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

Analysis of dynamic reactivity by Monte Carlo methods: The impact of nuclear data

“…The two related integral quantities are β eff , i.e., the amount of delayed neutron emission, and τ = i a i /λ i , i.e., the average lifetime of delayed neutron emission. Analogous observations are reported 105 for instance for the IPEN/MB-01 benchmark (dos Santos and Diniz, 2014).…”

“…Intensive research efforts are being made so as to produce benchmark-quality experimental results for the kinetics parameters of light water reactors, such as in the case of the IPEN/MB-01 reactor (dos Santos and Diniz, 2014), including partial kinetics parameters and their associated uncertainties. Progress is however hindered by the complexity of the experimental techniques for singling out the family contributions (dos Santos and Diniz, 2014).…”

“…In parallel to comparison with direct experimental measurements of β eff,i and λ i (typically by reactor noise techniques), the validation of Monte Carlo calculations of the partial kinetics parameters by the IFP method can be carried out by resorting to the indirect approach proposed for instance for the CRO-CUS (OECD/NEA, 2007;Paratte et al, 2006) or IPEN/MB-01 (dos Santos and Diniz, 2014) benchmarks. The partial kinetics parameters β eff,i and λ i can be used in combination with β eff and Λ eff so as to infer the so-called dynamic reactivity ρ d of the core by the in-hour equation (Keepin, 1965).…”

“…In this paper, we extend the analysis that we have previously carried out for the CROCUS benchmark by considering a few benchmark-quality reactor configurations where the reactivity 110 ρ e (T ) has been accurately determined, namely the IPEN/MB-01 facility (dos Santos and Diniz, 2014), the SPERT III Ecore (Heffner and Wilson, 1961), and the SPERT IV D-12/25 core (Crocker and Stephan, 1964). In doing so, we pursue two intimately related goals: on one hand, we resort to the exper-115 imental in-hour curve in order to validate the new Tripoli-4 R routines enabling the calculation of partial kinetics parameters by the IFP method; on the other hand, investigation of the discrepancies between measured and computed reactivity allow assessing the impact of nuclear data on these calculations, and 120 possibly pointing out inconsistencies in the values of the decay constants and/or of the average delayed neutron number.…”

“…We will first address the case of the IPEN/MB-01 core, for which an analogous analysis has been recently carried out based on the MCNP Monte Carlo code (dos Santos and Diniz, 2014). Comparison with published results will allow establishing the proposed procedure on firm grounds.…”