A new meteorological pressure index to support a sustainable nuclear energy programme

Today, the evaluation of a site for innovative nuclear installations represents a fundamental step in supporting the implementation of a sustainable nuclear power program. One major concern is the potential for radioactive releases and their effects on the biosphere, particularly on human health. To address this issue, a new Meteorological Pressure Index (MPI) has been developed to identify sites with resilience capacity in terms of transport phenomena correlated to natural wind actions on a regional scale. The MPI utilizes a fuzzy approach that combines data on 3D wind speed, direction, and frequency, providing maps that are useful in the site selection process. The application of MPI in the Sicily region of Italy has allowed to identify bordering areas that that are more affected by efficient air mass transport mechanisms. Consistency analyses have been conducted among MPI maps, observed wind distributions using wind rose charts, and stagnation S and recirculation R factors. The results confirm the MPI's ability to aggregate meteorological data on a regional level, making it a suitable tool when compared to disaggregated data that may not always provide a comprehensive viewpoint

A new tool to process forecast meteorological data for atmospheric pollution dispersion simulations of accident scenarios: A Sicily-based case study

Emergency response plans to mitigate the severity of the accidental release of hazardous compounds in the air have become a primary concern in view of the many adverse events occurred over the years in high-risk plants. To do this, an accurate estimate of forecast meteorological data to be used in dispersion models can be very useful to respond in advance to emergency situations. In this field, FORCALM is a new tool developed to elaborate European Centre for Medium-Range Weather Forecasts data on a 3D computational domain with a high-resolution grid. FORCALM data can be used to perform predictive simulations of impacts on local and regional levels by using CALPUFF modelling system. A case study relevant to an accident, occurred in the “Mediterranea” Refinery at Milazzo (Italy) in 2014, has been also examined for validation purposes. A comparison with results obtained by using CALMET modelling system and observed meteorological data, covering the area under study, is also described. The validation work has allowed confirming that predictive assessments, carried out with the help of FORCALM, lead to information regarding potential environmental impacts with a good degree of accuracy

FMECA Application in Tomotherapy: Comparison between Classic and Fuzzy Methodologies

Accident analysis in radiotherapy highlighted the need to increase quality assurance (QA) programs by the identification of failures/errors with very low probability (rare event) but very severe consequences. In this field, a Failure Mode, Effects and Criticality Analysis (FMECA) technique, used in various industrial processes to rank critical events, has been met with much interest. The literature describes different FMECA methods; however, it is necessary to understand if these tools are incisive and effective in the healthcare sector. In this work, comparisons of FMECA methodologies in the risk assessment of patients undergoing treatments performed with helical tomotherapy are reported. Failure modes identified for the phases "treatment planning" and "treatment execution" are classified using the Risk Priority Number (RPN) index. Differences and similarities in the classification of failures/errors of the examined FMECA approaches are highlighted

RELAP5 simulation of two-phase flow experiments in vertical helical tubes

In the framework of the studies concerning the thermalfluid dynamic phenomena in helicoidal pipes of the innovative nuclear reactor IRIS steam generators, the Department of Nuclear Engineering of the University of Palermo in collaboration with the Politecnico di Torino Department of Energetics has been engaged in a work aimed to adapt, by implementing new suitable models, RELAP5/mod3.2.2β code to simulate the thermalfluid-dynamics and geometries such as the ones involved in helicoidal pipes. In fact this code is based on one-dimensional thermal-hydraulic relationships and presents limitations to model complicated geometry such as helicoidal pipes. Therefore the code was improved with additional correlations that are valid for two-phase flow and allow to overcome the drawbacks. The validation work of the models that were added is based on the experimental data carried out at the Politecnico di Torino Department of Energetics. In this paper it will be shown that the so modified RELAP5 code allows to represent adequately the experimental data

Codici termoidraulici per lo studio di processi in sistemi bifase multicomponenti

Dottorato di ricerca in energetica. 11. ciclo. Tutore Francesco Castiglia. Coordinatore Maurizio CumoConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Fuzzy risk analysis of a modern gamma-ray industrial irradiator

Fuzzy fault tree analyses were used to investigate accident scenarios that involve radiological exposure to operators working in industrial gamma-ray irradiation facilities. The HEART method, a first generation human reliability analysis method, was used to evaluate the probability of adverse human error in these analyses. This technique was modified on the basis of fuzzy set theory to more directly take into account the uncertainties in the error-promoting factors on which the methodology is based. Moreover, with regard to some identified accident scenarios, fuzzy radiological exposure risk, expressed in terms of potential annual death, was evaluated. The calculated fuzzy risks for the examined plant were determined to be well below the reference risk suggested by International Commission on Radiological Protection