PEDRO CARLOS RUSSO ROSSI

PEDRO CARLOS RUSSO ROSSI

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Feasibility to convert an advanced PWR from UO2 to a mixed (U,Th)O2 core
2017 - STEFANI, GIOVANNI L. de; MAIORINO, JOSE R.; MOREIRA, JOAO M. de L.; SANTOS, THIAGO A. dos; ROSSI, PEDRO C.R.
This work presents the neutronics and thermal hydraulics feasibility to convert the UO2 core of the Westinghouse AP1000 in a (U-Th)O2 core, rather than the traditional uranium dioxide, for the purpose of reducing long-lived actinides, especially plutonium, and generates a stock pile of 233U, which could in the future be used in advanced fuel cycles, in a more sustainable process and taking advantage of the large stock of thorium available on the planet and especially in Brazil. The reactor chosen as reference was the AP1000, which is considered to be one of the most reliable and modern reactor of the current Generation III, and its similarity to the reactors already consolidated and used in Brazil for electric power generation. The results show the feasibility and potentiality of the concept, without the necessity of changes in the core of the AP1000, and even with advantages over this. The neutron calculations were made by the SERPENT code. The results provided a maximum linear power density lower than the AP1000, favoring safety. In addition, the delayed neutron fraction and the reactivity coefficients proved to be adequate to ensure the safety of the concept. The results show that a production of about 260 Kg of 233U per cycle is possible, with a minimum production of fissile plutonium that favors the use of the concept in U-Th cycles.
The experimental determination of the 238U(n,gamma) and total fission reaction rates along the pellet radius of the IPEN/MB-01 reactor
2017 - MURA, LUIS F.L.; SANTOS, ADIMIR dos; DOMINGOS, DOUGLAS B.; ROSSI, PEDRO C.R.; JEREZ, ROGERIO
This work presents a new experimental approach to determine experimentally the reaction rate along the pellet radius of a research reactor facility. The methodology employs concentric hollow cylindrical lead collimators together with gamma-ray spectrometry in a special kind of HPGe detector for the discrimination of very low gamma energy emitted by Np-239 and Mo-99. The U-238 neutron capture and total fission rates were inferred, respectively, from the 106.2 keV gamma emitted by Np-239 and from the 140.51 keV gamma-ray emitted by Mo-99. These lower gamma-ray energies allow the thickness of the lead collimator to be small enough so that the correction factors applied to the procedure were minimized. This kind somewhat challenging experiment was successfully performed at the IPEN/MB-01 research reactor facility. The experiments are claimed to be well-defined, and they are suitable for a benchmark. The measured values of the total fission rates are mainly due to the thermal fissions in U-235 since in the IPEN/MB-01 reactor nearly 85% of the total fissions occur in the thermal neutron energy region. The theoretical analyses were performed using MCNP-5 together with the ENDF/B-VII.o library. The analyses reveal a very good agreement between the calculated and experimental results for the U-238 epithermal neutron capture reaction rates. However, the same can not be said for the thermal reaction rates which show discrepancies both in magnitude as well as in the shape of the attenuation of the reaction rates inside of the fuel pellet. The suspected reason for these discrepancies is the shape of the U-235 cross sections below 0.3 eV which might be different from that adopted in the ENDF/B-VII.o library. (C) 2016 Elsevier Ltd. All rights reserved.
Effects of fissioning nuclei distributions on fragment mass distributions for high energy fission
2012 - ANDRADE-II, E.; MENEZES, J.C.M.; DUARTE, S.B.; GARCIA, F.; ROSSI, P.C.R.; TAVARES, O.A.P.; DEPPMAN, A.
We study the effects of fissioning nuclei mass- and energy-distributions on the formation of fragments for fission induced by high energy probes. A Monte Carlo code called CRISP was used for obtaining mass distributions and spectra of the fissioning nuclei for reactions induced by 660 MeV protons on 241Am and on 239Np, by 500 MeV protons on 208Pb, and by Bremsstrahlung photons with end-point energies at 50 MeV and 3500 MeV on 238U. The results show that even at high excitation energies, asymmetric fission may still contribute significantly to the fission cross section of actinide nuclei, while it is the dominante mode in the case of lead. However, more precise data for high energy fission on actinide are necessary in order to allow definite conclusions.
Neutron star mass correlation with sound velocity and incompressibility at the star center in the polytropic approximation
2010 - FERRARI, L.; ROSSI, P.C.R.; MALHEIRO, M.
A polytropic approach to neutron stars
2010 - FERRARI, L.; ROSSI, P.C.R.; MALHEIRO, M.
Computational calculation of the neutron fluxes at the GCFTR-2 fusion-fission hybrid reactor
2014 - PINTO, L.N.; GONNELLI, E.; ROSSI, P.C.R.; SANTOS, A. dos
Neutronic analysis of a U-Mo-Al fuel and europium as burnable poison
2016 - MUNIZ, RAFAEL O.R.; SANTOS, ADIMIR dos; YAMAGUCHI, MITSUO; ROSSI, PEDRO C.R.; DOMINGOS, DOUGLAS B.; MURA, LUIS F.; TEIXEIRA e SILVA, ANTONIO
New core configurations for the IPEN/CNEN-SP IEAR-R1 Research Reactor using higher density fuels
2015 - JOAO, THIAGO G.; ROSSI, PEDRO C.R.; TEIXEIRA e SILVA, ANTONIO
Neutron damage in the plasma chamber first wall of the GCFTR-2 fusion-fission hybrid reactor
2014 - PINTO, L.N.; GONNELLI, E.; ROSSI, P.C.R.; CARLUCCIO, T.; SANTOS, A. dos
The successful development of energy-conversion machines based on either nuclear fission or fusion is completely dependent on the behaviour of the engineering materials used to construct the fuel containment and primary heat extraction systems. Such materials must be designed in order to maintain their structural integrity and dimensional stability in an environment involving high temperatures and heat fluxes, corrosive media, high stresses and intense neutron fluxes. However, despite the various others damage issues, such as the effects of plasma radiation and particle flux, the neutron flux is sufficiently energetic to displace atoms from their crystalline lattice sites. It is clear that the understanding of the neutron damage is essential for the development and safe operation of nuclear systems. Considering this context, the work presents a study of neutron damage in the Gas Cooled Fast Transmutation Reactor (GCFTR-2) driven by a Tokamak D-T fusion neutron source of 14.03 MeV. The theoretical analysis was performed by MCNP-5 and the ENDF/B-VII.1 neutron data library. A brief discussion about the determination of the radiation damage is presented, along with an analysis of the total neutron energy deposition in seven points through the material of the plasma source wall (PSW), in which was considered the HT-9 steel. The neutron flux was subdivided into three energy groups and their behaviour through the material was also examined.
Comparison between two gas-cooled tru burner subcritical reactors: fusion-fission and ADS
2011 - CARLUCCIO, T.; ROSSI, P.C.R.; ANGELO, G.; MAIORINO, J.R.; TALAMO, A.; GOHAR, Y.