RAFAEL CARDOSO BAPTISTINI PESTANA

RAFAEL CARDOSO BAPTISTINI PESTANA

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The use of nuclear forensic library in order to identify unknown seized nuclear material. Brazilian’s participation in the galaxy serpent exercise
2017 - SARKIS, J.E.S.; BORDON, I.C.A.C.; PESTANA, R.C.B.
Nuclear fission is governed by very well known physical laws which, under certain circumstances, for instance: type of reactor, fuel and irradiation history, allow to preview with high degree of confidence, the production of energy, the build up of fission products and the transmutation of heavy metals. All these information, gathered in a nuclear forensic library (NFL), can be an important tool during the identification of a seized unknown sample, allowing to produce evidences concerning it’s irradiation history, the type of reactor or even the origin of the sample. The usefulness of a nuclear forensic library depending on not only the quantity or quality of the available data, as well as the capacity of the investigators to identify, correlate, and interpret the main parameters identified, or measured, in the seized sample. In this paper it will be described the strategy adopted by the Brazilian’s team during the Galaxy Serpent Exercise, coordinated by the Nuclear Forensics International Technical Working Group on nuclear forensics, where a NFL was used to identify an unknown sample. Our experience demonstrated the importance of the knowledge on nuclear reactions to select the main parameters to be considered during the evaluation. Then, the importance to use of simple isotopic correlations, to verify the consistency of the available information, before to use a more complex multivariate statistical techniques . Based on our investigation, the following questions were answered: Does Clio reactor belong to the NFL? Is it possible to identify which class of reactor belongs Clio? For the first question the answer is: Conclusive negative. For the second question the answer is: suggestive positive to be a BWR reactor.
The use of SEM-EDX for the identification of uranium compounds in swipe samples for nuclear safeguards
2017 - SARKIS, J.E.S.; PESTANA, R.C.B.; MARIN, R.C.; CARVALHO, E.F.U.
Environmental swipe sampling for safeguards purposes has been used by International Atomic Energy Agency since 1996 and is a powerful tool to detect undeclared materials and activities in States under safeguards agreements. The Secondary Electron Microscope with Energy-Dispersive X-Ray analyzing system (SEM-EDX) can be particularly useful in the initial identification of uranium in swipe samples and might be appropriate to identify and characterize uranium particles This work describes the use of SEM-EDX, as an initial screening technique, in real-life swipe samples for identifying and characterizing uranium particles. The swipe samples were collected in a conversion plant at the Nuclear and Energy Research Institute – IPEN/CNEN, São Paulo, Brazil
The use of ICP-MS and LA-ICP-MS techniques for uranium analysis in real-life swipe samples for safeguards purposes
2017 - SARKIS, J.E.S.; PESTANA, R.C.B.; MARIN, R.C.; ABREU-JUNIOR, C.H.; CARVALHO, E.F.U.
Environmental swipe sampling is a powerful tool to detect undeclared materials and activities in States under safeguards agreements and has been used by the International Atomic Energy Agency since 1996. This work describes the utilization of the inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for determining uranium isotopic ratios in a real-life swipe samples collected in a conversion plant at IPEN/CNEN, Brazil. Uncertainties were estimated by following the International Organization for Standardization –Guide to the Expression of Uncertainties in Measurement (ISO GUM), with a confidence level of 95%.
The use of laser ablation sector field inductively coupled plasma mass spectrometry for swipe samples analysis
2017 - SARKIS, J.E.S.; MARIN, R.C.; PESTANA, R.C.B.
This work describes the utilization of laser ablation sector field inductively coupled plasma mass spectrometry (LA-SF-ICP-MS) for determining uranium isotopic composition in a simulated swipe sample by deposition of U3O8 powder with natural enrichment level. This method is useful to measure 234U/238U and 235U/238U isotopic ratios. The measurements were performed on a continuous ablation with low energy density and defocusing, which improved the signal stability, in a cluster of uranium particles. Optimization of measurements was achieved by adjusting the following parameters: RF power, laser beam diameter, defocusing of laser beam, laser energy, laser energy-density, auxiliary gas and sample gas. The 235U/238U isotope ratio was 0.00719 0.00020 and its precision was 1.2 % RSD (relative standard deviation). Uncertainties were estimated following the International Organization for Standardization – Guide to the Expression of Uncertainty in Measurement (ISO – GUM), with a confidence level of 95.45% (k = 2.00). The results indicate that the Laser Ablation ICP-MS technique offers a rapid and accurate alternative for the measurement of uranium isotope ratios in uranium particle. The technique has the added advantage of allowing measurements straight on the sample (without further preparation), preserving the testimony which is very important for safeguards and nuclear forensics purposes.
Nuclear forensics
2017 - SARKIS, J.E.S.; MARIN, R.C.; PESTANA, R.C.B.
The use of environmental monitoring as a technique to identify activities related to the nuclear fuel cycle has been proposed, by international organizations, as an additional measure to the safeguards agreements in force. The elements specific for each kind of nuclear activity, or "nuclear signatures", inserted in the ecosystem by several transfer paths, can be intercepted with better or worse ability by different live organisms. Depending on the kind of signature of interest, the anthropogenic material identification and quantification require the choice of adequate biologic indicators and, mainly, the use of sophisticated techniques associated with elaborate sample treatments. This work demonstrates the technical viability of using pine needles as bioindicators of nuclear signatures associated with uranium enrichment activities. Additionally, it proposes the use of a technique widely diffused nowadays in the scientific community, the High Resolution Inductively Coupled Plasma Mass Spectrometer (HR-ICP-MS), to identify the signature corresponding to that kind of activities in the ecosystem. It can be also found a description of a methodology recently being applied in analytical chemistry, based on uncertainties estimates metrological concepts, used to calculate the uncertainties associated with the obtained measurement results. Nitric acid solutions with a concentration of 0.3 mol kg􀀀1, used to wash pine needles sampled near facilities that manipulate enriched uranium and containing only 0.1 g kg􀀀1 of uranium, exhibit a 235U:238U isotopic abundance ratio of 0.0092 ? 0.0002, while solutions originated from samples collected at places located more than 200 km far from activities related to the nuclear fuel cycle exhibit a value of 0.0074 ? 0.0002 for this abundance ratio. Similar results were obtained for sample solutions prepared by microwave assisted acid digestion and dry ashing process. The different values of 235U:238U isotopic abundance ratio obtained for samples collected in different places permit to confirm the presence of anthropogenic uranium and demonstrate the viability of using this technique and the methodology proposed in this work.
Brazil's participation in the galaxy serpent exercise
2014 - SARKIS, JORGE E.S.; BORDON, ISABELLA C.A.C.; PESTANA, RAFAEL C.B.; MARIN, RAFAEL C.
The use of laser ablation sector field inductively coupled plasma mass spectrometry for swipe samples analysis: a viewpoint from safeguard and nuclear forensic
2013 - MARIN, RAFAEL C.; SARKIS, JORGE E.S.; PESTANA, RAFAEL C.B.
Nuclear forensics: strategies and analytical techniques
2013 - MARIN, RAFAEL C.; SARKIS, JORGE E.S.; PESTANA, RAFAEL C.B.
The use of SEM-EDX for the identification of uranium compounds in swipe samples for nuclear safeguards
2013 - PESTANA, RAFAEL C.B.; SARKIS, JORGE E.S.; MARIN, RAFAEL C.; CARVALHO, ELITA F.U.
The use of ICP-MS and LA-ICP-MS techniques for uranium analysis in real-life swipe samples for safeguards purposes
2013 - PESTANA, RAFAEL C.B.; SARKIS, JORGE E.S.; MARIN, RAFAEL C.; ABREU JUNIOR, CASSIO H.; CARVALHO, ELITA F.U.