Practical formalisms for nuclear data representation in evaluated nuclear data files in the unresolved resonance energy region

Journal Article · Wed Mar 01 04:00:00 EST 1978 · Nucl. Sci. Eng.; (United States)

OSTI ID:5134143

Gur, Y; Yiftah, S

The currently used formalism for neutron cross-section representation in the unresolved resonance energy range is based on the statistical parameters of the population of Breit--Wigner resonances. The present work introduces practical formalisms, based on parametric representation of the shielding factor curves, by which the values of effective cross sections can be obtained simply and quickly in the unresolved range, and suggests their use for neutron data representation. These formalisms were found to be compatible with such existing codes as MC/sup 2/, ETOX, HAMMER, ENDRUN, and MIGROS, and with such existing nuclear data files as ENDF/B and KEDAK. Each formalism is based on one interpolation scheme in temperature and one in sigma/sub 0/. The accuracy of four schemes in temperature and three schemes in sigma/sub 0/ was checked. Of these, three temperature schemes and one sigma/sub 0/ scheme were found to have better than 1% accuracy in the entire unresolved region; a formalism with better than 2% accuracy for representation was thus obtained. Observed spatially dependent self-shielding factors are transformed into pseudo-background cross-section-dependent (Bondarenko-type) self-shielding factors. Numerical values of the transformation for /sup 235/U and /sup 239/Pu self-shielding factors are given. It is shown that the formalisms can be used for the preprocessing of current nuclear data files in the unresolved range. 1 figure, 1 table.

• Research Organization: Israel Atomic Energy Commission, Yavne
• OSTI ID: 5134143
• Journal Information: Nucl. Sci. Eng.; (United States), Journal Name: Nucl. Sci. Eng.; (United States) Vol. 65:3; ISSN NSENA
• Country of Publication: United States
• Language: English

Related Subjects

652026* -- Nuclear Properties & Reactions
A=220 & above
Experimental-- Spontaneous & Induced Fission-- (-1987)
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACCURACY
BARYON REACTIONS
BARYONS
CROSS SECTIONS
DATA COMPILATION
ELEMENTARY PARTICLES
FERMIONS
HADRON REACTIONS
HADRONS
INTERMEDIATE NEUTRONS
INTERPOLATION
NEUTRON REACTIONS
NEUTRONS
NUCLEAR DATA COLLECTIONS
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
NUMERICAL SOLUTION
PLUTONIUM 239 TARGET
RECOMMENDATIONS
SELF-SHIELDING
TARGETS
URANIUM 235 TARGET