Lecture

Diffusion of Neutrons - Part II

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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 review of the diffusion equation, analytical solutions for simple cases, and the physical significance of the diffusion area. It also discusses distributed sources in homogeneous media and boundary conditions related to neutron flux.

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

Related concepts (32)

Neutron capture

Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, which are repelled electrostatically. Neutron capture plays a significant role in the cosmic nucleosynthesis of heavy elements. In stars it can proceed in two ways: as a rapid process (r-process) or a slow process (s-process). Nuclei of masses greater than 56 cannot be formed by thermonuclear reactions (i.

Neutron poison

In applications such as nuclear reactors, a neutron poison (also called a neutron absorber or a nuclear poison) is a substance with a large neutron absorption cross-section. In such applications, absorbing neutrons is normally an undesirable effect. However, neutron-absorbing materials, also called poisons, are intentionally inserted into some types of reactors in order to lower the high reactivity of their initial fresh fuel load. Some of these poisons deplete as they absorb neutrons during reactor operation, while others remain relatively constant.

Neutron cross section

In nuclear physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. The neutron cross section σ can be defined as the area in cm2 for which the number of neutron-nuclei reactions taking place is equal to the product of the number of incident neutrons that would pass through the area and the number of target nuclei. In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power of a nuclear power plant.

Robin boundary condition

In mathematics, the Robin boundary condition (ˈrɒbɪn; properly ʁɔbɛ̃), or third type boundary condition, is a type of boundary condition, named after Victor Gustave Robin (1855–1897). When imposed on an ordinary or a partial differential equation, it is a specification of a linear combination of the values of a function and the values of its derivative on the boundary of the domain. Other equivalent names in use are Fourier-type condition and radiation condition.

Dirichlet boundary condition

In the mathematical study of differential equations, the Dirichlet (or first-type) boundary condition is a type of boundary condition, named after Peter Gustav Lejeune Dirichlet (1805–1859). When imposed on an ordinary or a partial differential equation, it specifies the values that a solution needs to take along the boundary of the domain. In finite element method (FEM) analysis, essential or Dirichlet boundary condition is defined by weighted-integral form of a differential equation.

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Diffusion of Neutrons

Covers the solutions of neutron diffusion, including analytical solutions, Laplacian in different geometries, and the physical significance of the diffusion area.

Neutron Transport Theory: Fundamentals and Applications

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

Multigroup theory

Covers the multigroup theory, focusing on the two-group method and resonance escape probability.