Commerial radioisotopes and Transuranic elements. (1 Viewer)

[Nissanist]

2 syllabus dot points asks u how transuranic and commercial radioisotopes are produced, but i can't seem to find any text book that clearly descibes the difference between them and how they are produced. Any help?

 

[Dreamerish*~]

2 syllabus dot points asks u how transuranic and commercial radioisotopes are produced, but i can't seem to find any text book that clearly descibes the difference between them and how they are produced. Any help?

The difference is that commercial radioisotopes are not necessarily transuranic radioisotopes. Transuranic radioisotopes are defined as isotopes of elements which have a higher atomic number than 92, which is uranium - hence the name, transuranic. Some commercial radioisotopes such as technitium-99m (atomic number of 43) and cobalt-60 (atomic number of 27) are not transuranic.

Production of Transuranic Radioisotopes:
Transuranic (or transuranium) radioisotopes are those following uranium in the periodic table. Since uranium is the heaviest occurring element on earth, transuranic elemetns must be produced synthetically. Neptunium and plutonium were first synthesised in 1940 by bombarding uranium-238 with neutrons as shown in the equations below:

²³⁸₉₂U + ¹₀n → ²³⁹₉₂U → ²³⁹₉₃Np + ⁰_-1e

²³⁸₉₃Np → ³⁹₉₄Pu + ⁰_-1e

Other transuranic elements have been synthesised by bombarding the nuclei of heavy elements with the nuclei of other atoms. Some examples of preparation of transuranic elements are:

Americium: ²³⁹₉₄Pu + ¹₀n → ²⁴⁰₉₅Am + ⁰_-1e

Neptunium: ²³⁸₉₂U + ¹₀n → ²³⁹₉₃Np + ⁰_-1e

This is how elements with atomic numbers of larger than 92 are synthesised.

Production of Commercial Radioisotopes:
ANSTO produces commercial radioisotopes for use in industry, medicine and research. ANSTO operates the research reactor called HIFAR (High Flux Australian Reactor) at Lucas Heights in Sydney and the National Medical Cyclotron near Royal Prince Alfred Hospital, Sydney. Neutron-rich radioisotopes are produced at the nuclear reactor and neutron-deficient radioisotopes are produced in the cyclotron.
The HIFAR reactor has been designed to produce a source of neutrons rather than for the generation of electricity. The fission of uranium-235 (bombarding the atom with neutrons or other particles to separate the atom into two smaller atoms) produces neutrons with which to bombard the nuclei of stable elements. The same to be irradiated is placed in the core of the reactor where it absorbs neutrons and is transformed into a radioactive daughter nuclide.
An example of a commercial radioisotope is technetium-99m. Molybdenum-98 undergoes neutron bombardment to form molybdenum-99 which then undergoes beta decay to form technetium-99:

⁹⁸₄₂Mo + ¹₀n → ⁹⁹₄₂Mo

⁹⁹₄₂Mo → ⁹⁹₄₃Tc + ⁰_-1e

Hope it helped.

 

[Nissanist]

yeh thanks, that explained everything. Thanks heaps