Search results
Results from the WOW.Com Content Network
The sources are important for safe reactor startup. The spontaneous fission and ambient radiation such as cosmic rays serve as weak neutron sources, but these are too weak for the reactor instrumentation to detect; relying on them could lead to a "blind" start, which is a potentially unsafe condition. Blind startups were used in the early days ...
Some isotopes undergo spontaneous fission (SF) with emission of neutrons.The most common spontaneous fission source is the isotope californium-252. 252 Cf and all other SF neutron sources are made by irradiating uranium or a transuranic element in a nuclear reactor, where neutrons are absorbed in the starting material and its subsequent reaction products, transmuting the starting material into ...
A common type of startup neutron source is a mixture of an alpha particle emitter such as 241 Am (americium-241) with a lightweight isotope such as 9 Be (beryllium-9). The primary sources described above have to be used with fresh reactor cores. For operational reactors, secondary sources are used; most often a combination of antimony with ...
A modulated neutron initiator is a neutron source capable of producing a burst of neutrons on activation. It is a crucial part of some nuclear weapons, as its role is to "kick-start" the chain reaction at the optimal moment when the configuration is prompt critical. It is also known as an internal neutron initiator.
Neutron radiation is a form of ionizing radiation that presents as free neutrons.Typical phenomena are nuclear fission or nuclear fusion causing the release of free neutrons, which then react with nuclei of other atoms to form new nuclides—which, in turn, may trigger further neutron radiation.
Finally, the lack of nuclear data at high neutron energies limits the efficiency of the design. This latter issue can be overcome by introducing a neutron moderator between the neutron source and the fuel, but this can lead to increased leakage as the moderator will also scatter neutrons away from the fuel. Changing the geometry of the reactor ...
Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium , tritium , or a mixture of these two isotopes into a metal hydride target which also contains ...
Pages in category "Neutron sources" The following 27 pages are in this category, out of 27 total. This list may not reflect recent changes. ...