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An Integrated Approach for Process Control Valves Diagnosis Using Fuzzy Logic

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World Journal of Nuclear Science and Technology 2014年第3期4卷 148-157页

作者： Alvaro Luiz G.Carneiro Almir C.S.Porto Jr. Nuclear Energy Research Institute/National Nuclear Energy Commission(IPEN/CNEN—SP) Sao PauloBrasil navy Technology center/navy Ministry(CTMSP/MB) Sao PauloBrasil

Control valves are widely used in industry to control fluid flow in several applications. In nuclear power systems they are crucial for the safe operation of plants. Therefore, the necessity of improvements in monitoring and diagnosis methods started to be of extreme relevance, establishing as main goal of the reliability and readiness of the system components. The main focus of this work is to study the development of a model of non-intrusive monitoring and diagnosis applied to process control valves using artificial intelligence by fuzzy logic technique, contributing to the development of predictive methodologies identifying faults in incipient state. Specially in nuclear power plants, the predictive maintenance contributes to the security factor in order to diagnose in advance the occurrence of a possible failure, preventing severs situations. The control valve analyzed belongs to a steam plant which simulates the secondary circuit of a PWR—Pressurized Water Reactor. The maintenance programs are being implemented based on the ability to diagnose modes of degradation and to take measures to prevent incipient failures, improving plant reliability and reducing maintenance costs. The approach described in this paper represents an alternative departure from the conventional qualitative techniques of system analysis. The methodology used in this project is based on signatures analysis, considering the pressure (psi) in the actuator and the stem displacement (mm) of the valve. Once the measurements baseline of the control valve is taken, it is possible to detect long-term deviations during valve lifetime, detecting in advance valve failures. This study makes use of MATLAB language through the “fuzzy logic toolbox” which uses the method of inference “Mamdani”, acting by fuzzy conjunction, through Triangular Norms (t-norm) and Triangular Conorms (t-conorm). The main goal is to obtain more detailed information contained in the measured data, correlating them to failure sit

关键词： Process Control Valve Condition Monitoring Diagnosis System Fuzzy Logic

Revisiting Stainless Steel as PWR Fuel Rod Cladding after Fukushima Daiichi Accident

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Journal of Energy and Power Engineering 2014年第6期8卷 973-980页

作者： Alfredo Abe Claudia Giovedi Daniel de Souza Gomes Antonio Teixeira e Silva Nuclear Engineering center Nuclear and Energy Research Institute Brazilian Nuclear Energy Commission Sao Paulo05508-000 Brazil Laboratory for Developing of Nuclear Fuel and Instrumentation Navy Technological Center Sao Paulo 05508-000 Brazil

In the past, stainless steel was utilized as cladding in many PWRs （pressurized water reactors）, and its performance under irradiation was excellent. However, stainless steel was replaced by zirconium-based alloy as cladding material mainly due to its lower neutron absorption cross section. Now, stainless steel cladding appears as a possible solution for safety problems related to hydrogen production and explosion as occurred in Fukushima Daiichi accident. The aim of this paper is to discuss the steady-state irradiation performance using stainless steel as cladding. The results show that stainless steel rods display higher fuel temperatures and wider pellet-cladding gaps than Zircaloy rods and no gap closure. The thermal performance of the two rods is very similar and the neutron absorption penalty due to stainless steel use could be compensating by combining small increase in U-235 enrichment and pitch size changes.

关键词： Austenitic stainless steel cladding Zircaloy cladding PWR fuel rod steady-state fuel performance codes.

WAXD and FTIR Studies of Electron Beam Irradiated Biodegradable Polymers

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Journal of Physical Science and Application 2012年第4期2卷 80-87页

作者： Yasko Kodama Nelson Batista de Lima Clfiudia Giovedi Luci Diva Brocardo Machado Wilson Aparecido Parejo Calvol Akihiro Oishi Kazuo Nakayama Radiation Technology center Nuclear and Energy Research Institute (IPEN-CNEN/SP) Sao Paulo 05508-000 Brazil Science and Materials Technology center Nuclear and Energy Research Institute (IPEN-CNEN/SP) Sao Paulo 05508-000Brazil navy technological center in sao paulo (CTMSP) Sao Paulo 05508-000 Brazil Research Institute for Innovation in Sustainable Chemistry National Institute of Advanced Industrial Science and Technology(AIST) Ibaraki 3058565 Japan

Poly（L-lactic acid）（PLLA） and poly（e-caprolactone）（PCL） have been receiving much attention lately due to their biodegradability in human body as well as in the soil, also due to their biocompatibility, environmentally friendly characteristics and non-toxicity. Morphology of biodegradable polymers affects the rate of their biodegradation. A polymer that has high degree of crystallinity will degrade at a slower rate due to the inherent increased stability. PCL homopolymer crosslinking degree increases with increasing doses of high energy radiation. On the other hand, the irradiation ofPLLA homopolymer promotes mainly chain-scissions at doses below 250 kGy. In the present work, twin screw extruded films of PLLA and PCL biodegradable homopolymers and 50：50 （w：w） blend were electron beam irradiated using electron beam accelerator Dynamitron （E = 1.5 MeV） from Radiation Dynamics, Inc. at doses in the range of 50 kGy to 103 kGy in order to evaluate the effect of electron beam radiation. Wide-angle X-ray diffraction （WAXD） patterns of non irradiated and irradiated samples were obtained using a diffractometer Rigaku Denki Co. Ltd., Multiflex model; and Fourier transform infrared spectroscopy （FTIR） spectra was obtained using a NICOLET 4700, attenuated total reflectance （ATR） technique. By WAXD patterns of as extruded non irradiated and irradiated PLLA it was verified broad diffusion peaks corresponding to amorphous polymer. There was a slight increase of the mean crystallite size of PCL homopolymer with increasing radiation dose. PCL crystalline index （CI） decreased with radiation dose above 500 kGy. But then, PLLA CI increased with radiation dose above 750 kGy. From another point of view, PLLA presence on the 50：50 blend did not interfere on the observed mean crystallite size increase up to 250 kGy. From 500 kGy to 103 kGy the crystallite size of PCL was a little bigger in the blend than the homopolymer. In contrast, FTIR results have shown that this technique was not sen

关键词： Biodegradable polymers PLLA PCL electron beam WAXD FTIR.

Atlas-B： Development and Testing of a Brazilian Deep-Ocean Moored Buoy for Climate Research

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Journal of Shipping and Ocean Engineering 2014年第5期4卷 140-151页

作者： Edmo J.D. Campos Carlos A.S. Franca Francisco L. Vicentini Neto Luiz V. Nonnato Alberto R. Piola Leonardo Barreira Rick Cole paulo Nobre Janie Trotte-Duha Laboratory for Modeling and Observation of the Ocean Institute of Oceanography University of Sao Paulo Sao Paulo05508-120 Brazil Naval Hydrographical Service and University of Buenos Aires Buenos Aires C12 70ABV Argentina IPqM (Research Institute of the Brazilian navy) Rio de Janeiro 21931-095 Brazil RDSea International St. Pete Beach Florida 33706 USA INPE (National Institute for Space Research) CPTEC (Center for Climate Research and Weather Prediction) Cachoeira Paulista12630-000 Brazil MCTI(Brazilian Ministery for Science Technology and Innovation) Brasilia 70067-900 Brazil

The PIRATA-SWE （Prediction and Research Moored Array in the Tropical Atlantic-Southwest Extension） was conceived in the early 2000s to gather observations necessary to improve the understanding of the variability of ocean-atmosphere interactions in the SACZ （South Atlantic Convergence Zone）, which are believed to influence South American climate. To properly monitor the SACZ, the preliminary design for the PIRATA-SWE array considered the mooring of four buoys, with the southernmost one in the sub-tropics. In 2005, three buoys were deployed in the tropical region. Four years later, in 2009, efforts were started to assemble and deploy a Brazilian prototype of the TAO/PIRATA Atlas （autonomous temperature line acquisition system） buoy-the Atlas-B. Finally, in April 2013 the first Atlas-B, nicknamed ＂Guariroba＂, was moored for a testing period at 28.5° S, 44° W, which is the site originally planned for the fourth PIRATA-SWE buoy. In early November 2013, after being detected adrift, the buoy with the upper 700 m part of the mooring line was rescued in an emergency operation. In June 2014, the bottom part was successfully recovered. A new deployment is planned for late 2014. This paper describes part of the learning process of adapting and building the Atlas-B buoy and presents a brief discussion of the data collected during the pilot deployment.

关键词： Atlas-B Buoy PIRATA Southwest Atlantic hurricane Catarina SACZ.