The key difference between fissile and fertile isotopes is that fissile isotopes are material that can undergo fission reaction, whereas fertile isotope is a material that can be converted into a fissile isotope.
The terms fissile isotope and fertile isotope come under the category of nuclear chemistry. they define two different types of atoms that have different numbers of neutrons with the same number of protons in their nuclei (isotopes) which are radioactive. There are two major types of nuclear reactions as fission reaction and fusion reaction. These fissile isotope and fertile isotope are useful regarding fission reactions.
CONTENTS
1. Overview and Key Difference
2. What are Fissile Isotopes
3. What are Fertile Isotopes
4. Side by Side Comparison – Fissile vs Fertile Isotopes in Tabular Form
5. Summary
What are Fissile Isotopes?
Fissile isotopes are atoms that can undergo fission reactions. These are also named as fissionable materials. Some well-known fissile materials include Uranium-235, Plutonium-239, and Uranium-233. However, among these three species, only Uranium-235 occurs naturally while the other two are synthetic chemical species formed from Uranium-238 and Thorium-232, respectively.
Figure 01: Plutonium Isotope
U-235 is an isotope of the chemical element Uranium, which is composed of 92 protons and 143 neutrons in its nucleus. The chemical symbol for Uranium is given as 23592U. The natural abundance of U-235 is about 0.72%. The mass of this isotope is about 235.043 amu.
Plutonium is an artificial chemical element that has the atomic number 94 and symbol Pu. In the periodic table of elements, Plutonium can be found in the actinide series among f block elements. At room temperature and pressure, it is in the solid-state. The electron configuration of this element can be given as [Rn]5f67s2. Therefore, it has six electrons in the f orbital.
What are Fertile Isotopes?
Fertile isotopes are atoms that can convert into fissile isotopes. These fertile isotopes cannot undergo fission themselves because they have neutrons with low energy. They can undergo fission only by converting themselves into fissile isotopes. Some common examples of naturally occurring fertile isotopes include Thorium-232 and Uranium-238. These two are the only naturally occurring fertile isotopes.
Figure 02: Conversion of Fertile Isotopes into Fissile Isotopes
The conversion of fertile isotopes into fissile isotopes is done through irradiation of isotopes inside nuclear reactors. Here, neutrons are combined with these isotopes to make them fissile. After this conversion, newly formed fissile material can undergo radioactive decay. When Thorium-232 and Uranium-238 are converted into fissile isotopes, these isotopes become Plutonium-239 and Uranium-233, respectively.
What is the Difference Between Fissile and Fertile Isotopes?
The key difference between fissile and fertile isotopes is that fissile isotopes are material that can undergo fission reaction, whereas a fertile isotope is a material that can be converted into a fissile isotope. Moreover, fissile isotopes can undergo fission reactions directly, while fertile isotopes cannot undergo fission directly. Uranium-235, Plutonium-239, and Uranium-233 are examples of fissile isotopes while Thorium-232 and Uranium-238 are examples of fertile isotopes.
The following table summarizes the difference between fissile and fertile isotopes.
Summary – Fissile vs Fertile Isotopes
The terms fissile isotope and fertile isotope are used mainly in nuclear chemistry. The key difference between fissile and fertile isotopes is that fissile isotopes are material that can undergo fission reaction, whereas a fertile isotope is a material that can be converted into a fissile isotope.
Reference:
1. “Fissile Material.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 30 July 2015, Available here.
2. “Fertile.” Fertile – Energy Education, Available here.
3. “Fertile Material.” Wikipedia, Wikimedia Foundation, 25 Nov. 2019, Available here.
Image Courtesy:
1. “Plutonium pellet” By Department of Energy – (Public Domain) via Commons Wikimedia
2. “Sasahara” By Original uploader was JWB at en.wikipedia – Transferred from en.wikipedia (CC BY-SA 3.0) via Commons Wikimedia