Analysis of benchmark critical experiments with ENDF/B-VI data sets
Several clean critical experiments were analyzed with ENDF/B-VI data to assess the adequacy of the data for U{sup 235}, U{sup 238} and oxygen. These experiments were (1) a set of homogeneous U{sup 235}-H{sub 2}O assemblies spanning a wide range of hydrogen/uranium ratio, and (2) TRX-1, a simple, H{sub 2}O-moderated Bettis lattice of slightly-enriched uranium metal rods. The analyses used the Monte Carlo program RCP01, with explicit three-dimensional geometry and detailed representation of cross sections. For the homogeneous criticals, calculated k{sub crit} values for large, thermal assemblies show good agreement with experiment. This supports the evaluated thermal criticality parameters for U{sup 235}. However, for assemblies with smaller H/U ratios, k{sub crit} values increase significantly with increasing leakage and flux-spectrum hardness. These trends suggest that leakage is underpredicted and that the resonance eta of the ENDF/B-VI U{sup 235} is too large. For TRX-1, reasonably good agreement is found with measured lattice parameters (reaction-rate ratios). Of primary interest is rho28, the ratio of above-thermal to thermal U{sup 238} capture. Calculated rho28 is 2.3 ({+-} 1.7) % above measurement, suggesting that U{sup 238} resonance capture remains slightly overpredicted with ENDF/B-VI. However, agreement is better than observed with earlier versions of ENDF/B.
- Research Organization:
- Bettis Atomic Power Lab., West Mifflin, PA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC11-93PN38195
- OSTI ID:
- 10108777
- Report Number(s):
- WAPD-T-2949; CONF-910414-43; ON: DE94004450; TRN: 94:001493
- Resource Relation:
- Conference: International topical meeting on advances in mathematics, computation and reactor physics,Pittsburgh, PA (United States),28 Apr - 2 May 1991; Other Information: PBD: [1991]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NUCLEAR DATA COLLECTIONS
EVALUATION
URANIUM 235
URANIUM 238
OXYGEN
REACTOR KINETICS
BENCHMARKS
EVALUATED DATA
FISSION SPECTRA
WATER
ZERO POWER REACTORS
ELASTIC SCATTERING
CAPTURE
CRITICALITY
R CODES
ENERGY SPECTRA
REACTOR LATTICE PARAMETERS
MODIFICATIONS
DATA ANALYSIS
NEUTRON REACTIONS
220100
THEORY AND CALCULATION