Chapter 13: Problem 62
Graphite is used in nuclcar reactors (1) as a lubricant (2) as a fucl (3) for lining inside walls of the reactors as an insulator (4) for decreasing the velocity of ncutrons
Short Answer
Expert verified
Option 4 is correct: Graphite is used for decreasing the velocity of neutrons.
Step by step solution
01
Identify the function of graphite in nuclear reactors
Analyze the given options to determine the correct function of graphite in a nuclear reactor setup.
02
Evaluate each option
Assess each of the four provided options to see which one accurately describes the role of graphite in nuclear reactors:
03
Examine Option 1
Graphite is not typically used as a lubricant in nuclear reactors, making option 1 unlikely.
04
Examine Option 2
Graphite is not used as a fuel in nuclear reactors; instead, materials like uranium are used as fuel. Hence, option 2 is incorrect.
05
Examine Option 3
Graphite is also not used for lining inside walls as an insulator. This eliminates option 3.
06
Examine Option 4
Graphite is actually used as a moderator to decrease the velocity of neutrons in nuclear reactors. This makes option 4 the correct answer.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with Vaia!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Graphite as a Moderator
In nuclear reactors, graphite serves an essential function as a moderator. Moderators are crucial in nuclear reactors because they help sustain the nuclear chain reaction. One of graphite's primary roles is to slow down fast-moving neutrons. Fast neutrons are produced during nuclear fission, and if these neutrons remain too fast, they are less likely to cause subsequent fissions.
Graphite achieves this by scattering the neutrons through numerous collisions. With each collision, the neutron loses energy and slows down. This process increases the likelihood of the neutron causing additional fission events when it collides with fuel atoms like uranium-235. So, by using graphite as a moderator, reactors can maintain a controlled and steady chain reaction.
Other materials, such as heavy water, can also serve as moderators. However, graphite remains one of the most common choices due to its effective neutron slowing properties and relatively low cost.
Graphite achieves this by scattering the neutrons through numerous collisions. With each collision, the neutron loses energy and slows down. This process increases the likelihood of the neutron causing additional fission events when it collides with fuel atoms like uranium-235. So, by using graphite as a moderator, reactors can maintain a controlled and steady chain reaction.
Other materials, such as heavy water, can also serve as moderators. However, graphite remains one of the most common choices due to its effective neutron slowing properties and relatively low cost.
Nuclear Reactor Components
Nuclear reactors are complex systems made up of several critical components, all of which work together to harness nuclear energy safely and efficiently. Here's an overview of the main components:
- Fuel: Typically enriched uranium or plutonium, the fuel undergoes fission to produce energy.
- Moderator: Materials like graphite or heavy water slow down fast neutrons, making them more likely to cause fission.
- Control Rods: Made of neutron-absorbing materials like cadmium or boron, these rods are inserted or removed to control the rate of the fission reaction.
- Coolant: Substances like water, carbon dioxide, or liquid metals that transfer heat away from the reactor core, preventing overheating.
- Pressure Vessel: Contains the reactor core and the moderator, designed to withstand high pressures.
- Containment Structure: A robust barrier to prevent the release of radioactive materials in case of an accident.
Neutron Velocity Reduction
In nuclear reactors, reducing the velocity of neutrons is crucial for sustaining a nuclear chain reaction. Neutron velocity reduction, also known as thermalization, involves slowing down fast-moving neutrons produced during fission. Here’s how this process benefits the reactor:
By reducing neutron velocity, moderators like graphite enable reactors to operate smoothly and safely, maximizing energy output from the nuclear fuel.
- Increased Likelihood of Fission: Slower, 'thermal' neutrons are more likely to be captured by fuel nuclei like uranium-235, inducing further fission reactions.
- Chain Reaction Control: By moderating neutron speed, reactors can maintain a steady rate of fission, avoiding runaway reactions or shutdowns.
- Efficiency: Thermal neutrons are highly efficient at causing fission, meaning more energy can be extracted from the fuel.
By reducing neutron velocity, moderators like graphite enable reactors to operate smoothly and safely, maximizing energy output from the nuclear fuel.