Page 68 - Radiochemistry and nuclear chemistry

Nuclear Mass and Stability 57

3.3. Assuming that in the fission of a uranium atom an energy amount of 200 MeV is released, how far would
1 g of 235U drive a car which consumes 1 liter of gasoline (density 0.70 gcm -3) for each 10 km? The combustion
heat of octane is 5500 kJ mole -l, and the combustion engine has an efficiency of 18%.
3.4. Estimate if fusion of deuterium into helium releases more or less energy per gram of material consumed than
the fission of uranium.
3.5. When a neutron is captured in a nucleus, the mass number of the isotope increases one unit. In the following
Table mass excess values are given for three important isotope pairs:

235U 40 915 keV ~ 42 441 key
23Su 47 306 239U 50 5 71
239Pu 48 585 ~~ 50 122
If the average nucleon binding energy in this region is 7.57 MeV one can calculate the difference between this
average binding energy and the one really observed in the formation of ~, 23913, and 2~u. Calculate this
difference. Discuss the possible significance of the large differences observed for the ~SU/~gU pair as compared
to the other pairs in terms of nuclear power.
3.6. With the semiempirical mass equation 0.8) estimate the binding energy per nucleon for l~ 27A1, 59Co,
and 2~6U. Compare the results with the observed values in Table 3.1.
3.7. With eqn. (3.10) determine the atomic number corresponding to maximum stability for A = 10, 27, 59, and
239. Compare these results with the data in the isotope chart, Appendix C.

3.11. Literature

R. D. EW~NS, The Atomic Nucleus, McGraw-Hill, 1955.
B. S. DZHELF_YOV and L. K. PEKER, Decay schemes of radioactive nuclei, Pergamon Press, 1961 (though grossly
out-of-date, it is still useful as a source of simple decay schemes).
W. D. MYERS and W. J. SWIATEOrd, Nuclear Masses and Deformations, Nucl. Phys., 81 (1966) 1.
A. H. WAJ's'rRA and G. AUDI, The 1983 Atomic Mass Evaluation, Nucl. Phys., A432 (1985) 1.
E. BROWNE and R. B. FreEStONE, V. S. SHIRLEY (F,d.), Table of Radioactive Isotopes, J. Wiley & Sons, 1986.
K. S. KRANE, Introductory Nuclear Physics, J. Wiley & Sons, 1988.
Nuclides and Isotopes, 14th Ed., General Electric Company, Nuclear Energy Operations, 175 Curtner Ave.,
M/C397, San Jose, CA 95125, USA, 1989.
R. B. FreESTONE, Table oflsotopes, 8th Ed., J. Wiley & Sons, 1996.