Nuclear reaction

About: Nuclear reaction is a research topic. Over the lifetime, 21263 publications have been published within this topic receiving 352950 citations.

Theoretical Nuclear Physics

Abstract: A semi-empirical basis is used to describe and correlate the known nuclear properties including the theoretical concepts, methods, and considerations which have been devised in order to interpret the experimentsl material and to advance the ability to predict and control nuclear phenomena. General properties, two-body problems at low energies, nuclear forces, two-body problems at high energies, three- and four-body problems, nuclear spectroscopy, nuclear reactions, spontaneous decay of nuclei, interaction of nuclei with electromagnetic radiation, and beta decay are treated. 1200 references. (JFP)

Unified theory of nuclear reactions

Abstract: A new formulation of the theory of nuclear reactions based on the properties of a generalized “optical” potential is presented. The real and imaginary part of this potential satisfy a dispersion type relation while its poles give rise to resonances in nuclear reactions. A new derivation of the Breit-Wigner formula is given in which the concept of channel radius is not employed. This derivation is extended to the case of overlapping resonances. These results can then be employed to obtain the complex potential well model for pure elastic scattering. This potential well is shown to become real as the average width of the resonances increases. Reactions as well as elastic scattering are treated. Considering the former process in an isolated resonance, we obtain a nonresonant term analogous to the familiar potential scattering term of elastic scattering. This is just the direct interaction term which thus appears automatically in this formalism. Upon performing the appropriate energy averages over resonances, the complex potential well model is generalized so as to include inelastic scattering. The effects of the identity of nucleons is investigated. It is shown that our formalism is valid as long as the exit channels can at most contain one nucleon.

ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

Abstract: We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes, based on experimental data and theory predictions. The principal advances over the previous ENDF/B-VI library are the following: (1) New cross sections for U, Pu, Th, Np and Am actinide isotopes, with improved performance in integral validation criticality and neutron transmission benchmark tests; (2) More precise standard cross sections for neutron reactions on H, 6 Li, 10 B, Au and for 235,238 U fission, developed by a collaboration with the IAEA and the OECD/NEA Working Party on Evaluation Cooperation (WPEC); (3) Improved thermal neutron scattering; (4) An extensive set of neutron cross sections on fission products developed through a WPEC collaboration; (5) A large suite of photonuclear reactions; (6) Extension of many neutron- and proton-induced evaluations up to 150 MeV; (7) Many new light nucleus neutron and proton reactions; (8) Post-fission beta-delayed photon decay spectra; (9) New radioactive decay data; (10) New methods for uncertainties and covariances, together with covariance evaluations for some sample cases; and (11) New actinide fission energy deposition. The paper provides an overview of this library, consisting of 14 sublibraries in the same ENDF-6 format as the earlier ENDF/B-VI library. We describe each of the 14 sublibraries, focusing on neutron reactions. Extensive validation, using radiation transport codes to simulate measured critical assemblies, show major improvements: (a) The long-standing underprediction of low enriched uranium thermal assemblies is removed; (b) The 238 U and 208 Pb reflector biases in fast systems are largely removed; (c) ENDF/B-VI.8 good agreement for simulations of thermal high-enriched uranium assemblies is preserved; (d) The underprediction of fast criticality of 233,235 U and 239 Pu assemblies is removed; and (e) The intermediate spectrum critical assemblies are predicted more accurately. We anticipate that the new library will play an important role in nuclear technology applications, including transport simulations supporting national security, nonproliferation, advanced reactor and fuel cycle concepts, criticality safety, fusion, medicine, space applications, nuclear astrophysics, and nuclear physics facility design. The ENDF/B-VII.0 library is archived at the National Nuclear Data Center, BNL, and can be retrieved from www.nndc.bnl.gov .

Nuclear reactor analysis

Abstract: This comprehensive introduction covers the fundamental scientific principles governing nuclear fission reactors and the methods used in modern nuclear reactor analysis and design. The book is divided into four parts: Part 1 presents a relatively elementary and qualitative discussion of the basic concepts of nuclear fission chain reactions, including a brief review of relevant nuclear physics and a survey of modern power reactors. Part 2 develops a simple model of nuclear reactor behavior, assuming that the neutrons sustaining the fission chain reactions diffuse from point to point in the reactor in such a way that their energy and direction of motion can be ignored (one-speed diffusion theory). Part 3 generalizes this model to develop the primary tool of nuclear reactor analysis, multigroup diffusion theory. Part 4 illustrates the methods of nuclear reactor analysis by considering several important applications in reactor engineering, including a brief introduction to reactor core design. The text is written exclusively in S1 units and features numerous problems and exercises, many requiring digital computation.