Nuclear Data for Reactor Design

Benchmark Tests and Comparisons Using ENDF/B Version-Ill Data, JB. A, Zolotar, . M, Bohn, K. D. Dance (ANL) 

Benchmark testing of critical eiqieriments often employs simplified calculations for reasons of economy and convenience. The usefulness of the results are then dependent on previously calculated corrections or on the assumption that the parameters being calculated are insensitive to the approximations being used. The purpose of this work is to provide detailed benchmark calculations for testing ENDF/B Version-111 data as well as to examine the adequacy of the simplified calculational methods. 

Calculated and Measured Integral Results for Three Benchmark Critical Assemblies 

Hie principal results of this study are given in Table 1. Especially evident in these results is the improvement over previous ENDF/B versicms of the and central in-cell reaction rate ratios. The ceidral worth discrepancy is still present, however, although the agreement with experiment shows a slight inqirovement. Table 1 also provides new lh/% Ak/k conversicm factors for the assemblies vdiich are necessary for central worth comparisons. These values are based cm the Keepin delayed-neutron data and shoidd be taken to sq iersede previously quoted values. 

R should also be pointed out that this work is the initial utilization of die new SDX code for benchmark testing. The aUlity of the code to treat heterogeneity if desired and its economy of use have proved it to be a useful calculational tool for such a study. 

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