Temperature dependence of the Westcott g-factor for the actinide nuclides in ENDF/B-VI
Reactor neutron capture and fission reaction rates are determined as the product of the neutron flux density and the neutron capture or fission cross section. The standard energy for tabulation of thermal neutron cross sections is that of room temperature of 20.43{degree}C, corresponding to a neutron energy of 0.0253 eV or a neutron velocity of 2200 m/s. Since most reactors do not operate at a temperature of 20{degree}C, there must be some mechanism for converting the cross section, {sigma}{sub 0}, at the tabulated energy to the effective cross section {cflx {sigma}}, at the actual temperature of the reactor. Westcott developed a method for converting {sigma}{sub 0} to {cflx {sigma}} by describing the neutron spectrum as a combination of a Maxwellian distribution characterized by temperature, T, and an epithermal component, proportional to dE/E. For an isotope whose cross section does not vary inversely with the neutron velocity, {cflx {sigma}} = {sigma}{sub 0} (g + rs), where g is the Westcott g-factor, the epithermal index, r, is approximately the fraction of the total neutron density in the epithermal component, and s is a temperature dependent quantity related to the reduced resonance integral. The values for the g-factor at different temperature for actinide nuclides are given in this paper.
- Research Organization:
- Brookhaven National Lab., Upton, NY (USA)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 5520773
- Report Number(s):
- BNL-45256-R; CONF-9105218-1; ON: DE91014785; TRN: 91-018215
- Resource Relation:
- Conference: International conference on nuclear data for science and technology, Juelich (Germany, F.R.), 13-17 May 1991
- Country of Publication:
- United States
- Language:
- English
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Temperature dependence of the Westcott g-factor for neutron capture and neutron fission reactions in ENDF/B-VI
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Related Subjects
ACTINIDE ISOTOPES
NEUTRON REACTIONS
CROSS SECTIONS
TEMPERATURE DEPENDENCE
CAPTURE
FISSION
NUCLEAR DATA COLLECTIONS
THERMAL NEUTRONS
BARYON REACTIONS
BARYONS
ELEMENTARY PARTICLES
FERMIONS
HADRON REACTIONS
HADRONS
ISOTOPES
NEUTRONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
653003* - Nuclear Theory- Nuclear Reactions & Scattering