Abstracts and Available Papers Presented at the
2002 International RERTR Meeting

COMPARISONS OF DIFFUSION THEORY AND MONTE CARLO BURNUP

N. A. Hanan, R. B. Pond, M. M. Bretscher, and J. E. Matos

RERTR Program
Technology Development Division
Argonne National Laboratory
Argonne, Illinois 60439-4841 USA

ABSTRACT

Burnup analyses for research reactors have mostly been performed using diffusion theory codes.  Lately, with the increase in computing power, the Monte Carlo method is being used more frequently.  The Monte Carlo method provides a more precise way to perform burnup analyses for nuclear reactors.  However, the method is very computer and time intensive.  The purpose of this paper is to show that burnup analyses using diffusion theory with appropriate cross sections can provide results for different reactors, fuel enrichments, and fuel assembly types that are essentially the same as the Monte Carlo results.

This paper compares the results of diffusion theory and Monte Carlo burnup analyses for four different reactors (HFR-Petten in the Netherlands, WWR-SM in Uzbekistan, WWR-M in Ukraine, and TRR-II in Taiwan); different types of fuel assemblies (MTR, IRT-3M, IRT-MR, WWR-M2, and WWR-MR) were studied for these reactors. The performance parameters selected for these comparisons were: a) K-effective during the cycle; b) power produced in the fuel assemblies; and c) burnup-dependent isotopic compositions of the different fuel assemblies (²³⁵U, ²³⁸U, ¹³⁵Xe, and ²³⁹Pu).  The results show that for all parameters considered both the diffusion theory and the Monte Carlo burnup yield essentially identical results.

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