What is the neutron spectrum?
Neutron flux spectrum represents the distribution of neutron energies within some medium. From the physics point of view, the main differences among reactor types arise from differences in their neutron energy spectra.
What is fission spectrum?
The energy distribution of these fission spectrum neutrons is often represented by the so-called Watt Distribution. Neutrons evaporating during fission. These fast neutrons have different energies but with a definite spectrum, an energy distribution.
How does a fast neutron reactor work?
Fast reactors are nuclear reactors that are designed to maintain their neutrons at high energies. Fast neutrons can unlock the energy in the dominant isotope of uranium (U238) and thus extend known fuel resources by many orders of magnitude, enabling nuclear power to achieve long term sustainability.
In what form is the energy from a fission reaction released?
kinetic energy
The energy of nuclear fission is released as kinetic energy of the fission products and fragments, and as electromagnetic radiation in the form of gamma rays; in a nuclear reactor, the energy is converted to heat as the particles and gamma rays collide with the atoms that make up the reactor and its working fluid.
How does a nuclear chain reaction occur?
A chain reaction refers to a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats. The process may be controlled (nuclear power) or uncontrolled (nuclear weapons).
Why thermal neutron is used in nuclear fission?
Relatively slow and of low energy, thermal neutrons exhibit properties, such as large cross sections in fission, that make them desirable in certain chain-reaction applications. Furthermore, the long de Broglie wavelengths of thermal neutrons make them valuable for certain applications of neutron optics.
What is fast neutron flux?
The neutron flux, φ, is a scalar quantity used in nuclear physics and nuclear reactor physics. It is the total length travelled by all free neutrons per unit time and volume.
What is the fission cross-section of uranium 235?
Uranium 235 is a fissile isotope, and its fission cross-section for thermal neutrons is about 585 barns (for 0.0253 eV neutron). For fast neutrons, its fission cross-section is on the order of barns. Most absorption reactions result in fission reaction, but a minority results in radiative capture forming 236 U.
Is uranium-235 a fissile isotope?
Uranium-235 (235U) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope with a primordial nuclide found in significant quantity in nature.
What is uranium-235 (235U)?
Jump to navigation Jump to search. Uranium-235 (235U) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope with a primordial nuclide found in significant quantity in nature.
What is the critical mass of a 235 uranium bomb?
The nominal spherical critical mass for an untampered 235 U nuclear weapon is 56 kilograms (123 lb), a sphere 17.32 cm (6.8″) in diameter. The material must be 85% or more of 235 U and is known as weapons grade uranium, though for a crude, inefficient weapon 20% is sufficient (called weapon (s)-usable ).