Resonance analysis and evaluation of the sup 235 U neutron induced cross sections

Technical Report · Fri Jun 01 00:00:00 EDT 1990

DOI:https://doi.org/10.2172/6804800· OSTI ID:6804800

Leal, L. C.

Neutron cross sections of fissile nuclei are of considerable interest for the understanding of parameters such as resonance absorption, resonance escape probability, resonance self-shielding,and the dependence of the reactivity on temperature. In the present study, new techniques for the evaluation of the {sup 235}U neutron cross sections are described. The Reich-Moore formalism of the Bayesian computer code SAMMY was used to perform consistent R-matrix multilevel analyses of the selected neutron cross-section data. The {Delta}{sub 3}-statistics of Dyson and Mehta, along with high-resolution data and the spin-separated fission cross-section data, have provided the possibility of developing a new methodology for the analysis and evaluation of neutron-nucleus cross sections. The results of the analysis consists of a set of resonance parameters which describe the {sup 235}U neutron cross sections up to 500 eV. The set of resonance parameters obtained through a R-matrix analysis are expected to satisfy statistical properties which lead to information on the nuclear structure. The resonance parameters were tested and showed good agreement with the theory. It is expected that the parametrization of the {sub 235}U neutron cross sections obtained in this dissertation represents the current state of art in data as well as in theory and, therefore, can be of direct use in reactor calculations. 44 refs., 21 figs., 8 tabs.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6804800
• Report Number(s): ORNL/TM-11547; ON: DE90011284; TRN: 90-020817
• Resource Relation: Other Information: Thesis (Ph.D.). Thesis submitted by L.C. Leal to Univ. of Tennessee, Knoxville
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
URANIUM 235 TARGET
NEUTRON REACTIONS
CROSS SECTIONS
DATA ANALYSIS
DOPPLER BROADENING
ENERGY DEPENDENCE
EV RANGE 100-1000
EXPERIMENTAL DATA
FINITE DIFFERENCE METHOD
R MATRIX
RESONANCE
THEORETICAL DATA
BARYON REACTIONS
DATA
ENERGY RANGE
EV RANGE
HADRON REACTIONS
INFORMATION
ITERATIVE METHODS
LINE BROADENING
MATRICES
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUMERICAL DATA
NUMERICAL SOLUTION
TARGETS
652020* - Nuclear Properties & Reactions
A=220 & above
Experimental