Van Houdt R.,Belgian Nuclear Research Center |
Michiels C.W.,Catholic University of Leuven
Journal of Applied Microbiology | Year: 2010
The ability of many bacteria to adhere to surfaces and to form biofilms has major implications in a variety of industries including the food industry, where biofilms create a persistent source of contamination. The formation of a biofilm is determined not only by the nature of the attachment surface, but also by the characteristics of the bacterial cell and by environmental factors. This review focuses on the features of the bacterial cell surface such as flagella, surface appendages and polysaccharides that play a role in this process, in particular for bacteria linked to food-processing environments. In addition, some aspects of the attachment surface, biofilm control and eradication will be highlighted. © 2010 The Society for Applied Microbiology.
Perko T.,Belgian Nuclear Research Center
Journal of Environmental Radioactivity | Year: 2014
Determining the differences in the perception of risks between experts who are regularly exposed to radiation, and lay people provides important insights into how potential hazards may be effectively communicated to the public. In the present study we examined lay people's (N=1020) and experts' (N=332) perception of five different radiological risks: nuclear waste, medical x-rays, natural radiation, an accident at a nuclear installation in general, and the Fukushima accident in particular. In order to link risk perception with risk communication, media reporting about radiation risks is analysed using quantitative and qualitative content analyses. The results showed that experts perceive radiological risks differently from the general public. Experts' perception of medical X-rays and natural radiation is significantly higher than in general population, while for nuclear waste and an accident at a nuclear installation, experts have lower risk perception than the general population. In-depth research is conducted for a group of workers that received an effective dose higher than 0.5mSv in the year before the study; for this group we identify predictors of risk perception. The results clearly show that mass media don't use the same language as technical experts in addressing radiological risks. The study demonstrates that the discrepancy in risk perception and the communication gap between the experts and the general population presents a big challenge in understanding each other. © 2013 Elsevier Ltd.
Vandenhove H.,Belgian Nuclear Research Center
Annals of Nuclear Energy | Year: 2013
The application of nuclear energy and the use of radionuclides for industrial, medical and research purposes have caused significant contamination of certain sites and their environment, which could result in health problems for several centuries if nothing is undertaken to remedy these situations. Except for the immediate environment of the facility, where decontamination activities may be feasible and affordable, the contamination often extents over a vast area and decontamination would be costly and could result in vast amounts of waste. Therefore, more realistic yet efficient remediation options should be searched for of which phytomanagement is among the potential options. A number of phytomanagement approaches will be discussed. © 2013 Elsevier Ltd. All rights reserved.
Lambrecht M.,Belgian Nuclear Research Center |
Malerba L.,Belgian Nuclear Research Center
Acta Materialia | Year: 2011
The irradiation-induced behaviour of iron-chromium model alloys and high chromium ferritic/martensitic steels have been studied using positron annihilation measurements. Both the positron lifetime and coincidence Doppler broadening techniques were used in a complementary way. It is shown that the presence of chromium in iron-based alloys significantly reduces the concentration of vacancies to the extent that the formation of clusters is hindered. The observed vacancy behaviour as a function of the chromium content is fully consistent with the findings of void swelling suppression in chromium-rich alloys and can be rationalized based on existing models. Finally, the information obtained for the ferritic/martensitic steels shows good agreement with the results for binary model alloys. Compared with the vacancy behaviour in pure iron, this confirms the major influence of chromium on the nanostructural evolution of these steels under irradiation. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Bruggeman C.,Belgian Nuclear Research Center |
Maes N.,Belgian Nuclear Research Center
Environmental Science and Technology | Year: 2010
The uptake of uranium(VI) by natural pyrite, FeS2, was studied under conditions relevant for geological disposal of radioactive waste (anoxic atmosphere, ∼0.014 mol·L-1 NaHCO3 electrolyte) with special emphasis on the role of dissolved organic matter. Solution analysis of batch experiments with different initial concentrations of uranium(VI) (10-8-10-4 mol·L-1) was combined with X-ray absorption spectroscopy on the solid phase to elucidate the speciation of uranium in these systems and to gain insight into the major reaction mechanisms between uranium and pyrite. The results showed that, under the conditions of the experiments, uranium(VI) was at least partly reduced to a UO 2(s)-like precipitate, although the predominant valence state of uranium in solution was likely uranium(VI). All observations indicate that the uranium solid-liquid distribution is governed by both reduction and adsorption processes. No significant amounts of uranium colloids (either intrinsic UO 2 colloids or complexes with natural organic matter) were found in any of the samples. The presence of dissolved organic matter did, however, increase the final uranium solution concentration and decrease the fraction of uranium(IV) found in the solid phase. © 2010 American Chemical Society.
Gusarov A.,Belgian Nuclear Research Center |
Hoeffgen S.K.,Fraunhofer Institute for Technological Trend Analysis
IEEE Transactions on Nuclear Science | Year: 2013
Fiber Bragg and long period gratings are photonic components that find numerous applications in telecommunication and sensing. In some cases, such as space, high-energy physics, and nuclear industry, those applications include the presence of ionizing radiation. It is therefore essential to evaluate their radiation response. In this paper, we review radiation effects on various types of fiber gratings. © 1963-2012 IEEE.
Abderrahim H.A.,Belgian Nuclear Research Center
International Journal of Energy Research | Year: 2012
Multi-purpose hYbrid Research Reactor for High-tech Applications (MYRRHA) is the flexible experimental accelerator-driven system in development at SCK•CEN. The MYRRHA facility, currently developed with the aid of the FP7-project 'Central Design Team' is conceived as a flexible irradiation facility. MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV systems, material developments for fusion reactors, radioisotope production for medical and industrial applications, and Si-doping. MYRRHA will also demonstrate the accelerator-driven system full concept by coupling the three components (accelerator, spallation target and subcritical reactor) at reasonable power level to allow operation feedback, scalable to an industrial demonstrator and allow the study of efficient transmutation of high-level nuclear waste. Because MYRRHA is based on the heavy liquid metal technology, lead-bismuth eutectic, it will be able to significantly contribute to the development of Lead Fast Reactor (LFR) Technology, and in critical mode, MYRRHA will play the role of the European Technology Pilot Plant in the roadmap for LFR. © 2011 John Wiley & Sons, Ltd.
Batlle J.V.I.,Belgian Nuclear Research Center
Integrated Environmental Assessment and Management | Year: 2011
The accident at the Fukushima Daiichi nuclear power plant, precipitated by the earthquake and subsequent tsunami that struck the northeastern coast of Japan in March 2011, has raised concerns about the potential impact to marine biota posed by the release of radioactive water and radionuclide particles into the environment. The Fukushima accident is the only major nuclear accident that has resulted in the direct discharge of radioactive materials into a coastal environment. This article briefly summarizes what is currently understood about the effects of radioactive wastewaters and radionuclides to marine life. © 2011 SETAC.
Vives I Batlle J.,Belgian Nuclear Research Center
Radiation and Environmental Biophysics | Year: 2012
In the present paper, a two-age-class group, logistic growth model for generic populations of nonhuman biota is described in order to assess non-stochastic effects of low linear energy-transfer radiation using three endpoints: repairable radiation damage, impairment of reproductive ability and, at higher radiation dose rates, mortality. This model represents mathematically the exchange between two life stages considering fecundity, growth and mortality. Radiation effects are modeled with a built-in self-recovery pool whereupon individuals can repair themselves. In acute effects mode, the repairing pool becomes depleted due to radiation and the model tends to lethality mode. A base calibration of the model's two free parameters is possible assuming that in acute mode 50 % of the individuals die on 30 days when a radiation dose equal to the LD 50/30 is applied during that period. The model, which requires 10 species-dependent life-history parameters, was applied to fish and mammals. Its use in the derivation of dose-rate screening values for the protection of non-human biota from the effects of ionizing radiation is demonstrated through several applications. First, results of model testing with radiation effects data for fish populations from the EPIC project show the predictive capability of the model in a practical case. Secondly, the model was further verified with FREDERICA radiation effects data for mice and voles. Then, consolidated predictions for mouse, rabbit, dog and deer were generated for use in a population model comparison made within the IAEA EMRAS II project. Taken together, model predictions suggest that radiation effects are more harmful for larger organisms that generate lower numbers of offspring. For small mammal and fish populations, dose rates that are below 0.02 Gy day -1 are not fatal; in contrast, for large mammals, chronic exposure at this level is predicted to be harmful. At low exposure rates similar to the ERICA screening dose rate of 2.4 × 10 -4 Gy day -1, long-term effects on the survivability of populations are negligible, supporting the appropriateness of this value for radiological assessments to wildlife. © Springer-Verlag 2012.
Gusarov A.,Belgian Nuclear Research Center
IEEE Transactions on Nuclear Science | Year: 2010
We report the results of a long-term exposure of fiber Bragg gratings in the BR1 low-flux nuclear reactor at SCK·CEN in Mol, Belgium. Gratings fabricated in the photosensitive and the standard fibers were installed in February 2000 in a research channel of the reactor and remained there until August 2008. During this time the reactor was operational 4690h so that the gratings received a total thermal/fast neutron fluence ∼16.9/1.47 × 1017 n/cm2, and a gamma-dose ∼ 10 MGy. The temperature cycled from 10 to 80 °C. All the gratings were easily detectable at the end of the experiment. After more than eight years exposure the amplitude and the shape of the gratings spectra remained unchanged for fibers devoid of hydrogen loading, while FBGs fabricated using hydrogen loading did exhibit moderate changes. The results show that fiber Bragg gratings indeed have potential for long-term temperature monitoring in nuclear installations. © 2010 IEEE.