The Evaluation of the Effective Kinetic Parameters and Reactivity of the IPEN/MB-01 Reactor for the International Reactor Physics Experiment Evaluation Project

Author(s)

dos Santos, Adimir ^[1] ; Diniz, Ricardo ^[1]

Affiliation

^[1] Inst Pesquisas Energet & Nucl IPEN CNEN SP, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: NUCLEAR SCIENCE AND ENGINEERING; v. 178, n. 4, p. 459-478, DEC 2014.
• Web of Science Citations: 3

Abstract

The evaluation of the experiments of the effective delayed neutron parameters and reactivity performed in the IPENI MB-01 research reactor facility has been successfully accomplished. The evaluated data are of very good quality and fulfill the requirements of a benchmark. The recently released MCNP6 together with the ENDFIB-VII.1, JENDL-4.0, JEFF-3.1.1, ENDF/B-VII.0, and JENDL-3.3 nuclear data libraries has been employed to calculate the effective delayed neutron parameters adopting the benchmark model of the IPENI MB-01 reactor available in the International Handbook of Reactor Physics Benchmark Experiments. The analysis reveals that all these nuclear data libraries produced satisfactory results for beta(eff), beta(vertical bar Lambda)(eff) , and Lambda. The same cannot be said for determining the reactivity using the Inhour equation. It was shown that there is a clear tendency to increase the deviation with the absolute value of the reactivity for negative periods. Only JENDL-3.3 and JEFF-3.1.1 produced results that are inside the 3 sigma range of the benchmark value uncertainty. Specifically for the case of ENDF/B-VII.1, a good part of this discrepancy is due to the decay constant of the first group of delayed neutrons, which is overestimated according to the experimental value measured in the IPEN/MB-01 reactor. (AU)