
• 1935 Liquid-drop model and compound-nucleus model of N. Bohr.
• 1935 Semi-empirical mass formula of Bethe andWeizsacker.
• 1938 Discovery of fission by Hahn and Strassman.
• 1938 Bethe and Weizsacker propose that stellar energy comes from
thermonuclear fusion reactions.
• 1939Theoretical interpretation of fission by Meitner, Bohr andWheeler.
• 1946 Gamow develops the theory of cosmological nucleosynthesis.

10. The main stages of the second period of
nuclear physics are the following:
• 1953 Salpeter discovers the fundamental solar fusion reaction of two
protons into deuteron.
• 1957 Theory of stellar nucleosynthesis by Burbidge, Burbidge, Fowler and
Hoyle.
• 1960– Detection of solar neutrinos

11. Remember some nuclear discoveries that take
place in the third period

12. Half-life (t1⁄2)
is the amount of time required for the amount of something to fall to half its
initial value. The term is very commonly used in nuclear physics to describe
how quickly unstable atoms undergo radioactive decay, but it is also used
more generally for discussing any type of exponential decay.
The original term, dating to Ernest Rutherford's discovery of the principle in
1907, was "half-life period", which was shortened to "half-life" in the early
1950s.

13. Half-life (t1⁄2)
Half-life is used to describe a quantity undergoing exponential decay, and is
constant over the lifetime of the decaying quantity. It is a characteristic
unit for the exponential decay equation. The term "half-life" may generically
be used to refer to any period of time in which a quantity falls by half, even if
the decay is not exponential. The table on the right shows the reduction of a
quantity in the number of half-lives elapsed.

14. Half-life (t1⁄2)
• An exponential decay process can be described by
any of the following three equivalent formulas:
• The three parameters are all directly related in the
following way:

15. Half-life (t1⁄2)
• By plugging in and manipulating these relationships, we get all of the
following equivalent descriptions of exponential decay, in terms of the half-
life:

16. Half-life (t1⁄2)

17. Half-life (t1⁄2)
Simulation of many identical atoms undergoing
radioactive decay, starting with either 4 atoms per box
(left) or 400 (right). The number at the top is how many
half-lives have elapsed. Note the consequence of the law
of large numbers: with more atoms, the overall decay is
more regular and more predictable.

18. For any radioactive material, its half-life…
a. …first decreases and then increases.
b. …first increases and then decreases.
c. …increases with time.
d. …decreases with time.
e. …stays the same.

19. After 6 seconds, the mass of a sample of
radioactive material has reduced from 100
grams to 25 grams.
•Its half-life must be ….?

20. Define the following stages of NFC.
Describe physical and chemical processes that take
place inYOUR process.Tell about facilities that
performYOUR stage in Russian Federation.

21. •Exploration;
•Mining;
•Milling;
•Conversion;
•Enrichment;
•Fabrication;
•Power Plant;
•Spent fuel storage;
•Final disposal;
•Reprocessing;
•Vitrification;
•Recycle.

22. Work in groups to find the most nuclear theft
attackable stage of NFC

23. Let your groups discuss between each other
trying tern to your opinion about the most nuclear
theft attackable stage of NFC

24. Give a description of the following isotope:
•Pu236;
•U233;
•Am241;
•Th232

25. A certain radioactive material has a half-life of 8
minutes. Suppose you have a large sample of this
material, containing 1025 atoms.
• a. How many atoms decay in the first 8 minutes?
• b. Does this strike you as a dangerous release of radiation? Explain.
• c. How many atoms decay in the second 8 minutes?
• d.What is the ratio of the number of atoms that decay in the first 8 minutes
to the number of atoms that decay in the second 8 minutes?
• e. How long would you have to wait until the decay rate drops to 1% of its
value in the first 8 minutes?

26. Homework assignment
Find a way to thieve nuclear material on the one of
the NFC stage.

27. Thank you for your
attention!