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Artigo IPEN-doc 27614 Main experiments performed at the IPEN/MB-01 RR using UO2 fuel rods core2020 - BITELLI, U.D.; COELHO, P.R.P.; FERREIRA, P.S.B.; ALVES, M.A.P.; SILVA, A.A.; SANTOS, A.; DINIZ, R.; JEREZ, R.; FUGA, R.; FANARO, L.C.C.B.; KURAMOTO, R.; ABE, A.; LAMBIASI, B.; GIADA, M.; FER, N.; MARTINS, F.; MURA, L.; SANTOS, D.F.; AREDES, V.; MAEDA, R.; GONNELI, E.; SILVA, A.F.P.; PURGATO, R.; GONÇALVES, L.B.; SILVA, G.S.A.; PINTO, L.; SOUZA, G.This paper aims to show the main experimental utilization of the IPEN/MB-01 zero power reactor during the last 30 years with 3663 operations cycles. The IPEN/MB-01 reactor it was mainly used to validation of calculation methodology used in nuclear reactor cores design.Artigo IPEN-doc 27559 APSD up to 100 kHz dataset measured in the IPEN/MB-01 research reactor facility2020 - SANTOS, DIOGO F. dos; SANTOS, ADIMIR dos; DINIZ, RICARDOThe data presented in this work are from the very accu- rate reactor noise measurements performed in the IPEN/MB- 01 research reactor facility. The quantity inferred from the measured data was the Auto Power Spectral Density (APSD) with the frequency range extended up to 100 kHz. The core configuration considered a short version of the IPEN/MB-01 core, consisted of a 26 ×24 rectangular array of fuel rods with control banks totally withdrawn. The measured reactiv- ity excess for this configuration was equal to (10 ±3) pcm. The subcriticality was reached by poisoning the reactor wa- ter with boric acid (H 3 BO 3 ) in the concentrations of 286.8 and 578.6 ppm of natural boron. The main goal of these experiments was to test subcritical configurations with uni- form poisoning. The average temperature for the experiment with 286.8 ppm of natural boron was (19.82 ±0.37) °C and that for the 578.6 ppm was (19.89 ±0.09) °C. The core was driven by the 241 Am-Be start-up source ( ∼1.0 Ci) of the facil- ity placed in the reflector. The APSD (in units of count 2 /Hz) was inferred employing the IPEN/MB-01 Correlator. The basic measured data arise from the pulses of two 3 He Centronic detectors placed in the reflector region.Relatório IPEN-doc 27473 Rotina experimental: previsão de massa crítica do núcleo do reator IPEN/MB-01 tipo placa2020 - DINIZ, RICARDOEste relatório apresenta um procedimento experimental para a previsão de massa crítica do núcleo do reator IPEN/MB-01 com elementos combustíveis tipo placa, utilizando a técnica do inverso da multiplicação subcrítica (1/M).Artigo IPEN-doc 27116 New delayed neutron group constants and covariances for LWR core applications, combining summation calculations and integral experiments2020 - LECONTE, P.; ARCHIER, P.; DE SAINT JEAN, C.; DINIZ, R.; SANTOS, ADIMIR dos; FAUTRAT, L.; FOLIGNO, D.; GESLOT, B.; GILAD, E.; TAMAGNO, P.; TRUCHET, G.; ZOIA, A.Artigo IPEN-doc 26513 The correlation matrix for the effective delayed neutron parameters of the IPEN/MB-01 reactor2020 - SANTOS, ADIMIR dos; DINIZ, RICARDOThe correlation matrix for the effective delayed neutron parameters of the IPEN/MB-01 reactor has been successfully built in this work. A standard procedure employed in several least-squares approaches was adopted to cope with this task. One of the most important applications of the effective delayed neutron parameters is to serve as input data for the relationship between reactivity and asymptotic period of a nuclear reactor given by the Inhour equation. Employing this equation, the reactivity was calculated for several periods both negative and positive. The reactivity error propagation was considered with and without the correlation matrix. The analyses of this procedure reveal that the consideration of the correlation matrix is very important. In general, the introduction of the correlation matrix reduces the overall uncertainty by a reasonable amount. There are huge cancellations in the uncertainty analyses. The analyses also reveal that the uncertainty in the reactivity will depend on the specific period range where this quantity is considered. Considering the correlation and for most of the period range considered, the reactivity uncertainties for negative periods are around 3.5% while for positive ones they are nearly 2%. If the correlation matrix is not considered the reactivity uncertainties are as high as 6%. All uncertainties considered in this work are 1-r values. There are two extreme cases where the correlation matrix plays no role; very large negative periods and very small positive periods. In the first case, the first decay constant plays a fundamental role while in the second the prompt neutron generation is of major importance. The experiments performed at the IPEN/MB-01 reactor and evaluated for inclusion in the IRPhE handbook for the determination of the effective delayed neutron parameters will be extremely benefited considering the inclusion of their correlation matrix. The final product can be considered extremely useful to validate methods and nuclear data related to the reactivity determination of thermal reactors fueled with Uranium.Relatório IPEN-doc 25042 Comissionamento2018 - DINIZ, RICARDOEste relatório de comissionamento apresenta um procedimento experimental para a previsão de massa crítica do núcleo do reator IPEN/MB-01 com elementos combustíveis tipo placa, utilizandoa técnica do inverso da multiplicação subcrítica (1/M).Relatório IPEN-doc 24895 Comissionamento: Previsão de massa crítica do núcleo do reator IPEN/MB-01 tipo placa2018 - DINIZ, RICARDOEste relatório de comissionamento apresenta um procedimento experimental para a previsão de massa crítica do núcleo do reator IPEN/MB-01 com elementos combustíveis tipo placa, utilizandoa técnica do inverso da multiplicação subcrítica (1/M).Artigo IPEN-doc 24689 Characterization of neutron detectors at the IPEN/MB-01 nuclear reactor2017 - GONNELLI, EDUARDO; PINTO, LETICIA N.; DINIZ, RICARDO; SANTOS, ADIMIR dosA huge Brazilian nuclear project, the Brazilian Multipurpose Research Reactor (RMB), is being carried out and one of the project steps is to verify experimentally the physical quantities related to the operational performance of the new fuel elements. In this context, the aim of this work is to characterize the neutron detectors due to its crucial role during the nuclear reactor criticalization. A series of experiments was performed at the IPEN/MB-01 nuclear reactor in order to characterize a set of new helium-3-filled gas proportional counters. The detectors characterization procedure takes into account the operating voltage curve and the detectors dead time. The Rossi-α method was employed in order to acquire the time difference between a detected neutron pair. The dead time determination through the Rossi-α method is very important to discriminate the reflector effect over the neutron lifetimes in subcritical reactivity levels. Furthermore, the Auto Power Spectral Densities (APSD) for those new detectors were experimentally acquired and those results were compared among some well-known detectors and with theoretical simulation results using the MCNP5 code with the ENDF/B-VII.0 library neutron data.Artigo IPEN-doc 22567 A simple way to overcome the shortage of sup(3)He detectors in the IPEN/MB-01 nuclear reactor2016 - GONNELLI, E.; PINTO, L.N.; LANDIM, H.R.; DINIZ, R.; JEREZ, R.; SANTOS, A. dosIn order to overcome the shortage of 3He detectors for subcritical experiments in the IPEN/MB-01 reactor, some experiments were performed employing less sensitive detectors, such as BF3, and a logic input module, which sums the counts from different detectors. Through microscopic and macroscopic neutron noise technique, it was possible to obtain, respectively, Rossi-α distribution and Auto Power Spectral Densities (APSD) for each detector configuration and various subcritical levels, and the prompt neutron decay constant (α) was extracted through a least squares procedure. In addition, Cross Power Spectral Densities (CPSD) were acquired for different types of detectors and the correlation among those detectors was confirmed. It was also observed that there was no loss of correlation among the neutron pulses, and therefore, the CPSD curves demonstrated the presence of correlated events. The α parameter was used as an indicator for the comparison of the results and for the quality of the experimental data. The obtained values demonstrate that the sum of counts technique does not present loss of information (correlated neutrons) even for different models and types of detectors, suggesting that the technique may be employed in neutron noise measurements for subcritical reactivity.Artigo IPEN-doc 22572 Neutron lifetimes behavior analysis considering the two-region kinetic model in the IPEN/MB-01 reactor2014 - GONNELLI, EDUARDO; DINIZ, RICARDO