RENATO YOICHI RIBEIRO KURAMOTO

RENATO YOICHI RIBEIRO KURAMOTO

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Absolute measurement of betasub(eff) based on feynman-alfa experiments and the two-region model in the IPEN/MB-01 research reactor
2007 - KURAMOTO, RENATO Y.R.; SANTOS, ADIMIR; JEREZ, ROGERIO; DINIZ, RICARDO
Kinetic parameters determination through power sectral densities measurements using pulse-type detectors in the IPEN/MB-01 research reactor
2007 - KURAMOTO, RENATO Y.R.; SANTOS, ADIMIR dos; JEREZ, ROGERIO; DINIZ, RICARDO
Nowadays, a collaborative effort to improve the prediction accuracy of some kinetic parameters has been recommended. In special, a target accuracy of ±3% (1 s.d.) was requested for βeff calculations, in way that βeff values must be measured with an experimental error of less than 3%. In such a way, the Reactor Physics Group at IPEN/MB-01 Research Reactor has been compiled an experimental data bank of kinetic parameters, including βeff, Λ, βeff/Λ and others, based on noise analyses techniques. The implemented techniques are: Power Spectral Densities (PSD) using current-type detectors, Rossi-α and Feynman-α techniques. All these techniques provided βeff values with uncertainties within the target accuracy. In order to conclude this data bank, in this work we have been performed PSD measurements using pulse-type detectors. The main advantage of this technique is that it is possible to eliminate some electronic modules, needed in the current-mode experiments, which are sources of parasitic noises. Furthermore, this technique can explain an anomalous behavior reported in current-mode measurements, which is a non-observation of a theoretical predicted plateau above 200Hz, approximately. Once completed, the kinetic parameters data bank should provide valuable information to determine whether or not the currently data libraries are sufficiently accurate to predict these measured parameters. Further, we intend to submit a proposal for the first international benchmark related to βeff measurements, to the International Reactor Physics Experiment Evaluation Project (IRPhEP, NEA data bank).
Absolute measurements of beta sub(eff) based on Rossi-alfa experiments and the two-region model in the IPEN/MB-01 research reactor
2007 - KURAMOTO, RENATO Y.R.; SANTOS, ADIMIR dos; JEREZ, ROGERIO; DINIZ, RICARDO
Desenvolvimento de uma metodologia baseada no modelo de duas-regiões e em técnicas de análise de ruído microscópico para a medida absoluta dos parâmetros cinéticos Betasub(eff), Lambda e Betasub(eff/Lambda do reator IPEN/MB-01
2007 - KURAMOTO, RENATO Y.R.
Uma nova metodologia para a medida absoluta da fração efetiva de nêutrons atrasados βeff, baseada em técnicas de análise de ruído microscópico e no modelo de Duas- Regiões, foi desenvolvida no reator IPEN/MB-01. Diferentemente das demais técnicas, tais como o Método de Bennet Modificado, o Método do Número de Nelson e o Método da fonte de 252Cf, a principal vantagem da metodologia proposta é a obtenção de βeff de um modo puramente experimental, sem a necessidade de quaisquer outros parâmetros, sejam estes calculados ou provenientes de outros experimentos. Com a finalidade de validar este novo método, uma série de experimentos Rossi-α e Feynman-α foram realizados no reator IPEN/MB-01. De acordo com a metodologia proposta, βeff foi estimado com uma incerteza de 0.67%, a qual atende aos requisitos de precisão almejados. Além disso, o tempo de geração de nêutrons prontos , dentre outros parâmetros, também foi obtido experimentalmente via esta metodologia. Em geral, os parâmetros medidos estão em acordo com resultados provenientes de experimentos de análise de ruído macroscópico. Nas comparações teoria-experimento, os valores de βeff medidos neste trabalho mostram que a biblioteca JENDL3.3 apresenta a melhor performance (dentro de 1%). Esta concordância justifica a redução no yield de fissão do 235U proposta por Sakurai e Okajima.
Absolute measurement of βeff based on Feynman-α experiments and the two-region model in the IPEN/MB-01 research reactor
2007 - KURAMOTO, RENATO Y.R.; SANTOS, ADIMIR dos; JEREZ, ROGERIO; DINIZ, RICARDO
A new methodology for absolute measurement of the effective delayed neutron fraction βeff based on Feynman-α experiments and the two-region model was developed. This method made use of Feynman-α experiments and the two-region model. To examine the present methodology, a series of Feynman-α experiments were conducted at the IPEN/MB-01 research reactor facility. In contrast with other techniques like the slope method, Nelson-number method and 252Cf-source method, the main advantage of this new methodology is to obtain βeff with the required accuracy and without knowledge of any other parameter. By adopting the present approach, βeff was measured with a 0.67% uncertainty. In addition, the prompt neutron generation time, Λ, and other parameters, was also obtained in an absolute experimental way. In general, the measured parameters are in good agreement with the values found from frequency analysis experiments. The theory-experiment comparison for the βeff measured in this work shows that JENDL3.3 presented the best agreement (within 1%). The reduction of the 235U thermal yield as proposed by Okajima and Sakurai is completely justified according to the βeff measurements performed in this work.
Absolute measurement of βeff based on Rossi-α experiments and the two-region model in the IPEN/MB-01 research reactor
2008 - KURAMOTO, RENATO Y.R.; SANTOS, ADIMIR dos; JEREZ, ROGERIO; DINIZ, RICARDO
A new method for absolute measurement of the effective delayed neutron fraction βeff based on Rossi-α experiments and the two-region model was developed at the IPEN/MB-01 Research Reactor facility. In contrast with other techniques such as the slope method, the Nelson-number method, and the 252Cf-source method, the main advantage of this new methodology is to obtain the effective delayed neutron parameters in a purely experimental way, eliminating all parameters that are difficult to measure or calculate. In this way, Rossi-a experiments for validation of this method were performed at the IPEN/MB-01 facility, and with the use of the present approach, βeff was measured with a 1.46% uncertainty. In addition, the prompt neutron generation time A and other parameters were also obtained in an absolute experimental way. In general, the final results agree well with values from frequency analysis experiments. Comparison of theory and experiment reveals that JENDL-3.3 shows deviation for βeff lower than 1%, which meets the desired accuracy for the theoretical determination of this parameter. This work supports the reduction of the 235U thermal yield, as proposed by Okajima and Sakurai.