Question

Breeder reactors are used to convert the nonfissionable nuclide \({ }_{92}^{238} \mathrm{U}\) to a fissionable product. Neutron capture of the \({ }_{92}^{238} \mathrm{U}\) is followed by two successive beta decays. What is the final fissionable product?

Short answer

The final fissionable product formed from the neutron capture and two successive beta decays of \(_{92}^{238} \mathrm{U}\) is \(_{94}^{239} \mathrm{Pu}\) (Plutonium).

Step-by-step solution

Determine the isotope formed after neutron capture

: When a nuclide captures a neutron, its mass number increases by 1 while its atomic number remains the same. The captured neutron increases the number of neutrons by 1. So the isotope after neutron capture will be \(_{92}^{239} \mathrm{U}\).

Determine the first isotope formed after the first beta decay

: In a beta decay, a neutron is converted into a proton, while an electron (beta particle) is emitted. This causes the atomic number of the nuclide to increase by 1 while the mass number remains unchanged. Thus, after the first beta decay, the isotope formed will be \(_{93}^{239} \mathrm{Np}\) (Neptunium).

Determine the final fissionable product formed after the second beta decay

: After the second beta decay, the atomic number of the isotope will again increase by 1 while the mass number remains unchanged. This results in the formation of the isotope \(_{94}^{239} \mathrm{Pu}\) (Plutonium) as the final fissionable product. So, the final fissionable product formed from the neutron capture and two successive beta decays of \(_{92}^{238} \mathrm{U}\) is \(_{94}^{239} \mathrm{Pu}\).

Key concepts

Neutron Capture

Neutron capture is a crucial process in nuclear reactions, especially within breeder reactors.This reaction involves a nucleus capturing a free neutron, resulting in an increase in its mass number by one.The atomic number, however, stays the same, since no new protons are added.
In breeder reactors, this process helps convert non-fissionable isotopes like \(_{92}^{238} \mathrm{U}\) into a more reactive form.By adding the neutron, the uranium becomes \(_{92}^{239} \mathrm{U}\), setting the stage for further transformations.Understanding neutron capture is key to comprehending how breeder reactors function.This ability to "harvest" neutrons and turn unusable isotopes into something productive is what makes breeder reactors distinctively important in the nuclear industry.

• Increases Mass Number: Neutron added, no protons are added.
• Precursor to Beta Decay: Sets the stage for subsequent transformations.
• Facilitates Conversion: Converts non-fissionable materials into fissionable ones.

Beta Decay

Beta decay is an essential nuclear decay process that involves the transformation of a neutron into a proton.During this transformation, a beta particle, which is essentially an electron, is emitted from the nucleus.This emission process results in an increase of the atomic number by one, while the mass number remains constant.
After the first beta decay of \(_{92}^{239} \mathrm{U}\), the non-fissionable uranium turns into \(_{93}^{239} \mathrm{Np}\), known as Neptunium.A subsequent beta decay then transforms this Neptunium into \(_{94}^{239} \mathrm{Pu}\), or Plutonium, which is fissionable.Beta decay is crucial for producing more reactive isotopes from non-fissionable ones, especially in breeder reactors.

• Converts Neutron to Proton: Increases atomic number by one.
• Emits Beta Particle: Results in an electron emission.
• Facilitates Isotope Transformation: Used in breeder reactors to obtain fissionable materials.

Fissionable Materials

Fissionable materials are substances capable of sustaining a nuclear fission reaction.They are crucial in both energy production and nuclear weaponry.In the context of breeder reactors, fissionable materials are the end product of nuclear transformations.
The initial non-fissionable \(_{92}^{238} \mathrm{U}\) is converted through neutron capture and two beta decays into \(_{94}^{239} \mathrm{Pu}\).Plutonium-239 is a well-known fissionable material that can sustain a chain reaction; hence, it's widely used in the nuclear industry.Producing fissionable materials from non-fissionable isotopes increases resource efficiency and expands the usable fuel for reactors.

• Fuel for Nuclear Reactors: Essential for energy production.
• End Product of Transformations: Utilized from transformations of less reactive isotopes.
• Sustains Chain Reactions: Capable of maintaining a nuclear reaction.