Evaluation for ENDF/B-IV of the neutron cross sections for /sup 235/U from 82 eV to 25 keV

Technical Report · Sat May 01 04:00:00 EDT 1976

DOI:https://doi.org/10.2172/7189870· OSTI ID:7189870

Peelle, R W

Capture and fission cross sections for /sup 235/U in the ''unresolved resonance'' energy region were evaluated to permit determination of local-average resonance parameters for the ENDF/B-IV cross section file. Microscopic data were examined for infinitely dilute average fission and capture cross sections and also for intermediate structure unlikely to be reproduced by statistical fluctuations of resonance widths and spacings within known laws. Evaluated cross sections, averaged over lethargy intervals greater than 0.1, were obtained as an average over selected data sets after appropriate renormalization. Estimated uncertainties are given for these evaluated average cross sections. The ''intermediate'' structure fluctuations common to a few independent data sets were approximated by straight lines joining successive cross sections at 120 selected energy points; the cross sections at the vertices were adjusted to reproduce the evaluated average cross sections over the broad energy regions. Data sources and methods are reviewed, output values are tabulated, and some modified procedures are suggested for future evaluations. Evaluated fission and capture integrals for the resolved resonance region are also tabulated. These are not in agreement with integrals based on the resonance parameters of ENDF/B versions III and IV. 8 tables, 5 figures.

• Research Organization: Oak Ridge National Lab., Tenn. (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7189870
• Report Number(s): ORNL-4955; ENDF-233
• Country of Publication: United States
• Language: English

Related Subjects

652025 -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Nuclear Reactions & Scattering-- (-1987)
652026* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Spontaneous & Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BARYON REACTIONS
CROSS SECTIONS
DATA ANALYSIS
ELECTROMAGNETIC RADIATION
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GAMMA RADIATION
HADRON REACTIONS
HEAVY NUCLEI
INTEGRALS
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MINUTES LIVING RADIOISOTOPES
NEUTRON REACTIONS
NUCLEAR REACTIONS
NUCLEI
NUCLEON REACTIONS
RADIATIONS
RADIOISOTOPES
RESONANCE INTEGRALS
TARGETS
URANIUM 235
URANIUM 235 TARGET
URANIUM 236
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES