Applications of nuclear reactions

Nuclear reactions
  • produce new nuclides or elements,
  • release energy,
  • and produce subatomic particles.

    These features can be applied to

  • scientific investigations,
  • engineering projects,
  • medical diagones and treatments,
  • and biological experimentations.

    Let your imagination stretch and apply nuclear reactions to benefit you and your society.

    In the past, nuclear reactions have been applied to solve some scientific pussles, and further research and development have made many benefitial applications.

    The following applications are based on nuclide productions.

    The Synthesis of Technetium, Tc

    The missing element
    between Mo and Ru.
    V Cr Mn Fe Co
    Nb Mo __ Ru Rh
    Ta W Re Os Ir
    The element with atomic number 43 was not found anywhere on Earth. In 1937, C. Perrier and E. Segré increased the atomic number of Mo by bombarding it with cyclotron accelerated deuterium: 96Mo (2D, n) 97Tc Isotope 97Tc has a half life of 2.6 million years. Other long-lived isotopes are 98Tc (4.2 million years), and 99Tc (0.2 million years). In general, technetium isotopes are made by the reaction, Mo42 (n, b) Tc42 or from the fission products of uranium or plutonium. Some kilograms of 99Tc have been isolated from processing nuclear fuels.

    The isomer 99mTc is widely used in nuclear medicine for the following reasons:

    For thyroid scanning, 99mTc solution is injected into patients. After 20-40 minutes, 99mTc is trapped in the thyroid, and images can be obtained. Oral taking of 123 or 131I requires 6 to 24 hours.

    Thyroid imaging is useful in evaluating the location, approximate size, anatomy, and functional status of the thyroid gland. This is especially helpful for thyroid nodules, multinodular goiter, thyroiditis, and possible ectopic thyroid tissue (eg, lingual or mediastinal).

    The Synthesis of Astatine, At

    A portion of the
    periodic table.
    Sn Sb Te I Xe
    Pb Bi Po __ Rn
    The element below iodine and between Po and Rn was unknown until D.R. Corson, K.R. Mackenzie and E. Segré synthesized it using the reaction 209Bi83 (a, x n) (213-x)At85 The reaction releases x (= 1, 2, or 3) number of neutrons. In 1940, they made the missing element and called it astatine, At, after the Greek word astatos meaning unstable.

    They irradiated bismuth sheets by a particles hoping to increase the atomic number by 2. They assumed the element be similar to iondine from its position on the periodic table. Thus, they heat the bismuth sheet and the isotopes of astatine sublimated, and condensed on a cold surface.

    Knowing the properties of some astatine isotopes enable the detection of natural astatine isotopes. Todate, almost 20 astatine isotopes have discovered or made, with 210At having the longest half-life of 8.3 h.

    Neutron Activation Analysis (NAA)

    Neutron Activation Analysis (NAA) is an important application of of nuclear reactions.

    Neutron activation analysis is a multi-, major-, minor-, and trace-element analytical method for the accurate and precise determination of elemental concentrations in a materials.

    Sensitivity for certain elements are below nanogram level.

    The method is based on the detection and measurement of characteristic gamma rays emitted from radioactive isotopes produced in the sample upon irradiation with neutrons.

    High resolution germanium semiconductor detector gives specific information about elements.

    Some 60 elements are routinely analyzed by the NAA center in Cornell University. It analyzed samples from agriculture, geology, medicine, to oceanography, serving various discipline and industries.

    There are other centers carying out routine NAA servies for their clients too.

    General Activation Analysis, Inc is a business that has analyzed tens of thousands samples since 1973. The sensitivities of various elements of the periodic table are given by this company.

    The Safe LOW POwer Kritical Experiment SLOWPOKE reactor in the University of Toronto has an on site gamma-ray spectrometer for instrumental neutron activation analysis. This is part of a flexible network of inter-university and international co-operative research projects.

    McMaster Nuclear Reactor (MNR) began operating in 1959 as the first university based research reactor in the British Commonwealth. It offers the following services

    Example 1

    Solution

    E-mail: cchieh@uwaterloo.ca