JOSE ANTONIO BATISTA DE SOUZA

JOSE ANTONIO BATISTA DE SOUZA

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Distribuição de vazão entre os canais de resfriamento do elemento combustível do IEA-R1
2022 - TORRES, WALMIR M.; UMBEHAUN, PEDRO E.; ANDRADE, DELVONEI A.; SOUZA, JOSE A.B.
Um elemento de combustível “dummy” instrumentado (DMPV-01) com as mesmas características geométricas de um elemento de combustível MTR foi projetado e construído para experimentos de medição de distribuição de vazão no núcleo do reator IEA-R1. Esse elemento instrumentado também foi usado para medir a distribuição de vazão entre os canais retangulares formados pelas placas do elemento combustível. Duas sondas com tomadas de pressão foram construídas e montadas dentro dos canais de escoamento para medir a queda de pressão, enquanto a velocidade de escoamento foi calculada usando uma equação de queda de pressão para canais fechados. Este trabalho apresenta o procedimento experimental e os resultados da medição da distribuição de vazão entre os canais de escoamento. Os resultados mostram que a vazão nos canais periféricos é de 10% a 15% menor que a vazão média. É importante conhecer a vazão nos canais periféricos devido a incertezas nos valores da vazão no canal aberto formado entre dois elementos combustíveis adjacentes. Essas vazões são responsáveis pelo resfriamento de placas externas do elemento combustível.
Procedures for manufacturing an instrumented nuclear fuel element
2019 - DURAZZO, M.; UMBEHAUN, P.E.; TORRES, W.M.; SOUZA, J.A.B.; SILVA, D.G.; ANDRADE, D.A.
The IEA-R1 is an open pool research reactor that operated for many years at 2 MW. The reactor uses plate type fuel elements which are formed by assembling eighteen parallel fuel plates. During the years of reactor operation at 2 MW, thermohydraulic safety margins with respect to design limits were always very high. However, more intense oxidation on some external fuel plates was observed when the reactor power was increased to 5 MW. At this new power level, the safety margins are significantly reduced due to the increase of the heat flux on the plates. In order to measure, experimentally, the fuel plate temperature under operation, an instrumented fuel element was constructed to obtain temperature experimental data at various positions of one or more fuel plates in the fuel element. The manufacturing method is characterized by keeping the original fuel element design specifications. Type K stainless sheathed thermocouples are mounted into supports pads in unrestricted positions. During the fuel element assembling, the supports pads with the thermocouples are mechanically fixed by interference between two adjacent fuel plates. The thermocouple wires are directed through the space existing at the bottom of the mounting slot where the fuel plate is fixed to the side plates. The number of thermocouples installed is not restricted and depends only on adaptations that can be made on the mounting slots of the standard fuel element side plates. This work describes the manufacturing procedures for assembling such an instrumented fuel element.
Thermal hydraulic analysis improvement for the IEA-R1 research reactor and fuel assembly design modification
2018 - UMBEHAUN, PEDRO E.; TORRES, WALMIR M.; SOUZA, JOSE A.B.; YAMAGUCHI, MITSUO; SILVA, ANTONIO T. e; MESQUITA, ROBERTO N. de; SCURO, NIKOLAS L.; ANDRADE, DELVONEI A. de
This paper presents the sequence of activities to improve the thermal hydraulic analysis of the IEA-R1 research reactor to operate in safe conditions after power upgrade from 2 to 5 MW and core size reduction from 30 to 24 fuel assemblies. A realistic analysis needs the knowledge of the actual operation conditions (heat flow, flow rates) beyond the geometric data and the uncertainties associated with manufacturing and measures. A dummy fuel assembly was designed and constructed to measure the actual flow rate through the core fuel assemblies and its pressure drop. First results showed that the flow distribution over the core is nearly uniform. Nevertheless, the values are below than the calculated ones and the core bypass flow rate is greater than those estimated previously. Based on this, several activities were performed to identify and reduce the bypass flow, such as reduction of the flow rate through the sample irradiators, closing some unnecessary secondary holes on the matrix plate, improvement in the primary flow rate system and better fit of the core components on the matrix plate. A sub-aquatic visual system was used as an important tool to detect some bypass flow path. After these modifications, the fuel assemblies flow rate increased about 13%. Additional tests using the dummy fuel assembly were carried out to measure the internal flow distribution among the rectangular channels. The results showed that the flow rate through the outer channels is 10% - 15% lower than the internal ones. The flow rate in the channel formed between two adjacent fuel assemblies is an estimated parameter and it is difficult to measure because this is an open channel. A new thermal hydraulic analysis of the outermost plates of the fuel assemblies takes into account all this information. Then, a fuel design modification was proposed with the reduction of 50% in the uranium quantity in the outermost fuel plates. In order to avoid the oxidation of the outermost plates by high temperature, low flow rate, a reduction of 50% in the uranium density in the same ones was shown to be adequate to solve the problem.
A CFD numerical model for the flow distribution in a MTR fuel element
2017 - ANDRADE, D.A.; ANGELOA, G.; ANGELO, E.; SANTOS, P.H.G.; OLIVEIRA, F.B.V.; TORRES, W.M.; UMBEHAUN, P.E.; SOUZA, J.A.B.; BELCHIOR JUNIOR, A.; SABUNDJIAN, G.; PRADO, A.C.
Previously, an instrumented dummy fuel element (DMPV-01), with the same geometric characteristics of a MTR fuel element, was designed and constructed for pressure drop and flow distribution measurement experiments at the IEA-R1 reactor core. This dummy element was also used to measure the flow distribution among the rectangular flow channels formed by element fuel plates. A CFD numerical model was developed to complement the studies. This work presents the proposed CFD model as well as a comparison between numerical and experimental results of flow rate distribution among the internal flow channels. Numerical results show that the model reproduces the experiments very well and can be used for the studies as a more convenient and complementary tool.
A MTR fuel element flow distribution measurement preliminary results
2017 - TORRES, W.M.; UMBEHAUN, P.E.; ANDRADE, D.A.; SOUZA, J.A.B.
An instrumented dummy fuel element (DMPV-01) with the same geometric characteristics of a MTR fuel element was designed and constructed for flow distribution measurement experiments at the IEA-R1 reactor core. This dummy element was also used to measure the flow distribution among the rectangular flow channels formed by element fuel plates. Two probes with two pressure taps were constructed and assembled inside the flow channels to measure pressure drop and the flow velocity was calculated using pressure drop equation for closed channels. This work presents the experimental procedure and results of flow distribution measurement among the flow channels. Results show that the flow rate in the peripheral channels is 10 to 15% lower than the average flow rate. It is important to know the flow rate in peripheral channels because of uncertainties in values of flow rate in the open channel formed by two adjacent fuel elements. These flow rates are responsible by the cooling of external fuel plates.
A CFD numerical model for the flow distribution in a MTR fuel element
2015 - ANDRADE, DELVONEI A. de; ANGELO, GABRIEL; ANGELO, EDVALDO; SANTOS, PEDRO H. di G.; OLIVEIRA, FABIO B.V. de; TORRES, WALMIR M.; EMBEHAUN, PEDRO E.; SOUZA, JOSE A.B. de; BELCHIOR JUNIOR, ANTONIO; SABUNDJIAN, GAIANE; PRADO, ADELK de C.
Distribuicao de vazao no nucleo do reator de pesquisas IEA-R1
2001 - TORRES, W.M.; UMBEHAUN, P.E.; BAPTISTA FILHO, B.D.; ALMEIDA, J.C.; SOUZA, J.A.B.; SILVA, D.G.
Thermal-hydraulic design of a fuel mini-plate irradiator for the IEA-R1 research reactor
2003 - TORRES, W.M.; UMBEHAUN, P.E.; ANDRADE, D.A.; YAMAGUCHI, M.; SOUZA, J.A.B.
A MTR fuel element flow distribution measurement preliminary results
2003 - TORRES, W.M.; UMBEHAUN, P.E.; ANDRADE, D.A.; SOUZA, J.A.B.