GREGORIO SOARES DE SOUZA

GREGORIO SOARES DE SOUZA

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New plate-type core of the IPEN/MB-01 research reactor facility for validation of RMB project
2020 - SANTOS, ADIMIR dos; YAMAGUCHI, MITSUO; FANARO, LEDA C.C.B.; SANTOS, DIOGO F. dos; SOUZA, GREGORIO S. de; JUNQUEIRA, FERNANDO de C.; SILVA, GRACIETE S. de A. e; BELCHIOR JUNIOR, ANTONIO; PRADO, ADELK de C.; JOAO, THIAGO G.; ROSSI, PEDRO C.R.
The IPEN/MB-01 research reactor had its first criticality in November 1988 and, ever since, has been of major importance in Brazilian reactor physics researches, achieving international level for experiments comparison and validation (benchmarks). In this facility it is possible to build many different core configurations (i.e., rectangular, square and cylindrical), once versatility and flexibility were both taken into account on its initial project. The core is a fissile material assembly, inserted in a water tank, where the chain reaction is self-maintained and controlled at low power levels, so that, in normal operation, the feedback effects of temperatures are negligible. The core is intended for neutrons simulation of light water moderated reactors allowing the experimental verification of the calculation methods, reactor cell and mesh structures, control rods effectiveness, isothermal reactivity coefficients and core dynamics due to reactivity insertions. The first standard IPEN/MB-01 core had UO2 rod-type fuel, 4.3 % enriched in U-235 and using B4C and Ag-In-Cd rods for safety and control of the reactor. The facility is located at IPEN/CNEN-SP (Nuclear and Energy Research Institute), in Sao Paulo - Brazil. Within the scope of the new research reactor project, the Brazilian Multipurpose Reactor (RMB), it was designed a new critical configuration for the IPEN/MB-01. After thirty years of work, the rod-type fuels were replaced by plate-type fuels, in order to validate the RMB calculation methodologies, as well as the nuclear data libraries used. The RMB is an open pool-type reactor with maximum power of 30 MW, being the core a 5x5 configuration, consisting of 23 fuel elements, made of U3Si2-Al, having a medium density of 3.7 gU/cm3 and 19.75% enriched in U-235, and two positions available in the core for materials irradiation devices. The production of radioisotopes, silicon doping, neutron activation analysis, nuclear fuels and structural materials testing and the development of scientific and technological research using neutron beams are the main targets of the RMB enterprise. The new IPEN/MB-01 core has a 4×5 configuration, having 19 fuel elements, consisting of U3Si2-Al, 2.8 gU/cm³ and 19.75% enriched in U-235, plus one aluminum block. The IPEN/MB-01 new plate-type fuel assembly uses Cadmium wires as burnable poison, as the one used in RMB core for controlling the core power density and excess of reactivity during its operation. The core is also reflected by 4 boxes of heavy water (D2O), inserted in a moderator tank of light water. The maximum nominal power is 100 W and, for a safe operation, the critical assembly has both safety and auxiliaries’ systems. This paper presents a description of the new core and the principal neutronic parameters. The new core of the IPEN/MB-01 will be certainly a world class benchmark core for the core physics calculation of research reactors.
Monte Carlo modeling of the new plate-type core for the Brazilian IPEN/MB-01 research reactor
2019 - JOÃO, THIAGO G.; SANTOS, DIOGO F. dos; ROSSI, PEDRO C.R.; SOUZA, GREGORIO S. de; SANTOS, ADIMIR dos
After 30 years of operation, the IPEN/MB-01 research reactor is about to receive a new plate-type core. This replacement is due to the Brazilian Multipurpose Reactor (RMB) needs, the largest project in nuclear engineering taking place in Brazil. The RMB will be a 30MW open pool-type research reactor, keeping the core in a 5x5 configuration (23 fuel elements, made of U3Si2-Al fuel plates, with 3.7 gU/cm3, 19.75% enriched in U-235 and two extra positions available for materials irradiation). The radioisotopes production, material irradiation, nuclear fuels structural testing and the development of scientific and technological research using neutron beams are the main targets of the RMB enterprise. In this way, in order to verify, experimentally, the calculation methods and data libraries used for the Brazilian Multipurpose Reactor design, reactor cell and mesh structures, control rods effectiveness, isothermal reactivity coefficients and core dynamics due to reactivity insertions, the IPEN/MB-01 new plate-type core is being implemented at the Nuclear and Energy Research Institute (IPEN/CNEN-SP), SP-Brazil. It´s a tank-type research reactor. The core has a 4×5 configuration, with 19 fuel elements (U3Si2-Al, 2.8gU/cm³ and 19.75% enriched in U-235), plus one aluminum block (internal irradiation position). As burnable poison, cadmium wires were used, once they are also employed at the RMB project to control the power density and the excess of reactivity during its operation. The core is reflected by four boxes of heavy water (D2O) and its maximum nominal power is 100W. Thereby, a Monte Carlo modeling was developed using the Monte Carlo N-Particle code (MCNP), along with NJOY, for processing the materials nuclear cross sections. This modeling for the IPEN/MB-01 new plate-type core is presented and some neutronic calculations were also depicted in this paper.
Subcritical boron experiments in the IPEN/MB-01 reactor
2019 - SANTOS, A. dos; SOUZA, G.S.; SANTOS, D.F.; ANDRADE, D.A.
Macroscopic (APSD and CPSD) and microscopic (Rossi-α) neutron noise experiments were performed in the IPEN/MB-01 reactor in order to measure subcritical reactivities. Subcritical states of up to around -6600 pcm were reached with insertion of boric acid (H3BO3) into the moderator tank. The subcritical kinetic model of Gandini and Salvatores was employed to infer the relative power between two consecutive subcritical cases, the subcritical reactivity (𝜌gen), and the subcriticality index (𝜁). This experimental methodology to measure these parameters was successfully employed in a previous experiment performed in the IPEN/MB-01 reactor. The measured subcritical reactivities are in good agreement for the APSD and Rossi-α cases. However, some drawbacks were found for the CPSD cases due to difficulties in the establishment of the cutoff frequency. The MCNP6.1 calculated subcritical reactivities were in a good agreement to APSD´s and Rossi-α measurement values. The ENDF/B-VII.0 nuclear data library was employed in all cases.
Antitumor potential induction and free radicals production in melanoma cells by boron neutron capture therapy
2011 - FLORES, F.F.; COELHO, P.R.P.; MUNIZ, R.O.R.; SOUZA, G.S.; ARRUDA NETO, J.; MARIA, DURVANEI A.
Utilização de filmes radiográficos para estudos dosimétricos em radioterapia com feixes de elétrons
2007 - SOUZA, GREGORIO S. de; SIQUEIRA, PAULO de T.D.
Metodologia para utilizacao de filmes radiograficos para avaliacao dosimetrica em radioterapia com feixes de eletrons
2008 - SOUZA, G.S.; SIQUEIRA, P.T.D.; FONSECA, G.P.; FURNARI, L.; YORIYAZ, H.; POLI, M.E.; RUBO, R.; ANTUNES, P.C.G.; RODRIGUES, L.N.
Study and implementation of the cadis methodology to research reactor shielding design
2013 - SOUZA, GREGORIO S.; SHORTO, JULIAN M.B.; SANTOS, ADIMIR dos
Improvements at the biological shielding of BNCT research facility in the IEA-R1 reactor
2009 - SOUZA, GREGORIO S.; MUNIZ, RAFAEL O.R.; COELHO, PAULO R.P.
Improvements in the biological shielding of the BNCT facility at the IEA-R1 reactor
2011 - SOUZA, GREGORIO S. de; COELHO, PAULO R.P.; SIQUEIRA, PAULO de T.D.
Estudo da adequacao do uso de detectores semicondutores para avaliacoes dosimetricas em radioterapia com feixe de eletrons
2007 - ANTUNES, P.C.G.; SIQUEIRA, P.T.D.; FURNARI, L.; YORIYAZ, H.; RUBO, R.; POLI, M.E.; RODRIGUES, L.N.; FONSECA, G.P.; SOUZA, G.S.