Modeling of the radiation measurement device FALCON 5000 by MCNPX: simulated efficiency for the on-site measurement

In order to evaluate the efficiency of the new spectrometry detector available in the STEP unit of the R&D from EDF, a numerical model of the FALCON 5000 radiation measurement system, based on the Ge technology, has been constructed thanks to the computer calculation code MCNPX. Due to the ignorance of the source term and the geometry of irradiation in our facilities, some cases of irradiation induce by a radioactive source has been planed to be simulated with different parameters which has been studied. For different energies and different distances and angles of incidence, simulations have been performed in order to assess an average the response of the modeled detector by MCNPX. Thanks to all these results, a global curve for the efficiency has been established taking into account of the energy, the distance between the source and the detector and the angle of incidence of the photon. The modeling of the detector, its validation and the efficiency curve have been presented in this paper

Feasibility study for a realistic training dedicated to radiological protection improvement

Any personnel involved in activities within the controlled area of a nuclear facility must be provided with appropriate radiological protection training. An evident purpose of this training is to know the regulation dedicated to workplaces where ionizing radiation may be present, in order to properly carry out the radiation monitoring, to use suitable protective equipments and to behave correctly if unexpected working conditions happen. A major difficulty of this training consist in having the most realistic reading from the monitoring devices for a given exposure situation, but without using real radioactive sources. A new approach is developed at EDF R&D for radiological protection training. This approach combines different technologies, in an environment representative of the workplace but geographically separated from the nuclear power plant: a training area representative of a workplace, a Man Machine Interface used by the trainer to define the source configuration and the training scenario, a geolocalization system, fictive radiation monitoring devices and a particle transport code able to calculate in real time the dose map due to the virtual sources. In a first approach, our real-time particles transport code, called Moderato, used only an attenuation low in straight line. To improve the realism further, we would like to switch a code based on the Monte Carlo transport of particles method like Geant 4 or MCNPX instead of Moderato. The aim of our study is the evaluation of the code in our application, in particular, the possibility to keep a real time response of our architecture

Sensory exploration of the freshness sensation in plain yoghurts and yoghurt-like products

WOS: 000324008600021 ; http://www.sciencedirect.com/science/article/pii/S0950329313001092International audienceThe term "freshness sensation" is used by consumers for characterizing some plain yoghurts and yoghurt-like products. This study consisted in an investigation of this sensation aiming at determining its underlying sensory attributes. First, two focus groups of consumers were conducted to open up the framework. A set of plain yoghurts and yoghurt-like products, both commercial and experimental, was then subjected to sensory analysis. The samples were sorted by means of a free sorting task, and further scored for the intensity of their freshness sensation and their liking, by 72 untrained consumers. Temporal Dominance of Sensations (TDS) measurements were performed by a trained sensory panel on the same products. The holistic notations of the freshness sensation and TDS results were finally combined using an internal mapping methodology. Freshness sensation and liking were highly correlated. However, a product with a low liking score was evaluated as giving an intense freshness sensation. A strong consensus of untrained subjects was observed on the fermented milk with the lowest freshness sensation intensity. Fermented milks with the highest freshness sensation intensity were the ones with the highest fat content. The main characteristics of the freshness sensation in yoghurts and yoghurt-like products were a sensation of decrease in the mouth temperature, followed by a fluid texture together with a cream flavor. A thick texture followed by the sensations of acidity and astringency clearly appeared to decrease the freshness sensation of the products. The key sensory attributes of the freshness sensation were highlighted by classical sensory approaches (free sorting task, freshness sensation scoring and focus groups). Their temporal order was determined by the TDS methodology. This could be valuable for formulating fresher products