How do control rods work in a nuclear fission reactor?

In Nuclear Fission, neutrons collide with radioactive atoms (eg Uranium-235) in order to split the atom into two smaller atoms and releasing energy. The more neutrons there are the faster the reaction so to slow it down you need to remove the neutrons.

This is done using control rods which absorb excess neutrons (reactions require 1 neutron and release 3 so there quickly becomes too many neutrons). They are composed of a material which has many stable isotopes (like Boron) so when the atoms absorb a neutron, they still don't become radioactive. If the reaction is going too fast, the control rods are lowered into the reactor, this increases their surace area to absorb neutrons. If the reaction is going too fast they are rasied up so less neutrons are absorbed.

JH
Answered by Jordan H. Physics tutor

7865 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Difference between compression ignition engine and a spark ignition engine


Two pendulums consist of a massless rigid rod of equal length attached to a small sphere of equal radius, with one sphere hollow for one pendulum and the other solid. Each pendulum undergoes damped SHM. Which pendulum has the largest time period?


A car is travelling at 10m/s when it brakes and decelerates at 2ms^-2 to a stop. How long does the car take to stop?


what would be the mass required to keep an object with a mass of 250kg orbiting at a constant distance of 100km with a linear velocity of 100m/s?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences