SCI 270: On Nuclear Technology Practice Problems

## 8. Nuclear Reactions

1. Is the reaction 14N + 4He ® 17O + 1H, endothermic or exothermic? Evaluate the energy, Q, of the reaction. Give this amount of energy per nuclear reaction and per mole of reactants.
Masses: H, 1.007825; n, 1.008665; He, 4.00260; 14N, 14.00307; and 17O, 16.99914.
Conversion factor and constant: 1 amu = 1.66053e-27 kg, c = 3.0e8 m s-1 (velocity of light).

 The reaction14N (a, p) 17O is _____-thermic Q = ___________ MeV/reaction    = ___________ J/mol

2. Is the reaction 14N (n, p) 14C endothermic or exothermic? What is the mass of 14C if the beta decay energy is 0.156 MeV? Calculate the energy of the N (n, p) C reaction.

 The reaction14N (n, p) 14C is _____-thermic Mass of 14C = ____________ amu Q = ___________ MeV/reaction

3. Complete the following reaction by giving the symbol of the products.

 14B ( , b) ________ 18N ( , b a) ________ 9Be (6Li, p) ________ 9Be (7Li, d) ________ 11B (a, p) ________ 12C (a, 2p) ________ 12C (t, p) ________ 13C (d, p) ________ 13C (t, d) ________

Notes: a = 4He, b = 0e-, p = 1H, d = 2D, t = 3T.

4. Cobalt has only one stable isotope, 59Co, whose atomic mass is 58.9332 amu. According to the Handbook of Chemistry and Physics, the cross sections for the reaction 59Co (n, g) 60 mCo reaction is 20 b; the cross sections for the reaction 59Co (n, g) 60Co reaction is 17 b; the half life of 60mCo ( , g)60Co is 10.5 m; the half life of 60Co ( , b (followed by g)) 60Ni is 5.26 y; and the decay energy of 60Co 2.819 MeV. Estimate the amount of each produced, including those nuclei that have decayed during the time when 59.0 g of 59Co is irradiated by neutrons with an intensity of 1.0e15 neutron cm-2 s-1 in a nuclear reactor for 60 seconds. Assume all nuclei begin to decay after the irradiation is finished. Estimate the number of nuclei left after 24 hours.

Reaction Cross
section
Number of
nuclei produced
Number of Nuclei
remain after 24 hours
59Co (n, g) 60 mCo 20 b
__________

__________
59Co (n, g) 60Co 17 b
__________

__________

5. What are transuranium elements and transactinide elements? Give two nuclear reaction equations, one for the synthysis of a transuranium element, and one for the synthesis of a transactinide element. Explain your nuclear reactions for their synthesis.

 Reaction for the synthesis of a transuranium element __________________ Reaction for the synthesis of a transactinide element __________________

6. Why neutrons are the most important particles for the induction of nuclear reactions? What is a neutron source? What methods have been used to produce neutrons as neutron sources? What feature(s) shall be considered regarding the selection of a neutron source and why?