Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Neutron chain-reacting systems

In course

PHYS-443: Physics of nuclear reactors

In this course, one acquires an understanding of the basic neutronics interactions occurring in a nuclear fission reactor as well as the conditions for establishing and controlling a nuclear chain reaction. ...

Description

This lecture delves into the fission process in a nuclear reactor, focusing on practical fission fuels, fuel fission and capture cross sections, chain reaction, multiplication factor, 4 and 6 factor formulae, and the conversion (breeding) ratio.

Instructors (3)

Carlo Fiorina

Andreas Pautz

Mathieu Hursin

Official source

Ontological neighbourhood

Energy engineering

Nuclear power: Topics in nuclear power

Related concepts (32)

Breeder reactor

A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. These reactors can be fuelled with more commonly available isotopes of uranium and thorium, such as uranium-238 or thorium-232, as opposed to the rare uranium-235 which is used in conventional reactors. These materials are called fertile materials since they can be bred into fuel by these breeder reactors. Breeder reactors achieve this because their neutron economy is high enough to create more fissile fuel than they use.

Nuclear fusion–fission hybrid

Hybrid nuclear fusion–fission (hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes. The basic idea is to use high-energy fast neutrons from a fusion reactor to trigger fission in non-fissile fuels like U-238 or Th-232. Each neutron can trigger several fission events, multiplying the energy released by each fusion reaction hundreds of times. As the fission fuel is not fissile, there is no self-sustaining chain reaction from fission.

Nuclear fission product

Nuclear fission products are the atomic fragments left after a large atomic nucleus undergoes nuclear fission. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons, the release of heat energy (kinetic energy of the nuclei), and gamma rays. The two smaller nuclei are the fission products. (See also Fission products (by element)). About 0.2% to 0.4% of fissions are ternary fissions, producing a third light nucleus such as helium-4 (90%) or tritium (7%).

Nuclear reactor

A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid (water or gas), which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating.

Nuclear fuel

Nuclear fuel is material used in nuclear power stations to produce heat to power turbines. Heat is created when nuclear fuel undergoes nuclear fission. Most nuclear fuels contain heavy fissile actinide elements that are capable of undergoing and sustaining nuclear fission. The three most relevant fissile isotopes are uranium-233, uranium-235 and plutonium-239. When the unstable nuclei of these atoms are hit by a slow-moving neutron, they frequently split, creating two daughter nuclei and two or three more neutrons.

Related lectures (32)

Nuclear Fission: Total Cross Section Analysis

Analyzes the total cross section data for nuclear fission, covering energy dependence, transport, reactions, uncertainties, fission fragments, and radiological hazards.

Physics of Nuclear Reactors: Fundamentals and Advanced Concepts

Explores the fundamentals and challenges of nuclear reactors, covering neutron diffusion, fission, breeding, transmutation, and advanced technologies.

Neutron chain-reacting systems

Explores chain reactions, multiplication factor, fuel cycles, reactor design, and types of nuclear reactors, ending with a summary of key concepts.

Reactor Technology: Reactivity Variations and Control

Explores reactivity variations in reactor technology, covering short-term, medium-term, and long-term effects, means of control, and consequences.

Nuclear Fission: Energy Release and Neutron Interactions