How can fission reactions be controlled

When it is in operation, the central active core contains a huge number of neutrons traveling in every direction at very high speeds. The rate of fissions in the uranium nuclei in the MIT reactor is controlled chiefly by six control blades of boron-stainless steel which are inserted vertically alongside the fuel elements. Boron has the property of absorbing neutrons without re-emitting any.

When the control blades are fully inserted, they absorb so many neutrons from the uranium that there are not enough to allow a chain reaction to continue. To put the reactor into operation, the control blades are raised very slowly.

Water is pumped up through the reactor core and heated by fission. Pipes then feed the steam directly to a turbine to produce electricity. Nuclear reactors are the heart of a nuclear power plant. Nuclear Fission Creates Heat The main job of a reactor is to house and control nuclear fission —a process where atoms split and release energy.

Fission and Fusion: What is the Difference? There are two types of light-water reactors operating in America. Pressurized water reactors.

Graphic by Sarah Harman U. Department of Energy. The core water cycles back to the reactor to be reheated and the process is repeated. Most reactors are controlled by means of control rods that are made of a strongly neutron-absorbent material such as boron or cadmium. In addition to the need to capture neturons, the neutrons often have too much kinetic energy.

These fast neutrons are slowed through the use of a moderator such as heavy water and ordinary water. Some reactors use graphite as a moderator, but this design has several problems.