Critical Experiments on 10% Enriched Uranyl Nitrate Solution Using A 60-cm-Diameter Cylindrical Core

Abstract

A series of critical experiments with 10% enriched uranyl nitrate solution using a cylindrical core tank 60 cm in diameter have been performed with the Static Experiment Critical Facility at the Nuclear Fuel Cycle Safety Engineering Research Facility in the Tokai research establishment of the Japan Atomic Energy Research Institute. In the first series of experiments using the cylindrical core tank, systematic data of the critical height for water-reflected cores and unreflected cores were obtained by changing the uranium concentration of the fuel solution from 313 to 225 g U/ℓ. As the reactivity of each core is controlled only by solution height, these criticality configurations, which have simple cylindrical shapes, are available for the validation of calculation codes used in criticality safety designs of nuclear fuel cycle facilities.The neutron multiplication factors of experimental cores were calculated with the two-dimensional transport code TWOTRAN in the SRAC code system and with the continuous-energy Monte Carlo code MCNP4A, employing the Japanese evaluated nuclear data library JENDL-3.2. The calculations from the combination of these calculation codes and the nuclear data library reproduce the neutron multiplication factors within an error of 0.9% for the experimental configuration of critical cores.