Analysis of Integral Experiments

Analysis of Mixed-Oxide Fueled Critical Ex periments Using ENDF/B-IV Data, H. S. Cheng (BNL) 

Accurate prediction of criticality is essential not only for the quality design of plutonium recycle cores tmt also for the safety of handling fdutonium assemblies. To assess the ffllL capability in this regard, multigroup cross sections based on the latest nuclear data file, ENDF/B-IV, were used in conjunction with the lattice analysis code, HAMMER, and the two-dimensional (2-D) mnltigroup discrete ordinate code, TW0TRAN, to analyze a series of mixed-oxide-fneled critical experiments. These critical experiments which covered a wide range of water-to-fiiel ratios and Pu compositions represent a set of excellent benchmarks for validation of both the analytical methods and nuclear data for criticality prediction of mixed-oxide fuel assemblies typical of pin tonium recycle cores in LWRs. 

The effect of using more energy groups (8 with S thermal groups) and higher Sn orders (S and SiJ in TW0TRAN tends to reduce keff toward unity, each by about 0.1 B 0.2%, which, although within the experimental uncertainty, does improve the accuracy in keff. 

SUICH and H. C. HONECK, The HAMMER System-Heterogeneous Analysis by Multigroup Methods of Etqxmentials and Reactors, OP-1064, Savannah River Lab. (1967). 

LATHROP and F. W. BRINKLEY, Theory and Use of the General-Geometry TW0TRAN Program, LA-4432, Los AUmos Scientific Lab. (1970). 

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