NULIF: neutron spectrum generator, few-group constant calculator, and fuel depletion code

Technical Report · Tue Jun 01 04:00:00 EDT 1976

OSTI ID:7357602

Wittkopf, W A; Tilford, J M; Andrews, II, J B; Kirschner, G; Hassan, N M; Colpo, P N

The NULIF code generates a microgroup neutron spectrum and calculates spectrum-weighted few-group parameters for use in a spatial diffusion code. A wide variety of fuel cells, non-fuel cells, and fuel lattices typical of PWR (or BWR) lattices are treated. A fuel depletion routine and change card capability allow a broad range of problems to be studied. Coefficient variation with fuel burnup, fuel temperature change, moderator temperature change, soluble boron concentration change, burnable poison variation, and control rod insertion are readily obtained. Heterogeneous effects, including resonance shielding and thermal flux depressions, are treated. Coefficients are obtained for one thermal group and up to three epithermal groups. A special output routine writes the few-group coefficient data in specified format on an output tape for automated fitting in the PDQ07-HARMONY system of spatial diffusion-depletion codes.

• Research Organization: Babcock and Wilcox Co., Lynchburg, Va. (USA). Nuclear Power Generation Div.
• OSTI ID: 7357602
• Report Number(s): BAW-10115
• Country of Publication: United States
• Language: English

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