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  • 1.
    Björkbacka, Åsa
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Hosseinpour, Saman
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Johnson, Magnus
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Radiation induced corrosion of copper for spent nuclear fuel storage2013In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 92, p. 80-86Article in journal (Refereed)
    Abstract [en]

    The long term safety of repositories for radioactive waste is one of the main concerns for countries utilizing nuclear power. The integrity of engineered and natural barriers in such repositories must be carefully evaluated in order to minimize the release of radionuclides to the biosphere. One of the most developed concepts of long term storage of spent nuclear fuel is the Swedish KBS-3 method. According to this method, the spent fuel will be sealed inside copper canisters surrounded by bentonite clay and placed 500 m down in stable bedrock. Despite the importance of the process of radiation induced corrosion of copper, relatively few studies have been reported. In this work the effect of the total gamma dose on radiation induced corrosion of copper in anoxic pure water has been studied experimentally. Copper samples submerged in water were exposed to a series of total doses using three different dose rates. Unirradiated samples were used as reference samples throughout. The copper surfaces were examined qualitatively using IRAS and XPS and quantitatively using cathodic reduction. The concentration of copper in solution after irradiation was measured using ICP-AES. The influence of aqueous radiation chemistry on the corrosion process was evaluated based on numerical simulations. The experiments show that the dissolution as well as the oxide layer thickness increase upon radiation. Interestingly, the evaluation using numerical simulations indicates that aqueous radiation chemistry is not the only process driving the corrosion of copper in these systems.

  • 2.
    Brena, Barbara
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Time-dependent DFT calculations of core electron shake-up states of metal-(free)-phthalocyanines2006In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 75, no 11, p. 1578-1581Article in journal (Refereed)
    Abstract [en]

    We have introduced a new approach for the calculation of the shake-up structures of molecular photoelectron spectra, based on the combination of time-dependent density functional theory (TD-DFT) and equivalent core hole (or Z + 1) approximation. The method, suitable for large molecules, has been applied to compute the complex shake-up states associated with the carbon Is X-ray photoelectron spectroscopy (XPS) of metal-free and nickel phthalocyanines (H2Pc and NiPc, respectively). A similar satellite profile emerges for both molecules.

  • 3. Gao, Bin
    et al.
    Zhong, Jun
    Song, Li
    Wu, Zi-Yu
    Xie, Sishen
    Qian, Haijie
    Dong, Yuhui
    Luo, Yi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry (closed 20110512).
    Studies of bromine modified single-walled carbon nanotubes using photoelectron spectroscopy and density-functional theory2006In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 75, no 11, p. 1939-1942Article in journal (Refereed)
    Abstract [en]

    Many applications based on single-walled carbon nanotubes (SWNTs) require chemical modification of carbon nanotube to optimize the functionalities of the device. In this contribution we discuss the properties of SWNTs immersed in a hydrobromic acid (HBr) solution. Changes of atomic and electronic structures of bromine modified SWNTs were investigated using photoelectron spectroscopy (PES). Spectra of SWNTs before and after immersion in the HBr solution exhibit different features. To understand the mechanism of interaction between SWNTs and bromine, we performed density-functional theory calculations to reveal the structural changes, adsorption energy and chemical bonding information of SWNTs interacting with bromine. In addition, based on the Gelius model, from the molecular orbitals (MOs), we calculated ultraviolet photoelectron spectra (UPS) of SWNTs with and without functionalizing and compared them with the experiment. The present study is a first step in the understanding of the functionalization mechanism of carbon nanotubes.

  • 4.
    Holmboe, Michael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Wold, Susanna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Influence of γ-radiation on the reactivity of Montmorillonite towards H2O22012In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 81, no 2, p. 190-194Article in journal (Refereed)
    Abstract [en]

    Compacted and water saturated bentonite will be used as an engineered barrier in deep geological repositories for radioactive waste in many countries. Due to the high dose rate of ionizing radiation outside the canisters holding the nuclear waste, radiolysis of the interlayer and pore water in the compacted bentonite is unavoidable. Upon reaction with the oxidizing and reducing species formed by water radiolysis (OH•, e-(aq), H•, H202, H2, H02•, H30+), the overall redox properties in the bentonite barrier may change. In this study the influence of γ-radiation on the structural Fe(II)/Fe(III) content in montmorillonite and its reactivity towards hydrogen peroxide (H2O2) was investigated in parallel experiments. The results show that under anoxic conditions the structural Fe(II)/FeTot ratio of dispersed montmorillonite are increased from ≤ 3 to 25-30% after γ-doses comparable to repository conditions. Furthermore, a strong correlation between the structural Fe(II)/FeTot ratio and the H2O2 decomposition rate in montmorillonite dispersions was found. This correlation was further verified in experiments with consecutive H2O2 additions, since the structural Fe(II)/FeTot ratio was seen to decrease concordantly. This work shows that the structural iron in montmorillonite could be a sink for one of the major oxidants formed upon water radiolysis in the bentonite barrier, H2O2.

  • 5.
    Holmboe, Michael
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Norrfors, Karin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Wold, Susanna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry (closed 20110630).
    Effect of γ-radiation on Radionuclide Retention in Compacted Bentonite2011In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 80, no 12, p. 1371-1377Article in journal (Refereed)
    Abstract [en]

    Compacted bentonite is proposed as an engineered barrier in many concepts for disposal of high level nuclear waste. After the initial deposition however, the bentonite barrier will inevitably be exposed to ionizing radiation (mainly gamma) under anoxic conditions. Because of this, the effects of gamma-radiation on the apparent diffusivity values and sorption coefficients in bentonite for Cs(+) and Co(2+) were tested under different experimental conditions. Radiation induced effects on sorption were in general more noticeable for Co(2+) than for Cs(+), which generally showed no significant differences between irradiated and unirradiated clay samples. For Co(2+) however, the sorption to irradiated MX80 was significantly lower than to the unirradiated clay samples regardless of the experimental conditions. This implies that gamma-radiation may alter the surface characteristics contributing to surface complexation of Co(2+). With the experimental conditions used, however, the effect of decreasing sorption was not large enough to be reflected on the obtained D. values.

  • 6.
    Norrfors, K. Karin
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Björkbacka, Åsa
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Kessler, Amanda
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Wold, Susanna
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    γ-radiation induced corrosion of copper in bentonite-water systems under anaerobic conditions2018In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 144, p. 8-12Article in journal (Refereed)
    Abstract [en]

    In this work we have experimentally studied the impact of bentonite clay on the process of radiation-induced copper corrosion in anoxic water. The motivation for this is to further develop our understanding of radiation-driven processes occurring in deep geological repositories for spent nuclear fuel where copper canisters containing the spent nuclear fuel will be embedded in compacted bentonite. Experiments on radiation-induced corrosion in the presence and absence of bentonite were performed along with experiments elucidating the impact irradiation on the Cu2+ adsorption capacity of bentonite. The experiments presented in this work show that the presence of bentonite clay has no or very little effect on the magnitude of radiation-induced corrosion of copper in anoxic aqueous systems. The absence of a protective effect similar to that observed for radiation-induced dissolution of UO2 is attributed to differences in the corrosion mechanism. This provides further support for the previously proposed mechanism where the hydroxyl radical is the key radiolytic oxidant responsible for the corrosion of copper. The radiation effect on the bentonite sorption capacity of Cu2+ (reduced capacity) is in line with what has previously been reported for other cations. The reduced cation sorption capacity is partly attributed to a loss of Al-OH sites upon irradiation.

  • 7.
    Polito, C.
    et al.
    Sapienza Univ, Morphogenesis & Tissue Engn SAIMLAL Dept, Rome, Italy.;Bambino Gesu Pediat Hosp, Med Phys Unit, Rome, Italy..
    Pellegrini, R.
    Ist Nazl Fis Nucl, Roma Sect 1, Rome, Italy.;Sapienza Univ, Dept Mol Med, Rome, Italy..
    Cinti, M. N.
    Ist Nazl Fis Nucl, Roma Sect 1, Rome, Italy.;Sapienza Univ, Dept Mol Med, Rome, Italy..
    De Vincentis, G.
    Sapienza Univ Rome, Dept Radiol Sci Oncol & Anat Pathol, Rome, Italy..
    Lo Meo, S.
    Ezio Clementel Res Ctr, ENEA, Bologna, Italy.;INFN Sect, Bologna, Italy..
    Fabbri, A.
    Sapienza Univ, Dept Mol Med, Rome, Italy..
    Bennati, Paolo
    KTH, School of Technology and Health (STH), Medical Engineering.
    Cencelli, V. Orsolini
    Roma III Univ, Dept Phys, Rome, Italy..
    Pani, R.
    Ist Nazl Fis Nucl, Roma Sect 1, Rome, Italy.;Sapienza Univ, Dept Sci & Med & Surg Biotechnol, Rome, Italy..
    Dual-modality imaging with a ultrasound-gamma device for oncology2018In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 147, p. 77-84Article in journal (Refereed)
    Abstract [en]

    Recently, dual-modality systems have been developed, aimed to correlate anatomical and functional information, improving disease localization and helping ontological or surgical treatments.& para;& para;Moreover, due to the growing interest in handheld detectors for preclinical trials or small animal imaging, in this work a new dual modality integrated device, based on a Ultrasounds probe and a small Field of View Single Photon Emission gamma camera, is proposed.

  • 8.
    Toijer, Elin
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Engineering. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Jonsson, Mats
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    H 2 O 2 and γ-radiation induced corrosion of 304L stainless steel in aqueous systems2019In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 159, p. 159-165Article in journal (Refereed)
    Abstract [en]

    In light-water reactors the water used as neutron moderator and coolant is subjected to a constant radiation field which leads to the formation of a number of oxidizing and reducing species. In this work, the reactivity of the radiolysis product H 2 O 2 towards the 304L alloy, commonly used for structural materials in nuclear power plants, was investigated as well as oxidative dissolution of steel components as a consequence of γ-radiation and chemically added H 2 O 2 . The concentration of hydrogen peroxide as a function of time was monitored in the presence of different amounts of steel powder, and the second order reaction rate constant was determined to k 2 = (1.8 ± 0.2) × 10 −10 m s −1 . In the case of catalytic decomposition of hydrogen peroxide, hydroxyl radicals are formed which can be scavenged by methanol. In this reaction formaldehyde is formed, which can be detected spectroscopically. A high yield of formaldehyde was observed, indicating that catalytic decomposition is the main reaction path of H 2 O 2 in the current system. A significant contribution of the homogeneous Fenton reaction to both the reaction rate constant and the formaldehyde formation must however be considered, as Fe(II) will be released from the oxide layer in solution. In the case of γ-irradiation, an increased nickel content in solution compared to background experiments is seen. When the steel is subjected to chemically added hydrogen peroxide on the other hand, the chromium content in solution is increased. This indicates that the different types of exposure will impact different parts of the oxide layer characterized by different composition. © 2019

  • 9.
    Yadav, Pooja
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Olsson, Richard T.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Nuclear Chemistry.
    Synthesis and characterization of MnO2 colloids2009In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 78, no 11, p. 939-944Article in journal (Refereed)
  • 10.
    Yang, Miao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry. Wuhan University of Technology, China.
    Soroka, Inna
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Jonsson, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Exploring the limitations of the Hantzsch method used for quantification of hydroxyl radicals in systems of relevance for interfacial radiation chemistry2017In: Radiation Physics and Chemistry, ISSN 0969-806X, E-ISSN 1879-0895, Vol. 130, p. 1-4Article in journal (Refereed)
    Abstract [en]

    In the presence of Tris or methanol, hydroxyl radicals in systems of relevance for interfacial radiation chemistry can be quantified indirectly via the Hantzsch method by determining the amount of the scavenging product formaldehyde formed. In this work, the influence of the presence of H2O2 on the Hantzsch method using acetoacetanilide (AAA) as derivatization reagent is studied. The experiments show that the measured CH2O concentration deviates from the actual concentration in the presence of H2O2 and the deviation increases with increasing [H2O2]0/[CH2O]0. The deviation is negative, i.e., the measured formaldehyde concentration is lower than the actual concentration. This leads to an underestimation of the hydroxyl radical production in systems containing significant amount of H2O2. The main reason for the deviation is found to be three coupled equilibria involving H2O2, CH2O and the derivative produced in the Hantzsch method.

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