Lecture

Neutron Moderation with Absorption

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

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 covers the concepts of slowing down with absorption, treatment of resonances, resonance escape probability, temperature effect, and thermal and fast-reactor neutron spectra. The first part focuses on slowing down with absorption, particularly in hydrogen and infinite mass absorbers.

Instructors (3)

Andreas Pautz

Teaching & PhD PhD Students Sofia Portolan, Michel Saliba, Bishal Torrente, Alexis Paul Boris Claude Dupont-Bembinoff, Cynthia Camila Güttlein Past EPFL PhD Students Ting Zhu, Vladimir Vladimirov Brankov, Boris Aviv Hombourger, Damar Canggih Wicaksono, Petra Mala, Adolfo Rais, Valentyn Bykov, Daniel Jerôme Siefman, Evgeny Nikitin, Dionysios Chionis, Oskari Ville Pakari, Friederike Bostelmann, Jiani Gao, Efstathios Vlassopoulos, Alessandro Scolaro, Stefan Radman, Alexander Aures, Lubomír Bures, Ahmed Salah

Mathieu Hursin

Current work I'm currently heavily involved in the nuclear data community and with technical work towards the improvement of the latest version of the European library (JEFF). I'm leading an OECD/NEA subgroup in that direction. I'm also leading a Euratom project towards the production of multi-physics experimental data suitable for the validation of high-fidelity, high-resolution simulation tools. After a doctoral thesis on the high-fidelity modeling of control rod ejection in a pressurized water reactor at

Carlo Fiorina

Official source

Ontological neighbourhood

Energy engineering

Nuclear power: Topics in nuclear power

Related concepts (32)

Fast-neutron reactor

A fast-neutron reactor (FNR) or fast-spectrum reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons (carrying energies above 1 MeV or greater, on average), as opposed to slow thermal neutrons used in thermal-neutron reactors. Such a fast reactor needs no neutron moderator, but requires fuel that is relatively rich in fissile material when compared to that required for a thermal-neutron reactor.

Neutron moderator

In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, ideally without capturing any, leaving them as thermal neutrons with only minimal (thermal) kinetic energy. These thermal neutrons are immensely more susceptible than fast neutrons to propagate a nuclear chain reaction of uranium-235 or other fissile isotope by colliding with their atomic nucleus. Water (sometimes called "light water" in this context) is the most commonly used moderator (roughly 75% of the world's reactors).

Neutron temperature

The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term temperature is used, since hot, thermal and cold neutrons are moderated in a medium with a certain temperature. The neutron energy distribution is then adapted to the Maxwell distribution known for thermal motion. Qualitatively, the higher the temperature, the higher the kinetic energy of the free neutrons. The momentum and wavelength of the neutron are related through the de Broglie relation.

Discovery of the neutron

The discovery of the neutron and its properties was central to the extraordinary developments in atomic physics in the first half of the 20th century. Early in the century, Ernest Rutherford developed a crude model of the atom, based on the gold foil experiment of Hans Geiger and Ernest Marsden. In this model, atoms had their mass and positive electric charge concentrated in a very small nucleus.

Nuclear reactor physics

Nuclear reactor physics is the field of physics that studies and deals with the applied study and engineering applications of chain reaction to induce a controlled rate of fission in a nuclear reactor for the production of energy. Most nuclear reactors use a chain reaction to induce a controlled rate of nuclear fission in fissile material, releasing both energy and free neutrons.

Related lectures (64)

Neutron Transport Theory: Fundamentals and Applications

Explores neutron transport theory, scalar neutron flux, and Fick's law in reactor physics.

Modified One Group Theory: Media Containing Fuel

Explores the modified one group theory for thermal reactors, focusing on media containing fuel and resonance treatment.

Neutron Moderation with Absorption

Covers neutron moderation with absorption, including treatment of resonances, temperature effect, and neutron spectra.

Multigroup theory: Two-group method and group structures

Explains the two-group method, group structures, and multi-group constants.

Interactions of Neutrons with Matter