Criticality Safety Benchmark Experiment on 10% Enriched Uranyl Nitrate Solution Using a 28-cm-Thickness Slab Core

Abstract

The second series of critical experiments with 10% enriched uranyl nitrate solution using a 28-cm-thick slab core have been performed with the Static Experiment Critical Facility of the Japan Atomic Energy Research Institute. Systematic critical data were obtained by changing the uranium concentration of the fuel solution from 464 to 300 gU/l under various reflector conditions. In this paper, the thirteen critical configurations for water-reflected cores and un reflected cores are identified and evaluated. The effects of uncertainties in the experimental data on k ^eff are quantified by sensitivity studies. Benchmark model specifications that are necessary to construct a calculational model are given. The uncertainties of k _eff's included in the benchmark model specifications are approximately 0.1%δk _eff. The thirteen critical configurations are judged to be acceptable benchmark data. Using the benchmark model specifications, sample calculation results are provided with several sets of standard codes and cross section data.

KEYWORDS:

• criticality
• critical experiments
• benchmarks
• safety
• low-enriched uranium
• homogeneous
• bare
• water-reflected cores
• slabs
• moderated
• uranyl nitrates