Abstract: Every nuclear power reactor, whether of fusion or fission, is essentially a thermal system that generates electricity. In this sense, there are several problems in relation to this heat transport. The model of plasma confinement by magnetic force, in the nuclear fusion (sterellator and tokamak), has only been 20 years and recently some success in the quality of the generated plasma has been achieved. However, due to the large amount of energy coming from the plasma, the choice of the material that will carry the generated energy is quite troublesome, due to the need to handle a very high temperature for the nuclear fission standards. Solutions are explored by the scientific community to transport the energy generated in the case of the primary circuit, after exceeding breakeven temperature and models that are based on the fission reactors of the fourth generation and those currently in operation, to search for solutions regarding the transport of heat generated for the generation of electric energy. Several materials such as pressurized water, sodium, helium and boron have been considered and studied to form the primary heat transfer circuit for the exchanger. A thorough analysis of these materials is necessary. This research looked at some of these materials for heat transport and power generation. Lithium and helium were found to be the probable materials for conveying heat and cooling in the blanket. The results show that research on blanket materials needs more attention. The quality of these materials needs to be improved by material research, with the ODS EUROFER alloy and other research to reduce material erosion by helium nano bubbles. Plasma quality needs to be improved to keep constant and free of impurities when using lithium in liquid form.

Palavras-Chave: nuclear power; reactors; thermonuclear reactions; tokamak devices; renewable energy sources; iter tokamak; heating; heat transfer

BELLONI, MARCIO; CONTI, THADEU das N. Analysis of materials for heat transport in tokamaks. World Journal of Nuclear Science and Technology, v. 10, n. 1, p. 39-46, 2020. DOI: 10.4236/wjnst.2020.101005. Disponível em: http://repositorio.ipen.br/handle/123456789/31077. Acesso em: $DATA.

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Abstract: Correlations for the extension of a water vapor jet injected in a liquid pool were historically proposed considering the mass flux (kg/m2/s) as a constant. The results were satisfactory, however adjusting the values by linear regression. Although, it presents the following drawbacks: 1) the formulation is only valid for the specific range of data for what it was created; 2) it does not allow the analytical evaluation of the heat transfer coefficient from the extension equation. This paper proposes a new formulation for the calculation of the mass flux, in such a way to remove both of these drawbacks.

Palavras-Chave: water vapor; vapor jet ejectors; steam jet ejectors; reynolds number; heat transfer; vapor condensation; boiling

PACHECO, R.R.; FREIRE, L.O.; ROCHA, M.S.; SCURO, N.L.; MENEZES, M.O.; ANDRADE, D.A. New formulation for semi-empirical correlations for penetration jets. World Journal of Nuclear Science and Technology, v. 9, n. 2, p. 96-111, 2019. DOI: 10.4236/wjnst.2019.92007. Disponível em: http://repositorio.ipen.br/handle/123456789/30010. Acesso em: $DATA.

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Abstract: The use of Wireless Sensor Networks (WSN) associated with the reality of an Internet of Things (IoT) scenario in nuclear environments is a growing security concern. In this context, standards are intensified to preserve the physical integrity of these facilities considered to be highly critical due to the size of the impacts of safety accidents. This paper presents a proposal to build a methodology to evaluate the security levels of WSNs with IoT devices when used in nuclear areas. The proposal is initially based on related work to establish a more concrete initial framework and is structured in consistent steps from previous scientific studies.

Palavras-Chave: internet; computer networks; security; sensors; nuclear facilities; programming; recommendations; local area networks; information systems; documentation

SAVOINE, MARCIA M.; MENEZES, MARIO O. de; ANDRADE, DELVONEI A. de. Proposal of a methodology for the assessment of security levels of IoT wireless sensor networks in nuclear environments. World Journal of Nuclear Science and Technology, v. 8, n. 2, p. 78-85, 2018. DOI: 10.4236/wjnst.2018.82008. Disponível em: http://repositorio.ipen.br/handle/123456789/29001. Acesso em: $DATA.

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Abstract: The presence of a potentially hazardous facility in a community demands several safety procedures. Bringing risk communication among those actions may help the population that lives near the facility feel more confident and have the required knowledge on how to behave in an emergency situation. A research performed in Angra dos Reis, RJ, Brazil, where a nuclear power plant is located, shows that there is a lack of information and awareness about the emergency plan.

Palavras-Chave: hazards; communications; emergency plans; nuclear power plants; brazilian organizations; angra-1 reactor; angra-2 reactor

CUNHA, RAQUEL D.S. da; ANDRADE, DELVONEI A. de. Risk communication and external emergency plan in Angra dos Reis, Brazil. World Journal of Nuclear Science and Technology, v. 6, p. 301-308, 2016. DOI: 10.4236/wjnst.2016.64027. Disponível em: http://repositorio.ipen.br/handle/123456789/26991. Acesso em: $DATA.

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Abstract: Several fuel plants that supply nuclear research reactors need to increase their production capacity in order to meet the growing demand for this kind of nuclear fuel. After the enlargement of the production capacity of such plants, there will be the need of managing the new production level. That level is usually the industrial one, which poses challenges to the managerial staff. Such challenges come from the fact that several of those plants operate today on a laboratorial basis and do not carry inventory. The change to the industrial production pace asks for new actions regarding planning and control. The production process based on the hydrolysis of UF6 is not a frequent production route for nuclear fuel. Production planning and control of the industrial level of fuel production on that production route is a new field of studies. The approach of the paper consists in the creation of a mathematical linear model for minimization of costs. We also carried out a sensitivity analysis of the model. The results help in minimizing costs in different production schemes and show the need of inventory. The mathematical model is dynamic, so that it issues better results if performed monthly. The management team will therefore have a clearer view of the costs and of the new, necessary production and inventory levels.

Palavras-Chave: fabrication; uranium silicides; fuels; reactors; production; planning; control; mathematical models

NEGRO, MIGUEL L.M.; DURAZZO, MICHELANGELO; MESQUITA, MARCO A. de; CARVALHO, ELITA F.U. de; ANDRADE, DELVONEI A. de. Studies on production planning of dispersion type U3Si2-Al fuel in plate-type fuel elements for nuclear research reactors. World Journal of Nuclear Science and Technology, v. 6, p. 217-231, 2016. DOI: 10.4236/wjnst.2016.64023. Disponível em: http://repositorio.ipen.br/handle/123456789/27000. Acesso em: $DATA.

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Abstract: This work aims to present the historical context in which the current understanding of the phenomenon of the direct contact condensation started to call the scientific society attention. The development of nuclear power plants Light Water Reactors demanded a safe way to collect and treat the water used to cool the reactor. Some characteristics of this water in a high energetic thermodynamic state made it unsuitable to be directly discharged in the atmosphere. Small room relieves tanks were developed to contain this discharge. These tanks were partially fulfilled with water, and the vapor injection created a vapor plume. In the interface of liquid and vapor, the thermal exchange would be increased by the characteristic turbulence of this region.

Palavras-Chave: propulsion systems; submarines; nuclear ships; ship propulsion reactors; emergency plans; cooling systems; vapor condensation; heat transfer; water; nuclear energy; nuclear weapons; technology utilization

PACHECO, RAFAEL R.; ANDRADE, DELVONEI A. de. Technological perspectives for propulsion on nuclear attack submarines. World Journal of Nuclear Science and Technology, v. 8, n. 1, p. 1-10, 2018. DOI: 10.4236/wjnst.2018.81001. Disponível em: http://repositorio.ipen.br/handle/123456789/28985. Acesso em: $DATA.

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Abstract: 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.

Palavras-Chave: thermal hydraulics; reactors; research reactors; uranium; fuel assemblies; iear-1 reactor; flow rate; loss of coolant; materials testing reactors; eccs

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. Thermal hydraulic analysis improvement for the IEA-R1 research reactor and fuel assembly design modification. World Journal of Nuclear Science and Technology, v. 8, n. 2, p. 54-69, 2018. DOI: 10.4236/wjnst.2018.82006. Disponível em: http://repositorio.ipen.br/handle/123456789/29014. Acesso em: $DATA.

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