Accession Number:

ADA243065

Title:

Characterization of the Thermalness of a Fissile System with a 2-Group Diffusion Theory Parameter

Descriptive Note:

Final rept.,

Corporate Author:

NEW MEXICO UNIV ALBUQUERQUE DEPT OF CHEMICAL AND NUCLEAR ENGINEERING

Personal Author(s):

• Bredehoft, Brent B.

Report Date:

1991-12-01

Pagination or Media Count:

159.0

Abstract:

Tabulation of critical data has commonly been done using the hydrogen to fissile atom ratio HX. This does not account for the moderating contribution of other light nuclei in the system or for the absorption characteristics, important to the slowing down process. Using a two energy group diffusion theory analogy to the six-factor-formula, we define the parameter an appropriate parameter for defining moderation characteristics. This parameter adequately accounts for the important details of the slowing down process resonance absorption, total system scattering and moderation, and the effective use of thermal neutrons. This study evaluates several low to moderate enriched uranium systems with several types of moderators. It utilizes the TWODANT transport code with the Hansen Roach 16 group cross sections and group collapse theory to develop appropriate system models and 2 group cross sections.

Descriptors:

• *SCATTERING
• HYDROGEN
• CODING
• TRANSPORT
• THERMAL NEUTRONS
• URANIUM
• ENRICHMENT
• COLLAPSE
• RESONANCE ABSORPTION
• GROUPS(MATHEMATICS)
• MODELS
• ABSORPTION

Subject Categories:

• Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE